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   43033篇
  免费   2299篇
  国内免费   135篇
耳鼻咽喉   642篇
儿科学   1791篇
妇产科学   725篇
基础医学   5753篇
口腔科学   1185篇
临床医学   2777篇
内科学   10621篇
皮肤病学   1427篇
神经病学   3484篇
特种医学   1230篇
外科学   5767篇
综合类   269篇
一般理论   17篇
预防医学   3775篇
眼科学   1169篇
药学   2527篇
中国医学   212篇
肿瘤学   2096篇
  2024年   30篇
  2023年   296篇
  2022年   264篇
  2021年   1107篇
  2020年   525篇
  2019年   1224篇
  2018年   1919篇
  2017年   1123篇
  2016年   929篇
  2015年   817篇
  2014年   1000篇
  2013年   1750篇
  2012年   3120篇
  2011年   3560篇
  2010年   1704篇
  2009年   1060篇
  2008年   2773篇
  2007年   2869篇
  2006年   2594篇
  2005年   2664篇
  2004年   2450篇
  2003年   2390篇
  2002年   2132篇
  2001年   1502篇
  2000年   1972篇
  1999年   1020篇
  1998年   332篇
  1997年   231篇
  1996年   217篇
  1995年   180篇
  1994年   159篇
  1993年   147篇
  1992年   143篇
  1991年   112篇
  1990年   101篇
  1989年   111篇
  1988年   107篇
  1987年   76篇
  1986年   66篇
  1985年   79篇
  1984年   81篇
  1983年   58篇
  1982年   53篇
  1981年   37篇
  1980年   47篇
  1979年   29篇
  1978年   41篇
  1977年   44篇
  1976年   35篇
  1975年   39篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
851.
852.
853.
854.
Background  Epidemiological studies have associated androgenetic alopecia (AGA) with severe young-age coronary artery disease and hypertension, and linked it to insulin resistance. We carried out a case–control study in age- and weight-matched young males to study the link between AGA and insulin resistance using the homeostasis model assessment of insulin resistance (HOMA-IR) index or metabolic syndrome clinical manifestations.
Methods  Eighty young males, 18–35 years old, with AGA ≥ stage III in the Hamilton–Norwood classification, and 80 weight- and age-matched controls were included. Alopecia, glucose, serum insulin, HOMA-IR index, lipid profile and androgen levels, as well as metabolic syndrome criteria, were evaluated.
Results  The HOMA-IR index was significantly higher in cases than controls. Nonobese cases had a higher mean diastolic blood pressure and a more frequent family history of AGA than nonobese controls. A borderline difference in the HOMA-IR index was found in obese AGA cases vs. obese controls [ P =  0·055, 95% confidence interval (CI) 2·36–4·20 vs. 1·75–2·73]. Free testosterone values were significantly higher in controls than cases, regardless of body mass index (BMI). A statistically significant additive effect for obesity plus alopecia was found, with significant trends for insulin, the HOMA-IR index, lipids and free testosterone when BMI and alopecia status were used to classify the participants.
Conclusions  Our results support the recommendation for assessing insulin resistance and cardiovascular-related features and disorders in all young males with stage III or higher AGA, according to the Hamilton–Norwood classification.  相似文献   
855.
856.
OBJECTIVE: To examine the accumulation of risk factors over 3 years in a multicenter, international inception cohort of patients with systemic lupus erythematosus (SLE). METHODS: The Systemic Lupus International Collaborating Clinics registry for atherosclerosis comprises 27 centers from 11 countries. An inception cohort of 935 patients with SLE was assembled, according to a standardized protocol, from 2000 to 2006 to study risk factors for atherosclerosis. Both classic and other coronary artery disease (CAD) risk factors were collected at entry and through 3 years of followup. Therapy was documented over the 3 years. The Framingham 10-year risk factor profile was calculated for each patient at year 1 and year 3. RESULTS: A total of 278 patients from the inception cohort were followed for 3 years and constituted the population for this study. At enrollment a substantial number of patients already demonstrated several risk factors for CAD, both classic and other. All risk factors increased from enrollment over the 3 years of followup. Treatment of hypertension and hypercholesterolemia also increased over 3 years, but less so for hypercholesterolemia. The Framingham 10-year CAD risk profile was higher in men than in women both at entry and at 3 years, and remained unchanged over the 3 years. Corticosteroid use increased only slightly over 3 years, but use of antimalarials and immunosuppressive agents increased to a greater extent. CONCLUSION: Patients with SLE should be monitored for CAD risk factors from the time of diagnosis and appropriate treatment should be instituted early.  相似文献   
857.
PURPOSE OF REVIEW: Respiratory syncytial virus is the leading viral pathogen associated with lower respiratory tract infection in young children worldwide. The pathogenesis of acute bronchiolitis and the mechanisms by which the virus induces long-term airway disease remain to be elucidated. This review highlights new findings reported in the English-language medical literature from January 2004 to January 2005. RECENT FINDINGS: Several studies have confirmed a strong association between respiratory syncytial virus infection in infancy and an increased risk for recurrent wheezing. Evidence indicates that the exaggerated immune response and abnormal neurogenic mechanisms induced by the virus play a significant role in the pathogenesis of the disease. Different genetic and immune markers have been correlated with acute disease severity and with increased risk of long-term pulmonary abnormalities. Recently, the application of real time polymerase chain reaction has demonstrated the persistence of respiratory syncytial virus RNA in the lungs of infected mice for months after inoculation. This unexpected observation has stimulated discussions as to whether the long-term presence of the virus could contribute to the long-term airway disease observed in children after respiratory syncytial virus lower respiratory tract infection. SUMMARY: Despite almost half a century of active research into the pathogenesis of respiratory syncytial virus-induced acute and chronic airway disease, many questions remain unresolved. Studies in animal models demonstrate that interventions reducing viral replication resulted in improvement of acute disease severity and long-term pulmonary abnormalities. The stage is ready for clinical studies to determine whether preventing or delaying the primary infection could reduce the incidence of recurrent wheezing in children.  相似文献   
858.
ABSTRACT

Identifying the genetic and non-genetic determinants of obesity and related cardiometabolic dysfunctions is cornerstone for their prevention, treatment, and control. While genetic variants contribute to the cardiometabolic syndrome (CMS), non-genetic factors, such as the gut microbiota, also play key roles. Gut microbiota is intimately associated with CMS and its composition is heritable. However, associations between this microbial community and host genetics are understudied. We contribute filling this gap by genotyping 60 variants in 39 genes of three modules involved in CMS risk, measuring cardiometabolic risk factors, and characterizing gut microbiota in a cohort of 441 Colombians. We hypothesized that CMS risk variants were correlated with detrimental levels of clinical parameters and with the abundance of disease-associated microbes. We found several polymorphisms in genes of innate immunity, appetite control, and energy metabolism that were associated with metabolic dysregulation and microbiota composition; the associations between host genetics and cardiometabolic health were independent of the participants’ gut microbiota, and those between polymorphisms and gut microbes were independent of the CMS risk. Associations were also independent of the host genetic ancestry, diet and lifestyle. Most microbes explaining genetic-microbiota associations belonged to the families Lachnospiraceae and Ruminococcaceae. Multiple CMS risk alleles were correlated with increased abundance of beneficial microbiota, suggesting that the phenotypic outcome of the evaluated variants might depend upon the genetic background of the studied population and its environmental context. Our results provide additional evidence that the gut microbiota is under the host genetic control and present pathways of host–microbe interactions.  相似文献   
859.
A sentinel chicken program for West Nile virus (WNV) surveillance was initiated in July 2006 in eastern Puerto Rico, yielding the first seroconversions on June 4, 2007. WNV was isolated from sentinel chicken serum and mosquito pools (Culex nigripalpus, Culex bahamensis) for the first time in Tropical America. Preliminary sequence analysis of the prM and E genes revealed a 1-amino acid difference (V159A) between the Puerto Rican 2007 and the NY99. This mutation has been observed in the current dominant clade circulating in the United States. Sentinel chicken surveillance was a useful tool for the detection of West Nile virus in the tropics.  相似文献   
860.
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