全文获取类型
收费全文 | 158篇 |
免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 40篇 |
金属工艺 | 11篇 |
机械仪表 | 1篇 |
建筑科学 | 4篇 |
能源动力 | 5篇 |
轻工业 | 10篇 |
水利工程 | 2篇 |
无线电 | 12篇 |
一般工业技术 | 29篇 |
冶金工业 | 16篇 |
原子能技术 | 2篇 |
自动化技术 | 26篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 4篇 |
2009年 | 9篇 |
2008年 | 11篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 6篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有159条查询结果,搜索用时 31 毫秒
1.
2.
Suniti Misra Mrinal K. Ghosh A. Choudhury Ashis K. Dutta Prasanta K. Pal Amitabha Ghosh 《Journal of the science of food and agriculture》1985,36(11):1193-1196
Fatty acids of the total lipids of flesh and hepatopancreas of Macoma sp. have been determined. The level of 20:5w3 (ca 17%), a biologically important fatty acid, was found to be considerably high. Other major component fatty acids were 16:0, 16:1, 18:1 and 22:4w6. High levels of 22:5w6 (8%), 22:5w3 (8%) and 22:6w3 (ca 15%) were found in flesh lipid. Nonsaponifiables were also high (28–30%). Alkyl ether acyl glycerols were found in flesh (1.3%) and hepatopancreas (3.8%). 相似文献
3.
4.
5.
A new equationE =E
0 (1 –bp)
n
has been derived semi-empirically to describe the porosity dependence of elastic properties of thermosetting polymers. The material constantb is defined as a pore distribution geometry factor and the other material constantn is dependent on pore geometry. The equation shows good agreement with the data on porous polyester and epoxy resins. 相似文献
6.
In situ synchrotron X-ray studies on copper-nickel 5 V Mn oxide spinel cathodes for Li-ion batteries
Partial substitution of Mn in lithium manganese oxide spinel materials by Cu and Ni greatly affects the electrochemistry and the cycle life characteristics of the cathode. Substitution with either metal or a combination of both metals in the spinel lattice structure reduces the 3.9-4.2 V potential plateaus associated with the conversion of Mn3+ to Mn4+. Higher potential plateau associated with oxidation of the substituted transition elements is also observed. These substituents also significantly alter the onset of Jahn-Teller distortions in the 3 V potential plateau. Synchrotron based in situ X-ray absorption (XAS) was used to determine the exact nature of the oxidation state changes in order to explain the overall observed capacities at different potential plateaus. The studies on LiCu0.5Mn1.5O4 show single phase behavior in the 4-5 V potential region with a good cycle life. Lower cycle life characteristic observed in cycling LiNi0.5Mn1.5O4 and LiNi0.25Cu0.25Mn1.5O4 versus Li metal are ascribed to coexistence of several phases in this potential region. However, LiCu0.5Mn1.5O4 shows onset of Jahn-Teller distortions in the 3 V potential plateau, in contrast to LiNi0.5Mn1.5O4 and LiNi0.25Cu0.25Mn1.5O4 cathode materials. 相似文献
7.
Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal
sperm plasma membrane. The lipids were identified as wax esters and 1-O-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/1H nuclear magnetic resonance spectral evidence. The membrane containedca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols
in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C14 to C22. The major fatty acids of the wax esters were 14∶0, 16∶0, 16∶1ω7, 18∶0 and 18∶1ω9. The fatty acids in alkyldiacylglycerol
were 16∶0, 18∶0, 22∶5ω3 and 22∶6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22∶6ω3) representing
30% of the total fatty acids. The alcohols of wax ester were all saturated with C20–C29 carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9′-enyl
glycerol ethers. 相似文献
8.
Mona Gupta Happy Mittal Parag Singla Amitabha Bagchi 《Electronic Commerce Research》2017,17(3):521-551
In this work we characterize the session-level behavior of users on an Indian mobile phone comparison shopping website. We also correlate the popularity of handset on various news sources to its popularity on the shopping website. There are three aspects to our study: data analysis, correlation between news sources of product information and popularity of a handset, and behavior prediction. We have used KL divergence to show that a time-homogeneous Markov chain is observed when the number of clicks varies from 5 to 30. Our results depict that Markov chain model does not hold in entirety for comparison shopping setting but tells us how far the Markov chain model holds for this setting. Our analysis corroborates intuition that increasing price leads to decrease in popularity. After the strong correlation between various variables and user behavior was found, we predict the users macro (the overall sales of handset) and micro behavior (whether a user will convert or exit the site) using Markov logic networks. Our predictive model validates the intuition that past browsing behavior is an important predictor for future behavior. Methodology of combining data analysis with machine learning is, in our opinion, a new approach to the empirical study of such data sets. 相似文献
9.
In human designer usage, symbols have a rich semantics, grounded on experience, which permits flexible usage — e.g. design ideation is improved by meanings triggered by contrastive words. In computational usage however, symbols are syntactic tokens whose semantics is mostly left to the implementation, resulting in brittle failures in many knowledge-based systems. Here we ask if one may define symbols in computational design as {label,meaning} pairs, as opposed to merely the label. We consider three questions that must be answered to bootstrap a symbol learning process: (a) which concepts are most relevant in a given domain, (b) how to define the semantics of such symbols, and (c) how to learn labels for these so as to form a grounded symbol. We propose that relevant symbols may be discovered by learning patterns of functional viability. The stable patterns are information-conserving codes, also called chunks in cognitive science, which relate to the process of acquiring expertise in humans. Regions of a design space that contain functionally superior designs can be mapped to a lower-dimensional manifold; the inter-relations of the design variables discovered thus constitute the chunks. Using these as the initial semantics for symbols, we show how the system can acquire labels for them by communicating with human designers. We demonstrate the first steps in this process in our baby designer approach, by learning two early grounded symbols, tight and loose. 相似文献
10.
With reference to a wide class of empirical and related likelihoods, we study priors which ensure approximate frequentist
validity of the posterior quantiles of a general parametric function. It is seen that no data-free prior entails such frequentist
validity but, at least for the usual empirical likelihood, a data-dependent prior serves the purpose. Accounting for the nonlinearity
of the parametric function of interest requires special attention in the derivation. A simulation study is seen to provide
support, in finite samples, to our asymptotic results. 相似文献