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   1640篇
  免费   96篇
  国内免费   21篇
耳鼻咽喉   7篇
儿科学   54篇
妇产科学   10篇
基础医学   181篇
口腔科学   45篇
临床医学   181篇
内科学   461篇
皮肤病学   26篇
神经病学   116篇
特种医学   153篇
外国民族医学   1篇
外科学   188篇
综合类   25篇
预防医学   91篇
眼科学   33篇
药学   108篇
肿瘤学   77篇
  2022年   5篇
  2021年   31篇
  2020年   17篇
  2019年   15篇
  2018年   30篇
  2017年   30篇
  2016年   31篇
  2015年   33篇
  2014年   41篇
  2013年   57篇
  2012年   52篇
  2011年   72篇
  2010年   57篇
  2009年   62篇
  2008年   59篇
  2007年   70篇
  2006年   89篇
  2005年   78篇
  2004年   70篇
  2003年   53篇
  2002年   51篇
  2001年   65篇
  2000年   52篇
  1999年   42篇
  1998年   50篇
  1997年   45篇
  1996年   35篇
  1995年   35篇
  1994年   12篇
  1993年   21篇
  1992年   23篇
  1991年   17篇
  1990年   28篇
  1989年   42篇
  1988年   39篇
  1987年   34篇
  1986年   19篇
  1985年   23篇
  1984年   13篇
  1983年   13篇
  1982年   15篇
  1981年   15篇
  1980年   16篇
  1979年   10篇
  1978年   7篇
  1977年   9篇
  1976年   9篇
  1975年   8篇
  1973年   5篇
  1969年   6篇
排序方式: 共有1757条查询结果,搜索用时 31 毫秒
1.
OBJECTIVE: Neighborhood sociodemographic characteristics may be important to the mental health of older adults who have decreased mobility and fewer resources. Our objective was to examine the association between neighborhood context and level of depressive symptomatology in older adults in a diverse geographic region of central North Carolina. METHODS: The sample included 2,998 adults 65 or older residing in 91 census tracts. Depressive symptoms were measured using the Center for Epidemiologic Studies-Depression scale (CES-D). Neighborhoods were characterized by five census-based characteristics: socioeconomic disadvantage, socioeconomic advantage, racial/ethnic heterogeneity, residential stability, and age structure. RESULTS: In ecologic level analyses, level of census tract socioeconomic disadvantage was associated with increased depressive symptoms. To determine whether neighborhood context was associated with depressive symptoms independently of individual characteristics, the authors used multilevel modeling. The authors examined the ability of each of five neighborhood (level 2) characteristics to predict a level 1 outcome (CES-D symptoms) controlling for the effects of individual (level 1) characteristics. Younger age, being widowed, lower income, and having some functional limitations were associated with increased depression symptoms conditional on census tract random effects. However, none of the neighborhood characteristics was significantly associated with depression symptoms, conditional on census tract random effects, either unadjusted or adjusted for individual characteristics. CONCLUSION: Any observed association between neighborhood sociodemographic characteristics and individual depressive symptoms in our sample may reflect the characteristics of the individuals who reside in the neighborhood rather than the neighborhood characteristics themselves. The use of multilevel modeling is important to separate these effects.  相似文献   
2.
Occupational diseases Nos. 2108 and 2110 correspond to intervertebral disc-related diseases of the lumbar spine from many years of carrying or lifting heavy loads, occupations in extreme postures of full flexion or oscillation of the whole body when seated, and which compel the cessation of all activities which are or could be the cause for the origin, exacerbation or recurrence of the disease. These occupational diseases came into force at the start of 1993, but there have been considerable problems in their implementation. The present Part I of the contribution is the result of the work of an interdisciplinary study group and contains medical criteria for the assessment of possibly strain-related clinical characteristics and the evaluation of other possible causes. Part II is to be published in Volume 4/2005 and will deal with questions related to forced cessation and to the assessment of the loss of earning ability. Agreement was reached in many areas related to the assessment of occupational claims. This should allow for evidence-based decision making in the future for the occupational diseases Nos. 2108 and 2110.  相似文献   
3.
4.
The first part of this serial paper dealt with the medical criteria used in evaluation of the clinical picture caused by physical stress and the evaluation of other candidate causes and was published in issue no. 3/2005 (pp. 711–752) of Trauma and Berufskrankheit. This follow-up paper (II) presents criteria to be used in the evaluation of whether it is necessary to give up the occupations putting the spine at risk and in estimation of the degree of disability.  相似文献   
5.
6.
麦冬类中药组织切片计算机三维重建图鉴   总被引:9,自引:0,他引:9  
利用计算机技术实现麦冬类中药组织连续切片三维重建与动态显示,为计算机辅助生药学鉴定和教学提供了新的三维图像技术和研究资料。  相似文献   
7.
用混合粘合剂碳糊电极测定丁螺环酮   总被引:6,自引:1,他引:5  
用混合粘合剂碳糊电极测定丁螺环酮张正奇,曾鸽鸣,刘传桂,黎艳飞(湖南大学化学化工系,长沙410082)碳糊电极无毒,制作方便,表面更新容易,应用电位范围广,在药物分析中已有应用[1~5]。我们在液体石腊中加入添加剂,组成混合粘合剂,可显著改善电极的检...  相似文献   
8.
Starting from 4,4'-diamino-diphenylsulfone (DDS) as a lead structure, new 2-substituted analogues as well as new 2-substituted 4-alkylamino-4'-amino diphenylsulfones have been designed and synthetized in different ways. This has led to compounds the inhibitory activity of which against 7,8-dihydropteroic acid synthase of plasmodia and mycobacteria is clearly superior to that of sulfadoxine and in most cases to that of DDS. Of special interest is 4'-amino-4-n-propylamino-2-methyl-diphenylsulfone. Together with inhibitors of 7,8-dihydrofolate reductase in vitro and in vivo it possesses a marked synergistic inhibitory activity against plasmodia. In contrast to DDS in doses up to 200 mg/kg p.o. (cat) no methemoglobin formation is observed. The compound has been selected for further studies.  相似文献   
9.
10.
In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications.  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