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81.
Nonlinear Dynamics - The firing activities of multiple timescale dynamics for single neurons can be treated with fractional-order derivative. It has been shown in previous studies (theoretical and... 相似文献
82.
Fractional-order dynamics is applicable to biological excitable systems with strong interactions or systems with long-term memory effect. The activity of neural membrane voltage depends on the long-range correlations of ionic conductances. Such a behavior of the membrane voltage with long-range correlation can be better described with a fractional-order dynamics. A fractional-order coupled modified three-dimensional (3D) Morris–Lecar (M–L) neural system has been presented to show the variations in the firing patterns from resting state \( \rightarrow \) oscillatory pattern \( \rightarrow \) bursting and the synchronous behavior by designing a bidirectional coupling mechanism. The fractional exponents are lying between 0 and 1. The predominant controller of the changes of firing behavior is the fractional exponent. The stability of synchronization and nature of the fractional system dynamics have been analyzed. To make the investigations more convincing and biologically plausible, we consider a network of M–L oscillators with bidirectional synaptic coupling functions using global type connections and present the effectiveness of the coupling scheme. 相似文献
83.
用一组方程式描述均匀平板状生物组织的热传导,分析其分布式的最优控制问题,研究该生物组织在肿瘤局部特殊点上达到所必需的温度,通过控制微波,使微波辐射的诱导作用,在手术进程的总时间内,该肿瘤点达到过高热.研究在手术过程不同时间点上生物组织温度与其长度间的依赖关系,使肿瘤达到期望的温度值. 相似文献
84.
With a view to exploring new soliton-like solutions of certain types of nonlinear diffusion-reaction (DR) equations with a variable coefficient, we demonstrate the viability of a method which is the combination of both the symbolic computation technique of Gao and Tian [Y.T. Gao, B. Tian, Comput. Phys. Commun. 133 (2001) 158] and auxiliary equation method of Sirendaoreji [Sirendaoreji, Phys. Lett. A 356 (2006) 124] and used recently for the KdV equation. In particular, the DR equations with quadratic and cubic nonlinearities with a time-dependent velocity in the convective flux term are studied and the existence of soliton-like solutions is shown. 相似文献
85.
Upadhyay Ranjit Kumar Chatterjee Sourin Saha Satvik Azad Rajeev K. 《Nonlinear dynamics》2020,101(3):1921-1932
Nonlinear Dynamics - Robust testing and tracing are key to fighting the menace of coronavirus disease 2019 (COVID-19). This outbreak has progressed with tremendous impact on human life, society and... 相似文献
86.
Exploring amino acid‐tethered polymethacrylates as CO2‐sensitive macromolecules: A concealed property
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Kamal Bauri Abhishek Pan Ujjal Haldar Amal Narayanan Priyadarsi De 《Journal of polymer science. Part A, Polymer chemistry》2016,54(17):2794-2803
Carbon dioxide (CO2)‐responsive polymers have been gaining considerable interest because of their reactions with CO2, giving rise to gas‐switchable properties, which can easily be reversed by mild heating or purging with inert gases. Herein, the synthesis of a series of side‐chain amino acids (alanine, leucine, isoleucine, phenylalanine, tryptophan) appending poly(meth)acrylates carrying primary amine (? NH2) groups via reversible addition‐fragmentation chain transfer (RAFT) polymerization method was reported. It was found that alanine, leucine, isoleucine containing polymers displayed solubility–insolubility transition behavior and their associated property changes (solution transmittance, electrical conductivity, pH, zeta potential, and hydrodynamic diameter) in water upon alternate bubbling of CO2/N2 at room temperature. Among the three CO2‐sensitive polymers only leucine based macromolecule was further chain extended with a thermoresponsive motif, di(ethylene glycol) methyl ether methacrylate (DEGMMA), via RAFT polymerization. CO2‐tunable lower critical solution temperature and self‐assembling behavior of the diblock copolymer was carefully examined by UV–vis, 1H NMR spectroscopy, dynamic light scattering (DLS), and field emission‐scanning electron microscopy (FE‐SEM) to establish dual thermo and gas‐tunable flip–flop micellizaion from the as‐synthesized block copolymer. Formation of polyammonium methacrylate bearing bicarbonate as counter anion is responsible for pendant primary amine containing polymer induced CO2‐responsiveness. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2794–2803 相似文献
87.
Kinetics of Stripping Ni(II) from the Ni‐BTMPPA Complex/BTMPPA/Kerosene System by Sulfate‐Acetato Solution
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The kinetics of stripping of Ni2+ from a Ni‐BTMPPA complex, dissolved in a kerosene solution of BTMPPA (H2A2, Cyanex 272), by acidic sulfate‐acetato solution, was studied using the single (falling) drop technique and flux (F) method of data treatment. The empirical flux equation at 303 K is Fb (kmol/m2s) = 10?4.35 [Ni2+] (1+10?3.42 [H+]?1)?1 ([H2A2](o)0.5+2.50 [H2A2](o))?1 (1+6[SO42?]) (1+3.20 [Ac?]). Activation energy (Ea), entropy change in activation (ΔS±), and enthalpy change in activation (ΔH±) were measured under different experimental conditions. Based on the empirical flux equation, Ea and ΔS±, the mechanism of Ni2+ stripping is provided. In a low [H+] region, the stripping reaction steps appear as [NiA+] → Ni2+ + A? and [Ni(HA2)2](int) → [NiHA2]+(int) + HA2(int)? in lower and higher concentration regions of free BTMPPA, respectively, provided [SO42?] and [Ac?] are kept low. However, at higher [H+] concentrations, the stripping is under diffusion control. With increasing [SO42?] and [Ac?], the enhancement of the rate is attributed to the attack of the Ni(II) complex by SO42? or HSO4? and Ac? to form NiSO4 or NiHSO4+ and NiAc+ complexes. Negative ΔS± values indicate that the rate‐determining stripping reaction steps occur via an substitution nucleophilic, bimolecular (SN2) mechanism. 相似文献
88.
The stable complexes of amino acids with rare earths have found importance in the separation of these metals1. The complexation reactions of a number of dipeptides with copper and nickel have been reported in the literature2 – 9; but little work appears to have been done with rare earth metals. This paper is a continuation of our earlier communication10, and deals with the study of complexes of Gd3+, Dy3+, Er 3+ and Yb3+ with Glycyl-DL-valine. The Calvin—Bjerrum11, 12 pH titration technique, as modified by Irving and Rossotti13, has been employed. 相似文献
89.
Dr. Ranjit Singh Sandhu 《Monatshefte für Chemie / Chemical Monthly》1977,108(1):51-55
The thermodynamic stability constants and thermodynamic parameters for complexation reaction of Y3+, La3+, and Ce3+ with tyrosine have been determined pH metrically. The study reveals the formation of 11 complexes for La3+ and Ce3+ whereas Y3+ yields both 11 and 12 complexes. The values of enthalpy changes (H
o) indicate that unionised hydroxy group also participates in complexation. 相似文献
90.
V. Gopalakrishnan P. S. Dhami A. Ramanujam M. V. Balarama Krishna M. S. Murali J. N. Mathur R. H. Iyer A. K. Bauri A. Banerji 《Journal of Radioanalytical and Nuclear Chemistry》1995,191(2):279-289
Bench-Scale studies on the partitioning and recovery of minoractinides from the actual and synthetic sulphate-bearing high level waste (SBHLW) solutions have been carried out by giving two contacts with 30% TBP to deplete uranium content followed by four contacts with 0.2M CMPO+1.2M TBP in dodecane. The acidity of the SBHLW solutions was about 0.3M. In the case of actual SBHLW, the final raffinate contained about 0.4% -activity originally present in the HLW, whereas with synthetic SBHLW the -activity was reduced to the background level.144Ce is extracted almost quantitative in the CMPO phase,106Ru about 12% and137Cs is practically not extracted at all. The extraction chromatographic column studies with synthetic SBHLW (aftertwo TBP contacts) has shown that large volume of waste solutions could be passed through the column without break-through of actinide metal ions. Using 0.04M HNO3>99% Am(III) and rare earths could be eluted/stripped. Similarly >99% Pu(IV) and U(VI) could be eluted.stripped using 0.01M oxalic acid and 0.25M sodium carbonate, respectively. In the presence of 0.16M SO
4
2–
(in the SBHLW) the complex ions AmSO
4
+
, UO2SO4, PuSO
4
2+
and Pu(SO4)2 were formed in the aqueous phase but the species extracted into the organic phase (CMPO+TBP) were only the nitrato complexes Am(NO3)3·3CMPO, UO2(NO3)2·2CMPO and Pu(NO3)4·2CMPO. A scheme for the recovery of minor actinides from SBHLW solution with two contacts of 30% TBP followed by either solvent extraction or extraction chromatographic techniques has been proposed. 相似文献