全文获取类型
收费全文 | 54161篇 |
免费 | 2235篇 |
国内免费 | 30篇 |
专业分类
56426篇 |
出版年
2020年 | 667篇 |
2019年 | 837篇 |
2018年 | 1196篇 |
2017年 | 1183篇 |
2016年 | 1226篇 |
2015年 | 832篇 |
2014年 | 1005篇 |
2013年 | 4765篇 |
2012年 | 1790篇 |
2011年 | 1942篇 |
2010年 | 1117篇 |
2009年 | 1159篇 |
2008年 | 1727篇 |
2007年 | 1704篇 |
2006年 | 1492篇 |
2005年 | 1345篇 |
2004年 | 1317篇 |
2003年 | 1182篇 |
2002年 | 1227篇 |
2001年 | 1769篇 |
2000年 | 1662篇 |
1999年 | 1282篇 |
1998年 | 680篇 |
1997年 | 579篇 |
1996年 | 521篇 |
1995年 | 525篇 |
1994年 | 503篇 |
1993年 | 522篇 |
1992年 | 1014篇 |
1991年 | 960篇 |
1990年 | 946篇 |
1989年 | 857篇 |
1988年 | 817篇 |
1987年 | 805篇 |
1986年 | 812篇 |
1985年 | 857篇 |
1984年 | 671篇 |
1983年 | 579篇 |
1982年 | 477篇 |
1979年 | 656篇 |
1978年 | 487篇 |
1976年 | 450篇 |
1975年 | 591篇 |
1974年 | 621篇 |
1973年 | 594篇 |
1972年 | 541篇 |
1971年 | 473篇 |
1968年 | 540篇 |
1967年 | 540篇 |
1966年 | 475篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
Michael D. Gliksman M.P.H. F.A.C.O.M. Allan Kellehear Ph.D. 《Journal of Near-Death Studies》1990,9(1):41-43
Although cerebral anoxia is not thought to be responsible for triggering near-death experiences (NDEs), the issue is not so clear in the case of hypercapnia. Detection of normal blood gases in Michael Sabom's (1982) case study seems to be the major reply to suggestions that hypercapnia may have a causal role in NDEs. We argue, however, that routine arterial measures of blood gases are not a reliable indicator of cerebral levels. 相似文献
902.
The authors present an introductory overview of the history of near-death phenomena, followed by a synopsis of near-death research representative of three historical eras: 1880s–1930; 1930s–1960; and 1960 to the present. 相似文献
903.
K. Blokker S. Bruin J. Bryden I. Houseman C. Okkerse C. Van der Meer A. P. Verkaik 《Knowledge, Technology, and Policy》1990,3(3):76-83
In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS).
Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as
cooperative unions and multinational companies are included. After considering the influence of the changing environment on
the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined.
Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and
what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences
with this strategic investment are evaluated. 相似文献
904.
905.
906.
The statistical simulation program DATASIM is designed to conduct large-scale sampling experiments on microcomputers. Monte Carlo procedures are used to investigate the Type I and Type II error rates for statistical tests when one or more assumptions are systematically violated-assumptions, for example, regarding normality, homogeneity of variance or covariance, mini-mum expected cell frequencies, and the like. In the present paper, we report several initial tests of the data-generating algorithms employed by DATASIM. The results indicate that the uniform and standard normal deviate generators perform satisfactorily. Furthermore, Kolmogorov-Smirnov tests show that the sampling distributions ofz, t, F, χ2, andr generated by DATASIM simulations follow the appropriate theoretical distributions. Finally, estimates of Type I error rates obtained by DATASIM under various patterns of violations of assumptions are in close agreement with the results of previous analytical and empirical studies; These converging lines of evidence suggest that DATASIM may well prove to be a reliable and productive tool for conducting statistical simulation research. 相似文献
907.
Hardware and software modifications are presented that allow for collection and recognition by a Commodore computer of spoken responses. Responses are timed with millisecond accuracy and automatically analyzed and scored. Accuracy data for this device from several experiments are presented. Potential applications and suggestions for improving recognition accuracy are also discussed. 相似文献
908.
909.
Ronald A. Rensink 《Behavior research methods》1990,22(2):105-117
Pascal routines are described for several real-time operations on Macintosh computers. Methods are presented for millisecond timing and for high-speed transfer of arbitrary bit-image displays to the screen. All routines are based on Toolbox procedures available on virtually all Macintosh computers. 相似文献
910.
The effects of usage of eight verbal response modes by trainee counsellors during an initial interview were determined by reference to client-perceived rapport. Data on rapport were gathered via a standardized client's minute-by-minute ratings of his experience of rapport on a five-point scale during the interview. A total of ten counselling interviews were conducted, and data were examinedfor overall effects (i.e. during the interview as a whole) and minute-by-minute effects. Restatements, Minimal Encouragers and Verbosity were significantly dafferent in occurrence in high versus low rated interviews. Minute-by-minute data revealed that these overall differences were not consistent at all stages of the interviews. Implications for counsellor training are discussed. 相似文献