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   119963篇
  免费   44244篇
  国内免费   167篇
耳鼻咽喉   1833篇
儿科学   5249篇
妇产科学   526篇
基础医学   25034篇
口腔科学   6703篇
临床医学   15008篇
内科学   27196篇
皮肤病学   4363篇
神经病学   20808篇
特种医学   6168篇
外科学   15376篇
综合类   1224篇
一般理论   10篇
预防医学   8654篇
眼科学   1410篇
药学   10119篇
  9篇
中国医学   2198篇
肿瘤学   12486篇
  2024年   55篇
  2023年   263篇
  2022年   505篇
  2021年   2207篇
  2020年   6487篇
  2019年   11750篇
  2018年   11279篇
  2017年   12516篇
  2016年   11621篇
  2015年   11535篇
  2014年   11547篇
  2013年   11713篇
  2012年   10789篇
  2011年   10713篇
  2010年   9257篇
  2009年   5782篇
  2008年   6315篇
  2007年   4665篇
  2006年   4470篇
  2005年   4183篇
  2004年   4033篇
  2003年   3679篇
  2002年   3462篇
  2001年   2637篇
  2000年   1452篇
  1999年   326篇
  1998年   87篇
  1997年   99篇
  1996年   73篇
  1995年   75篇
  1994年   78篇
  1993年   68篇
  1992年   54篇
  1991年   69篇
  1990年   75篇
  1989年   50篇
  1988年   40篇
  1987年   32篇
  1986年   33篇
  1985年   45篇
  1984年   46篇
  1983年   25篇
  1982年   33篇
  1981年   22篇
  1980年   31篇
  1979年   19篇
  1978年   18篇
  1977年   25篇
  1976年   9篇
  1974年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
Melatonin receptors play important roles in the regulation of circadian and seasonal rhythms, sleep, retinal functions, the immune system, depression, and type 2 diabetes development. Melatonin receptors are approved drug targets for insomnia, non‐24‐hour sleep‐wake disorders, and major depressive disorders. In mammals, two melatonin receptors (MTRs) exist, MT1 and MT2, belonging to the G protein‐coupled receptor (GPCR) superfamily. Similar to most other GPCRs, reliable antibodies recognizing melatonin receptors proved to be difficult to obtain. Here, we describe the development of the first monoclonal antibodies (mABs) for mouse MT1 and MT2. Purified antibodies were extensively characterized for specific reactivity with mouse, rat, and human MT1 and MT2 by Western blot, immunoprecipitation, immunofluorescence, and proximity ligation assay. Several mABs were specific for either mouse MT1 or MT2. None of the mABs cross‐reacted with rat MTRs, and some were able to react with human MTRs. The specificity of the selected mABs was validated by immunofluorescence microscopy in three established locations (retina, suprachiasmatic nuclei, pituitary gland) for MTR expression in mice using MTR‐KO mice as control. MT2 expression was not detected in mouse insulinoma MIN6 cells or pancreatic beta‐cells. Collectively, we report the first monoclonal antibodies recognizing recombinant and native mouse melatonin receptors that will be valuable tools for future studies.  相似文献   
74.
75.
76.
Deep brain stimulation (DBS) in psychiatric illnesses has been clinically tested over the past 20 years. The clinical application of DBS to the superolateral branch of the medial forebrain bundle in treatment‐resistant depressed patients—one of several targets under investigation—has shown to be promising in a number of uncontrolled open label trials. However, there are remain numerous questions that need to be investigated to understand and optimize the clinical use of DBS in depression, including, for example, the relationship between the symptoms, the biological substrates/projections and the stimulation itself. In the context of precision and customized medicine, the current paper focuses on clinical and experimental research of medial forebrain bundle DBS in depression or in animal models of depression, demonstrating how clinical and scientific progress can work in tandem to test the therapeutic value and investigate the mechanisms of this experimental treatment. As one of the hypotheses is that depression engenders changes in the reward and motivational networks, the review looks at how stimulation of the medial forebrain bundle impacts the dopaminergic system.  相似文献   
77.
Increasing evidence suggests that human epidermal melanocytes play an important role in the skin immune system; however, a role of their pigmentation in immune and inflammatory responses is poorly examined. In the study, the expression of Toll‐like receptor 4 (TLR4) and inflammatory cytokines and chemokines by cultured normal melanocytes derived from lightly and darkly pigmented skin was investigated after cell stimulation with lipopolysaccharide (LPS). The basal TLR4 mRNA level in heavily pigmented cells was higher as compared to their lightly pigmented counterparts. Melanocyte exposure to LPS upregulated the expression of TLR4 mRNA and enhanced the DNA‐binding activity of NF‐κB p50 and p65. We found substantial differences in the LPS‐stimulated expression of numerous genes encoding inflammatory cytokines and chemokines between the cells with various melanin contents. In lightly pigmented melanocytes, the most significantly upregulated genes were nicotinamide phosphoribosyltransferase (NAMPT/visfatin), the chemokines CCL2 and CCL20, and IL6, while the genes for CXCL12, IL‐16 and the chemokine receptor CCR4 were the most significantly upregulated in heavily pigmented cells. Moreover, the lightly pigmented melanocytes secreted much more NAMPT, CCL2 and IL‐6. The results of our study suggest modulatory effect of melanogenesis on the immune properties of normal epidermal melanocytes.  相似文献   
78.
In the “basic” approach, medical expenses are catastrophic if they exceed a prespecified percentage of consumption or income; the approach tells us if expenses cause a large percentage reduction in living standards. The ability‐to‐pay (ATP) approach defines expenses as catastrophic if they exceed a prespecified percentage of consumption less expenses on nonmedical necessities or an allowance for them. The paper argues that the ATP approach does not tell us whether expenses are large enough to undermine a household's ability to purchase nonmedical necessities. The paper compares the income‐based and consumption‐based variants of the basic approach, and shows that if the individual is a borrower after a health shock, the income‐based ratio will exceed the consumption‐based ratio, and both will exceed the more theoretically correct Flores et al. ratio; whereas if the individual continues to be a saver after a health shock, the ordering is reversed and the income‐based ratio may not overestimate Flores et al.'s ratio. Last, the paper proposes a lifetime money metric utility (LMMU) approach defining medical expenses as catastrophic in terms of their lifetime consequences. Under certain assumptions, the LMMU and Flores et al. approaches are identical, and neither requires data on how households finance their medical expenses.  相似文献   
79.
80.
A pulmonary artery (PA) sling is a very rare congenital cardiovascular anomaly, and only a few studies have reported PA slings in fetuses. The relationship of the PA, aorta, ductus arteriosus, and trachea can be evaluated in the 3‐vessel and 3‐vessel and trachea views during fetal echocardiography. A PA sling can be detected by abnormal positioning of the left PA in relation to the trachea when sweeping from the 3‐vessel view cranially to the 3‐vessel and trachea view. Here we report 3 cases of fetal PA slings and their follow‐ups. Two cases were confirmed by postnatal echocardiography, and the other case was confirmed by a cardiovascular cast after pregnancy termination. We emphasize that the 3‐vessel and 3‐vessel and trachea views are of crucial importance in the prenatal diagnosis of a PA sling.  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