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   1487211篇
  免费   129043篇
  国内免费   6391篇
耳鼻咽喉   21487篇
儿科学   48837篇
妇产科学   38951篇
基础医学   202665篇
口腔科学   37633篇
临床医学   155670篇
内科学   303353篇
皮肤病学   33618篇
神经病学   126583篇
特种医学   54527篇
外国民族医学   372篇
外科学   223183篇
综合类   29455篇
现状与发展   73篇
一般理论   502篇
预防医学   122407篇
眼科学   32304篇
药学   100858篇
  6篇
中国医学   3197篇
肿瘤学   86964篇
  2021年   13773篇
  2020年   12260篇
  2019年   13756篇
  2018年   23156篇
  2017年   19017篇
  2016年   20811篇
  2015年   22804篇
  2014年   35044篇
  2013年   46622篇
  2012年   49897篇
  2011年   52705篇
  2010年   36977篇
  2009年   38208篇
  2008年   48716篇
  2007年   49604篇
  2006年   51956篇
  2005年   47830篇
  2004年   45091篇
  2003年   42053篇
  2002年   40896篇
  2001年   64679篇
  2000年   65661篇
  1999年   55610篇
  1998年   18054篇
  1997年   16490篇
  1996年   16231篇
  1995年   15448篇
  1994年   13483篇
  1993年   12432篇
  1992年   43076篇
  1991年   42344篇
  1990年   40634篇
  1989年   38688篇
  1988年   35744篇
  1987年   34716篇
  1986年   33175篇
  1985年   31503篇
  1984年   23746篇
  1983年   20219篇
  1982年   12349篇
  1979年   21261篇
  1978年   15256篇
  1977年   12525篇
  1976年   12177篇
  1975年   12477篇
  1974年   15134篇
  1973年   14835篇
  1972年   13782篇
  1971年   12737篇
  1970年   11830篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
972.
973.
974.
975.
976.
The health care supervisor responsible for establishing a therapeutic milieu within a traditional hospital organization will have greater success if these suggested management strategies are employed. Decentralizing, improving organizational communication, and clarifying interdisciplinary role relationships are the strategies that support the integration of differing organizational approaches to management.  相似文献   
977.
Cardiac involvement in Lyme disease: manifestations and management   总被引:3,自引:0,他引:3  
Cardiac involvement in Lyme disease may manifest as atrioventricular block, myopericarditis, and left ventricular dysfunction. Diagnosis depends on recognition of the systemic nature of Lyme disease, including cardiac involvement, and its natural history. Serologic tests that are both sensitive and specific may aid in diagnosis. Although current recommendations for the treatment of Lyme disease with carditis include antibiotics and salicylates or corticosteroids, these types of therapy have not been unequivocally demonstrated to alter the natural history of cardiac involvement. Supportive therapy may necessitate temporary transvenous cardiac pacing in symptomatic patients.  相似文献   
978.
979.
Systemic (s.c.) administration of aminooxyacetic acid (AOAA) in mice triggered clonic convulsions with a CD50 (convulsive dose) of 68 mg/kg (range 54-86). AOAA also induced clonic convulsions in mice subjected to intracerebroventricular administration of the drug with a CD50 of 0.04 mumols (range 0.028-0.06). At the onset of convulsions induced by systemic AOAA (CD97;150 mg/kg), the GAD activity in the frontal cortex and hippocampus was not affected. GABA mimetic drugs, progabide and gabaculine, had no effect on convulsions induced by AOAA. Convulsions induced by systemic administration of AOAA were blocked by diazepam, phenobarbital, and valproate. Ethosuximide, trimethadione, acetazolamide, diphenylhydantoin, and carbamazepine remained ineffective. L-Phenylisopropyladenosine was also found to protect mice against AOAA-induced convulsions, whereas atropine and baclofen had no effect. The seizures induced by intracerebroventricular administration of AOAA (CD97; 0.1 mumols) were blocked by coadministration of preferential N-methyl-D-aspartate antagonists, D-(-)-2-aminophosphonoheptanoic (AP7), 3-[+/-)-2-carboxypiperazine-4-yl)-propyl-1-phosphonic (CPP), and kynurenic acid (KYNA); preferential quisqualate/kainate antagonists, 6-cyano-7-nitro-quinoxaline-2,3-dione and gamma-D-glutamylaminomethylsulphonic acid, remained inactive in the range of dosages sufficient to block seizures induced by quisqualic acid or kainic acid. The antagonistic action of antiepileptic drugs effective against seizures induced by excitatory amino acids (diazepam and valproate), and drugs acting on excitatory amino acid receptors (AP7, CPP, and KYNA) upon seizures induced by AOAA suggests an involvement of excitatory neurotransmission in the convulsant action of the drug.  相似文献   
980.
A new technetium-chelating agent based on a triamide monomercaptide tetradentate set of donor groups, mercaptoacetylglycylglycylglycine (MAG3), was synthesized and evaluated. Chelation with 99mTc resulted in a single radiochemical product as expected. Studies in mice of [99mTc]MAG3 indicated excretion rates faster than omicron-iodohippurate (OIH) both in normal and in probenecid treated animals. Specificity for renal excretion was essentially complete. Clearance studies in rats resulted in 2.84 ml/min/100 g for [99mTc]MAG3, 2.17 for OIH, and 1.29 for [125I]iothalamate. Extraction efficiencies were 85% for [99mTc]MAG3, 69% for OIH and 39% for [125I]iothalamate. Probenicid depressed the clearance both of [99mTc]MAG3 and OIH at 25 and 50 mg/kg/hr, but to a greater extent with [99mTc]MAG3. The greater effect is offset, however, by the larger fraction secreted by the renal tubular cells. The animal results suggest that [99mTc]MAG3 may be a useful alternative to [131I]OIH.  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