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   38629篇
  免费   3076篇
  国内免费   82篇
耳鼻咽喉   294篇
儿科学   1713篇
妇产科学   1188篇
基础医学   5236篇
口腔科学   413篇
临床医学   4679篇
内科学   7064篇
皮肤病学   688篇
神经病学   4549篇
特种医学   729篇
外科学   3769篇
综合类   363篇
现状与发展   1篇
一般理论   75篇
预防医学   5244篇
眼科学   598篇
药学   2528篇
中国医学   35篇
肿瘤学   2621篇
  2024年   81篇
  2023年   618篇
  2022年   991篇
  2021年   1955篇
  2020年   1157篇
  2019年   1675篇
  2018年   1882篇
  2017年   1272篇
  2016年   1445篇
  2015年   1497篇
  2014年   1966篇
  2013年   2466篇
  2012年   3573篇
  2011年   3459篇
  2010年   1731篇
  2009年   1483篇
  2008年   2285篇
  2007年   2370篇
  2006年   2017篇
  2005年   1842篇
  2004年   1576篇
  2003年   1302篇
  2002年   1180篇
  2001年   156篇
  2000年   110篇
  1999年   184篇
  1998年   237篇
  1997年   139篇
  1996年   119篇
  1995年   115篇
  1994年   112篇
  1993年   98篇
  1992年   55篇
  1991年   57篇
  1990年   48篇
  1989年   39篇
  1988年   32篇
  1987年   30篇
  1986年   34篇
  1985年   36篇
  1984年   45篇
  1983年   34篇
  1982年   34篇
  1981年   33篇
  1980年   34篇
  1979年   29篇
  1978年   23篇
  1977年   13篇
  1973年   14篇
  1972年   16篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
23.
BACKGROUND: The HOXA1 gene plays a major role in brainstem and cranial morphogenesis. The G allele of the HOXA1 A218G polymorphism has been previously found associated with autism. METHODS: We performed case-control and family-based association analyses, contrasting 127 autistic patients with 174 ethnically matched controls, and assessing for allelic transmission disequilibrium in 189 complete trios. RESULTS: A, and not G, alleles were associated with autism using both case-control (chi(2) = 8.96 and 5.71, 1 df, p <.005 and <.025 for genotypes and alleles, respectively), and family-based (transmission/disequilibrium test chi(2) = 8.80, 1 df, p <.005) association analyses. The head circumference of 31 patients carrying one or two copies of the G allele displayed significantly larger median values (95.0th vs. 82.5th percentile, p <.05) and dramatically reduced interindividual variability (p <.0001), compared with 166 patients carrying the A/A genotype. CONCLUSIONS: The HOXA1 A218G polymorphism explains approximately 5% of the variance in the head circumference of autistic patients and represents to our knowledge the first known gene variant providing sizable contributions to cranial morphology. The disease specificity of this finding is currently being investigated. Nonreplications in genetic linkage/association studies could partly stem from the dyshomogeneous distribution of an endophenotype morphologically defined by cranial circumference.  相似文献   
24.
25.
PURPOSE: This study aims to determine the effect of loss of breast cancer metastasis suppressor 1 (BRMS1) protein expression on disease-free survival in breast cancer patients stratified by estrogen receptor (ER), progesterone receptor (PR), or HER2 status, and to determine whether loss of BRMS1 protein expression correlated with genomic copy number changes. EXPERIMENTAL DESIGN: A tissue microarray immunohistochemical analysis was done on tumors of 238 newly diagnosed breast cancer patients who underwent surgery at the Cleveland Clinic between January 1, 1995 and December 31, 1996, and a comparison was made with 5-year clinical follow-up data. Genomic copy number changes were determined by array-based comparative genomic hybridization in 47 breast cancer cases from this population and compared with BRMS1 staining. RESULTS: BRMS1 protein expression was lost in nearly 25% of cases. Patients with tumors that were PR negative (P=0.006) or HER2 positive (P=0.039) and <50 years old at diagnosis (P=0.02) were more likely to be BRMS1 negative. No overall correlation between BRMS1 staining and disease-free survival was observed. A significant correlation, however, was seen between loss of BRMS1 protein expression and reduced disease-free survival when stratified by either loss of ER (P=0.008) or PR (P=0.029) or HER2 overexpression (P=0.026). Overall, there was poor correlation between BRMS1 protein staining and copy number status. CONCLUSIONS: These data suggest a mechanistic relationship between BRMS1 expression, hormone receptor status, and HER2 growth factor. BRMS1 staining could potentially be used in patient stratification in conjunction with other prognostic markers. Further, mechanisms other than genomic deletion account for loss of BRMS1 gene expression in breast tumors.  相似文献   
26.

Background  

Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods.  相似文献   
27.
28.
29.
Grief     
  相似文献   
30.
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