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   1143篇
  免费   0篇
  国内免费   1篇
电工技术   1篇
综合类   1篇
化学工业   15篇
金属工艺   5篇
机械仪表   47篇
建筑科学   4篇
能源动力   2篇
轻工业   5篇
水利工程   1篇
无线电   19篇
一般工业技术   17篇
冶金工业   1012篇
原子能技术   2篇
自动化技术   13篇
  2018年   1篇
  2017年   1篇
  2016年   3篇
  2015年   2篇
  2013年   6篇
  2012年   2篇
  2011年   3篇
  2010年   2篇
  2009年   4篇
  2008年   2篇
  2007年   2篇
  2006年   3篇
  2005年   2篇
  2004年   3篇
  2003年   6篇
  2002年   3篇
  2001年   5篇
  2000年   1篇
  1999年   22篇
  1998年   272篇
  1997年   146篇
  1996年   131篇
  1995年   68篇
  1994年   63篇
  1993年   73篇
  1992年   14篇
  1991年   18篇
  1990年   14篇
  1989年   20篇
  1988年   21篇
  1987年   18篇
  1986年   19篇
  1985年   25篇
  1984年   6篇
  1983年   4篇
  1982年   13篇
  1981年   16篇
  1980年   11篇
  1979年   7篇
  1978年   6篇
  1977年   27篇
  1976年   65篇
  1975年   4篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1969年   1篇
  1967年   1篇
  1955年   1篇
  1940年   1篇
排序方式: 共有1144条查询结果,搜索用时 15 毫秒
61.
To characterize the clinical features of childhood tuberculosis, we analyzed the symptoms, signs, and laboratory findings of the 89 children with tuberculosis admitted to the Yokohama City University Hospital from 1975 to 1994. Compared with the numbers of patients admitted from 1975 to 1979, those of patients of the past 5 years (from 1990 to 1994) were reduced by half. Of the 89 subjects, 56.2% were below 3 years of age and 24.7% were under 1 year of age. 51.7% had primary complex and 20.2% had serious tuberculosis (tuberculous meningitis 14.6%, miliary tuberculosis 3.4%, and bone and joint tuberculosis 2.2%). Tuberculous children below 3 years of age consisted of primary complex (60.0%) and serious tuberculosis (32.0%). The majority (86.0%) of tuberculous children below 3 years of age had not received BCG vaccination. In 55 (61.8%) of 89 subjects, the sources of tuberculosis were clarified. Of these subjects, 83.6% were infected in the family. The rate of BCG inocluation tended to decrease with decreasing age, especially that of children below 3 years of age was 14.0%. Of the 89 subjects, only 16.9% proved to be smear-positive. Taken together, in order to eliminate tuberculous children below 3 years of age, the following is necessary; (1) BCG inoculation in early infancy, (2) early diagnosis of index cases with adult tuberculosis, and (3) prompt and appropriate family contact examination.  相似文献   
62.
63.
Anxiety levels in a sample of 65 long-term cancer survivors were assessed in a study of the effects of a planned discharge from an oncology clinic. Thirty-one percent of patients scored > or = 8, and 12% > or = 11 on the anxiety subscale of the Hospital Anxiety and Depression Scale (HADS), indicating that anxiety rates in patients in long-standing remission do not greatly differ from patients with active disease. Despite the provision of continued support and guaranteed fast-access return to the clinic if necessary, 28% of patients refused to be discharged. Fear that recurrence would not be detected was the reason most frequently cited. Seventy-five percent of these patients were HADS anxiety cases. A second assessment 4-5 months later of the 41 patients who were discharged showed a slight, but non-significant increase in anxiety rates suggesting that anxiety in cancer survivors may be persistent and not related to clinic attendance.  相似文献   
64.
65.
In response to policy-makers’ increasing claims to prioritise ‘people’ in smart city development, we explore the publicness of emerging practices across six UK cities: Bristol, Glasgow, London, Manchester, Milton Keynes, and Peterborough. Local smart city programmes are analysed as techno-public assemblages invoking variegated modalities of publicness. Our findings challenge the dystopian speculative critiques of the smart city, while nevertheless indicating the dominance of ‘entrepreneurial’ and ‘service user’ modes of the public. We highlight the risk of bifurcation within smart city assemblages, such that the ‘civic’ and ‘political’ roles of the public become siloed into less obdurate strands of programmatic activity.  相似文献   
66.
Our laboratories have documented a significantly high occurrence of chromosome 1p36 rearrangements in non-Hodgkin lymphoma (NHL). The cell division cycle 2-like 1(CDC2L1) (also known as TP58 or PITSLRE) gene, a protein kinase implicated in apoptotic signaling, is located at the very distal region of chromosome 1p36 and is likely to be disrupted by structural rearrangements involving 1p36. To determine the molecular consequences of the recurrent involvement of the 1p36 region, we examined metaphases containing 1p36 abnormalities from 31 specimens derived from 26 patients for the possible deletion of CDC2L1 by fluorescence in situ hybridization (FISH) using the TP58clk-1 DNA probe. Twenty-three cases exhibited the loss of CDC2L1 from the abnormal chromosome 1. In 2 of 26 cases, the gene locus was translocated to the partner chromosome, and in four specimens, all derived from one case, CDC2L1 was not deleted. This pilot investigation suggests that 1p36 rearrangements, and consequently the loss of the CDC2L1 gene locus, is important in NHL. This work also opens avenues for further molecular studies and prognostic correlations.  相似文献   
67.
68.
69.
The potential generated in the smooth muscle of the vas deferens on release of a quantum of transmitter from a varicosity was analyzed using a three-dimensional bidomain continuum model. Current was injected at the origin of the bidomain; this current had the temporal characteristics of the junctional current. The membrane potential, intracellular potential, and extracellular potential, as well as the extracellular current, were then calculated throughout the bidomain at different times. Calculations were performed to show the effect of changing the anisotropy ratios of the intracellular and extracellular conductivities on the spread of current and potential in each of the three dimensions. These results provide a theoretical framework for ascertaining the time course of transmitter interaction at a varicosity following the secretion of a quantum of transmitter.  相似文献   
70.
The diphtheria toxin repressor (DtxR) from Corynebacterium diphtheriae is a divalent-metal activated repressor of chromosomal genes responsible for siderophore-mediated iron-uptake and of a gene on several corynebacteriophages that encodes diphtheria toxin. Even though DtxR is the best characterized iron-dependent repressor to date, numerous key properties of the protein still remain to be explained. One is the role of the cation-anion pair discovered in its first metal-binding site. A second is the reason why zinc exhibits its activating effect only at a concentration 100-fold higher than other divalent cations. In the presently reported 1.85 A resolution Co-DtxR structure at 100K, the sulfate anion in the cation-anion-binding site interacts with three side chains that are all conserved in the entire DtxR family, which points to a possible physiological role of the anion. A comparison of the 1.85 A Cobalt-DtxR structure at 100K and the 2.4 A Zinc-DtxR structure at room temperature revealed no significant differences. Hence, the difference in efficiency of Co2+ and Zn2+ to activate DtxR remains a mystery and might be hidden in the properties of the intriguing second metal-binding site. Our studies do, however, provide a high resolution view of the cationanion-binding site that has most likely evolved to interact not only with a cation but also with the anion in a very precise manner.  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