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   1690625篇
  免费   126536篇
  国内免费   9531篇
耳鼻咽喉   23697篇
儿科学   52876篇
妇产科学   44550篇
基础医学   234112篇
口腔科学   45639篇
临床医学   149354篇
内科学   334016篇
皮肤病学   36316篇
神经病学   126813篇
特种医学   65849篇
外国民族医学   732篇
外科学   254954篇
综合类   54912篇
现状与发展   25篇
一般理论   425篇
预防医学   119378篇
眼科学   38228篇
药学   132535篇
  160篇
中国医学   11656篇
肿瘤学   100465篇
  2021年   14330篇
  2019年   13861篇
  2018年   19379篇
  2017年   15645篇
  2016年   16312篇
  2015年   19501篇
  2014年   26747篇
  2013年   37722篇
  2012年   51876篇
  2011年   54462篇
  2010年   34119篇
  2009年   31936篇
  2008年   50231篇
  2007年   53345篇
  2006年   52984篇
  2005年   50150篇
  2004年   47760篇
  2003年   46136篇
  2002年   44586篇
  2001年   89504篇
  2000年   92278篇
  1999年   77604篇
  1998年   20047篇
  1997年   17798篇
  1996年   17696篇
  1995年   16628篇
  1994年   15632篇
  1993年   14362篇
  1992年   58710篇
  1991年   56533篇
  1990年   54739篇
  1989年   52649篇
  1988年   48144篇
  1987年   47022篇
  1986年   43617篇
  1985年   41560篇
  1984年   30312篇
  1983年   25306篇
  1982年   14121篇
  1981年   12654篇
  1979年   26308篇
  1978年   17858篇
  1977年   15240篇
  1976年   13697篇
  1975年   15034篇
  1974年   17476篇
  1973年   16750篇
  1972年   15556篇
  1971年   14275篇
  1970年   13392篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Abstract

This study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos.  相似文献   
12.
13.
Parhiala  P.  Ranta  K.  Gergov  V.  Kontunen  J.  Law  R.  La Greca  A. M.  Torppa  M.  Marttunen  M. 《School mental health》2020,12(2):265-283

In order to offer early and accessible treatment for adolescents with depression, brief and effective treatments in adolescents’ everyday surroundings are needed. This randomized controlled trial studied the preliminary effectiveness, feasibility, and acceptability of interpersonal counseling (IPC) and brief psychosocial support (BPS) in school health and welfare services. The study was conducted in the 28 lower secondary schools of a large city in Southern Finland, randomized to provide either IPC or BPS. Help-seeking 12–16-year-old adolescents with mild-to-moderate depression, with and without comorbid anxiety, were included in the study. Fifty-five adolescents received either 6 weekly sessions of IPC or BPS and two follow-up sessions. Outcome measures included self- and clinician-rated measures of depression, global functioning, and psychological distress/well-being. To assess feasibility and acceptability of the treatments, adolescents’ and counselors’ treatment compliance and satisfaction with treatment were assessed. Both treatments were effective in reducing depressive disorders and improving adolescents’ overall functioning and well-being. At post-treatment, in both groups, over 50% of adolescents achieved recovery based on self-report and over 70% based on observer report. Effect sizes for change were medium or large in both groups at post-treatment and increased at 6-month follow-up. A trend indicating greater baseline symptom severity among adolescents treated in the IPC-providing schools was observed. Adolescents and counselors in both groups were satisfied with the treatment, and 89% of the adolescents completed the treatments and follow-ups. This trial suggests that both IPC and BPS are feasible, acceptable, and effective treatments for mild-to-moderate depression in the school setting. In addition, IPC seems effective even if comorbid anxiety exists. Our study shows that brief, structured interventions, such as IPC and BPS, are beneficial in treating mild-to-moderate depression in school settings and can be administered by professionals working at school.

Trial registrationhttp://www.clinicaltrials.gov. Unique identifier: NCT03001245.

  相似文献   
14.
ABSTRACT

Purpose

To investigate the effect of 1% tropicamide on anterior chamber aqueous flare (ACAF) measurements acquired with laser flare meter in patients with pseudoexfoliation.  相似文献   
15.

Background and aims

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

Methods and results

In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.

Conclusion

SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE.  相似文献   
16.
The Latin American population has a double way of immigration, one toward the United States by proximity and another toward Spain by sociocultural affinity. This population increase is affecting organ donation and transplantation in receiving countries.

Objective

To analyze the brain death (BD) concept knowledge in the Dominican Republic immigrant population in Florida (United States) and Spain.

Method

Population under study: Population born in the Dominican Republic, resident in Florida (United States) and in Spain. Inclusion criteria: Population older than 15 years stratified by age and sex. Assessment instrument: Donation attitude questionnaire PCID-DTO-Ríos. Fieldwork: Random selection based on stratification. Immigration support association collaboration in Florida and Spain was needed to locate potential respondents. Completion was anonymous and self-administered, with verbal consent.

Results

A total of 123 respondents, 57 residents in Spain and 66 in Florida, have been included in the study. The 27% (n = 33) of the respondents knowledgeable of the BD concept consider it the death of an individual. Of the remainder, 52% (n = 64) do not know about it, and the remaining 21% (n = 26) believe it does not mean the death of a patient. No differences were observed regarding migration countries (P > .05). There was no association of the BD concept with other psychosocial factors analyzed or with the attitude toward organ donation.

Conclusions

Knowledge of the BD concept among the Dominican immigrant population is similar in Spain and Florida, and, unlike most studies, there is no objective association with the attitude toward organ donation.  相似文献   
17.
Membrane trafficking processes are presumably vital for axonal regeneration after injury, but mechanistic understanding in this regard has been sparse. A recent loss-of-function screen had been carried out for factors important for axonal regeneration by cultured cortical neurons and the results suggested that the activity of a number of Rab GTPases might act to restrict axonal regeneration. A loss of Rab27b, in particular, is shown to enhance axonal regeneration in vitro, as well as in C. elegans and mouse central nervous system injury models in vivo. Possible mechanisms underlying this new finding, which has important academic and translational implication, are discussed.  相似文献   
18.
Abstract

Purpose: We examined underlying psychosocial processes of a behavioral treatment for urinary incontinence (UI) of prostate cancer survivors.

Design: Secondary analysis of data collected from a clinical trial.

Sample: Two hundred forty-four prostate cancer survivors who participated in a clinical trial of behavioral intervention to UI as intervention or control subjects.

Methods: The participants had a 3-month behavioral intervention or usual care and were followed up for an additional 3?months. They were assessed at baseline, 3, and 6?months. Latent growth curve models were performed to examine trajectories of each study variable and relationships among the variables.

Findings: Increasing self-efficacy and social support were significantly and independently associated with more reduction of urinary leakage frequency over time.

Implications for psychosocial oncology: Providing problem-solving skills and social support, including peer support, are essential for empowering patients to reduce UI.  相似文献   
19.
石颖  吴玲  李林苇 《中国临床康复》2006,10(48):151-153
目的:综述运动系统软组织损伤引起慢性疼痛的各种治疗方法的研究进展。资料来源:应用计算机检索Medline1980—01/2006—04与运动系统软组织损伤引起慢性疼痛的治疗相关文章,检索词“Soft tissue injury,pain.chronic,comprehensive therapy”,并限定文章语言种类为“English”;同时计算机检索中国期刊全文数据库1994—01/2006-04期间的相关文章,检索词“软组织损伤、慢性疼痛、治疗方法”,并限定语言种类为中文。同时手工查阅相关书籍。资料选择:对资料进行初审,所选文献内容符合:①软组织损伤引起的慢性疼痛药物治疗的研究。②软组织损伤引起的慢性疼痛微创治疗的研究。③软组织损伤引起的慢性疼痛运动疗法的研究。④软组织损伤引起的慢性疼痛心理治疗的研究。⑤软组织损伤引起的慢性疼痛其他疗法的研究。排除重复性研究的文献。资料提炼:共收集到40篇关于软组织损伤引起的慢性疼痛治疗方法的文献,均为全文,23篇符合纳入标准,排除17篇重复性研究。同时录入书籍3本。资料综合:软组织损伤引起的慢性疼痛的产生是生理、心理及社会因素复杂结合的结果,个体表现差异较大,目前尚无特效治疗方法,常用的治疗方法有:药物治疗、微创治疗、运动疗法、心理治疗、物理疗法及其他疗法。结论:对于软组织损伤引起的慢性疼痛的治疗必须以整体的观点对其进行合理的评估和个体化治疗,才能收到良好的效果。  相似文献   
20.
随着对胃食管反流病研究的深入,大脑和食管感觉及胃排空的相互作用越来越受到重视,功能磁共振成像技术,有助于进一步了解胃食管反流病的发病机制。  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