全文获取类型
收费全文 | 4370篇 |
免费 | 147篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 51篇 |
综合类 | 4篇 |
化学工业 | 985篇 |
金属工艺 | 59篇 |
机械仪表 | 53篇 |
建筑科学 | 248篇 |
矿业工程 | 33篇 |
能源动力 | 109篇 |
轻工业 | 239篇 |
水利工程 | 35篇 |
石油天然气 | 60篇 |
无线电 | 274篇 |
一般工业技术 | 764篇 |
冶金工业 | 899篇 |
原子能技术 | 47篇 |
自动化技术 | 664篇 |
出版年
2022年 | 64篇 |
2021年 | 86篇 |
2020年 | 53篇 |
2019年 | 70篇 |
2018年 | 71篇 |
2017年 | 104篇 |
2016年 | 87篇 |
2015年 | 89篇 |
2014年 | 104篇 |
2013年 | 296篇 |
2012年 | 159篇 |
2011年 | 213篇 |
2010年 | 151篇 |
2009年 | 146篇 |
2008年 | 192篇 |
2007年 | 186篇 |
2006年 | 153篇 |
2005年 | 166篇 |
2004年 | 111篇 |
2003年 | 145篇 |
2002年 | 111篇 |
2001年 | 92篇 |
2000年 | 64篇 |
1999年 | 77篇 |
1998年 | 110篇 |
1997年 | 83篇 |
1996年 | 82篇 |
1995年 | 54篇 |
1994年 | 53篇 |
1993年 | 53篇 |
1992年 | 45篇 |
1991年 | 39篇 |
1990年 | 58篇 |
1989年 | 57篇 |
1988年 | 47篇 |
1987年 | 55篇 |
1986年 | 38篇 |
1985年 | 51篇 |
1984年 | 45篇 |
1983年 | 42篇 |
1982年 | 42篇 |
1981年 | 34篇 |
1980年 | 29篇 |
1979年 | 41篇 |
1978年 | 35篇 |
1977年 | 31篇 |
1976年 | 52篇 |
1975年 | 31篇 |
1974年 | 33篇 |
1973年 | 42篇 |
排序方式: 共有4524条查询结果,搜索用时 15 毫秒
1.
2.
3.
Systematic assessment of anger among people with developmental disabilities has been lacking, especially for hospital inpatients. Reliability and validity of anger self-report psychometric scales were investigated with 129 male patients, mostly forensic. Anger prevalence and its relationship to demographic, cognitive, and personality variables and to hospital assaultive behavior were examined. High internal and intermeasure consistency, and some concurrent validity with staff ratings, were found. Retrospective validity regarding physically assaultive behavior in the hospital was obtained. Hierarchical regressions revealed that patient-reported anger was a significant predictor of assaults postadmission, controlling for age, length of stay, IQ, violence offense history, and personality variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Hannes Verlinde Martine De Cock Raymond Boute 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(3):679-684
As opposed to quantitative association rule mining, fuzzy association rule mining is said to prevent the overestimation of boundary cases, as can be shown by small examples. Rule mining, however, becomes interesting in large databases, where the problem of boundary cases is less apparent and can be further suppressed by using sensible partitioning methods. A data-driven approach is used to investigate if there is a significant difference between quantitative and fuzzy association rules in large databases. The influence of the choice of a particular triangular norm in this respect is also examined. 相似文献
5.
Values of D0 /δ and Q for grain-boundary diffusion, derived from published studies of normal grain growth in Al2 O3 , BeO, CaO, MgO, SiO2 , and CaSiO3 , are fit by the linear compensation equation log D0 /δ=0.03170Q -7.6792 (r2 =0.9384). Comparison of grain-boundary diffusion coefficients derived from grain growth in oxides with those obtained by direct experimental measurement suggests that the kinetics of normal grain growth are controlled by grain-boundary diffusion of oxygen. 相似文献
6.
In this paper we shall review the main appraches to nonmonotonic reasoning which we classify from the perspective of their underlying logical settings as classical, intuitionistic, three-valued/partial models, and conditional. We shall be placing special emphasis on some of the prominent approaches. We shall also give hints on potential future directions and emphasize that more theoretical work is still needed before a move to application is made. 相似文献
7.
Butler Emily A.; Egloff Boris; Wlhelm Frank H.; Smith Nancy C.; Erickson Elizabeth A.; Gross James J. 《Canadian Metallurgical Quarterly》2003,3(1):48
At times, people keep their emotions from showing during social interactions. The authors' analysis suggests that such expressive suppression should disrupt communication and increase stress levels. To test this hypothesis, the authors conducted 2 studies in which unacquainted pairs of women discussed an upsetting topic. In Study 1, one member of each pair was randomly assigned to (a) suppress her emotional behavior, (b) respond naturally, or (c) cognitively reappraise in a way that reduced emotional responding. Suppression alone disrupted communication and magnified blood pressure responses in the suppressors' partners. In Study 2, suppression had a negative impact on the regulators' emotional experience and increased blood pressure in both regulators and their partners. Suppression also reduced rapport and inhibited relationship formation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
There is widespread application of indicators to the assessment of environmental condition of streams. These indicators are intended for use by managers in making various comparative and absolute assessments and often have a role in resource allocation and performance assessment. Therefore, the problem of formally defining confidence in the results is important but difficult because the sampling strategies used are commonly based on a compromise between the requirements of statistical rigour and the pragmatic issues of access and resources. It is rare to see this compromise explicitly considered and consequently there is seldom quantification of the uncertainty that could affect the confidence a manager has in an indicator. In this paper, we present a method for quantitatively assessing the tradeoffs between sampling density and uncertainty in meeting various monitoring objectives. Assessments using judgement‐based representative reaches are shown to be unreliable; instead a sampling approach is recommended based on the random selection of measuring sites. A detailed dataset was collected along two streams in Victoria, Australia, and the effect of sampling density was assessed by subsampling from this dataset with precision related to the number of sites assessed per reach length and the intensity of the sampling at each site. The sampling scheme to achieve a given precision is shown to depend on the monitoring objective. In particular, three objectives were considered: (1) making a baseline assessment of current condition; (2) change detection; and (3) detection of a critical threshold in condition. Change detection is shown to be more demanding than assessing baseline condition with additional sampling effort required to achieve the same precision. Sampling to detect a critical threshold depends on nominating acceptable values of Type I and II error and the size of the effect to be detected. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
9.
This paper analyses the load influence on a d.c. drive motor servo system for all six degrees of freedom of industrial robots with an articulated configuration. Through the analyses, the analytical equations of total inertia and gravitation moments of an industrial robot servo system for external coordinate function were obtained. A mathematical model of an electro-mechanical industrial robot system was also developed. 相似文献
10.