全文获取类型
收费全文 | 19460篇 |
免费 | 257篇 |
国内免费 | 121篇 |
专业分类
教育 | 13533篇 |
科学研究 | 2593篇 |
各国文化 | 125篇 |
体育 | 1485篇 |
综合类 | 19篇 |
文化理论 | 186篇 |
信息传播 | 1897篇 |
出版年
2021年 | 135篇 |
2020年 | 225篇 |
2019年 | 350篇 |
2018年 | 521篇 |
2017年 | 517篇 |
2016年 | 599篇 |
2015年 | 387篇 |
2014年 | 414篇 |
2013年 | 2921篇 |
2012年 | 468篇 |
2011年 | 518篇 |
2010年 | 343篇 |
2009年 | 303篇 |
2008年 | 356篇 |
2007年 | 367篇 |
2006年 | 344篇 |
2005年 | 955篇 |
2004年 | 788篇 |
2003年 | 578篇 |
2002年 | 394篇 |
2001年 | 337篇 |
2000年 | 327篇 |
1999年 | 320篇 |
1998年 | 164篇 |
1997年 | 170篇 |
1996年 | 212篇 |
1995年 | 186篇 |
1994年 | 154篇 |
1993年 | 155篇 |
1992年 | 236篇 |
1991年 | 241篇 |
1990年 | 242篇 |
1989年 | 273篇 |
1988年 | 226篇 |
1987年 | 240篇 |
1986年 | 227篇 |
1985年 | 261篇 |
1984年 | 237篇 |
1983年 | 215篇 |
1982年 | 185篇 |
1981年 | 178篇 |
1980年 | 161篇 |
1979年 | 248篇 |
1978年 | 194篇 |
1977年 | 184篇 |
1976年 | 153篇 |
1975年 | 136篇 |
1974年 | 155篇 |
1973年 | 133篇 |
1971年 | 122篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
While archivists in western and eastern Germany may have different traditions, they face the same challenges presented by the use of information technology in government offices in recent years. Documentation strategies and goals in advising agencies must be developed in consideration of current professional debate and limited resources. The following article presents tendencies in governmental records management, advising strategies of archives, and schemes for broad-scale appraisal based on observations at the level of the governments of the German Länder and includes case studies from Saxony. 相似文献
952.
953.
954.
955.
956.
The aim of this study was to investigate, for typical shoes and surfaces used in tennis, the relative role of the shoe and
surface in providing cushioning during running. Five test surfaces ranging from concrete to artificial turf were selected,
together with two shoe models. Impact absorbing ability was assessed mechanically using drop test procedures and biomechanically
using peak magnitude and rate of loading of impact force and peak in-shoe pressure data at the lateral heel. Differences in
biomechanical variables between shoe-surface combinations were identified using a two-way ANOVA (p < 0.05). Mechanical test results were found to rank the surfaces in the same order regardless of the shoe model, suggesting
that the surface is influential in providing cushioning. However, for all mechanical and biomechanical (p < 0.05) variables representing impact absorbing ability, it was found that the difference between shoes was markedly greater
than the differences between surfaces. The peak heel pressure data were found to rank the surfaces in the same order as the
mechanical tests, while impact force data were not as sensitive to the changes in surface. Correlations between mechanical
and biomechanical impact absorption highlighted the importance of testing the shoe-surface combination in mechanical tests,
rather than the surface alone. In conclusion, mechanical testing of the shoe-surface combination was found to provide a strong
predictor of the impact absorbing ability during running if pressure data were used. In addition, for typical shoe-surface
combinations in tennis, the shoe was found to have more potential than the surface to influence impact loading during running.
Finally, in-shoe pressure data were found to be more sensitive than force plate data to changes in material cushioning. 相似文献
957.
A mathematical model relating power output of rower to stroke rate on an ergometer (the Concept II Indoor Rower TM, Model
C) is studied. The model is used to analyse the ergometer performance of a particular rower. It is determined that he can
be more efficient (i.e. decrease power output while maintaining fixed velocity) by decreasing stroke rate, but at the expense
of increasing force during the drive. It is also shown that he can be more efficient by increasing the drag factor (using
higher vent setting) without increasing force. Dependence of power output on rowing style (the shape of the force curve) is
also examined. It is shown that variation of force during the drive has little effect on efficiency, but efficiency is reduced
by asymmetry of the force curve that favours the legs. 相似文献
958.
Fikar CR 《Medical reference services quarterly》2003,22(4):13-19
This paper discusses concepts and terminology of some aspects of the autoimmune and rheumatic disorders as related to medical reference work. Details of anatomic, biochemical, and pathologic processes are not discussed. Knowledge of the specific terminology involved in this area may help to ensure a good approach to developing prudent strategies for database searching of the medical literature and, therefore, is reviewed. MeSH thesaurus terms are shown and textword synonyms are presented that provide tools for thorough searching techniques. Commonly used medical jargon as well as older terminology for this area is also explained. Examples of specific search strategies are illustrated. 相似文献
959.
Bartlett R 《Journal of sports sciences》2001,19(7):467-468
960.