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61.
In an effort to build effective photovoltaic cells based on porphyrin-functionalised polythiophenes we have focused on synthetic routes to three monomer types. By controlling the geometric structure of the monomer, oxidation of these materials should produce polymers with different architectural structures, and as a result, different opto-electronic properties. Employing Wittig protocols allowed access to monomers in which the porphyrin moiety is connected to the beta-position of the thiophene via an alkene linkage. In addition, monomers were constructed using porphyrin condensation methods to afford alpha-thiophene meso-substituted porphryins. Another set of monomers was also prepared via porphyrin condensation routes, but instead utilising beta-formylthiophenes. By utilising different formyloligothiophenes we were able to generate a series of monomers that can be used to control the loading of the porphyrin in the polythiophene matrix. 相似文献
62.
Taglialatela-Scafati O Deo-Jangra U Campbell M Roberge M Andersen RJ 《Organic letters》2002,4(23):4085-4088
The known antimitotic agent eleutherobin and the briarane diterpenoids erythrolides A and B have been isolated from cultured specimens of Erythropodium caribaeorum in amounts comparable to those reported from wild-harvested reef animals. The novel diterpenoid aquariolide A, having an unprecedented highly rearranged carbon skeleton (named aquariane), has also been found. The aquariane skeleton can be formally derived from the briarane skeleton by sequential di-pi-methane and vinyl-cyclopropane rearrangements. [structure: see text] 相似文献
63.
64.
Fine structure is reported in the 69,71Ga NQR spectra of GaS and GaSe. The 69Ga (I = 32) and 71Ga (I = 32) spectra are different for each compound. This is attributed to an indirect spin-spin interaction between nearest-neighbour Ga atom pairs. A model giving reasonable quantitative agreement with experiment is presented. 相似文献
65.
Hanna C. Wentz Grigorii Skorupskii Ana B. Bonfim Jenna L. Mancuso Christopher H. Hendon Evan H. Oriel Graham T. Sazama Michael G. Campbell 《Chemical science》2020,11(5):1342
Redox-active metal–organic frameworks (MOFs) are promising materials for a number of next-generation technologies, and recent work has shown that redox manipulation can dramatically enhance electrical conductivity in MOFs. However, ligand-based strategies for controlling conductivity remain under-developed, particularly those that make use of reversible redox processes. Here we report the first use of ligand n-doping to engender electrical conductivity in a porous 3D MOF, leading to tunable conductivity values that span over six orders of magnitude. Moreover, this work represents the first example of redox switching leading to reversible conductivity changes in a 3D MOF.Redox-active ligands are used to reversibly tune electrical conductivity in a porous 3D metal–organic framework (MOF). 相似文献
66.
S. E. Campbell H. Yang R. Patel S. E. Friberg P. A. Aikens 《Colloid and polymer science》1997,275(3):303-306
The kinetics of vesicle formation from a hydrotrope (sodium xylenesulfonate) solution of a surfactant (Laureth 4) is studied
by the use of a stopped-flow apparatus combined with a dynamic light scattering device to determine vesicle size in the system.
The hydrotrope system studied presents a system with a high surfactant solubilization combined with vesicle formation simply
by dilution with water. The kinetic results show a single exponential decay time. The kinetic analysis indicates that the
vesicles are formed from a molecular solution which resulted from the shear in the stopped-flow device and grow by monomeric
association.
Received: 1 October 1996 Accepted: 22 November 1996 相似文献
67.
G. P. Kayfus T. E. Boothe J. A. Campbell R. D. Finn A. J. Gilson 《Journal of Radioanalytical and Nuclear Chemistry》1982,68(1-2):269-276
Because of the cost and limited availability of isotopically enriched thallium (>92%203Tl), its use in the203Tl(p, 3n)201Pb nuclear reaction necessitates chemical recovery. An adaptive method has been developed and evaluated. After the separation
of201Pb, the203Tl(I) is oxidized to203Tl(III) by Cl2, Br2 or [Fe(CN)6]−2, precipitated as Tl(OH)3 with NaOH and subsequently converted to Tl2O3 by heating. Due to potential loss during recovery, the solubilities of Tl(OH)3 and Tl2O3 in aqueous solution as a function of pH have been studied using the internal tracer202Tl (T=12.2d), produced during cyclotron irradiation. Effective solubility product constants have been determined to be 5.4·10−48 and 2.5·10−47 for Tl(OH)3 and Tl2O3, respectively. 相似文献
68.
Selenimn(IV) can be titrated in the range 0.2–6 mg with thiosulphate; relative standard deviations are 1.2–0.54%. Experimental conditions were manipulated to use the endothermic enthalpy of dilution and disproportionation of thiosulphate to advantage in improving end-point precision. Common anions do not interfere; interferences from copper(II), iron(III), lead(II) and mercury(II) can be minimized by masking. 相似文献
69.
E. E. B. Campbell R. R. Schneider A. Hielscher A. Tittes R. Ehlich I. V. Hertel 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,22(2):521-527
The collisional velocity dependence of the cross sections for fragmentation of mass-selected (CO2) n + (n+2...7) clusters in collisions with Ar atoms is presented. Interesting structure can be observed in the cross sections which indicate that the collision occurs between the Ar atom and one CO2 molecule within the cluster. The results may be explained by assuming that the collision leads to either vibrational excitation of a loosely bound CO2 monomer which then leaves the cluster or excitation of the entire cluster to a dissociative state. 相似文献
70.
The pressure dependence of the reorientational correlation function for chloroform has been measured by analysis of the Raman 3019 cm? 1 A1 CH stretching lineshape at 1, 1000, and 2000 bar and 23°C. These reorientational correlation functions were obtained using the method of spectral Fourier deconvolution introduced by Bratos. The results are compared to the correlation times obtained from the NMR deuteron T1 relaxation times for CDCl3 and those calculated from high pressure viscosity measurements. 相似文献