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71.
Nitrous oxide produced a dose-related "analgesia" in mice (median effective dose, 55 percent). The analgesia was evaluated by means of a phenylquinone writhing test. Narcotic antagonists or chronic morphinization reduced nitrous oxide analgesia. Either nitrous oxide releases an endogenous analgesic or narcotic antagonists have analgesic antagonist properties heretofore unappreciated. 相似文献
72.
Summary A constitutive model is derived for the elastic behavior of rubbers at three-dimensional deformations with finite strains.
An elastomer is thought of as an incompressible network of flexible chains bridged by permanent junctions that move affinely
with the bulk medium. The constraints imposed by surrounding macromolecules on configurations of an individual chain are introduced
by combining the Flory–Erman and Erman–Monnerie approaches. To describe inter-chain interactions in a tractable way, the conventional
picture of a tube where a chain is confined is replaced by geometrical restrictions on the positions of its ends and center
of mass. The constraints on the chain ends are formulated within the traditional Flory concept, whereas those on the position
of center of mass are described following the Ronca–Allegra scenario. Stress–strain relations for a network of constrained
chains are derived by using the laws of thermodynamics. The constitutive equations involve four adjustable parameters with
transparent physical meaning. The material constants are found by fitting experimental data on elastomers at uniaxial and
equi-biaxial tensions and pure shear. It is demonstrated that (i) the model provides an acceptable prediction of stresses
in a test with one deformation mode, when its parameters are found by matching observations in an experiment with another
mode, and (ii) material constants are affected by chemical composition of elastomers in a physically plausible way. 相似文献
73.
气动上下料机械手手部结构的设计与分析 总被引:6,自引:0,他引:6
以炮弹径长自动检测生产线上搬运炮弹机械手的手部结构为研究对象,采用单片机对其气压驱动装置进行顺序控制,为保证结构设计的合理性,在论述系统组成、机械手运动、坐标形式及运动范围的基础上,运用有限元分析方法对手部结构进行分析和优化改进,结构设计满足验算结果要求. 相似文献
74.
Wafer Direct Bonding: From Advanced Substrate Engineering to Future Applications in Micro/Nanoelectronics 总被引:3,自引:0,他引:3
Christiansen S.H. Singh R. Gosele U. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2006,94(12):2060-2106
Wafer direct bonding refers to the process of adhesion of two flat mirror-polished wafers without using any intermediate gluing layers in ambient air or vacuum at room temperature. The adhesion of the two wafers occurs due to attractive long range van der Waals or hydrogen bonding forces. At room temperature the bonding energy of the interface is low and higher temperature annealing of the bonded wafer pairs has to be carried out to enhance the bonding energy. In this paper, we describe the prerequisites for the wafer-bonding process to occur and the methods to prepare the suitable surfaces for wafer bonding. The characterization techniques to assess the quality of the bonded interfaces and to measure the bonding energy are presented. Next, the applications of wafer direct bonding in the fabrication of novel engineered substrates such as "silicon-on-insulator" and other "on-insulator" substrates are detailed. These novel substrates, often called hybrid substrates, are fabricated using wafer bonding and layer splitting via a high dose hydrogen/helium implantation and subsequent annealing. The specifics of this process, also known as the smart-cut process, are introduced. Finally, the role of wafer bonding in future nanotechnology applications such as nanotransistor fabrication, three-dimensional integration for high-performance micro/nanoelectronics, nanotemplates based on twist bonding, and nano-electro-mechanical systems is discussed 相似文献
75.
Peng ZHANG Yunhui DU Hanwu LIU Daben ZENG Jianzhong CUI Limin BA Department of Mechanical Engineering Beijing Jiaotong University Beijing China Department of Mechanical Engineering Tsinghua University Beijing China Metal Forming Department Northeastern University Shenyang China Anshan Automobile Fittings Factory Anshan China 《材料科学技术学报》2005,21(4):589-592
The rolling treatment of steel-mushy QTi3.5-3.5 graphite composite was conducted under different relative reduction at room temperature. The effect of room-temperature rolling on interfacial mechanical property of steel-mushy QTi3.5-3.5 graphite composite was studied and the relationship between interfacial shear strength and relative reduction was established. The results show that, for steel-mushy QTi3.5-3.5 graphite composite, which consists of 1.2 mm-thick 08AI steel plate and 2.8 mm-thick QTi3.5-3.5 graphite layer, there is a nonlinear relationship between interfacial shear strength and relative reduction in graphite layer. When relative reduction is smaller than 1.1%, interfacial shear strength increases with increasing the relative reduction. When relative reduction is larger than 1.1%, interfacial shear strength decreases with increasing the relative reduction. When relative reduction is 1.1%, the largest interfacial shear strength of 145.2 MPa can be obtained. 相似文献
76.
SLE 4442 逻辑加密存储卡的加密机制依赖的只是保存在IC卡中的几位固定数字组成的卡密码,其抗破译和窃取的能力与应用系统的安全设计有着非常紧密的关系,本文以SLE4442 IC卡为具体研究对象,通过对其安全性进行分析,采用DES加密算法,系统全面地设计了一种逻辑加密卡安全应用体系,并将其应用在IC卡自动加油机控制系统中。 相似文献
77.
巴政 《河南纺织高等专科学校学报》2003,15(3):33-35
介绍了USB技术的基本特点、传送方式和应用优势,并且简要说明USB技术在工业测控中的引入原因、应用思路和前景。 相似文献
78.
阐述了电容式电压互感器的各种阻尼器的优缺点,并对速饱和阻尼器设计进行了详述,提出了CVT设计速饱和阻尼器应注意的事项。 相似文献
79.
80.