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   12633篇
  免费   1160篇
  国内免费   22篇
耳鼻咽喉   95篇
儿科学   461篇
妇产科学   327篇
基础医学   1593篇
口腔科学   357篇
临床医学   1405篇
内科学   2262篇
皮肤病学   415篇
神经病学   1013篇
特种医学   485篇
外科学   1864篇
综合类   534篇
一般理论   12篇
预防医学   1334篇
眼科学   196篇
药学   871篇
中国医学   10篇
肿瘤学   581篇
  2021年   203篇
  2020年   106篇
  2019年   162篇
  2018年   210篇
  2017年   147篇
  2016年   159篇
  2015年   153篇
  2014年   250篇
  2013年   359篇
  2012年   547篇
  2011年   532篇
  2010年   339篇
  2009年   305篇
  2008年   526篇
  2007年   579篇
  2006年   570篇
  2005年   474篇
  2004年   505篇
  2003年   481篇
  2002年   488篇
  2001年   386篇
  2000年   464篇
  1999年   393篇
  1998年   179篇
  1997年   182篇
  1996年   152篇
  1995年   132篇
  1994年   127篇
  1993年   133篇
  1992年   290篇
  1991年   290篇
  1990年   282篇
  1989年   328篇
  1988年   251篇
  1987年   262篇
  1986年   231篇
  1985年   267篇
  1984年   174篇
  1983年   135篇
  1982年   119篇
  1981年   126篇
  1980年   96篇
  1979年   165篇
  1978年   129篇
  1977年   118篇
  1976年   93篇
  1975年   96篇
  1974年   94篇
  1973年   112篇
  1972年   98篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
3.
4.
BACKGROUND: The validity of parent reports regarding children's attention-deficit/hyperactivity disorder (ADHD) symptoms has been questioned. This study assessed whether parent reports were as sensitive as teacher reports to document change in ADHD symptoms during clinical trials with atomoxetine. METHODS: Data were compared from two randomized, double-blind, placebo-controlled clinical trials of atomoxetine using different versions (parent or teacher) of the same rating scale (Attention-Deficit/Hyperactivity Disorder Rating Scale-IV [parent or teacher] Version: Investigator Administered and Scored - ADHD RS). Exclusion criteria included history of bipolar disorder, psychosis, seizures, alcohol abuse, or positive drug screen. Patients (6-16 years old) were treated with atomoxetine (titrated to a maximum dose of 1.8 mg/kg/day) administered once daily for up to 7 weeks. Parent and teacher ratings were compared using an analysis of covariance (ANCOVA) model. RESULTS: The analysis (n = 318) showed that treatment effects (mean change, baseline to endpoint) were similar between parent and teacher ratings (total, p = .762; inattention, p = .519; hyperactive/impulsive, p = .955). Effect sizes also were similar based on total scores (parent ratings = .69; teacher ratings = .63). CONCLUSIONS: Parent reports are as sensitive as teacher reports in assessing the efficacy of long-acting pharmacologic treatment for ADHD in children during clinical trials using the nonstimulant atomoxetine.  相似文献   
5.
6.
7.
8.
Background.Computers that collect data from patients and provide both patients and practitioners with printed feedback on a range of health risks are a tool for assisting general practitioners with preventive care. This study assessed the impact of computer-generated printed feedback on cervical screening among women who were underscreened for cervical cancer.Method.Female attenders at two Australian general practices were randomly allocated to Experimental or Control groups. Women in both groups completed a health risk survey on a touch screen computer prior to their consultation. Those in the Experimental group received printed pages summarizing their results, including their eligibility for cervical screening and last Pap test, for themselves and their doctor. The number and proportion of underscreened women who had a Pap test in the 6 months after completing the computer survey, as determined by pathology records, were examined.Results.Of the 679 participants, 139 were classified as underscreened on the basis of self-report (74 Experimental, 65 Control) and 272 on the basis of their pathology records (148 Experimental, 124 Control). Overall about one-third of women had a test in the 6-month period, and the differences between the groups were not significant for women overall (18–70 years) or for women 18–49 years. Among women 50–70 who were underscreened based on self-report, those receiving the printout were more likely to have a Pap test in the next 6 months (P< 0.05). This pattern was also evident, but did not reach statistical significance, for older women who were underscreened based on pathology records.Conclusions.We are unable to draw conclusions regarding the effectiveness of the computer system due to the modest proportions of women screened, the small numbers, and the fact that the computer survey may have created an intervention effect in the Control group. As the study suggests the computer system is acceptable to women and may be effective for encouraging screening among older women, further exploration of the system is desirable.  相似文献   
9.
10.
The adult mammalian central nervous system (CNS) lacks the capacity to support axonal regeneration. There is increasing evidence to suggest that astrocytes, the major glial population in the CNS, may possess both axon-growth promoting and axon-growth inhibitory properties and the latter may contribute to the poor regenerative capacity of the CNS. In order to examine the molecular differences between axon-growth permissive and axon-growth inhibitory astrocytes, a panel of astrocyte cell lines exhibiting a range of axon-growth promoting properties was generated and analysed. No clear correlation was found between the axon-growth promoting properties of these astrocyte cell lines with: (i) the expression of known neurite-outgrowth promoting molecules such as laminin, fibronectin andN-cadherin; (ii) the expression of known inhibitory molecules such tenascin and chondroitin sulphate proteoglycan; (iii) plasminogen activator and plasminogen activator inhibitor activity; and (iv) growth cone collapsing activity. EM studies on aggregates formed from astrocyte cell lines, however, revealed the presence of an abundance of extracellular matrix material associated with the more inhibitory astrocyte cell lines. When matrix deposited by astrocyte cell lines was assessed for axon-growth promoting activity, matrix from permissive lines was found to be a good substrate, whereas matrix from the inhibitory astrocyte lines was a poor substrate for neuritic growth. Our findings, taken together, suggest that the functional differences between the permissive and the inhibitory astrocyte cell lines reside largely with the ECM.  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