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91.
92.
This paper considers the cobordism groups of hyperframed manifolds; that is, manifolds which are framed off a codimension one submanifold. These groups are related to thestable J-homomorphism in the same way that the cobordism groups of almost parallelizable manifolds are related to the J-homomorphism. We compute characteristic numbers and present some low dimensional examples.Research partially supported by NSF Grant MCS76–06973Research partially supported by NSF Grant MPS74–22738 相似文献
93.
A boundary initial value problem for a quasi-linear hyperbolic system in one space variable is coupled to a boundary initial value problem for a quasi-linear parabolic equation in two space variables. The coupling occurs through one of the boundary conditions for the hyperbolic system and the source term in the parabolic equation. Such a coupling can arise in the consideration of gas flowing in a porous medium and out of that medium via a pipe. A local existence and uniqueness theorem is demonstrated. The proof involves the method of characteristics, Bernstein's estimates for parabolic partial differential equations, and the contracting mapping theorem. 相似文献
94.
95.
The 1H and 13C NMR spectra of cis- and trans-2,3-dimethyloxetane have been re-examined and the published NMR assignments shown to be in error. 相似文献
96.
A coupled non-linear hyperbolic-sobolev system 总被引:1,自引:0,他引:1
Richard E. Ewing 《Annali di Matematica Pura ed Applicata》1977,114(1):331-349
Summary A boundary-initial value problem for a quasilinear hyperbolic system in one space variable is coupled to a boundary-initial
value problem for a quasilinear equation of Sobolev type in two space variables of the form Mut(x, t)+L(t) u (x, t)=f(x, t, u(x, t)) where M and L(t) are second order elliptic spacial operators. The coupling occurs through
one of the boundary conditions for the hyperbolic system and the source term in the equation of Sobolev type. Such a coupling
can arise in the consideration of oil flowing in a fissured medium and out of that medium via a pipe. Barenblatt, Zheltov,
and Kochina[2] have modeled flow in a fissured medium via a special case of the above equation. A local existence and uniqueness theorem
is demonstrated. The proof involves the method of characteristics, some applications of results of R. Showalter and the contraction
mapping theorem.
Entrata in Redazione il 28 luglio 1976. 相似文献
97.
98.
The dramatic increases in ionic conductivity in Gd2(Ti1-xZrx)2O7 solid solution are related to disordering on the cation and anion lattices. Disordering in Gd2(Ti1-xZrx)2O7 was characterized using x-ray photoelectron spectroscopy (XPS). As Zr substitutes for Ti in Gd2Ti2O7 to form Gd2(Ti1-xZrx)2O7 (0.25 < x < or =0.75), the corresponding O 1s XPS spectrum merges into a single symmetric peak. This confirms that the cation antisite disorder occurs simultaneously with anion disorder. Furthermore, the O 1s XPS spectrum of Gd2Zr2O7 experimentally suggests the formation of a split vacancy. 相似文献
99.
Prototyping disposable electrophoresis microchips with electrochemical detection using rapid marker masking and laminar flow etching 总被引:2,自引:0,他引:2
Two novel methods are described for the fabrication of components for microchip capillary electrophoresis with electrochemical detection (microchip CEEC) on glass substrates. First, rapid marker masking is introduced as a completely nonphotolithographic method of patterning and fabricating integrated thin-film metal electrodes onto a glass substrate. The process involves applying the pattern directly onto the metal layer with a permanent marker that masks the ensuing chemical etch. The method is characterized, and the performance of the resulting electrode is evaluated using catecholamines. The response compares well with photolithographically defined electrodes and exhibits detection limits of 648 nM and 1.02 microM for dopamine and catechol, respectively. Second, laminar flow etching is introduced as a partially nonphotolithographic method of replicating channel networks onto glass substrates. The replication process involves applying a poly(dimethylsiloxane) (PDMS) mold of the channel network onto a slide coated with a sacrificial metal layer and then pulling solutions of metal etchants through the channels to transfer the pattern onto the sacrificial layer. The method is tested, and prototype channel networks are shown. These methods serve to overcome the time and cost involved in fabricating glass-based microchips, thereby making the goal of a disposable high performance lab-on-a-chip more attainable. 相似文献
100.
The efficiency of chloride reactant ion formation, when chlorinated hydrocarbon reagent chemicals were added to the ionization region of an ion mobility spectrometer, corresponded to the electron attachment rate constant of the chemical. The chemicals investigated here included chloromethane, dichlormethane, trichloromethane, tetrachloromethane and chlorobenzene, with tetrachloromethane producing the greatest amount of chloride reactant ions for the amount of chemical added. Reagent chemicals with smaller electron attachment rate constants required the addition of more chemical to reach functional reactant ion levels. The excess neutral reagent molecules clustered to the chloride reactant ions and reduced the effectiveness of abstracting a proton from 2,4,6-trinitrotoluene (TNT). The effect of clustering was different for each chemical. Tetrachloromethane, which had the least exothermic clustering reaction, had the most effective production of the (TNT-H)(-) product ion per mole of reagent chemical. Bromide and iodide ions were also investigated as potential reactant ions. Bromide was found to effectively produce the proton abstracted (TNT-H)(-) ion. Iodide, however, was not a strong enough base to form (TNT-H)(-) from TNT. There was no apparent transfer of an electron to TNT by chloride, bromide or iodide. 相似文献