全文获取类型
收费全文 | 7531篇 |
免费 | 199篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 96篇 |
综合类 | 1篇 |
化学工业 | 1228篇 |
金属工艺 | 121篇 |
机械仪表 | 215篇 |
建筑科学 | 277篇 |
矿业工程 | 20篇 |
能源动力 | 290篇 |
轻工业 | 637篇 |
水利工程 | 96篇 |
石油天然气 | 30篇 |
武器工业 | 2篇 |
无线电 | 578篇 |
一般工业技术 | 1243篇 |
冶金工业 | 1935篇 |
原子能技术 | 45篇 |
自动化技术 | 922篇 |
出版年
2022年 | 59篇 |
2021年 | 92篇 |
2020年 | 78篇 |
2019年 | 97篇 |
2018年 | 99篇 |
2017年 | 101篇 |
2016年 | 122篇 |
2015年 | 101篇 |
2014年 | 142篇 |
2013年 | 336篇 |
2012年 | 284篇 |
2011年 | 472篇 |
2010年 | 367篇 |
2009年 | 285篇 |
2008年 | 389篇 |
2007年 | 382篇 |
2006年 | 322篇 |
2005年 | 303篇 |
2004年 | 244篇 |
2003年 | 246篇 |
2002年 | 256篇 |
2001年 | 142篇 |
2000年 | 131篇 |
1999年 | 140篇 |
1998年 | 342篇 |
1997年 | 236篇 |
1996年 | 194篇 |
1995年 | 159篇 |
1994年 | 140篇 |
1993年 | 135篇 |
1992年 | 95篇 |
1991年 | 60篇 |
1990年 | 79篇 |
1989年 | 72篇 |
1988年 | 67篇 |
1987年 | 57篇 |
1986年 | 89篇 |
1985年 | 68篇 |
1984年 | 60篇 |
1983年 | 56篇 |
1982年 | 49篇 |
1981年 | 46篇 |
1980年 | 46篇 |
1979年 | 37篇 |
1978年 | 44篇 |
1977年 | 66篇 |
1976年 | 69篇 |
1975年 | 40篇 |
1973年 | 32篇 |
1972年 | 34篇 |
排序方式: 共有7736条查询结果,搜索用时 0 毫秒
91.
Scott D. Stoller 《Distributed Computing》2000,13(2):85-98
Summary. This paper proposes a framework for detecting global state predicates in systems of processes with approximately-synchronized
real-time clocks. Timestamps from these clocks are used to define two orderings on events: “definitely occurred before” and
“possibly occurred before”. These orderings lead naturally to definitions of 3 distinct detection modalities, i.e., 3 meanings of “predicate held during a computation”, namely: (“ possibly held”), (“ definitely held”), and (“ definitely held in a specific global state”). This paper defines these modalities and gives efficient algorithms for detecting
them. The algorithms are based on algorithms of Garg and Waldecker, Alagar and Venkatesan, Cooper and Marzullo, and Fromentin
and Raynal. Complexity analysis shows that under reasonable assumptions, these real-time-clock-based detection algorithms
are less expensive than detection algorithms based on Lamport's happened-before ordering. Sample applications are given to
illustrate the benefits of this approach.
Received: January 1999 / Accepted: November 1999 相似文献
92.
Design and implementation of a vehicle interface protocol using an IEEE 1394 network 总被引:1,自引:0,他引:1
A wide variety of in-vehicle devices such as camera sensors, navigation systems, telematics and communication equipments have been incorporated into a vehicle to realize Intelligent Transport Systems (ITS) applications. Because an efficient standardized network is required, ITS Data Bus (IDB) has been discussed to carry high-speed multimedia data for audio, video and other real-time ITS applications. For connecting devices in a standardized manner, the IDB network has architecture with a gateway called vehicle interface which is located between automaker’s proprietary network and the standardized IDB network. IEEE 1394 (also known as iLink or FireWire), which can transport multimedia data for consumer electronics, is a good candidate for IDB network. In this paper, we analyze the issues for existing AV/C protocol (application layer protocol over IEEE 1394) to comprise the IDB network. In addition, we designed and implemented the vehicle interface protocol as a higher layer of IEEE 1394 to address the AV/C protocol issues for realizing the whole IDB network architecture. 相似文献
93.
Model selection for convolutive ICA with an application to spatiotemporal analysis of EEG 总被引:2,自引:0,他引:2
We present a new algorithm for maximum likelihood convolutive independent component analysis (ICA) in which components are unmixed using stable autoregressive filters determined implicitly by estimating a convolutive model of the mixing process. By introducing a convolutive mixing model for the components, we show how the order of the filters in the model can be correctly detected using Bayesian model selection. We demonstrate a framework for deconvolving a subspace of independent components in electroencephalography (EEG). Initial results suggest that in some cases, convolutive mixing may be a more realistic model for EEG signals than the instantaneous ICA model. 相似文献
94.
Weber GH Dillard SE Carr H Pascucci V Hamann B 《IEEE transactions on visualization and computer graphics》2007,13(2):330-341
Topology provides a foundation for the development of mathematically sound tools for processing and exploration of scalar fields. Existing topology-based methods can be used to identify interesting features in volumetric data sets, to find seed sets for accelerated isosurface extraction, or to treat individual connected components as distinct entities for isosurfacing or interval volume rendering. We describe a framework for direct volume rendering based on segmenting a volume into regions of equivalent contour topology and applying separate transfer functions to each region. Each region corresponds to a branch of a hierarchical contour tree decomposition, and a separate transfer function can be defined for it. The novel contributions of our work are: 1) a volume rendering framework and interface where a unique transfer function can be assigned to each subvolume corresponding to a branch of the contour tree, 2) a runtime method for adjusting data values to reflect contour tree simplifications, 3) an efficient way of mapping a spatial location into the contour tree to determine the applicable transfer function, and 4) an algorithm for hardware-accelerated direct volume rendering that visualizes the contour tree-based segmentation at interactive frame rates using graphics processing units (GPUs) that support loops and conditional branches in fragment programs 相似文献
95.
The effectiveness of intermittent, microclimate cooling for men who worked in US Army chemical protective clothing (modified mission-oriented protective posture level 3; MOPP 3) was examined. The hypothesis was that intermittent cooling on a 2 min on-off schedule using a liquid cooling garment (LCG) covering 72% of the body surface area would reduce heat strain comparably to constant cooling. Four male subjects completed three experiments at 30 degrees C, 30% relative humidity wearing the LCG under the MOPP 3 during 80 min of treadmill walking at 224 +/- 5 W . m(-2). Water temperature to the LCG was held constant at 21 degrees C. The experiments were; 1) constant cooling (CC); 2) intermittent cooling at 2-min intervals (IC); 3) no cooling (NC). Core temperature increased (1.6 +/- 0.2 degrees C) in NC, which was greater than IC (0.5 +/- 0.2 degrees C) and CC (0.5 +/- 0.3 degrees C) ( p < 0.05). Mean skin temperature was higher during NC (36.1 +/- 0.4 degrees C) than IC (33.7 +/- 0.6 degrees C) and CC (32.6 +/- 0.6 degrees C) and mean skin temperature was higher during IC than CC ( p < 0.05). Mean heart rate during NC (139 +/- 9 b . min(-1)) was greater than IC (110 +/- 10 b . min(-1)) and CC (107 +/- 9 b . min(-1)) ( p < 0.05). Cooling by conduction (K) during NC (94 +/- 4 W . m(-2)) was lower than IC (142 +/- 7 W . m(-2)) and CC (146 +/- 4 W . m(-2)) ( p < 0.05). These findings suggest that IC provided a favourable skin to LCG gradient for heat dissipation by conduction and reduced heat strain comparable to CC during exercise-heat stress in chemical protective clothing. 相似文献
96.
The Web has transformed the way organizations interact with clients, customers, and constituents. A large portion of these
groups is often neglected, namely people with disabilities. This study compares federal government, non-profit organization
(NPO), and corporate homepages accessibility to determine how accessible these websites are to people with disabilities and
how they compare to each other. The results indicate that federal homepages (23%), which are mandated to be accessible, are
significantly more accessible than NPO (11%) and corporate homepages (6%).
相似文献
Eleanor T. Loiacono (Corresponding author)Email: |
Scott McCoyEmail: |
97.
Comments on J. J. Christensen-Szalanski and L. R. Beach's (see record 1984-21471-001) conclusion that the attention given to commentaries and replies to articles did not justify the extra space. The author indicates that a 40% increase in space was associated with a 91% increase in citations; data do not argue against the use of commentaries. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
98.
C. V. Owen D. Cheong O. Buck T. E. Scott 《Metallurgical and Materials Transactions A》1984,15(1):147-153
Mechanical properties of V-Nb alloys were investigated from 78 to about 300 K. The effects of alloying composition on the
yield and flow stress are consistent with a hardening model due to the “misfit”" of one element in the matrix of the other.
Additions of up to about 0.6 at. pct of hydrogen have a moderate strengthening effect on the yield stress of high vanadium
alloys, but relatively little effect on the high niobium alloys. Little or no effect of adding hydrogen to any of the alloys
was observed for the strain hardening coefficient. High Nb alloys were found to be much less embrittled by small additions
of hydrogen than were high V alloys. In addition, the failure of severely embrittled alloys was found to be initiated intergranularly
by impingement of mechanical twins on grain boundaries. It is speculated that the grain boundaries may be enriched hydrogen. 相似文献
99.
100.
We provide a method for improving the parameterization of patching schemes that approximate Catmull‐Clark subdivision surfaces, such that the new parameterization conforms better to that of the original subdivision surface. We create this reparameterization in real‐time using a method that only depends on the topology of the surface and is independent of the surface's geometry. Our method can handle patches with more than one extraordinary vertex and avoids the combinatorial increase in both complexity and storage associated with multiple extraordinary vertices. Moreover, the reparameterization function is easy to implement and fast. 相似文献