全文获取类型
收费全文 | 147篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 19篇 |
金属工艺 | 6篇 |
机械仪表 | 2篇 |
建筑科学 | 17篇 |
矿业工程 | 2篇 |
能源动力 | 2篇 |
轻工业 | 10篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 20篇 |
一般工业技术 | 20篇 |
冶金工业 | 12篇 |
自动化技术 | 40篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 10篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有153条查询结果,搜索用时 31 毫秒
131.
Land use change and soil organic carbon dynamics 总被引:7,自引:0,他引:7
Pete Smith 《Nutrient Cycling in Agroecosystems》2008,81(2):169-178
Historically, soils have lost 40–90 Pg carbon (C) globally through cultivation and disturbance with current rates of C loss
due to land use change of about 1.6 ± 0.8 Pg C y−1, mainly in the tropics. Since soils contain more than twice the C found in the atmosphere, loss of C from soils can have
a significant effect of atmospheric CO2 concentration, and thereby on climate. Halting land-use conversion would be an effective mechanism to reduce soil C losses,
but with a growing population and changing dietary preferences in the developing world, more land is likely to be required
for agriculture. Maximizing the productivity of existing agricultural land and applying best management practices to that
land would slow the loss of, or is some cases restore, soil C. There are, however, many barriers to implementing best management
practices, the most significant of which in developing countries are driven by poverty. Management practices that also improve
food security and profitability are most likely to be adopted. Soil C management needs to considered within a broader framework
of sustainable development. Policies to encourage fair trade, reduced subsidies for agriculture in developed countries and
less onerous interest on loans and foreign debt would encourage sustainable development, which in turn would encourage the
adoption of successful soil C management in developing countries. If soil management is to be used to help address the problem
of global warming, priority needs to be given to implementing such policies. 相似文献
132.
Pete Sawyer 《Requirements Engineering》2013,18(2):105-106
133.
Pete Watt 《International journal of remote sensing》2013,34(16):5892-5904
Light detection and ranging (lidar) has been successfully used to describe a wide range of forest metrics at local scales. However, little research has tested the general applicability of this technology to describe commercially important stand dimensions, such as total stem volume (V), at national levels across broad environmental gradients. Using an extensive national data set covering the spatial extent of Pinus radiata plantation forests in New Zealand, the key objectives of this study were to (1) develop regression models to best describe V for P. radiata from lidar metrics and (2) investigate whether these relationships could be improved using coincident environmental and stand-level information. Development of relationships between lidar metrics and forest volume are of particular importance for P. radiata, as this species constitutes approximately 90% of the 1.8 Mha plantation resource. Using lidar mean height and the percentage of lidar ground returns, the initial model (model 1) accounted for 85% of the variance in V. Addition of stand stocking (number of stems ha?1), measured within the plots, to the model (model 2) significantly (p < 0.001) improved predictions, with R 2 increasing to 0.86 and the root mean square error declining from 80.1 m3 ha?1 to 71.6 m3 ha?1. For both models, partial responses show V to be most sensitive to lidar mean height, which was included in the model as a second-order polynomial. Although environmental variables are established determinants for V, their inclusion did not significantly improve either model 1 or 2. Residual values for both models showed little apparent bias when plotted against stand-level information or a wide array of environmental variables, supporting the general applicability of these relationships. 相似文献
134.
Random set framework for multiple instance learning 总被引:1,自引:0,他引:1
Multiple instance learning (MIL) is a technique used for learning a target concept in the presence of noise or in a condition of uncertainty. While standard learning techniques present the learner with individual samples, MIL alternatively presents the learner with sets of samples. Although sets are the primary elements used for analysis in MIL, research in this area has focused on using standard analysis techniques. In the following, a random set framework for multiple instance learning (RSF-MIL) is proposed that can directly perform analysis on sets. The proposed method uses random sets and fuzzy measures to model the MIL problem, thus providing a more natural mathematical framework, a more general MIL solution, and a more versatile learning tool. Comparative experimental results using RSF-MIL are presented for benchmark data sets. RSF-MIL is further compared to the state-of-the-art in landmine detection using ground penetrating radar data. 相似文献
135.
Chung-Yang ChenAuthor Vitae P. Pete ChongAuthor Vitae 《Journal of Systems and Software》2011,84(3):479-491
Project and teamwork training is recognized as an important aspect in software engineering (SE) education. Senior projects, which often feature industrial involvement, serve the function of a ‘capstone course’ in SE curricula, by offering comprehensive training in collaborative software development. Given the characteristics of student team projects and the social aspects of software development, instructional issues in such a course must include: how to encourage teamwork, how to formalize and streamline stakeholder participation, and how to monitor students’ work, as well as sustain their desired collaborative effort throughout the development. In this paper, we present an exploratory study which highlights a particular case and introduces the meetings-flow approach. In order to investigate how this approach could contribute to the project's results, we examined its quantitative benefits in relation to the development of the project. We also conducted focus group interviews to discuss the humanistic findings and educational effects pertaining to this approach. 相似文献
136.
Jon Whittle Pete Sawyer Nelly Bencomo Betty H. C. Cheng Jean-Michel Bruel 《Requirements Engineering》2010,15(2):177-196
Self-adaptive systems have the capability to autonomously modify their behavior at run-time in response to changes in their
environment. Self-adaptation is particularly necessary for applications that must run continuously, even under adverse conditions
and changing requirements; sample domains include automotive systems, telecommunications, and environmental monitoring systems.
While a few techniques have been developed to support the monitoring and analysis of requirements for adaptive systems, limited
attention has been paid to the actual creation and specification of requirements of self-adaptive systems. As a result, self-adaptivity
is often constructed in an ad-hoc manner. In order to support the rigorous specification of adaptive systems requirements,
this paper introduces RELAX, a new requirements language for self-adaptive systems that explicitly addresses uncertainty inherent
in adaptive systems. We present the formal semantics for RELAX in terms of fuzzy logic, thus enabling a rigorous treatment
of requirements that include uncertainty. RELAX enables developers to identify uncertainty in the requirements, thereby facilitating
the design of systems that are, by definition, more flexible and amenable to adaptation in a systematic fashion. We illustrate
the use of RELAX on smart home applications, including an adaptive assisted living system. 相似文献
137.
本文是有关介绍新型制冷剂专题的系列文章之二。第一篇文章回顾了R410A的发展史,介绍了R410A如何成为空调系统的新宠。本文将比较不同制冷剂的特性,并解释了全球越来越多的空调生产商倾向选择R410A的原因是在系统成本允许的条件下,他们不仅需要使效率更高,还要肩负环境保护的责任。上一篇文章阐述过,R22曾经是世界上使用最广泛的碳氟化合物制冷剂,而目前已出现了数种用以取代R22的候补产品,包括环保的含氢氟代烃(HFC)制冷剂-R134a,R410A和R407C。 相似文献
138.
Sutcliffe Alistair Sawyer Pete Stringer Gemma Couth Samuel Brown Laura J. E. Gledson Ann Bull Christopher Rayson Paul Keane John Zeng Xiao-jun Leroi Iracema 《Requirements Engineering》2020,25(1):1-20
Requirements Engineering - We report experience in requirements elicitation of domain knowledge from experts in clinical and cognitive neurosciences. The elicitation target was a causal model for... 相似文献
139.
Dye loss from unfixed dyed fabrics has been found to be insensitive to change in surfactant type or concentration. There was accompanying dye transfer to white fabric but this was reduced by Synperonic A7 in the case of fabrics dyed with CI Direct Green 26, due to solubilisation of the dye in nonionic micelles. The anionic surfactant, SDS, selectively displaced dye from fixed dyed fabrics, paralleling its behaviour with water soluble polymers. Similarly, dye loss was related to concentration of surfactant monomer, the effect increasing with SDS concentration up to its critical micelle concentration. Other anionic surfactants have been found to exhibit a similar trend, the effect increasing with their increasing surface activity. The commercial polymeric fixatives, Tinofix ECO and Indosol E50, were the most effective of those studied and the single-chain cationic surfactant, CTAB, was the least effective. 相似文献
140.
Sulfate Attack on Cement-Stabilized Sand 总被引:3,自引:0,他引:3
Raymond S. Rollings J. Pete Burkes Marian P. Rollings 《Canadian Metallurgical Quarterly》1999,125(5):364-372
A 3.5-km (2.2 mi) section of a road in Georgia developed unexpected transverse bumps within 6 months after construction. The source of the bumps appeared to be expansion within the cement-stabilized base course. Laboratory examination of samples from areas showing distress revealed the presence of ettringite, a calcium sulfoaluminate the formation of which can be accompanied by severe expansion. This expansive material was the probable cause of the volume changes causing the transverse bumps. The calcium and alumina needed to form ettringite were available from the portland cement and the stabilized soil's clay minerals. The source of the sulfur was identified as the well water that was mixed with the cement-stabilized base. Sulfate attack of cement-stabilized soils is a relatively infrequent problem, but it is highly destructive when it occurs. Currently, there are no firm criteria for identifying when sulfate attack of a cement-stabilized soil is a potential problem nor are there established methods of preventing the attack. 相似文献