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   710081篇
  免费   49023篇
  国内免费   1319篇
耳鼻咽喉   9187篇
儿科学   23433篇
妇产科学   17699篇
基础医学   110828篇
口腔科学   20069篇
临床医学   64060篇
内科学   135781篇
皮肤病学   16217篇
神经病学   49785篇
特种医学   25814篇
外国民族医学   76篇
外科学   104953篇
综合类   14834篇
现状与发展   2篇
一般理论   161篇
预防医学   51552篇
眼科学   16342篇
药学   54265篇
  3篇
中国医学   2366篇
肿瘤学   42996篇
  2021年   5525篇
  2018年   7964篇
  2017年   6188篇
  2016年   6907篇
  2015年   7620篇
  2014年   10390篇
  2013年   15556篇
  2012年   20715篇
  2011年   21705篇
  2010年   12838篇
  2009年   12045篇
  2008年   20170篇
  2007年   21734篇
  2006年   22116篇
  2005年   20652篇
  2004年   20171篇
  2003年   19113篇
  2002年   18625篇
  2001年   36468篇
  2000年   37037篇
  1999年   30513篇
  1998年   7914篇
  1997年   6706篇
  1996年   7005篇
  1995年   6663篇
  1994年   6127篇
  1993年   5615篇
  1992年   23057篇
  1991年   22979篇
  1990年   22374篇
  1989年   22132篇
  1988年   20086篇
  1987年   19476篇
  1986年   18514篇
  1985年   17353篇
  1984年   12737篇
  1983年   10785篇
  1982年   5939篇
  1979年   11543篇
  1978年   8147篇
  1977年   6844篇
  1976年   6610篇
  1975年   7288篇
  1974年   8523篇
  1973年   8154篇
  1972年   7673篇
  1971年   7143篇
  1970年   6897篇
  1969年   6315篇
  1968年   5795篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
IntroductionHip displacement is common in cerebral palsy (CP) and is related to the severity of neurological and functional impairment. It is a silent, but progressive disease, and can result in significant morbidity and decreased quality of life, if left untreated. The pathophysiology of hip displacement in CP is a combination of hip flexor-adductor muscle spasticity, abductor muscle weakness, and delayed weight-bearing, resulting in proximal femoral deformities and progressive acetabular dysplasia. Due to a lack of symptoms in the early stages of hip displacement, the diagnosis is easily missed. Awareness of this condition and regular surveillance by clinical examination and serial radiographs of the hips are the key to early diagnosis and treatment.Hip surveillance programmesSeveral population-based studies from around the world have demonstrated that universal hip surveillance in children with CP allows early detection of hip displacement and appropriate early intervention, with a resultant decrease in painful dislocations. Global hip surveillance models are based upon the patients’ age, functional level determined by the Gross Motor Function Classification system (GMFCS), gait classification, standardized clinical exam, and radiographic indices such as the migration percentage (MP), as critical indicators of progressive hip displacement.ConclusionDespite 25 years of evidence showing the efficacy of established hip surveillance programmes, there is poor awareness among healthcare professionals in India about the importance of regular hip surveillance in children with CP. There is a need for professional organizations to develop evidence-based guidelines for hip surveillance which are relevant to the Indian context.  相似文献   
3.
4.
5.
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   
6.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
7.
Bulletin of Experimental Biology and Medicine - Ammonium, an end-product of catabolism, in low doses can promote adaptation of metabolic pathways in erythrocytes under conditions of extreme...  相似文献   
8.
9.
We report two British cases of liver abscess, due to Klebsiella pneumoniae and associated with synchronous infection elsewhere, which required liver resection for definitive treatment. They illustrate the geographic spread of aggressive K pneumoniae liver infection and demonstrate the importance of early aggressive treatment.  相似文献   
10.
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