全文获取类型
收费全文 | 12828篇 |
免费 | 618篇 |
国内免费 | 16篇 |
专业分类
电工技术 | 174篇 |
综合类 | 9篇 |
化学工业 | 3435篇 |
金属工艺 | 240篇 |
机械仪表 | 336篇 |
建筑科学 | 529篇 |
矿业工程 | 20篇 |
能源动力 | 460篇 |
轻工业 | 1575篇 |
水利工程 | 79篇 |
石油天然气 | 50篇 |
无线电 | 1070篇 |
一般工业技术 | 2198篇 |
冶金工业 | 1091篇 |
原子能技术 | 126篇 |
自动化技术 | 2070篇 |
出版年
2023年 | 97篇 |
2022年 | 343篇 |
2021年 | 455篇 |
2020年 | 256篇 |
2019年 | 319篇 |
2018年 | 386篇 |
2017年 | 394篇 |
2016年 | 464篇 |
2015年 | 319篇 |
2014年 | 458篇 |
2013年 | 809篇 |
2012年 | 720篇 |
2011年 | 843篇 |
2010年 | 626篇 |
2009年 | 679篇 |
2008年 | 612篇 |
2007年 | 582篇 |
2006年 | 542篇 |
2005年 | 417篇 |
2004年 | 357篇 |
2003年 | 312篇 |
2002年 | 280篇 |
2001年 | 224篇 |
2000年 | 194篇 |
1999年 | 188篇 |
1998年 | 321篇 |
1997年 | 259篇 |
1996年 | 206篇 |
1995年 | 185篇 |
1994年 | 151篇 |
1993年 | 145篇 |
1992年 | 81篇 |
1991年 | 71篇 |
1990年 | 81篇 |
1989年 | 69篇 |
1988年 | 82篇 |
1987年 | 62篇 |
1986年 | 45篇 |
1985年 | 96篇 |
1984年 | 71篇 |
1983年 | 62篇 |
1982年 | 62篇 |
1981年 | 93篇 |
1980年 | 54篇 |
1979年 | 61篇 |
1977年 | 45篇 |
1976年 | 59篇 |
1975年 | 42篇 |
1974年 | 34篇 |
1973年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
We present a general method and a toolkit for designing, implementing and visualizing distributed algorithms. We make use of the high level encoding of distributed algorithms as graph rewriting systems. The result is a unified and simple framework for describing, implementing and visualizing a large family of distributed algorithms. 相似文献
32.
Loranger Michel; Pépin Michel; Gignac Guy; Benoit Geneviève 《Canadian Metallurgical Quarterly》1995,36(1):59
Presents results of 3 studies on the psychometric properties of the LP-ABC (M. Loranger and M. Pépin, 1993), a French-language instrument for assessing general functioning in adults with mental retardation. The studies involved a total of 299 male and female Canadian adults with mental retardation. Results confirm the internal consistency, construct validity, criterion validity, discriminant validity, interrater reliability, and test–retest reliability of the LP-ABC. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
Due to the increasing penetration of wind energy, it is necessary to possess design tools that are able to simulate the impact of these installations on electric utility grids. In order to provide a net contribution to this issue, a detailed wind park model has been developed and is briefly presented. However, the computational costs associated with the performance of such a detailed model in describing the behavior of a wind park composed by a considerable number of units may render its practical application very difficult. To overcome this problem, singular perturbations theory has been applied to reduce the order of the detailed wind park model, and therefore create the conditions for the development of a dynamic equivalent which is able to retain the relevant dynamics with respect to the existing AC power system. Validation results proving the ability of singular perturbations reduced order model to match the results provided by the detailed model are shown and commented upon 相似文献
34.
The present work shows that laser surface alloying of the creviced area on Al 7175-T7351 with chromium can avoid crevice corrosion. Corrosion takes places outside the crevice in conditions where the ratio of anodic area to cathodic area is favourable to minimize corrosion. As laser surface processing is adequate for treating small areas there is an enormous potential in this technology. 相似文献
35.
Emmanuel. Delamarche Bruno. Michel Hans A. Biebuyck Christoph Gerber 《Advanced materials (Deerfield Beach, Fla.)》1996,8(9):719-729
Self-assembled monolayers (SAMs) of alkanethiols and disulfides on gold form organic interfaces with properties largely controlled by the end groups of the molecules composing the film. SAMs provide a unique link between the science of organic surfaces and technologies that seek to exploit their adaptable character. Many techniques are useful for probing the structure of SAMs although only scanning tunneling microscopy (STM) at picoamperes reveals the details of the packing of their end groups at the sub-angstrom level. This review demonstrates that STM effectively tests new types of control over the microscopic structure–property relationships characteristic of SAMs on gold that should prove useful to their application. 相似文献
36.
37.
Ferdinand P. Ferragu O. Lechien J.L. Lescop B. Magne S. Marty V. Rougeault S. Kotrotsios G. Neuman V. Depeursinge Y. Michel J.B. Van Uffelen M. Varelas D. Berthou H. Pierre G. Renouf C. Jarret B. Verbandt Y. Stevens W. Voet M.R.H. Toscano D. 《Lightwave Technology, Journal of》1995,13(7):1303-1313
Recent developments of stability control in mines, essentially based on Ge-doped fiber Bragg gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, sensor network topology and multiplexing method, user interface design and sensor packaging 相似文献
38.
This article is primarily concerned with standards seen as a means for collective appropriation of technological information. It begins with an attempt to throw light on the relationships between standards, patents and licenses. Then we develop a two-stage duopolistic model whereby each firm must decide on a programme of standardization before choosing its level of production. The risks of multiple or inefficient equilibria are strong enough to justify the intervention of standardization organizations to inform and coordinate individual firms. But the paper also explains why some organizations likeetsi try to play a new role by promoting open access to master patents when used in the definition of a standard. 相似文献
39.
Muon spin relaxation measurements were carried out in zero magnetic field on amorphous Hf2Co. The results obtained and comparison with the behaviour of the muon in crystalline Hf2Co (A. Baudry, P. Boyer, L.P. Ferreira, S.W. Harris, S. Miraglia and L. Pontonnier, J. Phys.: Condens. Matter, 4 (1992) 5025) indicate that muons occupy interstitial sites without Co atoms in first-neighbour positions and diffuse through those sites, suggesting the existence of some degree of short-range order in the amorphous structure. Muon diffusion cannot be described by a single thermally activated process and is faster in the amorphous alloy than in the crystalline alloy. 相似文献
40.
C. M. Branco J. M. Ferreira M. O. W. Richardson P. Fael 《International Journal of Fatigue》1992,14(6):367-376
This paper presents results of a fatigue life investigations carried out in plate specimens of a fibre-glass-reinforced phenolic matrix composite. Tensile and Young's modulus data were obtained at four different testing temperatures (room temperature, 100, 150 and 200 °C). The fatigue S−N data were obtained at room temperature only and for two stress ratio values (R=0 and 0.4). Fatigue and tensile behaviour was assesesed in the composite with the fibres aligned in the longitudinal loading direction. The results were obtained for two values of volume fraction (0.28 and 0.42) and three different glass surface treatments. A detailed comparison of fatigue results is given taking into account several fatigue parameters and also the testing variables. Results of observations of SEM fracture surfaces are also presented. 相似文献