全文获取类型
收费全文 | 71834篇 |
免费 | 4876篇 |
国内免费 | 201篇 |
专业分类
耳鼻咽喉 | 529篇 |
儿科学 | 2094篇 |
妇产科学 | 1167篇 |
基础医学 | 9850篇 |
口腔科学 | 1506篇 |
临床医学 | 7530篇 |
内科学 | 15241篇 |
皮肤病学 | 984篇 |
神经病学 | 6825篇 |
特种医学 | 2228篇 |
外国民族医学 | 1篇 |
外科学 | 10076篇 |
综合类 | 878篇 |
一般理论 | 72篇 |
预防医学 | 6400篇 |
眼科学 | 1737篇 |
药学 | 4909篇 |
1篇 | |
中国医学 | 80篇 |
肿瘤学 | 4803篇 |
出版年
2023年 | 377篇 |
2022年 | 528篇 |
2021年 | 1399篇 |
2020年 | 841篇 |
2019年 | 1365篇 |
2018年 | 1662篇 |
2017年 | 1238篇 |
2016年 | 1357篇 |
2015年 | 1589篇 |
2014年 | 2377篇 |
2013年 | 3214篇 |
2012年 | 5241篇 |
2011年 | 5369篇 |
2010年 | 3006篇 |
2009年 | 2670篇 |
2008年 | 4880篇 |
2007年 | 5338篇 |
2006年 | 5241篇 |
2005年 | 4974篇 |
2004年 | 4769篇 |
2003年 | 4312篇 |
2002年 | 4204篇 |
2001年 | 576篇 |
2000年 | 405篇 |
1999年 | 635篇 |
1998年 | 899篇 |
1997年 | 754篇 |
1996年 | 635篇 |
1995年 | 605篇 |
1994年 | 490篇 |
1993年 | 464篇 |
1992年 | 350篇 |
1991年 | 307篇 |
1990年 | 256篇 |
1989年 | 247篇 |
1988年 | 264篇 |
1987年 | 215篇 |
1986年 | 233篇 |
1985年 | 246篇 |
1984年 | 308篇 |
1983年 | 326篇 |
1982年 | 384篇 |
1981年 | 369篇 |
1980年 | 344篇 |
1979年 | 197篇 |
1978年 | 239篇 |
1977年 | 191篇 |
1976年 | 133篇 |
1975年 | 102篇 |
1974年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
Scalp electrical recording during paralysis: quantitative evidence that EEG frequencies above 20 Hz are contaminated by EMG. 总被引:2,自引:0,他引:2
Emma M Whitham Kenneth J Pope Sean P Fitzgibbon Trent Lewis C Richard Clark Stephen Loveless Marita Broberg Angus Wallace Dylan DeLosAngeles Peter Lillie Andrew Hardy Rik Fronsko Alyson Pulbrook John O Willoughby 《Clinical neurophysiology》2007,118(8):1877-1888
OBJECTIVE: To identify the possible contribution of electromyogram (EMG) to scalp electroencephalogram (EEG) rhythms at rest and induced or evoked by cognitive tasks. METHODS: Scalp EEG recordings were made on two subjects in presence and absence of complete neuromuscular blockade, sparing the dominant arm. The subjects undertook cognitive tasks in both states to allow direct comparison of electrical recordings. RESULTS: EEG rhythms in the paralysed state differed significantly compared with the unparalysed state, with 10- to 200-fold differences in the power of frequencies above 20 Hz during paralysis. CONCLUSIONS: Most of the scalp EEG recording above 20 Hz is of EMG origin. Previous studies measuring gamma EEG need to be re-evaluated. SIGNIFICANCE: This has a significant impact on measurements of gamma rhythms from the scalp EEG in unparalysed humans. It is to be hoped that signal separation methods will be able to rectify this situation. 相似文献
25.
26.
27.
Biostatisticians have frequently uncritically accepted the measurements provided by their medical colleagues engaged in clinical research. Such measures often involve considerable loss of information. Particularly, unfortunate is the widespread use of the so‐called ‘responder analysis’, which may involve not only a loss of information through dichotomization, but also extravagant and unjustified causal inference regarding individual treatment effects at the patient level, and, increasingly, the use of the so‐called number needed to treat scale of measurement. Other problems involve inefficient use of baseline measurements, the use of covariates measured after the start of treatment, the interpretation of titrations and composite response measures. Many of these bad practices are becoming enshrined in the regulatory guidance to the pharmaceutical industry. We consider the losses involved in inappropriate measures and suggest that statisticians should pay more attention to this aspect of their work. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
28.
29.
30.
Ruth McDonald BA MSc PhD Stephen Harrison BSc MPhil PhD 《Health & social care in the community》2004,12(3):194-201
Recent New Labour policy for the ‘modernisation’ of Government places a good deal of emphasis on decentralisation. This emphasis is particularly marked in relation to the organisation of primary care. However, like hospitals and other National Health Service institutions, primary care trusts (PCTs) are subject to a substantial raft of centrally established performance targets and indicators, including those which contribute to the public award of between zero and three performance ‘stars’. This raises questions about the extent to which employees can exercise autonomy in the context of rigid top‐down directives. This paper presents findings from a study using participant observation and interviews to examine the impact of a training course aimed ostensibly at increasing employee autonomy in an English PCT. The suggestion is that attempts to make employees more autonomous can be seen as a strategy for increasing central control based upon the internalisation by the employees of centrally promulgated values. The attraction of such strategies is that they may be potentially more effective and less costly than alternative strategies of direct control. However, the study suggests that the outcome of attempts by such methods as programmes to increase employee autonomy may be very different from those intended. 相似文献