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   1695298篇
  免费   125667篇
  国内免费   3777篇
耳鼻咽喉   21753篇
儿科学   55699篇
妇产科学   46192篇
基础医学   241517篇
口腔科学   48801篇
临床医学   151560篇
内科学   333733篇
皮肤病学   38670篇
神经病学   131364篇
特种医学   63924篇
外国民族医学   242篇
外科学   257483篇
综合类   38987篇
现状与发展   4篇
一般理论   531篇
预防医学   124438篇
眼科学   40256篇
药学   123755篇
  7篇
中国医学   4476篇
肿瘤学   101350篇
  2021年   12807篇
  2019年   13546篇
  2018年   19984篇
  2017年   15231篇
  2016年   16629篇
  2015年   18990篇
  2014年   26251篇
  2013年   37989篇
  2012年   52795篇
  2011年   55515篇
  2010年   32815篇
  2009年   30729篇
  2008年   51583篇
  2007年   54877篇
  2006年   55346篇
  2005年   52635篇
  2004年   50811篇
  2003年   48223篇
  2002年   46444篇
  2001年   91835篇
  2000年   93658篇
  1999年   77010篇
  1998年   19744篇
  1997年   17292篇
  1996年   17409篇
  1995年   16768篇
  1994年   15305篇
  1993年   14092篇
  1992年   57404篇
  1991年   55311篇
  1990年   53005篇
  1989年   50792篇
  1988年   46177篇
  1987年   44963篇
  1986年   42253篇
  1985年   40012篇
  1984年   29376篇
  1983年   24934篇
  1982年   13922篇
  1979年   25566篇
  1978年   17608篇
  1977年   14932篇
  1976年   13902篇
  1975年   14581篇
  1974年   17660篇
  1973年   16959篇
  1972年   15686篇
  1971年   14467篇
  1970年   13445篇
  1969年   12533篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
151.
152.
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.  相似文献   
153.
154.
155.
156.
Abstract

This study is a single-center, retrospective analysis of postmenopausal women presenting with dyspareunia and vulvar pain, aiming to evaluate relative effectiveness of vestibular CO2 laser therapy as a treatment. Three monthly sessions of laser were performed to each patient and thereafter a three-months follow-up was stablished. A total number of 72 patients undergoing vestibular laser treatment were recruited from patient files in the period between 2016 and 2018. Among these, 39 women also received a concomitant treatment with ospemifene (60?mg/day) during the study period. There was a statistically significant reduction of all the symptoms in both groups up to the three month follow-up. Regarding dryness and dyspareunia, the relief tent to be more prominent in the ospemifene?+?laser group at all follow-ups and remained statistically significant at three-month follow-up. Specifically, vestibular dryness was significantly lower in the ospemifene?+?laser group compared with the laser treatment group (?87% vs???34%, respectively), and the vestibular health score started declining faster in the ospemifene?+?laser group. Although, additional research is needed to understand the mechanism of action, our data shows that a combination regimen of laser and ospemifene may improve clinical effectiveness for long-term treatment of symptoms associated with the under-recognized genitourinary syndrome of menopause.  相似文献   
157.
158.
Platelet α-granules release growth factors (GFs) that promote healing and tissue regeneration. Platelet-rich plasma (PRP) is shown to be beneficial in treating alopecia, and however, clinical response can be inconsistent. Due to several fold enrichment of platelets secreting large quantities of GFs following PRP injections, heterogeneity in amounts of GFs secreted by platelets may contribute to inconsistent clinical responses. Herein, we evaluated factors that could potentially contribute to heterogeneous secretion of GFs by platelets. We measured platelet secretion of transforming growth factor beta1 (TGFβ1), platelet-derived growth factor (PDGF-BB), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF2) in aliquots of de-identified PRP samples from female patients undergoing therapy in the hair disease clinic. Although secretion of GFs by platelets was comparable in PRP samples of patients with non-cicatricial and cicatricial alopecia, a Shapiro-Wilk test for normal distribution indicated significant variability across all patient samples. The amount of GF secreted by platelets was comparable when PRP prepared from two FDA-cleared devices with distinct techniques were compared. We provide evidence of platelets secreting heterogeneous amounts of GFs within each sample as high and low secretion of random factors could be simultaneously detected. These results suggest inherent heterogeneity in secretion of GFs by platelets in patient samples that are not influenced by the device used to prepare PRP. Since some GFs could have antagonistic effects on hair growth, a balance between amounts of growth promoting and inhibiting factors may be crucial in determining clinical response to PRP therapy.  相似文献   
159.
160.
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