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   2617篇
  免费   234篇
  国内免费   79篇
耳鼻咽喉   30篇
儿科学   105篇
妇产科学   40篇
基础医学   311篇
口腔科学   85篇
临床医学   254篇
内科学   561篇
皮肤病学   31篇
神经病学   225篇
特种医学   147篇
外科学   275篇
综合类   188篇
一般理论   3篇
预防医学   160篇
眼科学   53篇
药学   276篇
  3篇
中国医学   10篇
肿瘤学   173篇
  2022年   41篇
  2021年   70篇
  2020年   38篇
  2019年   66篇
  2018年   69篇
  2017年   31篇
  2016年   49篇
  2015年   65篇
  2014年   88篇
  2013年   109篇
  2012年   138篇
  2011年   126篇
  2010年   70篇
  2009年   65篇
  2008年   100篇
  2007年   185篇
  2006年   113篇
  2005年   107篇
  2004年   100篇
  2003年   79篇
  2002年   73篇
  2001年   70篇
  2000年   70篇
  1999年   54篇
  1998年   36篇
  1997年   43篇
  1996年   43篇
  1995年   35篇
  1994年   29篇
  1993年   28篇
  1992年   52篇
  1991年   39篇
  1990年   36篇
  1989年   48篇
  1988年   44篇
  1987年   28篇
  1986年   27篇
  1985年   36篇
  1984年   25篇
  1983年   27篇
  1982年   25篇
  1981年   26篇
  1980年   25篇
  1979年   32篇
  1978年   26篇
  1977年   33篇
  1976年   24篇
  1975年   24篇
  1973年   32篇
  1971年   22篇
排序方式: 共有2930条查询结果,搜索用时 15 毫秒
41.
Homelessness is common among people who use drugs (PWUD) and, for those living with HIV/AIDS, an important contributor to sub-optimal HIV treatment outcomes. This study aims to investigate the relationship between the duration of homelessness and the likelihood of plasma HIV-1 RNA viral load (VL) non-detectability among a cohort of HIV-positive PWUD. We used data from the ACCESS study, a long-running prospective cohort study of HIV-positive PWUD linked to comprehensive HIV clinical records including systematic plasma HIV-1 RNA VL monitoring. We estimated the longitudinal relationship between the duration of homelessness and the likelihood of exhibiting a non-detectable VL (i.e., <500?copies/mL plasma) using generalized linear mixed-effects modelling. Between May 1996 and June 2014, 922 highly active antiretroviral therapy-exposed participants were recruited and contributed 8188 observations. Of these, 4800 (59%) were characterized by non-detectable VL. Participants reported they were homeless in 910 (11%) interviews (median: six months, interquartile range: 6–12 months). A longer duration of homelessness was associated with lower odds of VL non-detectability (adjusted odds ratio?=?0.71 per six-month period of homelessness, 95% confidence interval: 0.60–0.83) after adjustment for age, ancestry, drug use patterns, engagement in addiction treatment, and other potential confounders. Longer durations of episodes of homelessness in this cohort of HIV-positive illicit drug users were associated with a lower likelihood of plasma VL non-detectability. Our findings suggest that interventions that seek to promptly house homeless individuals, such as Housing First approaches, might assist in maximizing the clinical and public health benefits of antiretroviral therapy among people living with HIV/AIDS.  相似文献   
42.
43.
Autologous free-fat grafting (AFG) has emerged as an attractive proposition for soft-tissue reconstruction of various contour defects because it obviates more complex reconstructive options and reduces operative times and donor-site morbidity. Nonetheless, a common complication of this procedure is the resorption of the engrafted fat. Cell-assisted lipotransfer (CAL) is now a well-regarded technique where adipose-derived stem cell (ASC)-rich stromal vascular fraction is admixed with lipoaspirate, increasing the volumetric outcome of fat grafts in light of its potent angiogenic and adipogenic properties. Criticisms, however, remain regarding this modality especially for the treatment of post-oncologic defects. Laboratory data has attested to its propensity to perpetuate tumor cells as a result of its paracrine effects on the host microenvironment. This review article aims to present the underlying facts behind ASC therapy and provide meaningful discourse as to its utility in post-oncologic soft tissue reconstruction.  相似文献   
44.
45.
46.
Bacterial lipopolysaccharides (LPS) are structural components of the outer membranes of Gram-negative bacteria and also are potent inducers of inflammation in mammals. Higher vertebrates are extremely sensitive to LPS, but lower vertebrates, like fish, are resistant to their systemic toxic effects. However, the effects of LPS on the fish intestinal mucosa remain unknown. Edwardsiella ictaluri is a primitive member of the Enterobacteriaceae family that causes enteric septicemia in channel catfish (Ictalurus punctatus). E. ictaluri infects and colonizes deep lymphoid tissues upon oral or immersion infection. Both gut and olfactory organs are the primary sites of invasion. At the systemic level, E. ictaluri pathogenesis is relatively well characterized, but our knowledge about E. ictaluri intestinal interaction is limited. Recently, we observed that E. ictaluri oligo-polysaccharide (O-PS) LPS mutants have differential effects on the intestinal epithelia of orally inoculated catfish. Here we evaluate the effects of E. ictaluri O-PS LPS mutants by using a novel catfish intestinal loop model and compare it to the rabbit ileal loop model inoculated with Salmonella enterica serovar Typhimurium LPS. We found evident differences in rabbit ileal loop and catfish ileal loop responses to E. ictaluri and S. Typhimurium LPS. We determined that catfish respond to E. ictaluri LPS but not to S. Typhimurium LPS. We also determined that E. ictaluri inhibits cytokine production and induces disruption of the intestinal fish epithelia in an O-PS-dependent fashion. The E. ictaluri wild type and ΔwibT LPS mutant caused intestinal tissue damage and inhibited proinflammatory cytokine synthesis, in contrast to E. ictaluri Δgne and Δugd LPS mutants. We concluded that the E. ictaluri O-PS subunits play a major role during pathogenesis, since they influence the recognition of the LPS by the intestinal mucosal immune system of the catfish. The LPS structure of E. ictaluri mutants is needed to understand the mechanism of interaction.  相似文献   
47.
Sixteen polymorphic, dinucleotide microsatellite loci were developed for Rhoadsia altipinna, a small characid fish from impacted rivers in south western Ecuador. None of the loci were in linkage disequilibrium or deviated significantly from Hardy–Weinberg equilibrium after sequential Bonferroni correction. Variability was relatively high with allelic richness ranging between 2 and 22 alleles per locus (average = 9.125), observed heterozygosity ranging between 0.125 and 0.958 (average = 0.695), and expected heterozygosity ranging between 0.120 and 0.952 (average = 0.736).  相似文献   
48.
49.
50.
Left ventricular (LV) thrombus is commonly seen in patients with extensive anterior ST-elevation myocardial infarction. The standard of care for LV thrombus is anticoagulation with warfarin. However, there has been an increasing trend of case reports using non-vitamin K antagonist oral anticoagulants (NOAC) for the treatment of LV thrombus. This study aimed to perform a meta-summary of the literature to characterise and evaluate the safety and feasibility of using NOAC in patients with LV thrombus. We searched for articles published in four electronic databases: PubMed, EMBASE, Scopus and Google Scholar using an appropriate keyword/MeSH term search strategy. Twenty-four studies comprising 36 patients were included in the analysis. Rivaroxaban was used in majority of patients (47.2%), whilst Apixaban and Dabigatran were prescribed in 25.0% and 27.8% of patients respectively. The most commonly associated risk factor found was post-acute myocardial infarction in 15 patients (41.7%). LV thrombus resolution was met by most patients (87.9%), and the median duration of treatment to resolution was 30.0 days (IQR?=?22.5–47.0). One non-fatal bleeding event (3.0%) and no embolic events were reported. The use of NOAC may have a role in the treatment of LV thrombus in selected patients. Further randomized controlled trials are needed to evaluate this treatment strategy.  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