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991.
Adekenov Sergazy M. Zhanimkhanova Pernesh Zh. Nurmaganbetov Zhangeldy S. Amanzhan Asel Chernov Sergey V. Turmukhambetov Aibek Zh. Bagryanskaya Irina Yu. Gatilov Yurii V. Shults Elvira E. 《Chemistry of Heterocyclic Compounds》2019,55(2):135-141
Chemistry of Heterocyclic Compounds - Hybrid molecules containing β-carboline and 1-acetylpyrazoline moieties were obtained on the basis of the alkaloid harmine. The synthetic procedure... 相似文献
992.
Andrey V. Yudintsev Natalia Yu. Shilyagina Darya V. Dyakova Svetlana A. Lermontova Larisa G. Klapshina Evgeniy L. Guryev Irina V. Balalaeva Vladimir A. Vodeneev 《Journal of fluorescence》2018,28(2):513-522
Tetra(aryl)tetracyanoporphyrazines are the promising group of dyes for photodynamic therapy of tumors with unique combination of photosensitizer properties and sensitivity of fluorescence parameters to the environment viscosity. However, in vivo application of such hydrophobic photosensitizers requires using of drug carriers ensuring efficient delivery to the tumor site. The present study is focused on obtaining liposomes loaded with tetrakis(4-benzyloxyphenyl)tetracyanoporphyrazine and examining their properties depending on lipid composition. An efficient loading of the dye and a high long-term stability were proved for the liposomes composed of phosphatidylcholine with cholesterol and phosphatidylglycerol. This can be explained by the presence of negatively charged lipids in the bilayer and, as a consequence, a high value of the surface potential. A high rate of cellular uptake and a strong photoinduced toxicity give the prerequisites for the further use of the liposomal form of the photosensitizer for photodynamic therapy of tumors. 相似文献
993.
Dichloromethane as solvent and reagent: a case study of photoinduced reactions in mixed phosphonium‐iodonium ylide 下载免费PDF全文
Irina I. Levina Olga N. Klimovich Dmitrii S. Vinogradov Tatyana A. Podrugina Denis S. Bormotov Alexey S. Kononikhin Olga V. Dement'eva Ivan N. Senchikhin Evgeny N. Nikolaev Vladimir A. Kuzmin Tatiana D. Nekipelova 《Journal of Physical Organic Chemistry》2018,31(7)
Several years ago the photoinduced reaction of mixed phosphonium‐iodonium ylides ( 1 ) with acetylenes ( 2 ) to give λ5‐phosphinolines ( 3 ) and substituted furans ( 4 ) was described. This reaction is one‐pot, metal‐free synthesis of heterocycles 3 and 4 with the yields of 40% to 80%. The reaction proceeds only in dichloromethane (DCM) at the high ylide concentrations (>0.01 mol/L). The product analysis by 31P NMR, electrospray ionization mass spectrometry, UV‐vis spectrophotometry, and the dynamic light scattering study of the self‐aggregation of the ylide in DCM showed a dual role of the solvent in the photoinduced reactions of mixed phosphonium‐iodonium ylide: (i) at the low ylide concentrations (<0.01 mol/L), the conjugated photoinitiation of the chain reaction in DCM results in the formation of chlorine‐containing products and (ii) at the high ylide concentrations (>0.01 mol/L), the photolysis mechanism is determined by self‐organization of the ylide molecules to give large stable aggregates in DCM, in which the target heterocycles are synthesized. Two important issues follow from the study. First, the annulation reaction between mixed phosphonium‐iodonium ylide and acetylenes occurs only when the reactive intermediates are in close proximity to one other, and, second, DCM is not inert reagent in reactions occurring with participation of radicals and in one form or another can participate in photoinduced radical reactions of various solutes. 相似文献
994.
Electrochemical reduction of 2,4‐dimethyl(diethyl)‐9‐oxo‐10‐(4‐heptoxyphenyl)‐9H‐thioxanthenium hexafluorophosphates and 2,4‐dimethyl(diethyl)‐9H‐thioxanthene‐9‐ones 下载免费PDF全文
Leonid A. Shundrin Pavel A. Avrorov Irina G. Irtegova Danila S. Odintsov Alexander F. Poveshchenko 《Journal of Physical Organic Chemistry》2018,31(9)
Electrochemical reduction of 2,4‐dimethyl(diethyl)‐9‐oxo‐10‐(4‐heptoxyphenyl)‐9H‐thioxanthenium hexafluorophosphates in acetonitrile (MeCN) and N,N‐dimethylformamide is an irreversible 1‐electron process accompanied by the cleavage of the C(Ph)‐S bond in thioxanthenium cations with the formation of the corresponding 2,4‐dimethyl(diethyl)‐9H‐thioxanthene‐9‐ones. One‐electron reversible electrochemical reduction of the latter compounds occurs at more negative potentials and yields the corresponding radical anions, which have been characterized by electron paramagnetic resonance spectroscopy and density functional theory calculations at the (U)B3LYP/6‐31+G*/polarizable continuum model level of theory. 相似文献
995.
Ferenc Somodi Irina Borbáth József L. Margitfalvi Sándor Stichleutner Károly Lázár 《Hyperfine Interactions》2009,192(1-3):13-21
The active catalytic components in tin oxide containing alumina-supported gold catalyst were examined by comparing and analysing the in situ Mössbauer spectra of the SnO x –Al2O3 support and the 3 wt.% Au/SnO x –Al2O3 catalyst (1.1 wt.% Sn, Au/Sn = 3:2 atomic ratio). Samples were prepared by using organometallic precursor of 119SnMe4 (enriched). First tin was grafted to the alumina surface from the organometallic precursor compound. In the next step the grafted complexes were decomposed in flowing oxygen. Gold was deposited onto the SnO x –Al2O3 support in the subsequent step. Analysis of in situ spectra shows that in Au/SnO x –Al2O3 catalyst after activation in hydrogen at 620 K tin may occur in three different oxidation states [Sn (IV), Sn(II) and Sn(0)] simultaneously. The metallic tin is a component of the bimetallic AuSn alloy phase. Data presented provide the first evidence for the formation of alloy-type supported Sn–Au catalyst on alumina. Furthermore, from the spectra recorded at different temperatures, values of the Debye temperatures and recoilless fractions were also determined for the various species. The results show that in catalytic oxidation of carbon monoxide at room temperature the dominant part of Sn(II) and the AuSn alloy is oxidized. 相似文献
996.
Irina Koshelev Rong Huang Timothy Graber Mati Meron J. Lewis Muir William Lavender Kevin Battaile Anne M. Mulichak Lisa J. Keefe 《Journal of synchrotron radiation》2009,16(5):647-657
The IMCA‐CAT bending‐magnet beamline was upgraded with a collimating mirror in order to achieve the energy resolution required to conduct high‐quality multi‐ and single‐wavelength anomalous diffraction (MAD/SAD) experiments without sacrificing beamline flux throughput. Following the upgrade, the bending‐magnet beamline achieves a flux of 8 × 1011 photons s?1 at 1 Å wavelength, at a beamline aperture of 1.5 mrad (horizontal) × 86 µrad (vertical), with energy resolution (limited mostly by the intrinsic resolution of the monochromator optics) δE/E = 1.5 × 10?4 (at 10 kV). The beamline operates in a dynamic range of 7.5–17.5 keV and delivers to the sample focused beam of size (FWHM) 240 µm (horizontally) × 160 µm (vertically). The performance of the 17‐BM beamline optics and its deviation from ideally shaped optics is evaluated in the context of the requirements imposed by the needs of protein crystallography experiments. An assessment of flux losses is given in relation to the (geometric) properties of major beamline components. 相似文献
997.
Yuriy G. Kolyagin Irina I. Ivanova Yuri A. Pirogov 《Solid state nuclear magnetic resonance》2009,35(2):104-112
The early stages of methane, ethane and propane conversion were studied by in situ 1H and 13C MAS NMR techniques over fully exchanged Zn2+/MFI catalyst obtained by the reaction with zinc vapour. The in situ techniques revealed strong interaction of alkanes with Zn2+ cations evidenced by significant shift of the corresponding NMR lines. Besides that, the formation of methyl zinc, ethyl zinc and n-propyl zinc species along with bridging and silanol surface OH-groups was detected already at the ambient temperature. These results pointed to dissociative adsorption of alkanes over (ZO)–Zn2+–(OZ) and (ZO)–Zn2+–(OSi) active sites of the catalyst. The dissociative adsorption was shown to be a dead-end surface reaction in the case of methane starting reactant, while in the case of ethane and propane, it appeared to be responsible for the initiation of the catalytic cycle leading to alkenes and dihydrogen formation and regeneration of zinc containing catalytic sites. 相似文献
998.
Alexandr V. Piskunov Irina N. Mescheryakova Georgii K. Fukin Artyem S. Bogomyakov Galina V. Romanenko Vladimir K. Cherkasov Gleb A. Abakumov 《Heteroatom Chemistry》2009,20(6):332-340
The reduction of 4,6‐di‐tert‐butyl‐N‐(2, 6‐di‐iso‐propylphenyl)‐o‐iminobenzoquinone (imQ) by tin amalgam in hexane solution leads to new six‐coordinated o‐iminoquinonato tin(IV) complex (iSQ)2SnAP ( 1 ) (where iSQ and AP are o‐iminosemiquinolate and dianion o‐amidophenolate, respectively). Variable temperature magnetic susceptibility measurements of 1 have shown that this complex possesses a weak ferromagnetic exchange between o‐iminosemiquinonate ligands. The oxidation of 1 with air oxygen produces new o‐iminoquinonolate tin(IV) derivatives [(iSQ)Sn(AP)]2O ( 2 ) and (iSQ)2Sn(OH)2 ( 3 ) containing μ‐oxo‐ and hydroxo‐ligands, respectively. The electronic structure of 1 was examined by DFT analysis. Complexes 1–3 have been investigated using single‐crystal X‐ray diffraction. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:332–340, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20555 相似文献
999.
Supercontinua generated in highly nonlinear fibers by ultrashort-pulse lasers can be used for high-resolution Fourier transform absorption spectroscopy. The practical advantages of these bright ultrabroadband light sources for spectroscopy in the near-infrared region are reported. A Cr(4+):YAG femtosecond laser broadened by an extruded soft-glass photonic crystal fiber, emitting from 1200 to 2200 nm and from 675 to 950 nm, provides a spectral radiance 1 x 10(5) times higher than that of a 3000 K blackbody and 10(2) times higher than that of synchrotron radiation. The C(2)H(2) and NH(3) overtone spectra are recorded by using this source within a few seconds. 相似文献
1000.
Irina S. Zemel Joseph P. Corrigan Arthur E. Woodward 《Journal of Polymer Science.Polymer Physics》1989,27(12):2479-2492
The crystallization of segmented block copolymers of trans-1,4-polyisoprene (TPI)/expoxidized TPI from solution was investigated. One preparation with an average TPI block length of 14.5 and an average epoxidized TPI block length of 10 was crystallized from 2-pentanol at 20°C, 2-octanol at 20°C, and 2-pentanone at 0°C. A second preparation with an average TPI block length of 18 and the same average epoxidized TPI block length was crystallized from 2-octanol at 20°C and 2-pentanone at 0°C. The crystallization products were expoxidized in suspension a second time and then characterized by carbon-13 solution NMR to determine the average noncrystalline traverse length and the average crystalline stem length. The crystallized products were also studied by scanning electron microscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry to determine the morphology, the crystal form and crystallinity, and the melting point, respectively. The average noncrystalline traverse length was found to be highly dependent on the crystallization conditions and the crystalline stem length of the parent TPI lamellas; the composition of these traverses is discussed. 相似文献