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101.
102.
Fluorescence amplification by electrochemically deposited silver nanowires with fractal architecture
Goldys EM Drozdowicz-Tomsia K Xie F Shtoyko T Matveeva E Gryczynski I Gryczynski Z 《Journal of the American Chemical Society》2007,129(40):12117-12122
Electrochemically deposited silver structures with nanowires 50-100 nm in diameter show high fluorescence amplification and strongly reduced fluorescence lifetimes. Both quantities depend on the structure thickness. With increasing thickness the fluorescence amplification proportionally increases and the fluorescence lifetime decreases. This thickness dependence is caused by fluorophore interaction with a system of plasmon excitations in coupled nanowires extending over micrometer size regions. Thus the amplification is attributed to a combination of extended structure area and strong plasmonic coupling between nanowires which also help to radiatively scatter the fluorescence emission. 相似文献
103.
The relative importance of local and long range interactions in the characteristics of the protein folding process has long been a matter of controversy. Computer simulations based on Gō-type models have been widely used to study this topic, but without much agreement on which type of interactions is more relevant for the foldability of a protein. In this work, the authors also employ a topology-based potential and simulation model to analyze the influence of local and long range interactions on the thermodynamics of the folding transition. The former are mainly used to control the degree of flexibility (or stiffness) of the chain, mostly appreciable in the unfolded (noncompact) state. Our results show the different effects that local and nonlocal interactions have on the entropy and the energy of the system. This implies that a balance between both types of interactions is required, so that a free energy barrier exists between the native and the denatured states. The variations in the contribution of both types of interactions have also a direct effect on the stability of the chain conformations, including the possible appearance of thermodynamic folding intermediates. 相似文献
104.
105.
Investigation of adsorption and vertical migration of137Cs in three kinds of soil at Lublin vicinity
S. Chibowski J. Zygmunt Z. Klimowicz 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):287-295
The results of field, column and laboratory studies carried out on three types of mineral soils are encloses presented. Based
on the field tests, average migration rates of137Cs were calculated. The highest rate was found for the brown soil (FAO/UNESCO—Cambisol). Cesium migrated with the lowest rate
in the podzol soil (FAO/UNESCO—Cambic Podzol). The column experiments confirmed the above observation. In laboratory tests
the adsorption and desorption isotherms of Cs were determined on samples taken from 0–2 cm layers of each soil profile. It
was found from the calculated partition coefficients that Cs is always irreversibly bonded to some extent, but it appears
to be completely and irreversibly immobilized on the podzol soil. The permanent retention of cesium in the podzol soil was
also confirmed by microcalorimetric studies. The desorption energy was negligibly small and amounted to −0.21 mJ/g. In the
brown soil, containing prevailing amounts of loamy minerals, the desorption energy was found to be 106.89 mJ/g. The investigations
are supplemented by the sorption kinetics measurements. These indicate that the adsorption equilibrium is reached after a
dozen, up to twenty or so minutes. 相似文献
106.
Danuta Gorlo Bogdan Zygmunt Marta Dudek Anna Jaszek Michał Pilarczyk J. Namieśnik 《Analytical and bioanalytical chemistry》1999,363(7):696-699
Practical application of Solid-Phase Microextraction (SPME) for the assessment of the quality of indoor air is presented.
SPME was used to sample selected organic pollutants (carbon tetrachloride, benzene, toluene, chlorobenzene, p-xylene and n-decane). An SPME fiber was coated with a 100 μm film of polydimethylsiloxane. The analytes extracted were analysed with a
gas chromatograph directly coupled with a mass spectrometer (GC-MS). The method was used to assess the indoor air quality
in a few selected flats. The concentrations ranged from below detection limits to 6.9 mg/m3 for benzene depending on the flat; they were relatively high for newly built or freshly renovated flats.
Received: 14 July 1998 / Revised: 17 November 1998 / Accepted: 21 November 1998 相似文献
107.
Zygmunt Bak 《Czechoslovak Journal of Physics》1999,49(11):1525-1529
Within an analytical approach we study the RKKY interaction mediated by the electron gas, which shows fractional spectral
dimensionality. We derive formula for the RKKY exchange integral in a system of nonintegral dimensionality. Also the modifications
of magnetic interaction and magnetic moments in metallic overlayers due to the surface/interface effects are considered.
Presented at the VIII-th Symposium on Surface Physics, Třešt’ Castle, Czech Republic, June 28 – July 2, 1999. 相似文献
108.
Lidia Moreira Lima Tiago Fernandes da Silva Carlos Eduardo da Silva Monteiro Cristiane Aparecida-Silva Walfrido Bispo Júnior Aline Cavalcanti de Queiroz Magna Suzana Alexandre-Moreira Gisele Zapata-Sudo Eliezer J. Barreiro 《Molecules (Basel, Switzerland)》2021,26(16)
Acylhydrazones are still an important framework to the design of new bioactive compounds. As treatment of chronic pain represents a clinical challenge, we decided to modify the structure of LASSBio-1514 (1), previously described as anti-inflammatory and analgesic prototype. Applying the homologation as a strategy for molecular modification, we designed a series of cyclopentyl- (2a–e), cyclobutyl- (3a–e), and cyclopropylacylhydrazones (4a–e) that were synthetized and evaluated in murine models of inflammation and pain. A comparison of their in silico physicochemical and drug-like profile was conducted, as well as their anti-inflammatory and analgesic effect. Compounds 4a (LASSBio-1755) and 4e (LASSBio-1757) displayed excellent in silico drug-like profiles and were identified as new analgesic lead-candidates in acute and chronic model of pain, through oral administration. 相似文献
109.
The role of water’s H-bond percolation network in acid-assisted proton transfer was studied in water and glycerol solutions
and in sugar glasses. Proton transfer rates were determined by the fluorescence of pyrene-1-carboxylate, a compound with a
higher pK in its excited state relative to the ground state. Excitation of pyrene-1-COO− produces fluorescence from pyrene-1-COOH when a proton is accepted during the excited singlet state lifetime of pyrene-1-COO−. The presence of glycerol as an aqueous cosolvent decreases proton transfer rates from phosphoric and acetic acid in a manner
that does not follow the Stokes relationship on viscosity. In sugar glass composed of trehalose and sucrose, proton transfer
occurs when phosphate is incorporated in the glass. Sugar glass containing phosphate retains water and it is suggested that
proton transfer requires this water. The infrared (IR) frequency of water bending mode in sugar glass and in aqueous solution
is affected by the presence of phosphate and the IR spectral bands of all phosphate species in water are temperature dependent;
both results are consistent with H-bonding between water and phosphate. The fluorescence results, which studied the effect
of cosolvent, highlight the role of water in assisting proton transfer in reactions involving biological acids, and the IR
results, which give spectroscopic evidence for H-bonding between water and phosphate, are consistent with a mechanism of proton
transfer involving H-bonding. The possibility that the phosphate-rich surface of membranes assists in proton equilibration
in cells is discussed. 相似文献
110.
Zdenko asar Ivan Leban Alenka Majcen-le Marechal Lidia Piekara-Sady Dominique Lorcy 《Comptes Rendus Chimie》2009,12(9):1057-1065
The synthesis and the redox behaviour of electroactive donor molecules incorporating an azino spacer group between a benzoselenazole core and another heterocyclic moiety, either a benzoselenazole one or a thiazole one, are reported. Neutral complexes were obtained with TCNQ and, for the first time with dithiadiazafulvalene or diselenadiazafulvalene derivatives, cation radical salts by electrocrystallization. Crystal structures data of these complexes are presented and their geometries compared with those deduced from theoretical calculations. 相似文献