全文获取类型
收费全文 | 13437篇 |
免费 | 2012篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 600篇 |
综合类 | 653篇 |
化学工业 | 7798篇 |
金属工艺 | 189篇 |
机械仪表 | 127篇 |
建筑科学 | 477篇 |
矿业工程 | 49篇 |
能源动力 | 156篇 |
轻工业 | 655篇 |
水利工程 | 49篇 |
石油天然气 | 12篇 |
武器工业 | 1篇 |
无线电 | 329篇 |
一般工业技术 | 2359篇 |
冶金工业 | 519篇 |
原子能技术 | 21篇 |
自动化技术 | 1459篇 |
出版年
2023年 | 590篇 |
2022年 | 399篇 |
2021年 | 729篇 |
2020年 | 668篇 |
2019年 | 537篇 |
2018年 | 574篇 |
2017年 | 425篇 |
2016年 | 592篇 |
2015年 | 677篇 |
2014年 | 771篇 |
2013年 | 1022篇 |
2012年 | 590篇 |
2011年 | 540篇 |
2010年 | 798篇 |
2009年 | 839篇 |
2008年 | 414篇 |
2007年 | 381篇 |
2006年 | 239篇 |
2005年 | 240篇 |
2004年 | 294篇 |
2003年 | 232篇 |
2002年 | 259篇 |
2001年 | 125篇 |
1999年 | 96篇 |
1998年 | 133篇 |
1997年 | 114篇 |
1996年 | 105篇 |
1995年 | 125篇 |
1994年 | 95篇 |
1993年 | 151篇 |
1992年 | 109篇 |
1991年 | 90篇 |
1990年 | 116篇 |
1989年 | 109篇 |
1988年 | 82篇 |
1987年 | 102篇 |
1986年 | 114篇 |
1985年 | 103篇 |
1984年 | 93篇 |
1983年 | 119篇 |
1982年 | 87篇 |
1981年 | 121篇 |
1980年 | 94篇 |
1979年 | 76篇 |
1977年 | 70篇 |
1976年 | 73篇 |
1975年 | 72篇 |
1974年 | 76篇 |
1973年 | 140篇 |
1972年 | 79篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
In Face on Facebook: Brooklyn's Drag Community and Sociotechnical Practices of Online Communication 下载免费PDF全文
Recently, Brooklyn has seen an explosion of drag culture, with dozens of performers taking the stage in any given week. Social media plays a vital role for members of this community, simultaneously allowing self‐promotion and community solidarity. Drawing on focus group interviews, we analyze the communication practices of Brooklyn's drag performers, examining both the advantages and drawbacks of social media platforms. Using conceptual frameworks of faceted identity and relational labor, our discussion focuses on affordances and constraints of multifaceted identity in online contexts and theories of seamful design. We contend that by analyzing online communication practices of drag performers, it becomes possible to identify gaps between embedded ideologies of mainstream social media technologies and the localized values of outsider communities. 相似文献
102.
103.
104.
Adam Klimanek 《Archives of Computational Methods in Engineering》2013,20(1):61-109
Numerical modelling of natural draft wet-cooling towers is considered in this paper. Development of a complete CFD model capable of predicting cooling tower performance under various operating conditions is presented. A step-by-step approach is employed, thus one-dimensional numerical modelling of counterflow heat and mass exchangers is extensively presented first. This is followed by reduced order modelling of heat and mass transfer in cooling tower fills by means of proper orthogonal decomposition radial basis function networks. Then the approaches in modelling of droplet zones (rain and spray zones) are discussed. Finally the two and three-dimensional CFD models are discussed. 相似文献
105.
Sealed nanofluidic channels with cross-sections as small as 60 nm × 60 nm were created in polymer bilayers using the focused X-rays of a scanning transmission X-ray microscope. These structures were then characterized by near-edge X-ray absorption fine structure spectromicroscopy, atomic force microscopy and scanning electron microscopy. The cross-sectional area of the nanochannels could be tuned by adjusting the area patterned in x and y and/or manipulating the bottom layer thickness. The maximum length was found to be limited by the efficiency of excavation of patterned material out of the channel, and the stability of the polymer overlayer which seals the channel. Schemes toward interfacing these nanochannels with conventional microfluidics are discussed. 相似文献
106.
On finite dynamic equations for fluid-saturated porous media 总被引:2,自引:0,他引:2
Summary The paper concerns the relations between two principally different approaches to the formulation of momentum balance equations in porous media theories, namely, the dynamic approach similar to Biot's theory and the modern approach as a result of mixture theories extended by the concept of volume fractions. In particular, it is shown that both approaches necessarily lead to the same type of momentum balance equations and furthermore contain, in a certain sense, within the geometrically linear case, the well-known classical equations of Biot's theory. 相似文献
107.
We present a method depending on matrix continued fractions and Sturm's comparison theorem to obtain verified inclusions for eigenvalues of the underlying boundary value problem of the first-order phase locked loop equation $pu'' + (\lambda + \tilde g)u = 0$ ,p = 1/SNR with general phase detector characteristic $\tilde g(\phi )$ . 相似文献
108.
Prof. Dr. rer. nat. G. Lehner 《Electrical Engineering (Archiv fur Elektrotechnik)》1995,78(4):209-217
Contents We discuss some initial and boundary value problems of one-dimensional electromagnetic field diffusion. The solutions can be given by infinite series in two essentially different (however equivalent) forms, one being the usual Fourier-expansion and the other one being an infinite series of Gaussian exponentials or related functions (as for instance error-functions). The second form can be obtained by using infinitely many images to fulfill initial and boundary conditions. Finally the mathematical relations between the two equivalent types of solutions are discussed in terms of -functions and their transformation properties. The existence of the solutions in these two different forms is very interesting from a numerical point of view also.
Die Diffusion elektromagnetischer Felder, -Funktionen und Spiegelungsmethoden
Übersicht Es werden einige Anfangs- und Randwertprobleme eindimensionaler elektromagnetischer Felddiffusion erörtert. Die Lösungen können in zwei wesentlich verschiedenen (jedoch gleichwertigen) Formen angegeben werden, erstens in Form üblicher Fourier-Reihen und zweitens in Form unendlicher Reihen von Gaußschen Exponentialfunktionen oder damit verwandter Funktionen (z.B. Fehlerfunktionen). Diese zweite Form der Lösungen läßt sich durch die Anwendung unendlich oft wiederholter Spiegelung zur Erfüllung der Rand- und Anfangsbedingung anschaulich interpretieren. Abschließend werden die beiden Lösungstypen mit Hilfe von -Funktionen und deren Transformationseigenschaften erläutert. Die Verfügbarkeit der Lösungen in beiden Formen ist auch numerisch sehr interessant.相似文献
109.
Adam Drozdek 《AI & Society》1995,9(4):389-395
The question whether or not computers can think was first asked in print by Alan Turing in his seminal 1950 article. In order to avoid defining what a computer is or what thinking is, Turing resorts to the imitation game which is a test that allows us to determine whether or not a machine can think. That is, if an interrogator is unable to tell whether responses to his questions come from a human being or from a machine, the machine is imitating a human being so well that it has to be acknowledged that these responses result from its thinking. However, then as now, it is not an indisputable claim that machines could think, and an unceasing stream of papers discussing the validity of the test proves this point. There are many arguments in favour of, as well as against, the claims borne by the test, and Turing himself discusses some of them. In his view, there are mice possible objections to the concept of a thinking machine, which he eventually dismisses as weak, irrelevant, or plain false. However, as he admits, he can present no very convincing arguments of a positive nature to support my views. If I had I should not have taken such pains to point out the fallacies in contrary views. 相似文献
110.
Almawgani A. H. M. Alhawari Adam R. H. Hindi Ayman Taher Al-Arashi Waled Hussein Al-Ashwal A. Y. 《Multidimensional Systems and Signal Processing》2022,33(2):561-578
Multidimensional Systems and Signal Processing - Digital images are commonly used in steganography due to the popularity of digital image transfer and exchange through the Internet. However, the... 相似文献