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   717篇
  免费   49篇
  国内免费   1篇
耳鼻咽喉   13篇
儿科学   7篇
妇产科学   6篇
基础医学   128篇
口腔科学   31篇
临床医学   57篇
内科学   164篇
皮肤病学   8篇
神经病学   118篇
特种医学   23篇
外科学   89篇
预防医学   52篇
眼科学   7篇
药学   32篇
中国医学   1篇
肿瘤学   31篇
  2023年   3篇
  2022年   5篇
  2021年   8篇
  2020年   3篇
  2019年   7篇
  2018年   14篇
  2017年   6篇
  2016年   16篇
  2015年   21篇
  2014年   23篇
  2013年   37篇
  2012年   48篇
  2011年   35篇
  2010年   26篇
  2009年   24篇
  2008年   40篇
  2007年   47篇
  2006年   40篇
  2005年   39篇
  2004年   54篇
  2003年   48篇
  2002年   47篇
  2001年   8篇
  2000年   19篇
  1999年   10篇
  1998年   7篇
  1997年   8篇
  1996年   10篇
  1995年   9篇
  1994年   5篇
  1993年   7篇
  1992年   8篇
  1991年   13篇
  1990年   13篇
  1989年   6篇
  1988年   5篇
  1987年   3篇
  1985年   8篇
  1984年   3篇
  1983年   6篇
  1982年   2篇
  1980年   3篇
  1979年   3篇
  1977年   2篇
  1976年   3篇
  1975年   3篇
  1974年   2篇
  1972年   3篇
  1967年   2篇
  1965年   1篇
排序方式: 共有767条查询结果,搜索用时 31 毫秒
1.
Prostate-specific antigen (PSA)-based screening for prostate cancer (PCa) can reduce PCa mortality, but also involves overdetection of low-risk disease with potential adverse effects. We evaluated PCa incidence among men with PSA below 3 ng/mL and no PCa diagnosis at the first screening round of the Finnish Randomized Study of Screening for PCa. Follow-up started at the first screening attendance and ended at PCa diagnosis, emigration, death or the common closing date (December 2016), whichever came first. Cox regression analysis was used to estimate hazard ratios and their confidence intervals (CI). Among men with PSA <3 ng/mL, cumulative PCa incidence was 9.1% after 17.6 years median follow-up. Cumulative incidence was 3.6% among men with baseline PSA 0 to 0.99 ng/mL, 11.5% in those with PSA 1.0 to 1.99 ng/mL and 25.7% among men with PSA 2 to 2.99 ng/mL (hazard ratio 9.0, 95% CI: 7.9-10.2 for the latter). The differences by PSA level were most striking for low-risk disease based on Gleason score and EAU risk group. PSA values <1 ng/mL indicate a very low 20-year risk, while at PSA 2 to 2.99 ng/mL risks are materially higher, with 4- to 5-fold risk for aggressive disease. Using risk-stratification and appropriate rescreening intervals will reduce screening intensity and overdetection. Using cumulative incidence of clinically significant PCa (csPCa) as the criterion, rescreening intervals could range from approximately 3 years for men with initial PSA 2 to 2.99 ng/mL, 6 years for men with PSA 1 to 1.99 ng/mL to 10 years for men with PSA <1 ng/mL.  相似文献   
2.
3.
4.
Extracts of cell sonicates of Bacteroides gingivalis were shown to contain proteo-lytic enzymes capable of degrading connective tissue proteins. In this study, neutral proteolytic enzymes, i.e. collagenase and a trypsin-like protease, were isolated. The trypsin-like protease was readily separated from collagenase by affinity chromatography on Benzamidine-Sepharose. Proteases were further purified by gel filtration on Sephacryl S-200; apparent molecular weights of 35 kDa and 70 kDa were obtained for a trypsin-like protease and collagenase, respectively. Further characterization of the potent trypsin-like protease showed that the enzyme was inhibited by serine protease inhibitors phenylmethylsulfonyl fluoride and benzamidine and by metalloprotease inhibitor EDTA, as well as ascorbic acid. Activation of the enzyme was observed with reducing agents and human serum. The trypsin-like protease was found to be capable of degrading native type IV collagen and denatured type I collagen but not native type I collagen. Thus, we conclude that in addition to collagenase a potent trypsin-like protease from Bacteroides gingivalis may be involved in the etiopathogenesis of periodontal disease. Since the trypsin-like protease is able to degrade the basement membrane collagen (type IV) in the presence of human serum, this enzyme may be a potent virulence factor of Bacteroides gingivalis in relation to invasiveness and connective tissue destruction.  相似文献   
5.
6.
7.
To analyse the epidemiology of burns in Finland, a comprehensive study was conducted among all hospitalized burn patients between 1980 and 2010. All patients with burn injury as the main diagnosis, 36 305 cases in total, treated in the public and private sectors, were included.Patient data were obtained from the Finnish Hospital Discharge Register (FHDR). The incidence of hospitalized injuries declined from over 30 to 17 per 100 000 persons. Men were at higher risk than women in all age groups. Children aged under ten years were overrepresented throughout the period and the highest incidence was found among one year old boys. The median total length of stay shortened from seven days in 1980–1995 to five days in 1996–2010. The annual number of hospitalized patients is recently under 1000 cases (17/100 000). The male predominance (70%) did not change but the age group with the most injuries shifted from 20–39 years to 40–59 years. Injuries were most common during the summer months.This study of all hospitalized burn injuries of one entire country shows similar tendency of diminishing numbers and rising age of burn victims as in other western countries. The FHDR is a reliable source of data in epidemiological studies but precise recording of E- and N-codes in the registry would enable the accurate analysis of types and extent of injury.  相似文献   
8.
9.
Walter  S. D.  Hu  Jiarui  Talala  Kirsi  Tammela  Teuvo  Taari  Kimmo  Auvinen  Anssi 《Cancer causes & control : CCC》2021,32(11):1299-1313
Cancer Causes & Control - Screening for prostate cancer may have limited impact on decreasing prostate cancer-related mortality. A major disadvantage is overdiagnosis, whereby lesions are...  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