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   169篇
  免费   8篇
  国内免费   1篇
电工技术   7篇
化学工业   30篇
金属工艺   3篇
机械仪表   4篇
建筑科学   6篇
能源动力   7篇
轻工业   31篇
水利工程   2篇
石油天然气   1篇
无线电   6篇
一般工业技术   24篇
冶金工业   23篇
自动化技术   34篇
  2022年   4篇
  2021年   9篇
  2020年   2篇
  2019年   1篇
  2018年   11篇
  2017年   4篇
  2016年   7篇
  2015年   7篇
  2014年   12篇
  2013年   12篇
  2012年   13篇
  2011年   17篇
  2010年   8篇
  2009年   9篇
  2008年   6篇
  2007年   7篇
  2006年   8篇
  2005年   2篇
  2004年   5篇
  2003年   5篇
  2002年   3篇
  2001年   4篇
  2000年   3篇
  1999年   2篇
  1998年   1篇
  1997年   4篇
  1996年   2篇
  1995年   1篇
  1994年   3篇
  1989年   1篇
  1986年   1篇
  1983年   2篇
  1982年   1篇
  1976年   1篇
排序方式: 共有178条查询结果,搜索用时 31 毫秒
21.
Introduction of an integrated energy service system in an urban area is assumed. An energy supply plant is installed in the area to provide integrated energy service. It supplies electricity, gas, cooling, and heating to consumers. To consider CO/sub 2/ emission constraint in the area, analyses of energy pricing, economic impact on energy consumers, and operation of the system under the constraint of CO/sub 2/ emission were performed. CO/sub 2/ emission and economic impact on the consumers and the supplier of various energy pricing scenarios were calculated using linear programming models. The solution that satisfied the CO/sub 2/ emission restriction, and was economically optimal to the consumers was chosen from the results. The chosen solutions are Pareto optimum solutions of a multiobjective problem that concerns both CO/sub 2/ emission and cost to the consumers.  相似文献   
22.
23.
This article analyses regional labor market adjustment in the Finnish provinces during 1976–2000. We investigate the inter-relations of employment, unemployment, labor force participation, and migration to see how a change in region-specific and total labor demand is adjusted. The analysis reveals that region-specific labor demand shocks adjust mainly via participation, whereas total shocks are adjusted by unemployment. The region-specific component of labor demand shock has shorter-lived effects on unemployment and participation, but its effect on employment is permanent. Conversely, total shocks leave no permanent effect. Migration is more important in the region-specific case where, after a few years, it acquires a large role in the adjustment process.  相似文献   
24.
The deletion of MCD4 leads to an increase in beta-1,6-glucan level and a decrease in glycosylphosphatidylinositol-anchored protein and mannan levels in the cell wall of Saccharomyces cerevisiae, suggesting that mcd4 deletion mutant (mcd4Delta) displays beta-glucans on the cell surface without a mannan cover. An observation of the cell surface of mcd4Delta cells and an examination of the effect of contact between mcd4Delta cells and mouse macrophages indicated that macrophages were activated by contact with mcd4Delta cells displaying beta-glucans on the cell surface. We further examined the effect of intraperitoneal ethanol-fixed mcd4Delta cells on the survival period of mice infected with Candida albicans. mcd4Delta cells prolonged the survival period, implying that mcd4Delta cells may enhance the immune function of mice via macrophage activation. Moreover, we examined the structures of beta-glucans (i.e., alkali- and acetic acid-insoluble beta-glucans) extracted from mcd4Delta with (13)C-NMR and the effect of extracted beta-glucans on TNF-alpha secretion from macrophages. The structures of the beta-glucans from mcd4Delta differed from those of wild type (WT); however, there was no difference in tumor necrosis factor-alpha (TNF-alpha) secretion level between beta-glucans from mcd4Delta and those from WT. The yield of purified beta-glucans obtained from dry cells of mcd4Delta was higher than that obtained from dry cells of WT. mcd4Delta may be a superior strain for the preparation of beta-glucans.  相似文献   
25.
Various stresses latently induce cellular senescence that occasionally deteriorates the functioning of surrounding tissues. Nevertheless, little is known about the appearance and function of senescent cells, caused by the implantation of beta-tricalcium phosphate (β-TCP)—used widely in dentistry and orthopedics for treating bone diseases. In this study, two varying sizes of β-TCP granules (<300 μm and 300–500 μm) were implanted, and using histological and immunofluorescent staining, appearances of senescent-like cells in critical-sized bone defects in the calvaria of Sprague Dawley rats were evaluated. Parallelly, bone formation in defects was investigated with or without the oral administration of senolytics (a cocktail of dasatinib and quercetin). A week after the implantation, the number of senescence-associated beta-galactosidase, p21-, p19-, and tartrate-resistant acid phosphatase-positive cells increased and then decreased upon administrating senolytics. This administration of senolytics also attenuated 4-hydroxy-2-nonenal staining, representing reactive oxygen species. Combining senolytic administration with β-TCP implantation significantly enhanced the bone formation in defects as revealed by micro-computed tomography analysis and hematoxylin-eosin staining. This study demonstrates that β-TCP granules latently induce senescent-like cells, and senolytic administration may improve the bone-forming ability of β-TCP by inhibiting senescence-associated mechanisms.  相似文献   
26.
27.
28.
The weight of skeletal muscle accounts for approximately 40% of the whole weight in a healthy individual, and the normal metabolism and motor function of the muscle are indispensable for healthy life. In addition, the skeletal muscle of the maxillofacial region plays an important role not only in eating and swallowing, but also in communication, such as facial expressions and conversations. In recent years, skeletal muscle atrophy has received worldwide attention as a serious health problem. However, the mechanism of skeletal muscle atrophy that has been clarified at present is insufficient, and a therapeutic method against skeletal muscle atrophy has not been established. This review provides views on the importance of skeletal muscle in the maxillofacial region and explains the differences between skeletal muscles in the maxillofacial region and other regions. We summarize the findings to change in gene expression in muscle remodeling and emphasize the advantages and disadvantages of denervation-induced skeletal muscle atrophy model. Finally, we discuss the newly discovered beneficial effects of natural compounds on skeletal muscle atrophy.  相似文献   
29.
Structural-based mutational analysis of salt-tolerant glutaminase from Micrococcus luteus K-3 (Micrococcus glutaminase) revealed that three amino acid residues, S64, K67, and E160, were essential to a catalytic reaction. The result suggested that Micrococcus glutaminase had a possible catalytic mechanism similar to class A beta-lactamase rather than glutaminase-asparaginase from Pseudomonas 7A.  相似文献   
30.
The present study investigates changes in blood vessel stability and its regulation in the corpus luteum (CL) during pregnancy in the rat. First, blood vessel stability in the CL was evaluated during pregnancy based on vascular leakage, which was quantified by the Evans blue assay. Vascular leakage was highest on day 3, thereafter decreased until day 15 and increased again on day 21. Secondly, to study the regulation of vascular leakage, the expression of angiopoietins was examined in the CL during pregnancy. Angiopoietin-1 (Ang-1) effects maturation and stabilization of newly formed blood vessels, while Ang-2 produces the opposite effect by allowing vascular remodeling. An immunohistochemical study showed both Ang-1 and Ang-2 expression in luteal cells. mRNA and protein levels of Ang-1 were significantly higher on days 12 and 15 than those on days 3 and 21, whereas there was no significant change in Ang-2 expression. Since estradiol contributes to CL development during mid-pregnancy, we finally studied whether estradiol regulates vascular leakage and angiopoietin expression. Rats undergoing hypophysectomy and hysterectomy (hypox-hect) on day 12 were treated with estradiol until day 15. Vascular leakage was increased and Ang-1 expression was decreased by hypox-hect, and these effects were completely reversed by estradiol treatment. In conclusion, blood vessel stability in the CL is likely to be associated with CL development and CL regression, and may be regulated by angiopoietins. Estradiol contributes to blood vessel stabilization in the CL during mid-pregnancy, which is associated with an increase in Ang-1 expression.  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