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1.
The trends in high density interconnection (HDI) multichip module (MCM) techniques that have the potential to reduce interconnection cost and production time are described. The implementation in laminated dielectric (MCM-L) technology of a workstation processor core illustrates current substrate technology capabilities. The design, routing, layout and thermal management of the processor core are described. Thin-film deposited dielectric (MCM-D) technology is discussed as a cost-effective method for future interconnection applications 相似文献
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VRML stands for Virtual Reality Modeling Language. Technically, VRML is neither virtual reality nor a modeling language. Virtual reality generally implies an immersive 3D experience, which typically requires a head mounted display (HMD) and 3D input devices, such as digital gloves. VRML neither requires nor imposes immersion. Furthermore, a true modeling language would contain richer geometric modeling primitives and mechanisms. VRML provides a bare minimum of geometric modeling features but contains numerous features unavailable in a modeling language. If VRML is not virtual reality or a modeling language, what is it? This question has several answers. At its core, VRML serves as a 3D interchange format. It defines most of the commonly used semantics found in today's 3D applications such as hierarchical transformations, light sources, viewpoints, geometry, animation, fog, material properties, and texture mapping. Here's a second answer to: what is VRML? It's a 3D analog to HTML. This means that VRML serves as a simple, multiplatform language for publishing 3D Web pages. The fact that some information, including games, engineering models, scientific visualizations, educational experiences, and architecture, can best be experienced in 3D has motivated this language. Typically, these types of projects require intensive interaction, animation, and user participation and exploration beyond what a page, text, or image based format can handle. Another answer is that VRML provides the technology to integrate 3D, 2D, text, and multimedia into a coherent model 相似文献
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Laura M. Haas Michael J. Carey Miron Livny Amit Shukla 《The VLDB Journal The International Journal on Very Large Data Bases》1997,6(3):241-256
In this paper, we re-examine the results of prior work on methods for computing ad hoc joins. We develop a detailed cost model for predicting join algorithm performance, and we use the model to develop cost formulas
for the major ad hoc join methods found in the relational database literature. We show that various pieces of “common wisdom” about join algorithm
performance fail to hold up when analyzed carefully, and we use our detailed cost model to derive op
timal buffer allocation schemes for each of the join methods examined here. We show that optimizing their buffer allocations
can lead to large performance improvements, e.g., as much as a 400% improvement in some cases. We also validate our cost model's
predictions by measuring an actual implementation of each join algorithm considered. The results of this work should be directly
useful to implementors of relational query optimizers and query processing systems.
Edited by M. Adiba. Received May 1993 / Accepted April 1996 相似文献
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Lonigan Christopher J.; Carey Michael P.; Finch A. J. 《Canadian Metallurgical Quarterly》1994,62(5):1000
Self-reported depression and anxiety were examined in 233 inpatient children (aged 6–17 yrs) diagnosed with either an anxiety disorder or a depressive disorder. Depressed children reported more problems related to a loss of interest and low motivation, and they had a more negative view of themselves. Anxious children reported more worry about the future, their well-being, and the reactions of others. The groups did not differ in the degree of depressed affect reported in terms of being sad, lethargic, bothered by things, or feeling alone and isolated. Findings suggest that a general negative affectivity component is common to both anxiety and depression disorders and measures. Results demonstrate that anxiety and depression in children have distinguishing features that can be measured by common self-report instruments, and the findings indicate that one factor that may distinguish between anxiety and depression in children is positive affectivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
A.N. Al-Omari G.P. Carey S. Hallstein J.P. Watson G. Dang K.L. Lear 《Photonics Technology Letters, IEEE》2006,18(11):1225-1227
Increasing copper plated heatsink radii from 0 to 4 /spl mu/m greater than the mesa in vertical-cavity surface-emitting lasers (VCSELs) reduced the measured thermal resistance for a range of device sizes to values 50% lower than previously reported over a range of device sizes. For a 9-/spl mu/m diameter oxide aperture, the larger heatsink increases output power and bandwidth by 131% and 40%, respectively. The lasers exhibit a 3-dB modulation frequency bandwidth up to 9.8 GHz at 10.5 kA/cm/sup 2/. The functional dependence of thermal resistance on oxide aperture diameter indicates the importance of lateral heat flow to mesa sidewalls. 相似文献
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J. D. Carey R. C. Smith S. R. P. Silva 《Journal of Materials Science: Materials in Electronics》2006,17(6):405-412
The influence of the different types of bonding present in a range of carbon based materials is discussed as a precursor to
describing the field emission characteristics of carbon cold cathode materials. Some of the controlling factors which govern
electron emission from carbon based cathodes are discussed. It is shown that from disordered carbon films the interplay between
the clustered sp2 phase and the insulating sp3 matrix is important. The transition from a ‘back contact’ to ‘front surface’ controlled emission mechanism is described in
terms of the sp2 content and field penetration. A possible reason for high field enhancement factors found in disordered films also is provided.
It is further shown that changes to the sp2 phase by current stressing can improve the field emission characteristics. Emission from carbon nanotubes is also discussed
and the prospects for new types of nanotube – polymer composite based cathodes are also considered. 相似文献