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721.
Summary The lipophilicity (hydrophobicity) of some alkylamines and arylamines was determined with reversed-phase thin-layer chromatography using various water: methanol mixtures as eluent with and without adding salt to the system. The effect of various structural parameters of amines and that of the chromatographic conditions were assessed with stepwise regression analysis. The calculation proved that in case of alkylamines the lipophilicity does not depend linearly on the length of the alkyl chain, the effect of methanol and salt concentrations are intercorrelated and the influence of the alkyl chain branching is negligible. In case of arylamines the number of amino groups has the highest impact on the retention and the effect of methanol and salt is also intercorrelated. 相似文献
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723.
Tibor Bisztriczky 《Mathematische Annalen》1979,243(3):191-195
724.
The excitation temperature functions of 19 spectrum lines of 5 rare gases He, Ne, Ar, Kr, Xe have been calculated according to the method given by Fowler and Milne. The results make it possible to determine the radial plasma temperature distribution in the range of temperatures of 1.4 × 104°K to 14 × 104°K. Some examples are given for the determination of the plasma temperature distribution in space and time by using the Ar ecxitation temperature functions calculated. 相似文献
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727.
Jrgen Bang-Jensen Tibor Jordn 《Journal of Algorithms in Cognition, Informatics and Logic》2000,37(2):326
Splitting off a pair su, sv of edges in a graph G means the operation that deletes su and sv and adds a new edge uv. Given a graph G = (V + s, E) which is k-edge-connected (k ≥ 2) between vertices of V and a specified subset R V, first we consider the problem of finding a longest possible sequence of disjoint pairs of edges sx, sy, (x ,y R) which can be split off preserving k-edge-connectivity in V. If R = V and d(s) is even then a well-known theorem of Lovász asserts that a complete R-splitting exists, that is, all the edges connecting s to R can be split off in pairs. This is not the case in general. We characterize the graphs possessing a complete R-splitting and give a formula for the length of a longest R-splitting sequence. Motivated by the connection between splitting off results and connectivity augmentation problems we also investigate the following problem that we call the split completion problem: given G and R as above, find a smallest set F of new edges incident to s such that G′ = (V + s, E + F) has a complete R-splitting. We give a min-max formula for F as well as a polynomial algorithm to find a smallest F. As a corollary we show a polynomial algorithm which finds a solution of size at most k/2 + 1 more than the optimum for the following augmentation problem, raised in [[2]]: given a graph H = (V, E), an integer k ≥ 2, and a set R V, find a smallest set F′ of new edges for which H′ = (V, E + F′) is k-edge-connected and no edge of F′ crosses R. 相似文献
728.
Dr. Shenglai Yao Dr. Tibor Szilvási Dr. Yun Xiong M. Sc. Christian Lorent Prof. Dr. Ales Ruzicka Prof. Dr. Matthias Driess 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22227-22231
The first series of bis(silylene)-stabilized nitrogen(I) compounds is described. Starting from the 1,2-bis(N-heterocyclic silylenyl) 1,2-dicarba-closo-dedocaborane(12) scaffold 1 , [1,2-(LSi)2C2B10H10; L=PhC(NtBu)2], reaction with adamantyl azide (AdN3) affords the terminal N-μ2-bridged zwitterionic carborane-1,2-bis(silylium) AdN3 adduct 2 with an open-cage dianionic nido-C2B10 cluster core. Remarkably, upon one-electron reduction of 2 with C8K and liberation of N2 and adamantane, the two silylene subunits are regenerated to furnish the isolable bis(silylene)-stabilized NI complex as an anion of 3 with the nido-C2B10 cluster cage. On the other hand, one-electron oxidation of 2 with silver(I) yields the monocationic bis(silylene) NI complex 4 with the closo-C2B10 cluster core. Moreover, the corresponding neutral NI radical complex 5 results from single-electron transfer from 3 to 4 . 相似文献
729.
Árpád Bihari Zoltán Dezső Tibor Bujtás László Manga András Lencsés Péter Dombóvári 《Isotopes in environmental and health studies》2014,50(1):94-102
Fission products, especially 131I, 134Cs and 137Cs, from the damaged Fukushima Dai-ichi nuclear power plant (NPP) were detected in many places worldwide shortly after the accident caused by natural disaster. To observe the spatial and temporal variation of these isotopes in Hungary, aerosol samples were collected at five locations from late March to early May 2011: Institute of Nuclear Research, Hungarian Academy of Sciences (ATOMKI, Debrecen, East Hungary), Paks NPP (Paks, South-Central Hungary) as well as at the vicinity of Aggtelek (Northeast Hungary), Tapolca (West Hungary) and Bátaapáti (Southwest Hungary) settlements. In addition to the aerosol samples, dry/wet fallout samples were collected at ATOMKI, and airborne elemental iodine and organic iodide samples were collected at Paks NPP. The peak in the activity concentration of airborne 131I was observed around 30 March (1–3 mBq m?3 both in aerosol samples and gaseous iodine traps) with a slow decline afterwards. Aerosol samples of several hundred cubic metres of air showed 134Cs and 137Cs in detectable amounts along with 131I. The decay-corrected inventory of 131I fallout at ATOMKI was 2.1±0.1 Bq m?2 at maximum in the observation period. Dose-rate contribution calculations show that the radiological impact of this event at Hungarian locations was of no considerable concern. 相似文献
730.