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   796篇
  免费   39篇
  835篇
  2022年   2篇
  2021年   5篇
  2020年   4篇
  2019年   3篇
  2018年   5篇
  2017年   8篇
  2016年   12篇
  2015年   17篇
  2014年   20篇
  2013年   46篇
  2012年   55篇
  2011年   47篇
  2010年   33篇
  2009年   29篇
  2008年   37篇
  2007年   54篇
  2006年   45篇
  2005年   53篇
  2004年   64篇
  2003年   56篇
  2002年   47篇
  2001年   12篇
  2000年   18篇
  1999年   25篇
  1998年   9篇
  1997年   12篇
  1996年   6篇
  1995年   9篇
  1994年   10篇
  1993年   6篇
  1992年   6篇
  1991年   12篇
  1990年   5篇
  1989年   6篇
  1988年   6篇
  1987年   4篇
  1986年   6篇
  1985年   2篇
  1984年   5篇
  1982年   3篇
  1981年   5篇
  1980年   8篇
  1978年   2篇
  1977年   2篇
  1975年   3篇
  1974年   2篇
  1973年   2篇
  1969年   1篇
  1968年   1篇
  1962年   1篇
排序方式: 共有835条查询结果,搜索用时 15 毫秒
121.
122.
123.

Background

Despite being expensive, the standard combination of pegylated interferon (Peg-IFN)- α and ribavirin used to treat chronic hepatitis C (CH) results in a moderate clearance rate and a plethora of side effects. This makes it necessary to predict patient outcome so as to improve the accuracy of treatment. Although the antiviral mechanism of genetically altered IL28B is unknown, IL28B polymorphism is considered a good predictor of IFN combination treatment outcome.

Methodology

Using microarray, we quantified the expression profile of 237 IFN related genes in 87 CH liver biopsy specimens to clarify the relationship between IFN pathway and viral elimination, and to predict patients'' clinical outcome. In 72 out of 87 patients we also analyzed IL28B polymorphism (rs8099917).

Principal Findings

Five IFN related-genes (IFI27, IFI 44, ISG15, MX1, and OAS1) had expression levels significantly higher in nonresponders (NR) than in normal liver (NL) and sustained virological responders (SVR); this high expression was also frequently seen in cases with the minor (TG or GG) IL28B genotype. The expression pattern of 31 IFN related-genes also differed significantly between NR and NL. We predicted drug response in NR with 86.1% accuracy by diagonal linear discriminant analysis (DLDA).

Conclusion

IFN system dysregulation before treatment was associated with poor IFN therapy response. Determining IFN related-gene expression pattern based on patients'' response to combination therapy, allowed us to predict drug response with high accuracy. This method can be applied to establishing novel antiviral therapies and strategies for patients using a more individual approach.  相似文献   
124.
The effects of synthetic atrial natriuretic factor (ANF) were studied in superfused rat posterior pituitary gland. ANF (10(-6)M, 10(-10)M) significantly inhibited basal as well as KC1 (50 mM) or angiotensin II-stimulated immunoreactive arginine vasopressin secretion. The magnitude of inhibition was greater at 10(-6)M than at 10(-10)M. ANF also decreased cAMP secretion and increased cGMP secretion from the posterior pituitary. These results suggest that ANF directly acts on the posterior pituitary to inhibit arginine vasopressin secretion and that this effect is, at least, partly mediated by the changes in cyclic nucleotide production.  相似文献   
125.
126.
We previously demonstrated that IL-4 gene-transfected glioma cell vaccines induce effective therapeutic immunity in preclinical glioma models, and have initiated phase I trials of these vaccines in patients with malignant gliomas. To gain additional mechanistic insight into the efficacy of this approach, we have treated mice bearing the MCA205 (H-2(b)) or CMS-4 (H-2(d)) sarcomas. IL-12/23 p40(-/-) and IFN-gamma(-/-) mice, which were able to reject the initial inoculation of IL-4 expressing tumors, failed to mount a sustained systemic response against parental (nontransfected) tumor cells. Paracrine production of IL-4 in vaccine sites promoted the accumulation and maturation of IL-12p70-secreting tumor-infiltrating dendritic cells (TIDCs). Adoptive transfer of TIDCs isolated from vaccinated wild-type, but not IL-12/23 p40(-/-), mice were capable of promoting tumor-specific CTL responses in syngeneic recipient animals. Interestingly, both STAT4(-/-) and STAT6(-/-) mice failed to reject IL-4-transfected tumors in concert with the reduced capacity of TIDCs to produce IL-12p70 and to promote specific antitumor CTL reactivity. These results suggest that vaccines consisting of tumor cells engineered to produce the type 2 cytokine, IL-4, critically depend on type 1 immunity for their observed therapeutic efficacy.  相似文献   
127.
We studied x-ray diffraction from the left ventricular wall of an excised, perfused whole heart of a rat using x rays from the third-generation synchrotron radiation facility, SPring-8. With the beam at right angles to the long axis of the left ventricle, well-oriented, strong equatorial reflections were observed from the epicardium surface. The reflections became vertically split arcs when the beam passed through myocardium deeper in the wall, and rings were observed when the beam passed into the inner myocardium of the wall. These diffraction patterns were explained by employing a layered-spiral model of the arrangement of muscle fibers in the heart. In a quiescent heart with an expanded left ventricle, the muscle fibers at the epicardium surface were found to have a (1,0) lattice spacing smaller than in the rest of the wall. The intensity ratio of the (1,0) and (1,1) equatorial reflections decreased on contraction with a similar time course in all parts of the wall. The results show that it is possible to assign the origin of reflections in a diffraction diagram from a whole heart. This study offers a basis for interpretation of x-ray diffraction from a beating heart under physiologically and pathologically different conditions.  相似文献   
128.
129.
The number of cellular phone subscribers is increasing every year and there have been reports of health disorders related to the high-frequency radio waves. This paper considers the dependence of Thai university and high school students on cellular phones. A survey form (cellular phone dependence questionnaire: CPDQ) was distributed to 181 female and 177 male Thai university students and to 240 female and 140 male Thai high school students. The surveys were collected, Cronbach alpha coefficient was calculated, and a factor analysis was performed using the principal factor method and varimax rotation. The total scores were 16.54 to 20.04 and the Cronbach's alpha coefficients were 0.808 to 0.930. According to a factor analysis of 20 scored items, 4 factors were extracted for both male and female high school students, and the cumulative correlation coefficients of the male and female groups were 64.85% and 62.70%, respectively. Five factors were extracted for male university students and 6 factors were extracted for female university students, and the cumulative correlation coefficients were 58.08% and 57.91%, respectively. The W value results of the Shapiro-Wilk W-test for male university students, female university students, male high school students and female high school students were 0.969, 0.984, 0.964, and 0.913 respectively, thus verifying the normality of the score distributions.The total scores for the Thai university students were higher than the scores for the Thai high school students. The factor analysis of female high school students confirmed a large difference compared to male university students, male high school students, and Japanese female university students. (The Japanese students were surveyed in an earlier study by Toda et al.). Also, the CPDQ total score was high, which indicated a strong tendency toward dependence.  相似文献   
130.
Efficient catalytic and stereoselective glycosylation was achieved by activating a glycosyl N-trichloroacetylcarbamate with a catalytic amount of Lewis acid in the presence of a glycosyl acceptor and 5 ? molecular sieves. Catalytic one-pot dehydrative glycosylation of a 1-hydroxy carbohydrate was achieved stereoselectively by reaction with trichloroacetyl isocyanate, followed by activation with a catalytic amount of activators.  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