全文获取类型
收费全文 | 13072篇 |
免费 | 1179篇 |
国内免费 | 407篇 |
专业分类
电工技术 | 1770篇 |
技术理论 | 2篇 |
综合类 | 1013篇 |
化学工业 | 768篇 |
金属工艺 | 260篇 |
机械仪表 | 1128篇 |
建筑科学 | 2178篇 |
矿业工程 | 597篇 |
能源动力 | 309篇 |
轻工业 | 387篇 |
水利工程 | 474篇 |
石油天然气 | 404篇 |
武器工业 | 301篇 |
无线电 | 1087篇 |
一般工业技术 | 851篇 |
冶金工业 | 920篇 |
原子能技术 | 75篇 |
自动化技术 | 2134篇 |
出版年
2024年 | 40篇 |
2023年 | 121篇 |
2022年 | 390篇 |
2021年 | 504篇 |
2020年 | 426篇 |
2019年 | 278篇 |
2018年 | 281篇 |
2017年 | 365篇 |
2016年 | 465篇 |
2015年 | 427篇 |
2014年 | 1170篇 |
2013年 | 901篇 |
2012年 | 1132篇 |
2011年 | 1192篇 |
2010年 | 824篇 |
2009年 | 884篇 |
2008年 | 688篇 |
2007年 | 804篇 |
2006年 | 713篇 |
2005年 | 574篇 |
2004年 | 489篇 |
2003年 | 464篇 |
2002年 | 399篇 |
2001年 | 265篇 |
2000年 | 175篇 |
1999年 | 129篇 |
1998年 | 83篇 |
1997年 | 96篇 |
1996年 | 75篇 |
1995年 | 57篇 |
1994年 | 36篇 |
1993年 | 46篇 |
1992年 | 43篇 |
1991年 | 18篇 |
1990年 | 15篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1982年 | 4篇 |
1979年 | 6篇 |
1974年 | 4篇 |
1968年 | 3篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1961年 | 3篇 |
1960年 | 2篇 |
1959年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Anna Gielas 《Centaurus; international magazine of the history of science and medicine》2020,62(1):38-53
Mainly known for its links to the periodical market and radical politics, this article recontextualizes the editorship of William Nicholson (1753–1815) in terms of its roots in the metropolitan natural philosophical circles of the second half of the 18th century as well as its impact on experimenters and men of science after 1797. The article argues that Nicholson's editorship of the Journal of Natural Philosophy, Chemistry, and the Arts was a means to expand his philosophical significance among natural philosophers at home and abroad—and was, in fact, a form of epistemological subversion that challenged the “Banksian Learned Empire.” 相似文献
3.
As suggested by the uncanny valley hypothesis, robots that resemble humans likely elicit feelings of eeriness. Based on the psychological model of meaning maintenance, we expected that the uncanny valley experience could be mitigated through a fictional story, due to the meaning-generating function of narratives. A field experiment was conducted, in which 75 participants interacted with the humanlike robot Telenoid. Prior to the interaction, they either read a short story, a non-narrative leaflet about the robot, or they received no preliminary information. Eeriness ratings were significantly lower in the science fiction condition than in both other conditions. This effect was mediated by higher perceived human-likeness of the robot. Our findings suggest that science fiction may provide meaning for otherwise unsettling future technologies. 相似文献
4.
5.
6.
Aircraft maintenance organisation is a complex socio-technical setup, where human factors influence the quality of aircraft maintenance service. Maintenance service quality is assessed based on the commitment of management and its ability to provide suitable facility, tools, spares and manpower supported with comfortable environment and maintenance procedures. Assessment of the service quality of the aircraft maintenance organisation is a complex process. Airlines, regulators, insurance companies and other agencies need decision support system, to assess the performance of a maintenance organisation. This paper provides criteria and scientific approach for assessing the maintenance organisation; it presents a methodology of applying Analytical Hierarchy Process to prioritise the key functions and to rank the maintenance organisations under study. The study has established that maintenance service quality in airline is directly correlated to its fleet size. 相似文献
7.
H.C. Weigele L. Gygax A. Steiner B. Wechsler J.-B. Burla 《Journal of dairy science》2018,101(3):2370-2382
Lameness is one of the most prevalent diseases affecting the welfare of cows in modern dairy production. Lameness leads to behavioral changes in severely lame cows, which have been investigated in much detail. For early detection of lameness, knowledge of the effects of moderate lameness on cow behavior is crucial. Therefore, the behavior of nonlame and moderately lame cows was compared on 17 Swiss dairy farms. On each farm, 5 to 11 nonlame (locomotion score 1 of 5) and 2 to 7 moderately lame (locomotion score 3 of 5) cows were selected for data collection in two 48-h periods (A, B) separated by an interval of 6 to 10 wk. Based on visual locomotion scoring, 142 nonlame and 66 moderately lame cows were examined in period A and 128 nonlame and 53 moderately lame cows in period B. Between these 2 periods, the cows underwent corrective hoof trimming. Lying behavior, locomotor activity, and neck activity were recorded by accelerometers (MSR145 data logger, MSR Electronics GmbH, Seuzach, Switzerland), and feeding and rumination behaviors by noseband sensors (RumiWatch halter, ITIN + HOCH GmbH, Liestal, Switzerland). Furthermore, visits to the brush and the concentrate feeder, and the milking order position were recorded. In comparison with nonlame cows, moderately lame cows had a longer lying duration, a longer average lying bout duration, and a greater lateral asymmetry in lying duration. Average locomotor activity, locomotor activity during 1 h after feed delivery or push-ups, and average neck activity were lower in moderately lame cows. Eating time and the number of eating chews (jaw movements) were reduced in moderately lame compared with nonlame cows, whereas no effect of moderate lameness was evident for ruminating time, number of ruminating chews and boluses, and average number of ruminating chews per bolus. Moderately lame cows visited the concentrate feeder and the brush less frequently, and they were further back in the milking order compared with nonlame cows. In conclusion, nonlame and moderately lame cows differed in a biologically relevant way in many of the behavioral variables investigated in this study. Therefore, the use of these behavioral changes seems to be promising to develop a tool for early lameness detection. 相似文献
8.
以亚欧海底光缆S2段为例,介绍亚欧海底光缆远供电源(PFE)的供电方式,以及其在正常运行时和故障维修时的维护管理方法。探讨在实际维护中如何贯彻落实及灵活运用系统联合维护文档,总结适合中国国情的远供电源维护经验,确保亚欧海底光缆远供电源安全稳定运行。 相似文献
9.
A review of the literature on the impact of sexual contacts between adults and boys reveals the existence of two principal outcomes: 1) some participants develop various disorders once in adulthood, such as behavioural problems, sexual disorders, or personality problems; 2) some participants do not present with any major disorders in the long run. These different outcomes may be associated with several moderating variables related to the sexual contacts, such as the level of coercion at the time of these contacts, the bond between the child and the adult, or the context of the sexual relation. However, the conclusions relating to the relations between early sexual contacts with adults and subsequent problems of adaptation in adulthood are difficult to determine. This is because of various methodological problems associated with relevant studies (i.e., definition of these contacts, nature of the sample, method evaluation, statistical analyses). In this article, we propose certain avenues of research that may help clarify this problem. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Research and Development of a Network—Based Intelligent Maintenance Information System 总被引:1,自引:0,他引:1
ZANGTie-gang YANGMing-zhong GUOShun-sheng 《国际设备工程与管理》2003,8(2):74-79
A maintenance information system is an important part of equipment management.An intelli-gent maintenance information system(IMIS)is a synthesis of network technology,information technology and intelligent technology.The IMIS in used to finish flexible maintenance decision-making and fast main-tenance planning,which helps enterprises to effectively reduce maintenance cost and increase working effi-ciency.Because the IMIS integrates advanced technologies,its performance is better than a traditional one.The difference between an IMIS and a traditional maintenance information system,and the functions,struc-ture,important realizations,and application of an IMIS are discussed in this paper. 相似文献