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41.
K. Ganesan S. Ilango Mariyappan Shanmugam M. Farrokh Baroughi M. Kamruddin A.K. Tyagi 《Current Applied Physics》2013,13(9):1865-1869
The loss of local dielectric integrity in ultrathin Al2O3 films grown by atomic layer deposition is investigated using conducting atomic force microscopy. I–V spectra acquired at different regions of the samples by constant and ramping voltage stress are analyzed for their pre- and post-breakdown signatures. Based on these observations, the thickness dependent dielectric reliability and failure mechanism are discussed. Our results show that remarkable enhancement in breakdown electric field as high as 130 MV/cm is observed for ultrathin films of thickness less than 1 nm. 相似文献
42.
Wavelet-modified fringe-adjusted joint transform correlator 总被引:1,自引:1,他引:0
Alpana Bhagatji Naveen K. Nishchal Arun K. Gupta B.P. Tyagi 《Optics & Laser Technology》2008,40(1):99-112
In this paper, we implement a wavelet-modified fringe-adjusted joint transform correlator (JTC) for real-time target recognition applications. In real-time situation the input scene is captured using a charge-coupled device (CCD) camera. The obtained joint power spectrum is multiplied by a pre-synthesized fringe-adjusted filter and the resultant function is processed with an appropriately scaled wavelet filter. Three performance measure parameters: correlation peak intensity, peak-to-sidelobe ratio, and signal-to-clutter ratio have been calculated for fringe-adjusted joint transform correlator (FJTC) and wavelet-modified fringe-adjusted joint transform correlator (WFJTC). The WFJTC has been found to yield better results in comparison to conventional FJTC. To suppress the undesired strong dc, the resultant function is differentiated. Differential processing wavelet-modified fringe-adjusted joint power spectrum removes the zero-order spectra and hence improves the detection efficiency. To focus the correlation terms in different planes in order to capture one of the desired autocorrelation peaks and discard the strong dc and another autocorrelation peak, chirp-encoding technique has also been applied. Targets with Gaussian and speckle noise have also been used to check the correlation outputs. Computer simulation and experimental results are presented. 相似文献
43.
Mohit Tyagi 《Journal of luminescence》2008,128(1):22-26
UV excited luminescence of lead molybdate (PbMoO4, PMO) single crystals grown under controlled conditions has been studied at room temperature in both spectral and temporal domains. In literature, the luminescence from PMO crystals has been investigated by exciting with UV or synchrotron radiation sources. The results presented here show that the emission spectrum is a sensitive function of the crystal composition and both green and blue emissions may be observed at room temperature in crystals possessing minor stoichiometric deviations. 相似文献
44.
Here we report the results of combined powder X-ray and neutron diffraction studies of Bi4?x Nd x Ti3O12 (0.0 ≤ x ≤ 2.0) compositions. The parent Bi4Ti3O12 has an orthorhombic lattice (space group: B2cb) with unit cell parameters a = 5.4432(5) Å, b = 5.4099(5) Å and c = 32.821(2) Å, and V = 966.5(1) Å3. This orthorhombic lattice is retained in all the studied compositions. The unit cell parameters gradually decrease with Nd3+ ion concentration with a discontinuity at x = 0.75. Orthorhombicity of the lattice decreases with increase in Nd3+ content in the lattice. The orthorhombic unit cell parameters for a representative Bi2Nd2Ti3O12 composition are: a = 5.3834(9), b = 5.3846(9) and c = 32.784(1) Å. The observed orthorhombic distortion at x = 2.0 is very small and thus the crystal structure apparently has a pseudo-tetragonal lattice. In addition, Nd3+ preferentially substitutes in the perovskite slab of the Aurivillius structure. The fraction of Nd3+ in the fluorite slab increases with increase in Nd3+ contents. 相似文献
45.
Shadap Lathewdeipor Tyagi Jaya Lakshmi Poluri Krishna Mohan Novikov Sergei Lo Chun-Wan Timothy Mozharivskyj Yurij Kollipara Mohan Rao 《Transition Metal Chemistry》2021,46(3):231-240
Transition Metal Chemistry - Metal complexes 1–9 have been synthesized by reacting the benzothiazole–pyrazole derivative ligands (L1, L2 and L3) with the metal precursors of ruthenium... 相似文献
46.
Gurusamy Arumugam Jagmohan Tyagi 《Mathematical Methods in the Applied Sciences》2020,43(10):6576-6597
We establish the existence of nonnegative weak solutions to nonlinear reaction–diffusion system with cross-diffusion and nonstandard growth conditions subject to the homogeneous Neumann boundary conditions. We assume that the diffusion operators satisfy certain monotonicity condition and nonstandard growth conditions and prove that the existence of weak solutions using Galerkin's approximation technique. 相似文献
47.
48.
Francesca Deganello Avesh Kumar Tyagi 《Progress in Crystal Growth and Characterization of Materials》2018,64(2):23-61
Solution combustion synthesis (SCS) is a worldwide used methodology for the preparation of inorganic ceramic and composite materials with controlled properties for a wide number of applications, from catalysis to photocatalysis and electrocatalysis, from heavy metal removal to sensoristics and electronics. The high versatility and efficiency of this technique have led to the introduction of many variants, which allowed important optimization to the prepared materials. Moreover, its ecofriendly nature encouraged further studies about the use of sustainable precursors for the preparation of nanomaterials for energy and environment, according to the concept of circular economy. On the other hand, the large variety of expressions to define SCS and the often-contradictory definitions of the SCS parameters witnessed a scarce consciousness of the potentiality of this methodology. In this review article, the most important findings about SCS and the selection criteria for its main parameters are critically reviewed, in order to give useful guidelines to those scientists who want to use this methodology for preparing materials with improved or new functional properties. This review aims as well (i) to bring more clarity in the SCS terminology (ii) to increase the awareness of the SCS as a convenient tool for the synthesis of materials and (iii) to propose a new perspective in the SCS, with special attention to the use of ecofriendly procedures. Part of the review is also dedicated to precautions and limitations of this powerful methodology. 相似文献
49.
Transport in Porous Media - Compaction and sand migration are important problems in loosely consolidated and unconsolidated high-rate gas reservoirs, and proppants in the hydraulic fractures. Their... 相似文献
50.
Deepika Kushwaha S. N. Upadhyay Pradeep Kumar Mishra 《Applied biochemistry and biotechnology》2018,184(4):1247-1262
Growths of Lyngbya limnetica and Oscillatoria obscura were investigated at varying pH, light intensity, temperature, and trace element concentration with a view to optimize these parameters for obtaining the maximum carbohydrate content. The maximum growth for both strains was obtained at pH 9.0 and temperature 20 ± 3 °C using a light intensity of 68.0 μmol m?2 s?1 with continuous shaking. Growth under the nitrogen starvation condition affected the carbohydrate content more compared to the phosphorus starvation, and maximum concentrations were found as 0.660 and 0.621 g/g of dry biomass for L. limnetica and O. obscura, respectively. Under the optimized nitrogen-rich conditions, the specific growth rates for the two strains were found to be 0.187 and 0.215 day?1, respectively. The two-stage growth studies under nitrogen-rich (stage I) followed by nitrogen starvation (stage II) conditions were performed, and maximum biomass and carbohydrate productivity were found as 0.088 and 0.423 g L?1 day?1 for L. limnetica. This is the first ever attempt to evaluate and optimize various parameters affecting the growth of cyanobacterial biomass of L. limnetica and O. obscura as well as their carbohydrate contents. 相似文献