全文获取类型
收费全文 | 1237篇 |
免费 | 50篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 13篇 |
化学工业 | 325篇 |
金属工艺 | 36篇 |
机械仪表 | 34篇 |
建筑科学 | 16篇 |
矿业工程 | 2篇 |
能源动力 | 41篇 |
轻工业 | 126篇 |
水利工程 | 2篇 |
石油天然气 | 9篇 |
无线电 | 112篇 |
一般工业技术 | 265篇 |
冶金工业 | 147篇 |
原子能技术 | 21篇 |
自动化技术 | 141篇 |
出版年
2024年 | 5篇 |
2023年 | 15篇 |
2022年 | 33篇 |
2021年 | 33篇 |
2020年 | 38篇 |
2019年 | 20篇 |
2018年 | 38篇 |
2017年 | 49篇 |
2016年 | 29篇 |
2015年 | 23篇 |
2014年 | 42篇 |
2013年 | 78篇 |
2012年 | 65篇 |
2011年 | 76篇 |
2010年 | 62篇 |
2009年 | 44篇 |
2008年 | 54篇 |
2007年 | 50篇 |
2006年 | 38篇 |
2005年 | 40篇 |
2004年 | 28篇 |
2003年 | 20篇 |
2002年 | 25篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 27篇 |
1998年 | 44篇 |
1997年 | 35篇 |
1996年 | 27篇 |
1995年 | 25篇 |
1994年 | 24篇 |
1993年 | 22篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1969年 | 4篇 |
1968年 | 5篇 |
排序方式: 共有1290条查询结果,搜索用时 15 毫秒
1.
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
2.
A generalized effectiveness factor equation (Eq. (32)), in terms of modified Bessel functions, is derived for a catalyst pellet of arbitrary shape. The derivation is based on utilizing an appropriate one-dimensional approximation for the Laplacian in an arbitrary shaped body subjected to a uniform external concentration field. The comparison of the result with the available expressions for various geometries is highly satisfactory. It unifies the expressions for the three fundamental shapes, viz., infinite slab, infinite cylinder and sphere, and also compares very well with the exact solutions for finite shapes over the entire range of the Thiele modulus. 相似文献
3.
4.
5.
6.
In this paper we present a scale model for fitting an ideal shape to an object. The measurements of the object are taken corresponding to a fixed coordinate system at a set of well-defined locations on the surface of the object. We propose an algorithm to estimate the model parameters and hypothesis tests to make statistical inferences about several possible special cases of the general model. The model is tested with an example that analyzes data on the feet of people in Hong Kong. 相似文献
7.
The methodology of response reactions (RERs) introduced earlier from thermodynamic and kinetic considerations is used in this work to develop a new algorithm for the classification and enumeration of unique/direct reaction routes (RRs) and overall reactions (ORs). According to the RERs approach, a unique set of both RRs and ORs may be generated starting from any conceivable set of linearly independent RRs and ORs. In particular, the direct ORs may be most conveniently enumerated starting from the formula matrix of the terminal species (reactants and products), i.e., without any relation to the elementary reactions comprising the detailed mechanism. Depending on the type of ORs produced by the RRs one can distinguish between two distinct types of direct RRs. Namely, one option is to define a direct RR by specifying the intermediate species that need to be eliminated. This type of RR is referred to as Milner RRs. The other option is to require the direct RRs to produce RERs, thus resulting in RRs referred to as Happel-Sellers RRs. 相似文献
8.
José Luiz Antunes de Oliveira e Sousa Ravindra Gettu 《Canadian Metallurgical Quarterly》2006,132(2):141-148
The determination of the fundamental stress versus crack opening (σ-w) response of concrete under uniaxial tension is performed in this study through inverse analysis using data from notched beam tests. The procedure used for optimizing the parameters of the σ-w relation using the load versus crack mouth opening displacement response of the notched beam is described. Satisfactory comparisons have been obtained between the σ-w curves obtained through the inverse analysis and those directly measured in uniaxial tension tests. The use of weighting functions in the inverse analysis may be necessary when large crack widths are to be considered. 相似文献
9.
10.
Palangala S. Ravindra 《Information Systems Management》1987,4(1):74-75
More than just a regulatory body, the data administration group is responsible for planning and promoting the use of information resources. By managing the corporate data base effectively, data administration provides benefits to everyone who depends on the use of accurate information. 相似文献