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   148257篇
  免费   7372篇
  国内免费   179篇
耳鼻咽喉   2341篇
儿科学   5075篇
妇产科学   3388篇
基础医学   22694篇
口腔科学   4547篇
临床医学   12532篇
内科学   27422篇
皮肤病学   4267篇
神经病学   14790篇
特种医学   6559篇
外科学   22257篇
综合类   665篇
一般理论   39篇
预防医学   8075篇
眼科学   3134篇
药学   10036篇
中国医学   225篇
肿瘤学   7762篇
  2023年   833篇
  2022年   508篇
  2021年   1364篇
  2020年   1253篇
  2019年   1566篇
  2018年   3267篇
  2017年   2703篇
  2016年   3471篇
  2015年   3056篇
  2014年   3369篇
  2013年   5896篇
  2012年   7783篇
  2011年   8639篇
  2010年   4834篇
  2009年   3286篇
  2008年   8694篇
  2007年   9168篇
  2006年   8818篇
  2005年   8711篇
  2004年   8175篇
  2003年   8181篇
  2002年   8031篇
  2001年   5395篇
  2000年   6822篇
  1999年   3816篇
  1998年   1549篇
  1997年   1303篇
  1996年   1055篇
  1995年   856篇
  1994年   838篇
  1993年   789篇
  1992年   776篇
  1991年   675篇
  1990年   676篇
  1989年   723篇
  1988年   600篇
  1987年   678篇
  1986年   582篇
  1985年   778篇
  1984年   703篇
  1983年   603篇
  1982年   625篇
  1981年   588篇
  1980年   538篇
  1979年   541篇
  1978年   490篇
  1977年   505篇
  1976年   428篇
  1975年   447篇
  1974年   424篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
Graefe's Archive for Clinical and Experimental Ophthalmology -  相似文献   
14.
15.
Objectives: The steeling effect suggests that early-life adversity can have a beneficial impact later in life. However, little is known about its underlying mechanisms and long-term outcomes . The study aimed to examine the role of early-life adversity (ELA) on successful aging, and whether this relationship can be explained by mental and physical health.

Method: Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (Mage = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted.

Results: Significant inverse U-shaped associations were found between ELA and iQoL (β = ?.59, p = .005) and between ELA and mental health (β = ?.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = ?.84, BCa CI [?1.66, ?.27]).

Conclusion: Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity.  相似文献   

16.

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   
17.

Background

The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies.

Methods

Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30?days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12?months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period.

Results

Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race.

Conclusions

No safety concerns arose, supporting the favorable benefit-risk profile of RZV.  相似文献   
18.
19.
We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa’s environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly.  相似文献   
20.
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