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   2272188篇
  免费   174503篇
  国内免费   4090篇
耳鼻咽喉   31754篇
儿科学   74993篇
妇产科学   64757篇
基础医学   322171篇
口腔科学   65757篇
临床医学   197687篇
内科学   445911篇
皮肤病学   48539篇
神经病学   183358篇
特种医学   91023篇
外国民族医学   767篇
外科学   348506篇
综合类   54455篇
现状与发展   3篇
一般理论   769篇
预防医学   173281篇
眼科学   52601篇
药学   168863篇
  3篇
中国医学   4290篇
肿瘤学   121293篇
  2018年   21566篇
  2016年   18706篇
  2015年   21546篇
  2014年   30036篇
  2013年   46166篇
  2012年   62224篇
  2011年   65762篇
  2010年   39106篇
  2009年   37448篇
  2008年   62974篇
  2007年   66631篇
  2006年   67513篇
  2005年   65727篇
  2004年   64377篇
  2003年   61711篇
  2002年   60595篇
  2001年   104172篇
  2000年   107757篇
  1999年   91570篇
  1998年   25228篇
  1997年   23054篇
  1996年   22874篇
  1995年   22047篇
  1994年   20760篇
  1993年   19683篇
  1992年   74855篇
  1991年   72481篇
  1990年   70862篇
  1989年   68635篇
  1988年   63772篇
  1987年   62889篇
  1986年   60080篇
  1985年   57743篇
  1984年   43359篇
  1983年   37109篇
  1982年   22000篇
  1981年   19517篇
  1980年   18447篇
  1979年   40884篇
  1978年   28536篇
  1977年   24013篇
  1976年   22671篇
  1975年   24312篇
  1974年   29551篇
  1973年   28409篇
  1972年   26280篇
  1971年   24616篇
  1970年   22960篇
  1969年   21533篇
  1968年   20010篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
93.
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   
94.
95.
96.
97.
ABSTRACT

Objectives: The present study investigated the relationships of enculturation and depressive symptoms with health risk behavior engagement in Mexican-American college students and examined how these relationships differed by gender. Previous research has noted consistent gender differences in health risk behavior (e.g. alcohol use, substance use, and risky sexual behavior) among Latina/os, and emphasized the role of U.S. acculturation in this difference. Research examining the role of heritage cultural retention (i.e. enculturation), and including the added influence of mental health variables, such as depressive symptoms, is currently lacking. This study sought to address this gap.

Design: A large sample (N?=?677) of Mexican-American college students from four universities (located in New York, California, Florida, and Texas) completed an online questionnaire assessing health risk behaviors and corresponding variables.

Results: We found that males who endorsed more behavioral enculturation and depressive symptoms were more likely to engage in health risk behavior than all others in the sample. Contrary to previous literature, no relationship was found between behavioral enculturation and health risk behavior in females.

Conclusion: The current study found behavioral enculturation to be associated with depressive symptoms, and in turn with health risk behaviors among the males in our sample. Additional research will be needed to identify the mechanism underlying the relationship between enculturation and depressive symptoms as well as between depressive symptoms and risky behavior.  相似文献   
98.
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   
99.
100.
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