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   2502093篇
  免费   182802篇
  国内免费   3818篇
耳鼻咽喉   33773篇
儿科学   80015篇
妇产科学   65876篇
基础医学   367880篇
口腔科学   67146篇
临床医学   226379篇
内科学   488304篇
皮肤病学   53723篇
神经病学   200262篇
特种医学   92874篇
外国民族医学   502篇
外科学   377239篇
综合类   50239篇
现状与发展   14篇
一般理论   1087篇
预防医学   197755篇
眼科学   57614篇
药学   185740篇
  12篇
中国医学   4806篇
肿瘤学   137473篇
  2021年   21332篇
  2019年   21797篇
  2018年   29819篇
  2017年   22638篇
  2016年   25111篇
  2015年   28503篇
  2014年   40287篇
  2013年   60333篇
  2012年   83684篇
  2011年   89521篇
  2010年   52870篇
  2009年   49791篇
  2008年   84411篇
  2007年   89812篇
  2006年   90301篇
  2005年   88181篇
  2004年   84390篇
  2003年   81081篇
  2002年   78450篇
  2001年   110152篇
  2000年   112527篇
  1999年   95022篇
  1998年   29021篇
  1997年   25464篇
  1996年   25693篇
  1995年   24164篇
  1994年   22232篇
  1993年   20972篇
  1992年   72919篇
  1991年   70956篇
  1990年   69208篇
  1989年   66363篇
  1988年   61075篇
  1987年   59891篇
  1986年   56000篇
  1985年   53833篇
  1984年   40429篇
  1983年   34534篇
  1982年   21209篇
  1979年   36497篇
  1978年   26382篇
  1977年   21939篇
  1976年   20996篇
  1975年   22369篇
  1974年   26703篇
  1973年   25304篇
  1972年   23544篇
  1971年   22313篇
  1970年   20515篇
  1969年   19515篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Migräne     
Migraine is a prevalent disease that affects women more frequently than men. A particular trigger for migraine is the perimenstrual period. Acute migraine attacks during menstruation are treated similarly to nonmenstrual attacks, e.g., with analgesics or triptans. In women with pure menstrual migraine, short-term prophylaxis can be performed with nonsteroidal anti-inflammatory drugs (NSAIDs), estrogens, or low-dose triptans. During pregnancy migraine improves. After menopause frequency and severity of migraine attacks improve.  相似文献   
992.
993.
994.
995.
996.
Operator's determined (D) and stochastic (S) performance depends on the level of readiness and synchronization of the frontoparietal and parietooccipital cortex areas. The developed feedback algorithm was tested in two series of experiments with volunteered subjects doing computer simulation tasks. The experiments showed feasibility to elaborate feedback adaptive control skills that will sustain for a month period.  相似文献   
997.
Head-down tilting of primates (HOT) is a universal method of studying the hypokinetic syndrome effects on functionality of various body systems. Clinical biochemical blood assay was performed in a 25-day HDT experiment (-5 degrees) with 11 Macaca rhesus. One group of animals was kept tilted all the time through, whereas the other was periodically returned into the orthostatic position for 30 to 120 minutes 4-5 times a week. Dry chemistry was employed in biochemical analysis of blood serum and enzyme immunodetection (EID) in measuring blood hormones. As a rule, the biochemical parameters of primates' serum were within the physiological norm range. Shifts in protein, carbohydrate and mineral metabolism were sought for and enzymic activity in blood serum and hormone concentrations were determined. HDT did not produce noteworthy changes in blood concentrations of somatotropic hormone, thyrotrophic hormone (TTH), triiodothyronine (T3), thyroxine (T4) or cortisol. Animals of both groups showed statistically reliable decrease in blood osteocalcine. The preventive complex did not contribute materially to the control of metabolic homeostasis and endocrine function of the primates adapting to the 25-day HDT.  相似文献   
998.
Experiments on Japanese quail embryogenesis on a background of chronic exposure to gamma- and neutron doses comparable with the doses of ionized radiation inside the orbital space stations Mir and ISS, and exploration vehicles gave evidence that permanent absorption of low gamma-doses (0,15 cgy/d) did not impact development of the Japanese quail embryos. On the contrary, the neutron dose of 200 microgy/d imparted by the neutron flux of 30 particles/cm2s was hazardous to embryos as it caused morphological disorders in 12% of embryos.  相似文献   
999.
AIMS: A rare case of the insulin autoimmune syndrome (IAS) accompanied by insulin receptor anomaly is reported. METHODS: Antibodies to insulin and insulin receptor were determined in the patient with severe hypoglycaemia before and after the treatment with prednisolone. RESULTS: Titers of antibody to insulin and insulin receptors were 73.0% and 41.5%, respectively. Drug-induced lymphocyte stimulation tests were all negative for the suspicious drugs. Her HLA-DR was DRB1*0403/04051. Following steroid therapy, the formation of antibodies was suppressed and alleviated her symptoms. Scatchard analysis yielded findings specific to polyclonal antibodies. CONCLUSIONS: The changes in autoantibodies resulted in alleviation of the hypoglycemic symptoms as a result of steroid therapy.  相似文献   
1000.
This study compared the predictive value of the theory of planned behavior in university students in South Africa (N = 251) and the United States (N = 160) who completed an anonymous self-administered questionnaire. Multiple regression analyses revealed that condom use and intention were significantly predicted by positive condom attitude, subjective norm, self-efficacy, and attending university in South Africa. Significant interactions between country and predictors indicated that subjective norm predicted condom use and intention more strongly in the American sample than in the South African sample; attitude predicted intention more strongly in the American sample than in the South African sample; but self-efficacy predicted intention more strongly in the South African sample than in the American sample. The theory of planned behavior may provide a useful framework for interventions to reduce South African students' risk of HIV/and sexuality transmitted diseases. Such interventions should especially focus on building self-efficacy to use condoms.  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