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   1162篇
  免费   76篇
  国内免费   1篇
耳鼻咽喉   3篇
儿科学   49篇
妇产科学   24篇
基础医学   134篇
口腔科学   19篇
临床医学   107篇
内科学   199篇
皮肤病学   28篇
神经病学   73篇
特种医学   83篇
外科学   272篇
综合类   18篇
预防医学   72篇
眼科学   14篇
药学   91篇
肿瘤学   53篇
  2022年   11篇
  2021年   31篇
  2020年   13篇
  2019年   30篇
  2018年   24篇
  2017年   16篇
  2016年   20篇
  2015年   15篇
  2014年   18篇
  2013年   34篇
  2012年   35篇
  2011年   46篇
  2010年   33篇
  2009年   36篇
  2008年   41篇
  2007年   41篇
  2006年   44篇
  2005年   31篇
  2004年   32篇
  2003年   28篇
  2002年   35篇
  2001年   35篇
  2000年   26篇
  1999年   36篇
  1998年   20篇
  1997年   22篇
  1996年   17篇
  1995年   13篇
  1993年   11篇
  1992年   30篇
  1991年   33篇
  1990年   29篇
  1989年   30篇
  1988年   24篇
  1987年   31篇
  1986年   13篇
  1985年   21篇
  1984年   13篇
  1983年   9篇
  1982年   11篇
  1981年   11篇
  1980年   16篇
  1979年   25篇
  1978年   10篇
  1977年   12篇
  1976年   10篇
  1974年   16篇
  1971年   10篇
  1968年   12篇
  1967年   11篇
排序方式: 共有1239条查询结果,搜索用时 15 毫秒
31.

Introduction and hypothesis

The goal of this study was to characterize associations between caffeine consumption and severity of urinary incontinence (UI) in US women. We hypothesized that moderate and high caffeine intake would be associated with UI in US women when controlling for other factors associated with UI.

Methods

US women participated in the 2005–2006 and 2007–2008 National Health and Nutrition Examination Survey (NHANES), a cross-sectional, nationally representative survey. Using the Incontinence Severity Index, UI was categorized as “any” and “moderate/severe”. Types of UI included stress, urge, mixed, and other. Food diaries were completed, and average water (grams/day), total dietary moisture (grams/day), and caffeine (milligrams/day) intake were calculated into quartiles. Stepwise logistic regression models were constructed adjusting for sociodemographics, chronic diseases, body mass index, self-rated health, depression, physical activity, alcohol use, dietary water and moisture intake, and reproductive factors.

Results

From the 4,309 nonpregnant women (aged ≥20 years) who had complete UI and dietary data, UI prevalence for any UI was 41.0 % and 16.5 % for moderate/severe UI, with stress UI the most common type (36.6 %). Women consumed a mean caffeine intake of 126.7 mg/day. After adjusting for multiple factors, caffeine intake in the highest quartile (≥204 mg/day) was associated with any UI [prevalence odds ratio (POR) 1.47, 95 % confidence interval (CI) 1.07–2.01], but not moderate/severe UI (POR 1.42, 95 % CI 0.98–2.07). Type of UI (stress, urgency, mixed) was not associated with caffeine intake.

Conclusions

Caffeine intake ≥204 mg/day was associated with any UI but not with moderate/severe UI in US women.  相似文献   
32.
We estimated the temporal course of posttraumatic stress disorder (PTSD) in Vietnam‐era veterans using a national sample of male twins with a 20‐year follow‐up. The complete sample included those twins with a PTSD diagnostic assessment in 1992 and who completed a DSM‐IV PTSD diagnostic assessment and a self‐report PTSD checklist in 2012 (n = 4,138). Using PTSD diagnostic data, we classified veterans into 5 mutually exclusive groups, including those who never had PTSD, and 4 PTSD trajectory groups: (a) early recovery, (b) late recovery, (c) late onset, and (d) chronic. The majority of veterans remained unaffected by PTSD throughout their lives (79.05% of those with theater service, 90.85% of those with nontheater service); however, an important minority (10.50% of theater veterans, 4.45% of nontheater veterans) in 2012 had current PTSD that was either late onset (6.55% theater, 3.29% nontheater) or chronic (3.95% theater, 1.16% nontheater). The distribution of trajectories was significantly different by theater service (p < .001). PTSD remains a prominent issue for many Vietnam‐era veterans, especially for those who served in Vietnam.  相似文献   
33.
34.
Within the spectrum of acute aortic syndromes, intramural hematoma (IMH) is a distinct lesion that is characterized by crescentic or circumferential thickening of the aortic wall in the absence of an intimal defect. The reported incidence of IMH among all type A acute aortic syndromes ranges from 3.5% to 28.3%. As compared with acute aortic dissection, IMH is a disease of the elderly, and it tends to have reduced rates of malperfusion syndromes, aortic insufficiency, and root dilation, yet also tends to have increased rates of pericardial effusion, cardiac tamponade, and periaortic hematoma. With respect to natural history, IMH may progress to classic dissection, frank rupture, or aneurysmal dilation; yet, IMH may also regress and be completely resorbed. However, studies disagree over the rates of progression or regression; as such, few studies agree on the short-term and long-term prognosis associated with IMH. American and European guidelines advocate emergent surgery for all acutely presenting type A IMH. At a minimum, supracoronary replacement of the aorta with hemiarch reconstruction is the preferred extent of operative repair to reduce rates of long-term reintervention for disease progression. However, valve and/or root procedures may be necessary proximally, while total arch reconstruction or hybrid procedures for the descending aorta may be necessary distally. Much remains unknown for IMH, including the ideal extent of aortic repair, risk-stratification for elderly patients, and the optimal treatment paradigm for stable, uncomplicated IMH. As such, IMH remains a diagnostic and therapeutic challenge for the cardiovascular surgeon.  相似文献   
35.
36.
37.
38.

Purpose

To assess the relationship of posttraumatic stress disorder (PTSD) with health functioning and disability in Vietnam-era Veterans.

Methods

A cross-sectional study of functioning and disability in male Vietnam-era Veteran twins. PTSD was measured by the Composite International Diagnostic Interview; health functioning and disability were assessed using the Veterans RAND 36-Item Health Survey (VR-36) and the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0). All data collection took place between 2010 and 2012.

Results

Average age of the 5,574 participating Veterans (2,102 Vietnam theater and 3,472 non-theater) was 61.0 years. Veterans with PTSD had poorer health functioning across all domains of VR-36 and increased disability for all subscales of WHODAS 2.0 (all p < .001) compared with Veterans without PTSD. Veterans with PTSD were in poorer overall health on the VR-36 physical composite summary (PCS) (effect size = 0.31 in theater and 0.47 in non-theater Veterans; p < .001 for both) and mental composite summary (MCS) (effect size = 0.99 in theater and 0.78 in non-theater Veterans; p < .001 for both) and had increased disability on the WHODAS 2.0 summary score (effect size = 1.02 in theater and 0.96 in non-theater Veterans; p < .001 for both). Combat exposure, independent of PTSD status, was associated with lower PCS and MCS scores and increased disability (all p < .05, for trend). Within-pair analyses in twins discordant for PTSD produced consistent findings.

Conclusions

Vietnam-era Veterans with PTSD have diminished functioning and increased disability. The poor functional status of aging combat-exposed Veterans is of particular concern.  相似文献   
39.
40.

Objectives

There are minimal data regarding clinical outcomes and echocardiographic findings after transcatheter mitral valve-in-valve replacement (TMVR) compared with redo surgical mitral valve replacement (SMVR).

Background

TMVR therapy has emerged as therapy for a degenerated bioprosthetic valve failure.

Methods

The authors retrospectively identified patients with degenerated mitral bioprostheses who underwent redo SMVR or TMVR at 3 U.S. institutions. The authors compared clinical and echocardiographic outcomes of patients who had TMVR with those of patients who underwent redo SMVR.

Results

Sixty-two patients underwent TMVR and 59 patients underwent SMVR during the study period. Mean age and the Society of Thoracic Surgeons Predicted Risk of Mortality (STS PROM) scores were significantly higher in patients with TMVR than in those with SMVR (age 74.9 ± 9.4 years vs. 63.7 ± 14.9 years; p < 0.001; STS PROM 12.7 ± 8.0% vs. 8.7 ± 10.1%; p < 0.0001). Total procedure time, intensive care unit hours, and post-procedure length of stay were all significantly shorter in the TMVR group. There was no difference in mortality at 1 year between the 2 groups (TMVR 11.3% vs. SMVR 11.9%; p = 0.92). Mean mitral valve pressure gradient and the grade of mitral regurgitation (MR) were similar between the TMVR group and the SMVR group (mitral valve pressure gradient 7.1 ± 2.5 mm Hg vs. 6.5 ± 2.5 mm Hg; p = 0.42; MR [≥moderate] 3.8% vs. 5.6%; p = 1.00) at 30 days. At 1 year, the mitral valve pressure gradient was higher in the TMVR group (TMVR 7.2 ± 2.7 vs. SMVR 5.5 ± 1.8; p = 0.01), although there was no difference in the grade of MR.

Conclusions

Despite the higher STS PROM in TMVR patients, there was no difference in 1-year mortality between the TMVR and SMVR groups. Echocardiographic findings after TMVR were similar to SMVR at 30 days. There was a statistically significant difference in mitral gradient at 1 year, though this is likely not clinically important. TMVR may be an alternative to SMVR in patients with previous mitral bioprosthetic valves.  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