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   392676篇
  免费   25601篇
  国内免费   2885篇
耳鼻咽喉   5304篇
儿科学   8428篇
妇产科学   10337篇
基础医学   55016篇
口腔科学   12137篇
临床医学   30990篇
内科学   81912篇
皮肤病学   8777篇
神经病学   28446篇
特种医学   14501篇
外国民族医学   82篇
外科学   62827篇
综合类   10017篇
现状与发展   1篇
一般理论   65篇
预防医学   17805篇
眼科学   9886篇
药学   32077篇
  1篇
中国医学   2252篇
肿瘤学   30301篇
  2021年   2851篇
  2019年   2938篇
  2018年   4782篇
  2017年   3643篇
  2016年   3804篇
  2015年   4298篇
  2014年   6078篇
  2013年   7858篇
  2012年   10769篇
  2011年   11012篇
  2010年   6637篇
  2009年   6205篇
  2008年   10147篇
  2007年   11007篇
  2006年   10870篇
  2005年   9961篇
  2004年   9560篇
  2003年   9215篇
  2002年   8900篇
  2001年   28643篇
  2000年   29177篇
  1999年   24047篇
  1998年   5373篇
  1997年   4412篇
  1996年   3958篇
  1995年   3597篇
  1994年   3224篇
  1993年   2943篇
  1992年   16321篇
  1991年   15029篇
  1990年   14368篇
  1989年   14195篇
  1988年   12786篇
  1987年   12248篇
  1986年   11279篇
  1985年   10512篇
  1984年   7058篇
  1983年   5705篇
  1982年   2780篇
  1979年   5583篇
  1978年   3432篇
  1977年   3054篇
  1975年   2683篇
  1974年   3124篇
  1973年   2915篇
  1972年   2890篇
  1971年   2835篇
  1970年   2571篇
  1969年   2590篇
  1968年   2319篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
Harinakshi Sanikini  David C. Muller  Marisa Sophiea  Sabina Rinaldi  Antonio Agudo  Eric J. Duell  Elisabete Weiderpass  Kim Overvad  Anne Tjønneland  Jytte Halkjær  Marie-Christine Boutron-Ruault  Franck Carbonnel  Iris Cervenka  Heiner Boeing  Rudolf Kaaks  Tilman Kühn  Antonia Trichopoulou  Georgia Martimianaki  Anna Karakatsani  Valeria Pala  Domenico Palli  Amalia Mattiello  Rosario Tumino  Carlotta Sacerdote  Guri Skeie  Charlotta Rylander  María-Dolores Chirlaque López  Maria-Jose Sánchez  Eva Ardanaz  Sara Regnér  Tanja Stocks  Bas Bueno-de-Mesquita  Roel C.H. Vermeulen  Dagfinn Aune  Tammy Y.N. Tong  Nathalie Kliemann  Neil Murphy  Marc Chadeau-Hyam  Marc J. Gunter  Amanda J. Cross 《International journal of cancer. Journal international du cancer》2020,146(4):929-942
Obesity has been associated with upper gastrointestinal cancers; however, there are limited prospective data on associations by subtype/subsite. Obesity can impact hormonal factors, which have been hypothesized to play a role in these cancers. We investigated anthropometric and reproductive factors in relation to esophageal and gastric cancer by subtype and subsite for 476,160 participants from the European Prospective Investigation into Cancer and Nutrition cohort. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox models. During a mean follow-up of 14 years, 220 esophageal adenocarcinomas (EA), 195 esophageal squamous cell carcinomas, 243 gastric cardia (GC) and 373 gastric noncardia (GNC) cancers were diagnosed. Body mass index (BMI) was associated with EA in men (BMI ≥30 vs. 18.5–25 kg/m2: HR = 1.94, 95% CI: 1.25–3.03) and women (HR = 2.66, 95% CI: 1.15–6.19); however, adjustment for waist-to-hip ratio (WHR) attenuated these associations. After mutual adjustment for BMI and HC, respectively, WHR and waist circumference (WC) were associated with EA in men (HR = 3.47, 95% CI: 1.99–6.06 for WHR >0.96 vs. <0.91; HR = 2.67, 95% CI: 1.52–4.72 for WC >98 vs. <90 cm) and women (HR = 4.40, 95% CI: 1.35–14.33 for WHR >0.82 vs. <0.76; HR = 5.67, 95% CI: 1.76–18.26 for WC >84 vs. <74 cm). WHR was also positively associated with GC in women, and WC was positively associated with GC in men. Inverse associations were observed between parity and EA (HR = 0.38, 95% CI: 0.14–0.99; >2 vs. 0) and age at first pregnancy and GNC (HR = 0.54, 95% CI: 0.32–0.91; >26 vs. <22 years); whereas bilateral ovariectomy was positively associated with GNC (HR = 1.87, 95% CI: 1.04–3.36). These findings support a role for hormonal pathways in upper gastrointestinal cancers.  相似文献   
44.
45.
46.
47.
BackgroundWomen suffering from kidney disease are more prone to fertility problems, due to uremia. Fortunately, their fertility rate increases dramatically after renal transplantation. This study analyzes the predictors/risk factors of successful pregnancy with live birth outcome while presenting an overview of the 7-year experience of a single center.MethodsThis retrospective cohort study includes 239 women of reproductive age (18–40 years) who underwent renal transplantation in a tertiary Turkish clinic between October 1, 2011, and August 24, 2017. The subjects were invited to take part in a survey questioning their obstetric characteristics and they were assessed in 2 groups: fertile and infertile. Multivariable linear regression analysis was conducted to determine the predictors of a successful pregnancy.ResultsThirty-five 35 patients wished to become pregnant: 12 got pregnant spontaneously, while 21 failed to become pregnant (spontaneously). The mean age of the patients at the survey was 34 ± 7. Regular menstrual cycles after renal transplantation, tacrolimus-mycophenolate mofetil maintenance protocol, and age at transplantation were found to be predictors of spontaneous pregnancy. The duration of peritoneal dialysis was significantly longer in the infertile group (48 vs 12 months).ConclusionEnd-stage renal disease's negative impacts, including menstrual abnormality and fertility problems, can be overcome by successful kidney transplantation with appropriate immunosuppression. Minimizing the duration of peritoneal dialysis, particularly in patients who desire future fertility, may be accepted as a logical management strategy.  相似文献   
48.
49.
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