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   3079429篇
  免费   220758篇
  国内免费   4424篇
耳鼻咽喉   43244篇
儿科学   100239篇
妇产科学   83144篇
基础医学   449993篇
口腔科学   85748篇
临床医学   277826篇
内科学   589510篇
皮肤病学   68699篇
神经病学   240485篇
特种医学   117271篇
外国民族医学   677篇
外科学   464090篇
综合类   63091篇
现状与发展   13篇
一般理论   1047篇
预防医学   234828篇
眼科学   72118篇
药学   235358篇
  16篇
中国医学   6540篇
肿瘤学   170674篇
  2021年   24007篇
  2019年   24456篇
  2018年   34084篇
  2017年   25966篇
  2016年   29237篇
  2015年   32855篇
  2014年   46067篇
  2013年   68965篇
  2012年   94726篇
  2011年   100811篇
  2010年   59896篇
  2009年   56345篇
  2008年   94386篇
  2007年   100797篇
  2006年   101696篇
  2005年   98351篇
  2004年   94163篇
  2003年   90826篇
  2002年   87867篇
  2001年   145913篇
  2000年   150087篇
  1999年   125954篇
  1998年   35445篇
  1997年   31150篇
  1996年   31458篇
  1995年   29582篇
  1994年   27218篇
  1993年   25665篇
  1992年   96980篇
  1991年   94308篇
  1990年   92444篇
  1989年   88951篇
  1988年   81539篇
  1987年   79940篇
  1986年   75049篇
  1985年   71540篇
  1984年   52948篇
  1983年   44984篇
  1982年   26248篇
  1979年   48330篇
  1978年   33974篇
  1977年   28849篇
  1976年   26906篇
  1975年   29449篇
  1974年   34963篇
  1973年   33470篇
  1972年   31671篇
  1971年   29920篇
  1970年   27566篇
  1969年   26376篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
Abstract

Objective: This study aims at identifying associations between cognitive function and suicidal ideation in the sample of patients with anxiety and mood disorders (AMD).

Methods: In sum, 186 (age = 39?±?12.3 years; 142 [76.3%] females) patients with AMD were enrolled in the study. Assessment included evaluation of socio-demographic information, medication use, anxiety and depression symptoms. Cognitive tests included measures of psychomotor performance and incidental learning using the Digit Symbol Test. Trail Making Tests respectively measured perceptual speed, task-switching and executive control. Additionally, 21 patients completed tests from the Cambridge Automated Neuropsychological Test Battery measuring set shifting (Interdimensional/extradimensional set-shift), executive planning (Stockings of Cambridge), and decision making (Cambridge Gamble Task [CGT]).

Results: Almost half (45.0%, n?=?86) of the study sample patients had experienced suicidal ideations. In multivariable regression analysis, suicidal ideation was associated with a greater overall proportion of bet and risk taking on the CGT task (β?=?0.726, p?=?.010 and β?=?0.634, p?=?.019), when controlling for socio-demographic characteristics, medication use, anxiety and depression symptoms.

Conclusions: Outpatients with AMD and suicidal ideation could be distinguished by the presence of cognitive deficits in the executive function domain, particularly in impulse-control and risk taking.  相似文献   
56.
57.
58.
The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (Leq) measurements were collected during flight operations (Leq (flt ops)), non-flight operations (Leq (non-flt ops)), and over 24-hr periods (Leq (24-hr)). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Value (TLV®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The Leq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between Leq (flt ops), Leq (non-flt ops), and Leq (24-hr) and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) Leq (24-hr): 70.8–105.4 dBA; (2) Leq (flt ops): 70–101.2 dBA; and (3) Leq (non-flt ops): 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean Leqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The Leqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.  相似文献   
59.
60.
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