搜索引擎的性能评价

在信息飞速增长的网络环境下，对有用信息的查找变得越来越困难，搜索引擎便应运而生，并逐渐发展壮大。论文以用户为导向构建层次分析模型，借此对搜索引擎的评价作简要探讨。     

The mini MEDLINE SYSTEM: a library-based end-user search system

The mini MEDLINE SYSTEM, a user-friendly search system developed in 1981 at the Georgetown University Medical Center, has been operational since 1982. The system is designed to meet the immediate educational and clinical information needs of students, residents, and faculty. This article focuses on system planning and design, database creation through "downloading," hardware adaptation, and system use. The database is a subset of the NLM's MEDLINE file; it includes over 180,000 citations to articles indexed in over 160 journals from 1982 to the present. With only a few keystrokes in a two-step process it allows users to conduct bibliographic searches. The system is being replicated at eight other medical libraries.     

垂直搜索引擎发展概述

本文分析了垂直搜索引擎的产生，与水平搜索引擎的区别所在，数据来源，盈利模式以及发展方向。     

Evaluation of a program to teach health professionals to search MEDLINE

This study analyzes the search behavior of end users who had taken a class in searching MEDLINE on the National Library of Medicine's MEDLARS system. Of the class alumni, 58% obtained passwords. Most of these were still conducting their own searches twelve to eighteen months later. Telephone interviews and search observations indicated that these end users were satisfied with their results and felt they had mastered the basic mechanics of searching. However, appropriate use of explodes and subheadings, as well as locating appropriate search terms, still presented difficulties for them. Further training in these areas may be required.     

国外博客搜索引擎的比较研究

介绍了国外著名博客搜索引擎的基本特征,并结合检索举例,从覆盖范围、可靠性方面进行了比较和分析,揭示它们各自的优点与不足。     

当前搜索引擎不足及改进建议

搜索引擎已经成为人们获取信息的一个重要手段，对搜索引擎技术的研究也日益增多，如何能有效弥补现有技术的缺陷，更合理地满足用户需求变化越来越重要。本文从信息时效性方面提出对现有“超链分析”技术改进的必要性，并结合现有的过分优化网站行为和结果输出方式进一步提出了改进策略。     

The performance of adverse effects search filters in MEDLINE and EMBASE

Background: Search filters can potentially improve the efficiency of searches involving electronic databases such as medline and embase . Although search filters have been developed for identifying records that contain adverse effects data, little is known about the sensitivity of such filters. Objectives: This study measured the sensitivity of using available adverse effects filters to retrieve papers with adverse effects data. Methods: A total of 233 included studies from 26 systematic reviews of adverse effects were used for analysis. Search filters from medline and embase were tested for their sensitivity in retrieving the records included in these reviews. In addition, the sensitivity of each individual search term used in at least one search filter was measured. Results: Subheadings proved the most useful search terms in both medline and embase . No indexing terms in medline achieved over 12% sensitivity. The sensitivity of published search filters varied in medline from 3% to 93% and in embase from 57% to 97%. Whether this level of sensitivity is acceptable will be dependent on the purpose of the search. Conclusions: Although no adverse effects search filter captured all the relevant records, high sensitivity could be achieved. Search filters may therefore be useful in retrieving adverse effects data.     

MELVYL MEDLINE: reference service implications of an end-user search system.

The implementation of MELVYL MEDLINE, a successful online end-user system in the University of California (UC) health sciences libraries greatly enhanced the capabilities of reference desk service by providing immediate access to current medical literature from the MEDLINE database. With these enhancements, the extent of the impact on the delivery of reference service was not anticipated. Concurrent with providing traditional reference service requests, there was a constant need for individualized end-user instruction by MELVYL MEDLINE users, and continual maintenance of workstation equipment and supplies. This paper describes the experiences at the UC Irvine (UCI) Biomedical Library and compares these experiences with other UC health sciences libraries. The purpose of this paper is to discuss some of the issues which must be considered when planning for the implementation of an end-user system within the reference service function.     

国外四个著名网络搜索引擎的比较研究

对国外四个名的搜索引擎Altaryista、Excite、Infoseek、Yahoo的检索功能、检索特性、检索范围和选项进行了比较和分析，并指出它们各自的优点与不足。     

Developing efficient search strategies to identify reports of adverse effects in MEDLINE and EMBASE

OBJECTIVE: This study aimed to assess the performance, in terms of sensitivity and precision, of different approaches to searching MEDLINE and EMBASE to identify studies of adverse effects. METHODS: Five approaches to searching for adverse effects evidence were identified: approach 1, using specified adverse effects; approach 2, using subheadings/qualifiers; approach 3, using text words; approach 4, using indexing terms; approach 5, searching for specific study designs. The sensitivity and precision of these five approaches, and combinations of these approaches, were compared in a case study using a systematic review of the adverse effects of seven anti-epileptic drugs. RESULTS: The most sensitive search strategy in MEDLINE (97.0%) required a combination of terms for specified adverse effects, floating subheadings, and text words for 'adverse effects'. In EMBASE, a combination of terms for specified adverse effects and text words for 'adverse effects' provided the most sensitive search strategy (98.6%). Both these search strategies yielded low precision (2.8%). CONCLUSIONS: A highly sensitive search in either database requires a combination of approaches, and has low precision. This suggests that better reporting and indexing of adverse effects is required and that an effective generic search filter may not yet be feasible.     

Designing a search strategy to identify and retrieve articles onevidence-based health care using MEDLINE

Thepractice of evidence-based health care requires that information on methodology be identifiedfrom databases such as MEDLINE. Up until this year there have been no designated medicalsubject headings (MeSH) for evidence-based health care. ‘EVIDENCE-BASEDMEDICINE’ appears as a MeSH term from 1997. The absence of designated MeSH forthis concept prior to 1997 provides a challenge to the searcher. This paper describes the creationof a MEDLINE search strategy to retrieve articles on the methods of evidence-based health carepublished prior to the introduction of the new term, where an optimal combination of free-textand MeSH terms is required to identify relevant material. The study examines both free-text andsubject heading searching and attempts an optimal balance of sensitivity and specificity. It beginsby examining separate free-text and subject heading searches. Sensitivity of the subject headingsearch was 33% and specificity 80%, while the free-text search produced asensitivity of 50% and a specificity of 67%. The final strategy, combining bothapproaches, was more successful with sensitivity reaching between 82 and 90% andspecificity 83%. It is therefore possible to devise a search strategy to retrieve articles on themethods of evidence-based health care with relatively successful rates of sensitivity andspecificity. The limitations of MEDLINE, however, necessitate the use of additional approachesin identifying articles on the methods of evidence-based health care.     

A study of medical and health queries to web search engines

This paper reports findings from an analysis of medical or health queries to different web search engines. We report results: (i). comparing samples of 10000 web queries taken randomly from 1.2 million query logs from the AlltheWeb.com and Excite.com commercial web search engines in 2001 for medical or health queries, (ii). comparing the 2001 findings from Excite and AlltheWeb.com users with results from a previous analysis of medical and health related queries from the Excite Web search engine for 1997 and 1999, and (iii). medical or health advice-seeking queries beginning with the word 'should'. Findings suggest: (i). a small percentage of web queries are medical or health related, (ii). the top five categories of medical or health queries were: general health, weight issues, reproductive health and puberty, pregnancy/obstetrics, and human relationships, and (iii). over time, the medical and health queries may have declined as a proportion of all web queries, as the use of specialized medical/health websites and e-commerce-related queries has increased. Findings provide insights into medical and health-related web querying and suggests some implications for the use of the general web search engines when seeking medical/health information.     

基于元搜索引擎跨库检索中检索协议标准比较研究

基于元搜索引擎的跨库检索可以检索到通用搜索引擎检索不到的网络数据库资源，但必须解决元搜索引擎与数据库独立搜索引擎间通信的协议标准问题。本文对目前这方面主要的三种通信协议标准OpenSearch，SRU和MXG进行了比较研究，以便为基于元搜索引擎跨库检索研究的发展提供一些有益的参考。     

Retrieval comparison of EndNote to search MEDLINE (Ovid and PubMed) versus searching them directly

Using EndNote version 7.0, the authors tested the search capabilities of the EndNote search engine for retrieving citations from MEDLINE for importation into EndNote, a citation management software package. Ovid MEDLINE and PubMed were selected for the comparison. Several searches were performed on Ovid MEDLINE and PubMed using EndNote as the search engine, and the same searches were run on both Ovid and PubMed directly. Findings indicate that it is preferable to search MEDLINE directly rather than using EndNote. The publishers of EndNote do warn its users about the limitations of their product as a search engine when searching external databases. In this article, the limitations of EndNote as a search engine for searching MEDLINE were explored as related to MeSH, non-MeSH, citation verification, and author searching.     

Free MEDLINE and implications for library operations

The widespread availability of free MEDLINE systems on the Internet raises issues about the continued need to allocate library funds for commercial, fee-for-service MEDLINE vendors. This paper explores the evolution and acceptance of free MEDLINE, looking in particular at NLM's PubMed system. Results of a survey on librarian perceptions of PubMed are discussed. The new generation of PubMed software is evaluated in the context of end-user needs and educational goals of medical libraries.     

网络搜索引擎研究综述(1994～2004年)

从搜索引擎的定义、分类、工作原理、检索功能、评价标准、涉及的知识产权问题等方面综述了网络搜索引擎研究和开发应用所取得的新进展。