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   6429篇
  免费   306篇
  国内免费   55篇
耳鼻咽喉   35篇
儿科学   145篇
妇产科学   155篇
基础医学   882篇
口腔科学   126篇
临床医学   526篇
内科学   1605篇
皮肤病学   108篇
神经病学   486篇
特种医学   371篇
外科学   900篇
综合类   28篇
预防医学   245篇
眼科学   71篇
药学   488篇
中国医学   19篇
肿瘤学   600篇
  2023年   31篇
  2022年   47篇
  2021年   120篇
  2020年   70篇
  2019年   85篇
  2018年   92篇
  2017年   80篇
  2016年   117篇
  2015年   112篇
  2014年   169篇
  2013年   181篇
  2012年   290篇
  2011年   385篇
  2010年   201篇
  2009年   181篇
  2008年   300篇
  2007年   334篇
  2006年   318篇
  2005年   338篇
  2004年   368篇
  2003年   347篇
  2002年   298篇
  2001年   189篇
  2000年   195篇
  1999年   171篇
  1998年   72篇
  1997年   80篇
  1996年   60篇
  1995年   41篇
  1994年   42篇
  1993年   39篇
  1992年   104篇
  1991年   121篇
  1990年   123篇
  1989年   89篇
  1988年   95篇
  1987年   89篇
  1986年   97篇
  1985年   85篇
  1984年   65篇
  1983年   48篇
  1982年   28篇
  1979年   36篇
  1978年   36篇
  1977年   37篇
  1975年   33篇
  1974年   40篇
  1972年   42篇
  1971年   36篇
  1968年   34篇
排序方式: 共有6790条查询结果,搜索用时 15 毫秒
131.
132.
In eye movement examination, video-oculographic monocular recording has become more popular than electro-oculographic binocular recording. The aim of this study was to examine the characteristics of monocular movements recorded using video-oculography. In 66 healthy subjects, the horizontal saccades and smooth pursuit eye movements of the right eye within a range of 30º were evaluated using a video-oculographic eye movement recording system. Saccade latency, velocity, accuracy, and smooth pursuit gain were measured and analysed by age and direction. Saccade parameters (latency, velocity, and amplitude) and smooth pursuit gain deteriorated with age in healthy subjects. Saccade velocity and accuracy were significantly larger during adduction than during abduction. The smooth pursuit gain did not differ between adduction and abduction. In conclusion, unlike smooth pursuit eye movements, saccadic eye movements have adduction-abduction asymmetry. In video-oculographic monocular recording of saccades, it is necessary to recognise the possibility of the existence of adduction-abduction asymmetry.  相似文献   
133.
134.
Summary Brush border and basal plasma membrane vesicles prepared from normal term human placental syncytiotrophoblast have been used to study amino acid transport. Such studies are reviewed and novel results presented which confirm that saturation of placental transport by phenylalanine is unlikely to limit delivery of this amino acid to the fetus even with grossly raised maternal concentrations. Such raised maternal levels of phenylalanine are, however, likely to severely embarrass the delivery to the fetus across the placental brush border membrane ofl-tyrosine and, to a lesser extent, ofl-tryptophan. Reasons for thinking that this may be relevant to the fetal damage found in maternal PKU are discussed.  相似文献   
135.
136.
137.
The liver has been considered as a tolerogenic organ in the sense that favors the induction of peripheral tolerance. The administration of antigens (Ags) via the portal vein causes tolerance, which is termed portal vein tolerance and can explain the occurrence of tolerogenic responses in the liver. Here we discuss the fundamental mechanisms accounting for portal vein tolerance. Antigen-presenting cells (APCs) in the liver, especially dendritic cells and sinusoidal endothelial cells, have limited the ability to produce pro-inflammatory cytokines upon stimulation with endotoxin, an effect that could be due to the continuous exposure to bacterial Ags derived from intestinal microflora. Ag presentation by liver APCs results in T cell tolerance through clonal deletion and selection of regulatory T cells. Thus, APCs with immunosuppressive functions are associated with the achievement of portal vein tolerance via the induction of clonal deletion and generation of regulatory T cells.  相似文献   
138.
139.
A 56-year-old woman with Ph1--Positive acute Lymphoblastic Leukemia was admitted to our hospital for induction chemotherapy in June 1999. The patient was presented with a central scotoma of left eye during treatment course and was given diagnosis of endophthalmitis. Thereafter she also developed skin induration and suffered from serious pneumonia. Amphotericin B administration was started because of high titer of beta-D-glucan, but soon discontinued due to its adverse effect. Blood cultures yielded colonies of fungus and it was identified Fusarium solani. Her general condition deteriorated with progression of pneumonia, and she died of respiratory insufficiency. Autopsy was performed, and its specimen revealed the disseminated infection of Fusarium solani (lung, eye, heart, kidney and skin). We should pay special attention to the fusariosis in Japan also.  相似文献   
140.
OBJECTIVE: The novel vaso-constricting 31-amino acid-length endothelin-1 [ET-1(1-31)] is selectively produced by human mast cell chymase via its action on big ET-1. However, the pathological role of ET-1(1-31) in atherosclerosis remains unclear. The aim of this study was to clarify vasoconstrictive response and expression of ET-1(1-31) in atherosclerotic aorta. METHODS AND RESULTS: Syrian golden hamster, was used for preparing the atherosclerotic models by the administration of a high cholesterol diet (HC), treatment with the nitric oxide synthase inhibitor (Nomega-nitro-L-arginine methylester, L-NAME) alone, or both (HC and L-NAME) for 40 weeks. Early atherosclerosis was observed in the case of HC or L-NAME alone treatments respectively and severe atherosclerosis was observed in the case of combined HC and L-NAME treatment. Vasoconstriction induced by ET-1(1-31) was not altered by the atherosclerotic changes, but the expression pattern of ET-1(1-31) was different at each stage of the atherosclerotic aorta. ET-1(1-31) was observed rarely in normal aortas or in early atherosclerotic lesions, but ET-1(1-31) expression was dramatically increased in aortic neointima and adventitia in a state of atherosclerosis with severe inflammation. CONCLUSION: ET-1(1-31) might play in a role of promoting atherosclerosis, and especially be involved in inflammatory mediation during the progression of atherosclerosis.  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