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   159035篇
  免费   50030篇
  国内免费   3555篇
耳鼻咽喉   2382篇
儿科学   5929篇
妇产科学   2982篇
基础医学   25098篇
口腔科学   6410篇
临床医学   22589篇
内科学   36554篇
皮肤病学   8800篇
神经病学   17732篇
特种医学   5449篇
外国民族医学   13篇
外科学   23038篇
综合类   10167篇
现状与发展   13篇
一般理论   36篇
预防医学   10079篇
眼科学   3221篇
药学   13778篇
  60篇
中国医学   4444篇
肿瘤学   13846篇
  2024年   135篇
  2023年   817篇
  2022年   1884篇
  2021年   4429篇
  2020年   7075篇
  2019年   12631篇
  2018年   12412篇
  2017年   13294篇
  2016年   13877篇
  2015年   14850篇
  2014年   15743篇
  2013年   16608篇
  2012年   10912篇
  2011年   10882篇
  2010年   13272篇
  2009年   9159篇
  2008年   7114篇
  2007年   6061篇
  2006年   5851篇
  2005年   5084篇
  2004年   4483篇
  2003年   4360篇
  2002年   3866篇
  2001年   3304篇
  2000年   2825篇
  1999年   2002篇
  1998年   815篇
  1997年   704篇
  1996年   587篇
  1995年   512篇
  1994年   479篇
  1993年   308篇
  1992年   797篇
  1991年   631篇
  1990年   569篇
  1989年   530篇
  1988年   447篇
  1987年   450篇
  1986年   376篇
  1985年   317篇
  1984年   241篇
  1983年   198篇
  1982年   122篇
  1981年   138篇
  1980年   106篇
  1979年   213篇
  1978年   167篇
  1977年   105篇
  1976年   113篇
  1975年   110篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
91.
92.
93.
Tuberculosis (TB) remains one of a major health problem worldwide. Tuberculosis vaccine research has made an extraordinary progress over the past few years. However, there is still no replacement for the Bacillus Calmette‐Guérin vaccine, the only TB vaccine licensed for human use. Therefore, the discovery and development of new TB vaccines remains a priority. This article discusses current strategies used to diversify TB vaccines and includes discussion of the status of efforts to improve protection against Mycobacterium tuberculosis (M tb) infection or TB disease by developing new and safe TB vaccines. This article also highlights the current research efforts in immune‐enhancing approaches to improve vaccination efficacy. The development of more effective TB vaccines might have significant impact on global TB control.  相似文献   
94.
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   
95.
96.
97.
98.
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   
99.
目的 检测微小核糖核酸(microribonucleicacids,miRNA)在老年性黄斑变性(age-related macular degeneration,AMD)患者中的表达,并探讨miRNA的表达量与AMD病程之间的关系。方法 选取2014年1月至2016年11月于同济大学附属第十人民医院眼科门诊就诊的AMD患者6例为试验组,并选取同期6名正常人为对照组,通过基因芯片技术检测两组血液中miRNA的表达量。扩大样本的病例对照研究中共纳入126例AMD患者和140名正常人,检测其血液样本中miRNA的表达,比较两组人群间miRNA的表达量差异。结果 通过基因芯片技术,在试验组与对照组间共检测出216个miRNA存在表达差异(均为P<0.05),与对照组相比,试验组中111个miRNA表达量上升,105个miRNA表达量下降,差异均有统计学意义(均为P<0.05)。扩大样本的病例对照研究结果表明,在AMD患者中,miR-27a-3p、miR-29b-3p、miR-195-5p的表达量显著上升,同时,湿性AMD患者血液中miR-27a-3p的表达量高于干性AMD患者,差异均有统计学意义(均为P<0.05)。结论 AMD患者外周血中miRNA表达量水平有明显变化,miR-27a-3p、miR-29b-3p、miR-195-5p可能成为AMD血清学诊断和预后的标志物。  相似文献   
100.
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