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   667篇
  免费   67篇
  国内免费   9篇
耳鼻咽喉   1篇
儿科学   39篇
妇产科学   12篇
基础医学   55篇
口腔科学   21篇
临床医学   122篇
内科学   162篇
皮肤病学   40篇
神经病学   19篇
特种医学   101篇
外科学   77篇
综合类   12篇
预防医学   22篇
眼科学   3篇
药学   12篇
肿瘤学   45篇
  2023年   8篇
  2021年   6篇
  2020年   5篇
  2019年   8篇
  2018年   15篇
  2017年   15篇
  2016年   24篇
  2015年   19篇
  2014年   31篇
  2013年   29篇
  2012年   15篇
  2011年   20篇
  2010年   31篇
  2009年   53篇
  2008年   19篇
  2007年   14篇
  2006年   24篇
  2005年   18篇
  2004年   16篇
  2003年   16篇
  2002年   8篇
  2001年   9篇
  2000年   6篇
  1999年   12篇
  1998年   34篇
  1997年   34篇
  1996年   36篇
  1995年   26篇
  1994年   24篇
  1993年   29篇
  1992年   7篇
  1991年   6篇
  1990年   7篇
  1989年   15篇
  1988年   12篇
  1987年   19篇
  1986年   11篇
  1985年   9篇
  1984年   8篇
  1983年   5篇
  1982年   3篇
  1981年   9篇
  1980年   5篇
  1978年   3篇
  1977年   3篇
  1976年   5篇
  1975年   2篇
  1974年   2篇
  1965年   1篇
  1963年   2篇
排序方式: 共有743条查询结果,搜索用时 15 毫秒
101.
Background: Recent studies have demonstrated the usefulness of gene-modified tumor cells for immunotherapy. Using the tumorigenic murine fibrosarcoma, MCA 106, we investigated the effects of localized interferon-γ (IFNg) secretion on tumorigenicity and on long-term memory. Methods: The murine IFNg (MuIFNg) gene was introduced into tumor cells. High and low IFNg-secreting clones were isolated. C57BL/6 mice were injected subcutaneously (s.c.) with either parental (P), high or low IFNg-secreting (H- or L-IFNg) cells, and tumor growth was assessed weekly. Spleens were harvested on different days postinjection (p.i.) to assess in vitro cytolytic activity. In parallel, tissues from injection sites were stained with macrophage-, CD4-, and CD8-detecting antibodies. Mice were injected s.c. with H-IFNg MCA106 tumor. After 150 days the animals were rechallenged s.c. with MCA106P in one leg and with irrelevant syngeneic tumor in the other. Results: Both P- and L-IFNg cells had similar growth, whereas the H-IFNg cells never grew. Only splenocytes from the H-IFNg animals showed in vitro CTL activity persisting until day 30 p.i. Histological data revealed a macrophage and CD4+ infiltrate much earlier in the H-IFNg group compared with the P group. Only the irrelevant, syngeneic tumor grew in animals previously injected with H-IFNg cells, whereas both P and irrelevant syngeneic tumors grew in controls. Conclusions: Transduction of MCA106 cells with the MuIFNg gene diminished in vivo tumorigenicity in proportion to the amount of IFNg secreted. Immunization with H-IFNg cells elicited a host response characterized by macrophages and CD4+ cells. Long-term tumor-specific memory was seen after immunization with H-IFNg cells.  相似文献   
102.
103.
104.
Abstract: Several clinicopathologic variables influence prognosis in breast cancer, including stage, histologic grade, nodal status, and tumor size. Multiple studies have shown an independent value of proliferation index as a prognostic variable for the stratification into favorable and unfavorable groups. The monoclonal antibody MIB-1 reacts with the same antigen site, not epitope, as recognized by the Ki-67 antibody. Like Ki-67, MIB-1 reacts with cells in the late G1, S, M and G2 phases of the cell cycle, but MIB-1 has the advantage of reacting with formalin-fixed, paraffin-embedded material. The authors investigated the feasibility of using image analysis to quantitate the MIB-1 antibody staining (proliferation index [PI]) and predict survival in a series of 230 patients with stage I and stage II breast cancer. In a univariate Cox regression model, larger values of MIB-1 were related to shorter survival times (p < 0.001). Exploratory statistical procedures were used to categorize the patients into good, intermediate, and poor survival groups using the following proliferation indices as cut-points: <5%, 5–11%, and >11 %, respectively. Higher clinical stage was associated with higher MIB-1 values and shorter survival (p = 0.01, and p = 0.003, respectively). Tumor size (p = 0.02) and nodal status (p = 0.05) were also associated with higher values of MIB-1. After adjusting for age, clinical stage, nodal status, and tumor size in a multivariate analysis, MIB-1 retained its prognostic significance (p < 0.0001) when considered as either a continuous or categorical variable. There were no significant associations between MIB-1 determined proliferation index and age (p = 0.54), histologic grade (p = 0.69), nuclear grade (p = 0.06) or the presence of vascular invasion (p =.66). There is a strong statistical relationship between cell proliferative activity, as determined by MIB-1 expression, and survival in early stage breast cancer.  相似文献   
105.
106.
Grossman  LB; Buonocore  E; Modic  MT; Meaney  TF 《Radiology》1984,150(2):323-325
Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram.  相似文献   
107.
IMMUNOLOGICAL FEATURES OF HLA-B27 ANTERIOR UVEITIS   总被引:2,自引:0,他引:2  
Analysis ol the immunological features of anterior Uveitis (AU) revealed a dichotomy of abnormalities defined in terms of the HLA-B27 status of the patient. HLA-B27-positive AU was characterised by the occurrence of ins autoantibodies and an absolute T cell lymphopenia during active disease which returned to normal with recovery. This phenomenon was not observed in HLA-B27-negative AU or in controls and could not be attributed to antilymphocyte antibodies as these were not detected. Furthermore, there were no changes in T-cell subsets (helper and suppressor T lymphocytes). Compared with HLA-B27-positive AU patients, the HLA-B27-negative group demonstrated elevated lgE levels and increased prevalence of smooth muscle autoantibodies. Key words: anterior Uveitis, HLA-B27, immunological abnormalities, T lymphocytes, autoantibodies.  相似文献   
108.
109.
Gray-scale ultrasonography of the normal female pelvis   总被引:5,自引:0,他引:5  
Sample  WF; Lippe  BM; Gyepes  MT 《Radiology》1977,125(2):477
  相似文献   
110.
The purpose of this study was to analyze the effects of 2 days/week versus 4 days/week of Whole Body Vibration (WBV) during eight weeks of WBV training on health-related quality of life (SF-36), balance and lower body strength, as well as short-term detraining (3 weeks) on balance and lower body strength among older adults. Thirty-four older adults were randomly assigned to a control group (Control; n = 11) or to one of the vibration training groups: WBV 2 days/week (WBV_2d; n = 11) or WBV 4 days/week (WBV_4d; n = 12). The WBV groups exercised for 8 weeks, following 3 weeks of detraining. Lower body strength increased significantly (p < 0.05) for both groups, WBV_2d and WBV_4d, after 8-week training. A significant reduction in strength was observed following 3 weeks of detraining only in WBV_2d group (p < 0.05). All variables of the SF-36 and the balance test did not change after intervention in any group. 2 days/week and 4 days/week of WBV during 8 weeks showed the same improvements on muscle strength. 3 weeks of detraining did not reverse the gains in strength made during 32 sessions of WBV.

Key points

  • 2 days and 4 days per week of WBV training during 8 weeks showed the same improvements on muscle strength.
  • 3 weeks of detraining did not reverse the gains in strength made during 32 sessions of WBV exercise.
  • 3 weeks of detraining did reverse the gains in strength made during 16 sessions of WBV exercise.
Key words: Whole-body vibrations, posturography, dose-response, equilibrium  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