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971.
Suchitra Datta 《Tetrahedron》2009,65(1):77-82
The lactam groups of dipyrrinones avidly engage in amide-amide hydrogen bonding to form dimeric association complexes in non-polar solvents (in CHCl3, KD ∼25,000 M−1 at 22 °C). The corresponding thioamides (dipyrrinthiones), prepared from dipyrrinones by reaction with Lawesson's reagent, also form intermolecularly hydrogen-bonded dimers in non-polar solvents, albeit with much weaker association constants (in CHCl3, KD ∼200 M−1 at 22 °C). When a carboxylic acid group is tethered to C(9) of the dipyrrinone, as in the hexanoic acid of [6]-semirubin, tight intramolecular hydrogen bonding between the carboxylic acid group and the lactam moiety (intramolecular Kassoc ?25,000) is found in CHCl3 with no evidence of dimers. In contrast, the analogous dipyrrinthione, [6]-thiosemirubin, eschews intramolecular hydrogen bonds, as determined using NMR spectroscopy and vapor pressure osmometry, preferring to form intermolecularly hydrogen-bonded dimers of the thioamide-thioamide type. 相似文献
972.
Let M be an open manifold with a symplectic form Ω, and N a manifold with dimN<dimM. We prove that submersions with symplectic fibres satisfy the h-principle. Such submersions define Dirac manifold structures on the given manifold. As an application to this result we show that CPn?CPk−1 admits a submersion into R2(2k−n) with symplectic fibres for n/2<k?n. 相似文献
973.
The \(\alpha \)-sandwiched Rényi divergence satisfies the data processing inequality, i.e. monotonicity under quantum operations, for \(\alpha \ge 1/2\). In this article, we derive a necessary and sufficient algebraic condition for equality in the data processing inequality for the \(\alpha \)-sandwiched Rényi divergence for all \(\alpha \ge 1/2\). For the range \(\alpha \in [1/2,1)\), our result provides the only condition for equality obtained thus far. To prove our result, we first consider the special case of partial trace and derive a condition for equality based on the original proof of the data processing inequality by Frank and Lieb (J Math Phys 54(12):122201, 2013) using a strict convexity/concavity argument. We then generalize to arbitrary quantum operations via the Stinespring Representation Theorem. As applications of our condition for equality in the data processing inequality, we deduce conditions for equality in various entropic inequalities. We formulate a Rényi version of the Araki–Lieb inequality and analyze the case of equality, generalizing a result by Carlen and Lieb (Lett Math Phys 101(1):1–11, 2012) about equality in the original Araki–Lieb inequality. Furthermore, we prove a general lower bound on a Rényi version of the entanglement of formation and observe that it is attained by states saturating the Rényi version of the Araki–Lieb inequality. Finally, we prove that the known upper bound on the entanglement fidelity in terms of the usual fidelity is saturated only by pure states. 相似文献
974.
If the face-cycles at all the vertices in a map on a surface are of same type then the map is called semi-equivelar. There are eleven types of Archimedean tilings on the plane. All the Archimedean tilings are semi-equivelar maps. If a map on the torus is a quotient of an Archimedean tiling on the plane then the map is semi-equivelar. We show that each semi-equivelar map on the torus or on the Klein bottle is a quotient of an Archimedean tiling on the plane.Vertex-transitive maps are semi-equivelar maps. We know that four types of semi-equivelar maps on the torus are always vertex-transitive and there are examples of other seven types of semi-equivelar maps which are not vertex-transitive. We show that the number of -orbits of vertices for any semi-equivelar map on the torus is at most six. In fact, the number of orbits is at most three except one type of semi-equivelar maps. Our bounds on the number of orbits are sharp. 相似文献
975.
Archana Singh Mahendra Aynyas Sankar P. Sanyal 《Central European Journal of Physics》2009,7(1):102-107
We have predicted the phase transition pressure (P
T
)and high pressure behavior of Zirconium and Niobium carbide (ZrC, NbC). The high pressure structural phase transitions in
ZrC and NbC has been studied by using a two body inter-ionic potential model, which includes the Coulomb screening effect,
due to the semi-metallic nature of these compounds. These transition metal carbides have been found to undergo NaCl (B1) to CsCl (B2)-type structural phase transition, at high pressure like other binary systems. We predict such structural transformation
in ZrC and NbC at a pressure of 98GPa and 85GPa respectively. We have also predicted second order elastic constant and bulk
modulus. The present theoretical work has been compared with the corresponding experimental data and prediction of LAPW and
GGA and LDA theories.
相似文献
976.
Aparna Datta Sayantan Dasgupta Siddhartha Mukherjee 《Journal of nanoparticle research》2017,19(4):142
In the past decade, a variety of drug carriers based on mesoporous silica nanoparticles has been extensively reported. However, their biocompatibility still remains debatable, which motivated us to explore the porous nanostructures of other metal oxides, for example titanium dioxide (TiO2), as potential drug delivery vehicles. Herein, we report the in vitro hemolysis, cytotoxicity, and protein binding of TiO2 nanoparticles, synthesized by a sol–gel method. The surface of the TiO2 nanoparticles was modified with hydroxyl, amine, or thiol containing moieties to examine the influence of surface functional groups on the toxicity and protein binding aspects of the nanoparticles. Our study revealed the superior hemocompatibility of pristine, as well as functionalized TiO2 nanoparticles, compared to that of mesoporous silica, the present gold standard. Among the functional groups studied, aminosilane moieties on the TiO2 surface substantially reduced the degree of hemolysis (down to 5%). Further, cytotoxicity studies by MTT assay suggested that surface functional moieties play a crucial role in determining the biocompatibility of the nanoparticles. The presence of NH2– functional groups on the TiO2 nanoparticle surface enhanced the cell viability by almost 28% as compared to its native counterpart (at 100 μg/ml), which was in agreement with the hemolysis assay. Finally, nonspecific protein adsorption on functionalized TiO2 surfaces was examined using human serum albumin and it was found that negatively charged surface moieties, like –OH and –SH, could mitigate protein adsorption to a significant extent. 相似文献
977.
We recently reported the use of low dose gamma irradiation to improve plant vigor, grain development and yield attributes of wheat (Singh and Datta, 2010). Further, we report here the results of a field experiment conducted to assess the effect of gamma irradiation at 0, 0.01, 0.03, 0.05, 0.07 and 0.1 kGy on flag leaf area, stomatal conductance, transpiration and photosynthetic rate and plant and grain nutritional quality. Gamma irradiation improved plant nutrition but did not improve the nutritional quality of grains particularly relating to micronutrients. Grain carotene, a precursor for vitamin A, was higher in irradiated grains. Low grain micronutrients seem to be caused by a limitation in the source to sink nutrient translocation rather than in the nutrient uptake capacity of the plant root. 相似文献
978.
Arigala Uma Ravi Sankar Mitsuji Yamasitha Kambam Srinivasulu Nobuhisa Ozaki Michio Fujie Keisuke Ogawa Manubu Yamada Motohiko Kimura 《Tetrahedron letters》2010,51(18):2431-2433
A new type of dendritic molecules, Gd-DTPA derivatives, which work as a functionalized ligand coordinating gadolinium(III) ion at the center of their frameworks with different terminal moieties on the molecular surfaces, was readily synthesized with high yield. The structures were established by 1H, 13C NMR, and mass spectral studies. In vitro studies showed them to have enhanced r1 value in albumin medium and good potentiality as MRI contrast agent. 相似文献
979.
We predict the robust existence of a novel quantum orbital stripe order in the p-band Bose-Hubbard model of two-dimensional triangular optical lattices with cold bosonic atoms. An orbital angular momentum moment is formed on each site exhibiting a stripe order both in the superfluid and Mott-insulating phases. The stripe order spontaneously breaks time-reversal, lattice translation, and rotation symmetries. In addition, it induces staggered plaquette bond currents in the superfluid phase. Possible signatures of this stripe order in the time of flight experiment are discussed. 相似文献
980.
Amitabha Datta 《Journal of chemical crystallography》2009,39(9):619-622
Abstract The copper(II) complex [Cu(C5H4NCH2−N=CH–C6H3OCH3–O)Cl], (1) containing a new tridentate Schiff base ligand (LH), which is the 1:1 condensation product of 2-(aminomethyl)pyridine and o-vaniline, has been synthesised and characterized by IR and UV–Vis spectra. Structural investigation shows that 1 crystallizes to a monoclinic system, having space group P2(1)/c, a = 6.9634(7), b = 18.1209(19), c = 10.3448(11) ?, α = 90°, β = 103.97(2)°, γ = 90° and Z = 4. The coordination geometry around the copper atom is slightly distorted square planar, formed by the N2O donor set of the Schiff base and one Cl atom. The Cu–N(1), Cu–N(2), Cu–O(1) and Cu–Cl bond distances are 2.0114(14), 1.9414(14),
1.9147(12) and 2.2520(5) ?, respectively.
Index Abstract The copper(II) complex [Cu(C5H4NCH2−N=CH–C6H3OCH3–O)Cl], (1) containing a tridentate Schiff base ligand (LH), synthesised and characterized by IR and UV–Vis spectra. The central copper
ion possesses a distorted square-planar geometry.
相似文献