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   262篇
  免费   15篇
电工技术   5篇
综合类   1篇
化学工业   128篇
金属工艺   19篇
机械仪表   7篇
建筑科学   6篇
矿业工程   3篇
能源动力   5篇
轻工业   4篇
无线电   13篇
一般工业技术   34篇
冶金工业   11篇
原子能技术   2篇
自动化技术   39篇
  2024年   1篇
  2023年   2篇
  2022年   13篇
  2021年   21篇
  2020年   3篇
  2019年   7篇
  2018年   6篇
  2017年   10篇
  2016年   12篇
  2015年   9篇
  2014年   19篇
  2013年   13篇
  2012年   16篇
  2011年   27篇
  2010年   14篇
  2009年   11篇
  2008年   7篇
  2007年   15篇
  2006年   8篇
  2005年   6篇
  2004年   1篇
  2003年   3篇
  2002年   4篇
  2001年   2篇
  2000年   2篇
  1999年   1篇
  1998年   2篇
  1997年   4篇
  1996年   2篇
  1994年   4篇
  1993年   1篇
  1992年   2篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1977年   4篇
  1976年   5篇
  1967年   1篇
排序方式: 共有277条查询结果,搜索用时 10 毫秒
51.
Herein, I present an updated and contextualized literature review of functional genomic studies of natural phenols in the context of cancer. I suggest multilevel chemopreventive and anticancer mechanisms of action, which are shared by multiple dietary natural phenols. Specifically, I cite evidence that curcumin and resveratrol have multilevel anti-cancer effects through: (1) inducing either p53-dependent or p53-independent apoptosis in cancer cell lines, (2) acting as potent regulators of expression of oncogenic and anti-oncogenic microRNAs, and (3) inducing complex epigenetic changes that can switch off oncogenes/switch on anti-oncogenes. There is no simple reductionist explanation for anti-cancer effects of curcumin and resveratrol. More generally, multilevel models of chemoprevention are suggested for related natural phenols and flavonoids such as genistein, quercetin, or luteolin.  相似文献   
52.
53.
The results are presented for the investigations into radioactive waters and sediments of the settling pond in the vicinity of the Vistula River drainage. The possible ways to prevent the environmental contamination are analyzed.  相似文献   
54.
We consider the Cauchy problem for Kowalevskaya-type fractional linear partial differential equations with constant coefficients in two complex variables. We show that the solutions can be analytically continued into certain sectors and have at most exponential growth there if and only if the Cauchy data have an appropriate property. Applying this result to the study of formal power series solutions of non-Kowalevskian linear partial differential equations, we obtain a characterization of Borel summable solutions in terms of analytic continuation property and growth estimations of the Cauchy data. We also obtain a similar result in the case of non-Kowalevskian fractional equations.  相似文献   
55.
A novel criterion for microcrack resistance of multi-phase steels based on property gradient maps is proposed. Two industrial sheets of steel were processed to obtain dual-phase and complex-phase microstructures with exactly the same chemical composition. Experimental investigations showed characteristic differences for the tensile tests, hole expansion and the local plastic behavior during deformation. An innovative full-field modeling approach that explicitly predicts mechanical property gradients as a function of microstructural gradients during forming was developed and validated. This allowed to form a new criterion for evaluation of structure–property relationship in nano-structured multi-phase steels and can reveal the formability limitations.  相似文献   
56.
57.
The main objective of this study is to develop highly active catalyst and its preparation method that would meet the requirements of steel carriers for short-channel structured converters for NOx abatement from stationary biogas engines. The in situ synthesis was applied to deposit a series of Cu-exchanged MFI zeolite (ZSM-5) on kanthal sheets. The samples differ in preparation conditions: organic template assisted and template-free synthesis, Si/Al ratio and catalyst carrier pretreatment (calcined vs. non-calcined). Dip-coating method was used as a reference to compare loading efficiency. In order to evaluate preparation quality and purity of resulting structure the samples were examined by XRD and SEM/EDS at various stages of preparation. For the assessment of mechanical endurance of the deposited catalyst layers the ultrasonication method was used. The results demonstrated high depositing efficiency of the in situ synthesis as well as high activity and selectivity of the Cu-exchanged MFI samples prepared without costly organic template.  相似文献   
58.
59.
Structural health monitoring (SHM) has become a hot and intensively researched field in civil engineering. Thereinto, damage identification play an important role in maintaining structural integrity and safety. Many effective methods have been proposed for damage identification. However, accurate global identification of large real-world structures is not easy due to their complex and often unknown boundary conditions, nonlinear components, insensitivity of global response to localized damages, etc. Furthermore, global identification often requires lots of sensors and involves large number of unknowns. This is costly, rarely feasible in practice, and usually yields severely ill-conditioned identification problems. Substructuring approach is a possible solution: substructuring methods can focus on local small substructures; they need only a few sensors placed on the substructure and yield smaller and numerically much more feasible identification problems. This paper proposed an improved substructure method using local free response for substructure damage identification. The virtual supports are constructed by Substructure Isolation Method (SIM) using the linear combination of the substructural responses. The influence of the global errors is isolated by adding the virtual supports on the main degree of freedoms (DOFs) of the substructure. Through the correlation analysis, the substructural modes are selected and used for damage identification of the substructure. A plain model of cable stayed bridge is used for the verification of the proposed method.  相似文献   
60.
This paper considers iterative learning control law design for both trial-to-trial error convergence and along the trial performance. It is shown how a class of control laws can be designed using the theory of linear repetitive processes for this problem where the computations are in terms of linear matrix inequalities (LMIs). It is also shown how this setting extends to allow the design of robust control laws in the presence of uncertainty in the dynamics produced along the trials. Results from the experimental application of these laws on a gantry robot performing a pick and place operation are also given.  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