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   372篇
  免费   20篇
  国内免费   6篇
耳鼻咽喉   1篇
儿科学   5篇
基础医学   37篇
口腔科学   6篇
临床医学   23篇
内科学   44篇
皮肤病学   2篇
神经病学   1篇
特种医学   234篇
外科学   10篇
综合类   2篇
预防医学   4篇
眼科学   3篇
药学   14篇
肿瘤学   12篇
  2021年   2篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2014年   1篇
  2012年   1篇
  2011年   2篇
  2010年   3篇
  2009年   5篇
  2008年   6篇
  2007年   9篇
  2006年   5篇
  2005年   2篇
  2004年   3篇
  2003年   1篇
  2002年   1篇
  2001年   3篇
  2000年   2篇
  1999年   3篇
  1998年   19篇
  1997年   21篇
  1996年   15篇
  1995年   13篇
  1994年   21篇
  1993年   17篇
  1992年   3篇
  1991年   2篇
  1990年   7篇
  1989年   23篇
  1988年   22篇
  1987年   26篇
  1986年   17篇
  1985年   19篇
  1984年   22篇
  1983年   13篇
  1982年   12篇
  1981年   19篇
  1980年   16篇
  1979年   4篇
  1978年   14篇
  1977年   6篇
  1976年   7篇
  1975年   4篇
  1974年   1篇
排序方式: 共有398条查询结果,搜索用时 0 毫秒
11.
12.
Natural killer (NK)-like T cells are major histocompatibility complex- unrestricted cytotoxic T cells that are surface CD3-positive, express NK-cell antigens, and rearrange their T-cell receptor. Most neoplasms arising from this T-cell subpopulation have been a chronic lymphoproliferative disease referred to as T-large granular lymphocyte (LGL) leukemia. Only 10 NK-like T-cell lymphomas have been described in detail previously; this study presents the clinicopathologic features of six others and distinguishes these lymphomas from T-LGL leukemia. All patients presented with B-symptoms and often had marked hepatosplenomegaly without significant peripheral lymphadenopathy. Four of the six patients were immunosuppressed. All had CD3, CD8, CD56- positive tumors, presumably of hepatosplenic (n = 3), intestinal (n = 1), pulmonary (n = 1), or nodal (n = 1) origin. Three patients had lymphomatous bone marrow infiltrates, and four had peripheral blood involvement by neoplastic large lymphocytes, some of which had a blastic appearance or resembled virocytes. Azurophilic granules, ultrastructurally corresponding to cytoplasmic dense core and/or double density granules, were seen in all cases. T-cell clonality was shown in five tumors by Southern blot analysis, and three had abnormal karyotypes. Two untreated patients died 20 days after presentation, and three patients who received combination chemotherapy died within 5 months of presentation. One patient remains in complete remission 22 months after treatment. These findings suggest NK-like T-cell lymphomas are aggressive, are clinicopathologically distinct from T-LGL leukemia, and should be in the differential diagnosis of extranodal T-cell lymphoproliferations, including those in immunosuppressed patients. Furthermore, the LGL morphology, phenotype, and tissue distribution of some NK-like T-cell lymphomas suggest they arise from thymic- independent T cells of the hepatic sinusoids and intestinal mucosa.  相似文献   
13.
Hydrosalpinges adversely affect markers of endometrial receptivity   总被引:22,自引:10,他引:22  
While in-vitro fertilization (IVF) was initially developed in women with tubal factor infertility, recent clinical studies have suggested that the presence of hydrosalpinges lowers implantation and pregnancy rates. We postulated that these hydrosalpinges cause impaired endometrial receptivity. A total of 103 women with hydrosalpinges were prospectively evaluated, and compared with 55 infertile and 44 fertile controls. All women had endometrial biopsies during the window of implantation, analysed by conventional histological criteria, and also stained for three integrin markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha vbeta3). Women with hydrosalpinges (cases) expressed significantly less of the alpha vbeta3 integrin compared with controls. There was no difference in expression of alpha1beta1 or alpha4beta1 among groups. A significantly greater number of cases had out of phase histology and missing alpha vbeta3 (type I defects) and absent integrin expression despite normal histological maturation (type II) defects, compared with controls. Of 20 women with impaired endometrial receptivity who were also biopsied after hydrosalpinx surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven percent of type I and 57% of type II defects were corrected postoperatively. Using markers of endometrial receptivity, this study demonstrates that inflammatory hydrosalpinges have an adverse effect on endometrial receptivity, which in some cases may be overcome by surgical treatment of the hydrosalpinx.   相似文献   
14.
The past 30 years have witnessed a major paradigm shift in brain tumor research with the development of a wide variety of molecular  相似文献   
15.
Magnetic resonance imaging of benign mediastinal masses   总被引:1,自引:0,他引:1  
  相似文献   
16.
Tidwell  T; Guzman  G; Vogler  WR 《Blood》1981,57(4):794-797
The action of an alkyl-lysophospholipid (ALP), ET180CH3, on clonogenicity, 3H-TdR uptake, and cell numbers was tested in two human leukemic cell lines, HL60 and K562, and short-term human leukemic bone marrow cultures. ALP eliminated clonogenicity in HL60 but not in K562 cultures; 3H-TdR uptake and cell numbers were depressed at low concentrations of ET180CH3 in HL60, but not K562 cultures. The action of the lysophospholipid analog on human leukemic bone marrow short-term cultures at low concentrations was similar to its action on HL60 cultures; clonogenicity and 3H-TdR uptake were depressed, but cell numbers were not significantly affected. The demonstration of differential action of ALP on two cell lines should significantly simplify the investigation of the mechanism of the reported differential action of ET180CH3 on normal and leukemic cell membranes.  相似文献   
17.
18.
19.
20.
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