全文获取类型
收费全文 | 1752篇 |
免费 | 43篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 26篇 |
化学工业 | 270篇 |
金属工艺 | 47篇 |
机械仪表 | 37篇 |
建筑科学 | 59篇 |
矿业工程 | 14篇 |
能源动力 | 62篇 |
轻工业 | 114篇 |
水利工程 | 16篇 |
石油天然气 | 4篇 |
无线电 | 204篇 |
一般工业技术 | 372篇 |
冶金工业 | 387篇 |
原子能技术 | 6篇 |
自动化技术 | 180篇 |
出版年
2023年 | 13篇 |
2022年 | 29篇 |
2021年 | 53篇 |
2020年 | 42篇 |
2019年 | 47篇 |
2018年 | 45篇 |
2017年 | 33篇 |
2016年 | 32篇 |
2015年 | 36篇 |
2014年 | 43篇 |
2013年 | 96篇 |
2012年 | 52篇 |
2011年 | 72篇 |
2010年 | 68篇 |
2009年 | 61篇 |
2008年 | 48篇 |
2007年 | 47篇 |
2006年 | 35篇 |
2005年 | 36篇 |
2004年 | 26篇 |
2003年 | 30篇 |
2002年 | 31篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 28篇 |
1998年 | 114篇 |
1997年 | 69篇 |
1996年 | 50篇 |
1995年 | 42篇 |
1994年 | 34篇 |
1993年 | 37篇 |
1992年 | 19篇 |
1991年 | 12篇 |
1990年 | 17篇 |
1989年 | 23篇 |
1988年 | 27篇 |
1987年 | 23篇 |
1986年 | 14篇 |
1985年 | 35篇 |
1984年 | 18篇 |
1983年 | 17篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 26篇 |
1979年 | 17篇 |
1978年 | 7篇 |
1977年 | 19篇 |
1976年 | 30篇 |
1975年 | 7篇 |
1974年 | 12篇 |
排序方式: 共有1798条查询结果,搜索用时 31 毫秒
1.
2.
Shank S. Kulkarni Kyoo Sil Choi Wenbin Kuang Nalini Menon Bernice Mills Ayoub Soulami Kevin Simmons 《International Journal of Hydrogen Energy》2021,46(36):19001-19022
The use of hydrogen as a fuel is increasing exponentially, and the most economical way to store and transport hydrogen for fuel use is as a high-pressure gas. Polymers are widely used for hydrogen distribution and storage systems because they are chemically inert towards hydrogen. However, when exposed to high-pressure hydrogen, some hydrogen diffuses through polymers and occupies the preexisting cavities inside the material. Upon depressurization, the hydrogen trapped inside polymer cavities can cause blistering or cracking by expanding these cavities. A continuum mechanics–based deformation model was deployed to predict the stress distribution and damage propagation while the polymer undergoes depressurization after high-pressure hydrogen exposure. The effects of cavity size, cavity location, and pressure inside the cavity on damage initiation and evolution inside the polymer were studied. The stress and damage evolution in the presence of multiple cavities was also studied, because interaction among cavities alters the damage and stress field. It was found that all these factors significantly change the stress state in the polymer, resulting in different paths for damage propagation. The effect of adding carbon black filler particles and plasticizer on the damage was also studied. It was found that damage tolerance of the polymer increases drastically with the addition of carbon black fillers, but decreases with the addition of the plasticizer. 相似文献
3.
Deshamukhya Tuhin Bhanja Dipankar Nath Sujit 《Neural computing & applications》2021,33(19):12605-12619
Neural Computing and Applications - The advanced high-end gadgets and sophisticated machines require effective mechanism of transferring heat away from the sources. In a large number of... 相似文献
4.
5.
6.
Y. Nath P. C. Dumir R. S. Bhatiaf 《International journal for numerical methods in engineering》1985,21(3):565-578
The present work investigates the efficacy and applicability of interior global orthogonal point collocation method to the axisymmetric nonlinear analysis of elastic circular plates and shallow spherical shells subjected to uniformly distributed transverse load. Spacewise discretisation has been carried out using a polynomial expansion with the zeros of a Chebyshev polynomial as collocation points. Timewise integration has been carried out with Newmark k-β scheme corresponding to average acceleration method. The static response and snap-through buckling results, as well as, the dynamic response and dynamic buckling results under a uniformly distributed step load have been obtained and found to agree closely with the available results. 相似文献
7.
Application of the extremum stack to neurological MRI 总被引:2,自引:0,他引:2
Simmons A. Arridge S.R. Tofts P.S. Barker G.J. 《IEEE transactions on medical imaging》1998,17(3):371-382
8.
Support vector clustering involves three steps—solving an optimization problem, identification of clusters and tuning of hyper-parameters. In this paper, we introduce a pre-processing step that eliminates data points from the training data that are not crucial for clustering. Pre-processing is efficiently implemented using the R*-tree data structure. Experiments on real-world and synthetic datasets show that pre-processing drastically decreases the run-time of the clustering algorithm. Also, in many cases reduction in the number of support vectors is achieved. Further, we suggest an improvement for the step of identification of clusters. 相似文献
9.
Knowledge conceptualization tool 总被引:3,自引:0,他引:3
Fujihara H. Simmons D.B. Ellis N.C. Shannon R.E. 《Knowledge and Data Engineering, IEEE Transactions on》1997,9(2):209-220
Knowledge acquisition is one of the most important and problematic aspects of developing knowledge-based systems. Many automated tools have been introduced in the past, however, manual techniques are still heavily used. Interviewing is one of the most commonly used manual techniques for a knowledge acquisition process, and few automated support tools exist to help knowledge engineers enhance their performance. The paper presents a knowledge conceptualization tool (KCT) in which the knowledge engineer can effectively retrieve, structure, and formalize knowledge components, so that the resulting knowledge base is accurate and complete. The KCT uses information retrieval technique to facilitate conceptualization, which is one of the human intensive activities of knowledge acquisition. Two information retrieval techniques employing best-match strategies are used: vector space model and probabilistic ranking principle model. A prototype of the KCT was implemented to demonstrate the concept. The results from KCT are compared with the outputs from a manual knowledge acquisition process in terms of amount of information retrieved and the process time spent. An analysis of the results shows that the process time to retrieve knowledge components (e.g., facts, rules, protocols, and uncertainty) of KCT is about half that of the manual process, and the number of knowledge components retrieved from knowledge acquisition activities is four times more than that retrieved through a manual process 相似文献
10.
The nonsimilar and self-similar flows for the steady natural convection over a vertical heated surface in a saturated porous medium with mass transfer using non-Darcy model have been studied under boundary layer approximations. The differential equations governing both the nonsimilar and self-similar flows have been solved numerically using an implicit finite-difference scheme developed by Keller. The results indicate that both heat transfer and velocity field are appreciably affected by the modified Grashof number and mass transfer except that the effect of the modified Grashof number on the heat transfer for large suction is very small. It is found that the maximum velocity occurs at the wall and it increases as the modified Grashof number or injection increases. 相似文献