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排序方式: 共有191条查询结果,搜索用时 15 毫秒
1.
Luciana Sciascia Selene Casella Giuseppe Cavallaro Giuseppe Lazzara Stefana Milioto Francesco Princivalle Filippo Parisi 《Ceramics International》2019,45(2):2751-2759
Green composites for environmental applications were successfully prepared by intercalation of the biosurfactant Quillaja saponin onto montmorillonite mineral clay on varying pH and surfactant/clay ratio. Equilibrium adsorption isotherms were constructed and the system was characterized by performing TGA and XRD analyses.The efficiency of the surfactant-modified clay in the removal of the organic content present in olive mill wastewaters (OMW) was evaluated by means of spectrophotometric measurements. The interest for this cogent issue comes from the consideration that, despite their high pollutant content, OMW can be considered as a potential resource of several organic compounds which can be recovered for a wide array of pharmaceutical and industrial applications. Two different strategies were proposed. In the first one, dried surfactant/clay hybrids were added to the batch samples under continuous stirring, while in the second alternative approach the organoclays were packed in chromatography column filled with multiple alternate layers of sand and organoclay.These studies revealed the efficacy of the methods used and suggested that the modification of the montmorillonite clay substrate significantly improves the performance of the clay. 相似文献
2.
重塑矿山工业景观规划实验(之二)——兖矿集团兴隆庄煤矿采空区重建规划设计研究 总被引:1,自引:0,他引:1
我国能源结构以煤炭为主的格局短期内不会改变.煤炭生产造成地表塌陷的采空区日益扩大,极大地消耗着我国形势本已严峻的土地资源.一般来说,采空区的利用就是土地复垦、养鱼、绿化等.该文研究采取一定技术措施,利用煤矸石填筑采煤塌陷区作为建筑用地,造基建房,不仅可减少煤矸石污染、占地问题,同时解决采空区内村庄的就地安置难题,变采空区为居住用地,村民不用搬迁.一举多得,为解决兖州矿区的可持续发展、重建矿区生态环境提供了一条重要的技术途径. 相似文献
3.
Stephen Owen 《Landscape Research》2005,30(1):57-79
The notion that English hill towns can be identified as a particular type of settlement is reinforced and a systematic analysis of the characteristics that contribute to their identity in the wider landscape is undertaken. Fourteen towns that meet the working definition of an English hill town are examined in terms of four sets of characteristics that constitute their distinctive features: the continuing imprint of their origins, location and early functions; the influence of natural physical features on their founding and subsequent development; their morphological form; and the visual characteristics that are the medium through which their identity is mainly experienced — pre-eminent amongst these are a town's visual profile, its figure - ground relationship with the landscape, and its skyline. Groups of hill towns with consistent characteristics are identified, including 'classic' English hill towns. While the analysis is not directed explicitly towards the development and implementation of planning policy, the fuller understanding of hill towns gained through the analysis should enrich the policy process. 相似文献
4.
义乌市鸡鸣山广场规划顺应地形,把鸡鸣山广场主体分成多个高度不一、尺度较小的分区广场,并通过小尺度空间的穿插与交融,形成与城市整体空间体系相匹配的大尺度空间,采用延山引水、营造绿色的生态环境空间、营造丰富的视觉效果等措施,把丘陵地貌的劣势变为优势。 相似文献
5.
Nainital City of Kumaun Lesser Himalaya is prone to mass wasting processes during monsoon season, which mischievously triggers the hill slope instability in this region. Slate, dolomitic limestone, silty sandstone and rhythmite of the Krol Formation are the main rock types. The present study focuses on the investigation of slope stability in the region in terms of potential seismicity and landslide. Geological and geotechnical mapping indicates that the major portion of the area is characterized by slope wash materials and buildings. The combination of 3–4 joint sets with one random joint is the main structure at outcrops. The major geological structures of this area are Nainital lake fault passing from the center of the lake, Main Boundary Thrust at SW, and Khuriya Fault passing from the SE direction of Nainital City. This work finds that different types of discontinuities (e.g. joints and faults), overburden due to unplanned civil structures, and neotectonic activity in the vicinity of this area affect the stability of the city. The slate forms the base of the city, dipping slightly towards the lake side along the NW direction, thus accelerating the instability of this area. Rock mass rating (RMR), slope mass rating, factor of safety (FOS) and graphical analysis of the discontinuity for slope kinematics indicate that the study area is a landslide-prone zone. This study can facilitate reducing the risk of human life, and contribute to the ongoing construction works in the area. 相似文献
6.
Haseeb MD. Irfanullah 《The International journal of environmental studies》2013,70(4):654-667
Armed conflict affects the biological diversity and biological research regime of a country. This paper takes a low-intensity armed conflict in the biologically and ethnically diverse Chittagong Hill Tracts (CHT) of Bangladesh, as an example, and assesses the response of biologists to this conflict. The study spans the last 50 years dividing it into three periods: pre-conflict (1961?1974), conflict (1975–1997) and post-conflict (1998–2011). Interactions with selected researchers and a literature survey showed that sporadic, intermittent biological research was conducted in this region even during the conflict. The number of research initiatives substantially increased and became more diverse over the last decade. Research opportunity has increased mainly because of improved security and accessibility. Nevertheless, despite the research capacity and a positive attitude among the researchers, some fundamental issues still limit long-term research in this area. The continuing volatile situation due to slow implementation of the 1997 Peace Accord and the tension between rebel factions and indigenous and settler communities in some areas continue to be serious concerns for studying and conserving the biodiversity of this region. Innovative research approaches and the full implementation of the peace agreement are vital to improving the situation for biological research in the CHT. The paper underlines the importance of a biologist’s self-motivation to respond to low-intensity armed conflicts. 相似文献
7.
Cloud computing enables a conventional relational database system's hardware to be adjusted dynamically according to query workload, performance and deadline constraints. One can rent a large amount of resources for a short duration in order to run complex queries efficiently on large-scale data with virtual machine clusters. Complex queries usually contain common subexpressions, either in a single query or among multiple queries that are submitted as a batch. The common subexpressions scan the same relations, compute the same tasks (join, sort, etc.), and/or ship the same data among virtual computers. The total time spent for the queries can be reduced by executing these common tasks only once. In this study, we build and use efficient sets of query execution plans to reduce the total execution time. This is an NP-Hard problem therefore, a set of robust heuristic algorithms, Branch-and-Bound, Genetic, Hill Climbing, and Hybrid Genetic-Hill Climbing, are proposed to find (near-) optimal query execution plans and maximize the benefits. The optimization time of each algorithm for identifying the query execution plans and the quality of these plans are analyzed by extensive experiments. 相似文献
8.
9.
Progesterone pharmacokinetics were analyzed for plasma hormone concentrations ranging from linear to saturated metabolism in lactating Holstein cows with differing daily milk yields. The adequacy of 2-coupled first-order (bi-exponential equation), hyperbolic (Michaelis-Menten equation), and sigmoidal (Hill equation) kinetic models to describe the experimental progesterone pharmacokinetic profiles was examined on a statistical basis. After nonlinear regression and statistical analysis of the data-fitting capability, a simple one-compartment model based on Hill equation proved to be most adequate. This model indicates an enzyme-catalyzed metabolism of progesterone involving cooperative substrate-binding sites, resulting from allosteric effects that yield a sigmoidal saturation rate curve. Kinetic parameters were estimated for 2 groups of lactating Holstein cows with different daily milk yields. We found, for the first time, a remarkable quantitative agreement of the Hill coefficient value with that reported in pharmacokinetic studies involving cytochrome P450, family 3, subfamily A (CYP3A)-mediated reactions in other mammals, humans included. It seems that positive cooperativity makes enzymes much more sensitive to plasma progesterone concentration, and their activities can undergo significant changes in a narrow range of concentration as characteristic of sigmoidal behavior. Therefore, the values of classical pharmacokinetic parameters, such as the elimination constant, half-life, and clearance rate, were found to be highly dependent on the plasma progesterone concentration. 相似文献
10.
应用工程反分析求取垮山过程的岩体力学参数时,由于静不定现象得不到唯一解。本文提出的数理统计学的优化法圆满地解决了这一难题,并成功地应用于石人嶂钨矿莲花山垮山预报,避免了一次重大灾害事故。 相似文献