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71.
Zygmunt Pogorzały 《Central European Journal of Mathematics》2014,12(6):813-823
In this note we show that there are a lot of orbit algebras that are invariant under stable equivalences of Morita type between self-injective algebras. There are also indicated some links between Auslander-Reiten periodicity of bimodules and noetherianity of their orbit algebras. 相似文献
72.
Badral Gansukh Qiuyue Zhang Zygmunt Flisak Tongling Liang Yanping Ma Wen-Hua Sun 《应用有机金属化学》2020,34(4):e5471
The five unsymmetrical 2-[1-(2,4-dibenzhydryl-6-chlorophenylimino)ethyl]-6-[1-(arylimino)ethyl]pyridine compounds (aryl: 2,6-Me2Ph L1 , 2,6-Et2Ph L2 , 2,6-iPr2Ph L3 , 2,4,6-Me3Ph L4 and 2,6-Et2–4-MePh L5 ) were prepared and characterized with FT-IR and 1H/13C NMR spectroscopy as well as elemental analysis. The treatment of L1 – L5 with CrCl3·3THF affords the corresponding chromium chloride complexes ( Cr1 – Cr5 ) in excellent yields. The molecular structures of Cr2 and Cr3 characterized by X-ray diffraction show a distorted octahedral geometry with three nitrogen atoms and three chlorine atoms around the metal center. On activation with either MAO or MMAO, Cr1 – Cr5 collectively display high activity (up to 14.96 × 106 g (PE) mol−1 (Cr) h−1 at 60 °C) affording highly linear polyethylene with low molecular weight distribution (Mw/Mn) ranging from 1.06 to 2.81. An in-depth catalytic evaluation of Cr1 was conducted in order to investigate how the cocatalyst type and its amount, reaction temperature and polymerization time affect the catalytic activities and polymer properties. 相似文献
73.
Nicole A. Rice William J. Bodnaryk Isaac Tamblyn Zygmunt J. Jakubek Jacques Lefebvre Greg Lopinski Alex Adronov Christa M. Homenick 《Journal of polymer science. Part A, Polymer chemistry》2020,58(13):1889-1902
To fully actualize the potential of boron nitride nanotubes (BNNTs), it is necessary to overcome the inherent insolubility of this nanomaterial. Drawing on the successes realized in the analogous carbon nanotube field, noncovalent functionalization with conjugated polymers offers a simple, scalable route toward the production of stable dispersions of BNNTs. 2,7-carbazoles were chosen as our core monomer based on density functional theory (DFT) predictions, which suggest superior interactions with BNNTs when compared to fluorene-BNNT interactions. Homo poly(2,7-carbazole)s and copolymers with fluorenes were synthesized and used successfully to disperse BNNTs into organic solvents. Thermogravimetric analysis and atomic force microscopy results confirm the proficiency of these polymers to disperse large amounts (> 80% by weight) of individualized BNNTs. Analysis of absorbance data shows that the choice of solvent is critical, with stability enhanced in THF compared to CHCl3 due to the more efficient planarization of polymer chains on the surface of BNNTs, particularly for the homopolymers. The utility of these highly-soluble poly(2,7-carbazole)-BNNT complexes for printed electronics and transparent composites was demonstrated by the fabrication of simple capacitors and incorporation into poly(methyl methacrylate) composites, respectively. 相似文献
74.
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
75.
In this study, a procedure was developed to determine short-chain alkane monocarboxylic acids (SCMAs) in aqueous samples using
headspace solid-phase microextraction (HS-SPME) followed by gas chromatography (GC) coupled with mass spectrometry (MS). A
Stabilwax-DA capillary column (30 m × 0.32-mm inner diameter, 0.50-μm film thickness) was used for GC separation and a 60-μm
poly(ethylene glycol) fiber was used to isolate SCMAs from water and introduce them into the gas chromatograph. Parameters
of HS-SPME, analyte desorption, and GC-MS analysis were selected and an analytical procedure was proposed. Limits of quantitation
were on the order of about 0.2 mg L-1. As an example of the application of the procedure, SCAMs were determined in municipal wastewater at different steps of treatment. 相似文献
76.
Zygmunt Bak 《Czechoslovak Journal of Physics》1999,49(11):1514-1514
Table of Contents
Contents of the proceedings 相似文献77.
Joseph R. Lakowicz Ignacy Gryczynski Wieslaw Wiczk Michael L. Johnson 《Journal of fluorescence》1994,4(2):169-177
Frequency-domain measurements of the intensity decays of melittin were used to recover the distribution of decay times displayed by its single tryptophan residue. Melittin was examined in the monomeric random coil state (water), in the monomeric -helical state (water-methanol), in the tetrameric state, and with 6M guanidine hydrochloride. In the presence of denaturant, where melittin is expected to be devoid of secondary structure, we observed a narrow distribution of lifetimes, similar to a double-exponential decay. In water the intensity decay of melittin was found to be described better by the distribution of decay times, which became progressively wider as the amount of -helix was increased by the methanol cosolvent or upon formation of the -helical tetrameric state. We also examined the intensity decays of melittin when complexed with calmodulin, troponin C, or lipid vesicles of 1-palmitoyl-2-oleyl-l--phosphatidylcholine (POPC). The lifetime distributions of the complexes with lipid were comparable to those observed in methanol-water, suggesting a similarity of the structure and/or dynamics of the environment surrounding the tryptophan residue. A broad lifetime distribution was observed for the melittin-calmodulin complex, suggesting a rigid structure and/or heterogeneity in the form of the complex. The lifetime distribution of the melittin-troponin C complex was more narrow, suggesting a more uniform structure, at least in the region surrounding the tryptophan residue. These results demonstrate that the lifetime distributions of a single tryptophan protein can be a sensitive indicator of the conformational heterogeneity and dynamics of proteins. 相似文献
78.
Two series of yttrium aluminum garnets doped with erbium and ytterbium ions have been studied by single-crystal X-ray diffraction. The single crystals were obtained by the Czochralski method. The concentration of doping ions was established by the plasma emission spectroscopy method. For the Er series, it is equal to 23.4, 46.7, 72.5, and 100%, whereas, for Yb-doped YAGs, it equals 26.5, 48.2, 75.9, and 100%. The results are supplemented by the data obtained for pure YAG. The X-ray data for all samples were collected at two temperatures: 295(2) and 102(2) K. Additionally, for YAGs doped with ca. 50% of doping ions, some more detailed temperature measurements were performed. Pure single crystals of ErAG and YbAG were also studied as a function of diffraction angles. Careful single-crystal measurements utilizing a CCD diffractometer revealed the unit cell parameters, which slightly-but significantly-deviate from cubic symmetry. The average unit cell parameters change linearly with the amount of substituting Er and Yb cations, with two different slopes related to the ionic radii. Both of the dodecahedral distances depend linearly on the concentration of the substituting ions, but the longer dodecahedral distance also changes with temperature contrary to the shorter one. There is no correlation between the octahedral interatomic distance [Al(VI)...O] and the unit cell parameter or temperature; however, weak trends appear for the tetrahedral [Al(IV)...O] distance. Such weak trends are just the secondary consequences of the ion substitution taking place at the dodecahedral site. The dependences between the unit cell parameters and the concentration of doping ions allow us to establish concentrations of particular doping ions in mixed (Er, Yb) doped YAGs just on the basis of the measured unit cell parameters and knowledge of the amount of Y. 相似文献
79.
Józef Kowalski Zygmunt Lasocki Colin Eaborn David R.M. Walton 《Journal of organometallic chemistry》1978,146(2):121-123
The previously reported unusual course of the reactions of the compounds MeCON(SiMe2CH2X)2 (X = Cl or Br) with methanol or water is suggested to involve neighbouring group participation. 相似文献
80.
The selection, collection, and preliminary treatment of plant material samples are discussed. Stages of sample preparation and extraction techniques presently used are described, and the most recent examples of sample preparation for chromatographic analysis are reviewed. Recent applications of gas chromatography for the assessment of emission of volatile organic compounds by plants are also described. 相似文献