全文获取类型
收费全文 | 429篇 |
免费 | 15篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 137篇 |
金属工艺 | 3篇 |
机械仪表 | 4篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 5篇 |
轻工业 | 88篇 |
水利工程 | 2篇 |
无线电 | 20篇 |
一般工业技术 | 59篇 |
冶金工业 | 75篇 |
原子能技术 | 1篇 |
自动化技术 | 38篇 |
出版年
2023年 | 2篇 |
2022年 | 14篇 |
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 4篇 |
2014年 | 14篇 |
2013年 | 24篇 |
2012年 | 13篇 |
2011年 | 31篇 |
2010年 | 26篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 22篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1995年 | 2篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1966年 | 3篇 |
1961年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有444条查询结果,搜索用时 15 毫秒
81.
Cacioppo John T.; Berntson Gary G.; Lorig Tyler S.; Norris Catherine J.; Rickett Edith; Nusbaum Howard 《Canadian Metallurgical Quarterly》2003,85(4):650
Developments within the neurosciences, cognitive sciences, and social sciences have contributed to the emergence of social neuroscience. Among the most obvious contemporary developments are brain-imaging procedures such as functional magnetic resonance imaging. The authors outline a set of first principles designed to help make sense of brain-imaging research within the fields of cognitive and social neuroscience. They begin with a principle few would debate--that social cognition, emotion, and behavior involve the brain--but whose implications might not be entirely obvious to those new to the field. The authors conclude that (a) complex aspects of the mind and behavior will benefit from yet a broader collaboration of neuroscientists, cognitive scientists, and social scientists, and (b) social psychologists bring important theoretical, methodological, and statistical expertise to this interdisciplinary enterprise. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
82.
83.
84.
Octavio Olivares-Xometl Edith Álvarez-Álvarez Natalya Victorovna Likhanova Irina Victorovna Lijanova Raquel E. Hernández-Ramírez 《Journal of Adhesion Science and Technology》2018,32(10):1092-1113
A novel class of four new-free-halide-ionic liquids (ILs) derived from ammonium was synthesized and characterized via spectroscopic methods such as 1H NMR and 13C NMR. The synthesized compounds were evaluated as corrosion inhibitors (CIs) of API 5L X60 steel in 1 M sulfuric acid by means of the potentiodynamic polarization and weight loss techniques. The results confirmed that the inhibition efficiency displayed by the four ILs is a function of their concentration and molecular structure. The obtained inhibition efficiency (η) ranged from 51 to 89%, confirming that the new class of ILs is good for corrosion inhibition purposes. The analysis of the potentiodynamic results showed that these compounds inhibit the corrosion of steel, classifying them as mixed-type CIs. The adsorption process of these new CIs on the API 5L X60 steel surface, which obeyed the Langmuir isotherm, was found to be physical and chemical. The SEM and EDX analyses confirmed the protection of steel in the corrosive medium. 相似文献
85.
Zack Fitzsimmons Edith Hemaspaandra Lane A. Hemaspaandra 《Annals of Mathematics and Artificial Intelligence》2016,77(3-4):159-189
Do runoff elections, using the same voting rule as the initial election but just on the winning candidates, increase or decrease the complexity of manipulation? Does allowing revoting in the runoff increase or decrease the complexity relative to just having a runoff without revoting? For both weighted and unweighted voting, we show that even for election systems with simple winner problems the complexity of manipulation, manipulation with runoffs, and manipulation with revoting runoffs are independent. On the other hand, for some important, well-known election systems we determine what holds for each of these cases. For no such systems do we find runoffs lowering complexity, and for some we find that runoffs raise complexity. Ours is the first paper to show that for natural, unweighted election systems, runoffs can increase the manipulation complexity. 相似文献
86.
Edith Hemaspaandra Lane A. Hemaspaandra Jörg Rothe 《Autonomous Agents and Multi-Agent Systems》2017,31(5):1055-1076
Previous work on voter control, which refers to situations where a chair seeks to change the outcome of an election by deleting, adding, or partitioning voters, takes for granted that the chair knows all the voters’ preferences and that all votes are cast simultaneously. However, elections are often held sequentially and the chair thus knows only the previously cast votes and not the future ones, yet needs to decide instantaneously which control action to take. We introduce a framework that models online voter control in sequential elections. We show that the related problems can be much harder than in the standard (non-online) case: For certain election systems, even with efficient winner problems, online control by deleting, adding, or partitioning voters is \(\mathrm {PSPACE}\)-complete, even if there are only two candidates. In addition, we obtain (by a new characterization of coNP in terms of weight-bounded alternating Turing machines) completeness for \({\mathrm {coNP}}\) in the deleting/adding cases with a bounded deletion/addition limit, and we obtain completeness for \({\mathrm {NP}}\) in the partition cases with an additional restriction. We also show that for plurality, online control by deleting or adding voters is in \({\mathrm {P}}\), and for partitioning voters is \({\mathrm {coNP}}\)-hard. 相似文献
87.
Thomas A. Foglia Edith J. Conkerton Philip E. Sonnet 《Journal of the American Oil Chemists' Society》1995,72(11):1275-1279
A modified procedure for the regiospecific analysis of triacylglycerols (TAG) with a 1,3-specific lipase is described. After
partial lipase hydrolysis of the triacylglycerol, the released free fatty acids (FFA) and 1,2(2,3)-diacylglycerols (DAG) were
isolated by thin-layer chromatography (TLC) and converted to fatty acid methyl esters (FAME). The FAME were analyzed by gas-liquid
chromatography (GLC). The 1,3-specific lipases used in this study included supported preparations from strains ofMucor miehei andRhizopus oryzae. The method also was applied to the regiospecific analyses of tung nut and Chinese melon seed oil triacyglycerols, both of
which contain high proportions of α-elaeostearic acid. The TAG composition of the oils was substantiated in parallel analysis
of the oils by highperformance liquid chromatography with chemical ionization mass spectrometric detection of intact TAG. 相似文献
88.
Wilmanns Matthias; Schlagenhauf Edith; Fol Bruno; Jansonius Johan N 《Protein engineering, design & selection : PEDS》1990,3(3):173-180
The recombinant synthase domain of the bifunctional enzyme N-(5'-phosphoribosyl)anthranilateisomerase:indole-3-glycerol-phosphate synthase from Escherichiacoli has been crystallized, and the structure has been solvedat 4 Å resolution. Two closely related crystal forms grownfrom ammonium sulphate diffract to 2 Å resolution. Oneform (space group R32, a = 163 Å, = 29.5°) containsthe unliganded synthase domain; the second crystal form (spacegroup P6322, a = 144 Å, c = 158 Å) is co-crystallizedwith the substrate analogue N-(5'-phosphoribit-1-yl)anthranilate.The structure of the synthaseinhibitor complex has beensolved by the molecular replacement method. This achievementrepresents the first successful use of a (ß)g-barrelmonomer as a trial model. The recombinant synthase domain associatesas a trimer in the crystal, the molecules being related by apseudo-crystallographic triad. The interface contacts betweenthe three domains are mediated by those residues that are alsoinvolved in the domain interface of the bifunctional enzyme.This system provides a model for an interface which is usedin both intermolecular and intramolecular domain contacts. 相似文献
89.
90.
The shield that never was: Societies with single-peaked preferences are more open to manipulation and control 总被引:1,自引:0,他引:1
Much work has been devoted, during the past 20 years, to using complexity to protect elections from manipulation and control. Many “complexity shield” results have been obtained—results showing that the attacker’s task can be made NP-hard. Recently there has been much focus on whether such worst-case hardness protections can be bypassed by frequently correct heuristics or by approximations. This paper takes a very different approach: We argue that when electorates follow the canonical political science model of societal preferences the complexity shield never existed in the first place. In particular, we show that for electorates having single-peaked preferences, many existing NP-hardness results on manipulation and control evaporate. 相似文献