全文获取类型
收费全文 | 639篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
化学工业 | 70篇 |
金属工艺 | 21篇 |
机械仪表 | 1篇 |
建筑科学 | 62篇 |
矿业工程 | 1篇 |
能源动力 | 7篇 |
轻工业 | 68篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 46篇 |
一般工业技术 | 79篇 |
冶金工业 | 195篇 |
原子能技术 | 3篇 |
自动化技术 | 77篇 |
出版年
2022年 | 12篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 13篇 |
2018年 | 20篇 |
2017年 | 16篇 |
2016年 | 13篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 49篇 |
2012年 | 21篇 |
2011年 | 31篇 |
2010年 | 24篇 |
2009年 | 32篇 |
2008年 | 29篇 |
2007年 | 19篇 |
2006年 | 19篇 |
2005年 | 13篇 |
2004年 | 9篇 |
2003年 | 12篇 |
2002年 | 16篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 13篇 |
1998年 | 37篇 |
1997年 | 24篇 |
1996年 | 15篇 |
1995年 | 20篇 |
1994年 | 13篇 |
1993年 | 18篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 4篇 |
1955年 | 3篇 |
1954年 | 2篇 |
排序方式: 共有646条查询结果,搜索用时 0 毫秒
1.
2.
T. M. Holden J. W. L. Pang R. A. Holt 《Metallurgical and Materials Transactions A》2002,33(3):749-755
The development of the understanding of the intergranular stresses in ZIRCALOY-2 is reviewed. Neutron diffraction measurements
of the intergranular strains were made on rod-textured material and highly textured plate. The elastoplastic self-consistent
(EPSC) model provides a sound theoretical foundation for our understanding of the behavior. The strain response of ZIRCALOY-2
to applied tensile stress is well described for two very different textures with the same slip and hardening parameters. It
is almost certain that tensile twinning is the explanation for the response to compressive stress and rolling that is, as
yet, incompletely understood.
This article is based on a presentation made in the symposium entitled “Defect Properties and Mechanical Behavior of HCP Metals
and Alloys” at the TMS Annual Meeting, February 11–15, 2001, in New Orleans, Louisiana, under the auspices of the following
ASM committees: Materials Science Critical Technology Sector, Structural Materials Division, Electronic, Magnetic & Photonic
Materials Division, Chemistry & Physics of Materials Committee, Joint Nuclear Materials Committee, and Titanium Committee. 相似文献
3.
Holden Ronald R.; Woermke Christina; Fekken G. Cynthia 《Canadian Metallurgical Quarterly》1993,25(1):1
Evaluated the effects of increasing scale reliability and of priming dimensional activation on the construct validity of personality test item differential response latencies. 93 undergraduates were computer-administered items from the 3 lengthened scales of the Personality Research Form. Findings show that differential response latencies can demonstrate remarkably strong evidence for their construct validity. In addition, the priming of personality traits may enhance the construct validity of their corresponding differential response latencies. Results support a model of test item responding where differential item response latencies reflect the interaction of an individual's schema with test item content. (French abstract) (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
4.
Disguise and the structured self-report assessment of psychopathology: I. An analogue investigation.
Explored the utility of disguise in structured self-report assessments of psychopathology in 3 experiments with 370 university students. Exp I used items from the Basic Personality Inventory (BPI); Exp II used the BPI, the Desirability scale of the Personality Research Form—Form E, and 4 criterion measures; and Exp III used 2 of the criterion measures and the BPI. Data indicate that under normal test-taking circumstances, the use of disguised test items was not advantageous. This relationship, however, was moderated by a number of dimensional parameters. When faking response sets in terms of desirability was induced, the use of disguised test item content was not useful. Data are interpreted in terms of the various strategies of test construction underlying the assessment of psychopathology. Results support a rational strategy of test construction emphasizing the use of relevant test item content. It is concluded that, in structured self-report assessments, the most valid results may be obtained through the use of direct questions with cooperative test respondents. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Dunham M.E. Light M. Holden D.N. 《Antennas and Propagation, IEEE Transactions on》1995,43(10):1017-1021
Helical antennas are popular and well characterized for CW frequency domain performance. Renewed interest in time-domain applications of electromagnetics, such as impulse radar, makes accurate time-domain data on broad-band antennas desirable. Although the principal endfire helix radiation mode has been extensively studied in the frequency domain, other modes important in pulse operation are poorly characterized, making a total Fourier transform approach difficult. We have performed impulse tests on helices with two to five turns, establishing novel features of the response and confirming some aspects of frequency domain data. Quick comparisons to time and frequency-domain modeling codes indicate good correspondence of gross features. Successful octave band-pulse operation was achieved, and a few features of helix pulse response invite further investigation 相似文献
6.
Spheroidization experiments were made on a medium- carbon AISI 4037 steel, using both intercritical and subcritical annealing
cycles. The results indicate that in the subcritical cycle the spheroidization occurred much more quickly than expected, so
that shorter times were sufficient to achieve high formability. On the other hand, the hardness dropped faster in the intercritical
cycle. Although more work needs to be done, these results suggest that using a subcritical spheroidization process instead
of an intercritical process could achieve considerable savings in time, energy, and cost. 相似文献
7.
Dennis J. O’Brien Gerard E. Senske 《Journal of the American Oil Chemists' Society》1994,71(9):947-950
Utilization of lipids containing eicosapentaenoic acid (EPA) produced by microorganisms requires processes for their efficient
recovery from microbial cells. Recovery of EPA from mycelia of the fungusPythium irregulare by solvent extraction with hexane-isopropanol (HIP) in a pilot-plant colloid mill was investigated. Extraction efficiencies
of 96% for lipid and EPA were achieved with a 3∶2 (vol/vol) HIP mixture by milling wet, filtered mycelia for 5 min at a solvent/dry
solids ratio of 100 L/kg. The process yielded a crude extract that contained up to 96% lipid and an EPA content as high as
24% (with no selectivity for EPA). 相似文献
8.
Wayne O’Brien Author Vitae 《Journal of Systems and Software》2008,81(11):1997-2013
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them. 相似文献
9.
Hierarchical classification of protein function with ensembles of rules and particle swarm optimisation 总被引:1,自引:1,他引:0
Nicholas Holden Alex A. Freitas 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(3):259-272
This paper focuses on hierarchical classification problems where the classes to be predicted are organized in the form of
a tree. The standard top-down divide and conquer approach for hierarchical classification consists of building a hierarchy
of classifiers where a classifier is built for each internal (non-leaf) node in the class tree. Each classifier discriminates
only between its child classes. After the tree of classifiers is built, the system uses them to classify test examples one
class level at a time, so that when the example is assigned a class at a given level, only the child classes need to be considered
at the next level. This approach has the drawback that, if a test example is misclassified at a certain class level, it will
be misclassified at deeper levels too. In this paper we propose hierarchical classification methods to mitigate this drawback.
More precisely, we propose a method called hierarchical ensemble of hierarchical rule sets (HEHRS), where different ensembles
are built at different levels in the class tree and each ensemble consists of different rule sets built from training examples
at different levels of the class tree. We also use a particle swarm optimisation (PSO) algorithm to optimise the rule weights
used by HEHRS to combine the predictions of different rules into a class to be assigned to a given test example. In addition,
we propose a variant of a method to mitigate the aforementioned drawback of top-down classification. These three types of
methods are compared against the standard top-down hierarchical classification method in six challenging bioinformatics datasets,
involving the prediction of protein function. Overall HEHRS with the rule weights optimised by the PSO algorithm obtains the
best predictive accuracy out of the four types of hierarchical classification method. 相似文献
10.
With the proliferation of macroergonomic field research, it is time to carefully examine how such research should be managed and implemented. We argue that the importance of attending to high-quality implementation of field research is equal to that of methodological rigor. One way to systematically manage the implementation process is to adopt a change management framework, wherein the research project is conceptualized as an instance of organization-level change. Consequently, principles for successful organization-level change from the literature on change management can be used to guide successful field research implementation. This paper briefly reviews that literature, deriving 30 principles of successful change management, covering topics such as political awareness, assembling the change team, generating buy-in, and management support. For each principle, corresponding suggestions for macroergonomic field research practice are presented. We urge other researchers to further develop and adopt frameworks that guide the implementation of field research. 相似文献