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   147800篇
  免费   7927篇
  国内免费   127篇
耳鼻咽喉   2328篇
儿科学   5075篇
妇产科学   3394篇
基础医学   21792篇
口腔科学   4630篇
临床医学   12593篇
内科学   26773篇
皮肤病学   4069篇
神经病学   15467篇
特种医学   6371篇
外科学   22745篇
综合类   738篇
一般理论   61篇
预防医学   8694篇
眼科学   3103篇
药学   10103篇
中国医学   223篇
肿瘤学   7695篇
  2023年   854篇
  2022年   558篇
  2021年   1457篇
  2020年   1323篇
  2019年   1665篇
  2018年   3263篇
  2017年   2742篇
  2016年   3500篇
  2015年   3034篇
  2014年   3487篇
  2013年   6021篇
  2012年   7865篇
  2011年   8842篇
  2010年   4976篇
  2009年   3435篇
  2008年   8826篇
  2007年   9200篇
  2006年   8895篇
  2005年   8839篇
  2004年   8291篇
  2003年   8298篇
  2002年   8143篇
  2001年   5343篇
  2000年   6761篇
  1999年   3753篇
  1998年   1595篇
  1997年   1292篇
  1996年   1029篇
  1995年   864篇
  1994年   833篇
  1993年   777篇
  1992年   766篇
  1991年   635篇
  1990年   604篇
  1989年   643篇
  1988年   556篇
  1987年   612篇
  1986年   509篇
  1985年   724篇
  1984年   704篇
  1983年   600篇
  1982年   638篇
  1981年   593篇
  1980年   568篇
  1979年   511篇
  1978年   464篇
  1977年   493篇
  1976年   421篇
  1975年   421篇
  1974年   393篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
21.

Objective

Low psoas muscle area is shown to be an indicator for worse postoperative outcome in patients undergoing vascular surgical. Additionally, it has been associated with longer durations of hospital stay in patients with cancer who undergo surgery and subsequently greater health care costs in Europe and the United States. We sought to evaluate this effect on hospital expenditure for patients undergoing vascular repair in a health care system with universal access.

Methods

Skeletal muscle mass was assessed on preoperative abdominal computed tomography scans of patients undergoing open aortic aneurysm repair in a retrospective fashion. The skeletal muscle index (SMI) was used to define low muscle mass. Health care costs were obtained for all patients and the relationship between a low SMI and higher costs was explored using linear regression and cross-sectional analysis.

Results

We included 156 patients (81.5% male) with a median age of 72 years undergoing elective surgery for infrarenal abdominal aortic aneurysm in this analysis. The median SMI for patients with low skeletal muscle mass was 53.21 cm2/kg and for patients without, 70.07 cm2/kg. Hospital duration of stay was 2 days longer in patients with low skeletal muscle mass as compared with patients with normal (14 days vs 11 days; P = .001), as was duration of intensive care stay (3 days vs 1 day; P = .01). The median overall hospital costs were €10,460 higher for patients with a low SMI as compared with patients with a normal physical constitution (€53,739 [interquartile range, €45,007-€62,471] vs €43,279 [interquartile range, €39,509-€47,049]; P = .001). After confounder adjustment, a low SMI was associated with a 14.68% cost increase in overall hospital costs, for a cost increase of €6521.

Conclusions

Low skeletal muscle mass is independently associated with higher hospital as well as intensive care costs in patients undergoing elective aortic aneurysm repair. Strategies to reduce this risk factor are warranted for these patients.  相似文献   
22.
23.
24.
25.
26.
27.
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   
28.
29.
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