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   11636篇
  免费   785篇
  国内免费   42篇
耳鼻咽喉   77篇
儿科学   299篇
妇产科学   250篇
基础医学   1969篇
口腔科学   97篇
临床医学   1074篇
内科学   2615篇
皮肤病学   186篇
神经病学   1326篇
特种医学   306篇
外科学   1151篇
综合类   50篇
一般理论   1篇
预防医学   892篇
眼科学   215篇
药学   768篇
中国医学   20篇
肿瘤学   1167篇
  2024年   10篇
  2023年   100篇
  2022年   159篇
  2021年   331篇
  2020年   216篇
  2019年   312篇
  2018年   404篇
  2017年   248篇
  2016年   251篇
  2015年   316篇
  2014年   452篇
  2013年   583篇
  2012年   995篇
  2011年   977篇
  2010年   521篇
  2009年   551篇
  2008年   854篇
  2007年   874篇
  2006年   758篇
  2005年   760篇
  2004年   681篇
  2003年   666篇
  2002年   634篇
  2001年   68篇
  2000年   63篇
  1999年   69篇
  1998年   98篇
  1997年   95篇
  1996年   70篇
  1995年   53篇
  1994年   48篇
  1993年   42篇
  1992年   27篇
  1991年   18篇
  1990年   18篇
  1989年   14篇
  1988年   16篇
  1987年   7篇
  1986年   16篇
  1985年   8篇
  1984年   8篇
  1983年   5篇
  1982年   7篇
  1979年   5篇
  1978年   6篇
  1976年   5篇
  1973年   4篇
  1968年   3篇
  1966年   4篇
  1964年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
OBJECTIVE: To assess the effectiveness of generic anti-retroviral drugs in terms of survival and virological and immunological responses, as well as their tolerability and the emergence of viral resistance. METHODS: A total of 109 HIV-1-infected patients were enrolled in a prospective cohort study in Yaoundé, Cameroon. Available generic drugs were a fixed-dose combination (FDC) of zidovudine (ZDV) and lamivudine (3TC), an FDC of 3TC, stavudine (d4T) and nevirapine (NVP), and individual formulations of ZDV, 3TC and NVP. RESULTS: At baseline, the median CD4 cell count was 150/mm3 [interquartile range (IQR) 61-223] and median viral load was 5.4 log10 copies/ml (IQR 4.8-5.6); 78% of patients received ZDV/3TC/NVP and 22% received 3TC/d4T/NVP. Median follow-up was 16 months (IQR 11-23). The survival probability was high (0.92 at 12 months); plasma viral load declined by a median of 3.3 log10 copies/ml and 86.9% of the intention-to-treat population had viral load <400 copies/ml at 12 months; CD4 count had increased by a median of 106 cells/mm3 at 12 months; drug resistance rarely emerged (incidence rate 3.2 per 100 person-years); and the treatments were reasonably well-tolerated (incidence rate of severe adverse effects 7.8 per 100 person-years). CONCLUSION: Together with previous pharmacological and clinical studies, this prospective study suggests that these generic antiretroviral drugs can be used in developing countries.  相似文献   
992.

Objectives

The aims of this study in SLE population were (1) to describe ultrasonography (US) joint abnormalities, (2) to estimate the reliability of clinical swollen joint count (C-SJC) and SLEDAI (C-SLEDAI) versus US-SJC and US-SLEDAI scores, (3) to highlight specific patterns of lupus patients with Power Doppler (PD) abnormalities.

Method

For this cross-sectional multicenter study, 151 consecutive adult SLE patients were recruited. Evaluation included a clinical standardized joint assessment, B-mode and PD US of 40 joints and 26 tendons blinded for clinical examination. Reliability and agreement between clinical and B-mode US were calculated using the intraclass correlation coefficients (ICC [95% Confidence Interval]).

Results

We found a very high frequency of subclinical US abnormalities in asymptomatic patients: 85% of patients without joint symptoms had at least 1 US abnormality. Among them 46 patients (87%) had a history of joint involvement. The most frequent abnormalities were joint effusmaions (108 patients), synovial hypertrophy (SH, 109 patients) and synovitis (61 patients). Joint or tendon PD signal (grade > 1) was found in 44% of patients (67/151). Synovitis were mainly located especially on MCPs and wrists. Even if reliability between clinical and grey-scale US SJC assessments was poor, reliability between clinical and US SLEDAI was good. Comparison between SLE patients with and without PD signal did not show any specific SLE pattern.

Conclusion

US may be useful to assess joint involvement in SLE patients but did not significantly change SLEDAI score.  相似文献   
993.
994.
Hepatitis E virus (HEV) can lead to chronic infection in solid-organ transplant patients. Ribavirin is efficient for treatment of chronically infected patients. Recently, the1634R mutation in the HEV polymerase has been associated with treatment failure. However, it is unclear if this mutation can be used as a prognostic marker of treatment outcome. We studied the prevalence of the 1634R mutation in the HEV polymerase of patients starting ribavirin therapy, the influence of the 1634R variants on the viral response, the frequency of the 1634R mutation in patients whose treatment failed, and its impact on ribavirin retreatment. We analyzed pretreatment samples from 63 solid-organ transplant patients with chronic hepatitis E using deep sequencing; 42 patients had a sustained virologic response (SVR), and 21 were non-SVR patients. We detected the 1634R variant by deep sequencing in 36.5% (23/63) of the patients (proportions, 1.3 to 100%). The 1634R variant was detected in 31.0% (13/42) of baseline plasma samples from patients with SVR and in 47.6% (10/21) in the other patients (P = 0.2). The presence of this mutation did not influence the initial decrease in viral RNA. Lastly, a second prolonged ribavirin treatment led to SVR in 70% of the patients who initially did not have SVR, despite the presence of the 1634R variant. We conclude that the presence of the 1634R variant at ribavirin initiation does not lead to absolute ribavirin resistance. Although its proportion increased in patients whose treatment failed, the presence of the 1634R variant did not compromise the response to a second ribavirin treatment.  相似文献   
995.
The aim of this study was to determine aztreonam (ATM) membrane permeability using Calu-3 cells and its plasma and pulmonary epithelial lining fluid (ELF) pharmacokinetics in rats after intratracheal nebulization and intravenous administration (15 mg · kg−1). ATM exhibits low Calu-3 permeability (0.07 ± 0.02 × 10−6 cm · s−1), and a high area under the ELF/unbound plasma concentration time curve between 0 and infinity (AUCELF/AUCu,plasma) ratio of 1,069 was observed after nebulization in rats. These results confirm that ATM is a low-permeability molecule and a good candidate for nebulization.  相似文献   
996.
Background: Functional ankle instability is the result of sensorimotor or structural deficits. The commonly used kinesio tape (KT) is supposed to have a positive influence on sensorimotor functions. Methods: Eight women and two men (mean ± SD, age 24.4 ± 3.3 years) with functional ankle instability with recurrent ankle sprains ran downhill on a treadmill (3.3 m/s and a negative slope of 5°). The first trial was without KT, the second with KT on the peroneus longus (PL) muscle. Neuromuscular activity was measured using surface electromyography for 15 seconds. Sensation of giving way was assessed with a visual analog scale (VAS). Comparisons were made between measurements with and without KT using the Wilcoxon rank sum test. The level of significance was set at P ≤ 0.05. Results: None of the chosen parameters for preactivation, reflex activation, or total activation showed statistically significant differences between the two trials (P > 0.05). The mean values for the sensation of giving way were lower with KT (VAS, median 1.2, range 0–2.8) than without (VAS, median 1.8, range 0–3.9), but did not reach statistical significance (P = 0.102) or clinical relevance. Conclusion: KT in participants with functional ankle instability (FAI) seems to have no effect on the neuromuscular activity of PL and sensation of giving way during downhill running.  相似文献   
997.
Construct: The impact of using nonbinary checklists for scoring residents from different levels of training participating in objective structured clinical examination (OSCE) progress tests was explored. Background: OSCE progress tests typically employ similar rating instruments as traditional OSCEs. However, progress tests differ from other assessment modalities because learners from different stages of training participate in the same examination, which can pose challenges when deciding how to assign scores. In an attempt to better capture performance, nonbinary checklists were introduced in two OSCE progress tests. The purposes of this study were (a) to identify differences in the use of checklist options (e.g., done satisfactorily, attempted, or not done) by task type, (b) to analyze the impact of different scoring methods using nonbinary checklists for two OSCE progress tests (nonprocedural and procedural) for Internal Medicine residents, and (c) to determine which scoring method is better suited for a given task. Approach: A retrospective analysis examined differences in scores (n = 119) for two OSCE progress tests (procedural and nonprocedural). Scoring methods (hawk, dove, and hybrid) varied in stringency in how they awarded marks for nonbinary checklist items that were rated as done satisfactorily, attempted, or not done. Difficulty, reliability (internal consistency), item-total correlations and pass rates were compared for each OSCE using the three scoring methods. Results: Mean OSCE scores were highest using the dove method and lowest using the hawk method. The hawk method resulted in higher item-total correlations for most stations, but there were differences by task type. Overall score reliability calculated using the three methods did not differ significantly. Pass–fail status differed as a function of scoring methods and exam type, with the hawk and hybrid methods resulting in higher failure rates for the nonprocedural OSCE and the dove method resulting in a higher failure rate for the procedural OSCE. Conclusion: The use of different scoring methods for nonbinary OSCE checklists resulted in differences in mean scores and pass–fail status. The results varied with procedural and nonprocedural OSCEs.  相似文献   
998.
OBJECTIVE: The aim of this study was to evaluate a speech synthesizer with respect to patterns of use and satisfaction, during a 2-month trial at home, and the usefulness of the word prediction function. DESIGN: Prospective study. PARTICIPANTS: Of the 24 patients with severe dysarthria recruited, 10 completed the study. Five patients had cerebral palsy, 3 amyotrophic lateral sclerosis, one locked-in syndrome, and one anoxic brain damage. Mean age was 32 (standard deviation 21) years (range 9-66 years). METHODS: Each participant received 10 hours of training with the device (Dialo) and then used it at home for 2 months. The main outcome measures were: level of use recorded by the device, Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) satisfaction score (maximum = 5), and time needed to take dictations of standard-dictionary and personal-dictionary words with and without word prediction. RESULTS: Level of use varied widely across participants. Overall satisfaction at the end of the home trial was high, with a mean QUEST score of 3.4 (SD 1) and was related to the level of use of the device. Level of satisfaction at the end of the training session could not predict the level of use at home. No significant differences were found in dictation-taking times with and without word prediction. However, 6 of the 10 patients took dictation faster with than without word prediction. CONCLUSION: This study provides the first evidence supporting the benefits of a speech synthesizer used at home for several weeks. Word prediction is useful for some patients even if increase in dictation speed did not reach significance.  相似文献   
999.
Psychological skills training (PST) is the systematic acquisition and practice of different psychological techniques to improve cognitive and technical performance. This training consists of three phases: education, skills acquisition and practice. Some of the psychological skills developed in this training include relaxation techniques, focusing and concentration skills, positive ‘self‐suggestion’ and visualisation exercises. Since the middle of the 20th century, PST has been successfully applied by athletes, performing artists, business executives, military personnel and other professionals in high‐risk occupations. Research in these areas has demonstrated the breadth and depth of the training's effectiveness. Despite the benefits realised in other professions, medicine has only recently begun to explore certain elements of PST. The present paper reviews the history and evidence behind the concept of PST. In addition, it presents some aspects of PST that have already been incorporated into medical training as well as implications for developing more comprehensive programmes to improve delivery of emergency medical care.  相似文献   
1000.
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