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101.
Metal‐pernitride compounds belong to a class of chemical systems in which both the complex ions and the non‐bonding electrons may play roles in the formation of their modified crystalline structures. To investigate this issue, the energy landscapes of pernitrides of metals with different maximum valence (M=Ca, Sr, Ba, La, and Ti) were globally explored on the ab initio level at standard and high pressures, thereby yielding possible (meta)stable modifications in these systems together with information on how the landscape changed as function of the valence of the metal cation. For all of the systems in which no compounds had been synthesized so far, we predicted the existence of kinetically stable modifications that should, in principle, be experimentally accessible. In particular, TiN2 should crystallize in a new structure type, TiN2‐I. 相似文献
102.
Chemoselective hydrogenation of unsaturated monoperoxyketals provides new methodology for the synthesis of saturated and allyl hydroperoxides. 相似文献
103.
Alexander V. Zhukov Roland Bouffanais Anastasia V. Pak Mikhail B. Belonenko 《Physics letters. A》2013
In this study we investigate the propagation of extremely short optical pulses in a thin film formed by a graphene grown on a boron nitride substrate. Conduction electrons of the system are described on the basis of the long-wavelength effective Hamiltonian in the case of low temperatures; the electromagnetic field being taken into account within the framework of the classical Maxwell equations. The time evolution of the pulse?s shape for different speeds and maximum amplitudes of an extremely short pulse is analyzed. 相似文献
104.
近年来,石墨相氮化碳(g-C3N4)以其合适的带隙宽度、丰富的活性位点和成本低廉等优点,成为新兴的可见光响应非金属光催化剂,被广泛应用于光催化降解有机污染物领域。然而,纯g-C3N4对可见光的吸收效率较低且光生电子和空穴复合速率快,导致其光催化活性处于较低水平。基于g-C3N4的非金属特性,通过非金属掺杂可以有效提高g-C3N4的光催化性能,引起了学者们的广泛关注。本文介绍了目前非金属掺杂g-C3N4复合材料常见的制备方法,着重归纳了不同类型的非金属掺杂g-C3N4光催化降解水中有机污染物的相关研究进展,探讨其作为光催化剂在可见光条件下降解有机污染物的相关机理。最后,提出目前g-C3N4基复合材料在光催化降解水中有机污染物中所面临的挑战,旨在为非金属掺杂g-C3... 相似文献
105.
106.
K. C. Swallow K. Taghizadeh S. Weakland E. F. Plummer W. F. Busby Jr A. L. Lafleur 《International journal of environmental analytical chemistry》2013,93(2-4):113-122
Abstract We have studied the photooxidation of selected polycyclic aromatic hydrocarbons (PAH) in the presence of Ti(IV)oxide in a mixed solvent system consisting of N-methylpyrrolidinone (NMP) and water. Reaction rates for the photooxidation of acenaphthylene and pyrene were investigated by monitoring the disappearance of the PAH substrate from the reaction mixture as a function of time. For both compounds plots of In Co/Ct, as a function of time yielded straight lines, indicating first order kinetics with respect to the substrate. With an initial acenaphthylene concentration of 1.0 gL?1 the first order reaction rate constant was 0.19 hr?1 and the half life was 3.7 hr. With an initial pyrene concentration of 0.2 gL?1 the first order reaction rate constant was 0.0285 hr?1 and the half life was 24 hr. The photoproducts were characterized by high performance liquid chromatography with diode-array detection (HPLC/DAD) and by liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (APCI/LC-MS). Although a number of simple oxidation products were identified the bulk of the photoproducts consisted of the parent PAH substituted with one or more solvent (NMP) molecules. The product mixtures from the photooxidation of the non-mutagens acenaphthylene and pyrene were found to be also non-mutagenic in our Salmonella typhimurium forward mutation assay. 相似文献
107.
Titanium tetrachloride in ethyl acetate can be reduced by Mg powder to the corresponding low‐valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 38–85% yields within 15–60 min at rt with stirring. 相似文献
108.
Jingyi Cai Haoshan Wei Prof. Yong Zhang Rui Cai Dr. Xueru Zhang Prof. Yan Wang Prof. Jiaqin Liu Prof. Hark Hoe Tan Prof. Ting Xie Prof. Yucheng Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(25):7300-7306
Efficient separation of photogenerated electron–hole pairs is a crucial factor for high-performance photocatalysts. Effective electron–hole separation and migration could be achieved by heterojunctions with suitable band structures. Herein, a porous SrTiO3/SrSO4 heterojunction is prepared by a sol-gel method at room temperature followed by an annealing process. XRD characterization suggests high crystallinity of the heterostructure. A well-defined interface between the two phases is confirmed by high-resolution (HR)TEM. The photocatalytic H2 evolution productivity of the SrTiO3/SrSO4 heterojunction with Pt as co-catalyst reaches 396.82 μmol g−1 h−1, which is 16 times higher than that of SrTiO3/Pt. The boosted photocatalytic activity of SrTiO3/SrSO4/Pt can be ascribed to the presence of SrSO4, which promotes the transfer and migration of photogenerated carriers by forming the heterojunction and porous structure, which provides a large amount of active sites. This novel porous heterostructure brings new ideas for the development of high-efficiency photocatalysts for H2 release. 相似文献
109.
110.
《Journal of Coordination Chemistry》2012,65(2-3):169-185
Abstract The synthesis of Ti(iso)Cl2 (iso = the dianion of 2, 2′-ethylidenebis(4, 6-di-rert-butylphenol)) is described. Metathesis reactions of this complex with Grignard reagents, as well as alkali metal salts, yielded Ti(iso)X2 (X = CH3, CH, Ph, CH2SiMe3, OCMe3, or NMe2). Reactions of the Ti-C bond in Ti(iso)(CH3)2 toward halogens, active hydrogen compounds, and acetone were studied. In addition. Ti(iso)(X)(Y) (X = CI or CH3; Y = OC6H2-2, 6-tBu2-4-Me) could be prepared with the formation of only one coordination isomer. The new complexes have been thoroughly characterized by 1H and 13C NMR spectroscopies. The solid state structure of Ti(iso)Cl2 was determined via single crystal X-ray diffraction methods. The complex is monomeric, with approximately tetrahedral geometry about the titanium ion. The structure of Ti(iso)Cl2 is compared to that of Ti(ultra)Cl2 (ultra = the dianion of 2, 2′-mefhylenebis(6-tert-butyl-4-mefhylphenol)), which was redetermined to greater precision. 相似文献