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   424454篇
  免费   19167篇
  国内免费   1408篇
耳鼻咽喉   5401篇
儿科学   13304篇
妇产科学   10237篇
基础医学   53892篇
口腔科学   10028篇
临床医学   38715篇
内科学   83551篇
皮肤病学   7681篇
神经病学   34894篇
特种医学   20375篇
外国民族医学   110篇
外科学   65563篇
综合类   3618篇
现状与发展   1篇
一般理论   180篇
预防医学   32447篇
眼科学   9734篇
药学   28652篇
  3篇
中国医学   459篇
肿瘤学   26184篇
  2022年   2261篇
  2021年   5417篇
  2020年   3181篇
  2019年   5129篇
  2018年   9338篇
  2017年   8124篇
  2016年   7853篇
  2015年   10299篇
  2014年   12366篇
  2013年   14372篇
  2012年   26536篇
  2011年   22363篇
  2010年   12081篇
  2009年   12918篇
  2008年   17732篇
  2007年   19203篇
  2006年   19039篇
  2005年   26604篇
  2004年   27136篇
  2003年   21583篇
  2002年   16436篇
  2001年   6252篇
  2000年   3136篇
  1999年   7848篇
  1998年   3296篇
  1997年   2480篇
  1996年   2287篇
  1995年   2143篇
  1992年   7851篇
  1991年   8026篇
  1990年   8134篇
  1989年   7689篇
  1988年   7159篇
  1987年   6848篇
  1986年   6590篇
  1985年   5927篇
  1984年   4497篇
  1983年   3704篇
  1979年   4292篇
  1978年   2880篇
  1977年   2240篇
  1975年   2797篇
  1974年   3424篇
  1973年   3011篇
  1972年   2934篇
  1971年   2907篇
  1970年   2669篇
  1969年   2553篇
  1968年   2319篇
  1967年   2241篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
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   
12.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
13.
This article describes a case of anaphylaxis secondary to chlorhexidine during urethral catheterisation. Despite little evidence for the use of antiseptic lubricants in preventing catheter-associated urinary tract infections, the distribution and use of such products continues to be widespread. Chlorhexidine-free lubricating gel is widely available and should be used for urological procedures wherever possible.  相似文献   
14.
15.
16.
17.
18.
European Journal of Orthopaedic Surgery & Traumatology - The goals of this study were to compare patient satisfaction and wound-related complications in patients receiving 2-octyl cyanoacrylate...  相似文献   
19.
20.
Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate the long-term safety and efficacy of intrastromal bevacizumab for treatment of deep corneal neovascularization in...  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