首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   945篇
  免费   92篇
  国内免费   10篇
耳鼻咽喉   2篇
儿科学   42篇
妇产科学   7篇
基础医学   137篇
口腔科学   12篇
临床医学   123篇
内科学   121篇
皮肤病学   6篇
神经病学   119篇
特种医学   178篇
外科学   35篇
综合类   35篇
一般理论   3篇
预防医学   119篇
眼科学   2篇
药学   84篇
  1篇
肿瘤学   21篇
  2022年   7篇
  2021年   15篇
  2020年   6篇
  2019年   14篇
  2018年   15篇
  2017年   13篇
  2016年   13篇
  2015年   15篇
  2014年   19篇
  2013年   29篇
  2012年   38篇
  2011年   40篇
  2010年   18篇
  2009年   19篇
  2008年   37篇
  2007年   42篇
  2006年   45篇
  2005年   23篇
  2004年   29篇
  2003年   22篇
  2002年   29篇
  2001年   28篇
  2000年   33篇
  1999年   27篇
  1998年   30篇
  1997年   22篇
  1996年   34篇
  1995年   21篇
  1994年   28篇
  1993年   25篇
  1992年   18篇
  1991年   23篇
  1990年   20篇
  1989年   25篇
  1988年   20篇
  1987年   30篇
  1986年   18篇
  1985年   20篇
  1984年   15篇
  1983年   20篇
  1982年   14篇
  1981年   12篇
  1980年   11篇
  1979年   8篇
  1977年   13篇
  1976年   10篇
  1970年   3篇
  1966年   5篇
  1961年   3篇
  1960年   3篇
排序方式: 共有1047条查询结果,搜索用时 15 毫秒
1.
2.
3.
Buspirone is a novel agent which is clinically effective as an anxiolytic but which lacks the muscle relaxant, anticonvulsant and sedative effects of classical anxiolytics. It also lacks the full spectrum of action of classical anxiolytics in animal models of anxiety based on shock and novelty. In the present paper the effects of buspirone and chlordiazepoxide were tested on acquisition of differential reinforcement of low rates of response (DRL). This schedule involves the suppression of behaviour by reward omission and has shown consistent effects with classical anxiolytics. Buspirone was tested at doses of 0.3, 1.1 and 3.3 mg/kg i.p. and chlordiazepoxide at 5 and 20 mg/kg. Buspirone produced effects similar to those of chlordiazepoxide on accuracy of DRL responding. However, the size of the observed effects of buspirone was small even in relation to the 5 mg/kg dose of chlordiazepoxide and did not appear to be directly related to dose. Chlordiazepoxide increased overall rate of responding, while buspirone decreased it. Buspirone appears to show only limited conformity with benzodiazepines in animal models of anxiety and this result appears independent of the reinforcer used in the task.  相似文献   
4.
5.
进一步研究了抗三尖杉酯碱的HL-60细胞(HR20)抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明,环孢菌素A(CsA)20,10μg·ml ̄(-1)诱导HL-60细胞发生凋亡,而阻断HR20细胞于G_1期,就不能诱导细胞发生凋亡。低浓度的CsA明显增加柔红霉素在HR20细胞内的积聚,其逆转抗药性作用与阻断细胞周期运行无关。CsA10μg·ml ̄(-1)处理HR20细胞,可引起50kDa的蛋白质高度磷酸化。结果提示:环孢菌素A阻断抗三尖杉酯碱的HL-60细胞于G_1期,而诱导敏感的HL-60细胞发生凋亡,其阻断作用与抗药性无关  相似文献   
6.
We evaluated the relationship between life events, social support, coping, and depression in 27 male inpatients meeting the requirements for Research Diagnostic Criteria major depressive disorder and in 35 age- and sex-matched nonpatients. Overall, the hospitalized depressed patients reported significantly more events and difficulties than did the controls, but this difference in statistical significance disappeared after excluding from analysis "non-independent" happenings which could have been brought on by depression. More hospitalized depressed patients (23 of 27, or 85%) than controls (8 of 35, or 22.9%) experienced markedly threatening events and difficulties ("marked adversities") in the 6 months before their interview. The depressed group also reported having significantly fewer social supports, being less satisfied with the emotional component of this support, and using more emotion-focused coping than the controls. A discriminant analysis predicted depressive status from a combination of marked adversities, reduced number of social supports, and greater use of emotion-focused coping. The results indicate that the relationship of life events to depression is complex. The excess number of events might be partly a product of dysfunctional behavior that "produces" depression-related events which might, in turn, exacerbate depression; simultaneously, patients are more likely to experience highly adverse events which might precipitate the depression in the first place. Reduced social supports and the use of emotion-focused coping appear to also be associated with hospitalization for major depression.  相似文献   
7.
N-methyl-D-aspartate (NMDA) receptor/channel antagonists have previously been shown to impair spatial working memory and hippocampal long-term potentiation. The present experiment investigated the effects of a variety of doses of NMDA antagonists on a working memory task in rats involving an auditory delayed conditional discrimination. Signal detection analysis and an exponential memory decay model were used to extract independent measures of stimulus discriminability and rate of forgetting. A competitive NMDA antagonist, (CPP, 0.33, 1.0, 10.0 mg/kg, IP) produced a reduction in discriminability which was linearly related to log dose, but which was only clear at the 10 mg/kg dose. Rate of forgetting was not increased by any dose. Similar results were obtained with a non-competitive antagonist (MK-801, 0.1, 0.33 mg/kg, IP). These data suggest that doses of NMDA receptor channel antagonists sufficient to disrupt hippocampal long-term potentiation and radial arm maze performance will also disrupt delayed conditional discrimination. The effect on delayed conditional discrimination is due to a disruption of stimulus discriminability and not to an increased rate of forgetting. The extent to which these effects relate to the reported changes in hippocampal long-term potentiation and radial arm maze performance remains to be determined.  相似文献   
8.
Hydrolysis of peptides within lumen of small intestine   总被引:2,自引:0,他引:2  
  相似文献   
9.
10.
Summary The effects of massive destruction of granule cells of the fascia dentata on the spatial and temporal firing characteristics of pyramidal cells in the CA1 and CA3 subfields of the hippocampus were examined in freely moving rats. Microinjections of the neurotoxin colchicine were made at a number of levels along the septo-temporal axis of the dentate gyri of both hemispheres, resulting in destruction of over 75% of the granule cells. By contrast there was relatively little damage to the pyramidal cell fields. As assessed by three different behavioral tests, the colchicine treatment resulted in severe spatial learning deficits. Single units were recorded from the CA1 and CA3 subfields using the stereotrode recording method while the animals performed a forced choice behavioral task on the radial 8-arm maze. Considering the extent of damage to the dentate gyrus, which has hitherto been considered to be the main source of afferent information to the CA fields, there was remarkably little effect on the spatial selectivity of place cell discharge on the maze, as compared to recordings from control animals. There was, however, a change in the temporal firing characteristics of these cells, which was manifested primarily as an increase in the likelihood of burst discharge. The main conclusion derived from these findings is that most of the spatial information exhibited by hippocampal pyramidal cells is likely to be transmitted from the cortex by routes other than the traditional trisynaptic circuit. These routes may include the direct projections from entorhinal layers II and III to CA3 and CA1, respectively.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号