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   566篇
  免费   0篇
  国内免费   3篇
电工技术   1篇
综合类   5篇
化学工业   8篇
金属工艺   2篇
机械仪表   2篇
建筑科学   1篇
轻工业   5篇
无线电   3篇
一般工业技术   2篇
冶金工业   535篇
原子能技术   1篇
自动化技术   4篇
  2022年   1篇
  2021年   1篇
  2020年   2篇
  2019年   1篇
  2018年   1篇
  2016年   1篇
  2013年   3篇
  2012年   1篇
  2011年   7篇
  2010年   1篇
  2009年   2篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2004年   1篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1999年   18篇
  1998年   156篇
  1997年   84篇
  1996年   67篇
  1995年   45篇
  1994年   20篇
  1993年   24篇
  1992年   1篇
  1991年   5篇
  1990年   8篇
  1989年   2篇
  1988年   2篇
  1987年   9篇
  1986年   6篇
  1985年   7篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1980年   1篇
  1978年   2篇
  1977年   28篇
  1976年   46篇
  1975年   2篇
  1973年   1篇
  1964年   1篇
排序方式: 共有569条查询结果,搜索用时 453 毫秒
31.
The aim of this study was to investigate the subjective experience of acquired deafness using quantitative (questionnaire) and qualitative (interview) methods. This paper presents findings from the questionnaire data. Eighty-seven people (of whom 38 had acquired a profound loss) participated in the study. The questionnaire contained items designed to examine both audiological and non-audiological aspects of deafened people's experiences. It also sought to measure the extent to which those aspects affect their quality of life. The questionnaire included three variables (i.e. reported frequency and impact of depression, and overall effect of deafness on one's life) as broad indicators of adjustment. Seventy-three respondents (including all but one of the profound group) completed the questionnaire. Factor analysis of the questionnaire data identified six major themes (with variance > 10%) underlying the personal experience of acquired deafness. Three themes--communicative deprivation, restriction, and malinteraction by hearing people--dealt with observable aspects of respondents' experience. Multiple regression found that these factor themes associated with biomedical variables. The remaining three themes dealt with less tangible aspects of the deafness experience. These themes--feelings of distress in interaction, feelings of abandonment and benefit from positive experiences--did not associate with biomedical variables. Finally, multiple regression indicates that respondents' factor scores predict the impact of deafness at least as strongly as their audiological and social characteristics.  相似文献   
32.
33.
A comparative study of two techniques for the PCR genotyping of highly polymorphic tandem repeats was carried out by the example of a triplet repeat in the myotonin protein kinase gene. Sequencing denaturing gels were shown to yield more precise results in the analysis of amplification products.  相似文献   
34.
35.
Population-based genetic associations have been reported between RFLPs detected with probes corresponding to the genes encoding the beta chain of the T-cell receptor for antigen (TCRB) and a variety of autoimmune disorders. In the case of multiple sclerosis (MS), these studies have localized a putative disease-associated gene to a region of approximately 110 kb in length, located within the TCRB locus. In the current study, all 14 known TCRBV (variable region) genes within the region of localization were mapped and identified. The nucleotide sequences of these genes were determined in a panel of six MS patients and six healthy controls, who were human-leukocyte antigen and TCRB-RFLP haplotype matched. Nine of the 14 TCRBV genes studied showed evidence of polymorphism. PCR-based assays for each of these polymorphic genes were developed, and allele and genotype frequencies were determined in a panel of DNA samples from 48 MS patients and 60 control individuals. No significant differences in allele, genotype, or phenotype frequencies were observed between the MS patients and controls for any of the 14 TCRBV-gene polymorphisms studied. In light of the extensive linkage disequilibrium across the region studied, the saturating numbers of polymorphisms examined, and the direct sequence analysis of all BV genes in the region, these results suggest that it is unlikely that germ-line polymorphism in the TCRBV locus makes a major contribution to MS susceptibility.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
36.
37.
38.
We report 18 patients who presented prior to age 20 years with epilepsy or fixed neurologic deficits. MRI showed signal abnormality extending from the cortex to the superolateral wall of the lateral ventricle. Histology showed cortical disorganization, neuronal cytomegaly, balloon cells, indistinct cortical gray matter-white matter junctions, and variable accompanying astrogliosis. We propose that this transmantle dysplasia is a specific anomaly resulting from abnormal stem cell development.  相似文献   
39.
40.
Overall ninety patients with chronic obstructive bronchitis presenting with signs of varying degree cardiopulmonary insufficiency (CPI) were evaluated by radionuclide ventriculography with technetium pertechnetate as well as by rotational viscosimetry of blood. The degree of hemorheological derangements tended to get higher with CPI severity (light, moderately severe, severe) being accompanied by progressing impairement of systolic and diastolic functions of both ventricles of the heart. Mechanisms of compensation of endocardiac hemodynamics were realized as a result of increase in end-diastolic and end-systolic volumes of both ventricles together with changes in amplitude and time characteristics of processes of ventricular ejection and filling. Forecast of the probable course of the condition may rely upon the functional state of right as well as left ventricle of the heart.  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