全文获取类型
收费全文 | 22491篇 |
免费 | 396篇 |
国内免费 | 30篇 |
专业分类
教育 | 16229篇 |
科学研究 | 1986篇 |
各国文化 | 204篇 |
体育 | 1713篇 |
综合类 | 34篇 |
文化理论 | 189篇 |
信息传播 | 2562篇 |
出版年
2022年 | 132篇 |
2021年 | 229篇 |
2020年 | 363篇 |
2019年 | 491篇 |
2018年 | 699篇 |
2017年 | 773篇 |
2016年 | 716篇 |
2015年 | 429篇 |
2014年 | 576篇 |
2013年 | 4256篇 |
2012年 | 566篇 |
2011年 | 630篇 |
2010年 | 481篇 |
2009年 | 457篇 |
2008年 | 520篇 |
2007年 | 500篇 |
2006年 | 442篇 |
2005年 | 385篇 |
2004年 | 365篇 |
2003年 | 327篇 |
2002年 | 379篇 |
2001年 | 425篇 |
2000年 | 397篇 |
1999年 | 403篇 |
1998年 | 210篇 |
1997年 | 232篇 |
1996年 | 255篇 |
1995年 | 213篇 |
1994年 | 210篇 |
1993年 | 193篇 |
1992年 | 302篇 |
1991年 | 301篇 |
1990年 | 330篇 |
1989年 | 311篇 |
1988年 | 295篇 |
1987年 | 248篇 |
1986年 | 256篇 |
1985年 | 322篇 |
1984年 | 266篇 |
1983年 | 255篇 |
1982年 | 196篇 |
1981年 | 206篇 |
1980年 | 176篇 |
1979年 | 240篇 |
1978年 | 215篇 |
1977年 | 194篇 |
1976年 | 160篇 |
1975年 | 128篇 |
1974年 | 120篇 |
1973年 | 147篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Jennifer R. Warren Michael L. Hecht David A. Wagstaff Elvira Elek Khadidiatou Ndiaye Patricia Dustman Flavio F. Marsiglia 《Journal of Applied Communication Research》2006,34(2):209-227
This study sought to determine if exposure to two communication-oriented activities, videotapes and public service announcements, accounts for changes in substance use among adolescents participating in the Drug Resistance Strategies Project's keepin' it REAL adolescent substance use prevention curriculum. Middle-school students (4,734, 72% Latino) responded to questionnaires related to these analyses. An analysis of covariance (ANCOVA) model was fit separately to six substance use outcomes. The results suggested that intervention students who saw four or five videos engaged in less substance use in the past month than did students who saw fewer videos. Having seen the PSAs one or more times did not predict the reported change in substance use. 相似文献
92.
Danuta A. Nitecki 《Archival Science》2004,4(1-2):17-44
Evaluators of library programs have different perspectives on why to conduct an evaluation and also how to do so. The author
suggests that a minimal approach to conducting a library program evaluation is to prove that the program exists. But this
perspective has expanded to include different degrees of interest in the client and operations, culminating in a combined
focus that leads evaluators to conduct outcome assessments. The chapter includes speculation on what motivates managers to
undertake an evaluation, a review of some ways that library evaluations are conducted, and a discussion of several examples
of program evaluations. Though there are not single directives for undertaking a library program evaluation, there are a variety
of tools and advice to entice librarians to do more of them as a way to improve understanding the value of a library to its
clientele and in society. 相似文献
93.
E Diane Johnson Paul E Pancoast Joyce A Mitchell Chi-Ren Shyu 《Journal of the Medical Library Association》2004,92(4):438-444
PURPOSE: This study describes the system architecture and user acceptance of a suite of programs that deliver information about newly updated library resources to clinicians' personal digital assistants (PDAs). DESCRIPTION: Participants received headlines delivered to their PDAs alerting them to new books, National Guideline Clearinghouse guidelines, Cochrane Reviews, and National Institutes of Health (NIH) Clinical Alerts, as well as updated content in UpToDate, Harrison's Online, Scientific American Medicine, and Clinical Evidence. Participants could request additional information for any of the headlines, and the information was delivered via e-mail during their next synchronization. Participants completed a survey at the conclusion of the study to gauge their opinions about the service. RESULTS/OUTCOME: Of the 816 headlines delivered to the 16 study participants' PDAs during the project, Scientific American Medicine generated the highest proportion of headline requests at 35%. Most users of the PDA Alerts software reported that they learned about new medical developments sooner than they otherwise would have, and half reported that they learned about developments that they would not have heard about at all. While some users liked the PDA platform for receiving headlines, it seemed that a Web database that allowed tailored searches and alerts could be configured to satisfy both PDA-oriented and e-mail-oriented users. 相似文献
94.
95.
Sarah Anne Murphy Martha A Bedard Jill Crawley-Low Diane Fagen Jean-Paul Jette 《Journal of the Medical Library Association》2005,93(1):130-132
The Standards Committee of the Veterinary Medical Libraries Section was appointed in May 2000 and charged to create standards for the ideal academic veterinary medical library, written from the perspective of veterinary medical librarians. The resulting Standards for the Academic Veterinary Medical Library were approved by members of the Veterinary Medical Libraries Section during MLA '03 in San Diego, California. The standards were approved by Section Council in April 2005 and received final approval from the Board of Directors of the Medical Library Association during MLA '04 in Washington, DC. 相似文献
96.
Linda M Hartman Rebecca A Abromitis Alice B Kuller Barbara A Epstein 《Journal of the Medical Library Association》2005,93(2):271-277
OBJECTIVE: A staff development committee (SDC) was convened to implement staff development opportunities for an academic health sciences library system comprised of three separate facilities. The charge for the SDC was to: (1) develop programs to enhance workplace skills and personal growth, (2) communicate the availability of existing programs at the university and medical center, and (3) encourage the staff to participate in these opportunities. PROGRAM: The committee created goals and objectives and developed a survey designed to give staff the opportunity to provide input for this initiative. With an 80% response rate, the survey results were used to plan 15 events based on staff needs and preferences. First-year attendance for SDC-sponsored events was 459. Committee members served as liaisons for each event. Two forms were developed to facilitate event planning. A monthly announcement sheet, email reminders, and the library's local area network are used to communicate upcoming SDC events and encourage attendance. CONCLUSION: This approach can serve as a useful model for similar program planning in any organization. 相似文献
97.
98.
Black-dyed artefacts are found in museums worldwide, many produced using an iron-tannate compound. Deterioration of iron-tannate dyed artefacts is an international preservation issue: in New Zealand the deterioration of paru (iron-tannate) dyed Māori textiles is widespread. This article reports experimental work testing the efficacy of sodium alginate, a consolidant developed for deteriorated paru-dyed muka (fibre from harakeke; Phormium tenax). The colour stability, strength retention, and acidity of paru-dyed muka consolidated with sodium alginate (0.25, 0.5, and 1% w/v in water) was tested pre- and post-artificial light ageing. This study found that sodium alginate had no negative effect on paru-dyed muka and in some cases provided benefit. Interestingly, the colour of paru-dyed muka is substantially more stable in UV-filtered light than previously recognised. Also microfading results were in agreement with visual assessments of colour change at 1 Mlux hour exposure, providing confidence in this relatively new technique to assess colour change. 相似文献
99.
Bast fibres have been commonly used as a textile material in Northern Europe since Neolithic times. However, the process of identifying the different species has been problematic, and many important questions related to their cultural history are still unanswered. For example, a modified Herzog test and the presence of calcium oxalate crystals have both been used in identification. In order to generate more reliable results, further research and advancement in multi-methodological methods is required. This paper introduces a combination of methods which can be used to identify and distinguish flax (Linum usitatissimum), hemp (Cannabis sativa), and stinging nettle (Urtica dioica). The research material consisted of reference fibres and 25 fibre samples obtained from 12 textiles assumed to be made of nettle. The textiles were from the Finno-Ugric and Historical Collections of The National Museum of Finland. The fibre samples were studied by observing the surface characteristics and cross sections with transmitted light microscopy, and by using a modified Herzog test with polarized light, in order to identify the distinguishable features in their morphological structures. The study showed that five out of 25 samples were cotton, 16 nettle, one flax, and one hemp. Findings from two samples were inconsistent. The results show that it is possible to distinguish common north European bast fibres from each other by using a combination of microscopic methods. Furthermore, by utilizing these combined methods, new and more reliable information could be obtained from historical ethnographic textiles, which creates new vistas for the interpretation of their cultural history. 相似文献
100.
This paper analyses the publication patterns of researchers in the field of applied sciences at Universities of Technology in South Africa. Aspects investigated include publications in SCOPUS-listed journals; number of citations and countries of publication. Collaborative research patterns at national and international levels were also investigated. A bibliometric analysis approach was followed using SCOPUS as the main source of data and analysing the articles published in selected applied science disciplines. Results show that researchers in the field of applied sciences in universities of technology have increased their number of publications over the past 10?years and are also working in conjunction with other researchers both nationally and internationally. The analysis is an important addition to the field in South Africa which helps in measuring how institutions are positively responding to government incentives in research. The results are also important to information professionals who are increasingly playing an important role in research impact assessments. 相似文献