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   42996篇
  免费   2327篇
  国内免费   157篇
耳鼻咽喉   582篇
儿科学   2744篇
妇产科学   714篇
基础医学   4977篇
口腔科学   1149篇
临床医学   3165篇
内科学   8155篇
皮肤病学   1158篇
神经病学   2596篇
特种医学   1297篇
外科学   6502篇
综合类   1344篇
一般理论   18篇
预防医学   2110篇
眼科学   1599篇
药学   4189篇
  1篇
中国医学   357篇
肿瘤学   2823篇
  2023年   364篇
  2022年   1008篇
  2021年   1771篇
  2020年   941篇
  2019年   1084篇
  2018年   1545篇
  2017年   1101篇
  2016年   1430篇
  2015年   1433篇
  2014年   2110篇
  2013年   2440篇
  2012年   3445篇
  2011年   3354篇
  2010年   1989篇
  2009年   1556篇
  2008年   2242篇
  2007年   2302篇
  2006年   2104篇
  2005年   1842篇
  2004年   1698篇
  2003年   1432篇
  2002年   1221篇
  2001年   786篇
  2000年   723篇
  1999年   599篇
  1998年   280篇
  1997年   223篇
  1996年   228篇
  1995年   198篇
  1994年   156篇
  1993年   133篇
  1992年   352篇
  1991年   338篇
  1990年   360篇
  1989年   330篇
  1988年   287篇
  1987年   241篇
  1986年   234篇
  1985年   229篇
  1984年   175篇
  1983年   122篇
  1982年   68篇
  1981年   76篇
  1980年   69篇
  1979年   109篇
  1978年   71篇
  1977年   87篇
  1976年   65篇
  1973年   62篇
  1971年   60篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
We report a seven-year-old girl who presented with a sudden tumor apoplexy due to a parasagittal hemangiopericytoma. Following tumor excision, the child was noted to have bilateral optic nerve dysfunction and progressive papilledema, despite rapid overall neurological improvement. Based on the clinical features, we feel that this case represents an unusual form of visual deterioration related to impaired CSF absorption somehow precipitated by the acute tumour apoplexy. This unusual case of blindness responded significantly to CSF shunting. Several reports exist describing raised intracranial pressure with papilledema caused by nonthrombotic sinus occlusion due to tumors in proximity to the posterior superior sagittal sinus, torcular herophili and the jugular outlet. Communicating hydrocephalus, pseudotumor syndrome or intracranial venous sinus obstruction should be considered when otherwise inexplicable visual loss coexists with optic nerve dysfunction and papilledema. We emphasize the importance of a thorough search for the cause of visual loss.  相似文献   
82.
We investigated the mechanism(s) responsible for differences in the effects of acidic pH on Ca2+ activation of the activity of adult and neonatal rat heart myofilaments. Studies on preparations of myofilaments reconstituted with adult troponin-tropomyosin (Tn-Tm) and either adult or neonatal thick filaments indicated that the difference in effect of acidic pH is related to differences in Tn-Tm and not other myofilament proteins. Immunoblotting analysis showed that development of the rat heart myofibrils is associated with isoform switching from slow skeletal TnI to cardiac TnI and from a slow mobility isoform of TnT (TnT1) to a faster Mr isoform (TnT2. Expression of slow skeletal TnI was associated with a relative insensitivity of myofilament Ca2+ activation to deactivation by acidic pH. Moreover, the effect of acidic pH on Ca2+ activation of ATPase activity of soleus myofibrils, which contain cardiac TnC and slow skeletal TnI, was essentially the same as the effect of acidic pH on rat cardiac myofibrils in the early neonatal period. Neonatal myofilaments also contained a relative abundance of a set of polypeptides copurifying with the thin filaments. We have identified these proteins as histones. The relative amount of histones among a variety of preparations from different species was not correlated with the pH sensitivity of myofibrillar Ca2+ activation. Shifts in TnT isoforms among these species were also not correlated with an altered response to acidic pH. Our data provide evidence in support of the hypothesis that the relative insensitivity of neonatal myofilament activity to acidic pH is due to the presence of slow skeletal TnI in the thin-filament regulatory complex.  相似文献   
83.
An estimated 38.6 million persons globally are living with HIV, of whom over 1.1 million reside in Zambia. Of the 2 million cases in the US, 64% of new cases among women are among African Americans. Alcohol and drug use represents a significant risk factor for HIV transmission among both Zambians and African Americans. In addition, gender dynamics in both the US and Zambia promote transmission. This study examines two interventions targeting HIV risk behavior among HIV positive substance users, women in Miami, USA (the New Opportunities for Women (NOW) Project) and men in Lusaka, Zambia (the Partner Project). The study compares the efficacy of these two culturally tailored sexual behavior interventions provided in group and individual session formats. US and Zambian participants increased sexual barrier use and reduced substance-related sexual risk. Comparatively greater gains were made by higher risk Zambian males than US females in both group and individual conditions. Among lower risk participants, women in the group condition achieved and sustained the greatest comparative risk reductions. Results suggest that cost effective group HIV transmission risk reduction interventions for multiethnic individuals can be successfully implemented among both female and male drug and alcohol users in multinational settings.  相似文献   
84.
85.
86.
87.
88.
89.
90.
Objective: To determine if drip infusion should be discontinued after full recovery of the patient from anaesthesia after minilaparotomy cholecystectomy in uncomplicated cases.Design: A randomised controlled clinical trial on 60 patients, from the waiting list, of cholelithiasis/cholecystitis operated by minilaparotomy cholecystectomy between November 1995 to March 1996. 30 patients did not receive postoperative IV drip infusion and in 30 patients 12–24 hours of standard drip transfusion was continued according to the current practice.Setting: Single Surgical Unit, SS Hospital, Banaras Hindu University, Varanasi, India.Main outcome measure: Recognition of clinical indication for continuation of. IV drip infusion after full recovery from anaesthesia.Results: In the cohorts of 30 patients each who were or were not given IV drip infusion after full recovery from anaesthesia following minilaparotomy cholecystectomy the observations on pulse rate, blood pressure, time to first voiding of urine and time to start first oral intake of fluids were identical. However postoperative urinary retention occured in 6 (20%) patients in whom the IV drip infusion was given.Conclusion: There is no clinical indication to continue IV drip infusion after full recovery from anaesthesia in patients operated for minilaparotomy cholecystectomy.  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