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41.
Nanotechnology is currently being widely employed in agriculture and horticulture. The most widely investigated and developed factor related to fruit trees is nanofertilizers (NFs), which play very important roles in increasing vegetative growth, improving reproductive growth and flowering, thereby increasing productivity, product quality and ultimately increasing shelf-life and decreasing fruit waste. These nanomaterials, which are generally sprayed at low concentrations on trees at different time intervals and in frequent sessions, are also considered as growth stimulants. Macro- and micro-scale NFs such as zinc, boron, chitosan, and fertilizer nanocomposites such as ZnFeMnB (zinc, iron, manganese, boron), NPKMg (nitrogen, phosphorus, potassium, magnesium), and calcite have been shown to significantly improve the vegetative and reproductive traits of fruit trees such as pomegranate, strawberry, mango, date, coffee and grape. Knowledge on the effects of NFs on fruit trees and biological reasons for their effects on different traits is incomplete and there is an urgent need for extensive research on these topics. © 2019 Society of Chemical Industry  相似文献   
42.
Knowing of thermoset curing kinetics is essential for process development, quality control, and achieving desirable products. Hence, in this article, cure kinetics of an EPON 828 epoxy resin/dicyandiamide curing agent/diuron accelerator system is investigated. This resin system is usually used for the production of epoxy/glass fiber prepregs used in wind turbine blades. For this, differential scanning calorimetry analysis is used and the effect of temperature, weight percentage, and size of nanosilica is studied by conducting isothermal tests at several temperatures for samples with and without nanoparticles. An autocatalytic curing model is applied to describe the cure kinetic of system and then the variations in model parameters calculated by curve fitting using the MATLAB software. The results show that the increase in temperature, weight percentage of nanosilica from 0 to 6%, and surface area of nanosilica particles lead to the increase in curing rate, whereas the increase in the percentage and surface area of nanosilica particles significantly decreases total heat of reaction. At the end, the relation between each of model parameters and the total surface area of nanosilica particles, calculated by mathematical equations, is obtained. The allowable maximum surface area of nanosilica used in the mathematical equations is 12 m2 g−1. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47958.  相似文献   
43.
In the current research, the effects of TiO2 additive on mechanical and physical properties of SiC bodies, sintered by liquid phase methods were investigated. Al2O3 and Y2O3 were used as sintering-aids (10?wt% in total) with an Al2O3/Y2O3 ratio of 43/57 to provide liquid phase during Sintering. TiO2 was also used as the oxide additive with an amount ranging from 0 to 10?wt%. After scaling and mixing the starting materials by a planetary mill, the obtained slurry was dried at 100?℃ for four hours. The derived powders were finally pressed under a pressure of 90?MPa. The samples were then pyrolyzed and sintered at 600?℃ and 1900?℃, respectively under argon atmosphere for 1.5?h. Phase analysis showed no trace of TiO2 after the sintering process, demonstrating the complete TiO2 to TiC transformation. The results showed that an increase in TiO2 content up to 5?wt%, led an improvement in all the measured properties including the relative density, hardness, Young's modulus, bending strength, indentation fracture resistance and the brittleness factor, reaching to 96.2%, 24.4?GPa, 395.8?GPa, 521?MPa, 5.8?MPa?m1/2 and 286.5?×?10?6 m?1, respectively. However more than 5?wt% additive resulted in a decrease in all the above-mentioned properties. Microstructural studies demonstrated that crack deflection and crack bridging were the major mechanisms responsible for an increase in the indentation fracture resistance.  相似文献   
44.
Depression is a common psychiatric disorder in patients with advanced chronic kidney diseases (CKDs). Strong correlation has been reported between depression and patients' morbidity and mortality among dialysis patients. On the contrary, chronic inflammation may be a major contributor to morbidity and mortality in these patients. Elevated plasma levels of proinflammatory cytokines, especially C‐reactive protein and interleukin (IL)‐6, have been correlated with cardiovascular events, hospitalization, and all‐cause and cardiovascular‐associated mortality in dialysis patients. Studies suggested that inflammation‐mediated atherosclerotic cardiovascular diseases are the possible reasons for depression‐induced mortality among patients without renal diseases. Several studies found significant elevations in circulating levels of proinflammatory cytokines, particularly IL‐6 and tumor necrosis factor‐α, in patients with major depression. Furthermore, depressive mood and behaviors, including sadness and suicidal ideation, were observed in patients who received repeated injections of recombinant cytokines. A thorough literature review indicates that while depressive symptoms and elevated inflammatory cytokine levels coexist in CKD and dialysis patients, their association is uncertain. Depression seems to be more associated with elevated serum levels of IL‐6 than other cytokines in these patients. Further studies are needed to clarify the possibility of a causal relationship between inflammation and depressive symptoms in CKD and dialysis patients.  相似文献   
45.
The major goal of the evaluation and management of DLP in children is to provide safe and effective therapy with lifestyle modification. There is a strong rationale for the initiation of DLP treatment in childhood to limit the earliest stages of atherosclerosis, to establish lifelong lifestyle changes in diet and activity, and to limit the acquisition of additional CVD risk factors such as smoking and obesity. The NCEP has recommended screening for children with a parent with total cholesterol of 240 mg/dL or greater or a parent or grandparent with onset of CVD before age 55 years. Clinical evaluation and management are based on an LDL-C level of 130 mg/dL or greater. This approach to screening has a low sensitivity to identify children with DLP. Initial therapy is with a step 1 diet followed by the step 2 diet if necessary. Medications are reserved for older children with LDL-C of 190 mg/dL or greater after diet therapy or 160 mg/dL or greater with other CVD risk factors.  相似文献   
46.
Spelling correction is a fundamental task in text mining. In this study, we assess the real-word error correction model proposed by Mays, Damerau and Mercer and describe several drawbacks of the model. We propose a new variation which focuses on detecting and correcting multiple real-word errors in a sentence, by manipulating a probabilistic context-free grammar to discriminate between items in the search space. We test our approach on the Wall Street Journal corpus and show that it outperforms Hirst and Budanitsky’s WordNet-based method and Wilcox-O’Hearn, Hirst, and Budanitsky’s fixed windows size method.  相似文献   
47.
The effective application of liquefaction mitigation techniques requires an improved understanding of the development and consequences of liquefaction. Centrifuge experiments were performed to study the dominant mechanisms of seismically induced settlement of buildings with rigid mat foundations on thin deposits of liquefiable sand. The relative importance of key settlement mechanisms was evaluated by using mitigation techniques to minimize some of their respective contributions. The relative importance of settlement mechanisms was shown to depend on the characteristics of the earthquake motion, liquefiable soil, and building. The initiation, rate, and amount of liquefaction-induced building settlement depended greatly on the rate of ground shaking. Engineering design procedures should incorporate this important feature of earthquake shaking, which may be represented by the time rate of Arias intensity (i.e., the shaking intensity rate). In these experiments, installation of an independent, in-ground, perimetrical, stiff structural wall minimized deviatoric soil deformations under the building and reduced total building settlements by approximately 50%. Use of a flexible impermeable barrier that inhibited horizontal water flow without preventing shear deformation also reduced permanent building settlements but less significantly.  相似文献   
48.
The scalability feature of cloud computing attracts application service providers (ASPs) to use cloud application hosting. In cloud environments, resources can be dynamically provisioned on demand for ASPs. Autonomic resource provisioning for the purpose of preventing resources over-provisioning or under-provisioning is a widely investigated topic in cloud environments. There has been proposed a lot of resource-aware and/or service-level agreement (SLA)-aware solutions to handle this problem. However, intelligence solutions such as exploring the hidden knowledge on the Web users’ behavior are more effective in cost efficiency. Most importantly, with considering cloud service diversity, solutions should be flexible and customizable to fulfill ASPs’ requirements. Therefore, lack of a flexible resource provisioning mechanism is strongly felt. In this paper, we proposed an autonomic resource provisioning mechanism with resource-aware, SLA-aware, and user behavior-aware features, which is called three-dimensional mechanism. The proposed mechanism used radial basis function neural network in order to provide providence and flexibility features. The experimental results showed that the proposed mechanism reduces the cost while guarantees the quality of service.  相似文献   
49.
In this paper,a new simple structure of indexguiding photonic crystal fiber (PCF) is designed and presented.In this PCF,dispersion,confinement loss,and effective mode area characteristics are investiga...  相似文献   
50.
Ad Hoc network is a temporal network which is managed by autonomous nodes which have the ability to communicate with each other without having fixed network infrastructure or any central base station. Due to some reasons such as dynamic changes of the network topology, trusting the nodes to each other, lack of fixed substructure for the analysis of nodes’ behaviours and loss of specific offensive lines, this type of networks is not supportive against malicious nodes’ attacks. One of these attacks is black hole attack. In this attack, the malicious nodes absorb data packets and destroy them. Thus, it is essential to present an algorithm against the black hole attacks. This article suggests a new algorithm which enhances the security of AODV routing protocol to encounter the black hole attacks. This algorithm tries to identify malicious nodes according to nodes’ behaviours in an Ad Hoc network and delete them from routing. The suggested algorithm is simulated by NS2. The simulation results show some improvements in end-to-end delay and packet delivery rate in the suggested algorithm.  相似文献   
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