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   8548篇
  免费   602篇
  国内免费   116篇
耳鼻咽喉   64篇
儿科学   225篇
妇产科学   396篇
基础医学   945篇
口腔科学   188篇
临床医学   1042篇
内科学   1734篇
皮肤病学   77篇
神经病学   713篇
特种医学   330篇
外科学   1099篇
综合类   240篇
一般理论   4篇
预防医学   479篇
眼科学   180篇
药学   729篇
中国医学   84篇
肿瘤学   737篇
  2023年   45篇
  2022年   108篇
  2021年   179篇
  2020年   106篇
  2019年   177篇
  2018年   215篇
  2017年   175篇
  2016年   175篇
  2015年   245篇
  2014年   284篇
  2013年   379篇
  2012年   547篇
  2011年   620篇
  2010年   412篇
  2009年   351篇
  2008年   505篇
  2007年   513篇
  2006年   530篇
  2005年   465篇
  2004年   399篇
  2003年   331篇
  2002年   299篇
  2001年   273篇
  2000年   230篇
  1999年   200篇
  1998年   90篇
  1997年   82篇
  1996年   77篇
  1995年   57篇
  1994年   50篇
  1993年   49篇
  1992年   115篇
  1991年   118篇
  1990年   101篇
  1989年   82篇
  1988年   80篇
  1987年   81篇
  1986年   48篇
  1985年   43篇
  1984年   37篇
  1983年   37篇
  1982年   28篇
  1981年   27篇
  1980年   21篇
  1979年   28篇
  1978年   33篇
  1976年   20篇
  1975年   18篇
  1974年   26篇
  1968年   18篇
排序方式: 共有9266条查询结果,搜索用时 31 毫秒
131.
132.
Nobiletin, a bioactive polymethoxylated flavone (5,6,7,8,3',4'‐hexamethoxyflavone), is abundant in citrus fruit peel. Although nobiletin exhibits antitumor activity against various cancer cells, the effect of nobiletin on glioma cells remains unclear. The aim of this study was to determine the effects of nobiletin on the human U87 and Hs683 glioma cell lines. Treating glioma cells with nobiletin (20–100 µm ) reduced cell viability and arrested the cell cycle in the G0/G1 phase, as detected using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and propidium iodide (PI) staining, respectively; however, nobiletin did not induce cell apoptosis according to PI‐annexin V double staining. Data from western blotting showed that nobiletin significantly attenuated the expression of cyclin D1, cyclin‐dependent kinase 2, cyclin‐dependent kinase 4, and E2 promoter‐binding factor 1 (E2F1) and the phosphorylation of Akt/protein kinase B and mitogen‐activated protein kinases, including p38, extracellular signal‐regulated kinase, and c‐Jun N‐terminal kinase. Our data also showed that nobiletin inhibited glioma cell migration, as detected by both functional wound healing and transwell migration assays. Altogether, the present results suggest that nobiletin inhibits mitogen‐activated protein kinase and Akt/protein kinase B pathways and downregulates positive regulators of the cell cycle, leading to subsequent suppression of glioma cell proliferation and migration. Our findings evidence that nobiletin may have potential for treating glioblastoma multiforme. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
133.
Over the last decade, the use of portable ultrasound scanners has enhanced the concept of point of care ultrasound (PoC-US), namely, “ultrasound performed at the bedside and interpreted directly by the treating clinician.” PoC-US is not a replacement for comprehensive ultrasound, but rather allows physicians immediate access to clinical imaging for rapid and direct solutions. PoC-US has already revolutionized everyday clinical practice, and it is believed that it will dramatically change how ultrasound is applied in daily practice. However, its use and teaching are different from continent to continent and from country to country. This World Federation for Ultrasound in Medicine and Biology position paper discusses the current status and future perspectives of PoC-US. Particular attention is given to the different uses of PoC-US and its clinical significance, including within emergency and critical care medicine, cardiology, anesthesiology, rheumatology, obstetrics, neonatology, gynecology, gastroenterology and many other applications. In the future, PoC-US will be more diverse than ever and be included in medical student training.  相似文献   
134.
Melatonin (N‐acetyl‐5‐methoxytryptamine)/MT2 receptor‐dependent epigenetic modification represents a novel pathway in the treatment of neuropathic pain. Because spinal ten‐eleven translocation methylcytosine dioxygenase 1 (Tet1)‐dependent epigenetic demethylation has recently been linked to pain hypersensitivity, we hypothesized that melatonin/MT2‐dependent analgesia involves spinal Tet1‐dependent demethylation. Here, we showed that spinal Tet1 gene transfer by intrathecal delivery of Tet1‐encoding vectors to naïve rats produced profound and long‐lasting nociceptive hypersensitivity. In addition, enhanced Tet1 expression, Tet1‐metabotropic glutamate receptor subtype 5 (mGluR5) promoter coupling, demethylation at the mGluR5 promoter, and mGluR5 expression in dorsal horn neurons were observed. Rats subjected to spinal nerve ligation and intraplantar complete Freund's adjuvant injection displayed tactile allodynia and behavioral hyperalgesia associated with similar changes in the dorsal horn. Notably, intrathecal melatonin injection reversed the protein expression, protein‐promoter coupling, promoter demethylation, and pain hypersensitivity induced by Tet1 gene transfer, spinal nerve ligation, and intraplantar complete Freund's adjuvant injection. All the effects caused by melatonin were blocked by pretreatment with a MT2 receptor‐selective antagonist. In conclusion, melatonin relieves pain by impeding Tet1‐dependent demethylation of mGluR5 in dorsal horn neurons through the MT2 receptor. Our findings link melatonin/MT2 signaling to Tet1‐dependent epigenetic demethylation of nociceptive genes for the first time and suggest melatonin as a promising therapy for the treatment of pain.  相似文献   
135.
136.
Mutations affecting recombination activation genes RAG1 and RAG2 are associated with variable phenotypes, depending on the residual recombinase activity. The aim of this study is to describe a variety of clinical phenotypes in RAG-deficient patients from the highly consanguineous Egyptian population. Thirty-one patients with RAG mutations (from 28 families) were included from 2013 to 2017. On the basis of clinical, immunological and genetic data, patients were subdivided into three groups; classical TB severe combined immunodeficiency (SCID), Omenn syndrome (OS) and atypical SCID. Nineteen patients presented with typical TBSCID; among these, five patients carried a homozygous RAG2 mutation G35V and five others carried two homozygous RAG2 mutations (T215I and R229Q) that were detected together. Four novel mutations were reported in the TBSCID group; three in RAG1 (A565P, N591Pfs*14 and K621E) and one in RAG2 (F29S). Seven patients presented with OS and a novel RAG2 mutation (C419W) was documented in one patient. The atypical SCID group comprised five patients. Two had normal B cell counts; one had a previously undescribed RAG2 mutation (V327D). The other three patients presented with autoimmune cytopaenias and features of combined immunodeficiency and were diagnosed at a relatively late age and with a substantial diagnostic delay; one patient had a novel RAG1 mutation (C335R). PID disorders are frequent among Egyptian children because of the high consanguinity. RAG mutations stand behind several variable phenotypes, including classical SCID, OS, atypical SCID with autoimmunity and TB+ CID.  相似文献   
137.
Currently, tumor necrosis factor alpha (TNF-alpha) inhibitors are widely used for many autoimmune disorders. However, they cause an immunocompromised status that sometimes leads to many cutaneous side effects including atypical infections. Herein, we report the first case of adalimumab-related Majocchi''s granuloma.A 43-year-old Taiwanese male patient with chronic plaque-type psoriasis developed numerous tender nodules 1 month after adalimumab injection. The nodules responded poorly to bacterial folliculitis treatment. After repeated skin biopsies for pathology and tissue fungal culture, Majocchi''s granuloma was confirmed. Adalimumab was withheld, and 12 weeks of terbinafine treatment was given. On completion of treatment, the nodular skin lesions and dystrophic nail lesions improved dramatically.The information, including time span, clinical features, histological findings, and improvement following withdrawal of adalimumab and treatment with an oral antifungal agent, indicates that Majocchi''s granuloma was adalimumab-related. Psoriasis patients are more susceptible to dermatophyte infection due to local and systemic immunosuppressant therapy. It is important to perform a thorough examination for latent dermatophyte infection, including skin and nail lesions, before treatment with TNF-alpha inhibitors and during traditional psoriasis treatment. When atypical presentation together with treatment failure is noted in psoriasis patients prescribed biologics, clinicians should investigate evidence of dermatophyte infection and provide proper treatment. Sometimes, multiple skin biopsies and tissue fungal cultures are required to establish a correct diagnosis.  相似文献   
138.
139.
140.
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