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   1264907篇
  免费   73860篇
  国内免费   1444篇
耳鼻咽喉   16379篇
儿科学   41843篇
妇产科学   31960篇
基础医学   172018篇
口腔科学   31632篇
临床医学   108385篇
内科学   237645篇
皮肤病学   25583篇
神经病学   98420篇
特种医学   51958篇
外国民族医学   201篇
外科学   193814篇
综合类   24870篇
现状与发展   1篇
一般理论   276篇
预防医学   92984篇
眼科学   28383篇
药学   97338篇
  7篇
中国医学   3595篇
肿瘤学   82919篇
  2021年   8512篇
  2019年   8441篇
  2018年   32715篇
  2017年   25690篇
  2016年   29198篇
  2015年   12860篇
  2014年   17003篇
  2013年   24202篇
  2012年   38827篇
  2011年   53850篇
  2010年   37545篇
  2009年   29536篇
  2008年   49580篇
  2007年   53761篇
  2006年   34448篇
  2005年   33994篇
  2004年   33921篇
  2003年   33503篇
  2002年   30549篇
  2001年   60746篇
  2000年   62361篇
  1999年   51502篇
  1998年   12820篇
  1997年   11299篇
  1996年   11216篇
  1995年   10547篇
  1994年   9544篇
  1993年   9008篇
  1992年   38095篇
  1991年   36576篇
  1990年   36116篇
  1989年   34569篇
  1988年   31118篇
  1987年   30212篇
  1986年   28430篇
  1985年   26667篇
  1984年   19361篇
  1983年   16272篇
  1982年   8941篇
  1979年   17184篇
  1978年   11514篇
  1977年   10346篇
  1976年   8930篇
  1975年   10186篇
  1974年   11788篇
  1973年   11394篇
  1972年   10887篇
  1971年   10197篇
  1970年   9353篇
  1969年   9036篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Pulse oximetry is used widely to titrate oxygen therapy and for triage in patients who are critically ill. However, there are concerns regarding the accuracy of pulse oximetry in patients with COVID-19 pneumonitis and in patients who have a greater degree of skin pigmentation. We aimed to determine the impact of patient ethnicity on the accuracy of peripheral pulse oximetry in patients who were critically ill with COVID-19 pneumonitis by conducting a retrospective observational study comparing paired measurements of arterial oxygen saturation measured by co-oximetry on arterial blood gas analysis (SaO2) and the corresponding peripheral oxygenation saturation measured by pulse oximetry (SpO2). Bias was calculated as the mean difference between SaO2 and SpO2 measurements and limits of agreement were calculated as bias ±1.96 SD. Data from 194 patients (135 White ethnic origin, 34 Asian ethnic origin, 19 Black ethnic origin and 6 other ethnic origin) were analysed consisting of 6216 paired SaO2 and SpO2 measurements. Bias (limits of agreement) between SaO2 and SpO2 measurements was 0.05% (−2.21–2.30). Patient ethnicity did not alter this to a clinically significant degree: 0.28% (1.79–2.35), −0.33% (−2.47–2.35) and −0.75% (−3.47–1.97) for patients of White, Asian and Black ethnic origin, respectively. In patients with COVID-19 pneumonitis, SpO2 measurements showed a level of agreement with SaO2 values that was in line with previous work, and this was not affected by patient ethnicity.  相似文献   
82.
83.
84.
The Impella 5.0, a percutaneously inserted left ventricular assist device, has been used to support patients who have severe heart failure or who are undergoing high-risk percutaneous coronary intervention. We report our surgical placement of the Impella 5.0, through a graft sewn to the aorta, to unload the left ventricle of a 59-year-old man who was undergoing venoarterial extracorporeal membrane oxygenation for postcardiotomy shock. The patient underwent successful placement of a long-term left ventricular assist device before his discharge from the hospital. The versatility of the Impella 5.0 is exemplified in this patient who was successfully bridged to long-term support.  相似文献   
85.
86.
87.
88.
89.
90.
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   
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