全文获取类型
收费全文 | 885篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 6篇 |
综合类 | 1篇 |
化学工业 | 175篇 |
金属工艺 | 30篇 |
机械仪表 | 12篇 |
建筑科学 | 30篇 |
矿业工程 | 2篇 |
能源动力 | 11篇 |
轻工业 | 101篇 |
水利工程 | 2篇 |
武器工业 | 1篇 |
无线电 | 89篇 |
一般工业技术 | 129篇 |
冶金工业 | 177篇 |
原子能技术 | 11篇 |
自动化技术 | 142篇 |
出版年
2022年 | 8篇 |
2021年 | 11篇 |
2020年 | 14篇 |
2019年 | 13篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 21篇 |
2015年 | 20篇 |
2014年 | 23篇 |
2013年 | 34篇 |
2012年 | 26篇 |
2011年 | 39篇 |
2010年 | 30篇 |
2009年 | 22篇 |
2008年 | 40篇 |
2007年 | 31篇 |
2006年 | 27篇 |
2005年 | 23篇 |
2004年 | 28篇 |
2003年 | 21篇 |
2002年 | 18篇 |
2001年 | 15篇 |
2000年 | 22篇 |
1999年 | 13篇 |
1998年 | 57篇 |
1997年 | 31篇 |
1996年 | 30篇 |
1995年 | 33篇 |
1994年 | 16篇 |
1993年 | 19篇 |
1992年 | 12篇 |
1991年 | 17篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 20篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1969年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有919条查询结果,搜索用时 156 毫秒
21.
The technological properties of ABS polymers largely depend on the structure of the elastomer phase as well as on the elastomer/thermoplast interface. The morphological structure of such polymers can be determined from electron micrographs of ultramicrotome sections – after selective contrasting of the polybutadiene phase – or of replicas of fracture surfaces after selective chemical degradation. The various ABS polymers are classified by their manufacturing processes and their morphologies and characterized by electron micrographs. The degree and place of grafting are of particular importance. The quantitative determination of the surface- and internal grafting is achieved by combining the determination of the degree of grafting (extraction), the evaluation of the results obtained on particle counting, and a morphometric process. It is demonstrated that the morphometric process can in general be applied for the quantitative determination of the contrastable component in two-phase polymers. 相似文献
22.
A. Ritacco R. Adam A. Adane P. Ade P. André A. Beelen B. Belier A. Benoît A. Bideaud N. Billot O. Bourrion M. Calvo A. Catalano G. Coiffard B. Comis A. D’Addabbo F.-X. Désert S. Doyle J. Goupy C. Kramer S. Leclercq J. F. Macías-Pérez J. Martino P. Mauskopf A. Maury F. Mayet A. Monfardini F. Pajot E. Pascale L. Perotto G. Pisano N. Ponthieu M. Rebolo-Iglesias V. Revéret L. Rodriguez G. Savini K. Schuster A. Sievers C. Thum S. Triqueneaux C. Tucker R. Zylka 《Journal of Low Temperature Physics》2016,184(3-4):724-732
23.
Chuanjun Liu Marcus C. Lopes Sascha A. Pihan Daniela Fell Mordechai Sokuler Hans-Jürgen Butt Günter K. Auernhammer Elmar BonaccursoAuthor vitae 《Sensors and actuators. B, Chemical》2011,160(1):32
We present a method to measure the absorption of water molecules from the liquid and the vapour phase into polymer nano-films and the diffusion inside these films. Film thickness can be down to 45 nm. To demonstrate the possibilities of this method we use polymer films that are deposited on the upper side of a silicon cantilever by plasma polymerization of norbornene. When a microdrop of water is deposited onto the initially straight cantilever, the drop causes the cantilever to bend while it evaporates. Evaporation of such small water drops usually takes less than a second. An upwards bending is due to capillary forces and a downwards bending is due to the diffusion of water into the polymer film – and the consequent volume expansion (swelling) of the film. The magnitude of the capillary forces and the extent of swelling continuously change during drop evaporation. When drop evaporation is over the cantilever returns to its initial straight position. We simulate the time dependent bending with a numerical model that qualitatively agrees with the experiment. From the time dependence of cantilever bending we are able to determine the diffusion coefficient of water in the thin polymer film. 相似文献
24.
The quality of shadow mapping is traditionally limited by texture resolution. We present a novel lossless compression scheme for high‐resolution shadow maps based on precomputed multiresolution hierarchies. Traditional multiresolution trees can compactly represent homogeneous regions of shadow maps at coarser levels, but require many nodes for fine details. By conservatively adapting the depth map, we can significantly reduce the tree complexity. Our proposed method offers high compression rates, avoids quantization errors, exploits coherency along all data dimensions, and is well‐suited for GPU architectures. Our approach can be applied for coherent shadow maps as well, enabling several applications, including high‐quality soft shadows and dynamic lights moving on fixed‐trajectories. 相似文献
25.
Stroila M Eisemann E Hart J 《IEEE transactions on visualization and computer graphics》2008,14(1):135-145
Clip art is a simplified illustration form consisting of layered filled polygons or closed curves used to convey 3D shape information in a 2D vector graphics format. This paper focuses on the problem of direct conversion of smooth surfaces, ranging from the free-form shapes of art and design to the mathematical structures of geometry and topology, into a clip art form suitable for illustration use in books, papers and presentations.We show how to represent silhouette, shadow, gleam and other surface feature curves as the intersection of implicit surfaces, and derive equations for their efficient interrogation via particle chains. We further describe how to sort, orient, identify and fill the closed regions that overlay to form clip art. We demonstrate the results with numerous renderings used to illustrate the paper itself. 相似文献
26.
27.
28.
Serge A. Shapiro Susanne Rentsch Elmar Rothert 《Canadian Metallurgical Quarterly》2005,131(9):947-952
Operations including borehole fluid injections are typical for exploration and development of hydrocarbon or geothermic reservoirs. Microseismicity occurring during such operations has a large potential for understanding physics of the seismogenic process as well as in obtaining detailed information about reservoirs at locations as far as several kilometers from boreholes. We propose that the phenomenon of microseismicity triggering by borehole fluid injections is related to the process of the Frenkel–Biot slow wave propagation. In the low-frequency range (hours or days of fluid injection durations) this process reduces to the pore-pressure diffusion. We search for diffusion-related features of induced microseismicity. Two types of such signatures are considered. The first one is related to the geometry of microseismic clouds. Another type of signature is related to the probability of microearthquakes. On this basis we introduce a concept for interpretation of microseismic data which provides a possibility to infer information about hydraulic properties of rocks. Such information can be of significant importance for industrial applications and for understanding physical properties of geological structures. 相似文献
29.
R. Valle M.-H. Vidal-Sétif D. Schuster P. Le Vacon 《Metallurgical and Materials Transactions A》2004,35(10):3307-3317
The mechanical behavior (tension, fatigue, and notch sensitivity) of Al-based metal matrix composite (MMC) cross-ply laminates
is investigated. The two selected laminates, K139/A357 and N610/AU2, are reinforced by continuous K139 (carbon) or N610 (alumina)
fibers. These multiplies consist in the stacking of (quasi-unidirectional) quasi-UD preforms oriented at 0, ±45, and 90 deg,
the thermomechanical behavior of the corresponding quasi-UD composites being reported independently (Part I). The investigated
cross-ply laminates exhibit attractive static and cyclic performances and a low notch (circular hole) sensitivity. High-resolution
microfractography has led to a better understanding of the fracture mechanisms of these materials. In this respect, the role
of the transverse bundles is dominant in the tensile and fatigue failure of both laminates. However, the failure surfaces
are completely different: long fiber pullout in the K139/A357 laminate and much more planar areas in the N610/AU2 laminate.
Due to the rather low notch sensitivity, a large portion of the specimen section was already highly damaged during a non-negligible
part of the fatigue life: debonded interfaces in the K139/A357 laminate and multicracked and “crumbled” matrix in the N610/AU2
laminate. These mechanisms are in good agreement with the weak interface in the first case and the very low yield stress of
the AU2 matrix, much lower than the fatigue limit of the N610/AU2 laminate, in the second case. Moreover, compared to the
quasi-UD composites, the stress concentration around the notch allows further exacerbation of the fatigue mechanisms, much
more intense than that attained in “model” composites. 相似文献
30.
An enhanced timetabling procedure for the no-wait job shop problem: a complete local search approach
In this paper we consider the no-wait job shop problem with a makespan objective. This problem has usually been addressed by its decomposition into a sequencing and a timetabling problem. Here, first we focus on the timetabling problem and take advantage of the symmetry of the problem in order to suggest a new timetabling procedure. Secondly, we suggest embedding this timetabling into a recent metaheuristic named complete local search with memory. 相似文献