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   15496篇
  免费   1152篇
  国内免费   458篇
耳鼻咽喉   64篇
儿科学   170篇
妇产科学   40篇
基础医学   2900篇
口腔科学   214篇
临床医学   1013篇
内科学   1123篇
皮肤病学   56篇
神经病学   5829篇
特种医学   189篇
外科学   562篇
综合类   1497篇
现状与发展   2篇
一般理论   1篇
预防医学   1096篇
眼科学   88篇
药学   1580篇
  2篇
中国医学   536篇
肿瘤学   144篇
  2024年   36篇
  2023年   198篇
  2022年   333篇
  2021年   530篇
  2020年   423篇
  2019年   510篇
  2018年   460篇
  2017年   493篇
  2016年   514篇
  2015年   496篇
  2014年   799篇
  2013年   1270篇
  2012年   862篇
  2011年   1042篇
  2010年   843篇
  2009年   848篇
  2008年   914篇
  2007年   866篇
  2006年   819篇
  2005年   660篇
  2004年   605篇
  2003年   501篇
  2002年   427篇
  2001年   343篇
  2000年   261篇
  1999年   224篇
  1998年   211篇
  1997年   186篇
  1996年   182篇
  1995年   175篇
  1994年   115篇
  1993年   106篇
  1992年   110篇
  1991年   92篇
  1990年   74篇
  1989年   54篇
  1988年   54篇
  1987年   38篇
  1986年   37篇
  1985年   75篇
  1984年   58篇
  1983年   49篇
  1982年   50篇
  1981年   29篇
  1980年   25篇
  1979年   23篇
  1978年   15篇
  1977年   20篇
  1976年   16篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
d-Amphetamine, 4-OH amphetamine, and epinephrine have been shown in many behavioral studies to facilitate memory when given post-training. The effect of these drugs on the maintained discharge of cells in the locus coeruleus (LC) was investigated using a route of administration (intraperitoneal) and a log-dose range of these drugs comparable to those used in the behavioral experiments.d-Amphetamine profoundly suppressed maintained discharge: an inhibitory effect was observed at every dose (0.1, 1.0, 10.0 mg/kg). In contrast, only the highest dose of 4-OH amphetamine (8.2 mg/kg) inhibited activity in the LC, and this effect was a modest one. Unlike the amphetamines, epinephrine (500 μ/kg) elevated maintained discharge. These results are discussed in the contex of the hypothesized involvement of the LC in the enhancement of memory by these drugs.  相似文献   
52.
肺螨类生境研究   总被引:24,自引:0,他引:24  
本文叙述了肺螨类的孳生环境及其不同生境里肺螨的种群分布,并对分离出的28种螨的生境和肺螨病患者的工作环境进行了对比分析,认为螨在肺螨病患者工作环境中的分布和肺螨的生境基本上相符合,因此证实了患者的病原体是直接来源于工作环境。  相似文献   
53.
Memory function in normal aging   总被引:4,自引:0,他引:4  
Basic findings obtained on memory functions in normal aging are presented and discussed with respect to five separate but interacting memory systems. These systems are: episodic memory, semantic memory, short-term memory, perceptual representation system and procedural memory. All available evidence from cross-sectional research shows that there is a linear, decreasing memory performance as a function of age for episodic memory. Longitudinal studies suggest, however, that this age deficit may be an overestimation, by showing a relatively stable performance level up to middle age, followed by a sharp decline. Studies on semantic memory, short-term memory, perceptual representation system, and procedural memory show a relatively constant performance level across the adult life span, although some tasks used to assess short-term memory and procedural memory have revealed an age deficit. Disregarding the mixed results for these latter two memory systems, it can be concluded that episodic memory is unique in showing an age deficit. Episodic memory is also unique in the sense that it is the only memory system showing gender differences in performance throughout the adult life span with a significantly higher performance for women.  相似文献   
54.
The purpose of this study was to examine motor learning and retention given extensive practice in two fundamentally different movement sequences. One sequence was a memory-driven task (performing a series of whole body positions from memory) and the other a context-driven task (buttoning). Practice took place over 3 weeks, with performance measured weekly; retention was measured weekly for 3 weeks after practice. There were 7 people with Parkinson's disease (PD) and 7 age-matched neurologically healthy people who participated in this study. Both groups improved performance on both tasks with practice, with the majority of the change for the PD group occurring between 1 and 2 weeks of practice. Although those with PD did not necessarily perform as well as age-matched controls, they learned both sequences in a manner similar to age-matched controls, and exhibited retention across the 3-week retention interval. If people with PD are given sufficient practice they can learn and retain both memory-based and context-driven movement sequences as well as age-matched controls. The results provide support for maintaining physical activity and for intervention through movement therapy.  相似文献   
55.
Introduction – Despite the current interest in criteria for vascular dementia, global, as opposed to focal, cognitive change after cerebral infarction has rarely been studied. Material and methods – We documented the neuropsychological changes one to three weeks and three months post infarct in 25 unselected patients with acute, first cerebral infarcts. Results – Improvements were seen in processes thought to have a large subcortical component and in those mediated in the right hemisphere. Memory was relatively lightly affected. Conclusion – The minimal deficits seen in memory and the predominance of subcortical changes are at variance with the currently suggested criteria for vascular dementia. Further data of this kind are needed before firm criteria can be proposed for the global pattern of cognitive changes expected in vascular dementia.  相似文献   
56.
The experiment investigated the effects in healthy volunteers of a single dose of temazepam (30 mg, oral) on effortful and automatic processing, by measuring memory for information and its context. Effortful processing was impaired, as shown by significant impairments in free recall of an 18-item list, but automatic processing was spared, as evidenced by no impairments in recall of the frequency of presentation, the colour, size or form of the items. In a second task, temazepam significantly impaired both recognition and recency memory of 30 items, although these scores were not correlated. Temazepam caused significant sedation, measured by an objective test and by subjective ratings, but this did not correlate with the memory impairments. The pattern of results is discussed with reference to the hypothesis that the memory impairments resulting from benzodiazepines are due to a reduction in information processing resources and thus affect effortful processing more than automatic processing.  相似文献   
57.
15例离退休健康男性老人和9例红细胞增多症男性病人返回平原后,记忆功能改变的特点:①两组受试者除5例成绩下降外,苏州记忆成绩高于西宁成绩(p<0.01)。②记忆成绩降低现象存在于20%左右的人中。③高原缺氧和返平原脱适应均主要影响短时记忆。  相似文献   
58.
目的:探讨西脉镍钛形状记忆合金环抱器用于骨折内固定术有关的护理配合问题。方法:12例不同部位骨折病人(其中男性8例、女性4例、年龄15~62岁)采用西脉镍钛(TiNi)形状记忆合金环抱器人实施内固定手术,观察术中护理配合要点和实际效果。结果:骨折复位满意,手术持续时间<2h。所有病人术后均无感染迹象,手术切口愈合良好。结论:围术期护理配合质量(如器械选择、塑形准备、无菌操作等)的优劣,是手术成功与否的重要因素之一。  相似文献   
59.
An 8-year longitudinal study of elderly people has provided data concerning age-associated impairment (AAMI). In 1985 a random sample of 146 persons aged 65 years or more, living in their own homes, were assessed using the Guild Memory Test the Mini–Mental State Examination (MMSE) and other ratings. After excluding 21% of the sample because they scored less than 24 on the MMSE, and another 34% who fulfilled other exclusion criteria, some 48% of the remainder (22% of the total sample) clearly fulfilled NIMH criteria for AAMI and a further 36% (16% of the total sample) were recorded as forgetful. The NIMH criteria are appropriate for certain research purposes but not in assessing prevalence of memory disorders. Follow–up interviews were conducted after 2, 4, 6 and 8 years. The mortality rate and development of dementia among those fulfilling criteria for AAMI appeared similar to the other non-demented groups of subjects; the mortality rate of those with MMSE scores below 24 was significantly higher. Guild test results at 2-yearly intervals showed considerable changes; half of those scoring least well who were retested showed improvement.  相似文献   
60.
The effects of moclobemide, a new selective and reversible MAO-A inhibitor, on cognitive function and psychomotor performance were measured in 12 healthy elderly male volunteers (with a mean age of 72.5 years). Subjects received moclobemide 200 mg, amitriptyline (positive internal control) 25 mg or placebo twice daily and were assessed on a battery of psychometric tests on the mornings following the first (acute) day and seventh (sub-chronic) day. The tests were: Choice Reaction Time; Tracking; Critical Flicker Fusion Threshold; Memory Scanning; Continuous Attention Task; the Leeds Sleep Evaluation Questionnaire and a Visual Line Analogue Rating Scale. The results show that amitriptyline produced impairment of cognitive and psychomotor functions. Moclobemide, however, did not disrupt sleep or cause daytime sedation, and remained neutral in the assessment of behavioural toxicity.  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