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91.
A range query finds the aggregated values over all selected cells of an online analytical processing (OLAP) data cube where
the selection is specified by the ranges of contiguous values for each dimension. An important issue in reality is how to
preserve the confidential information in individual data cells while still providing an accurate estimation of the original
aggregated values for range queries. In this paper, we propose an effective solution, called the zero-sum method, to this
problem. We derive theoretical formulas to analyse the performance of our method. Empirical experiments are also carried out
by using analytical processing benchmark (APB) dataset from the OLAP Council. Various parameters, such as the privacy factor
and the accuracy factor, have been considered and tested in the experiments. Finally, our experimental results show that there
is a trade-off between privacy preservation and range query accuracy, and the zero-sum method has fulfilled three design goals:
security, accuracy, and accessibility.
Sam Y. Sung is an Associate Professor in the Department of Computer Science, School of Computing, National University of Singapore. He
received a B.Sc. from the National Taiwan University in 1973, the M.Sc. and Ph.D. in computer science from the University
of Minnesota in 1977 and 1983, respectively. He was with the University of Oklahoma and University of Memphis in the United
States before joining the National University of Singapore. His research interests include information retrieval, data mining,
pictorial databases and mobile computing. He has published more than 80 papers in various conferences and journals, including
IEEE Transaction on Software Engineering, IEEE Transaction on Knowledge & Data Engineering, etc.
Yao Liu received the B.E. degree in computer science and technology from Peking University in 1996 and the MS. degree from the Software
Institute of the Chinese Science Academy in 1999. Currently, she is a Ph.D. candidate in the Department of Computer Science
at the National University of Singapore. Her research interests include data warehousing, database security, data mining and
high-speed networking.
Hui Xiong received the B.E. degree in Automation from the University of Science and Technology of China, Hefei, China, in 1995, the
M.S. degree in Computer Science from the National University of Singapore, Singapore, in 2000, and the Ph.D. degree in Computer
Science from the University of Minnesota, Minneapolis, MN, USA, in 2005. He is currently an Assistant Professor of Computer
Information Systems in the Management Science & Information Systems Department at Rutgers University, NJ, USA. His research
interests include data mining, databases, and statistical computing with applications in bioinformatics, database security,
and self-managing systems. He is a member of the IEEE Computer Society and the ACM.
Peter A. Ng is currently the Chairperson and Professor of Computer Science at the University of Texas—Pan American. He received his Ph.D.
from the University of Texas–Austin in 1974. Previously, he had served as the Vice President at the Fudan International Institute
for Information Science and Technology, Shanghai, China, from 1999 to 2002, and the Executive Director for the Global e-Learning
Project at the University of Nebraska at Omaha, 2000–2003. He was appointed as an Advisory Professor of Computer Science at
Fudan University, Shanghai, China in 1999. His recent research focuses on document and information-based processing, retrieval
and management. He has published many journal and conference articles in this area. He had served as the Editor-in-Chief for
the Journal on Systems Integration (1991–2001) and as Advisory Editor for the Data and Knowledge Engineering Journal since
1989. 相似文献
92.
Naglieri Jack A.; De Lauder Brianna Y.; Goldstein Sam; Schwebech Adam 《Canadian Metallurgical Quarterly》2006,21(1):62
The relationships between Wechsler Intelligence Scale for Children-Third Edition (WISC-III) and the Cognitive Assessment System (CAS) with the Woodcock-Johnson Tests of Achievement (WJ-III) were examined for a sample of 119 children (87 males and 32 females) ages 6 to 16. The sample was comprised of children who were referred to a specialty clinic for evaluation. Participants were administered the WISC-III, the CAS, and the WJ-III, in that order. Results indicated that CAS/WJ-III correlations were consistently significantly higher than those found for the WISC-III/WJ-III. The four separate CAS scales added more variance above and beyond the four separate WISC-III scales than the WISC-III added above and beyond the CAS. In addition, the CAS Full Scale accounted for more unique variance and was a stronger predictor of WJ-III Academic Skills Cluster than the WISC-III Full Scale IQ. These results support the validity of the Planning, Attention, Simultaneous, and Successive theory as measured by the CAS in relation to the general intelligence model measured using the WISC-III for explaining variance in achievement for this clinical sample. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
93.
Joseph Sam Armijo Piyush Kar Manoranjan Misra 《Nuclear Engineering and Design》2006,236(24):2589-2598
The reference waste package design and operating mode to be used in the Yucca Mountain Repository is reviewed. An alternate (second generation) operating concept and waste package design is proposed to reduce the risk of localized corrosion of waste packages and to reduce repository costs. The second generation waste package design and storage concept is proposed for implementation after the initial licensing and operation of the reference repository design. Implementation of the second generation concept at Yucca Mountain would follow regulatory processes analogous to those used successfully to extend the design life and uprate the power of commercial light water nuclear reactors in the United States. The second generation concept utilizes the benefits of hot dry storage to minimize the potential for localized corrosion of the waste package by liquid electrolytes. The second generation concept permits major reductions in repository costs by increasing the number of fuel assemblies stored in each waste package, by eliminating the need for titanium drip shields and by fabricating the outer container from corrosion resistant low alloy carbon steel. 相似文献
94.
Xiaobo Chao Yafei Jia Charles M. Cooper F. Douglas Shields Jr. Sam S. Y. Wang 《Canadian Metallurgical Quarterly》2006,132(11):1498-1507
A three-dimensional numerical model was developed for simulating the phosphorus concentration in shallow lakes. In this model, the computational domain was divided into two parts: the water column and the bed sediment layer. The processes of mineralization, settling, adsorption, desorption, bed release (diffusion), growth, and death of phytoplankton were taken into account, and the concentration of organic phosphorus, phosphate, and related water quality constituents was simulated. The concentrations of adsorbed (particulate) and dissolved phosphate due to adsorption-desorption were calculated using two formulas derived based on the Langmuir equation. The release rate of phosphorus from the bed sediment layer was calculated by considering the effects of the concentration gradient across the water-sediment interface, pH, temperature, dissolved oxygen concentration, and flow conditions. The adsorption and desorption of phosphate from sediment particles, as well as its release from bed sediment, were verified using laboratory experimental data. The model was calibrated and applied to Deep Hollow Lake in the Mississippi alluvial plain. The simulated trends and magnitudes of phosphorus concentration were compared with field observations. The simulation results show that there are strong interactions between sediment-related processes and phosphorus concentration. 相似文献
95.
Several existing formulas for the initial porosity and settling velocity of sediment have been tested by using extensive data collected from different countries and regions, and modified to achieve better reliability or convenience in use. 相似文献
96.
Giuseppe Fregapane Douglas B. Sarney Sydney G. Greenberg Dorothy J. Knight Evgeny N. Vulfson 《Journal of the American Oil Chemists' Society》1994,71(1):87-91
5-O-Acyl-1,2-O-isopropylidene-D-xylofuranose and 6-O-acyl1,2∶3,4-di-O-isopropylidene-D-galactopyranose were enzymatically prepared from the corresponding monosaccharide acetals and commercial
(crude) fatty acid mixtures. Subsequent acid-catalyzed hydrolysis of the isopropylidene group(s) gave monosaccharide esters
with overall yields of 59–88%, where the monoester content was at least 80% (galactose oleate) and typically 90% for the other
preparations. In contrast to sugar fatty acid esters prepared by conventional, high-temperature (trans)esterification, the
enzymatically obtained monosaccharide esters contained no appreciable quantities of undersirable side products, and the only
contaminants were monosaccharides and fatty acids. 相似文献
97.
DL Sam 《Canadian Metallurgical Quarterly》1998,3(1-2):5-18
OBJECTIVE: To find out the degree of life satisfaction among adolescents with immigrant background, and the factors that may predict the level of life satisfaction among them. METHOD: Five hundred and six adolescents (mean age = 15.34, SD = 1.67) with immigrant background from Vietnam, Pakistan, Chile and Turkey were recruited from five major Norwegian cities, and were asked to fill in a questionnaire with several measures, including demographic information, life satisfaction, acculturation strategies, ethnic identity and mastery. A control group involving 209 Norwegian youth were also included in the study. RESULTS: On the whole the adolescents with immigrant background were found to be fairly satisfied with their life (M = 3.55, SD = 0.81). Using Socio-Economic Status as covariance, adolescents with immigrant background did not differ from their Norwegian counterparts on life satisfaction level (F = 0.58, p > 0.05). Chileans were found to be the most satisfied group, and Vietnamese the least satisfied. The higher life satisfaction among Chileans compared with the other ethnic groups is viewed as a possible selection bias. While demographic factors accounted for just 4% of the explained variance, personal factors accounted for over 20% of the explained variance. Mastery (beta = 0.39) and ethnic identity (beta = 0.17) were the two most important predictors of life satisfaction. Living in an ethnically homogenous neighbourhood was also found to be related to life satisfaction. Perceived discrimination and integration as an acculturation strategy were not related to life satisfaction. CONCLUSION: The study concludes that helping adolescents with immigrant background to develop a good sense of mastery and a positive ethnic identity will go a long way to boost their life satisfaction. 相似文献
98.
99.
Osteotomy is the well-established treatment of Blount's disease (tibia vara), although the types of fixation used vary considerably. The use of dynamic axial external fixation to stabilize osteotomies for tibia vara until solid union occurs without the use of supplemental casting has not been reported by other authors. From 1985 until the present, we have used osteotomy with dynamic axial external fixation as treatment of 31 tibiae in 23 patients. All osteotomies healed and there was no postoperative loss of correction. There was an average correction of 20 degrees between the pre- and postoperative mechanical axis. Advantages of dynamic axial external fixation include ease of application, adjustability, early weight bearing, the ability to lengthen the extremity, and no second operation for removal of hardware. Based on our results, we believe that dynamic axial external fixation is an excellent form of osteotomy stabilization in the surgical treatment of tibia vara. 相似文献
100.