全文获取类型
收费全文 | 4858篇 |
免费 | 326篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 25篇 |
综合类 | 5篇 |
化学工业 | 1504篇 |
金属工艺 | 28篇 |
机械仪表 | 89篇 |
建筑科学 | 181篇 |
矿业工程 | 6篇 |
能源动力 | 101篇 |
轻工业 | 1153篇 |
水利工程 | 39篇 |
石油天然气 | 27篇 |
无线电 | 182篇 |
一般工业技术 | 606篇 |
冶金工业 | 848篇 |
原子能技术 | 13篇 |
自动化技术 | 379篇 |
出版年
2024年 | 17篇 |
2023年 | 61篇 |
2022年 | 270篇 |
2021年 | 288篇 |
2020年 | 128篇 |
2019年 | 157篇 |
2018年 | 189篇 |
2017年 | 189篇 |
2016年 | 197篇 |
2015年 | 133篇 |
2014年 | 241篇 |
2013年 | 350篇 |
2012年 | 293篇 |
2011年 | 332篇 |
2010年 | 242篇 |
2009年 | 227篇 |
2008年 | 218篇 |
2007年 | 215篇 |
2006年 | 173篇 |
2005年 | 131篇 |
2004年 | 116篇 |
2003年 | 89篇 |
2002年 | 88篇 |
2001年 | 45篇 |
2000年 | 61篇 |
1999年 | 45篇 |
1998年 | 58篇 |
1997年 | 49篇 |
1996年 | 60篇 |
1995年 | 38篇 |
1994年 | 49篇 |
1993年 | 35篇 |
1992年 | 48篇 |
1991年 | 9篇 |
1990年 | 31篇 |
1989年 | 30篇 |
1988年 | 25篇 |
1987年 | 31篇 |
1986年 | 29篇 |
1985年 | 24篇 |
1984年 | 25篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1981年 | 27篇 |
1980年 | 10篇 |
1979年 | 17篇 |
1978年 | 11篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1975年 | 8篇 |
排序方式: 共有5186条查询结果,搜索用时 15 毫秒
1.
2.
Ana MRB Xavier Ana Paula M Tavares Margarida SM Agapito Dmitry V Evtuguin 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(12):1602-1608
BACKGROUND: A sequential batch reactor (SBR) was used for eucalypt kraft pulp effluent treatment with Trametes versicolor. A 23 full factorial design and response surface methodology were applied to optimise the batch fermentation conditions. Effluent concentration, culture medium and inoculum age were the factors selected for this study in order to optimise the reduction of chemical oxygen demand (COD). RESULTS: The presence of Trametes Defined Medium (TDM) in the fermentation was required to obtain a significant COD reduction. Experiments in the batch reactor confirmed, in general, the predicted results of optimisation developed from Erlenmeyer batch assays. The T. versicolor culture remained active during 42 days of study in the SBR, providing approximately 80% of COD reduction. CONCLUSION: Trametes versicolor may be considered as very promising for the biological treatment of effluents from kraft pulp mills in an SBR system instead of the activated sludge mixed cultures traditionally used. Copyright © 2008 Society of Chemical Industry 相似文献
3.
4.
5.
Stress in the parenting role has been found to be related to family functioning and parenting behavior. However, most research in this area has been conducted with clinical samples and has not compared parenting stress of mothers and fathers. In this study, 589 married couples with young children (12 to 60 months old) completed the Parenting Stress Index-Short Form (Abidin, 1990) and measures of child-rearing behaviors and attitudes, social support, and child behavior. The validity of Abidin's measure and theoretical model was tested, and results were mixed. Small effects were found for mothers and fathers, and these were moderated by child age and marital happiness. Stress as a normal consequence of parenting is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
This article describes the application, at the team and individual level, of findings from the positive psychology research. An overview of this research is presented focusing on several areas generally included in the positive psychology domain: flow, appreciative inquiry, the broaden and build theory, and other strategies for increasing the experience of positive emotions and the identification and deployment of strengths. The authors propose that these applications show promise in consulting psychology engagements and may have merit when utilized by practitioners themselves. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Do individual factors matter? A survey of scientists’ patenting in Portuguese public research organisations 总被引:1,自引:0,他引:1
Paula Susana Figueiredo Moutinho Margarida Fontes Manuel Mira Godinho 《Scientometrics》2007,70(2):355-377
This paper addresses scientists’ behaviour regarding the patenting of knowledge produced in universities and other public
sector research organisations (PSROs). Recent years have witnessed a rapid growth in patenting and licensing activities by
PSROs. We argue that the whole process depends to a certain extent on scientists’ willingness to disclose their inventions.
Given this assumption, we conduct research into individual behaviour in order to understand scientists’ views concerning the
patenting of their research results. Data from a questionnaire survey of Portuguese researchers from nine PSROs in life sciences
and biotechnology is presented and analysed and complemented with in-depth interviews. The results reveal that overall the
scientists surveyed show a low propensity to become involved in patenting and licensing activities, despite the fact that
the majority had no “ethical” objections to the disclosure of their inventions and the commercial exploitation of these. Perceptions
about the impacts of these activities on certain fundamental aspects of knowledge production and dissemination are however
divergent. This may account for the low participation levels. Furthermore, most scientists perceived the personal benefits
deriving from this type of activity to be low. Similarly, the majority also believed that there are many difficulties associated
with the patenting process and that they receive limited support from their organisations, which lack the proper competences
and structures to assist with patenting and licensing. 相似文献
8.
Williams Paula G.; Wasserman Michelle S.; Lotto Andrew J. 《Canadian Metallurgical Quarterly》2003,22(1):3
In 2 studies, the relation between measures of self-assessed health (SAH) and automatic processing of health-relevant information was investigated. In Study 1, 84 male and 86 female undergraduate students completed a modified Stroop task. Results indicated that participants with poorer SAH showed enhanced interference effects for illness versus non-illness words. In Study 2, 27 male and 30 female undergraduate students completed a self-referent encoding task. Results offered a conceptual replication and extension of Study 1 by confirming the specificity of the relation between SAH measures and automatic processing of health (vs negative or positive general trait) information. These studies provide evidence that individual differences in SAH are reflected in schematic processing of health-relevant information. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
X-ray photoelectron spectroscopy (XPS) applied to the study of fluorinated polymer surfaces presents several problems related both to peak assignment and to degradation. In this work, we analyse extensively the question of XPS peak assignments in this kind of surfaces. We conclude that in this kind of surfaces using binding energy differences between fluorine and carbon is better than using absolute binding energies. Also a useful relation between fluorine photoelectron energy vs. polymer composition expressed through the atomic ratio fluorine/carbon (F/C) was found. A protocol for data treatment is proposed and applied to a XPS study of the degradation induced by X-ray on high-density polyethylene surfaces modified by direct fluorination. Results obtained for the degradation, namely the atomic ratio F/C obtained by two different methods, combined with angle resolved X-ray photoelectron spectroscopy (ARXPS) were used to study the fluorine concentration profile in depth, producing self-consistent results. 相似文献
10.
Myers Mark G.; MacPherson Laura; McCarthy Denis M.; Brown Sandra A. 《Canadian Metallurgical Quarterly》2003,15(2):163
The goal of the present studies was to construct and validate a short form of the 50-item Smoking Consequences Questionnaire (SCQ; T. H. Brandon & T. B. Baker, 1991), a measure of smoking outcome expectancies. In Study 1, a 21-item short form (S-SCQ) was derived from a sample of 107 young adults previously treated for substance abuse. In Study 2, the measure was cross-validated on 125 adolescents in treatment for substance abuse. Confirmatory factor analyses revealed good model fit and factorial invariance for the 4 S-SCQ subscales across both samples. Validation analyses on each sample found that subscale scores generally correlated significantly with smoking-related variables. The present studies provide initial evidence for the utility of the S-SCQ when used with young adults and adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献