全文获取类型
收费全文 | 11164篇 |
免费 | 68篇 |
国内免费 | 140篇 |
专业分类
电工技术 | 135篇 |
综合类 | 2篇 |
化学工业 | 458篇 |
金属工艺 | 460篇 |
机械仪表 | 57篇 |
建筑科学 | 79篇 |
矿业工程 | 2篇 |
能源动力 | 51篇 |
轻工业 | 133篇 |
水利工程 | 25篇 |
石油天然气 | 8篇 |
无线电 | 417篇 |
一般工业技术 | 339篇 |
冶金工业 | 232篇 |
原子能技术 | 99篇 |
自动化技术 | 8875篇 |
出版年
2022年 | 19篇 |
2021年 | 42篇 |
2020年 | 23篇 |
2019年 | 31篇 |
2018年 | 32篇 |
2017年 | 18篇 |
2016年 | 27篇 |
2015年 | 17篇 |
2014年 | 249篇 |
2013年 | 227篇 |
2012年 | 819篇 |
2011年 | 3119篇 |
2010年 | 1171篇 |
2009年 | 1033篇 |
2008年 | 703篇 |
2007年 | 616篇 |
2006年 | 478篇 |
2005年 | 603篇 |
2004年 | 546篇 |
2003年 | 599篇 |
2002年 | 291篇 |
2001年 | 20篇 |
2000年 | 24篇 |
1999年 | 38篇 |
1998年 | 145篇 |
1997年 | 56篇 |
1996年 | 47篇 |
1995年 | 30篇 |
1994年 | 20篇 |
1993年 | 24篇 |
1992年 | 20篇 |
1991年 | 21篇 |
1990年 | 19篇 |
1989年 | 12篇 |
1988年 | 14篇 |
1987年 | 16篇 |
1986年 | 25篇 |
1985年 | 16篇 |
1984年 | 33篇 |
1983年 | 21篇 |
1982年 | 15篇 |
1981年 | 17篇 |
1980年 | 16篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1968年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
1.
2.
3.
4.
5.
Navab SinghAuthor Vitae Moitreyee Mukherjee-RoyAuthor VitaeSohan Singh MehtaAuthor Vitae 《Microelectronics Journal》2003,34(4):237-245
The patterning of contact holes by selecting out-of-focus image plane (defocus) using attenuated phase shift masks (APSM) has been studied. Defocus is found to enhance the image modulation at low partial coherence for contact holes with negative local average of mask function. Semi-dense holes up to 130 nm in 8% APSM have been printed by 0.5 μm defocus at a partial coherence of 0.31 using KrF scanner with highest numerical aperture of 0.68. However, these holes were closed with in-focus imaging. Defocus is also found to be beneficial for patterning the pitches that have extensive side lobes with in-focus imaging. 相似文献
6.
7.
H Neudeck M Joncic C Schuster S Bisson R Hildebrandt T Oney B Stiemer H Hopp R Graf 《Canadian Metallurgical Quarterly》1997,37(6):449-458
Nitric oxide (NO) acts as a modulator of neuronal transmission in mature neuronal systems, including the retina. Recently, NO has also been suggested to have a trophic function during development. We examined immunocytochemically the distribution of NO-producing cells in developing and transplanted rabbit retinas. An antibody detecting the neuronal isoform of its biosynthetic enzyme, nitric oxide synthase (NOS), was used on normal developing retinas [starting at embryonic day (E) 15] and on rabbit retinal transplants after various survival times (1-139 days after surgery). Weakly stained cell bodies were first observed in the proximal margin of the neuroblastic layer at E 29. Stained processes projecting towards a developing inner plexiform layer were also visible at this time point. Immunoreactive cells were located at later stages in the innermost part of the inner nuclear layer and in the ganglion cell layer, and are likely to correspond mainly to amacrine cells. NOS-labelled cells were also found in retinal transplants. The first NOS-labelled cells appeared, as in normal developing retinas, in ages corresponding to E 29 and were still detected in transplants corresponding to postnatal day 123. NOS-labelled cells were seen in areas between rosettes, where amacrine cells are located. NOS-labelled processes were at times seen to project for long distances, forming very distinct plexuses. NOS-containing amacrine cells thus appear both in the transplants and in developing retinas in the embryonic stages, long before synaptic function involving these cells can be expected, suggesting a role for NO not only in neuromodulation but also in retinal development. 相似文献
8.
Adaptive motion control using neural network approximations 总被引:1,自引:0,他引:1
In this paper, we present a new adaptive technique for tracking control of mechanical systems in the presence of friction and periodic disturbances. Radial Basis Functions (RBFs) are used to compensate for the effects of nonlinearly occurring parameters in the friction and periodic disturbance model. Theoretical analysis, such as stability and transient performance, is provided. Furthermore, the performance of the adaptive RBF controller and its non-adaptive counterpart are compared. 相似文献
9.
Cherng-Min MaAuthor Vitae 《Pattern recognition》2003,36(8):1775-1782
Generally, a reduction operation (e.g., thinning and shrinking) on 3D binary images can be represented as a set of reduction templates where every object voxel of the image satisfying any template is turned to a background voxel. Generally, it is rather difficult, error-prone and time-consuming for verifying the topological soundness of a 3D parallel reduction operation. This paper proposes sufficient conditions of time complexity O(n) for verifying the topological soundness of 3D parallel 6-subiteration reduction operations of n templates where such a kind of 3D reduction operations is performed alternatively from the six orthogonal directions to turn object voxels to background voxels. By such sufficient conditions, the topology soundness of a 3D 6-subiteration parallel reduction operation can be verified by checking each and every of its templates. 相似文献
10.
In this paper, we present a control methodology for a class of discrete time nonlinear systems that depend on a possibly exogenous scheduling variable. This class of systems consists of an interpolation of nonlinear dynamic equations in strict feedback form, and it may represent systems with a time-varying nonlinear structure. Moreover, this class of systems is able to represent some cases of gain scheduling control, Takagi-Sugeno fuzzy systems, as well as input-output realizations of nonlinear systems which are approximated via localized linearizations. We present two control theorems, one using what we call a “global” approach (akin to traditional backstepping), and a “local” approach, our main result, where backstepping is again used but the control law is an interpolation of local control terms. An aircraft wing rock regulation problem with varying angle of attack is used to illustrate and compare the two approaches. 相似文献