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491.
In this note we prove that the parametric fundamental equation of information is stable in the sense of Hyers and Ulam provided
that the parameter is nonpositive. We also prove, as a corollary, that the system of equations that defines the recursive
and semi-symmetric information measures depending on a nonpositive parameter is stable in a certain sense. 相似文献
492.
493.
Gyula Károlyi 《Journal of Combinatorial Theory, Series A》2009,116(3):741-746
Let A≠B be nonempty subsets of the group of integers modulo a prime p. If p?|A|+|B|−2, then at least |A|+|B|−2 different residue classes can be represented as a+b, where a∈A, b∈B and a≠b. This result complements the solution of a problem of Erd?s and Heilbronn obtained by Alon, Nathanson, and Ruzsa. 相似文献
494.
Dr. Federico A. Rojas‐Quijano Dr. Gyula Tircsó Enikő Tircsóné Benyó Dr. Zsolt Baranyai Huan Tran Hoang Dr. Ferenc K. Kálmán Dr. Praveen K. Gulaka Prof. Vikram D. Kodibagkar Prof. Silvio Aime Prof. Zoltán Kovács Prof. A. Dean Sherry 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(31):9669-9676
Tissue hypoxia occurs in pathologic conditions, such as cancer, ischemic heart disease and stroke when oxygen demand is greater than oxygen supply. An imaging method that can differentiate hypoxic versus normoxic tissue could have an immediate impact on therapy choices. In this work, the gadolinium(III) complex of 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) with a 2‐nitroimidazole attached to one carboxyl group via an amide linkage was prepared, characterized and tested as a hypoxia‐sensitive MRI agent. A control complex, Gd(DO3A‐monobutylamide), was also prepared in order to test whether the nitroimidazole side‐chain alters either the water proton T1 relaxivity or the thermodynamic stability of the complex. The stabilities of these complexes were lower than that of Gd(DOTA)? as expected for mono‐amide derivatives. The water proton T1 relaxivity (r1), bound water residence lifetime (τM) and rotational correlation time (τR) of both complexes was determined by relaxivity measurements, variable temperature 17O NMR spectroscopy and proton nuclear magnetic relaxation dispersion (NMRD) studies. The resulting parameters (r1=6.38 mM ?1 s?1 at 20 MHz , τM=0.71 μs, τR=141 ps) determined for the nitroimidazole derivative closely parallel to those of other Gd(DO3A‐monoamide) complexes of similar molecular size. In vitro MR imaging experiments with 9L rat glioma cells maintained under nitrogen (hypoxic) versus oxygen (normoxic) gas showed that both agents enter cells but only the nitroimidazole derivative was trapped in cells maintained under N2 as evidenced by an approximately twofold decrease in T1 measured for hypoxic cells versus normoxic cells exposed to this agent. These results suggest that the nitroimidazole derivative might serve as a molecular reporter for discriminating hypoxic versus normoxic tissues by MRI. 相似文献
495.
Rojas-Quijano FA Tircsó G Tircsóné Benyó E Baranyai Z Tran Hoang H Kálmán FK Gulaka PK Kodibagkar VD Aime S Kovács Z Sherry AD 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(31):9669-9676
Tissue hypoxia occurs in pathologic conditions, such as cancer, ischemic heart disease and stroke when oxygen demand is greater than oxygen supply. An imaging method that can differentiate hypoxic versus normoxic tissue could have an immediate impact on therapy choices. In this work, the gadolinium(III) complex of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) with a 2-nitroimidazole attached to one carboxyl group via an amide linkage was prepared, characterized and tested as a hypoxia-sensitive MRI agent. A control complex, Gd(DO3A-monobutylamide), was also prepared in order to test whether the nitroimidazole side-chain alters either the water proton T(1) relaxivity or the thermodynamic stability of the complex. The stabilities of these complexes were lower than that of Gd(DOTA)(-) as expected for mono-amide derivatives. The water proton T(1) relaxivity (r(1)), bound water residence lifetime (τ(M)) and rotational correlation time (τ(R)) of both complexes was determined by relaxivity measurements, variable temperature (17) O?NMR spectroscopy and proton nuclear magnetic relaxation dispersion (NMRD) studies. The resulting parameters (r(1) =6.38?mM(-1) s(-1) at 20?MHz, τ(M) =0.71?μs, τ(R) =141?ps) determined for the nitroimidazole derivative closely parallel to those of other Gd(DO3A-monoamide) complexes of similar molecular size. In vitro MR imaging experiments with 9L rat glioma cells maintained under nitrogen (hypoxic) versus oxygen (normoxic) gas showed that both agents enter cells but only the nitroimidazole derivative was trapped in cells maintained under N(2) as evidenced by an approximately twofold decrease in T(1) measured for hypoxic cells versus normoxic cells exposed to this agent. These results suggest that the nitroimidazole derivative might serve as a molecular reporter for discriminating hypoxic versus normoxic tissues by MRI. 相似文献
496.
Influence of different bentonites on the rare earth element concentrations of clarified Romanian wines 总被引:4,自引:0,他引:4
The rare earth element (REE) concentrations of 19 Romanian young wine samples originating from the Dealurile Moldovei viticulture area were determined by double focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) after microwave-assisted digestion with nitric acid. The determination of Eu was hampered by the BaO molecular interference. Generally, the red wine samples were more concentrated for REEs than the white wine samples studied. The REE concentrations of the four bentonites (Gelbenton, Evergel, BW200, Tükrös) determined after their fusion were higher by three orders of magnitude than those of the wine samples. After a simulated wine purification process performed with these bentonite samples and a red and white pool samples, the REE concentrations of the clarified wine samples increased by 1.2–1.5 times for red, and 1.3–3 times for white wines in case of the fibrous bentonite sample (Gelbenton), by about 2–5 times in case of the bentonite containing ovalbumin, caseine and gelatine (Evergel), meanwhile this factor was about 20–25 for Na bentonite powder samples (BW200, Tükrös). On basis of the chemometric evaluation using the REE concentrations as input data, the majority of the Feteasca wines belonged to the same cluster as well as the two Cabernet Sauvignon to another subcluster. The adequate choice of the bentonite may allow the use of REEs as fingerprints for determining the wine provenance. 相似文献
497.
va Boros Ferenc Bertha Jzsef Fetter Gbor Czira Antal Feller Gyula Simig Mria Kajtr‐Peredy 《Journal of heterocyclic chemistry》2006,43(1):87-94
The reaction of 4‐mesyloxymethylazetidin‐2‐one derivatives 3 with ammonia and sodium methoxide was investigated. The two electrophilic centers of the substrate reactesuccessively, resulting in cleavage of the lactam bond and formation of a new aziridine ring. The resulting type 6 and 8 aziridinylacetic acid derivatives are related to the novel 2‐(aziridin‐2‐yl)‐3‐phenylpropionic acid type carboxypeptidase A inhibitors and, as such, potential drug candidates. 相似文献
498.
A properly passivated silicon surface is chemically stable, and all interface properties are constant. The freshly etched Si surface is full of dangling bonds resulting in high surface activity and instability. Hydrogen treatment is a proper procedure to decrease the number of dangling bonds. We demonstrated that deuterium adsorbs on Si surface at room temperature much stronger than hydrogen. Moreover, in case of deuterium-passivated wafers the vacuum storage can be omitted without risking the non-controlled native oxidation of silicon for up to 5 h or more. It could be a suitable and more robust surface cleaning and passivation process for the industry, but heavy water is expensive. As a cheaper procedure, we showed that 1 min vapor phase treatment at 65 °C of heavy water (D2O) + 50% HF (e.g. 20:1) mixture was enough to remove the native oxide and to passivate the Si surface without any degradation of the atomic surface flatness. The surface evolution of the D-passivated surface was followed by contact angle measurements, spectroscopic ellipsometry (SE), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), infrared absorption spectroscopy (IR), surface potential and surface photovoltage (SPV) mapping and light induced potential transient method. Qualification and the results were compared to the H-passivated, bare and native oxide covered Si surface. Our passivation test results confirmed that using D-passivation on Si surface is a promising method in the MOS technology and the interface engineering processes. 相似文献
499.
Jana Svobodová Martin Beneš Pavel Dubský Gyula Vigh Bohuslav Gaš 《Electrophoresis》2012,33(19-20):3012-3020
This paper describes the results of the second‐level testing of the simulation program Simul 5 Complex. We compare the published experimental results with the simulated migration behavior of the enantiomers at different pH and chiral selector concentration values and use the same optimization object function, separation selectivity, as the original papers. Simul 5 Complex proved to be a suitable tool for the prediction of the effective mobilities, separation selectivities, and migration order reversals in these pH‐dependent and CD concentration dependent enantiomer separations. In addition, by performing simulations of four different separations systems (both real and model systems), Simul 5 Complex revealed the existence of unexpected and hitherto unexplained electromigration dispersion effects that were caused by the complexation process itself and could significantly impair the quality of the separations. 相似文献
500.
A simple dynamical density functional theory is used to investigate freezing of an undercooled liquid in the presence of a crystalline substrate. We find that the adsorption of the crystalline phase on the substrate, the contact angle, and the height of the nucleation barrier are nonmonotonic functions of the lattice constant of the substrate. We show that the free-growth-limited model of particle-induced freezing by Greer et al. [Acta Mater. 48, 2823 (2000)] is valid for larger nanoparticles and a small anisotropy of the interface free energy. Faceting due to the small size of the foreign particle or a high anisotropy decouples free growth from the critical size of homogeneous nuclei. 相似文献