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排序方式: 共有987条查询结果,搜索用时 15 毫秒
981.
Numata M Li C Bae AH Kaneko K Sakurai K Shinkai S 《Chemical communications (Cambridge, England)》2005,(37):4655-4657
We have demonstrated that the creation of novel silica nanofibers with a uniform diameter is possible by utilizing beta-1,3-glucan polysaccharide as a one-dimensional host for monoalkoxysilane; the finding establishes that beta-1,3-glucan can act not only as a novel one-dimensional host for metal alkoxide polycondensation but also as an interface between inorganic nanofibers and functional organic molecules. 相似文献
982.
Nuida T Matsuda T Tokoro H Sakurai S Hashimoto K Ohkoshi S 《Journal of the American Chemical Society》2005,127(33):11604-11605
The second harmonic generation (SHG) and magnetization-induced SHG (MSHG) of AMA[MB(CN)6]-type (F3m) Prussian blue analogues (i.e., CsCo[Cr(CN)6].0.5H2O and RbMn[Fe(CN)6]) were observed. A large interaction between the nonlinear optical response and magnetic spins was observed in CsCo[Cr(CN)6].0.5H2O. These observations of SHG and MSHG imply that AMA[MB(CN)6]-type Prussian blue analogues are piezoelectric above the Curie temperature (TC) and piezoelectric ferromagnet below TC. 相似文献
983.
Hideki Sakurai 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(8):257-269
Several polysilane block copolymers have been prepared by the newly developed method, anionic polymerization of masked disilenes. Especially amphiphilic block copolymers of poly(1,1-dimethyl-2,2-dihexyldisilene) and poly methacrylate are focused. Poly(1,1-dimethyl-2,2-dihexyldisilene)-b-poly(2-hydroxyethyl methacrylate) (PMHS-b-PHEMA) is the first example of the amphiphilic polysilane copolymer that can form micelles in polar solvents. Poly(1,1-dimethyl-2,2-dihexyldisilene)-b-poly(methacrylic acid) (PMHS-b-PMAA) is more polar than (PMHS-b-PHEMA), soluble in water to form micelles. The cross-linking reaction of (PMHS-b-PMAA) with 1,10-diaza-4,7-dioxadecane and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride afforded the first shell cross-linked micelles (SCM) of polysilane. In addition to interesting properties, SCM is indicated to be able to form hollow sphere particles (hollow shell cross-linked micelles, HSCM) by a photochemical process. Reversible encapsulation of guest molecules by SCM and HSCM is demonstrated. Finally, SCM can be used as the template for the synthesis of metal nanoparticles, which may be used as catalysts. 相似文献
984.
A comparison is made between two types of solid particles used in electrorheological fluids: particles with homogeneous electrical
properties versus layered particles with a semi-conducting core surrounded by an outer layer of lower conductivity. Rheological
measurements of these suspensions under steady shear and d.c. electric field show that the layered particle system produces
the same yield stress but with a substantially reduced electric current. X-ray spectroscopic analysis confirms that these
particles have a thin layer of SiOx on the outer surface which causes the reduction in conductivity. Measurement of the dielectric permittivity followed by analysis
using the Maxwell-Wagner model of polarization indicates that the conductivity of the outer layer is about 0.62 times that
of the core region.
Received: 13 January 1999 Accepted: 26 July 1999 相似文献
985.
986.
987.
Yuzo Kaneko Kiyotaka Sakai Akihiko Kikuchi Yasuhisa Sakurai Teruo Okano 《Macromolecular Symposia》1996,109(1):41-53
The synthesis and characterization of comb-type grafted thermo-sensitive hydrogels is presented. These hydrogels were synthesized by polymerization of N-isopropylacrylamide (IPAAm) with a PIPAAm macromonomer. This process leads to a crosslinked IPAAm backbone polymer, copolymerized with highly mobile comb-type PIPAAm chains. These new thermo-responsive copolymers displayed higher equilibrium swellings at lower temperatures and rapid deswelling kinetics at elevated temperatures. The swelling/deswelling for comb-type gels is dependent on the graft chain lengths, in contrast to normal PIPAAm gel lacking the graft chains. As the temperature is increased above the critical temperature, the dehydrated graft chains aggregated due to hydrophobic attraction. Rapid and reversible kinetics of the graft-type gel were observed in response to stepwise temperature changes within short time cycles: phenomena not observed in normal crosslinked thermo-sensitive gels. The influence of freely mobile graft chains on both the equilibrium and dynamic properties of comb-type PIPAAm gel is demonstrated. Possible application of graft-type gel is discussed for actuator systems. 相似文献