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   2322篇
  免费   181篇
  国内免费   4篇
耳鼻咽喉   61篇
儿科学   224篇
妇产科学   78篇
基础医学   341篇
口腔科学   20篇
临床医学   249篇
内科学   485篇
皮肤病学   68篇
神经病学   176篇
特种医学   65篇
外国民族医学   7篇
外科学   268篇
综合类   25篇
预防医学   190篇
眼科学   10篇
药学   147篇
肿瘤学   93篇
  2021年   28篇
  2020年   14篇
  2019年   28篇
  2018年   43篇
  2017年   34篇
  2016年   24篇
  2015年   27篇
  2014年   37篇
  2013年   77篇
  2012年   117篇
  2011年   115篇
  2010年   52篇
  2009年   65篇
  2008年   111篇
  2007年   128篇
  2006年   99篇
  2005年   122篇
  2004年   122篇
  2003年   92篇
  2002年   101篇
  2001年   64篇
  2000年   81篇
  1999年   71篇
  1998年   26篇
  1997年   25篇
  1996年   21篇
  1995年   16篇
  1994年   24篇
  1993年   20篇
  1992年   62篇
  1991年   58篇
  1990年   52篇
  1989年   54篇
  1988年   34篇
  1987年   41篇
  1986年   32篇
  1985年   35篇
  1984年   29篇
  1983年   34篇
  1982年   15篇
  1980年   17篇
  1979年   18篇
  1978年   17篇
  1977年   19篇
  1976年   16篇
  1975年   12篇
  1974年   24篇
  1973年   17篇
  1968年   16篇
  1967年   11篇
排序方式: 共有2507条查询结果,搜索用时 22 毫秒
1.
This retrospective cohort study deals with the causes of death among 57,000 military personnel who served in the French Navy surface vessels and were observed over the period 1975–2000. We successively compared the mortality rate and the specific causes of death between two groups differing in their potential exposure levels to radar. Occupational exposure was defined according to the on-board workplace (radar and control groups). The age-adjusted death ratios of the navy personnel were compared. For all causes of death, the results showed that 885 deaths in the radar group and 299 in the control group occurred (RR = 1.00 (95?% CI: 0.88–1.14)). RRs were 0.92 (95?% CI: 0.69–1.24) for neoplasms. For the duration of follow-up, the results did not show an increased health risk for military personnel exposed to higher levels of radio frequencies in the radar group, but the number of deaths was very small for some cancer sites.  相似文献   
2.
Since 2000, French Corsica Island has been exposed to the emergence of three different BT virus (BTV) serotypes: serotype 2 in 2000 and 2001, serotype 4 in 2003 and serotype 16 in 2004. Between 2005 and August 2013, no outbreaks have been reported in the French Island. At the beginning of September 2013, sheep located in the south of the island showed clinical signs suggestive of BTV infection. Laboratory analyses identified the virus as BTV serotype 1. Phylogenetic studies showed that the sequences of this strain are closely related to the BTV‐1 strain that was circulating in the Mediterranean basin and in Sardinia in 2012.  相似文献   
3.
4.
5.
PurposeBiallelic loss-of-function variants in ST3GAL5 cause GM3 synthase deficiency (GM3SD) responsible for Amish infantile epilepsy syndrome. All Amish patients carry the homozygous p.(Arg288Ter) variant arising from a founder effect. To date only 10 patients from 4 non-Amish families have been reported. Thus, the phenotypical spectrum of GM3SD due to other variants and other genetic backgrounds is still poorly known.MethodsWe collected clinical and molecular data from 16 non-Amish patients with pathogenic ST3GAL5 variants resulting in GM3SD.ResultsWe identified 12 families originating from Reunion Island, Ivory Coast, Italy, and Algeria and carrying 6 ST3GAL5 variants, 5 of which were novel. Genealogical investigations and/or haplotype analyses showed that 3 of these variants were founder alleles. Glycosphingolipids quantification in patients’ plasma confirmed the pathogenicity of 4 novel variants. All patients (N = 16), aged 2 to 12 years, had severe to profound intellectual disability, 14 of 16 had a hyperkinetic movement disorder, 11 of 16 had epilepsy and 9 of 16 had microcephaly. Other main features were progressive skin pigmentation anomalies, optic atrophy or pale papillae, and hearing loss.ConclusionThe phenotype of non-Amish patients with GM3SD is similar to the Amish infantile epilepsy syndrome, which suggests that GM3SD is associated with a narrow and severe clinical spectrum.  相似文献   
6.
7.
A double-blind crossover study was conducted in four CYP2C19 genotype-defined metabolizer groups to assess whether increase in clopidogrel dosing can overcome reduced pharmacodynamic response in CYP2C19 poor metabolizers (PMs). Ten healthy subjects in each of four metabolizer groups were randomized to a clopidogrel regimen of a 300-mg loading dose (LD) and a 75-mg/day maintenance dose (MD) for 4 days followed by 600-mg LD and 150 mg/day MD, or vice versa. The exposure levels of clopidogrel's active metabolite H4 (clopi-H4) in PMs were 71% lower on the 75-mg/day regimen and 64% lower on the 150-mg/day regimen than the corresponding exposure levels in extensive metabolizers (EMs). In PMs, the maximal platelet aggregation (MPA) induced by adenosine diphosphate (ADP) 5 μmol/l was 10.5% lower on the 75-mg/day regimen and 7.9% lower on the 150-mg/day regimen than the corresponding values in EMs. PMs who were on the clopidogrel regimen of 600-mg LD/150 mg/day MD showed clopi-H4 exposure and MPA levels similar to those in EMs who were on the regimen of 300-mg LD/75 mg/day MD. In a pooled analysis evaluating CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP3A5, CYP2D6, ABCB1, and P2RY12 polymorphisms (N = 396 healthy subjects), only CYP2C19 had a significant impact on antiplatelet response. In healthy CYP2C19 PMs, a clopidogrel regimen of 600-mg LD/150 mg/day MD largely overcomes diminished clopi-H4 exposure and antiplatelet response, as assessed by MPA levels.  相似文献   
8.

Background

Stroke is a primary cause of death and disability in upper-middle–income countries such as Colombia. Given the lack of comprehensive rehabilitation for stroke patients in Colombia, there is a need to assess longitudinal mental health problems poststroke in this region.

Objective

To compare the course of mental health in stroke patients to healthy controls over the first year poststroke in Ibague, Colombia.

Design

Cross-sectional study.

Setting

The Psychological Attention Center of Antonio Nariño University in Ibague, Colombia.

Participants

Stroke patients (n = 50) and age- and gender-matched healthy controls (n = 50).

Methods

Patients and controls completed self-report Spanish versions of demographic information, injury-related characteristics, and mental health questionnaires

Main Outcome Measurements

Outcomes assessed included mental health (depression, anxiety, and stress) at 3, 6, and 12 months poststroke.

Results

Hierarchical linear models suggested that stroke patients had worse depression and anxiety over time than controls (P < .001). Among patients, depression and anxiety decreased over time (P < .001), whereas stress increased over time (P < .01). The findings suggest that although anxiety and depression improved over time in stroke patients, their mental health remained significantly lower than that of controls.

Conclusions

This is the first study to examine the course of mental health over the first year poststroke in Latin America, specifically in Ibague, Colombia. Despite the improvements in anxiety and depression over the first year poststroke, patient anxiety and depression were still worse in comparison to those in healthy controls. The current findings indicate a need for rehabilitation services in Colombia, especially targeting mental health issues.

Level of Evidence

I  相似文献   
9.
Saimiri monkeys immunized with a Plasmodium falciparum merozoite polypeptide of 41 kD mol wt are resistant to a blood challenge infection that induces a fulminant infection in control monkeys. The sera of the immunized monkeys reacted, as shown by the indirect immunofluorescence technique, with the apical part of the merozoites from five isolates or clones of P. falciparum. Whether the immunogen was dissolved in nonionic detergent (NP-40) or in sodium dodecyl sulfate (SDS) had a marked influence on the level of protection in immunized monkeys. Thus, monkeys immunized with the antigen solubilized in a nonionic detergent developed much lower parasitemia than monkeys immunized with denatured antigen (antigen eluted from SDS polyacrylamide gel electrophoresis).  相似文献   
10.
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