全文获取类型
收费全文 | 8747篇 |
免费 | 890篇 |
国内免费 | 3篇 |
出版年
2023年 | 38篇 |
2022年 | 124篇 |
2021年 | 198篇 |
2020年 | 106篇 |
2019年 | 141篇 |
2018年 | 154篇 |
2017年 | 127篇 |
2016年 | 252篇 |
2015年 | 375篇 |
2014年 | 439篇 |
2013年 | 535篇 |
2012年 | 650篇 |
2011年 | 593篇 |
2010年 | 388篇 |
2009年 | 326篇 |
2008年 | 460篇 |
2007年 | 453篇 |
2006年 | 404篇 |
2005年 | 369篇 |
2004年 | 372篇 |
2003年 | 384篇 |
2002年 | 313篇 |
2001年 | 140篇 |
2000年 | 145篇 |
1999年 | 152篇 |
1998年 | 98篇 |
1997年 | 78篇 |
1996年 | 86篇 |
1995年 | 68篇 |
1994年 | 63篇 |
1993年 | 60篇 |
1992年 | 106篇 |
1991年 | 111篇 |
1990年 | 85篇 |
1989年 | 88篇 |
1988年 | 90篇 |
1987年 | 88篇 |
1986年 | 70篇 |
1985年 | 76篇 |
1984年 | 61篇 |
1983年 | 56篇 |
1982年 | 32篇 |
1979年 | 45篇 |
1978年 | 33篇 |
1976年 | 31篇 |
1975年 | 38篇 |
1974年 | 54篇 |
1973年 | 45篇 |
1972年 | 39篇 |
1968年 | 36篇 |
排序方式: 共有9640条查询结果,搜索用时 15 毫秒
1.
2.
3.
The dose of intravenous diazepam required for sedation was estimated in a series of 78 patients aged 17-85 years given the drug for dental and endoscopic procedures. Multiple regression analysis showed a significant correlation (r = 0.71; p less than 0.001) between dose and age, body weight, the taking of regular sedation, and the taking of more than 40 g alcohol daily, but there were no differences in the doses required between men and women, smokers and non-smokers, inpatients and outpatients, or dental and endoscopy patients. Patients aged 80 required an average dose of 10 mg and patients aged 20 an average dose of 30 mg, and the dose required was much higher in those receiving regular sedation or having a high alcohol intake. Plasma total and free diazepam concentrations were measured in the second half of the series of patients (n = 37). Plasma concentrations required for sedation fell twofold to threefold between the ages of 20 and 80 and were significantly higher in those taking regular sedation or alcohol. Differences in the acute response to diazepam appeared to be due to differences in the sensitivity of the central nervous system (pharmacodynamic tolerance) rather than to differences in pharmacokinetic factors. 相似文献
4.
Sophie J. Milward Natalie Sebanz 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2016,371(1686)
This opinion piece offers a commentary on the four papers that address the theme of the development of self and other understanding with a view to highlighting the important contribution of developmental research to understanding of mechanisms of social cognition. We discuss potential mechanisms linking self–other distinction and empathy, implications for grouping motor, affective and cognitive domains under a single mechanism, applications of these accounts for joint action and finally consider self–other distinction in group versus dyadic settings. 相似文献
5.
6.
7.
Elizabeth M. A. Valleley Christine J. Harrison Yvonne Cook Mark W. J. Ferguson Paul T. Sharpe 《Chromosoma》1994,103(7):502-507
Comparative mapping studies of X-linked genes in mammals have provided insights into the evolution of the X chromosome. Many reptiles including the American alligator, Alligator mississippiensis, do not appear to possess heteromorphic sex chromosomes, and sex is determined by the incubation temperature of the egg during embryonic development. Mapping of homologues of mammalian X-linked genes in reptiles could lead to a greater understanding of the evolution of vertebrate sex chromosomes. One of the genes used in the mammalian mapping studies was ZFX, an X-linked copy of the human ZFY gene which was originally isolated as a candidate for the mammalian testis-determining factor (TDF). ZFX is X-linked in eutherians, but maps to two autosomal locations in marsupials and monotremes, close to other genes associated with the eutherian X. The alligator homologue of the ZFY/ZFX genes, Zfc, has been isolated and described previously. A detailed karyotype of A. mississippiensis is presented, together with chromosomal in situ hybridisation data localising the Zfc gene to chromosome 3. Further chromosomal mapping studies using eutherian X-linked genes may reveal conserved chromosomal regions in the alligator that have become part of the eutherian X chromosome during evolution. 相似文献
8.
9.
10.