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   19958篇
  免费   1494篇
  国内免费   72篇
耳鼻咽喉   362篇
儿科学   456篇
妇产科学   348篇
基础医学   3283篇
口腔科学   560篇
临床医学   1824篇
内科学   4166篇
皮肤病学   382篇
神经病学   1688篇
特种医学   980篇
外国民族医学   3篇
外科学   2817篇
综合类   182篇
一般理论   6篇
预防医学   1347篇
眼科学   152篇
药学   1698篇
中国医学   19篇
肿瘤学   1251篇
  2023年   72篇
  2022年   169篇
  2021年   330篇
  2020年   199篇
  2019年   294篇
  2018年   359篇
  2017年   322篇
  2016年   372篇
  2015年   485篇
  2014年   560篇
  2013年   772篇
  2012年   1184篇
  2011年   1258篇
  2010年   697篇
  2009年   669篇
  2008年   1150篇
  2007年   1202篇
  2006年   1130篇
  2005年   1114篇
  2004年   1071篇
  2003年   1050篇
  2002年   952篇
  2001年   401篇
  2000年   421篇
  1999年   416篇
  1998年   246篇
  1997年   261篇
  1996年   185篇
  1995年   202篇
  1994年   173篇
  1993年   165篇
  1992年   299篇
  1991年   283篇
  1990年   271篇
  1989年   268篇
  1988年   202篇
  1987年   229篇
  1986年   205篇
  1985年   167篇
  1984年   177篇
  1983年   156篇
  1982年   138篇
  1981年   109篇
  1980年   104篇
  1979年   134篇
  1978年   113篇
  1977年   88篇
  1975年   75篇
  1974年   86篇
  1972年   71篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Abstract The aim of the present clinical trial was to test tolerability during 2 treatments with EMDOGAIN® in a large number of patients. An open, controlled study design in 10 Swedish specialist clinics was chosen, with a test group of 107 patients treated with EMDOGAIN® in connection with periodontal surgery at 2 surgical test sites per patient. The procedures were performed 2 to 6 weeks apart on one-rooted teeth with at least 4 mm deep intraosseous lesions. A control group of 33 patients underwent flap surgery without EMDOGAIN® at I comparable site. In total 214 test and 33 control surgeries were performed. Serum samples were obtained from test patients for analysis of total and specific antibody levels. 10 of the patients had samples taken before and after the first surgery. 56 other samples were taken after one treatment with EMDOGAIN®, and 63 after 2 treatments. None of the samples, not even from allergy-prone patients after 2 treatments, indicated deviations from established baseline ranges. This indicates that the immunogenic potential of EMDOGAIN® is extremely low when applied in conjunction with periodontal surgery. Comparison between the test and control groups demonstrated the same type and frequency of post-surgical experiences, i.e., reactions caused by the surgical procedure itself. Clinical probing and radiographic evaluation was performed at baseline and 8 months postsurgery. About half of the patients (44 test and 21 control) were also evaluated after 3 years. There was a significant difference between the test and control results at 8 months post surgery. and this difference had increased further at the 3 year follow-up. The 2.5–3 mm increase in attachment and bone level after treatment with EMDOGAIN® was of the same magnitude as seen in the studies with split-mouth design aiming for lest of effectiveness of EMDOGAIN®.  相似文献   
5.
6.
Different psychotropic drugs were investigated in order to determine their effect on the release of prolactin and corticosterone and their influence on the tuberoinfundibular dopamine (TIDA) neuron activity. The results were used in a principal component analysis, which grouped the psychotropic drugs into different clusters. In the plot showing these clusters the anxiolytic drugs were found to be grouped together and differ from the antidepressant drugs by their potent ability to increase plasma corticosterone. The antipsychotic drugs formed a separate group being clustered together. Typical neuroleptic and atypical antipsychotic drugs could be separated within the cluster by their different effects on plasma prolactin and corticosterone and on TIDA neuron activity. The results indicate that the neuroendocrine profiles of antidepressant and anxiolytic drugs are different from those of antipsychotic drugs and that the neuroendocrine measurements could be a useful tool in the early classification of psychotropic drugs. © 1993 Wiley-Liss, Inc.  相似文献   
7.
The influence of left ventricular volume variations and regurgitant fraction variations upon left ventricular ejection fraction, during exercise was examined using equilibrium radionuclide angiography in patients suffering from aortic regurgitation. Ejection fraction (EF), regurgitant fraction (RF), end diastolic volume (EDV) and end systolic volume (ESV) variations from rest to peak exercise were determined in 44 patients suffering from chronic aortic regurgitation (AR) and in 8 healthy volunteers (C). In C, EF increased (+0.10±0.03, P<0.01) and ESV decreased significantly (-23%±12%, P<0.01) RF and EDV did not vary significantly. In AR patients, EF, EDV and ESV did not vary significantly because of important scattering of individual values. Changes in EF and ESV were inversely correlated (r=-0.79, P<0.01) and RF decreased significantly (-0.12±0.10, P<0.01). Volumes and EF changes during exercise occurred in three different ways. In a 1st subgroup of 7 patients, EF increased (+0.09±0.03, P<0.05) in conjunction with a reduction of ESV (-24%±12%, P<0.05) without a significant change in EDV. In a 2nd group of 22 patients. EF decreased (-0.04±0.07, P<0.01) in association with an increase in ESV (+17%±16%, P<0.01) and no change in EDV. In a 3rd subgroup of 15 patients, EF decreased (-0.02±0.06, P<0.01) despite a reduction in ESV (-7%±6%, P<0.01) because of a dramatic EDV decrease (-10%±6%, P<0.05). In this subgroup, changes in EF were inversely correlated with changes in ESV (r=-0.55, P<0.01) and positively related to EDV variations (r=0.42, P=0.02). EDV related to EDV variations (r=0.42, P=0.02). EDV changes were weakly, but significantly, correlated to RF decrease (r=0.39, P<0.05). We conclude that changes in left ventricular ejection fraction during exercise in patients with chronic aortic regurgitation are significantly related in some patients to changes in ventricular loading conditions as well as contractile state. Therefore, a correct interpretation of EF changes during exercise requires the simultaneous determination of changes in LV volumes.Abbreviations EDV end diastolic volume - EF ejection fraction - ESV end systolic volume - LV left ventricle - RV right ventricle  相似文献   
8.
Compromise of immune function in obstructive jaundice.   总被引:5,自引:0,他引:5  
  相似文献   
9.
10.
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