收费全文 | 35937篇 |
免费 | 3404篇 |
国内免费 | 1309篇 |
耳鼻咽喉 | 573篇 |
儿科学 | 936篇 |
妇产科学 | 397篇 |
基础医学 | 3573篇 |
口腔科学 | 332篇 |
临床医学 | 4250篇 |
内科学 | 5481篇 |
皮肤病学 | 208篇 |
神经病学 | 7293篇 |
特种医学 | 1145篇 |
外国民族医学 | 1篇 |
外科学 | 4093篇 |
综合类 | 4239篇 |
预防医学 | 2120篇 |
眼科学 | 798篇 |
药学 | 2494篇 |
19篇 | |
中国医学 | 1215篇 |
肿瘤学 | 1483篇 |
2024年 | 149篇 |
2023年 | 717篇 |
2022年 | 1266篇 |
2021年 | 1697篇 |
2020年 | 1624篇 |
2019年 | 1690篇 |
2018年 | 1693篇 |
2017年 | 1670篇 |
2016年 | 1534篇 |
2015年 | 1419篇 |
2014年 | 2539篇 |
2013年 | 2919篇 |
2012年 | 2163篇 |
2011年 | 2256篇 |
2010年 | 1864篇 |
2009年 | 1852篇 |
2008年 | 1913篇 |
2007年 | 1856篇 |
2006年 | 1574篇 |
2005年 | 1330篇 |
2004年 | 1050篇 |
2003年 | 941篇 |
2002年 | 785篇 |
2001年 | 581篇 |
2000年 | 454篇 |
1999年 | 363篇 |
1998年 | 282篇 |
1997年 | 291篇 |
1996年 | 250篇 |
1995年 | 225篇 |
1994年 | 198篇 |
1993年 | 180篇 |
1992年 | 161篇 |
1991年 | 138篇 |
1990年 | 106篇 |
1989年 | 97篇 |
1988年 | 84篇 |
1987年 | 83篇 |
1986年 | 81篇 |
1985年 | 85篇 |
1984年 | 81篇 |
1983年 | 44篇 |
1982年 | 58篇 |
1981年 | 42篇 |
1980年 | 49篇 |
1979年 | 39篇 |
1978年 | 27篇 |
1977年 | 32篇 |
1976年 | 31篇 |
1975年 | 19篇 |
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Objective
The advantage of arteriovenous fistulas (AVFs) in older patients requiring dialysis is controversial. We reviewed our vascular access experience in patients ≥70 years of age (older group) compared with younger patients.Methods
We analyzed consecutive patients who underwent access surgery between 2013 and 2016. Primary success (PS) and primary patency (PP) data were analyzed between the older and younger groups before and after propensity score matching of the patients' characteristics and access composition. PS was defined as the achievement of access function that was amenable to two sessions of successful cannulation without early occlusion or maturation failure requiring revision. PP was defined as the time with uninterrupted patency without intervention.Results
A total of 594 consecutive accesses were created among 563 patients, of whom 119 were allocated into each group after propensity score matching. In the whole cohort, 193 accesses (32.5%) were performed in older patients. AVFs were performed in 130 (67.4%) older patients and 293 (73.1%) younger patients. Regarding AVFs, the PS rate (83.6% in the older group vs 94.3% in the younger group; P = .001) and the overall PP at 6 and 12 months (73.1% and 57.1%, respectively, in the older group vs 86.7% and 77.7%, respectively, in the younger group; P = .009) were lower in the older group than in the younger group. However, no differences were found in the PS and PP rates for arteriovenous grafts between groups. Regarding the AVF location, the PS rate for forearm AVFs was significantly lower in the older group than in the younger group (76% vs 93%; P < .001); however, the PS rate of the upper arm was not different between the groups (94% vs 97%; P = .425). In the patients with PS, the PP rate of AVFs was similar between the two groups. In the older group with forearm AVFs, the median diameter of the radial artery was larger in the patients with PS than in the patients without PS (2.20 mm with PS vs 2.00 mm without PS; P = .008). The propensity score matching results demonstrated similar trends for the whole cohort, with lower PS (P = .042) and PP rates (P = .023) for AVF in the older group.Conclusions
The outcomes after AVF were poorer in the older group than in the younger group, which was primarily due to unsatisfactory outcomes in patients with forearm AVFs. Thus, stricter criteria, especially regarding the radial artery diameter, should be applied for forearm AVFs in older patients, and additional research is necessary to delineate the risk factors for primary failure. 相似文献Material and methods: original research studies were searched from seven databases (MEDLINE, EMBASE, CENTRAL, CINAHL, SCOPUS, PEDro and PubMed). Subsequently, two independent reviewers screened the titles and abstracts followed by full-text reviews to assess the studies' eligibility.
Results: eleven studies met the inclusion criteria and had data abstracted and quality assessed. Methodology varied considerably and yet cognitive tasks resulted in the ΔO2Hb increasing in 8 of the 11 and ΔHHb decreasing in 8 of 8 studies that reported this outcome. The cognitive tasks from 10 of the 11 studies were classified as “Working Memory” and “Verbal Fluency Tasks”.
Conclusions: although, the data comparison was challenging provided the heterogeneity in methodology, the results across studies were similar. 相似文献