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481.
Yuriy Azhniuk Vasyl Lopushansky Stepan Hasynets Volodymyr Kryshenik Alexander V. Gomonnai Dietrich R. T. Zahn 《Journal of Raman spectroscopy : JRS》2024,55(5):637-649
Raman spectra of (As1–xBix)2S3 glass samples with x ≤ 0.2 measured at the excitation with above-bandgap (532 nm) laser light at a relatively low power density (Pexc = 4 kW/cm2) clearly confirm the amorphous character, thereby markedly extending the known compositional interval of existence of the (As1–xBix)2S3 glass previously known (x ≤ 0.06). Spectra measured at an increased Pexc (40 kW/cm2) reveal a photostructural transformation in the illuminated area of the glass leading to an additional contribution of Bi–S bonds as well as to an increasing number of cage-type As4S4 units with homopolar As–As bonds. A number of new features in a broad range up to about 1,000 cm−1, which emerge in the Raman spectra of the (As1–xBix)2S3 glasses with high (x ≥ 0.14) Bi content and increase in intensity with the exposure time, are related to a photochemical transformation, namely, oxidation of arsenic and sulphur on the (As1–xBix)2S3 glass surface with formation of units containing arsenate AsO43− and sulphate SO42− ions. These processes are irreversible and occur only in the presence of a sufficient amount of bismuth. 相似文献
482.
通过水热或溶剂热合成的方法制备了3个Cd(Ⅱ)/Co(Ⅱ)/Zn(Ⅱ)配位聚合物[Cd(hbmb)0.5(pta)]n(1),[Co(hbmb)(1,4-bdc)]n(2)和{[Zn2(hbmb)1.5(bptc)(H2O)]·0.5hbmb·3H2O}n(3)(hbmb=1,1''-(1,6-己烷)双-(2-甲基苯并咪唑),H2pta=邻羧基苯乙酸,1,4-H2bdc=1,4-苯二乙酸,H4bptc=3,3'',4,4''-二苯甲酮四羧酸))。单晶结构解析表明配合物1是一个4-连接的二维平面网络,拓扑符号为(44·62)。配合物2是一个4-连接的二维褶皱网络,拓扑符号为(42·6)(42·63·8)。配合物3是一个(3,4,4)-连接的三重穿插网络,拓扑符号为(42·62·82)(4·62)(4·64·8)。其中配合物1属于单斜晶系,空间群为P21/c,a=0.758 32(15) nm,b=1.452 8(3) nm,c=1.911 3(5) nm,β=112.26(3)°,Z=4;配合物2属于单斜晶系,空间群为P21/n,a=1.090 8(2) nm,b=1.873 1(4) nm,c=1.301 9(3) nm,β=91.09(3)°,Z=4;配合物3属于三斜晶系,空间群为P1,a=1.119 6(2) nm,b=1.481 2(3) nm,c=1.926 6(4) nm,α=89.72(3)°,β=87.65(3)°,γ=68.28(3)°,Z=2。 相似文献
483.
Vitalii Nytka Vasyl Kordan Andrij Stetskiv Volodymyr Pavlyuk 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(6):257-262
The ternary Tb2–xNdxZn17–yNiy (x = 0.5, y = 4.83) disordered phase belongs to the structural family based on the rhombohedral Th2Zn17 structure type. The structure is maximally disordered since all the sites are occupied by statistical mixtures of atoms. The Tb/Nd mixture of atoms occupies the 6c site (site symmetry 3m). The statistical mixtures Ni/Zn consisting of more Ni atoms are located in the 6c and 9d (symmetry .2/m) sites. In the following 18f (site symmetry .2) and 18h (site symmetry .m) sites are located Zn/Ni statistical mixtures which consist of more Zn atoms. Zn/Ni atoms form three-dimensional networks with hexagonal channels that fill statistical mixtures of Tb/Nd and Ni/Zn. The Tb2–xNdxZn17–yNiy compound belongs to the family of intermetallic phases capable of absorbing hydrogen. In the structure, there are three types of voids, namely, 9e (site symmetry .2/m), 3b (site symmetry m) and 36i (site symmetry 1), in which hydrogen can be inserted, and the maximum total absorption capacity can reach 1.21 wt% H2. Electrochemical hydrogenation shows that the phase absorbs 1.03% of H2, which indicates partial filling of the voids with H atoms. 相似文献
484.
485.
Yunzhe Jiang Yidong Liu Dr. Sylvain Grosjean Dr. Volodymyr Bon Dr. Patrick Hodapp Dr. Anemar Bruno Kanj Prof. Dr. Stefan Kaskel Prof. Dr. Stefan Bräse Prof. Dr. Christof Wöll Dr. Lars Heinke 《Angewandte Chemie (International ed. in English)》2023,62(20):e202218052
Molecular machines and responsive materials open a plethora of new opportunities in nanotechnology. We present an oriented crystalline array of diarylethene (DAE)-based photoactuators, arranged in a way to yield an anisotropic response. The DAE units are assembled, together with a secondary linker, into a monolithic surface-mounted metal–organic framework (SURMOF) film. By Infrared (IR) and UV/Vis spectroscopy as well as by synchrotron X-ray diffraction, we show that the light-induced extension changes of the molecular DAE linkers multiply to yield mesoscopic and anisotropic length changes. Due to the special architecture and substrate-bonding of the SURMOF, these length changes are transferred to the macroscopic scale, leading to the bending of a cantilever and performing work. This research shows the potential of assembling light-powered molecules into SURMOFs to yield photoactuators with a directed response, presenting a path to advanced actuators. 相似文献
486.
Mykola D. Obushak Volodymyr V. Karpyak Mykola I. Ganushchak 《Heteroatom Chemistry》1999,10(6):517-525
A new approach to the synthesis of 2‐R‐5‐benzyl‐2‐thiazolines with the use of chloro‐ and bromoarylation products of allyl isothiocyanate with arenediazonium halides was elaborated. The isothiocyanates obtained were reacted with ammonia, aliphatic or aromatic amines, and sodium methoxide. The use of ammonia or weakly basic amines in this reaction allowed. Intermediate thioureas to be isolated. On the basis of 1H NMR spectra, amino–imino tautomerism of the synthesized 2,5‐disubstituted 2‐thiazolines were analyzed. 2‐Arylamino‐5‐benzyl‐2‐thiazolines exist mainly in the Z‐configuration of the imino form. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 517–525, 1999 相似文献
487.
Yuri Roiter Volodymyr Samaryk Sergiy Varvarenko Natalya Nosova Igor Tarnavchyk Jürgen Pionteck Petra Pötschke Stanislav Voronov 《Macromolecular Symposia》2004,210(1):209-217
An approach to synthesize interfacial active peroxide graft copolymers, so called precompatibilizers, which are suitable for the universal compatibilization of one special polymer with a number of other polymers, has been presented. As example, this approach is illustrated by the reactive fusion of a random peroxide copolymer (VO) with polypropylene (PP) resulting in a VOgPP precompatibilizer. A mathematical model of the process of the VOgPP synthesis and the conduction of a full-factorial experiment have allowed both the optimization of the synthesis conditions and the prediction of its proceeding. During blending PP with other polymers VOgPP localizes across the blend interphases and initiates radical processes leading to the in situ formation of final compatibilizer macromolecules, which are efficient just for the blends where they are formed. The universality of the precompatibilizer concept is demonstrated in PP blends of the thermoplastic/thermoplastic type (with polystyrene and polyethylene) and of the thermoplastic/thermoset type (with unsaturated polyester resin). 相似文献
488.
Natalya Nosova Yuri Roiter Volodymyr Samaryk Sergiy Varvarenko Yuri Stetsyshyn Sergiy Minko Manfred Stamm Stanislav Voronov 《Macromolecular Symposia》2004,210(1):339-348
Method of polyolefin surface activation via covalent grafting of polyperoxide nanolayer by free radical mechanism has been presented. The features of such the nanolayer formation under the thermoprocessing conditions, i.e.: formation of 3D crosslinked network in polyperoxide bulk; and its grafting with complete coating of polyolefin surface, -- is considered. The method provides an availability of uniformly placed peroxide groups of one type over the polyolefin surface activated, which may further be utilized for the tailored modification of polymer surfaces using the “grafting to” and “grafting from” techniques in that time when it is necessary. 相似文献
489.
Dr. Irena Senkovska Dr. Volodymyr Bon Dr. Leila Abylgazina Dr. Matthias Mendt Jan Berger Dr. Gregor Kieslich Prof. Petko Petkov Jhonatan Luiz Fiorio Dr. Jan-Ole Joswig Prof. Thomas Heine Larissa Schaper Christopher Bachetzky Prof. Rochus Schmid Prof. Roland A. Fischer Prof. Andreas Pöppl Prof. Eike Brunner Prof. Dr. Stefan Kaskel 《Angewandte Chemie (International ed. in English)》2023,62(33):e202218076
Flexible porous frameworks are at the forefront of materials research. A unique feature is their ability to open and close their pores in an adaptive manner induced by chemical and physical stimuli. Such enzyme-like selective recognition offers a wide range of functions ranging from gas storage and separation to sensing, actuation, mechanical energy storage and catalysis. However, the factors affecting switchability are poorly understood. In particular, the role of building blocks, as well as secondary factors (crystal size, defects, cooperativity) and the role of host–guest interactions, profit from systematic investigations of an idealized model by advanced analytical techniques and simulations. The review describes an integrated approach targeting the deliberate design of pillared layer metal–organic frameworks as idealized model materials for the analysis of critical factors affecting framework dynamics and summarizes the resulting progress in their understanding and application. 相似文献