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   8430篇
  免费   470篇
  国内免费   58篇
耳鼻咽喉   125篇
儿科学   281篇
妇产科学   102篇
基础医学   1145篇
口腔科学   823篇
临床医学   625篇
内科学   1999篇
皮肤病学   137篇
神经病学   536篇
特种医学   351篇
外国民族医学   2篇
外科学   747篇
综合类   62篇
一般理论   3篇
预防医学   853篇
眼科学   128篇
药学   584篇
中国医学   43篇
肿瘤学   412篇
  2023年   71篇
  2022年   183篇
  2021年   271篇
  2020年   172篇
  2019年   228篇
  2018年   284篇
  2017年   199篇
  2016年   239篇
  2015年   275篇
  2014年   341篇
  2013年   433篇
  2012年   663篇
  2011年   648篇
  2010年   398篇
  2009年   332篇
  2008年   479篇
  2007年   487篇
  2006年   420篇
  2005年   373篇
  2004年   301篇
  2003年   245篇
  2002年   234篇
  2001年   142篇
  2000年   159篇
  1999年   150篇
  1998年   93篇
  1997年   89篇
  1996年   77篇
  1995年   49篇
  1994年   62篇
  1993年   50篇
  1992年   73篇
  1991年   65篇
  1990年   54篇
  1989年   70篇
  1988年   86篇
  1987年   51篇
  1986年   49篇
  1985年   72篇
  1984年   39篇
  1983年   23篇
  1982年   17篇
  1981年   23篇
  1980年   24篇
  1979年   15篇
  1978年   18篇
  1977年   16篇
  1976年   24篇
  1975年   19篇
  1968年   12篇
排序方式: 共有8958条查询结果,搜索用时 15 毫秒
91.
BackgroundThe primary role of infections in chronic urticaria (CU) is controversial. We hypothesised that streptococcal tonsillitis (ST) could be a primary cause of CU or acute recurrent urticaria (ARU).MethodsRetrospective study of 14 outpatients observed between January 2000 and December 2009, with CU/ARU and clinical and/or laboratorial suspicion of an aetiopathogenic link with ST. Clinical history, objective examination and laboratorial study were looked for. Three groups were defined: spontaneous resolution of urticaria, resolution after tonsillectomy, and still symptomatic.ResultsIn these patients, a causal relationship between ST and urticaria is supported by: markers of streptococcal infection, the perception of a clinical relationship between tonsillitis and urticaria, the decrease of urticaria severity with early antibiotherapy to tonsillitis and urticaria resolution after tonsillectomy.ConclusionsOur study encourages the investigation of tonsillitis in these otherwise idiopathic patients, especially until young adulthood and even in the absence of any symptoms.  相似文献   
92.
93.
BackgroundUsual treatment regimens with vancomycin often fail to provide adequate serum levels in patients with severe infections.MethodsRetrospective analysis of vancomycin trough serum measurements. The following parameters were calculated by Bayesian analysis: vancomycin clearance, distribution volume, and peak estimated concentrations. The area under the concentration curve (AUC) (total daily dose/24 h clearance of vancomycin) was used to determine the effectiveness of treatment through the ratio of AUC/minimum inhibitory concentration (MIC) above 400, using MIC = 1 μg/mL, based on isolates of Staphylococci in cultures.ResultsSixty-one vancomycin trough measurements were analyzed in 31 patients. AUC/MIC > 400 was obtained in 34 out of 61 dosages (55.7%), but the mean vancomycin dose required to achieve these levels was 81 mg/kg/day. In cases where the usual doses were administered (40–60 mg/kg/day), AUC/MIC > 400 was obtained in nine out of 18 dosages (50%), in 13 patients. Trough serum concentrations above 15 mg/L presented a positive predictive value of 100% and a negative predictive value of 71% for AUC/MIC > 400.ConclusionHigher than usual vancomycin doses may be required to treat staphylococcal infections in children with oncologic/hematologic diseases. Since the best known predictor of efficacy is the AUC/MIC ratio, serum trough concentrations must be analyzed in conjunction with MICs of prevalent Staphylococci and pharmacokinetic tools such as Bayesian analysis.  相似文献   
94.
95.
ObjectiveTo examine the influence of a preventative training program (PTP) on sagittal plane kinematics during different landing tasks and vertical jump height (VJH) in males.DesignSix weeks prospective exercise intervention.ParticipantsFifteen male volleyball athletes (13 ± 0.7 years, 1.70 ± 0.12 m, 60 ± 12 kg).InterventionsPTP consisting of plyometric, balance and core stability exercises three times per week for six weeks. Bilateral vertical jumps with double leg (DL) and single leg (SL) landings were performed to measure the effects of training.Main outcome measurementsKinematics of the knee and hip before and after training and VJH attained during both tasks after training. The hypothesis was that the PTP would produce improvements in VJH, but would not generate great changes in biomechanical behavior.ResultsThe only change identified for the SL was the longest duration of landing, which represents the time spent from initial ground contact to maximum knee flexion, after training, while increased angular displacement of the knee was observed during DL. The training did not significantly alter the VJH in either the SL (difference: 2.7 cm) or the DL conditions (difference: 3.5 cm).ConclusionsDespite the PTP’s effectiveness in inducing some changes in kinematics, the changes were specific for each task, which highlights the importance of the specificity and individuality in selecting prevention injury exercises. Despite the absence of significant increases in the VJH, the absolute differences after training showed increases corroborating with the findings of statistically powerful studies that compared the results with control groups. The results suggest that short-term PTPs in low risk young male volleyball athletes may enhance performance and induce changes in some kinematic parameters.  相似文献   
96.
97.
Kinnison  ML; Powe  NR; Steinberg  EP 《Radiology》1989,170(2):381-389
The authors reviewed 100 randomized controlled trials (RCTs) conducted in humans to compare safety or efficacy of new low-osmolality contrast media (LOM) with that of high-osmolality contrast media (HOM). Findings of the 43 RCTs judged to be of the highest quality suggest that the efficacy of LOM in imaging is equal or superior to that of HOM for all routes of administration. Heat sensation occurred less often with LOM for all routes and pain occurred less often with LOM for intraarterial routes. No differences were seen in nephrotoxicity or in frequency of nausea, vomiting, urticaria, bronchospasm, laboratory test abnormalities, or neurologic events. Greater cardiovascular changes were seen with HOM, including increased or decreased heart rate, increased left ventricular end-diastolic pressure, decreased systolic pressure, and QT prolongation, depending on route of administration. To demonstrate whether a reduction in clinically significant adverse outcomes truly occurs with LOM, trials will need to enlist larger numbers of patients and employ appropriate outcome measures. Future trials should stratify patients according to their risk of adverse reactions to provide better information about benefits of LOM in low- versus high-risk patients.  相似文献   
98.
99.
100.
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