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61.
本文在数字显示卡尺技术和力矩电机技术的基础上,把卡尺量程扩大到20米做成卡卷尺,运用力矩电机作为卡卷尺的卷紧机构和保证光栅编码器标尺光栅平直度的施力元件,发展了力矩电机自动调节的大量程数字显示卡卷尺测长技术,同时为力矩电机设计了线性自动调节电流源,并在实际应用中检测了其测量精确度。 相似文献
62.
文章提出一个完整的系统,将多声部乐谱原文转换成可编辑乐谱文本。系统首先在乐符检测阶段将图象切分为谱表,然后再其切分成个别对象。 相似文献
63.
Following the study of migration processes in the continuous domain in Part I of this paper, we reformulate the concept of migration in the discrete domain (Zm) and define Discrete Migration Processes (DMP). We demonstrate that this model is a natural discrete representation of the continuous model and maintains the model's features in a qualitative sense. We show that under discrete migration any discrete set shrinks to a limit in finitely many iterations. The discrete representation provides an advantageous basis for digitally implementing the MP model. Using this implementation we illustrate the discrete migration of various types of sets under various types of constraints. 相似文献
64.
65.
四层应用软件系统的分析与开发 总被引:3,自引:0,他引:3
从软件工程的角度提出了传统三层结构的应用软件系统的不足,分析了四层结构的应用软件系统架构.分别对三层与四层应用软件系统中的业务逻辑处理进行分析和对比,从而得出四层架构较传统的三层架构的优势所在,并在.net平台下,开发出一个四层结构的真实应用软件系统. 相似文献
66.
基于文本挖掘的搭配词典自动架构探讨 总被引:2,自引:0,他引:2
研究词语搭配的关系对于自然语言处理有很大的帮助。目前对计算机用的搭配词典是用人工方法实现的,它由人工进行维护,有更新慢、收藏的词少等缺点。为此,利用文本挖掘技术对大规模语料库进行分析,挖掘词语搭配的深层关系,在此基础上自动建立词语搭配词典,实验结果显示该方法是有效的。 相似文献
67.
Continuous cast (CC) AA5182 Al alloy with the precipitation of Mg2Al3 and of MnAl6 was cold rolled to 70% reduction and then isothermally annealed in a salt bath at three temperatures (316, 343, and 371 °C) for different times. Texture evolution during recrystallization was investigated. It was found that the recrystallization textures of the material with intense Mg2Al3 precipitation along the grain boundaries exhibited weaker Cube, Goss and R/β fiber components than those of the material with the more uniform fine MnAl6 precipitates. The opposite was true in the cold rolled condition, i.e. the material with MnAl6 precipitation had weaker Cube, Goss, and R/β fiber components in the cold rolled condition than the material with intense Mg2Al3 precipitation. Thus, recrystallization textures of material with Mg2Al3 precipitation were weaker than material with MnAl6 precipitation. This is due to the fact that large Mg2Al3 particles favor the nucleation of randomly oriented grains. When subjected to formability tests, the material with prior Mg2Al3 precipitation displayed a lower anisotropy in tensile yield strength, ultimate tensile strength, elongation, and strain hardening exponent than material with prior MnAl6 precipitation. This is in accord with the texture results which indicated that the recrystallization textures of material with an initial Mg2Al3 precipitation were closer to those of a perfectly random sample than those of material with an initial MnAl6 precipitation. On the other hand, the elongation and Olsen values were lower and the surface quality after bending tests was worse for material with Mg2Al3 precipitation. This is due to the non-uniform distribution of Mg2Al3 particles which precipitated primarily along the grain boundaries and caused an earlier formation and coalescence of the microvoids around the grain boundary precipitates. The forming limit diagrams (FLD) correlated well with the tensile, Olsen and bending results. 相似文献
68.
Shanwu Yang Enlong Dong Huibin Wu Chengjia Shang Xuemin Wang Xinlai He 《北京科技大学学报(英文版)》2005,12(4):317-320
Cooled in water after the isothermal relaxation of deformed austenite for different timea, a Nb-bearing microalloyed steel always exhibits synthetic microstructures of bainitic ferrite, granular bainite and acicular ferrite. When these samples were reheated to and held at 650 or 700℃, the non-equilibrious microstructures tend to evolve into equilibrious ones. The sample relaxed for 60 s displays the highest thermostability, while the microstructure evolution is the quickest in the sample relaxed for 1000 s even though it is the softest before reheating. Softening is not a single process occurring during reheating, in which the hardness fluctuates with time. There are two peaks in the hardness-time curve of each sample having undergone relaxation, while a single peak occurs in the curve of the sample having not been relaxed. Pre-strain accelerates the evolution process. These results indicate that the thermostability of microstructures is determined by their history of formation to a considerable degree. 相似文献
69.
水泥砂浆的率型损伤演化 总被引:5,自引:0,他引:5
实验结果表明,水泥砂浆在受力变形中的损伤演化是率相关的,因此,类似于位错运动的热激活机制;给出了水泥砂浆的率型损伤演化律. 相似文献
70.
夹杂物问题应力场的数值计算 总被引:3,自引:1,他引:3
等效夹杂物方法是细观力学中的一种重要方法,文中编制的数值计算程序能在考虑多个夹杂物相互响应的情况下计算材料应力、应变场,并实现了计算结果的三维显示.计算结果与文献中的计算结果非常吻合.本文编制的数值计算程序不仅可以用于研究复合材料的损伤演化及失效,而且利用特殊构型的椭球空洞来模拟裂纹,可以计算裂纹群的应力、应变场。 相似文献