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91.
B. HRIBAR LEE V. VLACHY L. B. BHUIYAN C. W. OUTHWAITE M. MOLERO 《Molecular physics》2013,111(19):2969-2980
Monte Carlo simulation and theoretical results on some aspects of thermodynamics of mixtures of electrolytes with a common species are presented. Both charge symmetric mixtures, where ions differ only in size, and charge asymmetric but size symmetric mixtures at ionic strength ranging generally from I = 10?4 to 1.0 M, and in a few cases up to I = 2 M, are examined. The theoretical methods explored are: (i) the symmetric Poisson-Boltzmann theory, (ii) the modified Poisson-Boltzmann theory and (iii) the hypernetted-chain integral equation. The first two electrolyte mixing coefficients w 0 and w 1 of the various mixtures are calculated from an accurate determination of their osmotic pressure data. The theories are seen to be consistent among themselves, and with certain limiting laws in the literature, in predicting the trends of the mixing coefficients with respect to ionic strength. Some selected relevant experimental data have been analysed and compared with the theoretical and simulation trends. In addition the mean activity coefficients for a model mimicking the mixture of KC1 and KF electrolytes are calculated and hence the Harned coefficients obtained for this system. These calculations are compared with the experimental data and Monte Carlo results available in the literature. The theoretically predicted Harned coefficients are in good agreement with the simulation results for the model KC1-KF mixture. 相似文献
92.
A new hybrid organic-inorganic monolithic cartridge was synthesized and used as the selective sorbent for the extraction and purification of quercetin and myricetin from Chamaecyparis obtusa via a solid-phase extraction method.The morphology of the monolithic material was examined by field emission-scanning electron microscopy and a Brunauer-Emmett-Teller(BET) test.The adsorption capacity of the obtained material for quercetin and myricetin was investigated by fitting the adsorption data to four different adsorption equations,of which the LangmuirFreundlich isotherm was selected as the most suitable model.Under optimized conditions,good calibration curves were observed at nine concentrations ranged from 0.5 μg/mL to 100.0 μg/mL of quercetin and myricetin.The extraction recovery ranged from 74.5% to 84.6% and the inter-and intra-day relative standard deviations were <6%.This type of hybrid monolith has potential for the separation and purification of bioactive compounds from natural plant extracts. 相似文献
93.
XIE Jing LI Xin JIANG Chao-jun LEE Robert Jian-guang ZHOU Yu-lin TENG Le-sheng 《高等学校化学研究》2013,29(5):1003-1005
Novel poly(lactide-co-glycolide acid)(PLGA) microspheres were developed for sustained delivery of antisense oligonucleotide(ASO). First, a new cationic agent, polyethylenimine(PEI) conjugated to linoleic acid(LA)(PEI-LA) was synthesized by reacting PEI(Mw=800) with linoleoyl chloride. Then, PEI-LA was combined with LOR-2501 to form electrostatic complexes at moderate nitrogen-to-phosphate(N/P) molar ratios which were then encapsulated into poly(lactide-co-glycolide) microspheres by a multiple emulsion-solvent evaporation technique. With an increase in ASO/PEI-LA concentration from 5% to 10%, encapsulation efficiency of ASO in the microspheres reduced from 72.14% to 57.62%, and the particle size of microspheres increased from 28.58 μm to 34.76 μm. In vitro studies show that the release profile of ASO from microspheres prepared at 7.5% ASO-PEI-LA lasted for 14 d. The novel microspheres have a potential use as a sustained release vehicle for ASO. 相似文献
94.
T. S. LEE LIAO WEI H. T. LOW 《International Journal of Computational Fluid Dynamics》2013,27(3):197-208
A numerical method has been developed to solve the steady and unsteady incompressible Navier-Stokes equations in a two-dimensional, curvilinear coordinate system. The solution procedure is based on the method of artificial compressibility and uses a third-order flux-difference splitting upwind differencing scheme for convective terms and second-order center difference for viscous terms. A time-accurate scheme for unsteady incompressible flows is achieved by using an implicit real time discretization and a dual-time approach, which introduces pseudo-unsteady terms into both the mass conservation equation and momentum equations. An efficient fully implicit algorithm LU-SGS, which was originally derived for the compressible Eulur and Navier-Stokes equations by Jameson and Toon [1], is developed for the pseudo-compressibility formulation of the two dimensional incompressible Navier-Stokes equations for both steady and unsteady flows. A variety of computed results are presented to validate the present scheme. Numerical solutions for steady flow in a square lid-driven cavity and over a backward facing step and for unsteady flow in a square driven cavity with an oscillating lid and in a circular tube with a smooth expansion are respectively presented and compared with experimental data or other numerical results. 相似文献
95.
WANG Yan-hua LI Li CHEN Chia-hung CHENG Shuenn-ren LEE Mu-sheng YU Pu-ping CHANG-CHIEN Guo-ping 《高等学校化学研究》2012,28(2):195-199
Sulfonamide residue in honey existed in a form bonded to sugar via the N-glycosidic bond.It would result in the possible underestimation of concentration of sulfonamide if it is not decomposed by chemi... 相似文献
96.
97.
YANG Zunhua KIM Kyung Ran PARK Ah-Young LEE Hyung-Rock KANG Jin-Ah KIM Won Hee CHUN Pusoon GONG Ping LEE Boeun JEONG Lak Shin MOON Hyung Ryong 《中国化学》2009,27(12):2405-2412
Synthesis of north‐5'‐methylbicyclo[3.1.0]hexyl purine and pyrimidine nucleosides with an ethynyl group at C‐3' position has been successfully accomplished by a facile method. Methylbicyclo[3.1.0]hexanone (±)‐ 5 having three contiguous chiral centers was remarkably simply constructed only by four steps containing a carbenoid insertion reaction in the presence of rhodium(II) acetate dimer and CuSO4, giving a correct relative stereochemistry of the generated three chiral centers. Upon Grignard reaction of (±)‐ 5 with ethynylmagnesium bromide, exclusive diastereoselectivity was observed. Condensation of glycosyl donor (±)‐ 9 with purine nucleobase afforded only the desired N9‐alkylated nucleoside, while condensation with pyrimidine, N3‐benzoylated uracil gave the desired N1‐alkylated nucleoside (±)‐ 13 with the undesired O2‐alkylated nucleoside (±)‐ 14 . Probably, (±)‐ 14 would be formed due to steric hindrance caused upon approaching for N1‐alkylation. 相似文献
98.
99.
For the preparation of high-active and high-isospecific catalysts for propylenepolymerization,various supports such as Mg-alkyls[1 ] ,Mg( OH) 2 [2 ] ,Mg O[3] ,Mg Cl2 [4] .Grignard compounds[5] ,or magnesium alkoxide[6] had been used.Lately,Mg( OEt) 2 -supported Ti Cl4catalysts including an organic chloride and/ or an internal donor preparedby physical milling method and chemical reaction method were studied and it was foundthat Mg( OEt) 2 is converted to Mg Cl2 by reaction with Ti Cl4a… 相似文献
100.
讨论了应用高频电感耦合等离子体(ICP)消解氟里昂类废弃物的可行性及与国际先进技术的比较;应用低功率ICP系统进行氟里昂12的模拟消解,用GC-ECD方法对尾气中的残余成分和浓度进行分析,证明该系统对氟里昂12的处理效率高于99.9%,可以发展成为未来环保废物处理领域的一项新技术。 相似文献