全文获取类型
| 收费全文 | 1395365篇 |
| 免费 | 100957篇 |
| 国内免费 | 1693篇 |
学科分类
| 医药卫生 | 1498015篇 |
出版年
| 2019年 | 11351篇 |
| 2018年 | 16305篇 |
| 2017年 | 12801篇 |
| 2016年 | 14439篇 |
| 2015年 | 15758篇 |
| 2014年 | 20963篇 |
| 2013年 | 32730篇 |
| 2012年 | 44329篇 |
| 2011年 | 47531篇 |
| 2010年 | 27291篇 |
| 2009年 | 25145篇 |
| 2008年 | 45298篇 |
| 2007年 | 48398篇 |
| 2006年 | 47773篇 |
| 2005年 | 46755篇 |
| 2004年 | 44747篇 |
| 2003年 | 43198篇 |
| 2002年 | 41928篇 |
| 2001年 | 60503篇 |
| 2000年 | 62604篇 |
| 1999年 | 51379篇 |
| 1998年 | 14750篇 |
| 1997年 | 13306篇 |
| 1996年 | 13509篇 |
| 1995年 | 12616篇 |
| 1994年 | 11778篇 |
| 1993年 | 11042篇 |
| 1992年 | 39022篇 |
| 1991年 | 38414篇 |
| 1990年 | 37167篇 |
| 1989年 | 35970篇 |
| 1988年 | 33299篇 |
| 1987年 | 32697篇 |
| 1986年 | 31074篇 |
| 1985年 | 29498篇 |
| 1984年 | 22611篇 |
| 1983年 | 19750篇 |
| 1982年 | 11923篇 |
| 1979年 | 21460篇 |
| 1978年 | 15845篇 |
| 1977年 | 13267篇 |
| 1976年 | 12248篇 |
| 1975年 | 13258篇 |
| 1974年 | 16018篇 |
| 1973年 | 15740篇 |
| 1972年 | 14851篇 |
| 1971年 | 13888篇 |
| 1970年 | 13103篇 |
| 1969年 | 12346篇 |
| 1968年 | 11499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.
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
8.
Stephan Koter Tina U. Cohnert Korbinian B. Hindermayr Jörg Lindenmann Maximilian Brückner Wolfgang K. Oswald Georg Werkgartner Doris Wagner 《Journal of vascular surgery》2019,69(4):1227-1232
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9.
Emma J. Walker Noni E. MacDonald Nehal Islam Nicole Le Saux Karina A. Top Deshayne B. Fell 《Vaccine》2019,37(13):1725-1735
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10.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
