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   867篇
  免费   43篇
  国内免费   92篇
耳鼻咽喉   7篇
儿科学   15篇
妇产科学   1篇
基础医学   119篇
口腔科学   9篇
临床医学   93篇
内科学   184篇
皮肤病学   15篇
神经病学   34篇
特种医学   27篇
外科学   46篇
综合类   18篇
预防医学   49篇
眼科学   3篇
药学   91篇
中国医学   2篇
肿瘤学   289篇
  2023年   2篇
  2022年   6篇
  2021年   16篇
  2020年   17篇
  2019年   19篇
  2018年   17篇
  2017年   14篇
  2016年   10篇
  2015年   17篇
  2014年   29篇
  2013年   41篇
  2012年   48篇
  2011年   48篇
  2010年   42篇
  2009年   29篇
  2008年   44篇
  2007年   107篇
  2006年   63篇
  2005年   48篇
  2004年   30篇
  2003年   22篇
  2002年   24篇
  2001年   32篇
  2000年   34篇
  1999年   28篇
  1998年   29篇
  1997年   17篇
  1996年   14篇
  1995年   20篇
  1994年   26篇
  1993年   16篇
  1992年   17篇
  1991年   13篇
  1990年   16篇
  1989年   14篇
  1988年   10篇
  1987年   4篇
  1986年   4篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1973年   1篇
  1972年   2篇
排序方式: 共有1002条查询结果,搜索用时 0 毫秒
91.
92.
93.
94.
Studies were carried out to determine the toxicity of some selected pesticides on fresh water fish in a tropical environment. The uptake of the pesticides lindane, pentachlorophenol (PCP), and propoxur, which are frequently used on farms, and in industries as well as by loggers and timber men on wood were studied in concrete ponds at the University of Cape Coast, in Ghana. The fish used for the study were Oreochromis niloticus, Clarias gariepinus, and Chrysicthys nigrodigitatus. They were obtained from cultured ponds in the Cape Coast and Mankessim districts in the Central Region and Weija Dam, in the Greater Accra region of Ghana. Single high lethal concentration (SD) or acute treatment and cumulative/chronic (or multiple minor) lethal concentration (CD) treatment were employed in administering the pesticides to the fish via water. Gas chromatograph electron capture detector analysis was done on the dead fish to see the extent of ingestion. The LC50 values obtained for lindane on the three fish samples were as follows: Chrysicthys – 0.38 mg L−1; Oreochromis – 0.42 mg L−1, and Clarias – 1.2 mg L−1. Mortalities occurred in fish within 3–5 days of application. For the PCP on Chrysicthys, Oreochromis, and Clarias species the LC50 values were 0.42, 0.32 and 0.64 mg L−1, respectively, for over a 2- to 3-day period. For a three-time influx period of propoxur the LC50 for Chrysicthys, Oreochromis, and Clarias, were 22.0, 30.40, and 45.04 (all in mg L−1), respectively. The results obtained indicated that the pesticides had adverse effects on the general growth and reproduction of fish as shown by gonadosomatic indices.  相似文献   
95.
96.
BackgroundCixutumumab (IMC-A12), a fully human immunoglobulin G1 (IgG1) monoclonal antibody, exerts preclinical activity in several sarcoma models and may be effective for the treatment of these tumours.MethodsIn this open-label, multicentre, phase 2 study, patients with previously treated advanced or metastatic rhabdomyosarcoma, leiomyosarcoma, adipocytic sarcoma, synovial sarcoma or Ewing family of tumours received intravenous cixutumumab (10 mg/kg) for 1 h every other week until disease progression or discontinuation. The primary end-point was the progression-free survival rate (PFR), defined as stable disease or better at 12 weeks. In each tier of disease histology, Simon’s optimum 2-stage design was applied (PFR at 12 weeks P0 = 20%, P1 = 40%, α = 0.10, β = 0.10). Stage 1 enrolled 17 patients in each disease group/tier, with at least four patients with stable disease or better required at 12 weeks to proceed to stage 2.ResultsA total of 113 patients were enrolled; all tiers except adipocytic sarcoma were closed after stage 1 due to futility. The 12-week PFR was 12% for rhabdomyosarcoma (n = 17), 14% for leiomyosarcoma (n = 22), 32% for adipocytic sarcoma (n = 37), 18% for synovial sarcoma (n = 17) and 11% for Ewing family of tumours (n = 18). Median progression-free survival (weeks) was 6.1 for rhabdomyosarcoma, 6.0 for leiomyosarcoma, 12.1 for adipocytic sarcoma, 6.4 for synovial sarcoma and 6.4 for Ewing family of tumours. Among all patients, the most frequent treatment-emergent adverse events (AEs) were nausea (26%), fatigue (23%), diarrhoea (23%) and hyperglycaemia (20%).ConclusionsPatients with adipocytic sarcoma may benefit from treatment with cixutumumab. Cixutumumab treatment was well tolerated, with limited gastrointestinal AEs, fatigue and hyperglycaemia.  相似文献   
97.
98.
99.
As a part of a survey to study the health and living conditions of the elderly population, a random sample of residents aged 65 and over are examined using the Clinical Interview Schedule (CIS) in order to evaluate their psychiatric status. The aim of this study is to evaluate this standard method of assessment as a case-identification instrument in our country. The schedule was completed by 91 subjects. It is easily administered, easily scored, and economical on time. Its completion rate is high. The weighted total scores (WTS) range from 0 to 48. Using the case criteria defined by Cooper & Schwarz (1982), 27 subjects (30%) are considered cases and 64 (70%) are regarded as non-cases. The sensitivity coefficients for the WTS are examined against the overall severity rating at different cut-off points. The optimum cut-off can be anywhere between 16 and 20 points. The WTS has higher validity coefficients to detect the following diagnostic categories (sensitivity, specificity): normals (100%,-); personality (100%, 92%) and affective disorders (100%, 75%). In general the CIS items are given low ratings. Psychotic symptoms are rarely found in this sample. One main problem arose: the item depersonalization is misunderstood by some patients probably because of interpreting it as an upsetting memory disturbance.  相似文献   
100.
Recommendations to adopt the supine position were followed by a dramatic decrease of SIDS. But no explanation has been given for the association between SIDS and the prone position nor for its decrease in the supine position. We report data on an infant and a mannequin demonstrating an increase in temperature around the head in the prone position. A 4-month-old boy presented an acute life-threatening event related to temperature after febrile otitis despite treatment: 40.5°C, heart rate 280 bpm with circulatory failure and cardiorespiratory arrest requiring resuscitation. There were no seizures. Blood and CSF cultures were negative. The course under antibiotics was favourable. On d 3, we measured temperature at several sites on and around the heat. Temperatures were higher in the prone than in the supine position in pericephalic areas: + 1°C (supracephalic), +2.5°C (peritemporal), and +3.5°C (submandibular). In a thermoregulated room, we used a mechanically ventilated mannequin of an infant. The prone position was also associated with an increase in temperature around the head: +3.3°C (supracephalic), +1.8°C (peritemporal), and +1.1°C (submandibular). Changing from the supine to prone position thus increased temperature around the head (infant and mannequin). To our knowledge, this has not been reported before. SIDS is related to factors modifying temperature status and environment. Furthermore, evacuation of heat is mandatory for an infant. We think the increase in temperature around the head in the prone position is due to the absence of convective fluxes, and speculate it could impair thermolysis.  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