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   1004814篇
  免费   75711篇
  国内免费   2619篇
耳鼻咽喉   13008篇
儿科学   34669篇
妇产科学   28666篇
基础医学   146084篇
口腔科学   28085篇
临床医学   91082篇
内科学   194898篇
皮肤病学   22982篇
神经病学   79793篇
特种医学   38680篇
外国民族医学   305篇
外科学   150547篇
综合类   24050篇
一般理论   396篇
预防医学   78644篇
眼科学   22760篇
药学   72235篇
  3篇
中国医学   2032篇
肿瘤学   54225篇
  2018年   10662篇
  2017年   8328篇
  2016年   9461篇
  2015年   10708篇
  2014年   14567篇
  2013年   22257篇
  2012年   29342篇
  2011年   31208篇
  2010年   18689篇
  2009年   17611篇
  2008年   29100篇
  2007年   30821篇
  2006年   31310篇
  2005年   29969篇
  2004年   29249篇
  2003年   28088篇
  2002年   27116篇
  2001年   47143篇
  2000年   48259篇
  1999年   40478篇
  1998年   11253篇
  1997年   10165篇
  1996年   10213篇
  1995年   9831篇
  1994年   9150篇
  1993年   8534篇
  1992年   32417篇
  1991年   31638篇
  1990年   31196篇
  1989年   30024篇
  1988年   27320篇
  1987年   27480篇
  1986年   25586篇
  1985年   24744篇
  1984年   18468篇
  1983年   15592篇
  1982年   9343篇
  1981年   8425篇
  1979年   16930篇
  1978年   12282篇
  1977年   10357篇
  1976年   9794篇
  1975年   10218篇
  1974年   12363篇
  1973年   11884篇
  1972年   10930篇
  1971年   10166篇
  1970年   9416篇
  1969年   8760篇
  1968年   8138篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.

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   
10.

Objective

To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines in infants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6?months of life.

Methods

Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.

Results

Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.

Conclusions

There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.

Policy implications

Our review suggests a need for improved surveillance of immunization status in special populations of infants, as well as a need for standardization of reporting practices.  相似文献   
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