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61.
ABSTRACT Solvent sorption and drying performance of engineering polymeric blends of ethylene–propylene random copolymer and isotactic polypropylene in the presence of aromatic liquid: has been studied in the temperature interval 25–70°C. The drying of the polymer is studied from the desorption and redesorption experiments. The present results indicate that the rate of solvent migration and the drying phenomenon is controlled by internal mass transfer of solvent molecules within the polymer matrix. A technique is developed to study the sorption (S) –desorption (D) – resorption (RS)–redesorption (RD) i.e., S–D–RS–RD of the polymer sheets. The S–D–RS–RD experiments are a convenient measure of knowing the continuous weight loss of the polymer during long–term solvent exposure. 相似文献
62.
Wireless Personal Communications - Since the last decade, cloud-based Electronic Health Records (EHRs) have achieved important consideration to facilitate remote access of patient medical records.... 相似文献
63.
Prosanta Gope Hemant Ghayvat Yongqiang Cheng Sohag Kabir 《International Journal of Communication Systems》2023,36(12):e4199
Rapid development of wireless networks brings about many security problems in portable communication systems (PCSs), which can provide mobile users with an opportunity to enjoy global roaming services. In this regard, designing a secure user authentication scheme, especially for recognizing legal roaming users, is indeed a challenging task. It is noticed that there is no delegation-based protocol for PCSs, which can guarantee anonymity, untraceability, perfect forward secrecy, and resistance of denial-of-service (DoS) attack. Therefore, in this article, we put forward a novel delegation-based anonymous and untraceable authentication protocol, which can guarantee to resolve all the abovementioned security issues and hence offer a solution for secure communications for PCSs. 相似文献
64.
65.
Singh Chitranjan Prasad Agrawal Hemant Mishra Arvind Kumar 《Bulletin of Engineering Geology and the Environment》2021,80(10):8009-8019
Bulletin of Engineering Geology and the Environment - Vibrations induced due to blasting in mines may damage the nearby houses and disturb the habitants. The monitoring, prediction, and control of... 相似文献
66.
Han Gang Zhou Hui Hou Jing Zhang Chuanqing Singh Hemant Kumar Gao Yang 《Bulletin of Engineering Geology and the Environment》2021,80(11):8765-8787
Bulletin of Engineering Geology and the Environment - Interlayer shear weakness zone (ISWZ) is a type of weak deformation zone in stratified rock masses with variable thicknesses and undulations,... 相似文献
67.
Emad L. LABIB Hemant B. DHONDE Thomas T. C. HSU Y. L. MO 《Frontiers of Structural and Civil Engineering》2014,8(4):373
Normal strength prestressed concrete I-girders are commonly used as the primary superstructure components in highway bridges. However, shear design guidelines for high strength PC girders are not available in the current structural codes. Recently, ten 7.62 m (25 feet) long girders made with high strength concrete were designed, cast, and tested at the University of Houston (UH) to study the ultimate shear strength and the shear concrete contribution (Vc) as a function of concrete strength ( ). A simple semi-empirical set of equations was developed based on the test results to predict the ultimate shear strength of prestressed concrete I-girders. The UH-developed set of equations is a function of concrete strength ( ), web area (bwd), shear span to effective depth ratio (a/d), and percentage of transverse steel (ρt). The proposed UH-Method was found to accurately predict the ultimate shear strength of PC girders with concrete strength up to 117 MPa (17000 psi) ensuring satisfactory ductility. The UH-Method was found to be not as overly conservative as the ACI-318 (2011) code provisions, and also not to overestimate the ultimate shear strength of high strength PC girders as the AASHTO LRFD (2010) code provisions. Moreover, the proposed UH-Method was found fairly accurate and not exceedingly conservative in predicting the concrete contribution to shear for concrete strength up to 117 MPa (17000 psi). 相似文献
68.
Hemant Sharma Richard M. HuizengaAleksei Bytchkov Jilt SietsmaS. Erik Offerman 《Acta Materialia》2012,60(1):229-237
Understanding the underlying mechanisms of grain coarsening is important in controlling the properties of metals, which strongly depend on the microstructure that forms during the production process or during use at high temperature. Grain coarsening of austenite at 1273 K in a binary Fe-2 wt.% Mn alloy was studied using synchrotron radiation. Evolution of the volume, average crystallographic orientation and mosaicity of more than 2000 individual austenite grains was tracked during annealing. It was found that an approximately linear relationship exists between grain size and mosaicity, which means that orientation gradients are present in the grains. The orientation gradients remain constant during coarsening and consequently the character of grain boundaries changes during coarsening, affecting the coarsening rate. Furthermore, changes in the average orientation of grains during coarsening were observed. The changes could be understood by taking the observed orientation gradients and anisotropic movement of grain boundaries into account. Five basic modes of grain coarsening were deduced from the measurements, which include: anisotropic (I) and isotropic (II) growth (or shrinkage); movement of grain boundaries resulting in no change in volume but a change in shape (III); movement of grain boundaries resulting in no change in volume and mosaicity, but a change in crystallographic orientation (IV); no movement of grain boundaries (V). 相似文献
69.
Hemant SinghK.L. Yadav 《Materials Chemistry and Physics》2012,132(1):17-21
Polycrystalline BiFe1−xNbxO3 ceramics have been synthesized by standard solid-state reaction method. The effect of Nb substitution on the dielectric, magnetic and magnetoelectric properties of the BiFeO3 multiferroic perovskite was studied. X-ray diffraction pattern revealed that all the samples with x = 0.00-0.10 showed rhombohedral perovskite structure. We obtained single phase upto doping concentration of x = 0.05 and with further increase in Nb concentration, some impurity peaks appeared. An anomaly in the dielectric constant (?) and dielectric loss (tan (δ)) in the vicinity of the antiferromagnetic Néel temperature (TN) was observed. Nb substitution reduced the antiferromagnetic Néel temperature (TN) in BiFe1−xNbxO3. Proper amount of Nb could decrease the dielectric loss. Magnetic hysteresis loops measured at 5 K/300 K and temperature dependent magnetization curves indicated ferromagnetism in Nb substituted BiFeO3 ceramics. The room temperature magnetic moment was found to increase with increase in Nb concentration. The dependence of dielectric constant on the magnetic field is an evidence of magnetoelectric coupling in BiFe1−xNbxO3 ceramics. 相似文献
70.
N. L. Panwar Hemant Y Shrirame B. R. Bamniya 《Clean Technologies and Environmental Policy》2010,12(5):579-582
Biodiesel has become an interesting alternative to be used in diesel engine, because it has similar properties to the traditional
fossil diesel fuel and may, thus, substitute conventional fuel with none or very minor engine modification. This article deals
with alkaline transesterfication of castor oil and their properties for engine application. The purpose of the transesterfication
process is to lower the viscosity of the oil from 226.82 cS to 8.50 cS ‘at’ 38°C. The flash point values of castor methyl
esters are lower than that of castor oil. The density and gross calorific value of castor methyl ester are much closer to
those of diesel. If 10% of total production of castor seed oil is transesterfied into biodiesel, then about 79,782 tones of
CO2 emission can be saved on annual basis. The CO2 released during combustion of biodiesel can be recycled through next crop production, therefore, no additional burden on
environment. 相似文献