1. reverse search method, a method of retrieving documents in reverse time by using retrieval tools, can quickly obtain the latest information.
2. The sequential search method uses the retrieval system to find documents in chronological order, which is usually suitable for retrieving documents with larger themes.
3. Direct method, a method of directly using retrieval tools to retrieve documents.
4. Traceability method, using different retrieval systems to find documents one by one.
5. Cycle method, which alternately uses direct method and backtracking method in time to achieve mutual cooperation, so as to obtain more perfect retrieval results.
Retrieval method is an important technical problem in literature retrieval. In the long-term literature retrieval practice, I have accumulated a set of literature retrieval methods, which can be summarized as follows:
1. Common methods.
The commonly used methods, also called tool method and direct retrieval method, are methods to find documents by using various existing retrieval tools (abstracts, indexes, etc.). ), including: forward query method and reverse query method.
(1) sequential search method.
From the year of the initial study, from far to near, check year by year until recently. This method is systematic, comprehensive and reliable, and generally does not miss the inspection, and the whole process of research and development of this subject can be seen from the documents detected year by year. However, this method is time-consuming and laborious, and it takes a lot of work to retrieve long-term topics.
(2) Reverse inspection method.
Contrary to the sequential search method, it searches from near to far, year after year, month after month, until it meets the subject's demand for literature. This method can quickly master valuable documents, with high accuracy and time saving, but there is the possibility of missing inspection. It is suitable for tactical information retrieval in subject research, focusing on mastering recent literature information and understanding the current level, trend and early development of subject research.
2. Retrospective method.
This is the traditional way to find documents. Based on the references attached to each paper, the retrospective search was carried out. Using this method, we should pay attention to the use of references attached to reviews and monographs, because such references are more targeted and more numerous. Taking this as a starting point, a lot of related documents will be found. However, this retrieval method is likely to miss detection. It is suitable for use when there is no retrieval tool or the retrieval tool is incomplete.
Scientific Citation Index (SCI) is a new retrieval tool developed on the basis of retrospective retrieval practice. As long as we know (or find out) the author's name of relevant literature, we can carry out retrospective retrieval, which is a way of citation retrieval and also a retrospective method.
3. Comprehensive method.
Comprehensive method is also called subsection method, circulation method and alternation method. In fact, it is a comprehensive retrieval method that combines ordinary methods and backtracking methods, or a retrieval method that uses the two methods alternately. It is divided into two types:
(1) compound alternating method
Firstly, we use retrieval tools to find some relevant documents, and then take the references attached to these documents as clues to expand the clues and obtain more relevant documents. That is, the first commonly used method and the later retrospective method are used alternately; You can also use the reference attached to a document as a clue, and then use the corresponding retrieval tools to check, expand the clue and trace it down to get the required document. That is, the retrospective method first, the common method later, and the continuous alternate use method.
(2) Interval alternating method
Firstly, a number of useful documents are found by using retrieval tools, and then the reference documents attached to these documents are used for retrospective retrieval to expand the retrieval scope. Because there is a rule in quoting documents, that is, important documents are generally quoted within five years. Therefore, we can skip about 5 years, and then use the retrieval tool to check a number of related documents and conduct follow-up tests again. In this way, the interval is used alternately until the subject retrieval requirements are met. It is suitable for projects that need a long time, which can save time and improve efficiency.
4. Spot check method.
In view of the peak period of the development of a certain discipline or the peak period of the research of a certain discipline, the years in which more documents have been published for several years or more are randomly selected. It takes less time and is efficient, but only if the searcher is familiar with the historical background of the research and development of this subject or topic.
The above retrieval methods are often used by researchers in literature retrieval.