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111.
Magnetic iron nanoparticles are attracting a great deal of research and application interest in diversified fields. In this present investigation, iron nanoparticles were prepared by a in-situ chemical reduction technique in a combination of polyaniline (PANI)-polyacrylamide (PA) and PANI-hyperbranched polyurethane (HBPU) matrices to judge the suitability of hyperbranched system. The formation of the nanoparticles in polymer matrices has been investigated by FTIR, UV, XRD, SEM and TEM studies. Narrower size with better dispersion and more stable nanoparticles were found in a hyperbranched matrix system compared to a linear one. The particle size was found to be in the range of 10–20 nm and 12–35 nm in HBPU-PANI and PA-PANI matrices, respectively. Both the nanocomposites exhibit synergistic free radical scavenging capability towards 2,2-diphenyl-1-picrylhydrazyl (DPPH). The magnetic hysteresis loop of the nanocomposites indicates the super-paramagnetic behavior. The hyperbranched system is more thermostable than the linear system by 70°C. 相似文献
112.
Bhupen Deka 《Numerical Methods for Partial Differential Equations》2019,35(5):1630-1653
We derive residual‐based a posteriori error estimates of finite element method for linear wave equation with discontinuous coefficients in a two‐dimensional convex polygonal domain. A posteriori error estimates for both the space‐discrete case and for implicit fully discrete scheme are discussed in L∞(L2) norm. The main ingredients used in deriving a posteriori estimates are new Clément type interpolation estimates in conjunction with appropriate adaption of the elliptic reconstruction technique of continuous and discrete solutions. We use only an energy argument to establish a posteriori error estimates with optimal order convergence in the L∞(L2) norm. 相似文献
113.
A. K. Mishra P. Morang M. Deka S. Nishanth Kumar B. S. Dileep Kumar 《Applied biochemistry and biotechnology》2014,174(2):506-521
Induction of systemic resistance in host plants through microbes and their bioactive metabolites are attaining popularity in modern agricultural practices. In this regard, individual application of two strains of Pseudomonas, RRLJ 134 and RRLJ 04, exhibited development of induced systemic resistance in tea plants against brown root rot and charcoal stump rot under split root experiments. The experimental findings also confirmed that the cuttings treated with fungal test pathogen and plant growth-promoting rhizobacteria (PGPR) strains survived longer as compared with pathogen–alone-treated cuttings. The enzyme level studies revealed that the presence of PGPR strains reduced the viscosity loss of cellulose and pectin by both the pathogens to a significant level. The activity of defense-related enzymes like l-phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase were also recorded higher in tea cuttings treated with PGPR strains in presence of pathogen. Crude bioactive metabolites isolated from these strains also showed in vitro antagonism against the test pathogens besides reducing the number of diseased plants under gnotobiotic conditions. These findings confirm the utilization of these two strains for induction of systemic resistance against two major root diseases in tea plants under plantation conditions. 相似文献
114.
Lakhinath Saikia Dhrubajyoti Talukdar Ramesh C. Deka Ashim J. Thakur 《Journal of heterocyclic chemistry》2013,50(5):1031-1038
KI‐VO(acac)2‐H2O2 in aqueous ethanolic medium with acetic acid as additive has been found to iodinate pyrimidinediones and aromatic amines. The methodology is mild, efficient, and environmentally benign. Density functional theory‐based reactivity parameters support the experimentally observed reactivity of pyrimidinedione derivatives. 相似文献
115.
Bimal K. Deka 《International Journal of Infrared and Millimeter Waves》1985,6(12):1285-1294
The thresholds for CO2 laser induced breakdown and their variation with pulse width have been measured at various pressures for Ar, N2 and an 8/1/1 laser mixture of He/CO2/N2 using 3–40 ns duration pulses. These measurements indicate that excited state production plays a dominant role in determining the threshold for nanosecond duration pulses. This has been confirmed by the good agreement obtained between the measured and theoretical thresholds. 相似文献
116.
A study of a pulsed transversely excited HF laser using an unstable resonator configuration is reported. It is shown that parasitic oscillation can be controlled and near diffraction limited performance achieved. A peak radiance of ≈8 × 1012 W cm?2 sr?1 has been obtained with a 4 MW oscillator. 相似文献
117.
The use of a continuously tunable CO2 laser to optically pump the NH3 laser via previously inaccessible absorption lines is described. Efficient laser action has thus been achieved in the 11–13 μm region on transitions formerly only obtained in buffered mixtures. 相似文献
118.
We present alternative proofs of some of Ramanujan’s theta function identities associated with the modular equations of composite
degree 15. Along the way we also find some new theta-function identities. We also give simple proofs of his modular equations
of degree 15. 相似文献
119.
Nayandeep Deka Baruah 《Journal of Mathematical Analysis and Applications》2002,268(1):244-255
In this paper we present two new identities providing relations between Ramanujan's cubic continued fraction G(q) and the two continued fractions G(q5) and G(q7). 相似文献
120.
We report the observation of visible luminescence from HF laser irradiated absorbing gases. Preliminary studies using NH3,CH3OH and CO2 gases are described. 相似文献