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   1902483篇
  免费   161534篇
  国内免费   24953篇
耳鼻咽喉   24498篇
儿科学   56151篇
妇产科学   50949篇
基础医学   265022篇
口腔科学   52469篇
临床医学   183894篇
内科学   358780篇
皮肤病学   36986篇
神经病学   147171篇
特种医学   76172篇
外国民族医学   687篇
外科学   274550篇
综合类   88723篇
现状与发展   79篇
一般理论   563篇
预防医学   140882篇
眼科学   45606篇
药学   152426篇
  330篇
中国医学   20283篇
肿瘤学   112749篇
  2021年   26043篇
  2020年   18080篇
  2019年   21068篇
  2018年   25841篇
  2017年   21321篇
  2016年   21981篇
  2015年   29014篇
  2014年   37968篇
  2013年   46182篇
  2012年   64506篇
  2011年   69717篇
  2010年   41755篇
  2009年   37136篇
  2008年   59327篇
  2007年   61575篇
  2006年   62447篇
  2005年   60870篇
  2004年   54233篇
  2003年   51569篇
  2002年   49342篇
  2001年   82200篇
  2000年   85703篇
  1999年   74642篇
  1998年   22961篇
  1997年   21643篇
  1996年   20496篇
  1995年   19839篇
  1994年   18181篇
  1993年   16218篇
  1992年   57926篇
  1991年   55898篇
  1990年   54450篇
  1989年   52505篇
  1988年   48610篇
  1987年   47693篇
  1986年   45229篇
  1985年   43624篇
  1984年   32475篇
  1983年   27876篇
  1982年   16344篇
  1979年   30619篇
  1978年   21070篇
  1977年   17758篇
  1976年   16698篇
  1975年   17565篇
  1974年   21528篇
  1973年   20704篇
  1972年   18898篇
  1971年   17791篇
  1970年   16311篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
81.
82.
83.
Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.  相似文献   
84.
85.
86.
87.
Since the new round of health care reform in 2009, the vertical integration of hospitals and primary health institutions has become widely implemented in China as an efficient method for improving quality of primary care. This study aimed to answer the following questions: (a) What is the perceived quality of township health centres (THCs) under integration? (B) What differences could be observed among the three typical integration models, namely, private hospital-THC integration, public hospital-THC integration, and loose collaboration? Two rounds of cross-sectional surveys were conducted from November 2016 to June 2018. The Chinese version of the Primary Care Assessment Tool was used to evaluate perceived quality of sample THCs, and 1118 adult patients were interviewed in total. Multiple linear regressions were employed to compare the quality scores between two survey rounds and among different integration models after controlling for potential confounders. The results revealed that the quality of care significantly improved under private hospital-THC integration as observed by comparing two survey rounds, while no change or slight changes were observed in the other two models. The difference observed among the three models was that the perceived quality of THCs integrated with private hospitals was worse than that of THCs integrated with public hospitals and THCs under loose collaboration, while no significant difference was observed between public hospital-THC integration and loose collaboration. Increased attention should be given to highlighting the tight integration between hospitals and THCs and the different roles played by private and public hospitals in the current reform.  相似文献   
88.
患者男,64岁,因头颅增大、面部变长,颧骨隆起、下颌增大、双手掌肥厚、双手指粗短30余年,乳房肿物1年余就诊。患者30余年前无明显诱因出现渐进性手足增大,双手掌肥厚,嘴唇变厚,下颌增大,眉弓及颧骨突出,皮肤增厚,无乳腺增大、泌乳,未诊治……  相似文献   
89.

Background

Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.

Methods

Resistin levels were measured in plasma and sputum from three retrospective CF cohorts spanning a wide range of disease. We also assessed the ability of neutrophils to secrete resistin upon activation in vitro. Finally, we constructed a multivariate model assessing the relationship between resistin levels and lung function.

Results

Plasma resistin levels were only marginally higher in CF than in healthy control subjects. By contrast, sputum resistin levels were very high in CF, reaching 50–100 fold higher levels than in plasma. Among CF patients, higher plasma resistin levels were associated with allergic bronchopulmonary aspergillosis, and higher sputum resistin levels were associated with CF-related diabetes. Mechanistically, in vitro release of neutrophil primary granules was concomitant with resistin secretion. Overall, sputum resistin levels were negatively correlated with CF lung function, independently of other variables (age, sex, and genotype).

Conclusions

Our data establish relationships between resistin levels in the plasma and sputum of CF patients that correlate with disease status, and identify resistin as a novel mechanistic link between neutrophilic inflammation and lung disease in CF.  相似文献   
90.
当代社会,老年人口比例呈现不断上升的趋势,老龄化问题日益严峻。因此,如何有效地延缓衰老不仅成为了世界医学研究的热点,也成为了全球亟待解决的问题。中医药在延缓衰老方面经验丰富,而滋阴药在此类研究中效果显著。本文通过整理滋阴药抗衰老作用机制的若干文献,对滋阴复方六味地黄丸、二至丸、左归丸及其他滋阴中药延缓衰老的机制研究进展进行综述。  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