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   234篇
  免费   23篇
儿科学   10篇
妇产科学   3篇
基础医学   29篇
口腔科学   4篇
临床医学   24篇
内科学   37篇
皮肤病学   1篇
神经病学   20篇
特种医学   4篇
外科学   70篇
综合类   5篇
预防医学   26篇
眼科学   1篇
药学   15篇
肿瘤学   8篇
  2024年   1篇
  2023年   1篇
  2021年   2篇
  2020年   4篇
  2019年   10篇
  2018年   7篇
  2017年   4篇
  2016年   14篇
  2015年   8篇
  2014年   16篇
  2013年   10篇
  2012年   17篇
  2011年   18篇
  2010年   10篇
  2009年   8篇
  2008年   11篇
  2007年   11篇
  2006年   9篇
  2005年   13篇
  2004年   10篇
  2003年   12篇
  2002年   6篇
  2001年   9篇
  2000年   4篇
  1999年   4篇
  1997年   1篇
  1996年   1篇
  1994年   1篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   2篇
  1986年   2篇
  1985年   9篇
  1984年   4篇
  1983年   2篇
  1980年   1篇
  1978年   1篇
  1977年   2篇
排序方式: 共有257条查询结果,搜索用时 0 毫秒
1.
Patients with chronic kidney disease (CKD), ranging from modest renal impairment to dialysis and transplant, have an increased risk for cardiovascular disease (CVD). Patients with CKD have both traditional and non-traditional risk factors for CVD. The role of lipids as risk factors for CVD in these populations has not been firmly established. In a recent prospective controlled trial, it was established that atherogenic lipids are indeed strong risk factors for CVD in renal transplant recipients, and that treatment with a HMG-CoA reductase inhibitor reduced the incidence of cardiac death and myocardial infarction. For patients receiving dialysis, the association between serum lipid levels and cardiovascular outcome is uncertain and there is no evidence from controlled trials that lipid-lowering therapy does have a beneficial effect on cardiovascular outcome in these patients. Atherogenic lipids are probably a risk factor for patients with mild or moderate CKD, and five subgroup analyses have indicated a favorable effect of lipid-lowering therapy on cardiovascular outcome, although we still lack prospective controlled trials in these patients. CVD in patients with CKD has been a neglected area of research.  相似文献   
2.
Individual sarcocysts were isolated from fresh or alcohol-fixed muscle samples of two moose from Alberta, Canada, and examined by light (LM) and scanning electron microscopy (SEM) and molecular methods, comprising polymerase chain reaction (PCR) amplification and sequencing of the complete18S rRNA gene and the partial cytochrome c oxidase subunit I gene (cox1). By LM, four sarcocyst types were recognized, and the sequencing results showed that each type represented a distinct species, i.e. Sarcocystis alces, Sarcocystis alceslatrans, Sarcocystis ovalis and Sarcocystis taeniata n. sp. The finding of S. alceslatrans and S. ovalis has been reported briefly previously, but further details are provided here, including the ultrastructure of sarcoysts of S. alceslatrans as seen by SEM. The species S. alces was found for the first time in Canadian moose, whereas the finding of S. taeniata is the first record of this species in any host. The sarcocysts of S. taeniata were sac-like and about 1,000–1,100?×?60–80 μm in size. By LM, the cysts had a thin and smooth wall with no visible protrusions, whereas SEM revealed that the cyst surface had sparsely but regularly distributed, thin ribbon-like protrusions, about 2 μm long and 0.2 μm wide, lying flat against the surface and leaving most of the cyst surface naked. Similar protrusions have previously been reported from Sarcocystis grueneri in reindeer, which was found by sequence comparisons and phylogenetic analyses to be the species most closely related to S. taeniata. The phylogenetic analyses further suggested that S. taeniata, like S. alces and S. alceslatrans, use canids as definitive hosts, whereas corvid birds are known definitive hosts for S. ovalis. In contrast to the three other species found, S. taeniata displayed considerable intra-specific and intra-isolate sequence variation (substitutions, insertions/deletions) in certain regions of the 18S rRNA gene.  相似文献   
3.
The arctic fox (Vulpes lagopus) is a critically endangered species in Norway, and therefore, the small population is closely monitored, and most foxes found dead are subjected to necropsy. In two deceased foxes, thin-walled muscular sarcocysts were first detected in histological sections, and numerous sarcocysts were later found in frozen and thawed muscle samples from Fox 1. These sarcocysts measured 1–12?×?0.1–0.25 mm and had closely spaced, short, knob-like protrusions, giving the cysts a serrated outline. Genomic DNA was extracted from eight isolated sarcocysts (Fox 1) and two muscle samples (Fox 2) and subjected to polymerase chain reaction amplification at four loci: the nuclear 18S and 28S ribosomal RNA genes and internal transcribed spacer 1 region and the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Both foxes were infected by the same Sarcocystis sp., which displayed little or no genetic variation at the three nuclear loci (99.9–100 % identity) and slightly more variation at cox1 (99.4–100 % identity). Sequence comparisons and phylogenetic analyses revealed that this species was distinct from other named Sarcocystis spp. but was closely related to various species using avian intermediate hosts and possibly identical to an unnamed species reported from two American dogs. The species described from the two arctic foxes was named Sarcocystis arctica n. sp.  相似文献   
4.
Background:Adipose tissue is critical for systemic metabolic health. Identifying key factors regulating adipose tissue function is a research priority. The NR4A subfamily of nuclear receptors (NRs) (NR4A1/NUR77, NR4A2/NURR1 and NR4A3/NOR1) has emerged as important proteins in different disease states and in the regulation of metabolic tissues, particularly in liver and muscle. However, the expression of the NR4A members in human adipose tissue has not previously been described, and their target genes are largely unknown.Objective:To determine whether the NR4As are differentially expressed in human adipose tissue in obesity, and identify potential NR4A target genes.Design:Prospective analysis of s.c. adipose tissue before and 1 year after fat loss, and during in vitro differentiation of primary human preadipocytes. Case-control comparison of omental (OM) adipose tissue.Subjects:A total of 13 extremely obese patients undergoing biliopancreatic diversion with duodenal switch for fat loss, 12 extremely obese patients undergoing laparoscopic sleeve gastrectomy and 37 lean individuals undergoing hernia repair or laparotomy were included in the study. Measurements were done by quantitative PCR gene expression analysis of the NR4A members and in silico promoter analysis based on microarray data.Results:There was a strong upregulation of the NR4As in extreme obesity and normalization after fat loss. The NR4As were expressed at the highest level in stromal-vascular fraction compared with adipocytes, but were downregulated in both fractions after fat loss. Their expression levels were also significantly higher in OM compared with s.c. adipocytes in obesity. The NR4As were downregulated during differentiation of primary human preadipocytes. Moreover, the NR4As were strongly induced within 30?min of tissue incubation. Finally, promoter analysis revealed potential NR4A target genes involved in stress response, immune response, development and other functions. Our data show altered adipose tissue expression of the NR4As in obesity, suggesting that these stress responsive nuclear receptors may modulate pathogenic potential in humans.  相似文献   
5.

Introduction and hypothesis

The aim of this study was to gain in-depth knowledge of women suffering from urinary incontinence (UI) in rural and semiurban settings in Ethiopia.

Methods

A qualitative study based on semistructured in-depth interviews with 26 informants, 18 of whom were women experiencing the symptom of urinary leakage. The study was conducted in the Amhara Region of northwest Ethiopia and was part of the Dabat Incontinence and Prolapse (DABINCOP) study.

Results

Limited access to water, soap, pads, and spare clothes characterized daily management of the symptom. The consequences for marital relationships and social life were of great concern to the informants. Shame, embarrassment, and fear of being discriminated against led to huge efforts to hide the leakage. Among informants who were not able to hide it, humiliating comments and discriminatory behavior were commonly experienced, sometimes leading to divorce and self-isolation. Women who disclosed their symptom usually had a person who supported them. Women with UI regarded it as unnatural and uncommon. Most took no action to improve the situation, as they saw no options for help.

Conclusions

Several circumstances limited the opportunities available to women to keep themselves clean, disclose the problem to others, and access health information and health-care facilities. In order to understand how women in this setting practically handled, perceived, and experienced living with UI, it was essential to address contextualized and sociocultural dimensions related to the symptom.  相似文献   
6.
7.
Although separate prediction models for donors and recipients were previously published, we identified a need to predict outcomes of donor/recipient simultaneously, as they are clearly not independent of each other. We used characteristics from transplantations performed at the Oslo University Hospital from 1854 live donors and from 837 recipients of a live donor kidney transplant to derive Cox models for predicting donor mortality up to 20 years, and recipient death, and graft loss up to 10 years. The models were developed using the multivariable fractional polynomials algorithm optimizing Akaike’s information criterion, and optimism-corrected performance was assessed. Age, year of donation, smoking status, cholesterol and creatinine were selected to predict donor mortality (C-statistic of 0.81). Linear predictors for donor mortality served as summary of donor prognosis in recipient models. Age, sex, year of transplantation, dialysis vintage, primary renal disease, cerebrovascular disease, peripheral vascular disease and HLA mismatch were selected to predict recipient mortality (C-statistic of 0.77). Age, dialysis vintage, linear predictor of donor mortality, HLA mismatch, peripheral vascular disease and heart disease were selected to predict graft loss (C-statistic of 0.66). Our prediction models inform decision-making at the time of transplant counselling and are implemented as online calculators.  相似文献   
8.

Purpose

To determine whether personality disorders (PDs) are associated with increased risk of disability pensioning in young adults, independent of other common mental disorders.

Methods

2,770 young adults from the general population were assessed for PDs by the Structured Interview for DSM-IV Personality, and for common mental disorders by the Composite of International Diagnostic Interview. These data were linked to the Norwegian National Insurance Administration’s recordings of disability benefits for a 10-year period. Logistic regression analyses were applied to investigate the association between PDs and disability pensioning. The analyses were conducted for three types of PD measures: categorical diagnoses (any PD), dimensional scores of individual PDs and higher order components retrieved by principal component analyses.

Results

Having any PD was strongly associated with disability pensioning, regardless of disability diagnosis. The estimated odds ratio (OR) was substantially higher for PDs [OR 4.69 (95 % confidence interval (CI) 2.6–8.5)] than for mood disorders [OR 1.3 (CI 0.7–2.3)] and anxiety disorders [OR 2.3 (CI 1.3–4.3)]. Measured dimensionally, all PD traits except antisocial traits were significantly associated with disability pensioning. After adjusting for co-occurring traits of other PDs, only schizoid, dependent and borderline PD traits showed a significant positive association with disability pension, while antisocial traits showed a significant negative association. The principal component analyses showed that negative affectivity, psychoticism, and detachment was associated with an increased risk of disability pensioning, while antagonism/disinhibition and obsessivity were not.

Conclusions

PDs are strongly associated with disability pensioning in young adults, and might be more important predictors of work disability than anxiety and depressive disorders. Certain aspects of pathologic personalities are particularly important predictors of disability.  相似文献   
9.
Stool samples containing Giardia duodenalis cysts were collected from 95 primary-school children in central Cuba, and preserved by storing at -20 degrees C in 70% ethanol. Clinical data were collected for each child. Although 57% of the children were asymptomatic, the remaining 43% each reported between one and three symptoms. Following cyst quantification and isolation, molecular analyses were attempted on all cyst isolates, with the focus on the parasite's beta-giardin and glutamate-dehydrogenase (gdh) genes. Unfortunately, the cyst-preservation procedure appeared to have a deleterious effect on the cysts, since genotyping data could only be obtained for 20 of the 95 isolates. These data indicated, however, an approximately equal distribution between assemblage A (nine isolates) and assemblage B (11 isolates). Children found to be excreting relatively large numbers of cysts were more likely to be symptomatic than children who were excreting fewer cysts, and children with Giardia isolates from assemblage B were more likely to have symptomatic infections than children with isolates from assemblage A. Although considerable sequence variability was seen in the assemblage-B isolates, the assemblage-A isolates were relatively genetically homogeneous. This is the first publication from the Caribbean in which the Giardia genotypes circulating within the population have been identified, the first from the Americas providing information on associations between clinical presentation and the assemblage of the infecting Giardia, and the first to indicate that levels of cyst excretion may have clinical significance.  相似文献   
10.
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