全文获取类型
收费全文 | 244篇 |
免费 | 10篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 5篇 |
综合类 | 16篇 |
化学工业 | 16篇 |
金属工艺 | 2篇 |
机械仪表 | 5篇 |
建筑科学 | 22篇 |
矿业工程 | 6篇 |
能源动力 | 2篇 |
轻工业 | 12篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
无线电 | 6篇 |
一般工业技术 | 11篇 |
冶金工业 | 76篇 |
原子能技术 | 3篇 |
自动化技术 | 68篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 8篇 |
2011年 | 24篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 17篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1974年 | 2篇 |
1958年 | 2篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有259条查询结果,搜索用时 437 毫秒
251.
"Ss (N = 236) rated 20 foods as to preference using rating scales containing 2, 3, 5, 7, and 9 categories. Test reliability (summed ratings for each S) and rater reliability (summed ratings for each food) were computed for each scale. Test reliability was constant over the entire range of categories and was very similar to reliabilities found in another study. Rater reliability was constant from five to nine categories, but was slightly lower at two and slightly higher at three categories. It was concluded that test reliability is independent of the number of scale categories, and that rater reliability is relatively constant but" warrants further research. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
252.
Uri Zernik 《Machine Translation》1990,5(2):155-174
In this paper, which motivates lexical acquisition, we explain why existing lexicons are not complete and describe the impact of lexical gaps. We survey acquisition methods relative to their required resources and show that learning algorithms must be designed so that they rely on resources that are technologically available. We discuss in this light the availability and accessibility of machine-readable dictionaries and corpora. Finally we investigate the aspect of lexical semantics, addressing the question, What is the resource from which lexical semantics can be acquired? The answer is not clear because semantics is nowhere to be found explicitly. Thus, we resort to learning semantics by bootstrapping from secondary clues. 相似文献
253.
The categorical approach is proposed to the formalization of fuzzy graph grammars obtained as a result of generalization of
sequential graph grammars. This approach takes into consideration the basic types of fuzziness that arise in constructing
categories of fuzzy objects and describing transformations of fuzzy graphs generated by fuzzy sets. All the problems of undecidability
that are well known for Chomsky grammars are proved to hold true for fuzzy graph grammars.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 130–144, July–August 2006. 相似文献
254.
In their comment on K. Rothermund and D. Wentura (see record 2004-14313-001), A. G. Greenwald, B. A. Nosek, M. R. Banaji, and K. C. Klauer (see record 2005-09704-008) agreed that salience asymmetries can be a source of Implicit Association Test (IAT) effects. The authors applaud this conclusion but point to problems with the other points that Greenwald et al. made. The authors have difficulties understanding the nominal feature account that Greenwald et al. put forward and have doubts about the usefulness of their broad conception of the concept association. The authors also argue that existing evidence concerning the construct validity of the IAT does not allow one to discriminate between the association and the salience accounts. In addition, the new studies that were presented by Greenwald et al. do not provide insights into what the IAT measures because they are either irrelevant for a decision between the different accounts or contain methodological problems that prevent a meaningful interpretation in terms of the models. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
255.
256.
Characterization and normalization factors of abiotic resource depletion for life cycle impact assessment in China 总被引:7,自引:0,他引:7
The availability of resources for economic activities differs between regions, and the importance of the resources is consequently observed to be different within regions compared to a global scale. With the current situation in Chinese mining industry and its statistic characteristics, the characterization procedures of abiotic resource in life cycle impact assessment (LCIA) have demonstrated certain limita-tions in the Chinese materials industry. The aim of this paper is to propose new characterization and normalization factors for abiotic resource depletion categories such as metals and non-renewable en- ergy resources in a Chinese context. The actual production of abiotic resources calculated by a modi- fied model is compared to the reserve base in line with the new national standard to determine char- acterization factors in equivalence units, with antimony as the reference mineral. The normalization factors are based on the total base reserves of the most important minerals in China. A case study on primary magnesium production using the Pidgeon process is used to compare LCIA results for abiotic resource categories that are between current LCIA factors and the new Chinese factors. These factors not only reflect the importance of abiotic resource with respect to region-specific resource depletion, but also can compare with the global factors. 相似文献
257.
Optical information encryption and safety have aroused great attention since they are closely correlated to data protection and information safety. The development of multiple stimuli-response optical materials for constructing large-capacity information encryption and safety is very important for practical applications. Carbon dots (CDs) have many gratifying merits, such as polychromatic emission, diverse luminous categories, and stable physicochemical properties, and are considered as one of the most ideal candidates for information protection. Herein, carbon core, functional groups, solvents, and other crucial factors are reviewed for outputting polychromatic emission of multiple luminous categories. In particular, substrate engineering strategies have been emphasized for their critical role in yielding excellent optical features of multiple luminous categories. High-capacity information encryption and safety strategies are reviewed by relying on the rich optical properties of CDs, such as polychromatic emission, multiple luminous categories of fluorescence, afterglow, and upconversion, as well as external-stimuli-assisted optical changes. Some perspectives for preparing excellent CDs and further developing information security strategies are proposed. This review provides a good reference for the manipulation of polychromatic CDs and the development of next-generation information encryption and safety. 相似文献
258.
Haibo LIU Chengxin WANG Te LI Qile BO Kuo LIU Yongqing WANG 《Frontiers of Mechanical Engineering》2022,17(4):55
During the overall processing of thin-walled parts (TWPs), the guaranteed capability of the machining process and quality is determined by fixtures. Therefore, reliable fixtures suitable for the structure and machining process of TWP are essential. In this review, the key role of fixtures in the manufacturing system is initially discussed. The main problems in machining and workholding due to the characteristics of TWP are then analyzed in detail. Afterward, the definition of TWP fixtures is reinterpreted from narrow and broad perspectives. Fixture functions corresponding to the issues of machining and workholding are then clearly stated. Fixture categories are classified systematically according to previous research achievements, and the operation mode, functional characteristics, and structure of each fixture are comprehensively described. The function and execution mode of TWP fixtures are then systematically summarized and analyzed, and the functions of various TWP fixtures are evaluated. Some directions for future research on TWP fixtures technology are also proposed. The main purpose of this review is to provide some reference and guidance for scholars to examine TWP fixtures. 相似文献
259.