"Oh, I forgot whether the waterwheel was invented by China! Tomorrow is Monday, and I have to hand in my homework. What should I do? " Danny, an eleven-year-old sixth-grade student, picked up the phone and dialed the hotline of the library to himself. Five minutes later, he sat down with satisfaction and began to write his report. This short story above is not science fiction. In fact, "calling your library" is one of the important ways for American citizens to contact the library. The service slogan put forward by Queen new york Library is "Trouble-making Library", which is similar to what we usually call "Trouble-making Police". Librarians will answer simple questions at any time; More complicated questions are generally answered within half an hour; Questions that cannot be answered for the time being will be answered by a special consulting department. Sometimes, in order to answer readers' questions satisfactorily, the library will copy and fax relevant materials to readers. There is generally no charge for copying materials that do not exceed 15 pages.

From the above two short stories that happened abroad, we can clearly see that in developed countries, library services are everywhere and embedded in people's work and even life. This is a place where domestic library services are relatively backward, and it is also worth learning from. The question-and-answer service provided by mobile library is just a good link to solve this problem, and it is also the most potential value-added service besides the basic functions of collection inquiry, renewal, reservation, loss reporting and expiration reminder. Librarians are professionals in information retrieval, and professional librarians have unparalleled information processing, filtering and retrieval capabilities relying on the resource advantages of libraries in professional fields. Can be more easily integrated into the professional field of staff and students, to solve problems and guide them. As the saying goes, there is specialization in the industry, and the information retrieval work is given to librarians, so that users have more time and space to solve or think about new problems.

Library reference service originated in America. 1836, Green, the father of library reference service, defined library reference service as "establishing personalized connection between library and readers"; 1885, Columbia university library has a special person in charge of reference and consultation. 1923 The Chicago Public Library has set up a reading guidance department in addition to the reference department ... Today, the reference service has basically become one of the core services of major libraries in the United States. China Library's reference service for readers can be traced back to the 20th century. 1928, the reference room of the National Library of China was established, which is regarded as one of the earliest reference service institutions of China Library. With the development of science and technology in the new century, the platform and mode of library reader reference service are constantly innovating, and the service content is more professional, diversified and personalized. As the most frequently used public library, doing a good job in reader reference service is obviously helpful to improve the level of library knowledge service and document information resource transmission.

The main contents of reference service for readers in professional libraries are the same, that is, librarians help readers to use documents and seek knowledge and information, and provide readers with facts, data and literature clues by assisting in retrieval, answering consultations and reporting special documents. Because professional libraries have a clear collection direction and professional reference services for readers' needs. The number of people covered by professional library services is very small. Mainly professional research scholars and students. The content of reader reference service is mainly based on the professional knowledge of the consultant, and the problems are concentrated and in-depth. It is necessary to provide the latest development trends of this discipline at home and abroad in a timely manner, involving the research field of professional disciplines. With the rapid development of reader-centered digital library, it is necessary to adjust the reference service for readers in time, which embodies the core concepts of knowledge transfer and knowledge appreciation.

The library has always been at the forefront of information technology, and now the service mode of the library is changing to a digital, virtual and networked service mode. The benefits brought by these changes are obvious, and they are also the necessary conditions for libraries to survive in the information explosion environment. Digital reference service is a new model for libraries to carry out information reference service under the digital information environment, and it is also an important part of the digital construction of modern and future new libraries. Users can search in the consulting service of the whole network according to their own needs, and they can find what they want quickly and accurately without being limited by system, time and region. It is really convenient and fast.

It is not unreasonable to vigorously develop the digital reference service mode of the library. The popularity of modern digital resources, people's attention to time and the popularity of fast and convenient services all determine that the consulting service model needs to be changed. More and more documents and databases are huge and difficult to query and extract; More and more people need to consult and extract the resources they need in time and properly. Digital reference service mode just meets people's needs, which makes this service mode popular and widely used. Another important reason is the rapid development of Internet technology. As an important carrier of this service model, the development of Internet technology makes the complicated information storage and extraction process simple. At the same time, the popularity of the network platform gives people the opportunity to access and use the network platform to obtain the information they need, which greatly promotes the development of the digital consulting service model. In addition, the change of knowledge resource carrier leads to the change of storage and reading methods. Nowadays, the most convenient, fast and safe carrier of all kinds of knowledge is digital configuration, which makes the management of resources more standardized and orderly, and the update of knowledge resource configuration also promotes the rapid development of digital reference service mode of libraries to some extent.

The library should be a bridge between readers and knowledge. It is easier for readers to get knowledge here than outside. Most libraries in China are just warehouses for storing knowledge, and sometimes it is even more complicated for readers to acquire knowledge than in Baidu and Google. This is why some libraries stay in study rooms and reading rooms. However, after all, the library has an innate resource advantage, and it is a waste of resources that cannot be fully utilized. Effective manual query is more important, and subject librarians came into being under this demand. Subject librarians help readers to build a bridge between knowledge, so that readers can acquire knowledge in a more effective way without spending a lot of time learning the skills of searching knowledge. The emergence of subject librarians has greatly improved the efficiency of readers' retrieval and knowledge acquisition, and subject service has also become an important embodiment of library service quality. Let's see how foreign libraries do it.

The University of Auckland, located in New Zealand, is the largest and most professional university in New Zealand and the top university in the world. University of Auckland has very strict regulations on the recruitment of subject librarians: subject librarians must have a master's degree or above in library; Familiar with and master the information resources of related disciplines, including the types, contents, use methods and skills of printing resources and electronic resources; Understand and update the information sources and new functions of this discipline in time; Have background knowledge or work experience in related disciplines; A comprehensive understanding of discipline construction and professional development direction; In-depth understanding of the collection resources construction of this discipline, including books, periodicals, databases, e-books and electronic periodicals; Master all kinds of knowledge and rules and regulations of the library; Regularly carry out information literacy training for teachers and students in designated disciplines. In addition, teaching ability, public relations ability, language expression ability and information technology are also indispensable basic skills for subject librarians. In the library of the University of Auckland, the services of subject librarians include: acting as the liaison between the library and the department (institute); Subject information resource service, that is, to assist teachers to provide relevant information resources and establish subject resource navigation according to the teaching needs of a professional course; Subject information literacy education provides information literacy teaching services, including information literacy curriculum design and participation in classroom teaching. Subject librarian assessment shall be conducted by the subject library director or the person in charge of the subject department according to the scope of duties and the contents of the post manual, with annual work summary and year-end salary promotion assessment. Each department submits the annual summary and year-end salary increase assessment report to the superior, and finally the chief curator decides whether to give them a salary increase according to the assessment results. Librarians of foreign languages have gradually expanded from knowledge workers in the construction of professional collection resources to knowledge disseminators, educators and information resource liaison officers, and played an active role in "consulting, taking charge of the collection management and development of their respective disciplines, playing a guiding role and playing a liaison role".

Domestic libraries should sum up the advanced experience of foreign libraries, and then combine the current situation of domestic libraries to formulate the development direction suitable for the library and provide more and better services for readers.

Reference service is one of the core businesses of the library, which embodies the overall service level of the library. Providing users with quality services is an important connotation of the spirit of reference and consultation. The organic combination of reference service and mobile library service can provide readers with asynchronous mode or real-time interactive mode consulting service anytime and anywhere, which is not affected by time and space, and makes readers feel that the library is by their side and the librarians are by their side. Although it is not "face-to-face" communication, with the development of information technology, "face-to-face" problem solving will eventually be realized anytime and anywhere.