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   2716篇
  免费   221篇
  国内免费   7篇
耳鼻咽喉   5篇
儿科学   79篇
妇产科学   41篇
基础医学   485篇
口腔科学   15篇
临床医学   301篇
内科学   585篇
皮肤病学   79篇
神经病学   349篇
特种医学   62篇
外科学   233篇
综合类   5篇
预防医学   196篇
眼科学   32篇
药学   174篇
中国医学   1篇
肿瘤学   302篇
  2024年   2篇
  2023年   25篇
  2022年   36篇
  2021年   100篇
  2020年   66篇
  2019年   85篇
  2018年   105篇
  2017年   76篇
  2016年   68篇
  2015年   96篇
  2014年   113篇
  2013年   125篇
  2012年   247篇
  2011年   249篇
  2010年   126篇
  2009年   129篇
  2008年   203篇
  2007年   199篇
  2006年   165篇
  2005年   165篇
  2004年   144篇
  2003年   138篇
  2002年   104篇
  2001年   20篇
  2000年   20篇
  1999年   22篇
  1998年   20篇
  1997年   12篇
  1996年   11篇
  1995年   7篇
  1994年   7篇
  1993年   8篇
  1992年   5篇
  1991年   7篇
  1990年   9篇
  1989年   5篇
  1988年   5篇
  1987年   12篇
  1986年   5篇
  1985年   2篇
  1975年   1篇
排序方式: 共有2944条查询结果,搜索用时 15 毫秒
91.
92.
After performing a V-Y advancement flap, we observed an unusually shaped necrosis, resembling a keyhole at the apex of the flap. As high closing tensions are an accepted cause of skin necrosis, we developed a mathematical model based on the finite element analysis in order to determine the stress field by simulating the mechanical behavior of human skin during suture and to explain this particular shape of necrosis. For the modeling, a planar nonlinear two-dimensional finite element model was used. The numerical simulation was carried out with Ansys® v12 software. Results are expressed in numerical and graphic form. The shape of the vertical iso-stress line for a stress equal to 18.8 kPa was similar to the necrosis observed in our clinical case. Similarities between the shape of necrosis and the calculated stress field at the apex of the V-Y advancement flap indicate the major role of skin tension in this necrosis. Finite element analysis is an original approach for describing the particular shape of a necrosis. Although many factors can be implicated in skin necrosis, the modeling confirms the role of tension in the necrosis of this particular case. Level of Evidence: Level V, risk/prognostic study  相似文献   
93.
The risk of recurrent venous thromboembolism (VTE) in young women after a first oestrogen contraception associated VTE episode is unknown. This uncertainty has an impact on the decision whether to stop anticoagulant treatment. Our objective was to assess the risk of recurrent VTE in women after a first VTE episode on oestrogen contraception. This was a prospective cohort study in which we consecutively enrolled between 1992 and 2011 all women under 50 years with a first objectively confirmed VTE. The incidence of recurrent VTE during follow-up after stopping anticoagulation was compared between women users and non-users of combined oral contraception (COC) at the time of index VTE. Of the 241 women aged 50 or younger seen for a first VTE and followed-up after stopping anticoagulation, there were 180 COC-users and 61 non-users. Median duration of follow-up off-anticoagulants was 66 months (interquartile range: 33–103). There were 14 recurrences in COC-users and 5 cases in non-users. No significant association was found between exposure to COC and the incidence of recurrent VTE after adjustment for age or after restricting the analysis to major unprovoked VTE: incidence rate of recurrence 17.9/1,000/year (95% CI: 9.6-33.2) in women with COC as compared with 17.6/1,000/year (95% CI: 6.6-47) with an incidence ratio of 0.7 (95% CI: 0.2-2.4, p = 0.59). The risk of recurrent VTE is low in young women after a first VTE. However, this risk is not significantly lower in women after a first VTE while exposed to combined oral contraception.  相似文献   
94.
95.
Neurological Sciences - In Parkinson’s disease (PD), non-motor fluctuations (NMFs), especially neuropsychiatric fluctuations, often coexist with motor fluctuations (MFs) but are often...  相似文献   
96.
An estimated 60% of kidney transplant recipients have mineral bone disease and about 0.5% break their hip within the first year after transplantation. We conducted a systematic review of benefits and harms of bisphosphonates in kidney transplant recipients. We searched CENTRAL (Issue 5, 2015) for randomized controlled trials in all languages and screened the reference list of an earlier Cochrane review. One reviewer identified the trials, extracted all data, and assessed risk of bias. Meta‐analysis used a random effects model, with results expressed as risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI). Bisphosphonates have uncertain effects on death (RR 0.45, CI 0.04–4.69) and vertebral fractures (RR 0.58, CI 0.24–1.43, I2 0%). Bisphosphonates moderately to importantly reduce the loss of vertebral bone mineral density (MD 5.98%, CI 3.77–8.18% change from baseline in g calcium/cm² at 12 months, I2 91%) and femoral bone mineral density (MD 5.57%, 3.12–8.01% change from baseline in g calcium/cm² at 12 months, I2 69%). At this stage, insufficient evidence exists to support routine use of bisphosphonates to reduce fracture risk after kidney transplantation. Data on important health outcomes are lacking, surrogate outcomes poorly reflect bone quality in kidney transplant recipients, and serious adverse events are not studied and reported systematically.  相似文献   
97.
98.
BACKGROUND: Delineating asthma subphenotypes is of interest to understand the cause of the disease. Few studies have addressed the interrelationships of quantitative asthma-related traits. OBJECTIVE: We sought to study the interrelationships of allergy markers and FEV(1) in relation to asthma and sex in children and adults. METHODS: Total IgE levels, skin prick test (SPT) positivity, eosinophil counts, and FEV(1) were assessed in 299 asthmatic cases (children and adults) recruited in chest clinics and 309 nonasthmatic population-based control subjects in the French Epidemiological Study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy. RESULTS: Allergy parameters were significantly higher in asthmatic cases than in control subjects for children and adults and for both sexes. Sex and age modified the pattern of concordance of high IgE levels, SPT positivity, and eosinophilia among asthmatic cases, with the greatest overlap in male children (64%) and the lowest in male adults (18%). Patterns of change over the lifespan of IgE levels, eosinophil counts, and FEV(1)/height(2) varied, with the acceleration of FEV(1) decrease being particularly evident in asthmatic adults. In adult cases and control subjects, SPT positivity (particularly to indoor allergens) was significantly related to IgE levels but not to eosinophil counts. The association of eosinophil counts with IgE levels was evident only in children. Environmental factors (smoking, pets, and country living) did not alter the patterns observed. CONCLUSIONS: Each allergy-related phenotype showed a distinct relation with asthma, with the role for eosinophils being different than that for IgE levels and SPT responses. CLINICAL IMPLICATIONS: Taking age and sex into account is essential for understanding the interrelationships of the various allergy-related phenotypes to asthma status.  相似文献   
99.
This article describes a twinning relationship between the Canadian Association of Midwives (CAM) and the Tanzania Midwives Association (TAMA). It argues that the twinning relationship strengthened both associations. The article briefly reviews the existing literature on professional associations and association strengthening to demonstrate that professional associations are a vital tool for improving the performance of healthcare workers and increasing their capacity to contribute to national and international policy-making. It then suggests that midwifery associations are particularly significant given the frequent professional marginalization of midwives. The article then describes in depth the relationship between CAM and TAMA, highlighting the accomplishments of the twinned partners, and analyzing the factors that contributed to the success of the relationship. The findings demonstrate that twinning can successfully strengthen associations, increasing their ability to support their membership, care for the public, and shape national policy-making. The article therefore proposes twinning as a successful and cost-effective model for encouraging the growth of the midwifery profession.  相似文献   
100.

Purpose

Metabolic syndrome (MetS), a multicomponent condition, is a cardiovascular disease predictor. Although exposure to agricultural pesticides has been suggested as a potential contributor to the rising rates of obesity, type 2 diabetes, and other features of metabolic disorders, no studies have focused on the association between consumption of organic food (produced without synthetic pesticides) and MetS. We aimed to investigate the cross-sectional association between organic food consumption and MetS in French adults to determine whether it would be worth conducting further studies, particularly large prospective and randomised trials.

Methods

A total of 8174 participants from the NutriNet-Santé study who attended a clinical visit and completed an organic food frequency questionnaire were included in this cross-sectional analysis. We evaluated the association between the proportion of organic food in the diet (overall and by food group) and MetS using Poisson regression models while adjusting for potential confounders.

Results

Higher organic food consumption was negatively associated with the prevalence of MetS: adjusted prevalence ratio was 0.69 (95% CI 0.61, 0.78) when comparing the third tertile of proportion of organic food in the diet with the first one (p value <0.0001). Higher consumption of organic plant-based foods was also related to a lower probability of having MetS. In addition, when stratifying by lifestyle factors (nutritional quality of the diet, smoking status, and physical activity), a significant negative association was detected in each subgroup (p values <0.05), except among smokers.

Conclusions

Our results showed that a higher organic food consumption was associated with a lower probability of having MetS. Additional prospective studies and randomised trials are required to ascertain the relationship between organic food consumption and metabolic disorders.
  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