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931.
Maj‐Britt Suhr Kirketerp Michael Åxman Petersen Dr. Marius Wanko Dr. Leonardo Andres Espinosa Leal Henning Zettergren Dr. Françisco M. Raymo Prof. Angel Rubio Prof. Mogens Brøndsted Nielsen Prof. Steen Brøndsted Nielsen Prof. 《Chemphyschem》2009,10(8):1207-1209
From blue to red: While four π‐conjugated nitrophenolates absorb within a relatively narrow region in solution, they cover the entire visible spectrum when isolated in vacuo (see picture). The work combines gas‐ and solution‐phase spectroscopy and provides the first benchmark of theoretical excitation energies for nitrophenolates.
932.
Kurt Brunner Maria P. Kovalsky Paris Guadalupe Paolino Hermann Bürstmayr Marc Lemmens Franz Berthiller Rainer Schuhmacher Rudolf Krska Robert L. Mach 《Analytical and bioanalytical chemistry》2009,395(5):1385-1394
In recent years, plant breeders made great progress in breeding Fusarium-tolerant wheat lines. However, total resistance to this genus of plant pathogenic fungi has not yet been achieved as the
resistance genes are located on several distinct genetic regions. Visual scoring of disease symptoms in combination with the
analysis of mycotoxins is commonly applied to assess the tolerance of new lines. Both approaches are indirect methods and
do not mandatorily determine the accumulated fungal biomass. Quantitative PCR is a useful tool to assess fungal biomass based
on the abundance of organism-specific DNA. The aim of this study was the development of a quantitative PCR assay for trichothecene-producing
Fusarium species and to adapt this method for resistance assessment of wheat lines artificially infected with Fusarium graminearum and Fusarium culmorum. Several DNA-extraction methods for wheat samples were evaluated and optimized for downstream real-time PCR analysis and
furthermore, a new reference-gene-based approach for more accurate quantification of Fusarium biomass in cereals is presented. The co-determination of a plant gene was used to compensate for unequal DNA-extraction efficiencies. 相似文献
933.
Chiara Dall’Asta Mattia Mangia Franz Berthiller Alexandra Molinelli Michael Sulyok Rainer Schuhmacher Rudolf Krska Gianni Galaverna Arnaldo Dossena Rosangela Marchelli 《Analytical and bioanalytical chemistry》2009,395(5):1335-1345
In this paper, the results obtained by five independent methods for the quantification of fumonisins B1, B2, and B3 in raw maize are reported. Five naturally contaminated maize samples and a reference material were analyzed in three different
laboratories. Although each method was validated and common calibrants were used, a poor agreement about fumonisin contamination
levels was obtained. In order to investigate the interactions among analyte and matrix leading to this lack of consistency,
the occurrence of fumonisin derivatives was checked. Significant amounts of hidden fumonisins were detected for all the considered
samples. Furthermore, the application of an in vitro digestion protocol to raw maize allowed for a higher recovery of native
fumonisins, suggesting that the interaction occurring among analytes and matrix macromolecules is associative rather than
covalent. Depending on the analytical method as well as the maize sample, only 37–68% of the total fumonisin concentrations
were found to be extractable from the samples. These results are particularly impressive and significant in the case of the
certified reference material, underlying the actual difficulties in ascertaining the trueness of a method for fumonisin determination,
opening thus an important issue for risk assessment. 相似文献
934.
Simone Budow Peter Leonard Henning Eickmeier Hans Reuter Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(3):o100-o102
The title compound [systematic name: 1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐3‐iodo‐5‐nitro‐1H‐indole], C13H13IN2O5, exhibits an anti glycosylic bond conformation with a χ torsion angle of −114.9 (3)°. The furanose moiety shows a twisted C2′‐endo sugar pucker (S‐type), with P = 141.3° and τm = 40.3°. The orientation of the exocyclic C4′—C5′ bond is +ap (gauche, trans), with a γ torsion angle of 177.4 (2)°. The extended crystal structure is stabilized by hydrogen bonding and I...O contacts, as well as by stacking interactions. The O atoms of the nitro group act as acceptors, forming bifurcated hydrogen bonds within the ac plane. Additionally, the iodo substituent forms an interplanar contact with an O atom of the nitro group, and another contact with the O atom of the 5′‐hydroxy group of the sugar moiety within the ac plane is observed. These contacts can be considered as the structure‐determining factors for the molecular packing in the crystal structure. 相似文献
935.
936.
Michael A. Henning 《Discrete Mathematics》2009,309(1):32-323
A set S of vertices in a graph G is a total dominating set of G if every vertex of G is adjacent to some vertex in S. In this paper, we offer a survey of selected recent results on total domination in graphs. 相似文献
937.
Armin Rainer 《Annals of Global Analysis and Geometry》2009,35(3):249-266
Let V be a real finite dimensional representation of a compact Lie group G. It is well known that the algebra of G-invariant polynomials on V is finitely generated, say by σ
1, . . . , σ
p
. Schwarz (Topology 14:63–68, 1975) proved that each G-invariant C
∞-function f on V has the form f = F(σ
1, . . . , σ
p
) for a C
∞-function F on . We investigate this representation within the framework of Denjoy–Carleman classes. One can in general not expect that f and F lie in the same Denjoy–Carleman class C
M
(with M = (M
k
)). For finite groups G and (more generally) for polar representations V, we show that for each G-invariant f of class C
M
there is an F of class C
N
such that f = F(σ
1, . . . , σ
p
), if N is strongly regular and satisfies
where m is an (explicitly known) integer depending only on the representation. In particular, each G-invariant (1 + δ)-Gevrey function f (with δ > 0) has the form f = F(σ
1, . . . , σ
p
) for a (1 + δm)-Gevrey function F. Applications to equivariant functions and basic differential forms are given.
相似文献
938.
Let G=(V,E) be a connected graph. A dominating set S of G is a weakly connected dominating set of G if the subgraph (V,E∩(S×V)) of G with vertex set V that consists of all edges of G incident with at least one vertex of S is connected. The minimum cardinality of a weakly connected dominating set of G is the weakly connected domination number, denoted . A set S of vertices in G is a total dominating set of G if every vertex of G is adjacent to some vertex in S. The minimum cardinality of a total dominating set of G is the total domination number γt(G) of G. In this paper, we show that . Properties of connected graphs that achieve equality in these bounds are presented. We characterize bipartite graphs as well as the family of graphs of large girth that achieve equality in the lower bound, and we characterize the trees achieving equality in the upper bound. The number of edges in a maximum matching of G is called the matching number of G, denoted α′(G). We also establish that , and show that for every tree T. 相似文献
939.
Motivated by a problem in communication complexity, we study cover-structure graphs (cs-graphs), defined as intersection graphs of maximal monochromatic rectangles in a matrix. We show that not every graph is a cs-graph. Especially, squares and odd holes are not cs-graphs.It is natural to look at graphs (beautiful graphs) having the property that each induced subgraph is a cs-graph. They form a new class of Berge graphs. We make progress towards their characterization by showing that every square-free bipartite graph is beautiful, and that beautiful line graphs of square-free bipartite graphs are just Path-or-Even-Cycle-of-Cliques graphs. 相似文献
940.
In this paper, we continue the study of paired-domination in graphs introduced by Haynes and Slater [T.W. Haynes, P.J. Slater, Paired-domination in graphs, Networks 32 (1998), 199–206]. A paired-dominating set of a graph G with no isolated vertex is a dominating set S of vertices whose induced subgraph has a perfect matching. We consider paired-dominating sets which are also locating sets, that is distinct vertices of G are dominated by distinct subsets of the paired-dominating set. We consider three variations of sets which are paired-dominating and locating sets and investigate their properties. 相似文献