全文获取类型
收费全文 | 793篇 |
免费 | 45篇 |
专业分类
综合类 | 1篇 |
化学工业 | 213篇 |
金属工艺 | 8篇 |
机械仪表 | 11篇 |
建筑科学 | 36篇 |
矿业工程 | 2篇 |
能源动力 | 13篇 |
轻工业 | 140篇 |
水利工程 | 4篇 |
石油天然气 | 8篇 |
无线电 | 28篇 |
一般工业技术 | 88篇 |
冶金工业 | 216篇 |
原子能技术 | 6篇 |
自动化技术 | 64篇 |
出版年
2023年 | 7篇 |
2022年 | 17篇 |
2021年 | 41篇 |
2020年 | 24篇 |
2019年 | 24篇 |
2018年 | 21篇 |
2017年 | 22篇 |
2016年 | 21篇 |
2015年 | 14篇 |
2014年 | 22篇 |
2013年 | 45篇 |
2012年 | 35篇 |
2011年 | 36篇 |
2010年 | 38篇 |
2009年 | 42篇 |
2008年 | 38篇 |
2007年 | 40篇 |
2006年 | 36篇 |
2005年 | 22篇 |
2004年 | 30篇 |
2003年 | 19篇 |
2002年 | 21篇 |
2001年 | 16篇 |
2000年 | 9篇 |
1999年 | 21篇 |
1998年 | 14篇 |
1997年 | 21篇 |
1996年 | 19篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1976年 | 5篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1962年 | 1篇 |
排序方式: 共有838条查询结果,搜索用时 15 毫秒
61.
Denise Sato Yamashita Vinícius Amaral Armentano Manuel Laguna 《Journal of Scheduling》2007,10(1):67-76
We address a project scheduling problem with resource availability cost for which the activity durations are uncertain. The
problem is formulated within the robust optimization framework, where uncertainty is modeled via a set of scenarios. The proposed
solution method is based on the scatter search methodology and employs advanced strategies, such as dynamic updating of the
reference set, a frequency-based memory mechanism, and path relinking. A multistart heuristic was also developed and comparative
results are reported. The tradeoffs for risk-averse decision makers are discussed. 相似文献
62.
This article presents information on the development and validation of the Facial Expression Coding System (FACES; A. M. Kring & D. Sloan, 1991). Grounded in a dimensional model of emotion, FACES provides information on the valence (positive, negative) of facial expressive behavior. In 5 studies, reliability and validity data from 13 diverse samples, including students, psychiatric patients, and community adults, are presented, and results indicate that raters can reliably agree on instances of positive and negative expressive behavior. Validity studies indicate that FACES ratings are related in predictable ways to another observational coding system, facial muscle activity, individual-difference measures of expressiveness and personality, skin conductance, heart rate, and reports of experienced emotion. FACES can be a useful tool for assessing expressive behavior in a variety of contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
Giuseppe Curr Marco Camalleri Denise Calì Francesca Monforte Fortunato Neri 《Microelectronics Reliability》2007,47(4-5):798
A detailed study of the carrier trapping properties shown by the silicon/oxynitride/oxide gate layers in PowerVDMOS technologies is reported. A quantitative analysis of hole and electron trap densities versus the specific N2O based nitridation process, extracted from Fowler–Nordheim constant current stress kinetics, allows a deep understanding of the role played by those defects in the susceptibility of every nitrided layer. 相似文献
64.
Denise Bevilaqua Heloisa A. Acciari Fabiana A. Arena Assis V. Benedetti Cecílio S. Fugivara Germano Tremiliosi Filho Oswaldo Garcia Júnior 《Minerals Engineering》2009,22(3):254-262
In this work, the monitoring of the bacterial and chemical dissolution of bornite was evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS); the mineral surface was examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analysis of CV results allowed attributing the different peaks observed in both direct and reverse potential scanning to the oxidation of bornite to a secondary covellite and its reduction via different non stoichiometric copper sulphides intermediaries. EIS data for bornite were obtained in control medium up to 78 h of immersion, when a cellular suspension of A. ferrooxidans was added and the experiments continued up to a 192 h of test. The EIS response was different when bacteria were added in the beginning of the test or after some hours of immersion in acid solution. The experiments were performed in different cell configurations and a model of the electrode/electrolyte interface. The correspondent equivalent electrical circuit was used to fit impedance spectra for all studied conditions. A common equivalent circuit used for corrosion processes where anodic (degradation of the mineral) and cathodic (oxygen reduction) reactions occur in parallel, together film and biofilm formation was proposed. 相似文献
65.
Olver Mark E.; Preston Denise L.; Camilleri Joseph A.; Helmus Leslie; Starzomski Andrew 《Canadian Metallurgical Quarterly》2011,52(4):310
Although survey results seem to indicate an abundant interest among Canadian psychology graduate students in pursuing training in criminal justice psychology, the recruitment and retention of psychologists in the Correctional Service of Canada (CSC) has been of some concern. The present study is a 2008 survey of sites within CSC that provide opportunities for clinical psychology training with offender clientele. Survey findings demonstrated that a broad range of clinical psychology training opportunities were available across 16 sites. The most frequently cited barrier to providing training was lack of time by prospective trainers, and sites reported retaining relatively few of their trainees for subsequent psychologist positions. Information was also obtained regarding vacant psychologist positions across CSC regions. In light of survey findings, substantive discussion is devoted toward the issues of psychologist recruitment and retention in Canadian federal corrections, including a discussion of both potential and existing training initiatives. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
66.
Denise Fukumi Tsunoda Alex Alves Freitas Heitor Silv��rio Lopes 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2011,15(10):1897-1908
Proteins can be grouped into families according to some features such as hydrophobicity, composition or structure, aiming
to establish common biological functions. This paper presents MAHATMA—memetic algorithm-based highly adapted tool for motif
ascertainment—a system that was conceived to discover features (particular sequences of amino acids, or motifs) that occur
very often in proteins of a given family but rarely occur in proteins of other families. These features can be used for the
classification of unknown proteins, that is, to predict their function by analyzing their primary structure. Experiments were
done with a set of enzymes extracted from the Protein Data Bank. The heuristic method used was based on genetic programming
using operators specially tailored for the target problem. The final performance was measured using sensitivity, specificity
and hit rate. The best results obtained for the enzyme dataset suggest that the proposed evolutionary computation method is
effective in finding predictive features (motifs) for protein classification. 相似文献
67.
Denise Abatti M. Elisabete D. Zaniquelli Yassuko Iamamoto Ynara M. Idemori 《Thin solid films》1997,310(1-2):296-302
A synthetic iron ortho-substituted tetradecylpyridyl porphyrin was used to prepare Langmuir-Blodgett films. Better spreading at the gas-liquid interface was obtained for mixed films using palmitic acid in a 1:4 proportion. The minimum area per molecule from π-A curves for the pure porphyrin monolayers is correlated to the value obtained for the flat orientation of the porphyrinic center on the water surface, as determined by the CPK model. The fatty acid causes a decrease in the porphyrin minimum area per molecule. Single monolayer LB deposition gives a monomeric film without the presence of aggregates as attested by UV-visible spectra. The film was used in the heterogeneous catalysis of cyclohexene oxidation furnishing a yield two times higher than that obtained for the homogeneous system, using the same porphyrin amount and reagent ratio. The reaction was highly selective: only cyclohexene oxide was recorded as the product, confirming that the system is a good model for cytochrome P450. 相似文献
68.
Tate Denise G.; Kewman Donald G.; Maynard Frederick 《Canadian Metallurgical Quarterly》1990,35(4):211
Explored the appropriateness of the Brief Symptom Inventory (BSI) as a measure of psychological distress among 79 traumatic spinal cord injured (SCI) patients (aged 18–70 yrs) and emphasized the limitations of using the BSI as a replacement for the SCL-90—Revised (SCL-90—R). Ss' BSI scores were compared with a nonpatient normative group (N?=?974). Ss were significantly more psychologically distressed in somatization, depression, and phobic anxiety than the normative group. However, several somatization symptoms endorsed by these Ss are common physical effects of SCI rather than psychosomatic complaints. When comparing BSI and SCL-90—R scores of the same Ss, significant statistical differences were found with respect to the level of psychological distress being reported by each test. The BSI may not represent an equivalent abbreviated form of the SCL-90—R for the SCI population. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
69.
David L. Felten Suzanne Y. Felten John R. Sladek Mary D. Notter Sonia L. Carlson Denise L. Bellinger Stanley J. Wiegand 《Journal of microscopy》1990,157(3):271-283
Formaldehyde-induced and glyoxylic-acid-induced fluorescence histochemistry permits the tissue localization of catecholamines in the central nervous system (CNS) and peripheral nervous system (PNS), and in culture. Counterstains such as ethidium bromide provide excellent background identification of specific innervated regions in both the CNS and the periphery. Use of fluorescence histochemistry with immunocytochemistry can elucidate catecholamine-peptide relationships. Gelatin-ink perfusion used with fluorescence histochemistry permits the investigation of neuro-vascular relationships and documentation of vascular and parenchymal compartmentation of innervation. Combined use of fluorescence histochemistry and retrograde tracing methods demonstrates the specific cellular sources of innervation of target regions. Micropunch neurochemical analysis provides quantitative data for correlation with fluorescence histochemistry within a target region of innervation, and micro-spectrofluorometric analysis provides a semi-quantitative evaluation of the amount of fluorophore within a target region or within specific subcellular compartments such as the cell body or terminals. 相似文献
70.