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   25474篇
  免费   1944篇
  国内免费   87篇
耳鼻咽喉   291篇
儿科学   665篇
妇产科学   552篇
基础医学   3096篇
口腔科学   573篇
临床医学   2731篇
内科学   4869篇
皮肤病学   256篇
神经病学   2587篇
特种医学   887篇
外国民族医学   3篇
外科学   4017篇
综合类   396篇
一般理论   18篇
预防医学   2289篇
眼科学   564篇
药学   1995篇
中国医学   19篇
肿瘤学   1697篇
  2023年   117篇
  2022年   199篇
  2021年   406篇
  2020年   277篇
  2019年   444篇
  2018年   519篇
  2017年   370篇
  2016年   408篇
  2015年   513篇
  2014年   706篇
  2013年   1079篇
  2012年   1614篇
  2011年   1703篇
  2010年   962篇
  2009年   826篇
  2008年   1606篇
  2007年   1764篇
  2006年   1547篇
  2005年   1538篇
  2004年   1583篇
  2003年   1413篇
  2002年   1380篇
  2001年   360篇
  2000年   320篇
  1999年   360篇
  1998年   333篇
  1997年   284篇
  1996年   237篇
  1995年   202篇
  1994年   191篇
  1993年   204篇
  1992年   310篇
  1991年   276篇
  1990年   234篇
  1989年   237篇
  1988年   206篇
  1987年   203篇
  1986年   178篇
  1985年   168篇
  1984年   139篇
  1983年   143篇
  1982年   132篇
  1981年   137篇
  1980年   111篇
  1979年   111篇
  1978年   114篇
  1976年   110篇
  1975年   119篇
  1974年   106篇
  1972年   122篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
BACKGROUND: Pravastatin and simvastatin prolong survival and reduce transplant-related coronary vasculopathy, although low-density lipoprotein (LDL) lowering with these agents is only modest. The objective of this study was to assess the safety of moderate dose atorvastatin and its efficacy when prior treatment with another statin had failed to lower LDL to < 100 mg/dl. METHODS: Data from 185 patients were retrospectively evaluated for adverse events, duration of exposure (person-days), and the mean atorvastatin dose exposure. Changes in lipid parameters, and prednisone and cyclosporine doses were determined. RESULTS: Safety: 48 patients received atorvastatin for 24,240 person-days at a mean dose exposure of 21 +/- 10 mg. Rhabdomyolysis, myositis, myalgias, and hepatotoxicity occurred in 0, 2, 2, and 0 patients, respectively. All events occurred at the 10-mg dose, within the first 3 months, and were rapidly reversible with atorvastatin discontinuation. Efficacy: Thirty-four patients evaluable for efficacy analyses had a pre-atorvastatin LDL of 145 +/- 38 mg/dl on the following statins: pravastatin (n = 30, 40 +/- 0mg), fluvastatin (n = 3, 33 +/- 12 mg), simvastatin (n = 1, 40 mg). After atorvastatin (21 +/- 9 mg/day) for 133 +/- 67 days, LDL was reduced to 97 +/- 24 mg/dl (relative reduction 31 +/- 20%, p < 0.0001). At the end of the observation period (418 +/- 229 days, atorvastatin final dose 24 +/- 14 mg/day), LDL was further decreased to 88 +/- 23 mg (relative reduction 37 +/- 17%, p < 0.0001). CONCLUSION: Atorvastatin, when used at moderate doses and with close biochemical and clinical monitoring, appears to be safe and is effective in aggressively lowering LDL in heart transplant recipients when treatment with other statins has failed to achieve LDL goals.  相似文献   
56.
The effect of heparin on plasma ionised calcium was studied by adding it in increasing amounts to whole blood from 10 normal subjects. There was no significant change in ionised calcium from the addition of 1 U/ml but a significant fall of 0.02 mmol/1 when 2 U/ml were added and a progressive further fall with increasing concentrations. Heparin from three different manufacturers produced similar results. The effect of heparinisation in vivo was studied during regular haemodialysis on 10 patients with chronic renal failure. Following intravenous injection of 10000 U of heparin there was a consistent and significant fall averaging 0.03 mmol/l.  相似文献   
57.
The authors measure the efficacy of three methods for predicting the time to infection for susceptible individuals in a population undergoing an HIV epidemic. The methods differ in whether they require detailed information of the contact network and whether they require knowledge of the initial source of infection. Efficacy is evaluated using simulations for 20 different contact patterns. Only the risk score that uses both kinds of information accounts for more than 15 per cent of individual variability. The efficacy of this score ranges from 10 per cent in very unstructured populations to 60 per cent for spatially localized contact networks. This improved performance may be explained by the larger fraction of the total variability not due to the disease dynamics. When all variables are dichotomized, the two poorer methods produce odds ratios between 1.4 and 2.3. The odds ratio for the risk score with full information ranges from 2.5 to 17. Risk assessment protocols and intervention programmes are encouraged to assess contact patterns and detect sources of infection.  相似文献   
58.
59.
A case of meningitis secondary to acute suppurative otitis media in a previously healthy child is reported. The only organism isolated from blood after aerobic and prolonged anaerobic culture was identified as Fusobacterium necrophorum. Complete recovery followed treatment with surgery and prolonged antibiotic therapy. The role of anaerobes in the development of meningitis, the isolation and identification of Fusobacterium necrophorum, the clinical presentations of F. necrophorum infection and the choice of antibiotics in the treatment of these infections are discussed.  相似文献   
60.
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