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101.
Power plants are one of the major industries suffering from severe erosion–corrosion (E‐C) problems resulting in substantial losses. One way of tackling this problem is by the use of thermal spray coatings. In the current investigation a new emerging technique i.e. cold spray coating process was used to deposit Ni‐20Cr and Ni‐50Cr powder on SA 516 (grade 70) boiler steel. The bare as well as the coated steels were subjected to cyclic experimental studies, in the superheater zone of a coal fired boiler. Weight change, thickness loss, XRD, FE‐SEM/EDS and X‐ray mapping techniques were used to analyse the eroded‐corroded specimens. The uncoated steel showed weight gain after exposure in the actual boiler environment, whereas, for the coated steels there was initial weight loss followed by negligible weight change. Based upon thickness loss data the cold‐sprayed Ni‐50Cr coating was found to provide better E‐C resistance than the Ni‐20Cr coating. 相似文献
102.
Prakash Bhartia Oliver O'Reilly 《The International journal of environmental studies》2013,70(3):173-175
This paper presents the results of a survey on the radiation leakage from a representative sample of microwave ovens in Regina. A brief review of potential hazards of microwave radiation is presented and the results of the survey are analyzed with a view of initiating further research in this area. 相似文献
103.
104.
Satya Prakash Kar 《传热工程》2013,34(16):1427-1438
A one-dimensional transient coupled conduction-radiation numerical model is developed to investigate the laser melting of semitransparent material under a continuous collimated laser pulse in a convective cooling environment. The medium is considered absorbing, emitting, and scattering. The thermophysical properties are taken to be different for different phase fields. Volumetric radiation is incorporated in the proposed model. The radiation information is obtained by solving the equation of transfer. The temperature field is obtained by solving the energy equation with internal radiation source. The finite-volume method is used to discretize both the equation of transfer and the energy equation. The enthalpy formulation is adopted to capture the continuously evolving solid–liquid interface during the phase change. The laser source is approximated with the collimated radiation source. Collimated intensity is captured directly (without splitting the total intensity into two parts: diffuse and collimated) by adjusting the control angles. The present model is first validated with the existing phase-change model in the literature. Then the effects of different parameters such as optical thickness, scattering albedo, and the conduction–radiation parameter on the liquid fractions and temperature distribution in the medium are studied. It is observed that when the radiation is dominant, the temperature in the medium is high and hence the liquid fraction is more, in contrast to conduction-dominated phase change. 相似文献
105.
Fracture toughness is the ability of a component containing a flow to resist fracture. In the current study, the Ball indentation (BI) test technique, which is well acknowledged as an alternative approach to evaluate mechanical properties of materials due to its semi-nondestructive, fast, and high accurate qualities is used to estimate damage and the fracture toughness for copper samples subjected to varying levels of creep and fatigue. The indentation fracture toughness shows the degradation of Cu samples when they are subjected to different creep conditions. Axial fatigue cycling increases the strength at the mid-gauge section compared to other regions of the samples due to initial strain hardening. The advancement of indentation depth with indentation fatigue cycles experiences transient stage, i.e., jump in indentation depth has been observed, which may be an indication of failure and followed by a steady state with almost constant depth propagation with indentation cycles. 相似文献
106.
A geometrically nonlinear, simply supported beam under the influence of time-dependent external forcing serves as a testbed to demonstrate application of the optimal spatiotemporal reduced order modeling (OPSTROM) framework proposed in Part I of this work. Fully resolved simulations, which are relatively expensive to perform, are used to accurately predict the beam response for a few forcing parameters. More affordable simulations are achieved with a conventional finite-difference scheme by coarsening the computational grid in space and time. Discretization errors are reduced with OPSTROM as subgrid-scale models are designed to account for the underlying space-time statistical structure using principles of mean-square error minimization, conditional expectations and stochastic estimation. When included in the under-resolved simulations, these optimal subgrid-scale models are shown to significantly improve the accuracy of predictions for both periodic and chaotic response types. This improved accuracy is further demonstrated through a set of numerical experiments designed to capture the complex bifurcation behavior of the beam response. 相似文献
107.
108.
Nepal, one of the least developed countries, is characterized by low per capita energy consumption and hugely dominated by traditional energy sources. Despite having enormous potential of hydro-electricity, only 50% of the total population has access to grid electricity. Firewood is the primary energy source for domestic purposes in rural environments. Due to geographical remoteness, a scattered consumer, higher costs of supply and maintenance, low consumption and low level of households’ income linking the rural areas to national electricity grid is difficult and implausible. In order to solve the energy problem in rural areas, Nepal’s government has initiated the production and distribution of several renewable energy technologies. Among several renewable technologies, micro-hydropower has been one of the most promising and widely adopted decentralized technologies to distribute electricity in rural areas. This article begins with a general overview of energy situation in Nepal. Present status and perspective of micro-hydro plants have also been discussed. Similarly, the dynamics of the relationship between electricity and socio-economic development has been analyzed by means of a typical rural electrification project in Tangting, Nepal by assessing the impacts of electricity on health, education, environment, and income in the village. The community has greatly benefitted from the arrival of environment friendly and affordable electricity. It has been concluded that the task of providing electricity to more remote and isolated villages is still challenging in Nepal. More systematic and comprehensive study supported by research and development is required to extend micro-hydro based electricity in more remote and poor communities of Nepal. 相似文献
109.
Sreeraj Gopi Augustine Amalraj Karthik Varma Shintu Jude Prakash B. Reddy Chandradhara Divya 《国际聚合物材料杂志》2018,67(9):581-588
A phytogenic feed additive (PFA) formulation was prepared with bioactive molecules—curcuminoids, gingerol, and carvacrol by encapsulating in nanofiber isolated from turmeric spent (turmeric nanofiber, TNF). This formulation was completely characterized by scanning electron microscope, ultra performance liquid chromatography, and gas chromatography and evaluated for its efficacy. PFA-encapsulated TNF (PFA@TNF) considerably increased mean body weight, decreased cholesterol level, mortality rate, and reduced Escherichia coli content of broilers than antibiotic growth promoter (AGP). The depth of crypts in the ileum of broilers was considerably reduced by the inclusion of PFA@TNF in diets compared with the AGP. 相似文献
110.
A. S. Prakash A. M. A. Khadar K. C. Patil M. S. Hegde 《Journal of Materials Synthesis and Processing》2002,10(3):135-141
Hexamethylenetetramine, (CH2)6N4 (HMT) has been employed as a fuel for the first time to synthesize several binary, ternary, and quaternary oxides by the solution combustion method. Technologically important oxides, namely, zirconia, ceria, and their solid solutions, -Al2O3, Cr3+-doped -Al2O3, spinels, MAl2O4 (M = Ca, Mg, Zn and Ni), perovskites, LaMO3 (M = Mn, Cr and Al), La0.67Sr0.33MnO3, and La0.67Ca0.33MnO3, have been synthesized. The oxides synthesized are characterized by X-ray powder diffraction, resistivity, fluorescence spectra, particle size, and surface area measurements. Decomposition of nickel nitrate-HMT complex has been investigated by TG, DTA, TPD, and evolved-gas analysis to elucidate the mechanism. 相似文献