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   336篇
  免费   9篇
电工技术   8篇
化学工业   56篇
金属工艺   10篇
机械仪表   5篇
建筑科学   6篇
能源动力   7篇
轻工业   19篇
水利工程   2篇
无线电   24篇
一般工业技术   85篇
冶金工业   85篇
原子能技术   4篇
自动化技术   34篇
  2023年   2篇
  2022年   6篇
  2021年   10篇
  2020年   2篇
  2019年   6篇
  2018年   8篇
  2017年   1篇
  2016年   7篇
  2015年   4篇
  2014年   7篇
  2013年   14篇
  2012年   18篇
  2011年   14篇
  2010年   14篇
  2009年   7篇
  2008年   26篇
  2007年   14篇
  2006年   7篇
  2005年   12篇
  2004年   11篇
  2003年   11篇
  2002年   7篇
  2001年   3篇
  2000年   4篇
  1999年   3篇
  1998年   30篇
  1997年   17篇
  1996年   16篇
  1995年   14篇
  1994年   5篇
  1993年   6篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1989年   3篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   2篇
  1984年   4篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1978年   1篇
  1976年   7篇
  1974年   1篇
  1973年   1篇
  1967年   1篇
排序方式: 共有345条查询结果,搜索用时 0 毫秒
101.
102.
103.
104.
A charge–discharge cycling test of a Li/LiCoO2 cell containing ionic liquids based on bis(fluorosulfonyl)imide ([FSI]) as the electrolyte media, revealed significantly better rate properties compared to those of cells using conventional ionic liquids. The use of an 1-ethyl-3-methylimidazolium (EMI+) salt permitted the retention of 70% of the discharge capacity at a 4 C current rate. In contrast, similar performance of cells containing N-methyl-N-propylpyrrolidinium (Py13+) and N-methyl-N-propylpiperidinium (PP13+) salts of [FSI] was limited to operation at 2 and 1 C current rates, respectively. However, the charge/discharge cycling stability of the cell with Py13[FSI] was much better than that of the cell using EMI[FSI].  相似文献   
105.
We removed B-, P-, and As-ion-implanted positive-tone novolak resists with an implantation dose of 5 × 1012 to 5 × 1015 atoms/cm2 at 70 keV, using atomic hydrogen. Though the removal rate decreased with increase in the implantation dose, all of the ion-implanted resists were removed. The rates of thickness of the surface-hardened layer/all resist layer of B, P, and As implanted resists were 0.38, 0.26, and 0.16, respectively, by SEM observation. The removal rate decreased with increasing the rate of the surface-hardened layer. The energy supplied from the ions to the resist concentrated on the surface side in the increasing order of B-P-As.  相似文献   
106.
The B phase of the topological superfluid $^3$ He ( $^3$ He-B) shows many exotic phenomena at a surface as well as in bulk. In this article, we describe the first study of the nonlinear transport behavior of positive ions trapped below a free surface of $^3$ He-B measured at very low temperatures (below 300  ${\upmu }$ K), investigated for the purposes of observing the Landau critical velocity for pair breaking and finding a signature of the Majorana surface Andreev bound states. We observe that nonlinearity sets in at a velocity smaller than the Landau critical velocity for bulk pair breaking, and find that the nonlinear behavior does not depend on the depth of the trapped ions even though the depth is varied over the coherence length. The lack of depth dependence indicates that the nonlinear behavior does not reflect properties of the surface Andreev bound states. The onset of the nonlinearity at a velocity smaller than the bulk pair breaking velocity might be due to the inelastic scattering of bulk quasiparticles.  相似文献   
107.
108.
The current‐carrying capacity (CCC), or ampacity, of highly‐conductive, light, and strong carbon nanotube (CNT) fibers is characterized by measuring their failure current density (FCD) and continuous current rating (CCR) values. It is shown, both experimentally and theoretically, that the CCC of these fibers is determined by the balance between current‐induced Joule heating and heat exchange with the surroundings. The measured FCD values of the fibers range from 107 to 109 A m?2 and are generally higher than the previously reported values for aligned buckypapers, carbon fibers, and CNT fibers. To the authors’ knowledge, this is the first time the CCR for a CNT fiber has been reported. The specific CCC value (i.e., normalized by the linear mass density) of these CNT fibers are demonstrated to be higher than those of copper.  相似文献   
109.
Bladder inflammatory diseases cause various urinary symptoms, such as urinary frequency and painful urination, that impair quality of life. In this study, we used a mouse model of cyclophosphamide (CYP)-induced bladder inflammation and immortalized human urothelial (TRT-HU1) cells to explore the preventive potential of nobiletin (NOB), a polymethoxylated flavone enriched in citrus fruit peel, and investigate its mechanism of action in the bladder. Prophylaxis with PMF90 (60% NOB) attenuated the development of bladder inflammation and urinary symptoms in CYP-treated mice. PMF90 also reduced the upregulation of connexin 43 (Cx43), a major component of gap junction channels, in the bladder mucosa of CYP-treated mice. Stimulation of TRT-HU1 cells with the pro-inflammatory cytokine IL-1β increased Cx43 mRNA and protein expression and enhanced gap junction coupling—responses that were prevented by pre-treatment with NOB. In urothelium-specific Cx43 knockout (uCx43KO) mice, macroscopic signs of bladder inflammation and changes in voiding behavior induced by CYP treatment were significantly attenuated when compared to controls. These findings indicate the participation of urothelial Cx43 in the development of bladder inflammation and urinary symptoms in CYP-treated mice and provide pre-clinical evidence for the preventive potential of NOB through its anti-inflammatory effects on IL-1β signaling and urothelial Cx43 expression.  相似文献   
110.
Susceptibility to systemic lupus erythematosus has been unequivocally established to be an inherited trait, but the exact genes and how they confer susceptibility remain largely unknown. In this study of (NZB x NZW)F2 intercross mice, we used linkage analysis of markers covering > 90% of the autosomal genome and identified eight susceptibility loci (Lbw1 to -8, chromosomes 17, 4-7, 18, 1, 11, respectively) associated with antichromatin autoantibody production, glomerulonephritis, and/or mortality. Only one locus, the major histocompatibility complex, was linked to all three traits. Two other loci were associated with both glomerulonephritis and mortality, whereas the remaining loci were linked to one of the above traits. Two additional loci (Sbw1 and -2) that contributed to splenomegaly were also identified. The Sbw2 locus mapped to the identical region as Lbw2, a locus on chromosome 4 linked to glomerulonephritis and mortality, suggesting a single locus with pleiotropic effects. The results indicate that the immunopathologic features of lupus are affected by distinct, but additive, genetic contributions. Studies to determine the nature of the genes associated with these loci should help define the genetic mechanisms involved in this systemic autoimmune disease.  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