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   528篇
  免费   19篇
  国内免费   16篇
儿科学   39篇
妇产科学   6篇
基础医学   44篇
口腔科学   9篇
临床医学   71篇
内科学   93篇
皮肤病学   5篇
神经病学   20篇
特种医学   102篇
外科学   70篇
综合类   39篇
预防医学   21篇
眼科学   4篇
药学   29篇
中国医学   1篇
肿瘤学   10篇
  2021年   4篇
  2019年   4篇
  2018年   4篇
  2017年   4篇
  2016年   4篇
  2015年   8篇
  2014年   12篇
  2013年   17篇
  2012年   18篇
  2011年   14篇
  2010年   25篇
  2009年   18篇
  2008年   11篇
  2007年   15篇
  2006年   13篇
  2005年   9篇
  2003年   8篇
  2002年   8篇
  2001年   10篇
  2000年   11篇
  1999年   22篇
  1998年   25篇
  1997年   27篇
  1996年   27篇
  1995年   20篇
  1994年   18篇
  1993年   15篇
  1991年   5篇
  1990年   8篇
  1989年   21篇
  1988年   19篇
  1987年   13篇
  1986年   15篇
  1985年   9篇
  1984年   5篇
  1983年   10篇
  1982年   3篇
  1981年   7篇
  1980年   10篇
  1979年   3篇
  1978年   4篇
  1977年   5篇
  1976年   4篇
  1975年   6篇
  1973年   5篇
  1972年   3篇
  1971年   3篇
  1970年   4篇
  1967年   4篇
  1966年   4篇
排序方式: 共有563条查询结果,搜索用时 15 毫秒
41.
42.
43.
Pagetoid squamous cell carcinoma in situ (PSSCIS) is a variant of squamous cell intraepithelial neoplasia. Although PSSCIS is well-documented in the cutaneous skin and esophagus, cases of vulvar PSSCIS are rare. In the vulva, the main differential diagnosis is extramammary Paget disease (EMPD). We report 2 cases of vulvar PSSCIS along with the immunohistochemical and human papillomavirus (HPV) status of this disease compared with primary cutaneous EMPD of the vulva. Although PSSCIS and EMPD share CK7 and CK19 expression, PSSCIS is consistently mucin and carcinoembryonic antigen negative. In contrast to EMPD, both cases of PSSCIS strongly expressed p16 (INK4A) protein, consistent with RB1 protein dysregulation. However, integration of high-risk HPV was found in only 1 of the 2 PSSCIS cases. Given the morphological and immunohistochemical findings, we suggest that PSSCIS arises from a bidirectional stem cell capable of both squamous and glandular differentiation. Additionally, as with nonpagetoid squamous cell neoplasias of the vulvar, integration of high-risk HPV may occur in some, but not all, cases of PSSCIS.  相似文献   
44.
KJ Kao 《Transfusion》1988,28(1):14-17
To determine whether chloroquine can specifically elute HLA antigens and beta 2-microglobulin (beta 2-M) from the platelet surface, quantitative immunofluorescence flow cytometry and monoclonal antibodies were used to show that HLA antigens and beta 2-M were proportionally eluted from the platelet surface without affecting the membrane glycoproteins IIb and IIIa. Second, an autoradiogram of electrophoresed I125-labeled platelets showed that only beta 2-M but not other I125-labeled membrane proteins could be eluted. Although HLA antigens were poorly labeled by I125 and could not be detected on the autoradiogram, the eluted HLA antigens could be detected by anti-HLA monoclonal antibody and immunoblotting techniques. No loss of plasma membrane integrity was observed by transmission electron microscopy after chloroquine treatment of platelets. The results indicate that chloroquine selectively elutes HLA antigens and their noncovalently associated beta 2-M without affecting other integral platelet membrane proteins.  相似文献   
45.
目的:观察低血糖指数的膳食对2型糖尿病患者氧化应激状态的影响。方法:2004-10/11在上海市静安区二个社区卫生服务中心招募受试者,经医生明确诊断为2型糖尿病、病程超过6个月,体质量指数≥24kg/m2的老年糖尿病志愿者43名,受试者对试验知情同意。采用随机交叉试验随机分配至低血糖指数饮食组和高血糖指数饮食组,每种膳食分别连续使用4周,间隔洗脱期4周,比较试验前后患者超氧化物歧化酶、脂质过氧化产物丙二醛和谷胱甘肽过氧化物酶含量的变化。结果:受试者依从性好,除1人因试验期间发现肿瘤而退出试验,42名志愿者按设计要求完成试验。膳食干预后低血糖指数饮食组和高血糖指数饮食组的超氧化物歧化酶活力分别升高了15.68%和21.33%,丙二醛水平分别下降23.94%和21.55%,谷胱甘肽过氧化物酶活力分别升高了15.74%和17.09%;干预后低血糖指数饮食组丙二醛下降水平与高血糖指数饮食组比较差异有显著性意义(P<0.05),而超氧化物歧化酶和谷胱甘肽过氧化物酶活性两组间差异无显著性意义(P>0.05)。结论:在控制总能量的基础上给予平衡膳食能够改善其氧化应激水平,采用低血糖指数食物有助于氧化应激水平的改善。  相似文献   
46.

Background  

Selective serotonin reuptake inhibitors (SSRIs), a popular class of antidepressants, may increase breast cancer risk by stimulating the secretion of prolactin, a potential tumour promoter. We evaluated the effects of duration of SSRI use, cumulative dose, and latency on the risk of breast cancer by conducting a population-based case-control study utilizing Saskatchewan health databases.  相似文献   
47.
48.
Between September 1970 and May 1971 six cases of human infection with monkeypox virus were identified in three West African countries—Liberia, Sierra Leone, and Nigeria. Four of the cases were confirmed by viral isolation, and two were diagnosed on epidemiological and serological evidence. Poxvirus strains isolated from the four cases were indistinguishable from reference monkeypox strains (Copenhagen and Utrecht), and all were easily differentiated from variola and vaccinia viruses. The isolated strains produced small necrotic haemorrhagic pocks on CAM, grew well at 39.0°C, formed large plaques in Vero cell cultures, showed markedly more virulence for chick embryos and mice than do variola strains, and produced large necrotic haemorrhagic local lesions with generalized illness and florid secondary exanthem when inoculated into rabbit skin.  相似文献   
49.
Sonoelasticity imaging of prostate cancer: in vitro results   总被引:2,自引:0,他引:2  
  相似文献   
50.
To understand the hematopoietic and nonhematopoietic responses to interleukin-3 (IL-3), expression of cell-surface IL-3 receptors (IL-3R) was examined on bone marrow (BM) cells and peripheral blood (PB) cells of rhesus monkeys during the course of in vivo IL-3 treatment. Whereas IL-3R expression is low in untreated monkeys, IL-3 administration led to a gradual increase in both low- and high-affinity binding sites for IL-3. This increase reflected the total number of cells expressing IL- 3Rs, as detected by flow cytometry using biotinylated IL-3. Most of these IL-3R+ cells in both BM and PB could be characterized as basophilic granulocytes that contained high levels of histamine. In contrast to the effect on these differentiated cells, IL-3 administration did not significantly alter the low level IL-3R expression on immature, CD34+ cells. Further flow cytometric analysis using biotinylated growth factors showed that the IL-3R+ basophils also expressed receptors for granulocyte-macrophage colony-stimulating factor (GM-CSF), but not for IL-6 or Kit ligand. These findings indicated that the IL-3R+ cells included neither monocytes, which express GM-CSFRs and IL-6Rs abundantly, nor mast cells, which express c- kit. By combining flow cytometric and Scatchard data, it was calculated that the basophils contain as many as 1 to 2 x 10(3) high-affinity IL- 3Rs and 15 to 30 x 10(3) low-affinity sites. The finding that in vivo IL-3 treatment leads to the production of large numbers of cells that express high levels of IL-3R and are capable of producing histamine provides an explanation for the often severe allergic reactions that occur during prolonged IL-3 administration. It also indicates that IL- 3, in addition to its direct effects on hematopoietic cells, may also stimulate hematopoiesis through the release of secondary mediators such as histamine by IL-3-responsive mature cells.  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