全文获取类型
收费全文 | 910篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 16篇 |
综合类 | 1篇 |
化学工业 | 133篇 |
金属工艺 | 10篇 |
机械仪表 | 25篇 |
建筑科学 | 37篇 |
矿业工程 | 4篇 |
能源动力 | 26篇 |
轻工业 | 71篇 |
水利工程 | 27篇 |
石油天然气 | 3篇 |
无线电 | 106篇 |
一般工业技术 | 135篇 |
冶金工业 | 179篇 |
原子能技术 | 4篇 |
自动化技术 | 149篇 |
出版年
2022年 | 3篇 |
2021年 | 11篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 8篇 |
2016年 | 20篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 33篇 |
2012年 | 44篇 |
2011年 | 50篇 |
2010年 | 45篇 |
2009年 | 54篇 |
2008年 | 60篇 |
2007年 | 42篇 |
2006年 | 42篇 |
2005年 | 38篇 |
2004年 | 22篇 |
2003年 | 30篇 |
2002年 | 22篇 |
2001年 | 15篇 |
2000年 | 28篇 |
1999年 | 21篇 |
1998年 | 45篇 |
1997年 | 34篇 |
1996年 | 17篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 10篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1977年 | 10篇 |
1976年 | 16篇 |
1975年 | 3篇 |
1974年 | 7篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有926条查询结果,搜索用时 15 毫秒
131.
132.
Zr
100-xA1x (x ≤ 40) metastable alloys were synthesized by high- energy ball milling of elemental Zr and Al powders: supersaturated
substitutional cph solid solution for x ≤ 15 and an amorphous phase for x ≥ 17.5. We performed a calorimetric study of the
thermodynamics and kinetics of the metastable- to- equilibrium transformations of these phases. Their stability range (temperature/composition),
as well as the apparent activation energies associated with the transformations, were determined. The transformation enthalpies
were measured and used to determine the enthalpy of formation for these metastable phases. For both as- milled and relaxed
amorphous phases, the measured enthalpy of crystallization is compared with those estimated for an undercooled liquid. Different
amounts of retained entropy at the glass transition temperature were used to estimate the enthalpy loss upon undercooling
due to the excess specific heat.
This paper was presented at the Thermodynamics and Phase Equilibria of Metastable Phases Symposium at the Spring TMS Meeting,
March 1-4,1992, in San Diego. The symposium was organized by Philip Nash, Illinois Institute of Technology, and Ricardo Schwarz,
Los Alamos National Laboratory. 相似文献
133.
Dr. H. Brunner 《Computing》1979,23(2):179-187
It has been shown that if a Volterra integral equation of the first kind with continuous kernel is solved numerically in a given intervalI by collocation in the space of piecewise polynomials of degreem≧0 and possessing finite discontinuities at their knotsZ N then a careful choice of the collocation points yields convergence of orderp=m+2 on a certain finite subset ofI (while the global convergence order ism+1; this subset does not contain the knotsZ N . In this note it will be shown that superconvergence onZ N can be attained only if some of the collocation points coalesce (Hermite-type collocation). 相似文献
134.
135.
HG Brunner T Hulsebos PM Steijlen DJ der Kinderen A vd Steen BC Hamel 《Canadian Metallurgical Quarterly》1993,46(4):472-474
We have performed linkage analysis in a small family with autosomal dominant inheritance of multiple café-au-lait spots (CLS) in order to clarify its relationship to classical von Recklinghausen disease (NF 1). We found that an affected woman had transmitted a different haplotype for markers flanking the NF1 gene to both of her affected daughters. These results exclude an allelic mutation of the NF 1 gene on chromosome 17 as the cause for inherited café-au-lait spots in this family. 相似文献
136.
137.
138.
This paper surveys machine induction techniques for database management and analysis. Our premise is that machine induction facilitates an evolution from relatively unstructured data stores to efficient and correct database implementations. 相似文献
139.
A theory of weak stability for linear multistep methods for the numerical solution of Volterra integro-differential equations is developed, and a connection between this theory and the corresponding theory for ordinary differential equations is established. In addition, the order of such methods is discussed, and a new starting procedure is proposed and analyzed. 相似文献
140.
Peter O Ajemba Lino Ramirez Nelson G Durdle Doug L Hill V James Raso 《IEEE transactions on information technology in biomedicine》2005,9(2):276-282
A support vector classifier (SVC) approach was employed in predicting the risk of progression of adolescent idiopathic scoliosis (AIS), a condition that causes visible trunk asymmetries. As the aetiology of AIS is unknown, its risk of progression can only be predicted from measured indicators. Previous studies suggest that individual indicators of AIS do not reliably predict its risk of progression. Complex indicators with better predictive values have been developed but are unsuitable for clinical use as obtaining their values is often onerous, involving much skill and repeated measurements taken over time. Based on the hypothesis that combining common indicators of AIS using an SVC approach would produce better prediction results more quickly, we conducted a study using three datasets comprising a total of 44 moderate AIS patients (30 observed, 14 treated with brace). Of the 44 patients, 13 progressed less than 5 degrees and 31 progressed more than 5 degrees. One dataset comprised all the patients. A second dataset comprised all the observed patients and a third comprised all the brace-treated patients. Twenty-one radiographic and clinical indicators were obtained for each patient. The result of testing on the three datasets showed that the system achieved 100% accuracy in training and 65%-80% accuracy in testing. It outperformed a "statistically equivalent" logistic regression model and a stepwise linear regression model on the said datasets. It took less than 20 min per patient to measure the indicators, input their values into the system, and produce the needed results, making the system viable for use in a clinical environment. 相似文献