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不同气氛对激光熔覆IN718涂层形貌、组织与性能的影响   总被引:2,自引:2,他引:0  
目的研究不同气氛条件下激光熔覆IN718高温合金涂层的微观偏析。方法利用激光熔覆技术,在不同送粉气和不同保护气条件下制备了IN718高温合金涂层,并对制备的涂层进行双时效热处理。采用光学显微镜观察显微组织结构和特征,采用扫描电镜和能谱仪对涂层组织和相成分进行分析,采用维氏硬度计对涂层热处理前后的硬度进行测定。结果送粉气种类对熔覆层的形貌和组织有一定影响,而保护气种类对熔覆层的形貌和组织影响不明显。与氩气作为送粉气制备的涂层相比,氦气作为送粉气制备的涂层组织更加细密,Laves相的尺寸更小且分布更均匀,Laves相的体积分数由氩气送粉的9.35%减少到氦气送粉的5.25%,并且Laves相中Nb的质量分数由20%下降到16%,涂层硬度由287HV0.2提高到306HV0.2。双时效热处理后,涂层的显微硬度明显提高,氦气作为送粉气制备的涂层硬度为468HV0.2,高于氩气作为送粉气制备的涂层硬度447HV0.2。结论氦气作为送粉气能有效降低激光熔覆IN718涂层的Nb元素偏析,同时细化涂层组织,提高涂层显微硬度。氦气作为保护气对涂层形貌和组织的影响不明显。  相似文献   
3.
International Journal of Coal Science & Technology - The study reviews the process of oxidative desulphurization of high-sulphur Ukrainian lignite, which was performed by coal treatment using...  相似文献   
4.
Neural Computing and Applications - This article introduces a method for realizing the Gaussian activation function of radial-basis (RBF) neural networks with their hardware implementation on...  相似文献   
5.
The paper provides an assessment of the current wind energy potential in Ukraine, and discusses developmental prospects for wind-hydrogen power generation in the country. Hydrogen utilization is a highly promising option for Ukraine's energy system, environment, and business. In Ukraine, an optimal way towards clean zero-carbon energy production is through the development of the wind-hydrogen sector. In order to make it possible, the energy potential of industrial hydrogen production and use has to be studied thoroughly.Ukraine possesses huge resources for wind energy supply. At the beginning of 2020, the total installed capacity of Ukrainian wind farms was 1.17 GW. Wind power generation in Ukraine has significant advantages in comparison to the use of traditional sources such as thermal and nuclear energy.In this work, an assessment of the wind resource potential in Ukraine is made via the geographical approach suggested by the authors, and according to the «Methodical guidelines for the assessment of average annual power generation by a wind turbine based on the long-term wind speed observation data». The paper analyses the long-term dynamics of average annual wind speed at 40 Ukrainian weather stations that provide valid data. The parameter for the vertical wind profile model is calculated based on the data reanalysis for 10 m and 50 m altitudes. The capacity factor (CF) for modern wind turbine generators is determined. The CF spatial distribution for an average 3 MW wind turbine and the power generation potential for the wind power plants across the territory of Ukraine are mapped.Based on the wind energy potential assessment, the equivalent possible production of water electrolysis-derived green hydrogen is estimated. The potential average annual production of green hydrogen across the territory of Ukraine is mapped.It is concluded that Ukraine can potentially establish wind power plants with a total capacity of 688 GW on its territory. The average annual electricity production of this system is supposed to reach up to 2174 bln kWh. Thus, it can provide an average annual production of 483 billion Nm3 (43 million tons) of green hydrogen by electrolysis. The social efficiency of investments in wind-hydrogen electricity is presented.  相似文献   
6.
Using the psychometric paradigm of risk in conjunction with surveys of the Michigan public (n = 638) and a regional planning organization (n = 65), we examine the perceived risk and concerns associated with underwater oil pipelines, the Enbridge Line 5 pipeline in particular, and oil spills under ice. The fate of Line 5 is heavily debated in Michigan, specifically the portion that traverses the Straits of Mackinac, which can be ice-covered for months. Scant literature examines how individuals perceive the risk associated with Line 5, its alternatives, or potential spills in open water or under ice. Here we identify considerable concern regarding both the pipeline and the potential for spills under ice on behalf of the public, and increased concern about spills under ice on behalf of the planning organization. Organization members' concerns are significantly predicted by beliefs about the difficulty in remediating spills, however not by beliefs about spills' likelihood, difficulty in detection, noticeability, or consequences. Our results identify the need to better examine and communicate the risks associated with underwater pipelines and spills, both in open water and under ice, as well as options for remediating oil captured under ice. Furthermore, we recommend the adoption of decision-making and risk governance processes that explicitly expand analysis of the social, economic and environmental tradeoffs of underwater pipelines such as Line 5.  相似文献   
7.
ABSTRACT

The traditional technology of linseed harvesting involves the cutting of the stems with subsequent threshing. During cutting part of the stem remains on the field, which causes significant losses of fibrous raw materials. Threshing of stems by traditional technology also causes significant damage to the linseed straw. Developed resource-saving technology of linseed harvesting provides first linseed thrashing on the plants with subsequent pulling of stems. With this sequence of technological operations, all linseed stems and seeds are preserved without damage. For the implementation of resource-saving technology proposed design of flax thresher and flax puller. The results of experimental studies of the properties of linseed fibre obtained from the linseed showed that such fibre is suitable for the production of non-woven materials, technical textiles and paper. The introduction of resource-saving technology of linseed harvesting will save the harvest of seeds and straw with minimal losses and damage. Resource-saving technology will increase the profitability of linseed cultivation.  相似文献   
8.
Ischemic and hemorrhagic strokes are associated with severe functional disability and high mortality. Except for recombinant tissue plasminogen activator, therapies targeting the underlying pathophysiology of central nervous system (CNS) ischemia and hemorrhage are strikingly lacking. Sur1-regulated channels play essential roles in necrotic cell death and cerebral edema following ischemic insults, and in neuroinflammation after hemorrhagic injuries. Inhibiting endothelial, neuronal, astrocytic and oligodendroglial sulfonylurea receptor 1–transient receptor potential melastatin 4 (Sur1–Trpm4) channels and, in some cases, microglial KATP (Sur1–Kir6.2) channels, with glibenclamide is protective in a variety of contexts. Robust preclinical studies have shown that glibenclamide and other sulfonylurea agents reduce infarct volumes, edema and hemorrhagic conversion, and improve outcomes in rodent models of ischemic stroke. Retrospective studies suggest that diabetic patients on sulfonylurea drugs at stroke presentation fare better if they continue on drug. Additional laboratory investigations have implicated Sur1 in the pathophysiology of hemorrhagic CNS insults. In clinically relevant models of subarachnoid hemorrhage, glibenclamide reduces adverse neuroinflammatory and behavioral outcomes. Here, we provide an overview of the preclinical studies of glibenclamide therapy for CNS ischemia and hemorrhage, discuss the available data from clinical investigations, and conclude with promising preclinical results that suggest glibenclamide may be an effective therapeutic option for ischemic and hemorrhagic stroke.  相似文献   
9.
The main goal of the work is to increase the accuracy of the anthropomorphic manipulator master-slave teleoperation by calculating the coordinates of the operator’s arm joints. The master device is an exoskeleton worn on the operator’s arm, and the slave device is an anthropomorphic manipulator. A method based on the solution of the forward kinematics and empirical simplifications is proposed in this paper. The position of the nodal points of the exoskeleton was calculated by solving the direct kinematics problem. The coordinates of the operator’s arm joints, which were rigidly connected to the exoskeleton nodal points, were calculated geometrically. For the operator’s arm elbow joint, which was flexibly connected to the exoskeleton, an empirical relation was proposed. It simplified the calculation of the elbow joint position. The experiment showed a decrease in the mismatch between the operator’s arm angles and the manipulator joint angles from 20.7° to 2.9°. The proposed method increases the convenience of the master-slave control.  相似文献   
10.
The possibility of increasing the sensitivity of a neutron detector based on a TlInSe2 crystal by introducing the 6Li isotope into this crystal is investigated. Introduction of the isotope is conducted by the method of electrochemical intercalation from aqueous and nonaqueous solutions of LiCl and also from the melt of the LiCl–KCl eutectic. It is shown that intercalation by the electrochemical method from a LiCl solution in propylene carbonate, performed along the “c” axis of the crystal (along strong bond chains) is efficient. The attained concentration of introduced lithium amounts to (1–1.2) × 1021 cm–3, which increased the sensitivity of the detector by approximately four times. Good agreement between the calculated and experimental values of the detector sensitivity is demonstrated.  相似文献   
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