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   558篇
  免费   46篇
  国内免费   3篇
耳鼻咽喉   5篇
儿科学   16篇
妇产科学   5篇
基础医学   109篇
口腔科学   26篇
临床医学   79篇
内科学   96篇
皮肤病学   16篇
神经病学   35篇
特种医学   37篇
外科学   69篇
综合类   4篇
预防医学   31篇
药学   36篇
中国医学   1篇
肿瘤学   42篇
  2021年   7篇
  2020年   6篇
  2019年   7篇
  2018年   11篇
  2017年   8篇
  2016年   7篇
  2015年   14篇
  2014年   12篇
  2013年   20篇
  2012年   24篇
  2011年   21篇
  2010年   22篇
  2009年   16篇
  2008年   29篇
  2007年   19篇
  2006年   25篇
  2005年   18篇
  2004年   23篇
  2003年   16篇
  2002年   15篇
  2001年   12篇
  2000年   18篇
  1999年   7篇
  1998年   14篇
  1997年   15篇
  1996年   17篇
  1995年   8篇
  1994年   8篇
  1993年   6篇
  1992年   14篇
  1991年   13篇
  1990年   11篇
  1989年   17篇
  1988年   10篇
  1987年   10篇
  1986年   9篇
  1984年   4篇
  1983年   8篇
  1980年   4篇
  1979年   7篇
  1976年   4篇
  1974年   7篇
  1973年   4篇
  1972年   6篇
  1970年   3篇
  1969年   3篇
  1968年   3篇
  1967年   5篇
  1966年   6篇
  1965年   4篇
排序方式: 共有607条查询结果,搜索用时 31 毫秒
1.
2.
3.
We conducted a multicenter, double-blind, placebo-controlled randomized trial of aspirin treatment (324 mg in buffered solution daily) for 12 weeks in 1266 men with unstable angina (625 taking aspirin and 641 placebo). The principal end points were death and acute myocardial infarction diagnosed by the presence of creatine kinase MB or pathologic Q-wave changes on electrocardiograms. The incidence of death or acute myocardial infarction was 51 per cent lower in the aspirin group than in the placebo group: 31 patients (5.0 per cent) as compared with 65 (10.1 per cent); P = 0.0005. Nonfatal acute myocardial infarction was 51 per cent lower in the aspirin group: 21 patients (3.4 per cent) as compared with 44 (6.9 per cent); P = 0.005. The reduction in mortality in the aspirin group was also 51 per cent--10 patients (1.6 per cent) as compared with 21 (3.3 per cent)--although it was not statistically significant; P = 0.054. There was no difference in gastrointestinal symptoms or evidence of blood loss between the treatment and control groups. Our data show that aspirin has a protective effect against acute myocardial infarction in men with unstable angina, and they suggest a similar effect on mortality.  相似文献   
4.
5.
乳腺管状小叶癌(Tubulolobular carcinoma,TLC)最初是被作为小叶癌的管状变型。作者总结了27例TLC的组织学、免疫表型和临床特征,并与纯小管癌和经典型小叶癌进行了比较。此组患者年龄43-79岁(中位年龄60岁)。1例双侧乳腺受累,5例病变为多灶性。肿瘤直径0.5-2.5cm,色灰褐,质硬。组织学观察:TLC的肿瘤细胞形成管状和条索状两种结构模式并相互混杂,且两者比例相当(统称为管状小叶模式)。  相似文献   
6.
7.
8.
BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) is a disease of intense eosinophilic inflammation that can produce fibrosis, hyperplasia, and remodeling. OBJECTIVE: To investigate the usefulness of quantifying severity of chronic hyperplastic eosinophilic sinusitis in predicting the presence of AERD. METHODS: Data were compared between asthmatic patients who reported exacerbations after aspirin ingestion and those who did not. The primary outcome measure was severity of sinusitis using a validated computed tomography (CT) scan-based scoring system. Indices of lower airway remodeling and other markers of inflammation were also evaluated. RESULTS: Twenty-one patients with AERD were compared with 19 patients with aspirin-tolerant asthma (ATA). Patients were well matched for asthma severity as shown by their similar lung function as measured by postbronchodilator forced expiratory volume in 1 second. Patients with AERD were distinguished by their sinus CT scores (AERD patients: 16.9; 95% confidence interval [CI], 13.4-21.3; ATA patients: 6.2; 95% CI, 4.2-9.1; P < .001), and they were considerably more likely to have nasal polyps (AERD patients: 90%; ATA patients: 26%; P < .001). In addition, AERD patients demonstrated increased total lung capacity (AERD patients: 107.9%; 95% CI, 99.9%-117.6%; ATA patients: 98.0%; 95% CI, 93.7%-102.5%; P = .05), reflecting a trend toward increased air trapping. No significant differences occurred in diffusing capacity, exhaled nitric oxide, eosinophilia, or exhaled breath condensate pH. CONCLUSIONS: AERD can be distinguished from ATA by the extent of hyperplasia on CT scan and the presence of nasal polyps. We hypothesize that AERD represents a remodeling process that affects both the upper and lower airways.  相似文献   
9.
Germline mutations of the CDKN2 gene in UK melanoma families   总被引:4,自引:1,他引:4  
Germline mutations in CDKN2 on chromosome 9p21, which codes for the cyclin D kinase inhibitor p16, and more rarely, mutations in the gene coding for CDK4, the protein to which p16 binds, underlie susceptibility in some melanoma families. We have sequenced all exons of CDKN2 and analysed the CDK4 gene for mutations in 27 UK families showing evidence of predisposition to melanoma. Five different germline mutations in CDKN2 were found in six families. Three of the mutations (Met53Ile, Arg24Pro and 23ins24) have been reported previously. We have identified two novel CDKN2 mutations (88delG and Ala118Thr) which are likely to be associated with the development of melanoma, because of their co-segregation with the disease and their likely functional effect on the CDKN2 protein. In binding assays the protein expressed from the previously described mutation, Met53Ile, did not bind to CDK4/CDK6, confirming its role as a causal mutation in the development of melanoma. Ala118Thr appeared to be functional in this assay. Arg24Pro appeared to bind to CDK6, but not to CDK4. No mutations were detected in exon 2 of CDK4, suggesting that causal mutations in this gene are uncommon. The penetrance of these mutant CDKN2 genes is not yet established, nor is the risk of non-melanoma cancer to gene carriers.   相似文献   
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