全文获取类型
收费全文 | 79399篇 |
免费 | 16705篇 |
国内免费 | 732篇 |
专业分类
电工技术 | 2017篇 |
技术理论 | 3篇 |
综合类 | 1268篇 |
化学工业 | 25480篇 |
金属工艺 | 2236篇 |
机械仪表 | 3363篇 |
建筑科学 | 3690篇 |
矿业工程 | 438篇 |
能源动力 | 2295篇 |
轻工业 | 10195篇 |
水利工程 | 699篇 |
石油天然气 | 1119篇 |
武器工业 | 155篇 |
无线电 | 12088篇 |
一般工业技术 | 18531篇 |
冶金工业 | 3498篇 |
原子能技术 | 584篇 |
自动化技术 | 9177篇 |
出版年
2024年 | 98篇 |
2023年 | 579篇 |
2022年 | 882篇 |
2021年 | 1491篇 |
2020年 | 2341篇 |
2019年 | 3940篇 |
2018年 | 4093篇 |
2017年 | 4480篇 |
2016年 | 4935篇 |
2015年 | 5041篇 |
2014年 | 5473篇 |
2013年 | 7303篇 |
2012年 | 5257篇 |
2011年 | 5380篇 |
2010年 | 4939篇 |
2009年 | 4817篇 |
2008年 | 4349篇 |
2007年 | 3876篇 |
2006年 | 3586篇 |
2005年 | 3166篇 |
2004年 | 2637篇 |
2003年 | 2541篇 |
2002年 | 2421篇 |
2001年 | 2129篇 |
2000年 | 2157篇 |
1999年 | 1627篇 |
1998年 | 1460篇 |
1997年 | 1085篇 |
1996年 | 963篇 |
1995年 | 771篇 |
1994年 | 533篇 |
1993年 | 442篇 |
1992年 | 348篇 |
1991年 | 299篇 |
1990年 | 235篇 |
1989年 | 217篇 |
1988年 | 179篇 |
1987年 | 119篇 |
1986年 | 110篇 |
1985年 | 94篇 |
1984年 | 59篇 |
1983年 | 42篇 |
1982年 | 47篇 |
1981年 | 45篇 |
1980年 | 45篇 |
1979年 | 22篇 |
1977年 | 32篇 |
1976年 | 47篇 |
1975年 | 23篇 |
1974年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Hwang Seongil Park Sang Hyun Jin Maolin Kang Sang Hoon 《Intelligent Service Robotics》2021,14(3):471-484
Intelligent Service Robotics - A robust control designed for multiple degrees-of-freedom (DOF) robot manipulators performing complex tasks requiring frequent physical interaction with unknown... 相似文献
92.
High‐performance thermosets with tailored properties derived from methacrylated eugenol and epoxy‐based vinyl ester 下载免费PDF全文
Yuehong Zhang Yuzhan Li Vijay Kumar Thakur Zhenhua Gao Jiyou Gu Michael R Kessler 《Polymer International》2018,67(5):544-549
A renewable chemical, eugenol, is methacrylated to produce methacrylated eugenol (ME) employing the Steglich esterification reaction without any solvent. The resulting ME is used as a low‐viscosity co‐monomer to replace styrene in a commercial epoxy‐based vinyl ester resin (VE). The volatility and viscosity of ME and styrene are compared. The effect of ME loading and temperature on the viscosity of the VE–ME resin is investigated. Moreover, the thermomechanical properties, curing extent and thermal stability of the fully cured VE–ME thermosets are systematically examined. The results indicate that ME is a monomer with low volatility and low viscosity, and therefore the incorporation of ME monomer in VE resins allows significant reduction of viscosity. Moreover, the viscosity of the VE–ME resin can be tailored by adjusting the ME loadings and processing temperature to meet commercial liquid molding technology requirements. The glass transition temperatures of VE–ME thermosets range from 139 to 199 °C. In addition, more than 95% of the monomer is incorporated and fixed in the crosslinked network structure of VE–ME thermosets. Overall, the developed ME monomer exhibits promising potential for replacing styrene as an effective low‐viscosity co‐monomer. The VE–ME resins show great advantages for use in polymer matrices for high‐performance fiber‐reinforced composites. This work is of great significance to the vinyl ester industry by providing detailed experimental support. © 2018 Society of Chemical Industry 相似文献
93.
94.
Application of high‐temperature Fenton oxidation for the treatment of sulfonation plant wastewater 下载免费PDF全文
95.
This paper considers a novel distributed iterative learning consensus control algorithm based on neural networks for the control of heterogeneous nonlinear multiagent systems. The system's unknown nonlinear function is approximated by suitable neural networks; the approximation error is countered by a robust term in the control. Two types of control algorithms, both of which utilize distributed learning laws, are provided to achieve consensus. In the provided control algorithms, the desired reference is considered to be an unknown factor and then estimated using the associated learning laws. The consensus convergence is proven by the composite energy function method. A numerical simulation is ultimately presented to demonstrate the efficacy of the proposed control schemes. 相似文献
96.
Han Yan Gu Yi Chen Lei Li Bing Liu Xiang Ming Chen 《International Journal of Applied Ceramic Technology》2020,17(2):790-796
SrLa[Ga1−x(R0.5Ti0.5)x]O4 (R = Mg, Zn) ceramics were prepared by a standard solid state sintering method. The single-phase ceramics with K2NiF4-type layered perovskite structure and I4/mmm space group were obtained, indicating that SrLa(R0.5Ti0.5) and SrLaGaO4 can form the unlimited solid solutions. With increasing x for R = Mg and Zn, εr increases monotonously, the Qf value first increases and then decreases, while τf increases from a negative to a positive value. The optimized microwave dielectric properties were obtained as following: εr = 23.3, Qf = 89 400 GHz, τf = −0.8 ppm/°C for SrLa[Ga0.6(Mg0.5Ti0.5)0.4]O4 and εr = 23.3, Qf = 76 200 GHz, τf = 0.2 ppm/°C for SrLa[Ga0.7(Zn0.5Ti0.5)0.3]O4, indicating that the present solid solution ceramics are the promising candidates as microwave resonator materials for the telecommunication applications. 相似文献
97.
98.
99.
Ricardo Cambraia Parreira Diana Paola Gmez‐Mendoza Itamar Couto Guedes de Jesus Rafael Pereira Lemos Anderson Kennedy Santos Cristiana Perdigo Rezende Henrique Csar Pereira Figueiredo Mauro Cunha Xavier Pinto Frank Kjeldsen Silvia Guatimosim Rodrigo Ribeiro Resende Thiago Verano‐Braga 《Proteomics. Clinical applications》2020,14(4)
100.
The application of deep learning in the field of object detection has
experienced much progress. However, due to the domain shift problem, applying an
off-the-shelf detector to another domain leads to a significant performance drop. A
large number of ground truth labels are required when using another domain to train
models, demanding a large amount of human and financial resources. In order to avoid
excessive resource requirements and performance drop caused by domain shift, this
paper proposes a new domain adaptive approach to cross-domain vehicle detection. Our
approach improves the cross-domain vehicle detection model from image space and
feature space. We employ objectives of the generative adversarial network and cycle
consistency loss for image style transfer in image space. For feature space, we align
feature distributions between the source domain and the target domain to improve the
detection accuracy. Experiments are carried out using the method with two different
datasets, proving that this technique effectively improves the accuracy of vehicle
detection in the target domain. 相似文献