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   11273篇
  免费   734篇
  国内免费   62篇
耳鼻咽喉   103篇
儿科学   309篇
妇产科学   228篇
基础医学   1635篇
口腔科学   255篇
临床医学   992篇
内科学   2572篇
皮肤病学   424篇
神经病学   1131篇
特种医学   263篇
外科学   931篇
综合类   57篇
现状与发展   1篇
一般理论   3篇
预防医学   1351篇
眼科学   217篇
药学   780篇
中国医学   50篇
肿瘤学   767篇
  2024年   11篇
  2023年   139篇
  2022年   269篇
  2021年   506篇
  2020年   260篇
  2019年   430篇
  2018年   519篇
  2017年   315篇
  2016年   302篇
  2015年   375篇
  2014年   526篇
  2013年   639篇
  2012年   982篇
  2011年   945篇
  2010年   549篇
  2009年   445篇
  2008年   714篇
  2007年   705篇
  2006年   601篇
  2005年   639篇
  2004年   546篇
  2003年   504篇
  2002年   453篇
  2001年   68篇
  2000年   28篇
  1999年   74篇
  1998年   74篇
  1997年   60篇
  1996年   56篇
  1995年   49篇
  1994年   27篇
  1993年   38篇
  1992年   26篇
  1991年   22篇
  1990年   14篇
  1989年   7篇
  1988年   12篇
  1987年   8篇
  1986年   7篇
  1985年   7篇
  1984年   14篇
  1983年   13篇
  1982年   7篇
  1981年   8篇
  1980年   7篇
  1979年   6篇
  1978年   7篇
  1977年   6篇
  1974年   5篇
  1968年   4篇
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
131.
While assessing immunization programmes, not only vaccination coverage is important, but also timely receipt of vaccines. We estimated both vaccination coverage and timeliness, as well as reasons for non-vaccination, and identified predictors of delayed or missed vaccination, for vaccines of the first two years of age, in El Salvador.  相似文献   
132.
Patients with severe mental illness have higher prevalences of cardiovascular risk factors (CRF). The objective is to determine whether interventions to modify lifestyles in these patients reduce anthropometric and analytical parameters related to CRF in comparison to routine clinical practice. Systematic review of controlled clinical trials with lifestyle intervention in Medline, Cochrane Library, Embase, PsycINFO and CINALH. Change in body mass index, waist circumference, cholesterol, triglycerides and blood sugar. Meta-analyses were performed using random effects models to estimate the weighted mean difference. Heterogeneity was determined using i2 statistical and subgroups analyses. 26 studies were selected. Lifestyle interventions decrease anthropometric and analytical parameters at 3 months follow up. At 6 and 12 months, the differences between the intervention and control groups were maintained, although with less precision. More studies with larger samples and long-term follow-up are needed.  相似文献   
133.
ObjectiveTo describe the use of the Internet by primary care patients to seek health related information, understand how they are influenced by this information, and evaluate its impact on the doctor-patient relationship.DesignCross sectional study, through self-administered survey.SettingOne urban health center in Madrid.ParticipantsA total of 323 questionnaires were collected from patients between 14 and 75 years old who attended a physician's office for any reason, excluding illiterate patients and those with neurological or psychiatric problems preventing them from completing the survey.MeasurementsInternet usage, ability of the internet to clarify doubts regarding health issues, patient lifestyle changes, socio-demographic variables, and physician's receptivity to the use of internet by patients.Results61% (CI 95%: 56%-67%) of patients used the Internet as a source of health information: Internet queries were able to address health doubts in 92.4% of users, 53.5% reported that the Internet changed their thinking about their health in at least one instance, 30% made behavioral changes (of which 60.1% discussed these changes with their physician), 44.3% had more questions at the physician's office, and 80.8% believe that the doctor would be willing to talk about the information found on the internet.ConclusionsUsing the Internet to find information about health is very common, with positive influence on physician-patient relationship. This may be useful for achieving behavioral changes in patients and can be used as a tool in medical practice.  相似文献   
134.
ObjectiveTo investigate the role of low-grade inflammation and insulin resistance (HOMA2-IR) in adiposity-related increases in serum complement factor 3 (C3). Although C3 has been linked to type 2 diabetes and cardiovascular diseases, and C3 levels are closely related to body fat, the underlying mechanisms explaining this association are still unknown.MethodsAdiposity measures (including BMI, waist circumference (WC), sagittal diameter and several skinfolds), HOMA2-IR and markers of inflammation (hs-CRP, IL-6, SAA, haptoglobin, ceruloplasmin, sICAM-1) were determined in 532 individuals (62% men, mean age 59 ± 6.9 yrs) from the Cohort on Diabetes and Atherosclerosis Maastricht study. Markers of inflammation were standardized and compiled into an averaged inflammation score. Cross-sectional associations between adiposity measures and C3 and the mediating role of low-grade inflammation and/or HOMA2-IR herein were analysed with multiple linear regression models.ResultsAdiposity measurements were significantly associated with C3 levels, with the strongest (adjusted) associations found for WC (β = 0.383; 95%CI 0.302–0.464) and sagittal diameter (β = 0.412; 95%CI 0.333-0.490). Further adjustment for inflammation and HOMA2-IR attenuated these associations to β = 0.115 (95%CI 0.030-0.200) and β = 0.163 (95%CI 0.082-0.244) respectively. Multiple mediation analyses showed that inflammation [β = 0.090 (95%CI 0.060–0.126)] and HOMA2-IR [β = 0.179 (95%CI 0.128–0.236)] each explained, independently of one another, a significant portion of the association between WC and C3 (23% and 47%, respectively). Similar mediation by inflammation (19-27%) and HOMA2-IR (37-56%) was found for other adiposity measures.ConclusionSystemic low-grade inflammation and insulin resistance may represent two independent pathways by which body fat leads to elevated C3 levels.  相似文献   
135.
ObjectivesTo describe and compare sexuality between subjects with diabetes with matched non-diabetic controls.MethodsPopulation based case control study using individual data from the Spanish National Sexual Health Survey. Diabetes status was self reported, we selected type 2 patients. We identified 461 diabetes sufferers. Two controls were matched by age, sex and sexual partner for each diabetic case.Sexuality measures included: sexual activity, importance of sex, satisfaction with partner, bothersome with one's sexual life and self-rated sexual health. Independent variables included: socio-demographics, physical health, chronic diseases and medications use.ResultsNo differences were found in “Sexually activity”, “Importance of sex” or “Bothersome” between those with and without diabetes. Dissatisfaction with partner was 25% in women with diabetes and 12.9% in non-diabetic controls (Adjusted-OR 1.82 95%CI 1.02–4.85).Diabetes sufferers reported sexual health as “fair/poor/very poor” more than their non-diabetic control, 58.1% vs. 45.1% for women (Adjusted-OR 1.74 95%CI 1.15–2.63) and 54.3% vs. 38% for men (Adjusted-OR 1.88 95%CI 1.29–2.75).Among diabetes sufferers “fair/poor/very poor” sexual health was associated with poorer physical health, not having a sexual partner and among men taking heart medications.ConclusionsWomen and men with diabetes have significantly worse sexuality measures than non diabetic controls.  相似文献   
136.
Enzyme linked fluorescent assays (VIDAS EBV VCA IgM, VIDAS EBV VCA/EA IgG and VIDAS EBV EBNA IgG (Biomérieux, France) were evaluated to determine markers for infection of Epstein Barr virus, as well as to establish antibody profiles, compared with immunofluorescence assays as reference. The assays evaluated showed good values for sensitivity, specificity and agreement, making them useful for their application in clinical laboratories.  相似文献   
137.
The extracellular matrix of bacterial biofilms has at least two key functions: to serve as a structural scaffold for the multicellular community, and to play a protective role against external stress. In this work, we report a compensatory effect whereby Pseudomonas putida reacts to the lack of either of the two main surface proteins involved in biofilm formation, LapA and LapF, by increasing expression and production of a species-specific EPS. Elevated levels of the second messenger molecule cyclic di-GMP alter the balance of extracellular matrix components, and the phenotypes of lapA and lapF mutants under these conditions are indicative of direct interactions taking place between large secreted proteins and exopolysaccharides. Our data suggest the existence of a mechanism by which bacteria would sense alterations in the composition of the extracellular matrix, leading to changes in expression of the different elements.  相似文献   
138.
Aim of the current study was to evaluate the inter‐observer agreement between pathologists in the diagnosis of celiac disease (CD), in the qualified context of a multicenter study. Biopsies from the “PreventCD” study, a multinational‐ prospective‐ randomized study in children with at least one‐first‐degree relative with CD and positive for HLA‐DQ2/HLA‐DQ8. Ninety‐eight biopsies were evaluated. Considering diagnostic samples with villous atrophy (VA), the agreement was satisfactory (κ = 0.84), but much less when assessing the severity of these lesions. The use of the recently proposed Corazza‐Villanacci classification showed a moderately higher level of agreement (κ = 0.39) than using the Marsh‐Oberhuber system (κ = 0.31). 57.1% of cases were considered correctly oriented. A number of >4 samples per patient was statistically associated to a better agreement; orientation did not impact on κ values. Agreement results in this study appear more satisfactory than in previous papers and this is justified by the involvement of centers with experience in CD diagnosis and by the well‐controlled setting. Despite this, the reproducibility was far from optimal with a poor agreement in grading the severity of VA. Our results stress the need of a minimum of four samples to be assessed by the pathologist.  相似文献   
139.
Microevolution due to pollution can occur mainly through genetic drift bottlenecks, especially of small sized populations facing intense lethal pulses of contaminants, through mutations, increasing allelic diversity, and through natural selection, with the disappearance of the most sensitive genotypes. This loss of genotypes can lead to serious effects if coupled to specific hypothetical scenarios. These may be categorized as leading, first, to the loss of alleles—the recessive tolerance inheritance hypothesis. Second, leading to a reduction of the population growth rate—the mutational load and fitness costs hypotheses. Third, leading to an increased susceptibility of further genetic erosion both at future inputs of the same contaminant—differential physiological recovery, endpoints (dis)association, and differential phenotypic plasticity hypotheses—and at sequential or simultaneous inputs of other contaminants—the multiple stressors differential tolerance hypothesis. Species in narrowly fluctuating environments (tropics and deep sea) may have a particularly high susceptibility to genetic erosion—the Plus ça change (plus c’est la meme chose) hypothesis. A discussion on the consequences of these hypotheses is what this essay aimed at.  相似文献   
140.

Background/Objectives

A variety of congenital developmental anomalies arise on the neck because of the many fusion planes and complex embryologic structures in this region. We describe a series of seven patients with a novel type of superficial midline congenital anomaly.

Methods

Retrospective case series. Clinical and histopathologic features were compared and used to describe this entity.

Results

Seven patients with nearly identical clinical findings were identified. In all cases, a small superficial cyst resembling a giant milium was observed at birth. There were no significant changes during infancy and no evidence of underlying abnormalities. The histopathologic findings were identical to those of an infundibular follicular cyst.

Conclusion

We have termed this entity midline anterior neck inclusion cyst. We believe it is a superficial developmental anomaly, probably a forme fruste of a midline fusion developmental defect, which has not to our knowledge, previously been described.  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