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   2707篇
  免费   158篇
  国内免费   6篇
耳鼻咽喉   15篇
儿科学   76篇
妇产科学   103篇
基础医学   323篇
口腔科学   52篇
临床医学   298篇
内科学   597篇
皮肤病学   36篇
神经病学   254篇
特种医学   89篇
外科学   309篇
综合类   11篇
一般理论   1篇
预防医学   206篇
眼科学   62篇
药学   194篇
中国医学   11篇
肿瘤学   234篇
  2023年   58篇
  2022年   19篇
  2021年   146篇
  2020年   81篇
  2019年   110篇
  2018年   110篇
  2017年   77篇
  2016年   92篇
  2015年   95篇
  2014年   149篇
  2013年   146篇
  2012年   207篇
  2011年   244篇
  2010年   144篇
  2009年   113篇
  2008年   178篇
  2007年   170篇
  2006年   168篇
  2005年   118篇
  2004年   92篇
  2003年   99篇
  2002年   76篇
  2001年   22篇
  2000年   12篇
  1999年   18篇
  1998年   17篇
  1997年   10篇
  1996年   4篇
  1995年   8篇
  1994年   4篇
  1993年   2篇
  1992年   6篇
  1991年   7篇
  1990年   9篇
  1989年   7篇
  1988年   4篇
  1987年   5篇
  1986年   5篇
  1984年   4篇
  1982年   2篇
  1978年   3篇
  1973年   2篇
  1972年   3篇
  1971年   4篇
  1970年   4篇
  1969年   2篇
  1968年   5篇
  1967年   1篇
  1964年   1篇
  1932年   1篇
排序方式: 共有2871条查询结果,搜索用时 609 毫秒
51.
Objective: To evaluate the effectiveness double cervical cerclage in reducing antenatal complications and improve perinatal outcomes.

Methods: We searched Medline, Scopus, Clinicaltrials.org, The Cochrane Central Register of Controlled Trials and Google Scholar search engines.

Results: Six studies were included that involved 880 women. Double cerclage was significantly superior to single cerclage in reducing preterm births <34?weeks (734 cases, OR 0.59, 95% CI 0.40, 0.86) and preterm births <28?weeks (645 cases, OR 0.43, 95% CI 0.26–0.73). It also significantly increased the gestational age (380 cases, MD 2.63, 95% CI 0.87, 4.39). However, as a technique, it failed to improve the rates of preterm births <37?weeks (740 cases, OR 0.98, 95% CI 0.72, 1.34) the incidence of chorioamnionitis (740 cases, OR 0.83, 95% CI 0.51, 1.36) and the occurrence of preterm premature rupture of the membranes (796 cases, OR 1.32, 95% CI 0.95, 1.82).

Conclusions: It seems that double cerclage effectively increases the gestational age at delivery and decreases the rates of extremely premature births. However, as a procedure, it does not reduce the incidence of antenatal morbidity or the neonatal death rates. Further research is needed in the field as our meta-analysis is limited by the small number of enrolled studies.  相似文献   

52.

Background

Stochastic Resonance (SR) Stimulation has been used to enhance balance in populations with sensory deficits by improving the detection and transmission of afferent information. Despite the potential promise of SR in improving postural control, its use in individuals with cerebral palsy (CP) is novel. The objective of this study was to investigate the immediate effects of electrical SR stimulation when applied in the ankle muscles and ligaments on postural stability in children with CP and their typically developing (TD) peers.

Methods

Ten children with spastic diplegia (GMFCS level I- III) and ten age-matched TD children participated in this study. For each participant the SR sensory threshold was determined. Then, five different SR intensity levels (no stimulation, 25, 50, 75, and 90% of sensory threshold) were used to identify the optimal SR intensity for each subject. The optimal SR and no stimulation condition were tested while children stood on top of 2 force plates with their eyes open and closed. To assess balance, the center of pressure velocity (COPV) in anteroposterior (A/P) and medial-lateral (M/L) direction, 95% COP confidence ellipse area (COPA), and A/P and M/L root mean square (RMS) measures were computed and compared.

Results

For the CP group, SR significantly decreased COPV in A/P direction, and COPA measures compared to the no stimulation condition for the eyes open condition. In the eyes closed condition, SR significantly decreased COPV only in M/L direction. Children with CP demonstrated greater reduction in all the COP measures but the RMS in M/L direction during the eyes open condition compared to their TD peers. The only significant difference between groups in the eyes closed condition was in the COPV in M/L direction.

Conclusions

SR electrical stimulation may be an effective stimulation approach for decreasing postural sway and has the potential to be used as a therapeutic tool to improve balance. Applying subject-specific SR stimulation intensities is recommended to maximize balance improvements. Overall, balance rehabilitation interventions in CP might be more effective if sensory facilitation methods, like SR, are utilized by the clinicians.

Trial registration

ClinicalTrials.gov identifier NCT02456376; 28 May 2015 (Retrospectively registered); https://clinicaltrials.gov/ct2/show/NCT02456376.
  相似文献   
53.
54.
55.
Bioinformatics approaches to examine gene‐gene models provide a means to discover interactions between multiple genes that underlie complex disease. Extensive computational demands and adjusting for multiple testing make uncovering genetic interactions a challenge. Here, we address these issues using our knowledge‐driven filtering method, Biofilter, to identify putative single nucleotide polymorphism (SNP) interaction models for cataract susceptibility, thereby reducing the number of models for analysis. Models were evaluated in 3,377 European Americans (1,185 controls, 2,192 cases) from the Marshfield Clinic, a study site of the Electronic Medical Records and Genomics (eMERGE) Network, using logistic regression. All statistically significant models from the Marshfield Clinic were then evaluated in an independent dataset of 4,311 individuals (742 controls, 3,569 cases), using independent samples from additional study sites in the eMERGE Network: Mayo Clinic, Group Health/University of Washington, Vanderbilt University Medical Center, and Geisinger Health System. Eighty‐three SNP‐SNP models replicated in the independent dataset at likelihood ratio test P < 0.05. Among the most significant replicating models was rs12597188 (intron of CDH1)–rs11564445 (intron of CTNNB1). These genes are known to be involved in processes that include: cell‐to‐cell adhesion signaling, cell‐cell junction organization, and cell‐cell communication. Further Biofilter analysis of all replicating models revealed a number of common functions among the genes harboring the 83 replicating SNP‐SNP models, which included signal transduction and PI3K‐Akt signaling pathway. These findings demonstrate the utility of Biofilter as a biology‐driven method, applicable for any genome‐wide association study dataset.  相似文献   
56.
57.

Background

Septic shock is associated with hypovolemia resulting in organs failure and poor prognosis. The first step in hemodynamic resuscitation relies on early fluid expansion. In this study, we describe qualitative and quantitative fluid resuscitation of septic shock initially managed in a pre-hospital setting by a mobile intensive care unit.

Methods

Patients with septic shock who received pre-hospital medical care were retrospectively analysed. Qualitative and quantitative fluid resuscitation performed in the pre-hospital setting were analysed. Applying the "grey zone" concept, we define 3 categories of fluid expansion indexed on ideal body weight (IBW): >20ml/kg, 10-20ml/kg and ?<?10ml/kg. The relationship between the pre-specified categories and mortality at day 28 were analyzed.

Results

Ninety-five patients were included. The origin of sepsis was mainly pulmonary (68%). Mortality reached 34%. Pre-hospital fluid expansion was performed using serum saline (98%) with a mean of 1158±559ml. An inversed linear relationship between pre-specified categories and mortality was observed. Using logistic regression model, significant association with mortality remained for fluid expansion indexed on IBW: p=0.02, ORa [CI95] = 0.93 [0.89-0.98]. For fluid expansion indexed on IBW?<?10ml/kg, the OR [CI95] was 4.03 [1.78-9.41] (p=0.005) whereas for fluid expansion indexed on IBW?>?20ml/kg, the OR [CI95] was 0.30 [0.13-0.66] (p=0.01).

Discussion

Pre-hospital fluid resuscitation in septic shock is mainly performed using crystalloids with quantitative fluid expansion lower than recommended. Low pre-hospital fluid expansion was associated with increased mortality. Further prospective studies are needed to evaluate the impact of optimized early fluid expansion on mortality in the prehospital management of septic shock.  相似文献   
58.
Coenurosis is a disease of the central nervous system in sheep, caused by Coenurus cerebralis, the larval stage of Multiceps multiceps, which inhabits the small intestine of Canidae. A case of regurgitations in a 2.5 month old lamb with acute coenurosis is being reported. The lamb was presented with a sudden onset of ataxia and regurgitations for 10 days. The post-mortem examination revealed 4 immature C. cerebralis cysts between 0.5 and 1.5 cm in diameter located in the brainstem and cerebellum, and histopathological examination revealed multifocal pyogranulomatous meningoencephalitis, so a diagnosis of acute coenurosis was established. Thus, acute coenurosis should be included in the differential diagnosis of regurgitations in lambs.  相似文献   
59.
60.
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