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   233245篇
  免费   15371篇
  国内免费   980篇
耳鼻咽喉   2547篇
儿科学   5988篇
妇产科学   4418篇
基础医学   29115篇
口腔科学   4425篇
临床医学   23891篇
内科学   48762篇
皮肤病学   3223篇
神经病学   23577篇
特种医学   10144篇
外国民族医学   13篇
外科学   36997篇
综合类   2514篇
现状与发展   1篇
一般理论   177篇
预防医学   16283篇
眼科学   5630篇
药学   15439篇
  1篇
中国医学   318篇
肿瘤学   16133篇
  2023年   1234篇
  2022年   851篇
  2021年   5241篇
  2020年   3063篇
  2019年   5076篇
  2018年   6079篇
  2017年   4460篇
  2016年   4861篇
  2015年   5763篇
  2014年   8387篇
  2013年   11292篇
  2012年   17339篇
  2011年   18086篇
  2010年   10118篇
  2009年   9348篇
  2008年   15927篇
  2007年   16732篇
  2006年   16254篇
  2005年   16107篇
  2004年   15158篇
  2003年   13821篇
  2002年   13209篇
  2001年   1944篇
  2000年   1442篇
  1999年   2028篇
  1998年   2800篇
  1997年   2190篇
  1996年   1550篇
  1995年   1714篇
  1994年   1497篇
  1993年   1468篇
  1992年   948篇
  1991年   935篇
  1990年   783篇
  1989年   748篇
  1988年   683篇
  1987年   612篇
  1986年   629篇
  1985年   683篇
  1984年   896篇
  1983年   773篇
  1982年   1020篇
  1981年   943篇
  1980年   827篇
  1979年   449篇
  1978年   501篇
  1977年   435篇
  1976年   402篇
  1975年   304篇
  1974年   305篇
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
61.
62.
Adrenoceptor and calcium channel modulating medications are widely used in clinical practice for acute neurological and systemic conditions. It is generally assumed that the cerebrovascular effects of these drugs mirror that of their systemic effects – and this is reflected in how these medications are currently used in clinical practice. However, recent research suggests that there are distinct cerebrovascular-specific effects of these medications that are related to the unique characteristics of the cerebrovascular anatomy including the regional heterogeneity in density and distribution of adrenoceptor subtypes and calcium channels along the cerebrovasculature. In this review, we critically evaluate existing basic science and clinical research to discuss known and putative interactions between adrenoceptor and calcium channel modulating pharmacotherapies, the neurovascular unit, and cerebrovascular anatomy. In doing so, we provide a rationale for selecting vasoactive medications based on lesion location and lay a foundation for future investigations that will define neuroprotective paradigms of adrenoceptor and calcium channel modulating therapies to improve neurological outcomes in acute neurological and systemic disorders.  相似文献   
63.
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   
64.
65.
Abstract

Objective

Two similarly designed studies compared user experiences with a second-generation extra-thin-wall, 5-bevel 32?G?×?4?mm pen needle (PN) with redesigned hub versus four thinner commercially available PNs.  相似文献   
66.
67.
68.

Background

A history of childhood maltreatment and psychopathology are common in adults with obesity.

Objectives

To report childhood maltreatment and to evaluate associations between severity and type of childhood maltreatment and lifetime history of psychopathology among adults with severe obesity awaiting bariatric surgery.

Setting

Four clinical centers of the Longitudinal Assessment of Bariatric Surgery Research Consortium.

Methods

The Childhood Trauma Questionnaire, which assesses presence/severity (i.e., none, mild, moderate, severe) of physical abuse, mental abuse, physical neglect, mental neglect, and sexual abuse, was completed by 302 female and 66 male bariatric surgery patients. Presurgery lifetime history of psychopathology and suicidal ideation/behavior were assessed with the Structured Clinical Interview for DSM-IV and the Suicidal Behavioral Questionnaire-Revised, respectively. Presurgery lifetime history of antidepressant use was self-reported.

Results

Two thirds (66.6%) of females and 47.0% of males reported at least 1 form of childhood trauma; 42.4% and 24.2%, respectively, at greater than or equal to moderate severity. Among women, presence/greater severity of childhood mental or physical abuse or neglect was associated with a higher risk of history of psychopathology (i.e., major depressive disorder, posttraumatic stress disorder, other anxiety disorder, alcohol use disorder, binge eating disorder), suicidal ideation/behavior and antidepressant use (P for all ≤ .02). These associations were independent of age, race, education, body mass index, and childhood sexual abuse. Childhood sexual abuse was independently associated with a history of suicidal ideation/behavior and antidepressant use only (P for both ≤ .05). Statistical power was limited to evaluate these associations among men.

Conclusion

Among women with obesity, presence/severity of childhood trauma was positively associated with relatively common psychiatric disorders.  相似文献   
69.
70.
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