全文获取类型
收费全文 | 1096篇 |
免费 | 95篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 347篇 |
金属工艺 | 32篇 |
机械仪表 | 25篇 |
建筑科学 | 36篇 |
矿业工程 | 3篇 |
能源动力 | 43篇 |
轻工业 | 130篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 42篇 |
一般工业技术 | 257篇 |
冶金工业 | 17篇 |
原子能技术 | 9篇 |
自动化技术 | 231篇 |
出版年
2023年 | 9篇 |
2022年 | 9篇 |
2021年 | 42篇 |
2020年 | 27篇 |
2019年 | 30篇 |
2018年 | 71篇 |
2017年 | 50篇 |
2016年 | 82篇 |
2015年 | 56篇 |
2014年 | 62篇 |
2013年 | 126篇 |
2012年 | 50篇 |
2011年 | 62篇 |
2010年 | 76篇 |
2009年 | 66篇 |
2008年 | 55篇 |
2007年 | 38篇 |
2006年 | 22篇 |
2005年 | 8篇 |
2004年 | 8篇 |
2003年 | 9篇 |
2002年 | 14篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 5篇 |
排序方式: 共有1194条查询结果,搜索用时 15 毫秒
1.
2.
3.
Bedich ika Helena Bendov Ivan Macha
《Chemical Engineering and Processing: Process Intensification》2005,44(12):1312-1319
A procedure has been proposed for the estimation of the terminal falling velocity of non-spherical particles moving in a Carreau model fluid in the transition flow region. The procedure is based on a modification of the relationship formerly developed for the fall of spherical particles including the particle dynamic shape factor. The suitability of the proposed procedure has been confirmed by good agreement between experimental and calculated terminal falling velocity data. In the experiments, the terminal falling velocity of short cylinders and rectangular prisms in polymer solutions of different measure of shear thinning and elasticity has been measured. 相似文献
4.
5.
Jiři Gregor 《Mathematics of Control, Signals, and Systems (MCSS)》1991,4(2):205-215
A significant part of the theory of one-dimensional linear shift-invariant systems is based on the concept of weighting function
(or impulse response): the output is the convolution of the weighting function with the input. This paper introduces the concept
of linear translation-invariant systems and uses this notion in studying impulse response, z-transforms, and transfer functions
for multidimensional systems. 相似文献
6.
Jiří Polívka 《Journal of Infrared, Millimeter and Terahertz Waves》1996,17(10):1779-1788
In his earlier paper on Active Microwave Radiometry, the author indicated that microwave noise can be used to map field density distribution inside radiators and in antenna systems, without the need for anechoic chambers. The presented paper gives details and results of such experiment. The method is described, details of equipment are given and results are presented with a concluding commentary. 相似文献
7.
The hydroxycarbonate of nickel and aluminium (Ni/ Al = 3) with a hydrotalcite-like structure is an outstanding precursor of the active component of supported nickel catalysts. Good mechanical strength and suitable nickel content of these catalysts, which are necessary for practical applications, can be achieved by mechanical mixing of this compound with an additional support. The catalyst prepared from a mixture of 56.5 wt-% of nickel-aluminium hydroxycarbonate and 43.5 wt-% of γ-alumina was proven to have a stable catalytic activity in the methanation reaction at 2 MPa and 800 K. 相似文献
8.
M. Kohl M. Odehnal V. Petříěek R. Tichý S. Šafrata 《Journal of Low Temperature Physics》1988,72(3-4):319-343
We describe an apparatus allowing the observation of the NMR static longitudinal component of nuclear magnetizationM
z
by a SQUID at low magnetic fields and atT=4.2 K in Plexiglas, Teflon, and CaF2. The higher order NMR Larmor lines at 2f
0, 3f
0, and 4f
0, wheref
0 is the Larmor frequency of the allowed NMR line, were measured. These lines correspond to a flip of two, three, and four spins, respectively, by one photon. The amplitudes of 2f
0 and 3f
0 lines and their field dependences show that the common assertion that the forbidden lines at 2f
0 and 3f
0 appear in the same order of perturbation theory and that their intensity decreases with static magnetic fieldB
0 asB
0
–2
is wrong. In fact, the third Larmor line 3f
0 appears at higher order than the second Larmor line 2f
0 and its intensity decreases asB
0
–4
. This is also shown by a theoretical calculation of its intensity. For the first time the NMR SQUID technique allowed the detection of the 4f
0 line, corresponding to the simultaneous flip of four spins by one photon. 相似文献
9.
Summary The effect of tert-butyl chloride in the polymerizations of isobutylene carried out in the presence of SnCl4 in dichloromethane at temperatures-20°C and-78°C was investigated. Synthesized polyisobutylene samples showed a bimodal molecular
weight distribution (MWD) and it was found that the weight content of the lowermolecular weight (LMW) fraction increased with
increasing t-BuCl concentration in the polymerization mixture. The effect of ageing of the initiation mixture t-BuCl/SnCl4 in CH2Cl2 prepared in advance on MWD of the PIB samples was also studied. Ageing of the initiation system supports the formation of
the LMW fraction and this oily PIB is the only product of the polymerization at-20°C,
. 相似文献
10.
The paper deals with state estimation of the nonlinear stochastic systems by means of the unscented Kalman filter with a focus on specification of the σ-points. Their position is influenced by two design parameters—the scaling parameter determining the spread of the σ-points and a covariance matrix decomposition determining rotation of the σ-points. In this paper, a choice of the scaling parameter is analyzed. It is shown that considering other values than the standard choice may lead to increased quality of the estimate, especially if the scaling parameter is adapted. Several different criteria for the adaptation are proposed and techniques to reduce computational costs of the adaptation are developed. The proposed algorithm of the unscented Kalman filter with advanced adaptation of the scaling parameter is illustrated in a numerical example. 相似文献