全文获取类型
收费全文 | 7164篇 |
免费 | 703篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 116篇 |
儿科学 | 238篇 |
妇产科学 | 151篇 |
基础医学 | 885篇 |
口腔科学 | 294篇 |
临床医学 | 835篇 |
内科学 | 1398篇 |
皮肤病学 | 231篇 |
神经病学 | 483篇 |
特种医学 | 250篇 |
外科学 | 1207篇 |
综合类 | 190篇 |
一般理论 | 8篇 |
预防医学 | 717篇 |
眼科学 | 59篇 |
药学 | 501篇 |
中国医学 | 6篇 |
肿瘤学 | 312篇 |
出版年
2021年 | 102篇 |
2020年 | 64篇 |
2019年 | 122篇 |
2018年 | 110篇 |
2017年 | 82篇 |
2016年 | 112篇 |
2015年 | 131篇 |
2014年 | 161篇 |
2013年 | 261篇 |
2012年 | 314篇 |
2011年 | 298篇 |
2010年 | 204篇 |
2009年 | 165篇 |
2008年 | 254篇 |
2007年 | 251篇 |
2006年 | 320篇 |
2005年 | 282篇 |
2004年 | 234篇 |
2003年 | 267篇 |
2002年 | 243篇 |
2001年 | 214篇 |
2000年 | 233篇 |
1999年 | 209篇 |
1998年 | 102篇 |
1997年 | 104篇 |
1996年 | 95篇 |
1995年 | 96篇 |
1994年 | 70篇 |
1993年 | 89篇 |
1992年 | 172篇 |
1991年 | 169篇 |
1990年 | 163篇 |
1989年 | 174篇 |
1988年 | 160篇 |
1987年 | 135篇 |
1986年 | 145篇 |
1985年 | 150篇 |
1984年 | 113篇 |
1983年 | 71篇 |
1982年 | 63篇 |
1981年 | 71篇 |
1979年 | 83篇 |
1978年 | 79篇 |
1977年 | 66篇 |
1976年 | 70篇 |
1975年 | 50篇 |
1974年 | 62篇 |
1973年 | 76篇 |
1971年 | 56篇 |
1970年 | 56篇 |
排序方式: 共有7881条查询结果,搜索用时 125 毫秒
141.
142.
Tomasz Jazwiec Marcin Malinowski Haley Ferguson Jeremy Wodarek Nathan Quay Jared Bush Matthew Goehler Jessica Parker Manuel Rausch Tomasz A. Timek 《The Journal of thoracic and cardiovascular surgery》2021,161(4):e277-e286
ObjectiveTo investigate the effect of variable tricuspid annular reduction (TAR) on functional tricuspid regurgitation (FTR) and right ventricular (RV) dynamics in ovine tachycardia-induced cardiomyopathy.MethodsNine adult sheep underwent implantation of a pacemaker with an epicardial lead and were paced at 200 to 240 bpm until the development of biventricular dysfunction and functional TR was noted. During reoperation on cardiopulmonary bypass, 6 sonomicrometry crystals were placed around the tricuspid annulus (TA) and 14 were placed on the RV epicardium. Annuloplasty suture was placed around the TA and externalized to an epicardial tourniquet. After weaning from cardiopulmonary bypass, echocardiographic, hemodynamic, and sonomicrometry data were acquired at baseline and during 5 progressive TARs achieved with suture cinching. TA area and RV free wall strains and function were calculated from crystal coordinates.ResultsAfter pacing, changes in left ventricular (LV) ejection fraction and RV fractional area decreased significantly. Mean TA diameter increased from 25.1 ± 2.9 mm to 31.5 ± 3.3 mm (P = .005), and median TR (range, 0-3+) increased from 0 (0) to 3 (2) (P = .004). Progressive suture cinching reduced the TA area by 18 ± 6%, 38 ± 11%, 56 ± 10%, 67 ± 9%, and 76 ± 8%. Only aggressive annular reductions (67% and 76%) decreased TR significantly, but these were associated with deterioration of RV function and strain. A moderate annular reduction of 56% led to a substantial reduction of TR with little deleterious effect on regional RV function.ConclusionsA moderate TAR of approximately 50% may be most advantageous for correction of functional TR and simultaneous maintenance of regional RV performance. Additional subvalvular interventions may be needed to achieve complete valvular competence. 相似文献
143.
144.
145.
146.
147.
148.
Diane Santa Maria Charlene A. Flash Sarah Narendorf Anamika Barman-Adhikari Robin Petering Hsun-Ta Hsu Jama Shelton Kimberly Bender Kristin Ferguson 《The Journal of adolescent health》2019,64(5):574-580
Purpose
Evidence suggests that young adults experiencing homelessness (YEH) are at elevated risk of HIV compared to housed youth. Given the limited research on pre-exposure prophylaxis (PrEP) awareness among YEH, this study examined their PrEP knowledge and attitudes.Methods
Data from a cross-sectional survey among YEH (ages 18–26) (n?=?1,427) in seven U.S. cities were used to assess their knowledge and attitudes regarding PrEP to inform HIV prevention efforts.Results
Participants were primarily male youth of color. The mean age was 20.9years. While 66% felt at risk for HIV, only 14% strongly agreed that they try to protect themselves from getting infected with HIV. Most (84%) were eligible for PrEP based on risk, yet only 29% had knowledge of PrEP. Despite this, 59% reported they were likely/extremely likely to take PrEP. Access to free PrEP (55%), HIV testing (72%), healthcare (68%), and one-on-one (62%), and text messaging support (57%) were rated as very/extremely important for PrEP uptake and adherence.Conclusions
The results of this study suggest missed opportunities to prevent new HIV infections among YEH. Efforts to increase PrEP uptake among this population should consider provider- and system-level interventions to increase PrEP awareness, decrease PrEP-associated healthcare costs, improve access to PrEP providers, and provide in-person and text messaging support. 相似文献149.
Testicular schistosomiasis caused by Schistosoma mansoni is very rare and more so when associated with primary infertility. A 40 years old man from the Jos Plateau, North Central Nigeria presented with primary infertility after ten years of marriage. Sperm count revealed oligospermia and he also complained of inability to sustain erection. Testicular biopsy revealed several ova of Schistosoma mansoni in the connective tissue of the testes. Cases of infertility in endemic areas especially when there is no supply of potable water should raise suspicion of schistosomiasis among other pathologies and possible hormonal disturbances when the testes are involved. 相似文献
150.