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   195228篇
  免费   2632篇
  国内免费   49篇
耳鼻咽喉   1241篇
儿科学   7436篇
妇产科学   3698篇
基础医学   19356篇
口腔科学   1844篇
临床医学   15124篇
内科学   34230篇
皮肤病学   936篇
神经病学   18861篇
特种医学   9184篇
外科学   30324篇
综合类   2565篇
一般理论   46篇
预防医学   20841篇
眼科学   3108篇
药学   10805篇
中国医学   651篇
肿瘤学   17659篇
  2023年   215篇
  2022年   244篇
  2021年   476篇
  2020年   352篇
  2019年   554篇
  2018年   22423篇
  2017年   17764篇
  2016年   19906篇
  2015年   1409篇
  2014年   1546篇
  2013年   1821篇
  2012年   8449篇
  2011年   22507篇
  2010年   19567篇
  2009年   12291篇
  2008年   20696篇
  2007年   23030篇
  2006年   1932篇
  2005年   3457篇
  2004年   4642篇
  2003年   5491篇
  2002年   3556篇
  2001年   424篇
  2000年   522篇
  1999年   307篇
  1998年   422篇
  1997年   391篇
  1996年   229篇
  1995年   233篇
  1994年   200篇
  1993年   186篇
  1992年   123篇
  1991年   165篇
  1990年   193篇
  1989年   140篇
  1988年   107篇
  1987年   94篇
  1986年   71篇
  1985年   87篇
  1984年   80篇
  1983年   92篇
  1982年   102篇
  1981年   67篇
  1980年   111篇
  1979年   51篇
  1978年   51篇
  1976年   54篇
  1974年   60篇
  1938年   62篇
  1932年   63篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
Background: Both pain and the pharmacologic management of pain can cause the undesirable effect of sleep disruption. One goal of basic and clinical neuroscience is to facilitate rational drug development by identifying the brain regions and neurochemical modulators of sleep and pain. Adenosine is thought to be an endogenous sleep promoting substance and adenosinergic compounds can contribute to pain management. In the pontine brain stem adenosine promotes sleep but the effects of pontine adenosine on pain have not been studied. This study tested the hypothesis that an adenosine agonist would cause antinociception when microinjected into pontine reticular formation regions that regulate sleep.

Methods: The tail flick latency (TFL) test quantified the time in seconds for an animal to move its tail away from a thermal stimulus created by a beam of light. TFL measures were used to evaluate the antinociceptive effects of the adenosine A1 receptor agonist N6-p-sulfophenyladenosine (SPA). Pontine microinjection of SPA (0.1 [mu]g/0.25 [mu]l, 0.88 mm) was followed by TFL measures as a function of time after drug delivery and across the sleep-wake cycle.

Results: Compared with saline (control), pontine administration of the adenosine agonist significantly increased latency to tail withdrawal (P < 0.0001). The increase in antinociceptive behavior evoked by the adenosine agonist SPA was blocked by pretreatment with the adenosine A1 receptor antagonist 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX, 0.75 ng/0.25 [mu]l, 10 [mu]m).  相似文献   

15.
The treatment of deep cartilage defects in load-bearing joints is a problem that still has no satisfactory solution. Full-thickness defects of the articular cartilage rarely heal spontaneously, usually leaving damage that can lead to early arthrosis. Techniques currently available for the treatment of chondral defects include abrasion, drilling, micro-fracturing, transplantation of tissue autografts and allografts, and cell transplantation. Osteochondral autograft transplantation is currently the only surgical cartilage repair technique known to lead to the formation of genuine hyaline articular cartilage and its retention at least in the medium term. The Draenert method, in which a water-cooled diamond bone-cutting system is used, is an effective procedure for resurfacing the joints affected by localised cartilaginous defects, even when there is also severe bone loss. Donor-side morbidity can be kept to a minimum by filling the defect caused by harvesting with a press-fit cylinder of cancellous bone covered with periosteum for protection.  相似文献   
16.
Central post stroke pain is often difficult to manage satisfactorily with conventional treatment modalities for pain. In the last decade functional neurosurgery has offered hope with motor cortex stimulation achieving significant alleviation of pain in some patients. Unfortunately this has led to the neglect of chronic stimulation of deep grey matter as another modality of treating this condition. In this article we present our experience with motor cortex stimulation and that with deep grey matter stimulation in patients with post stroke pain. We argue that both modalities have a significant role and that what is required are better methods of identifying particular patients who are more likely to respond to one or the other.  相似文献   
17.
Contemporary discourse contains numerous examples of use of the concept of culture by social and behavioral scientists. Simple reification, where the speaker makes culture into a thing capable of action exemplifies one usage in public discourse. Some quantitative social scientists attempt to characterize people’s cultural identities by means of a single categorical variable, which often “lumps” people into categories such as “Hispanic” or “Black” that in fact have numerous culturally bounded subcategories. Approaches that emphasize cultural process are preferable to those who attempt to categorize; more complex measures of acculturation help investigators to make convincing analyses of circumstances in which health disparities occur. Examples in which investigators make appropriate use of cultural characterizations demonstrate their utility in investigating health disparities in Haitian American women, injecting and noninjecting drug users, Hispanic youth, and adult Hispanics at risk of HIV infection. Focus on culture in the study of health disparities can identify entanglements between structural factors such as poverty and lack of education and cultural factors such as beliefs about health. Qualitative methods coupled with quantitative methods have great potential to improve investigators’ grasp of cultural nuance while capturing the distribution of qualitatively derived behaviors.  相似文献   
18.
19.
20.
The specific characteristics of genetic data lead to ethical-legal conflicts in the framework of genetic diagnosis. Several international organisations, including UNESCO and the Council of Europe, have enacted rules referring to the use of genetic information. This paper discusses possible legal and ethical criteria that could be used in genetic testing.  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