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排序方式: 共有261条查询结果,搜索用时 62 毫秒
41.
Modi Kalpesh V. Jani Hardik K. Gamit Ilesh D. 《Journal of Thermal Analysis and Calorimetry》2021,143(2):899-913
Journal of Thermal Analysis and Calorimetry - The thermal performance of solar still can be enhanced by means of nanoparticles. The core aim of the present work is to identify the influence of... 相似文献
42.
G. Daikuhara E. Truog L. Michaelis L. T. Sharp D. R. Hoogland H. A. Noyes O. Arrhenius C. B. Lipman H. R. Christensen F. W. Parker H. Kappen A. Densch A. Rippel Th. Arnd O. Schreiner G. Loges E. Ramann F. K. Cameron R. Ulbricht W. Wolf W. Jani Biéler-Chatelan E. A. Mitscherlich C. W. Davis B. S. Davisson H. Neubauer W. Schneider Fr. Czapek G. Wunder J. K. Greisenegger K. Vorbuchner H. Niklas Hirschberger Ausschuss für Boden und Düngung des Verbandes Landwirtschaftlicher Versuchs-Stationen im Deutschen Reiche 《Analytical and bioanalytical chemistry》1924,65(6-7):273-274
43.
B. Beaumont M. Vaille T. Boufaden B. el Jani P. Gibart 《Journal of Crystal Growth》1997,170(1-4):316-320
Several nitrogen precursors have been used for the growth of GaN in MOVPE, but so far the best results were obtained using NH3, even though NH3 does not produce a significant amount of active species at the growing interface. To produce active species from N2 or NH3, a remote plasma-enhanced chemical vapour deposition (RPECVD) process has been implemented. In addition, nitrogen metalorganic precursors, triethylamine and t-butylamine, were also used. To accurately control the critical parameters of the MOVPE of GaN, we have implemented a laser reflectometry equipment, which allows a real-time in situ monitoring of the different steps of the growth, i.e. nitridation of the substrate, nucleation, heat treatment, and deposition. Using an appropriate buffer layer, GaN grown on sapphire using NH3 as nitrogen precursor, shows sharp low temperature photoluminescence lines (4 meV at 9 K), whereas other nitrogen precursors did not lead to comparable electronic quality. 相似文献
44.
Václav Janiš Jindřich Kolorenč 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(7):170
One- and two-electron Green functions are simultaneously needed to determine the responsefunctions of the electron gas in a random potential. Reliable approximations must retainconsistency between the two types of Green functions expressed via Ward identities so thattheir output is compliant with macroscopic symmetries and conservation laws. Such aconsistency is not directly guaranteed when summing nonlocal corrections to the local(dynamical) mean field. We analyze the reasons for this failure and show how the full Wardidentity can generically be implemented in the diagrammatic approach to the vertexfunctions without breaking the analytic properties of the self-energy. We use thelow-energy asymptotics of the conserving two-particle vertex determining the singular partof response and correlation functions to derive an exact representation of the diffusionconstant in terms of Green functions of the perturbation theory. We then calculateexplicitly the leading vertex corrections to the mean-field diffusion constant due tomaximally-crossed diagrams. 相似文献
45.
Jani P. J. Turunen Tapani Venäläinen Sari Suvanto Tuula T. Pakkanen 《Journal of polymer science. Part A, Polymer chemistry》2007,45(17):4002-4012
Mesoporous aluminas with average pore sizes of 4.3–7.8 nm were prepared by anodization of an aluminum film (AAO), and by a sol–gel templating method (TPL). In addition to a commercial alumina and sulfated TPL, the aluminas were used as supports for cyclopentadienyl zirconocene dichloride (Cp2ZrCl2) and trimethyl(η5‐pentamethylcyclopentadienyl)zirconium (Cp*ZrMe3) and tested in the polymerization of ethylene. The metallocenes supported on the alumina prepared with the templating method and its sulfated modification exhibited polymerization activities of 440 and 350 kgPE/(molZr × h × bar), respectively, comparable to that obtained with silica‐supported metallocenes (390 kgPE/(molZr × h × bar)). The acid site distribution of the aluminas was studied with FTIR and temperature programmed desorption (TPD) of pyridine, and also the amount of medium and strong acid sites was determined gravimetrically from the adsorption of pyridine. Relative to the surface area, AAO with the highest amount of acid sites (2.10 μmolpy/m) adsorbed Cp2ZrCl2 and Cp*ZrMe3 the most. Study of the polymers' morphology with a scanning electron microscope revealed polyethylene nanofibers in all the polymer samples, also in those obtained from the reference polymerizations with homogeneous Cp2ZrCl2 and Cp*ZrMe3. This finding suggests that a catalyst support with a tubular pore structure is not a prerequisite for the formation of polymer nanofibers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4002–4012, 2007 相似文献
46.
Optical Review - We consider probing inhomogeneous waves in the near fields of metallic nanostructures with the aid of a dielectric V-shaped wedge connected to a waveguide. A geometrical model... 相似文献
47.
H. Ben Naceur I. Moussa O. Tottereau A. Rebey B. El Jani 《Physica E: Low-dimensional Systems and Nanostructures》2009,41(10):1779-1783
Thin InAs epilayers were grown on GaAs(1 0 0) substrates exactly oriented and misoriented toward [1 1 1]A direction by atmospheric pressure metalorganic vapor phase epitaxy. InAs growth was monitored by in situ spectral reflectivity. Structural quality of InAs layers were studied by using high-resolution X-ray diffraction. No crystallographic tilting of the layers with respect to any kind of these substrates was found for all thicknesses. This result is discussed in terms of In-rich growth environment. InAs layers grown on 2° misoriented substrate provide an improved crystalline quality. Surface roughness of InAs layers depend on layer thickness and substrate misorientation. 相似文献
48.
49.
We establish the basic analytic and geometric properties of quasiregular maps f: ω → X, where ω ? ? n is a domain and X is a generalized n-manifold with a suitably controlled geometry. Generalizing the classical Väisälä and Poletsky inequalities, our main theorem shows that the path family method applies to these maps. 相似文献
50.
Saunavaara J Jokisaari J 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2006,180(1):58-62
The (129)Xe chemical shift of xenon dissolved in isotropic liquids is very sensitive to solvent density, which in turn is dependent on the sample temperature. Therefore, the (129)Xe chemical shift can be used as the basis of a thermometer for measuring actual sample temperatures in NMR experiments. Good accuracy can be achieved, but the thermometer is particularly useful in monitoring temperature stability. In the present case, carbon tetrachloride (CCl(4)), ethylbromide (C(2)H(5)Br), and deuterated chloroform (CDCl(3)) were chosen as solvents because of their large thermal expansion coefficient. 相似文献