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   2314930篇
  免费   175165篇
  国内免费   7444篇
耳鼻咽喉   31218篇
儿科学   74563篇
妇产科学   62186篇
基础医学   322934篇
口腔科学   65364篇
临床医学   207960篇
内科学   457972篇
皮肤病学   54980篇
神经病学   187122篇
特种医学   94280篇
外国民族医学   472篇
外科学   357457篇
综合类   49821篇
现状与发展   3篇
一般理论   690篇
预防医学   174527篇
眼科学   51104篇
药学   171999篇
  10篇
中国医学   4684篇
肿瘤学   128193篇
  2018年   24630篇
  2017年   19610篇
  2016年   23218篇
  2015年   25232篇
  2014年   34394篇
  2013年   51910篇
  2012年   66357篇
  2011年   71215篇
  2010年   43195篇
  2009年   40614篇
  2008年   66968篇
  2007年   71443篇
  2006年   72562篇
  2005年   69848篇
  2004年   66747篇
  2003年   64989篇
  2002年   62389篇
  2001年   115264篇
  2000年   119408篇
  1999年   98788篇
  1998年   27742篇
  1997年   24628篇
  1996年   25248篇
  1995年   24756篇
  1994年   22897篇
  1993年   21600篇
  1992年   77624篇
  1991年   75209篇
  1990年   73004篇
  1989年   70110篇
  1988年   64202篇
  1987年   62967篇
  1986年   59312篇
  1985年   56862篇
  1984年   42500篇
  1983年   35759篇
  1982年   21471篇
  1981年   19008篇
  1980年   18001篇
  1979年   38144篇
  1978年   26907篇
  1977年   23310篇
  1976年   20917篇
  1975年   22567篇
  1974年   26372篇
  1973年   25312篇
  1972年   23647篇
  1971年   22002篇
  1970年   20162篇
  1969年   19143篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
Purpose: To use polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) calculation to diagnose infectious uveitis.

Methods: Prospective cross-sectional study.

Results: Twenty-seven of 106 patients had positive PCR and/or GWC results on aqueous humor (AH) sampling and 15 of 27 (55.6%) were HIV-positive. Patients with non-anterior uveitis (NAU) were more likely to be HIV+ (p = 0.005). More than 1 possible pathogen was identified in 9 of 27 patients of whom 7 were HIV+. The final clinical diagnosis was discordant with AH findings in 9 of 27 cases. A positive EBV PCR result was associated with a discordant diagnosis (p = 0.001). All cases of herpetic anterior uveitis (42.9% HIV+) tested PCR-/GWC+ while all cases of herpetic NAU tested PCR+/GWC- (83.3% HIV+). All rubella virus cases were PCR+/GWC+.

Conclusion: PCR is useful to diagnose herpetic NAU in HIV+ patients while GWC is useful to diagnose herpetic anterior uveitis.  相似文献   

45.
46.
47.
48.
Objective: Human epidermal growth factor receptor 2 (erbb2/HER2) overexpression, has now been implicatedin advanced gastric and gastroesophageal junction cancers. The study was conducted to determine the rate of HER2positivity in patients with locally advanced or metastatic gastric and gastroesophageal adenocarcinoma in North-EastIndia and to assess the impact of various demographic and clinical parameters on HER2 positivity. Methods: A total of68 patients of age >18 years of gastric and gastroesophageal adenocarcinoma diagnosed on histopathological examinationfrom September 2016 to February 2018 at Dr B Borooah Cancer Institute, Assam were enrolled for the observational(epidemiological) study. All patients were subjected to the HER2 immunohistochemistry test using a FDA-approved,standardized test kit. HER2 expression was correlated with various demographic and clinicopathological parameters.Results: The overall rate of HER2 positivity in the population studied was 56% (n=38). The rate was non-significantlyhigher in male, older age group (>60 years) and Hindu population. Similarly, HER2 positivity rate was higher in patientswith well differentiated histology and was more common in patients with stage II and III diseases, but neither of theassociations is statistically significant. HER2 positivity rate was significantly higher in proximal and in GEJ tumours(56% versus 44%, P=0.002). Conclusion: HER2 overexpression was evident in 56% of the North-East Indian patientswith locally advanced and metastatic gastric and gastroesophageal adenocarcinoma. The overexpression correlatedsignificantly with primary tumour site. Routine testing of gastric and gastroesophageal tumours for HER2 expressionis recommended to provide a therapeutic advantage in Indian patients.  相似文献   
49.

Objective

To examine whether a healthy weight intervention embedded in the Parents as Teachers (PAT) home visiting program, which was previously found to improve mothers’ body mass index (BMI) and obesity-related behaviors, changed the BMI of preschool children or maternal feeding practices.

Methods

This stratified randomized trial included preschool-aged children at risk for overweight whose mothers were overweight or had obesity (n?=?179). The Healthy Eating and Active Living Taught at Home (HEALTH) intervention was based on the Diabetes Prevention Program. Differences were examined using repeated-measures mixed-ANOVA models.

Results

Compared with PAT usual care, the HEALTH intervention had no effect on children's BMI or maternal feeding practices. However, combined analyses showed that children's BMI percentile decreased (P??=?.007), BMI z-scores were maintained (P??=?.19), and 3 of 8 feeding practices improved over time (P < .05).

Conclusions and Implications

Additional research is needed to assess the effectiveness of PAT to prevent preschool-age obesity using rigorous designs (eg, group-randomized trials) and to identify its active components. HEALTH is ready to be scaled up to prevent maternal weight gain through embedding within the national PAT program.  相似文献   
50.
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