全文获取类型
收费全文 | 239716篇 |
免费 | 14276篇 |
国内免费 | 7227篇 |
专业分类
电工技术 | 10171篇 |
技术理论 | 9篇 |
综合类 | 11984篇 |
化学工业 | 38337篇 |
金属工艺 | 13452篇 |
机械仪表 | 12942篇 |
建筑科学 | 14585篇 |
矿业工程 | 5209篇 |
能源动力 | 5742篇 |
轻工业 | 13770篇 |
水利工程 | 3943篇 |
石油天然气 | 9913篇 |
武器工业 | 1203篇 |
无线电 | 27194篇 |
一般工业技术 | 35361篇 |
冶金工业 | 10400篇 |
原子能技术 | 1985篇 |
自动化技术 | 45019篇 |
出版年
2024年 | 778篇 |
2023年 | 2801篇 |
2022年 | 4894篇 |
2021年 | 6852篇 |
2020年 | 5168篇 |
2019年 | 4458篇 |
2018年 | 18495篇 |
2017年 | 18085篇 |
2016年 | 14137篇 |
2015年 | 7022篇 |
2014年 | 8034篇 |
2013年 | 9471篇 |
2012年 | 13010篇 |
2011年 | 19963篇 |
2010年 | 17239篇 |
2009年 | 14226篇 |
2008年 | 15245篇 |
2007年 | 15675篇 |
2006年 | 8621篇 |
2005年 | 8406篇 |
2004年 | 6109篇 |
2003年 | 5557篇 |
2002年 | 4669篇 |
2001年 | 3846篇 |
2000年 | 4030篇 |
1999年 | 4171篇 |
1998年 | 3522篇 |
1997年 | 2973篇 |
1996年 | 2739篇 |
1995年 | 2338篇 |
1994年 | 1873篇 |
1993年 | 1327篇 |
1992年 | 1089篇 |
1991年 | 893篇 |
1990年 | 650篇 |
1989年 | 584篇 |
1988年 | 455篇 |
1987年 | 326篇 |
1986年 | 219篇 |
1985年 | 145篇 |
1984年 | 101篇 |
1983年 | 86篇 |
1982年 | 90篇 |
1981年 | 60篇 |
1980年 | 61篇 |
1968年 | 43篇 |
1966年 | 43篇 |
1965年 | 47篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Mei Xuan Xu Wen Guang Liu Yun Lin Guan Zuo Peng Bi Kang De Yao 《Polymer International》1995,38(2):205-209
The phase behavior of a hybrid polymer network (HPN) composed of poly[(propylene glycol maleate)-co-(propylene glycol phthalate)] crosslinked with styrene and polyester–urethane crosslinked with methylene-bis-ortho-chloroaniline was examined. The correlation between phase separation and impact strength of the HPNs is discussed. The composition of HPNs has an effect on their properties. 相似文献
93.
Ivan Cimrák 《Archives of Computational Methods in Engineering》2007,15(3):277-309
The Landau-Lifshitz (LL)equation of micromagnetism governs rich variety of the evolution of magnetization patterns in ferromagnetic
media. This is due to the complexity of physical quantities appearing in the LL equation. This complexity causes also an interesting
mathematical properties of the LL equation: nonlocal character for some quantities,nonconvex side-constraints, strongly nonlinear
terms. These effects influence also the numerical approximations. In this work, recent developments on the approximation of
weak solutions, together with the overview of well-known methods for strong solutions,are addressed.
Author is supported by the Fund for Scientific Research - Flanders FWO (Belgium). 相似文献
94.
95.
The Uniform Geometrical Theory of Diffraction (UTD) has been successfully used in pattern analysis of airborne dipole antenna on the A-5 fighter in high-frequency region. In the analysis, several canonical problems are investigated first, then the complicated problem is calculated with compiling these canonical problems. The numerical results are compared with the experimental data, and good agreement has been seen. The effectiveness and practicality of the present analysis are thus verified. 相似文献
96.
Bugong Xu 《Automatic Control, IEEE Transactions on》1995,40(5):930-933
A new criterion for delay-independent stability of linear large scale time-delay systems is deduced by employing an improved Razumikhin-type theorem and the m-matrix properties. An illustrative example is given to demonstrate the superiority of the obtained results to those in the literature 相似文献
97.
98.
Xiao Sun Chow M.H.L. Leung F.H.F. Dehong Xu Yousheng Wang Yim-Shu Lee 《Power Electronics, IEEE Transactions on》2002,17(3):305-313
An analogue neural-network controller for UPS inverter applications is presented. The proposed neural-network controller is trained off-line using patterns obtained from a simulated controller, which had an idealized load-current-reference. Simulation results show that the proposed neural-network controller can achieve low total harmonic distortion under nonlinear loading condition and good dynamic responses under transient loading condition. To verify the performance of the proposed NN controller, a hardware inverter with an analogue neural network (NN) controller (using mainly operational amplifiers and resistors) is built. Additionally, for comparison purposes, a PI controller with optimized parameters is built. Experimental results confirm the simulation results and show the superior performance of the NN controller especially under rectifier-type loading condition. Implementing the analogue neural-network controller using programmable integrated circuits is also discussed 相似文献
99.
Herein, we report an efficient process for preparing monodisperse Au@SiO2 nanoparticles using homogeneous shaking and without the use of surface‐coupling silane agents or large stabilizers. The resulting pure‐silica surface of the Au@SiO2 nanoparticles is very important for straightforward surface functionalization with different functional groups via well‐established silica surface chemistry. Subsequent covalent bioconjugation of the aldehyde‐functionalized Au@SiO2 nanoparticles with various biomolecules is successfully employed to make robust nanoprobes for fast, colorimetric DNA and protein detection based on the sequence‐specific hybridization properties of DNA and the specific binding affinity between proteins, respectively. 相似文献
100.