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   26959篇
  免费   2759篇
  国内免费   38篇
耳鼻咽喉   327篇
儿科学   828篇
妇产科学   514篇
基础医学   3588篇
口腔科学   545篇
临床医学   3211篇
内科学   4715篇
皮肤病学   267篇
神经病学   2879篇
特种医学   989篇
外科学   4214篇
综合类   675篇
一般理论   5篇
预防医学   2976篇
眼科学   525篇
药学   1681篇
中国医学   12篇
肿瘤学   1805篇
  2021年   356篇
  2020年   216篇
  2019年   397篇
  2018年   492篇
  2017年   340篇
  2016年   345篇
  2015年   420篇
  2014年   581篇
  2013年   957篇
  2012年   1321篇
  2011年   1281篇
  2010年   710篇
  2009年   697篇
  2008年   1198篇
  2007年   1165篇
  2006年   1146篇
  2005年   1058篇
  2004年   1097篇
  2003年   1046篇
  2002年   897篇
  2001年   886篇
  2000年   922篇
  1999年   739篇
  1998年   347篇
  1997年   312篇
  1996年   333篇
  1995年   306篇
  1994年   258篇
  1993年   293篇
  1992年   642篇
  1991年   630篇
  1990年   595篇
  1989年   612篇
  1988年   585篇
  1987年   601篇
  1986年   534篇
  1985年   529篇
  1984年   396篇
  1983年   346篇
  1982年   238篇
  1981年   216篇
  1980年   204篇
  1979年   367篇
  1978年   208篇
  1977年   208篇
  1976年   227篇
  1975年   190篇
  1974年   241篇
  1973年   228篇
  1972年   187篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
On the Bubble     
Thompson  Don 《JAMA》2006,296(14):1698
  相似文献   
4.
Choristomas, masses of normal tissues in aberrant locations, contain smooth muscle fibers and fibrous tissues. We describe the MR imaging features of two choristomas located in the internal auditory canals and arising from the facial and vestibulocochlear nerves. Both lesions enhanced with contrast material. In one case, enhancement was seen in the geniculate ganglion and greater superficial petrosal nerve. In the other, a medial component enhanced less than the lateral component did.  相似文献   
5.
As an adjunct to a European multicentre prospective study, five quality assessment (QA) exercises, spanning a period of 2.5 years, were undertaken. In these, fifteen laboratories from eight countries each performed ten haemostatic factor assays. The design of the QA exercises allowed the between-duplicate, between-day and between-laboratory coefficients of variation (CVs) to be calculated. The between-duplicate CV decreased by a factor of one quarter, and the between-day CV by a factor of one third, over the five exercises. The activated partial thromboplastin time (APTT) assay consistently showed the lowest CVs, while there was notable improvement in the between-day CVs for von Willebrand factor related antigen (vWF R:Ag) and factor VIII clotting activity (VIII:C). However, the between-laboratory CV, assessing extent of agreement between the different laboratories, did not apparently improve over the five exercises. Thus, while QA exercises may be very useful in improving the performance of haemostatic assays according to criteria which an individual laboratory can assess, improving agreement on haemostatic assay results between laboratories may be more difficult to achieve.  相似文献   
6.
7.
In the present study we examined the relationship between the induction of long-term potentiation (LTP) in the dentate gyrus of anesthetized rats and activation of immediate early genes (IEGs; c-fos and zif/268) using several different high-frequency stimulation paradigms. Stimulation parameters that effectively induced LTP were not associated with IEG activation. Conversely, stimulation parameters that failed to induce LTP consistently resulted in IEG activation. These results suggest that there is a negative correlation between IEG activation and LTP, and that activation of IEGs is neither necessary nor sufficient for the induction of LTP.  相似文献   
8.
Behavioral state-specific changes in human hippocampal theta activity   总被引:1,自引:0,他引:1  
Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms.  相似文献   
9.
BACKGROUND: Cardiac rehabilitation (CR) has an evidence base but traditional models may not readily apply to people living in rural and remote regions. AIM:: To outline published comprehensive and non-hospital based CR models used for people discharged from hospital after a cardiac event that have potential relevance to those living in rural and remote areas in Australia. METHODS: The PubMed database was searched using Medical subject headings (MeSH) terms and the key word 'cardiac rehabilitation' limited to clinical trials. Articles were retrieved if they included at least two components of CR and were not based in an outpatient setting. RESULTS: No CR models specifically developed for rural and remote areas were identified. However, 14 studies were found that outlined 11 non-conventional comprehensive CR models. All provided CR in a home-based setting. Health professionals provided support via telephone contact or home visits, and via resources such as the Heart Manual. Reported outcomes from these CR programs varied: ranging from an increase in knowledge of risk factors, to improvements in physical activity, decreased risk factor profile, improved psychological and social functioning and reductions in health service costs and mortality. CONCLUSION: Home-based, CR models have the most substantive evidence base and, therefore the greatest potential to be developed and made accessible to eligible people living in rural and remote areas.  相似文献   
10.
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