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81.
Derivatives of 2-chloro-2′-deoxyadenosine ( 1a ) containing secondary 6-NH2 groups ( 5a-c ) or a 8-Br substituent ( 9 ) were synthesized. They were tested together with ring-modified congeners containing a pyrrolo[2,3-b]pyridine, pyrrolo[3,2-c]pyridine, or pyrazolo[3,4-d]pyrimidine ring system as inhibitors of various leukemic cell lines. Only the 8-Br derivatives 9 showed inhibitory activity, whereas the base-modified congeners were not active. Compound 1a was protonated at a pKa = 1.4 (2′-deoxyadenosine at pKa = 3.8). Protonation occurred at N(7) and not at N(1) as observed for dA. 相似文献
82.
Dariusz Wyrzykowski Rafa Kruszyski Urszula Kucharska Zygmunt Warnke 《无机化学与普通化学杂志》2006,632(4):624-628
A series of tetrahalogenoferrates(III), [FeBr4?nCln]? (n=0‐4) stabilized with the tetrabutylammonium cation, of general formula [(C4H9)4N][FeBr4?nCln], has been synthesized. The crystal and molecular structure of [(C4H9)4N][FeCl4] was determined. The iron cation adopts slightly distorted tetrahedral coordination with two opposite angles smaller than tetrahedral one, two equal to tetrahedral and two larger than tetrahedral. The bond valences were computed. The total valence of iron atom is equal to 3.08. In the structure can be found only one hydrogen bond C(1)–H···Cl. Except mentioned there are no unusually intermolecular short contacts between ions existing in the structure. All [(C4H9)4N][FeBr4?nCln] (n=0‐4) compounds are isostructural in solid state. On the basis of conductometric measurements, relative stabilities of the anions have been estimated in methanol (MeOH), dimethyl sulfoxide (DMSO), acetone (AC), acetonitrile (AN) and dichloromethane (CH2Cl2) representing both polar (including amphiprotic and aprotic) as well as non‐polar solvents. Further, the dissociation constants of the compounds were calculated from the expanded Pitt's conductivity equation. The results of the conductometric measurements were supported by electronic spectra. 相似文献
83.
Joseph R. Lakowicz Henryk Szmacinski Ignacy Gryczynski 《Photochemistry and photobiology》1988,47(1):31-41
Abstract— We used frequency-domain fluorescence spectroscopy to measure rotational diffusion and time-resolved emission spectra of indole in methanol on the picosecond timescale. The indole emission was quenched by acrylamide to allow measurements to the instrumental limit of 2 GHz and to eliminate emission from the longer-lived indole molecules, which can no longer provide information on the picosecond (ps) processes. The resolution was adequate to measure rotational correlation times as short as 8 ps at 80†C, and spectral relaxation times as short as 16 ps at 5†C. 相似文献
84.
Hanna Małuszyńska Władysław Boczoń Zygmunt Kałuski 《Journal of chemical crystallography》1986,16(5):687-694
The formula of the title compound is C22H30N2,M
T
=322.5; monoclinic:P21,a=7.569(3),b=9.381(1),c=13.684(4) Å,=105.81(2)°,Z=2,V
c
=933.7 Å3,D
x
=1.15 g cm–3,(CuK)=5.1 cm–1. The sparteine skeleton (bis-quinolizidine system) has atrans-trans configuration. RingA has an intermediate form between the sofa and half-chair conformations, ringsB andD-chair, and ringC-boat conformations, respectively. The double bond C(2)=C(3) is equal to 1.343(9) Å. The phenyl ring is planar and makes an angle with a plane through N(1), C(2), C(3), and C(4) atoms equal to 43.9°. 相似文献
85.
Sabato D'Auria Paolo Bazzicalupo Mosé Rossi Ignacy Gryczynski Joseph R. Lakowicz 《Journal of fluorescence》2000,10(1):27-34
ASCUT-1 is a protein found in cuticlin, the insoluble residue of the cuticles of the nematode Ascaris lumbricoides. It contains the CUT-1-like domain which is shared by members of a novel family of components of extracellular matrices. The monomeric form of ASCUT-1 contains a single tryptophan residue. An understanding of the structure-function relationship of the protein under different chemical-physical conditions is of fundamental importance for an understanding of its structure and function in cuticles. In this paper we report the effect of the temperature and sodium dodecyl sulfate on the structural stability of this protein. The structure of the protein was studied in the temperature range 25–85°C in the absence and in the presence of sodium dodecyl sulfate by frequency-domain measurements of the intrinsic fluorescence intensity and anisotropy decays. The time-resolved fluorescence data in the absence of SDS indicated that the tryptophanyl emission decays were well described by a bimodal lifetime distribution, and that the temperature increases resulted in the sharpening and in the shortening of the tryptophanyl lifetime distribution. In the presence of SDS an unimodal fluorescence lifetime distribution as well as a marked decrease in the anisotropy decay values were observed. 相似文献
86.
Marta Dudek Lidia Wolska Michae Pilarczyk Bogdan Zygmunt Jacek Namienik 《Journal of separation science》2000,23(6):449-454
The possibility of using a piece of gas chromatographic capillary column as a tubular denuder for isolation and enrichment of organic pollutants present in air was studied. The partition coefficients (Kfs) of typical organic pollutants (benzene, chlorobenzene, toluene) between the gaseous phase and the denuder sorption layer were determined and effects of analyte concentration in the gaseous phase and gas flow rate on partitioning were studied. The partition coefficients were found to be constant in the studied range of concentration and gaseous mixture flow rate. A piece of a capillary column coated with polydimethylosiloxane can be used as a tubular denuder. 相似文献
87.
Emilia Stycze Agnieszka Pattek-Janczyk Maria Gazda Wojciech K. J
wiak Dariusz Wyrzykowski Zygmunt Warnke 《Thermochimica Acta》2008,480(1-2):30-34
Thermal decomposition of bis(tetraethylammonium) tetrachloroferrate(II) has been studied using the TG-FTIR, TG–MS and DTA techniques. The measurements were carried out in an inert atmosphere over the temperature range of 293–1073 K. The solid products of the thermal decomposition were identified by the FT-FIR, Mössbauer spectroscopy as well as the X-ray powder diffractometry. The influence of the oxidation state and the nature of a metal on thermal transformation profiles of analogous complexes have been discussed. 相似文献
88.
Andrzej Katrusiak Zygmunt Kałuski Paweł Pietrzak Jerzy Skolik 《Journal of chemical crystallography》1986,16(2):191-206
1(6)-Dehydrosparteinium monoperchlorate, [C15H25N2]+·ClO
4
–
, is orthorhombicP212121,a=12.473(2),b=24.292(3),c=10.835(1) Å,V
c
=3353.7(9) Å3,Z=8,D
x
=1.32,D
m
=1.32 g cm–3, (CuK)=20.7 cm–1. The finalR was 0.097 for 2091 observed counter reflections. A partial disorder of the crystal structure has been observed. The two independent perchlorate anions are orientationally disordered, and the peripheral atoms in the cation skeletons have large temperature factors due both to conformational disorder of ringsA and to disordered orientations of the whole cations alike. In ringsA, atoms C(3) and C(4), trans-annular to the immonium bond, are disordered to a different extent in each of the two independent cations. RingsB,C, andD have sofa (distorted towards half-chair), chair, and chair conformations, respectively. The quinolizidinium and quinolizidine moieties have planar and cis configurations, respectively. The title compound was obtained from 5-dehydrosparteine, the product of mercuric acetate dehydrogenation of sparteine at room temperature. From13C NMR measurements in2H2O and in DMSO-2H6 it is evident that, in solution, the molecular geometry with chair/chair cis-ring fusion within the quinolizidine moiety is present, as was found in the crystalline state by X-ray analysis. 相似文献
89.
Zygmunt J. Jakubek S.G. Nakhate Benoit SimardWalter J. Balfour 《Journal of Molecular Spectroscopy》2002,211(1):135-146
The yttrium monohydride spectrum in the range 12 500-25 000 cm−1 has been studied by various laser-induced fluorescence (LIF) techniques. YH (YD) molecules have been produced in a free jet molecular beam apparatus by a laser vaporizing yttrium metal in the presence of He doped with H2 (D2) or NH3 (ND3). Low-resolution (∼0.04 cm−1) excitation spectra have been recorded in the entire studied range. Four green bands (19 300-19 900 cm−1) of the YH isotopomer have been studied in more detail: (1) high-resolution (∼120 MHz, ∼0.004 cm−1) excitation spectra have been recorded, (2) dispersed fluorescence spectra have been obtained, and (3) lifetimes of the selected rotational levels of the upper states have been measured. Our observations have confirmed that the ground state of yttrium monohydride has 1Σ+ symmetry and have provided a link between the singlet and triplet manifolds. The upper states of the observed transitions have been tentatively assigned to five electronic states, d0+, f3Π, f′1, D1Π, E0+, and Fl. The low-energy excited electronic state observed in the dispersed fluorescence experiment has been assigned as the a3Δ state. 相似文献
90.
Grzegorz Piszczek Badri P. Maliwal Ignacy Gryczynski Jonathan Dattelbaum Joseph R. Lakowicz 《Journal of fluorescence》2001,11(2):101-107
We describe multiphoton excitation of the lanthanides europium (Eu3+) and terbium (Tb3+) when these ions are complexed with nucleic acids, proteins, and fluorescent chelators. In all cases excitation occurs by multiphoton absorption of the sensitizers. For the nucleotide GDP and an oligonucleotide with several guanines, the sensitized emission of Tb3+ excited at 776 nm indicated a three-photon process. For Tb3+ bound to the wild-type troponin C and a single tryptophan mutant (26W), excitation at 794 nm was also close to a three-photon process. For lanthanide chelators containing various sensitizers, we observed three-photon excitation in the case of methyl anthranilate, a mixuture of two- and three-photon excitation for carbostyril 124, and a two-photon process with a coumarin derivative. In the case of coumarin-sensitized emission of Eu3+ varied from a two- to a three-photon process at wavelengths ranging from 780 to 880 nm. The sensitized luminescence also shows significantly higher photostability compared to the fluorescence from the organic fluorophores alone. These results suggest the use of multiphoton-induced sensitized lanthanide fluorescence in biochemistry and cellular imaging.On leave from the Institute of Experimental Physics 相似文献