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   746篇
  免费   54篇
  国内免费   2篇
耳鼻咽喉   6篇
儿科学   28篇
妇产科学   8篇
基础医学   95篇
口腔科学   4篇
临床医学   42篇
内科学   250篇
皮肤病学   18篇
神经病学   38篇
特种医学   11篇
外科学   89篇
综合类   39篇
预防医学   43篇
眼科学   12篇
药学   71篇
中国医学   2篇
肿瘤学   46篇
  2023年   4篇
  2022年   8篇
  2021年   21篇
  2020年   9篇
  2019年   7篇
  2018年   8篇
  2017年   11篇
  2016年   11篇
  2015年   12篇
  2014年   14篇
  2013年   25篇
  2012年   35篇
  2011年   45篇
  2010年   19篇
  2009年   17篇
  2008年   40篇
  2007年   27篇
  2006年   34篇
  2005年   32篇
  2004年   22篇
  2003年   28篇
  2002年   28篇
  2001年   23篇
  2000年   24篇
  1999年   23篇
  1998年   14篇
  1996年   12篇
  1995年   7篇
  1994年   7篇
  1993年   4篇
  1992年   30篇
  1991年   28篇
  1990年   21篇
  1989年   8篇
  1988年   12篇
  1987年   11篇
  1985年   14篇
  1984年   12篇
  1983年   8篇
  1981年   3篇
  1979年   4篇
  1978年   4篇
  1975年   3篇
  1974年   5篇
  1972年   12篇
  1971年   5篇
  1970年   7篇
  1969年   9篇
  1967年   10篇
  1966年   5篇
排序方式: 共有802条查询结果,搜索用时 15 毫秒
71.
Globally, Salmonella enterica subsp. enterica is one of the most commonly reported causes of foodborne illness in humans. Contaminated food products of animal origin, particularly egg and egg products are frequently implicated in outbreaks of human salmonellosis. Salmonella enteritidis is frequently involved in egg and egg products-associated foodborne outbreaks in the USA and UK. However, in Australia and New Zealand, human infections caused by this serovar occur as a result of infection acquired while overseas travel, with Salmonella typhimurium being a predominant cause of local foodborne outbreaks. In this paper, an overview of Salmonella epidemiology on laying farms, egg-related Salmonella outbreaks in humans, and regulatory practises to control Salmonella across USA, UK, Australia and New Zealand is provided. Considering the estimated production of eggs in the USA, UK, Australia and New Zealand in 2015, the risk of foodborne illness in general is quite low for humans consuming eggs. Salmonella diagnostics, reporting and surveillance systems have improved over the years and will continue to improve in the years to come. However, given the number of different emerging Salmonella serovars a regular review of Salmonella control strategies from farm to fork is required.  相似文献   
72.
Physics-based simulation provides a powerful framework for understanding biological form and function. Simulations can be used by biologists to study macromolecular assemblies and by clinicians to design treatments for diseases. Simulations help biomedical researchers understand the physical constraints on biological systems as they engineer novel drugs, synthetic tissues, medical devices, and surgical interventions. Although individual biomedical investigators make outstanding contributions to physics-based simulation, the field has been fragmented. Applications are typically limited to a single physical scale, and individual investigators usually must create their own software. These conditions created a major barrier to advancing simulation capabilities. In 2004, we established a National Center for Physics-Based Simulation of Biological Structures (Simbios) to help integrate the field and accelerate biomedical research. In 6 years, Simbios has become a vibrant national center, with collaborators in 16 states and eight countries. Simbios focuses on problems at both the molecular scale and the organismal level, with a long-term goal of uniting these in accurate multiscale simulations.  相似文献   
73.
A large program was conducted by the Government of India to study the prevalence and profile of chronic hepatitis B virus (HBV) infection and its risk factors in pregnant women attending a tertiary care hospital in India. From September 2004 to December 2008 consecutive pregnant women attending the antenatal clinic were screened and those found positive for HBsAg were enrolled. Healthy non‐pregnant women of child‐bearing age, who presented for blood donation during the same period, served as controls. Women with symptoms of liver disease or those aware of their HBsAg status were excluded. Of the 20,104 pregnant women screened, 224 (1.1%) and of the 658 controls, 8 (1.2%) were HBsAg positive (P = ns). Previous blood transfusions and surgery were significant risk factors for infection with HBV. Of the women who were HBsAg positive, the ALT levels were normal in 54% of the women and HBV DNA levels were above 2,000 IU/ml in 71% of women. The median HBV DNA levels were higher in women who were HBeAg positive compared to the HBeAg negative group. The most common HBV genotype was D (84%) followed by A + D and A (8% each). In conclusion, the prevalence of HBsAg positivity among asymptomatic pregnant women in North India is 1.1% with 71% having high HBV DNA levels. These women may have a high risk of transmitting infection to their newborns. J. Med. Virol. 83:962–967, 2011. © 2011 Wiley‐Liss, Inc.  相似文献   
74.

Summary  

Fall risk does not significantly impact on the efficacy of the bisphosphonate clodronate in reducing the incidence of fracture.  相似文献   
75.

Summary

Fracture risk prediction can be enhanced by the concurrent assessment of other clinical risk factors. This study demonstrates that the estimation of an individual’s 10-year probability of fracture by the FRAX® algorithm identifies patients at high risk of fracture who will respond to bisphosphonate therapy.

Introduction

Treatments for osteoporosis are targeted largely to patients with low bone density (BMD) or a prior fragility fracture. Fracture risk prediction can be enhanced by the concurrent assessment of other clinical risk factors, but it is important to determine whether the risk so identified can be reduced by intervention. We determined the effect of a bisphosphonate on fracture rates when risk was calculated using a new risk algorithm (FRAX®).

Methods

Women aged 75 years or more were recruited to a randomised, double-blind controlled trial of 800 mg oral clodronate (Bonefos®) daily over 3 years. Baseline clinical risk factors were entered in the FRAX® model to compute the 10-year probability of major osteoporotic fractures with or without input of femoral neck BMD. The interaction between fracture probability and treatment efficacy was examined by Poisson regression.

Results

In 3,974 women, the interaction between fracture probability and treatment efficacy was significant when probability was assessed without BMD (p?=?0.043), but not when BMD was included (p?=?0.10). Efficacy was more evident in those deemed at highest risk. For example women lying at the 75th percentile of fracture probability in the absence of BMD (10-year probability 24%) treatment reduced fracture risk by 27% (HR 0.73, 95%CI 0.58–0.92). In those with a fracture probability of 30% (90th percentile), the fracture risk reduction was 38% (HR 0.62, 0.46–0.84).

Conclusions

The estimation of an individual’s 10-year probability of fracture by the FRAX® algorithm identifies patients at high risk of fracture who will respond to bisphosphonate therapy.  相似文献   
76.
77.
Gill K  Pande R  Malhotra A 《Lancet》2007,370(9595):1347-1357
There is a large amount of research into maternal health as a health issue, but maternal health as a development issue has been less explored. This Review analyses the evidence from the past 20 years on the links between maternal health and development to examine maternal health within a development framework. We note that although existing evidence suggests that these links are strong, further research is needed to definitively substantiate how and to what extent maternal health and development affect each other. Further, we find that progress and investment in maternal health have lagged far behind estimates of what is needed to achieve the Millennium Development Goals.  相似文献   
78.
The P23T mutant of human gammaD-crystallin (HGD) is associated with cataract. We have previously investigated the solution properties of this mutant, as well as those of the closely related P23V and P23S mutants, and shown that although mutations at site 23 of HGD do not produce a significant structural change in the protein, they nevertheless profoundly alter the solubility of the protein. Remarkably, the solubility of the mutants decreases with increasing temperature, in sharp contrast to the behavior of the native protein. This inverted solubility corresponds to a strong increase in the binding energy with temperature. Here we have investigated the liquid-liquid coexistence curve and the diffusivity of the P23V mutant and find that these solution properties are unaffected by the mutation. This means that the chemical potentials in the solution phase are essentially unaltered. The apparent discrepancy between the interaction energies in the solution phase, as compared with the solid phase, is explicable in terms of highly anisotropic interprotein interactions, which are averaged out in the solution phase but are fully engaged in the solid phase.  相似文献   
79.
80.
Lung malignancy extending into left atrium is seen very infrequently. We had a patient with a fast growing symptomatic lung mass and electrocardiogram showing persistent coving ST elevation without any biomarker change. Transthoracic echocardiography showed a large left atrial mass which was fixed to the free walls and extended into the appendage. There was also a large lung mass that was compressing the heart from its lateral aspect. CT-scan of chest corroborated the lung mass & CT-guided FNAC showed small cell carcinoma.  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