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   144054篇
  免费   5680篇
  国内免费   10924篇
耳鼻咽喉   1164篇
儿科学   2251篇
妇产科学   2409篇
基础医学   17463篇
口腔科学   1769篇
临床医学   8828篇
内科学   23974篇
皮肤病学   1236篇
神经病学   7676篇
特种医学   7073篇
外国民族医学   268篇
外科学   13498篇
综合类   29478篇
现状与发展   145篇
一般理论   39篇
预防医学   9458篇
眼科学   5903篇
药学   12163篇
  26篇
中国医学   3281篇
肿瘤学   12556篇
  2024年   149篇
  2023年   533篇
  2022年   673篇
  2021年   715篇
  2020年   493篇
  2019年   884篇
  2018年   1021篇
  2017年   489篇
  2016年   625篇
  2015年   864篇
  2014年   2318篇
  2013年   1138篇
  2012年   18305篇
  2011年   20042篇
  2010年   3869篇
  2009年   2116篇
  2008年   11923篇
  2007年   12457篇
  2006年   16436篇
  2005年   16225篇
  2004年   8989篇
  2003年   8558篇
  2002年   6512篇
  2001年   4613篇
  2000年   4807篇
  1999年   2627篇
  1998年   1212篇
  1997年   687篇
  1996年   443篇
  1995年   684篇
  1994年   442篇
  1993年   474篇
  1992年   398篇
  1991年   439篇
  1990年   386篇
  1989年   793篇
  1988年   648篇
  1987年   730篇
  1986年   539篇
  1985年   662篇
  1984年   628篇
  1983年   547篇
  1982年   448篇
  1981年   379篇
  1980年   282篇
  1979年   156篇
  1959年   171篇
  1958年   249篇
  1957年   240篇
  1955年   164篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
1.
Stroke is the second leading cause of death and a major cause of disability worldwide, and biological sex is an important determining factor in stroke incidence and pathology. From childhood through adulthood, men have a higher incidence of stroke compared with women. Abundant research has confirmed the beneficial effects of estrogen in experimental ischemic stroke but genetic factors such as the X-chromosome complement can also play an important role in determining sex differences in stroke. Au...  相似文献   
2.
<正>Glial cells play a key role during nervous system development and actively participate in all the cellular processes involved in maintaining its structural robustness and functional plasticity.In response to neuronal damage,glial cells proliferate,migrate to the injured region and change their morphology,function,and behavior  相似文献   
3.
Dear Editor,Conjunctival cyst of the orbit acquired from enucleation is an infrequent but serious complication;which can occur in 3%-7%of patients,more commonly after a secondary procedure;.The most common manifestations are the inability to retain the external prosthesis.  相似文献   
4.
Neuroinflammation and the NACHT, LRR, and PYD domains-containing protein 3 inflammasome play crucial roles in secondary tissue damage following an initial insult in patients with traumatic brain injury(TBI). Maraviroc, a C-C chemokine receptor type 5 antagonist, has been viewed as a new therapeutic strategy for many neuroinflammatory diseases. We studied the effect of maraviroc on TBI-induced neuroinflammation. A moderate-TBI mouse model was subjected to a controlled cortical impact device. Mara...  相似文献   
5.
<正>Skin is the first line of defense against a wide variety of physical and chemical damages.Photodamage of the skin can have an effect on beauty, while it is correlated with various skin diseases. Accordingly, effective prevention of skin photodamage has constantly been a research hotspot in the field of skin.The precursor protein of amyloid β-protein (APP)refers to a type of transmembrane protein that has been widely found in numerous types of cells.  相似文献   
6.
目的 分析南京市某国际高中学生艾滋病知识知晓率及其影响因素,为制定高中生艾滋病健康教育策略提供依据。方法 对南京市某国际高中所有学生开展纸质问卷调查,统计分析艾滋病知识知晓率及其影响因素。 共纳入171名高中生为调查对象,艾滋病和梅毒的知识知晓率分别为56.1%和46.8%;有过性行为的占14.6%,其艾滋病知识知晓率最高为32.0%,(χ2=10.799,P=0.005);有吸毒史的学生占9.3%,其艾滋病知识知晓率最高为31.2%,(χ2=21.062,P<0.001);梅毒知识知晓者与不知晓者的艾滋病知识知晓率差异具有统计学意义(χ2=21.716,P<0.001)。 该国际高中学生性病和艾滋病知识知晓率较低,对高中生开展毒品危害教育和性病艾滋病防治应作为健康教育工作重点。  相似文献   
7.
8.
Gangliosides, sialic acid-containing sphingolipids, are major constituents of neuronal membranes. According to the number of sialic acids and the structure of the oligosaccharide chain, gangliosides can be classified as simple or complex and grouped in different ganglio-series. Hundreds of gangliosides have been identified in vertebrate cells, with different expression patterns during development and related to several physiological processes, especially in the nervous system. While GD3 and its ...  相似文献   
9.
BACKGROUND Esophageal squamous cell carcinoma(ESCC)is one of the most prevalent malignancies that seriously threaten people’s health worldwide.DEAD-box helicase 51(DDX51)is a member of the DEAD-box(DDX)RNA helicase family,and drives or inhibits tumor progression in multiple cancer types.AIM To determine whether DDX51 affects the biological behavior of ESCC.METHODS The expression of DDX51 in ESCC tumor tissues and adjacent normal tissues was detected by Immunohistochemistry(IHC)analyses and quantitative PCR(qPCR).We knocked down DDX51 in ESCC cell lines by using a small interfering RNA(siRNA)transfection.The proliferation,apoptosis,and mobility of DDX51 siRNAtransfected cells were detected.The effect of DDX51 on the phosphoinositide 3-kinase(PI3K)/AKT pathway was investigated by western blot analysis.A mouse xenograft model was established to investigate the effects of DDX51 knockdown on ESCC tumor growth.RESULTS DDX51 exhibited high expression in ESCC tissues compared with normal tissues and represented a poor prognosis in patients with ESCC.Knockdown of DDX51 induced inhibition of ESCC cell proliferation and promoted apoptosis.Moreover,DDX51 siRNA-expressing cells also exhibited lower migration and invasion rates.Investigations into the underlying mechanisms suggested that DDX51 knock down induced inactivation of the PI3K/AKT pathway,including decreased phosphorylation levels of phosphate and tensin homolog,PI3K,AKT,and mammalian target of rapamycin.Rescue experiments demonstrated that the AKT activator insulin-like growth factor 1 could reverse the inhibitory effects of DDX51 on ESCC malignant development.Finally,we injected DDX51 siRNA-transfected TE-1 cells into an animal model,which resulted in slower tumor growth.CONCLUSION Our study suggests for the first time that DDX51 promotes cancer cell proliferation by regulating the PI3K/AKT pathway;thus,DDX51 might be a therapeutic target for ESCC.  相似文献   
10.
Zedoary tumeric (Curcumae Rhizoma, Ezhu in Chinese) has a long history of application and has great potential in the treatment of liver cancer. The anti liver cancer effect of zedoary tumeric depends on the combined action of multiple pharmacodynamic substances. In order to clarify the specific mechanism of zedoary tumeric against liver cancer, this paper first analyzes the mechanism of its single pharmacodynamic substance against liver cancer, and then verifies the joint anti liver cancer mechanism of its "pharmacodynamic group". By searching the research on the anti hepatoma effect of active components of zedoary tumeric in recent years, we found that pharmacodynamic substances, including curcumol, zedoarondiol, curcumenol, curzerenone, curdione, curcumin, germacrone, β-elemene, can act on multi-target and multi-channel to play an anti hepatoma role. For example, curcumin can regulate miR, GLO1, CD133, VEGF, YAP, LIN28B, GPR81, HCAR-1, P53 and PI3K/Akt/mTOR, HSP70/TLR4 and NF-κB. Wnt/TGF/EMT, Nrf2/Keap1, JAK/STAT and other pathways play an anti hepatoma role. Network pharmacological analysis showed that the core targets of the "pharmacodynamic group" for anti-life cancer are AKT1, EGFR, MAPK8, etc, and the core pathways are neuroactive live receiver interaction, nitrogen metabolism, HIF-1 signaling pathway, etc. At the same time, by comparing and analyzing the relationship between the specific mechanisms of pharmacodynamic substance and "pharmacodynamic group", it is found that they have great reference significance in target, pathway, biological function, determination of core pharmacodynamic components, formation of core target protein interaction, in-depth research of single pharmacodynamic substance, increasing curative effect and so on. By analyzing the internal mechanism of zedoary tumeric pharmacodynamic substance and "pharmacodynamic group" in the treatment of liver cancer, this paper intends to provide some ideas and references for the deeper pharmacological research of zedoary tumeric and the relationship between pharmacodynamic substance and "pharmacodynamic group".  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