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171.
Blends of POSS-PEO(n=4)(8) and high molecular weight poly(ethylene oxide) as solid polymer electrolytes for lithium batteries 总被引:1,自引:0,他引:1
Solid polymer electrolyte blends were prepared with POSS-PEO(n=4)8 (3K), poly(ethylene oxide) (PEO(600K)), and LiClO4 at different salt concentrations (O/Li = 8/1, 12/1, and 16/1). POSS-PEO(n=4)8/LiClO4 is amorphous at all O/Li investigated, whereas PEO(600K) is amorphous only for O/Li = 8/1 and semicrystalline for O/Li = 12/1 and 16/1. The tendency of PEO(600K) to crystallize limited the amount of POSS-PEO(n=4)(8) that could be incorporated into the blends, so that the greatest incorporation of POSS-PEO(n=4)(8) occurred for O/Li = 8/1. Blends of POSS-PEO(n=4)(8)/PEO(600K)/LiClO4 (O/Li = 8/1 and 12/1) microphase separated into two amorphous phases, a low T(g) phase of composition 85% POSS-PEO(n=4)(8)/15% PEO(600K) and a high T(g) phase of composition 29% POSS-PEO(n=4)(8)/71% PEO(600K). For O/Li = 16/1, the blends contained crystalline (pure PEO(600K)), and two amorphous phases, one rich in POSS-PEO(n=4)(8) and one rich in PEO(600K). Microphase, rather than macrophase separation was believed to occur as a result of Li(+)/ether oxygen cross-link sites. The conductivity of the blends depended on their composition. As expected, crystallinity decreased the conductivity of the blends. For the amorphous blends, when the low T(g) (80/20) phase was the continuous phase, the conductivity was intermediate between that of pure PEO(600K) and POSS-PEO(n=4)(8). When the high T(g) (70/30, 50/50, 30/70, and 20/80) phase was the continuous phase, the conductivity of the blend and PEO(600K) were identical, and lower than that for the POSS-PEO(n=4)(8) over the whole temperature range (10-90 degrees C). This suggests that the motions of the POSS-PEO(n=4)(8) were slowed down by the dynamics of the long chain PEO(600K) and that the minor, low Tg phase was not interconnected and thus did not contribute to enhanced conductivity. At temperatures above T(m) of PEO(600K), addition of the POSS-PEO(n=4)(8) did not result in conductivity improvement. The highest RT conductivity, 8 x 10(-6) S/cm, was obtained for a 60% POSS-PEO(n=4)(8)/40% PEO(600K)/LiClO4 (O/Li = 12/1) blend. 相似文献
172.
V. T. Aher M. M. Palrecha A. V. Kulkarni G. C. Shah P. K. Mathur 《Fresenius' Journal of Analytical Chemistry》1999,364(4):362-364
A differential pulse voltammetric (DPV) method is proposed for the determination of palladium in deoxo catalysts, which are
used in recombination units of the cover gas system of nuclear reactors. The electrode system consists of hanging mercury
drop electrode (HMDE)/ platinum auxillary/ Ag-AgCl reference electrode. The supporting electrolyte consists of 0.02 M diammonium
tartrate + 0.08 M ammonia-ammonium chloride buffer at pH 9.0. Fe, Cu, Pb, Ni, Co and Zn did not interfere. The interference
by Cd could be eliminated using 0.005 M EDTA. The relative standard deviation of the proposed method was about 4.0% at ∼ 0.5%
palladium content in the catalyst. The method is simple, rapid and free from any possible interferences.
Received: 8 December 1998 / Revised: 11 January 1999 / Accepted: 18 January 1999 相似文献
173.
Darshan C. Kundaliya Reeta Vij D. G. Kuberkar R. G. Kulkarni 《Physica C: Superconductivity and its Applications》2000,340(4):317-322
The structural and superconducting properties of single-phase Fe-substituted La2.5Nd0.5CaBa3(Cu1−xFex)7Oz (LNCBCuFe) with 0.0x0.06 compounds having triple-perovskite structure are investigated using X-ray diffraction, a.c. susceptibility, d.c. magnetization, oxygen content and Mössbauer effect measurements. Mössbauer spectral analysis of x=0.03 sample displays unusual Fe-dopant site occupancies and the Cu(2) plane to Cu(1) chain site ratio in the LNCBCuFe are quite different from those of the usual Fe-doped YBa2Cu3O7−δ. Specifically, we observe substantial occupation of a new chain-associated quasi-octahedral site, E, at 300 K which transforms into the well-known distorted tetrahedron chain site, A, on lowering the temperature to 78 K. The observed reduction of Tc with increasing x in LNCBCuFe supports the view that the hole filling mechanism contributes predominantly to the suppression of superconductivity by Fe. 相似文献
174.
175.
Rashmi C. Kulkarni S. Samundeeswari Farzanabi Shaikh Nirmala S. Naik Jyoti M. Madar Lokesh A. Shastri Vinay A. Sunagar 《Journal of fluorescence》2017,27(5):1613-1619
A variety of new coumarin derivatives containing C-4 bridged 2,6-dicyanoanilines (4a-4d) were synthesized via multicomponent one pot approach. These novel sensors were characterized by spectral analysis and a series of pH sensing fluorescence studies were performed, the results indicating that the sensors are highly selective and more effective at various pH. The fluorescence colour changes at different pH could be directly detected by naked eyes. 相似文献
176.
In this investigation, we have characterized the Na2SO4 using differential scanning calorimetry (DSC). It is well known that Na2SO4 exhibits five polymorphs. However, the experimental evidence for all five polymorphs has never been observed in DSC. In this
investigation, the five polymorphic transformations have been observed in heating cycle. Furthermore, the transition I–II
is observed, which is not reversible. In addition, phase transition temperature for V→IV and IV→III transition appears to
be much closed and may get unnoticed. 相似文献
177.
Airborne single-wall carbon nanotubes (SWCNTs) have a high tendency to agglomerate due to strong interparticle attractive
forces. The SWCNT agglomerates generally have complex morphologies with an intricate network of bundles of nanotubes and nanoropes,
which limits their usefulness in many applications. It is thus desirable to produce SWCNT aerosol particles that have well-defined,
unagglomerated fibrous morphologies. We present a method to generate unagglomerated, fibrous particles of SWCNT aerosols using
capillary electrospray of aqueous suspensions. The effects of the operating parameters of capillary electrospray such as strength
of buffer solution, capillary diameter, flow rate, and colloidal particle concentration on the size distributions of SWCNT
aerosols were investigated. Results showed that electrospray from a suspension of higher nanotube concentration produced a
bimodal distribution of SWCNT aerosols. Monodisperse SWCNT aerosols below 100 nm were mostly non-agglomerated single fibers,
while polydisperse aerosols larger than 100 nm had two distinct morphologies: a ribbon shape and the long, straight fiber.
Possible mechanisms are suggested to explain the formation of the different shapes, which could be used to produce SWCNT aerosols
with different morphologies. 相似文献
178.
179.
Novel fused heterocycles 1,10-dioxa-cyclopenta[a]fluorene and benzo[b]naphtho[2, 1-d]furans were synthesized via Dötz intramolecular benzannulation of alkyne tethered aryloxy chromium Fischer carbenes. 相似文献
180.
Manantesha Basanagouda Manohar V. Kulkarni Deepak Sharma Vivek K. Gupta 《Journal of chemical crystallography》2011,41(4):541-544