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   1267篇
  免费   82篇
  国内免费   8篇
耳鼻咽喉   17篇
儿科学   61篇
妇产科学   25篇
基础医学   135篇
口腔科学   26篇
临床医学   111篇
内科学   201篇
皮肤病学   20篇
神经病学   127篇
特种医学   131篇
外科学   247篇
综合类   16篇
一般理论   1篇
预防医学   93篇
眼科学   17篇
药学   62篇
肿瘤学   67篇
  2023年   8篇
  2022年   7篇
  2021年   14篇
  2020年   9篇
  2019年   20篇
  2018年   28篇
  2017年   25篇
  2016年   28篇
  2015年   24篇
  2014年   37篇
  2013年   52篇
  2012年   92篇
  2011年   80篇
  2010年   74篇
  2009年   62篇
  2008年   62篇
  2007年   64篇
  2006年   58篇
  2005年   58篇
  2004年   41篇
  2003年   40篇
  2002年   29篇
  2001年   29篇
  2000年   29篇
  1999年   31篇
  1998年   29篇
  1997年   22篇
  1996年   25篇
  1995年   23篇
  1994年   13篇
  1993年   11篇
  1992年   19篇
  1991年   15篇
  1990年   20篇
  1989年   21篇
  1988年   20篇
  1987年   22篇
  1986年   17篇
  1985年   7篇
  1984年   7篇
  1982年   4篇
  1981年   5篇
  1980年   5篇
  1979年   5篇
  1977年   10篇
  1976年   6篇
  1972年   8篇
  1970年   4篇
  1968年   4篇
  1965年   6篇
排序方式: 共有1357条查询结果,搜索用时 15 毫秒
51.

Objective

Metabolic syndrome (MetSyn) is a well-known risk factor for cardiovascular (CV) disease in the general population; however, the additional predictive value for CV events in high-risk patients with peripheral arterial disease (PAD) is unknown. The aims of the current study were to assess and compare: (1) prevalence of MetSyn, and (2) predictive value of MetSyn for CV events, in patients with either occlusive or aneurysmatic PAD.

Methods

We screened 2069 patients scheduled for lower occlusive arterial revascularization (n = 1031) or abdominal aortic aneurysm repair (n = 1038) for the presence of MetSyn. Adult Treatment Panel III report (ATP III) was used for defining MetSyn. Central obesity was defined as body-mass-index >30 kg/m2. Main outcomes were the occurrence of CV events and CV mortality during a median follow-up of 6 years (IQR 2–9 years).

Results

Metabolic syndrome was diagnosed in 421 (41%) and 432 (42%) patients with occlusive and aneurysmatic PAD, respectively (p = 0.72). Patients with occlusive or aneurysmatic PAD and MetSyn had an increased risk for the development of CV events, when compared to patients without MetSyn (27% vs. 18% and 27% vs. 19%, p < 0.001, respectively). In occlusive and aneurysmatic PAD, MetSyn was independently associated with an increased risk of CV events (HR = 1.6; 95%CI 1.2–2.1 and HR = 1.4; 95%CI 1.1–1.8). No significant association between the presence of MetSyn and CV mortality was observed.

Conclusions

Metabolic syndrome is highly prevalent in high-risk PAD patients. In occlusive and aneurysmatic PAD patients, MetSyn is an independent predictor of long-term CV events.  相似文献   
52.
BACKGROUND: To review the accuracy of multivariate models for the predictionof ovarian reserve and pregnancy in women undergoing IVF comparedwith the antral follicle count (AFC) as single test. METHODS: We performed a computerized MEDLINE and EMBASE search to identifyarticles published on multivariate models for ovarian reservetesting in patients undergoing IVF. In order to be selected,articles had to contain data on the outcome of IVF in termsof either pregnancy and/or poor response and on the predictionof these events based on a multivariate model. For the selectedstudies, sensitivity and specificity of the test in the predictionof poor ovarian response and non-pregnancy were calculated.Overall performance was assessed by estimating a summary receiveroperating characteristic (ROC) curve, which was compared withthe ROC curve for the AFC as the current best single test. RESULTS: We identified 11 studies reporting on the predictive capacityof multivariate models in ovarian reserve testing. All studiesreported on the prediction of poor ovarian response, whereasnone reported on the occurrence of pregnancy. The sensitivityfor prediction of poor ovarian response varied between 39% and97% and the specificity between 50% and 96%. Logistic regressionanalysis indicated that cohort studies provided a significantlybetter discriminative performance than case–control studies.As cohort studies are superior to case–control studies,further analysis was limited to the cohort studies. For thecohort studies, a summary ROC curve could be estimated, whichhad a shape similar to that previously made for the AFC. CONCLUSIONS: The accuracy of multivariate models for the prediction of ovarianresponse in women undergoing IVF is similar to the accuracyof AFC. No data are available on the capacity of these modelsto predict pregnancy, let alone live birth. On the basis ofthese findings, the use of more than one single test for theassessment of ovarian reserve cannot currently be supported.  相似文献   
53.
The Loeys–Dietz syndrome (LDS) is a connective tissue disorder affecting the cardiovascular, skeletal, and ocular system. Most typically, LDS patients present with aortic aneurysms and arterial tortuosity, hypertelorism, and bifid/broad uvula or cleft palate. Initially, mutations in transforming growth factor‐β (TGF‐β) receptors (TGFBR1 and TGFBR2) were described to cause LDS, hereby leading to impaired TGF‐β signaling. More recently, TGF‐β ligands, TGFB2 and TGFB3, as well as intracellular downstream effectors of the TGF‐β pathway, SMAD2 and SMAD3, were shown to be involved in LDS. This emphasizes the role of disturbed TGF‐β signaling in LDS pathogenesis. Since most literature so far has focused on TGFBR1/2, we provide a comprehensive review on the known and some novel TGFB2/3 and SMAD2/3 mutations. For TGFB2 and SMAD3, the clinical manifestations, both of the patients previously described in the literature and our newly reported patients, are summarized in detail. This clearly indicates that LDS concerns a disorder with a broad phenotypical spectrum that is still emerging as more patients will be identified. All mutations described here are present in the corresponding Leiden Open Variant Database.  相似文献   
54.
Does anal HPV viral load explain the difference in anal HPV persistence between HIV‐negative and ‐positive men who have sex with men (MSM)? MSM ≥18 years were recruited in Amsterdam, the Netherlands, in 2010‐2011. Anal self‐swabs were collected every 6 months and genotyped (SPF10‐PCR‐DEIA‐LIPA25‐system). HPV16 and HPV18 load was determined with a type specific quantitative (q)PCR, and compared between HIV‐negative and ‐positive men using ranksum test. Persistence was defined as ≥3 positive samples for the same HPV‐type. Determinants of persistent HPV16/18 infection and its association with HPV16/18 load were assessed with logistic regression. Of 777 recruited MSM, 54 and 22 HIV negative men were HPV16 and HPV18 positive at baseline, and 64 and 39 HIV‐positive MSM. The geometric mean titer (GMT) of HPV16 was 19.6 (95%CI 10.1‐38.0) and of HPV18 8.6 (95%CI 2.7‐27.5) DNA copies/human cell. HPV16 and HPV18 load did not differ significantly between HIV‐negative and ‐positive MSM (P = 0.7; P = 0.8, respectively). In multivariable analyses HPV16 load was an independent determinant of HPV16 persistence (OR 1.8, 95%CI 1.3‐2.4). No difference in anal HPV viral load was found between HIV‐positive and HIV‐negative MSM. HPV 16/18 viral load is an independent determinant of type‐specific persistence.  相似文献   
55.
We describe a reliable noninvasive fetal human platelet antigen (HPA)-1a genotyping assay on a real-time polymerase chain reaction (PCR) platform using cell-free fetal DNA isolated from maternal blood. Nonspecific amplification of maternal cell-free DNA is overcome by pre-PCR digestion of the cell-free DNA with the Msp1 restriction enzyme. Noninvasive fetal HPA-1a genotyping offers a safe method for alloimmunised pregnant women to determine whether their fetus is at risk of fetal or neonatal alloimmune thrombocytopenia (FNAIT) and whether interventions to prevent intracranial haemorrhage are required. The availability of this test is relevant to the ongoing debate on screening pregnancies for HPA-1a-mediated FNAIT.  相似文献   
56.
57.
58.
Background: In this report we describe, for the first time, the activation of the peripheral immune compartment in a patient with a CRB1 linked retinal degenerative disease, masquerading as intermediate uveitis.

Methods: To monitor the immune system during systemic immunosuppressive treatment, given for the initial diagnosis of intermediate uveitis, blood samples were taken before and during therapy, for analysis of peripheral blood mononuclear cell-subsets and circulating immune mediators.

Results: The levels of various pro-inflammatory immune mediators (including MIF, TSLP, CCL2/MCP-1, CXCL9, CXCL10, IFN-β, IL-6, IL-17, IL-21, IL-22, and IL-23) were elevated in serum at the first time point, and decreased under immunosuppressive treatment. In parallel, the frequency of activated (CD86+) CD1c+ myeloid dendritic cells in blood was proportional to the central foveal thickness measured by optical coherence tomography.

Conclusions: These observations challenge the current view on the distinct pathophysiology of retinal degenerative and retinal inflammatory conditions in this patient.  相似文献   

59.

Background  

Childhood obesity is a substantial public health problem. The extent to which health state preferences (utilities) are related to a child's weight status has not been reported. The aims of this study were (1) to use a generic health state classification system to measure health related quality of life and calculate health utilities in a convenience sample of children and adolescents and (2) to determine the extent to which these measures are associated with weight status and body mass index (BMI).  相似文献   
60.
Genital asymmetry in men   总被引:1,自引:0,他引:1  
This study examined genital asymmetry in a large sample of men. The probands were 6544 non-delinquent men who were interviewed by the Kinsey Institute for Research in Sex, Gender and Reproduction from 1938 to 1963. The measures were four indicators of penile and scrotal asymmetry, along with self-reported handedness, from Kinsey's interview protocol. Most men reported some degree of lateral asymmetry in their flaccid penis and in their testicles; less asymmetry was reported for their erect penis. The asymmetry typically occurred in the left direction, and this pattern occurred in both right- and nonright- handers. However, this 'leftward' pattern was significantly less pronounced in nonright-handers. The results are discussed in relation to previous findings of genital asymmetry in men, the possible relationship of genital asymmetry to functional cerebral asymmetry, and recent data suggesting genital asymmetry may predict patterns of cognitive performance and genital/sexual organ cancers.   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