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   5546篇
  免费   331篇
  国内免费   15篇
耳鼻咽喉   41篇
儿科学   131篇
妇产科学   104篇
基础医学   705篇
口腔科学   391篇
临床医学   479篇
内科学   1165篇
皮肤病学   92篇
神经病学   438篇
特种医学   195篇
外科学   865篇
综合类   24篇
一般理论   2篇
预防医学   367篇
眼科学   83篇
药学   429篇
中国医学   16篇
肿瘤学   365篇
  2023年   28篇
  2022年   35篇
  2021年   83篇
  2020年   61篇
  2019年   73篇
  2018年   126篇
  2017年   100篇
  2016年   120篇
  2015年   137篇
  2014年   144篇
  2013年   265篇
  2012年   378篇
  2011年   370篇
  2010年   246篇
  2009年   238篇
  2008年   332篇
  2007年   334篇
  2006年   347篇
  2005年   372篇
  2004年   361篇
  2003年   347篇
  2002年   317篇
  2001年   46篇
  2000年   35篇
  1999年   63篇
  1998年   76篇
  1997年   52篇
  1996年   43篇
  1995年   51篇
  1994年   39篇
  1993年   29篇
  1992年   38篇
  1991年   42篇
  1990年   29篇
  1989年   32篇
  1988年   33篇
  1987年   37篇
  1986年   29篇
  1985年   38篇
  1984年   34篇
  1983年   27篇
  1982年   33篇
  1981年   31篇
  1980年   19篇
  1979年   19篇
  1978年   21篇
  1977年   22篇
  1976年   17篇
  1975年   18篇
  1974年   22篇
排序方式: 共有5892条查询结果,搜索用时 250 毫秒
991.

Study objective

To determine longitudinal trends in mortality, and the contribution of specific injury characteristics and treatment modalities to the risk of a fatal outcome after severe and complex pelvic trauma.

Methods

We studied 5048 patients with pelvic ring fractures enrolled in the German Pelvic Trauma Registry Initiative between 1991 and 1993, 1998 and 2000, and 2004 and 2006. Complete datasets were available for 5014 cases, including 508 complex injuries, defined as unstable fractures with severe peri-pelvic soft tissue and organ laceration. Multivariable mixed-effects logistic regression analysis was employed to evaluate the impact of demographic, injury- and treatment-associated variables on all-cause in-hospital mortality.

Results

All-cause in-hospital mortality declined from 8% (39/466) in 1991 to 5% (33/638) in 2006. Controlling for age, Injury Severity Score, pelvic vessel injury, the need for emergency laparotomy, and application of a pelvic clamp, the odds ratio (OR) per annum was 0.94 (95% confidence interval [CI] 0.91–0.96). However, the risk of death did not decrease significantly in patients with complex injuries (OR 0.98, 95% CI 0.93–1.03). Raw mortality associated with this type of injury was 18% (95% CI 9–32%) in 2006.

Conclusion

In contrast to an overall decline in trauma mortality, complex pelvic ring injuries remain associated with a significant risk of death. Awareness of this potentially life-threatening condition should be increased amongst trauma care professionals, and early management protocols need to be implemented to improve the survival prognosis.  相似文献   
992.
The number of people with normal hearing thresholds seeking medical help for tinnitus and other hearing problems is increasing. For diagnostic purposes, existence/nonexistence of lesions or combinations of lesions in the inner ear not reflected in the audiogram was evaluated with advanced hearing tests applied to tinnitus patients with certain backgrounds, including noise exposure. For forty-six patients with pronounced tinnitus, and other symptoms, tentative diagnoses were established, including judgments of the influence of four causative factors: (1) acoustic trauma, (2) music, (3) suspected hereditary, and (4) nonauditory, for example, stress or muscular tension. They were analyzed with a test battery sensitive to lesions involving the outer hair cells, damage from impulse noise, and dysfunction of the efferent system. There were significant differences in test results between groups with individuals with the same most likely causative factor. Most patients claiming acoustic trauma had a specific type of result, 'hyper-PMTF' (psychoacoustical modulation transfer function), and abnormal test results of the efferent system. Everyone in the hereditary group had dysfunction of the efferent system. All patients working with music, except one, had some abnormality, but without specific pattern. The nonauditory group mostly had normal test results. The investigation shows that it is possible to diagnose minor cochlear lesions as well as dysfunction of the efferent system, which might be causing the tinnitus. Those abnormalities could not be detected with routine audiological tests. Malfunctioning caused by impulse noise is an obvious example of this. These findings facilitate choice of treatment, rehabilitation programs, and medicolegal decisions.  相似文献   
993.
It is essential to catalog characterized hepatitis C virus (HCV) protein-protein interaction (PPI) data and the associated plethora of vital functional information to augment the search for therapies, vaccines and diagnostic biomarkers. In furtherance of these goals, we have developed the hepatitis C virus protein interaction database (HCVpro) by integrating manually verified hepatitis C virus-virus and virus-human protein interactions curated from literature and databases. HCVpro is a comprehensive and integrated HCV-specific knowledgebase housing consolidated information on PPIs, functional genomics and molecular data obtained from a variety of virus databases (VirHostNet, VirusMint, HCVdb and euHCVdb), and from BIND and other relevant biology repositories. HCVpro is further populated with information on hepatocellular carcinoma (HCC) related genes that are mapped onto their encoded cellular proteins. Incorporated proteins have been mapped onto Gene Ontologies, canonical pathways, Online Mendelian Inheritance in Man (OMIM) and extensively cross-referenced to other essential annotations. The database is enriched with exhaustive reviews on structure and functions of HCV proteins, current state of drug and vaccine development and links to recommended journal articles. Users can query the database using specific protein identifiers (IDs), chromosomal locations of a gene, interaction detection methods, indexed PubMed sources as well as HCVpro, BIND and VirusMint IDs. The use of HCVpro is free and the resource can be accessed via http://apps.sanbi.ac.za/hcvpro/ or http://cbrc.kaust.edu.sa/hcvpro/.  相似文献   
994.
Bioactive compounds produced by plants are easily transferred to soil and water and may cause adverse ecosystem effects. Cyclotides are gene-encoded, circular, cystine-rich mini-proteins produced in Violaceae and Rubiaceae in high amounts. Based on their biological activity and stability, cyclotides have promising pharmaceutical and agricultural applications. We report the toxicity of the cyclotides: kalata B1, kalata B2, and cycloviolacin O2 extracted from plants to green algae (Pseudokirchneriella subcapitata), duckweed (Lemna minor L.), lettuce (Lactuca sativa L.), and bacteria extracted from soil measured as [3H]leucine incorporation. Quantification by liquid chromatography-mass spectrometry demonstrated up to 98% loss of cyclotides from aqueous solutions because of sorption to test vials. Sorption was prevented by adding bovine serum albumin (BSA) to the aqueous media. Cyclotides were toxic to all test organisms with EC50 values of 12 through 140 μM (algae), 9 through 40 μM (duckweed), 4 through 54 μM (lettuce), and 7 through 26 μM (bacteria). Cycloviolacin O2 was the most potent cyclotide in all assays examined. This report is the first to document toxic effects of cyclotides in plants and soil bacteria and to demonstrate that cyclotides are as toxic as commonly used herbicides and biocides. Hence, cyclotides may adversely affect soil and aquatic environments, which needs to be taken into account in future risk assessment of cropping systems for production of these highly bioactive compounds.  相似文献   
995.
996.

Purpose  

To investigate the effects of total workload and other work-related factors on postpartum depression in the first 6 months after childbirth, utilizing a hybrid model of health and workforce participation.  相似文献   
997.
Research on social capital and health has assumed that measures of trust, participation, and perceived cohesion capture aspects of people's neighborhood social connections. This study uses data on the personal networks of 2707 Montreal adults in 300 different neighborhoods to examine the association of socio-demographic and social capital variables with the likelihood of having core ties, core neighborhood ties, and high self-rated health (SRH). Persons with higher household income were more likely to have core ties, but less likely to have core neighborhood ties. Persons with greater diversity in extra-neighborhood network capital were more likely to have core ties, and persons with greater diversity in intra-neighborhood network capital were more likely to have core neighborhood ties. Generalized trust, perceived neighborhood cohesion, and extra-neighborhood network diversity were shown associated with high SRH. Conventional measures of social capital may not capture network mechanisms. Findings suggest a critical appraisal of the mechanisms linking social capital and health, and the further delineation of network and psychosocial mechanisms in understanding these links.  相似文献   
998.
We aimed to review and summarize the evidence from accomplished trials analyzing factors influencing mortality in patients with T2DM and to provide some recommendations for targets and treatment in the European region. The following databases were searched for relevant trials: PubMed and the Cochrane Library. Of 3.806 citations, 134 trials met our inclusion criteria. Results: The reduction in lifetime for 65 + ?years-old patients having less than 10 years T2DM amounts to 1.8 years. Having T2DM for more than 10 years lifetime will be reduced by 2.7 years. However, the lifetime shortening factor of T2DM will even be stronger for 40 + ?years-old patients at onset. Males will lose 11.6 years of life and 18.6 QUALYs. T2DM among females will reduce life by 14 QUALYs by 22 years. From a statistical point of view, the highest mortality rate will occur in an over 55-years-old European smoking and non-compliant diabetic woman with alcohol abuse living in a rural area with a low level of education and a low socio-economic status. Furthermore, other co-morbidities such as cardiovascular diseases, gout, and depression affect mortality. Additionally, mortality will increase with a BMI over 35 and also with a BMI under 20–25. This refers to the obesity paradox indicating a higher mortality rate among normal weight patients with T2DM compared to overweight patients with T2DM. HbA1c-levels between 6.5 % and 7 % are associated with the lowest impact on mortality.  相似文献   
999.
1000.
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