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31.
This paper reports the method of preparation and the emission level assignments for the light emitting powder phosphors of CaS:Er3+ and CaS:Tb3+. The recorded photoluminescence spectra of these powder phosphors have shown that the light emission would be better at lower dopant concentrations. 相似文献
32.
The new enhancement in the determination of pH using optical fiber system is described here. This work uses the membrane made of cellulose acetate membrane for reagent immobilization and congo red (pKa 3.7) and neutral red (pKa 7.2) as pH indicators. An effective covalent chemical binding procedure is used to immobilize the indicators. The response time, reversibility, linear range, reproducibility, and long-term stability of fiber optic sensor with congo red as well as neutral red have been determined. The linear range measured for the sensor based on the congo red and neutral red is 4.2-6.3 and 4.1-9.0, respectively. The response time of sensor membrane is measured by varying the substance pH values between 11.0 and 2.0. 相似文献
33.
Let M be an irreducible projective variety defined over an algebraically closed field k, and let EG be a principal G-bundle over M, where G is a connected reductive linear algebraic group defined over k. We show that for EG there is a naturally associated conjugacy class of Levi subgroups of G. Given a Levi subgroup H in this conjugacy class, the principal G-bundle EG admits a reduction of structure group to H. Furthermore, this reduction is unique up to an automorphism of EG. 相似文献
34.
Matt J. Kipper Soenke Seifert P. Thiyagarajan Balaji Narasimhan 《Journal of Polymer Science.Polymer Physics》2005,43(5):463-477
Synchrotron small‐angle X‐ray scattering (SAXS) was used to study the isothermal crystallization kinetics of a family of polyanhydride copolymers consisting of 1,6‐bis(p‐carboxyphenoxy)hexane and sebacic acid monomers. In situ SAXS experiments permitted the direct observation of the crystallization kinetics. The structural parameters (the long period, lamellar thickness, and degree of crystallinity) were obtained from Lorentz‐corrected intensity profiles, one‐dimensional correlation functions, and interface distribution functions to form a comprehensive picture of the crystal morphology. The combination of these three analyses provided information not only on the lamellar dimensions but also on the polydispersity (nonuniformity) of these dimensions. Where possible, the crystallization kinetics were interpreted with a modified version of the Avrami equation. The results can be used to perform the rational design of controlled‐drug‐release formulations because crystallinity affects drug‐release kinetics. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 463–477, 2005 相似文献
35.
Balaji V. S. Iyer Sachin Shanbhag Vinay A. Juvekar Ashish K. Lele 《Journal of Polymer Science.Polymer Physics》2008,46(21):2370-2379
In a topologically constraining environment the size of a flexible nonconcatenated ring polymer (macrocycles) and its dynamics are known to differ from that of linear polymers. Hence, the diffusion coefficient of ring polymers can be expected to be different from linear chains. We present here scaling arguments for the concentration and molecular weight dependence of self‐diffusion coefficient of ring polymers in semidilute solutions, and show that contrary to expectations these scaling relations are identical to what is known for linear polymers. At higher concentrations excluded volume interactions arising from possibilities of segmental overlap can become effective for large ring polymers. In this regime the diffusion coefficient of large ring polymers shows a relatively weaker dependence on concentration and molecular weight. ©2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2370–2379, 2008 相似文献
36.
V Balaji 《Proceedings Mathematical Sciences》1988,98(1):1-24
LetX be a smooth irreducible projective curve of genusg over the field of complex numbers. LetM 0 be the moduli space of semi-stable vector bundles onX of rank two and trivial determinant. A canonical desingularizationN o ofM o has been constructed by Seshadri [17]. In this paper we compute the third and fourth cohomology groups ofN o. In particular we give a different proof of the theorem due to Nitsure [12], that the third cohomology group ofN o is torsion-free. 相似文献
37.
Castelino K Kannan B Majumdar A 《Langmuir : the ACS journal of surfaces and colloids》2005,21(5):1956-1961
The surface grafting density of biomolecules is an important factor for quantitative assays using a wide range of biological sensors. We use a fluorescent measurement technique to characterize the immobilization density of thiolated probe DNA on gold and hybridization efficiency of target DNA as a function of oligonucleotide length and salt concentration. The results indicate the dominance of osmotic and hydration forces in different regimes of salt concentration, which was used to validate previous simulations and to optimize the performance of surface-stress based microcantilever biosensors. The difference in hybridization density between complementary and mismatched target sequences was also measured to understand the response of these sensors in base-pair mismatch detection experiments. Finally, two different techniques for immobilizing proteins on gold were considered and the surface densities obtained in both cases were compared. 相似文献
38.
Extension of Baldwin's rules for ring closure to dioxolane formation and related reactions has been attempted. A plausible mechanism has been arrived at on the basis of available literature evidence and earlier work reported from our laboratory. 相似文献
39.
[graph: see text] 1-(Beta-D-galactopyranosyl-1'-deoxy-1'-iminomethyl)-2-hydroxynaphthalene (L1), possessing an ONO binding core, was found to be selective for Cu2+ ions in N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid] buffer, at concentrations < or = 580 ppb, at physiological pH by eliciting switch-on behavior, whereas the other ions, viz., Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Zn2+, and Cd2+, caused no significant change in the fluorescence. Whereas the binding characteristics were ascertained by absorption spectroscopy, the species formed were shown by Q-TOF ES MS. 相似文献
40.
Siva Rama Krishnan Balaji Devarajan Mutharasu Subramani Shanmugan N. Sankara Subramanian Kulathu Ramanathan 《Ionics》2010,16(4):351-360
LiSmxMn2–xO4 samples were synthesized via co-precipitation technique. The structural properties of the synthesized materials were studied
using X-ray diffraction analysis and it confirmed the cubic spinel structure for all the compounds. The lattice parameter
of LiMn2O4 was observed to be 8.2347 Ǻ and it decreased with Sm3+ concentration, due to the shrinkage in cell volume aided by higher binding energy between Sm-O bond. The SEM micrographs
were analyzed using Image processing software (Image-J) to ascertain the pore and grain properties. The microwave synthesis
had been observed to control the bulk grain formation and had yielded lesser porous and nanoparticles. The particle size distributions
obtained through photocross correlation laser diffraction analysis had shown that LiMn2O4 with 60 nm and Sm-doped compounds with ∼30 nm, respectively. The cyclic voltammetry studies had revealed the decrease in
electrocatalytic behavior in the initial cycle for compounds doped with Sm3+ ion. The initial capacities of LiMn2O4, LiSm0.05Mn1.95O4 and LiSm0.10Mn1.90O4 substituted compounds were observed to be 134.87 mAhg−1, 132.22 mAhg−1 and 126.41 mAhg−1, respectively. The cells were simulated using 1D model namely Dualfoil5.1 program. The simulated results coincide well with
the measured results. The cycle life studies reveal 93% capacity retention of samarium-0.05-doped samples when compared with
78.4% of the LiMn2O4. 相似文献