全文获取类型
收费全文 | 8799篇 |
免费 | 412篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 118篇 |
综合类 | 38篇 |
化学工业 | 2252篇 |
金属工艺 | 227篇 |
机械仪表 | 184篇 |
建筑科学 | 601篇 |
矿业工程 | 20篇 |
能源动力 | 281篇 |
轻工业 | 838篇 |
水利工程 | 87篇 |
石油天然气 | 43篇 |
武器工业 | 1篇 |
无线电 | 658篇 |
一般工业技术 | 1449篇 |
冶金工业 | 553篇 |
原子能技术 | 58篇 |
自动化技术 | 1815篇 |
出版年
2023年 | 85篇 |
2022年 | 202篇 |
2021年 | 334篇 |
2020年 | 184篇 |
2019年 | 200篇 |
2018年 | 270篇 |
2017年 | 233篇 |
2016年 | 314篇 |
2015年 | 233篇 |
2014年 | 338篇 |
2013年 | 625篇 |
2012年 | 482篇 |
2011年 | 614篇 |
2010年 | 426篇 |
2009年 | 491篇 |
2008年 | 453篇 |
2007年 | 410篇 |
2006年 | 341篇 |
2005年 | 291篇 |
2004年 | 269篇 |
2003年 | 258篇 |
2002年 | 189篇 |
2001年 | 137篇 |
2000年 | 137篇 |
1999年 | 114篇 |
1998年 | 128篇 |
1997年 | 130篇 |
1996年 | 96篇 |
1995年 | 80篇 |
1994年 | 80篇 |
1993年 | 84篇 |
1992年 | 58篇 |
1991年 | 60篇 |
1990年 | 61篇 |
1989年 | 68篇 |
1988年 | 49篇 |
1987年 | 47篇 |
1986年 | 50篇 |
1985年 | 53篇 |
1984年 | 62篇 |
1983年 | 44篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 39篇 |
1979年 | 32篇 |
1978年 | 34篇 |
1977年 | 33篇 |
1976年 | 39篇 |
1975年 | 40篇 |
1973年 | 36篇 |
排序方式: 共有9223条查询结果,搜索用时 0 毫秒
21.
Summary A derivation of a parallel algorithm for rank order filtering is presented. Both derivation and result differ from earlier designs: the derivations are less complicated and the result allows a number of different implementations. The same derivation is used to design a collection of priority queues. Both filters and priority queues are highly efficient: they have constant response time and small latency.
Anne Kaldewaij received an M.Sc. degree in Mathematics from the University of Utrecht (The Netherlands) and a Ph.D. degree in Computing Science from the Eindhoven University of Technology. Currently, he is associate professor in Computing Science at Eindhoven University. His research includes parallel programming and the design of algorithms and data structures. He enjoys teaching and he has written a number of textbooks on mathematics and programming.
Jan Tijmen Udding received an M.Sc. degree in Mathematics in 1980 and a Ph.D. degree in Computing Science in 1984 from Eindhoven University of Technology. Currently, he is associate professor at Groningen University. His main research interests are mathematical aspects of VLSI, program derivation and correctness, and functional programming. 相似文献
22.
Abderrafi M. Ougouag Jan Leen Kloosterman Wilfred F.G. van Rooijen Hans D. Gougar William K. Terry 《Nuclear Engineering and Design》2006,236(5-6):669-2004
Models and methods are presented for determining practical limits of the packing density of TRISO particles in fuel pebbles for a pebble-bed reactor (PBR). These models are devised for designing and interpreting fuel testing experiments. Two processes for particle failure are accounted for: failure of touching particles at the pressing stage in the pebble manufacturing process and failure due to inner pressure buildup during irradiation. The second process gains importance with increasing fuel temperature, which limits the particle packing density and the corresponding fuel enrichment. Suggestions for improvements to the models are presented. 相似文献
23.
We describe planar buried heterostructure lasers which have low capacitance (lpF), large bandwidth (19GHz), high power (>20mW/facet) and high temperature operation (100°C). These lasers are very suitable for long-distance, highspeed digital and analogue signal transmission. 相似文献
24.
25.
Jan A. Derecki 《Journal of Great Lakes research》1985,11(3):201-207
Periodic man-made changes in the outlet of Lake Huron through the St. Clair River date back to the middle of the last century. These artificial channel changes have been well documented during the present century. They consist of dredging for commercial gravel removal in the upper river during 1908–25 and uncompensated navigation improvements for the 7.6-m (25-ft) and 8.2-m (27-ft) projects completed in 1933 and 1962, respectively. The total effect of these changes on the levels of Lakes Michigan and Huron (hydraulically one lake) and on the upper St. Clair River profile was determined with dynamic flow models. The ultimate effect of the above dredging was a permanent lowering of the Lake Michigan-Huron levels 0.27 m (0.89 ft), which represents a tremendous loss of freshwater resource [32 km3 (7.7 mi3)]. 相似文献
26.
27.
This paper presents work directed at capturing the entrepreneurial and collaborative activity of university researchers. The Triple Helix points to the emergence of the entrepreneurial university as well as to an increasing overlay of activities in universities, industry and government. This study explores ways in which patent-based metrics could be utilized in a Triple Helix context, and how hybrid indicators could be developed by combining patent with survey data. More specifically, it aims to develop indicators that connect technological inventiveness of university researchers to both funding organizations and users, as well as to entrepreneurial activities by academics. The paper develops a simplified model of the innovation process to benchmark the relevance of the indicators to the Triple Helix. An analysis of Finnish academic patents illustrates that patent data can already provide useful indicators but, on its own, cannot provide information about how academic patents are interconnected with government or industry through funding or utilization links. An exclusive analysis of patents can point to patent concentrations on certain universities, to inventors and assignees, or to potential gaps in translating applied science into industrial technology. However, the patent data had to be combined with an inventor survey in order to relate academic patents more to their Triple Helix environment. The survey indicated that most patented academic inventions are connected to (often publicly funded) scientific research by the inventors and tend to be utilized in large firms rather than in start-up companies founded by academic entrepreneurs. 相似文献
28.
29.
The Steady radial distribution of chemical species in a wire‐to‐cylinder ozone generator filled with pure oxygen has been computed by applying four different plasma chemistry models of increasing complexity. The most complete model considers ten species (e, O2 +, O2 ?, O3 ?, O?, O2, O2(1Δg), O2(1∑g +), O and O3) and 79 reactions, including ionization by electron impact, electron attachment and detachment, electron-ion recombination, charge transfer, etc. The chemical model is coupled with the electrical model through Poisson's equation. The spatially averaged ozone density has been computed as a function of the current intensity and compared with the experimental values obtained by UV spectroscopy. 相似文献
30.
van Gelderen Amos; Schoonen Rob; de Glopper Kees; Hulstijn Jan; Simis Annegien; Snellings Patrick; Stevenson Marie 《Canadian Metallurgical Quarterly》2004,96(1):19
The authors report results of a study into the role of components of first-language (L1; Dutch) and second-language (L2; English) reading comprehension. Differences in the contributions of components of L1 and L2 reading comprehension are analyzed, in particular processing speed in L1 and L2. Findings indicate that regression weights of the L1 and L2 components are different. Although correlations between most processing speed components and reading comprehension are substantial, there are no unique contributions to the explanation of either L1 or L2 reading comprehension when linguistic and metacognitive knowledge are accounted for. In addition, L1 reading comprehension is shown to have a large contribution to L2 reading comprehension, supporting theories of L1-L2 transfer of reading skills. Results are discussed from a developmental perspective. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献