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981.
The monolayer Al2O3:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing
at 700 °C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy,
and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before
and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly
dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration,
and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption
can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness
was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles.
On the base of film thickness results, the multilayer Al2O3:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer
films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 °C for 70 h in air. It can
be concluded that film thickness is an important factor to control the thermal stability of Al2O3:Ag thin films as high-temperature solar selective absorbers. 相似文献
982.
F. Song Å. Monsen Z.S. Li E.-M. Choi J.L. MacManus-Driscoll J. Xiong Q.X. Jia E. Wahlström J.W. Wells 《Surface science》2012,606(23-24):1771-1776
The surface and near-surface chemical composition of BiFe0.5Mn0.5O3 has been studied using a combination of low photon energy synchrotron photoemission spectroscopy, and a newly developed maximum entropy finite element model from which it is possible to extract the depth dependent chemical composition. In the uppermost few unit cells, an overabundance of Bi, and a deficiency of Fe and Mn are observed. In deeper layers, the measurements are consistent with bulk-like stoichiometry.Additionally, a definitive identification of all the observed species together with their abundance and depth dependence is given, and the mixed Fe and Mn valencies are estimated. In addition to the expected bulk valencies Mn3 + and Fe3 +, some Fe2 + and a small amount of Mn4 + are also observed. The maximum entropy finite element model demonstrated here is also discussed in more general terms and its potential application to the broader field of perovskite thin films is made apparent. 相似文献
983.
光热敏折变玻璃及其布拉格体光栅特性研究 总被引:3,自引:1,他引:2
采用高温二次化料的方法制备了一种SiO2-Al2O3-ZnO-Na2O(F、Br)玻璃体系的光热敏折变(PTR)玻璃,通过紫外曝光、透射率光谱、X射线衍射(XRD)和差热分析等方法研究了其光热敏析晶机理。研究表明,PTR玻璃的光敏区为280~350nm,工作区为400~2700nm,最佳成核温度和析晶温度分别为490℃和595℃,析晶组分为NaF晶体。采用双光束干涉方法与"两步法"的热处理工艺在PTR玻璃中制备了周期为1000mm-1的布拉格体光栅,光栅的相对衍射效率达到91%,并验证了制备的布拉格体光栅具有角选择滤波能力。 相似文献
984.
A reliable LC-MS method has been applied for the separation and identification of major constituents of the rhizome of Smilacis glabrae. Identification of the constituents was carried out by interpretation of their retention time, and MS and MS/MS data, especially by comparing these with Sarcandra glabra under the same LC-MS conditions, as well as the data provided by the literature. Thirty-three compounds, including catechin derivatives, flavanonols, phenolic acid derivatives and phenylpropanoid glycosides were either identified or tentatively characterized. Among them, compound 12 was deduced to be a new phenylpropanoid-substituted catechin. Fragmentation behaviors of the three major categories of compounds were also investigated. This UPLC-PDA/ESI-MS(n) method was effective for the separation and identification of the constituents and could be the basis for the comprehensive quality control of Smilacis glabrae. 相似文献
985.
Frank Seela Hui Mei Hai Xiong Simone Budow Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(10):o395-o398
The title compound [systematic name: 4‐amino‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐5‐ethynylpyrimidin‐2(1H)‐one], C11H13N3O4, shows two conformations in the crystalline state. The N‐glycosylic bonds of both conformers adopt similar conformations, with χ = −149.2 (1)° for conformer (I‐1) and −151.4 (1)° for conformer (I‐2), both in the anti range. The sugar residue of (I‐1) shows a C2′‐endo envelope conformation (2E, S‐type), with P = 164.7 (1)° and τm = 36.9 (1)°, while (I‐2) shows a major C3′‐exo sugar pucker (C3′‐exo‐C2′‐endo, 3T2, S‐type), with P = 189.2 (1)° and τm = 33.3 (1)°. Both conformers participate in the formation of a layered three‐dimensional crystal structure with a chain‐like arrangement of the conformers. The ethynyl groups do not participate in hydrogen bonding, but are arranged in proximal positions. 相似文献
986.
A graphene-cobalt oxide based needle electrode for non-enzymatic glucose detection in micro-droplets
Wang X Dong X Wen Y Li C Xiong Q Chen P 《Chemical communications (Cambridge, England)》2012,48(52):6490-6492
A novel graphene-cobalt oxide hybrid needle-like electrode was fabricated for non-enzymatic glucose detection. Taking advantage of its small size, the needle electrode can probe glucose in a micro-droplet with high sensitivity. 相似文献
987.
Y Guan M Ni X Hu T Xiao S Xiong C Lin L Wang 《Chemical communications (Cambridge, England)》2012,48(68):8529-8531
Ureidopyrimidinone functionalized pillar[5]arene (UPyP5) was synthesized and employed to complex with a bisparaquat derivative (G) to form supramolecular polymers at relatively high concentration. The orthogonal binding interactions including quadruple hydrogen bonding and host-guest interaction should play vital roles in the construction of this linear assembly. 相似文献
988.
Li WY Xiong XQ Zhao DM Shi YF Yang ZH Yu C Fan PW Cheng MS Shen JK 《Molecules (Basel, Switzerland)》2012,17(5):5497-5507
A series of novel quinoline-3-carboxamide derivatives 10-17 and 23-27 were designed and synthesized as cholesteryl ester transfer protein (CETP) inhibitors. All of them exhibited activity against CETP. Particularly, compounds 24 and 26 displayed the best activity against CETP with the same inhibitory rate of 80.1%. 相似文献
989.
G Xie N Chen LW Soromou F Liu Y Xiong Q Wu H Li H Feng G Liu 《Molecules (Basel, Switzerland)》2012,17(7):8159-8173
The objective of this study was to test the hypothesis that p-cymene can attenuate acute lung injury induced by lipopolysaccharide (LPS) in vivo. In the mouse model of LPS-induced acute lung injury, intraperitoneal preconditioning with p-cymene resulted in a significant reduction of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), lung water gain, inflammatory cell infiltration, lung tissue myeloperoxidase activity. In addition, p-cymene blocked the phosphorylation of IκBα protein and mitogen-activated protein kinases (MAPK) signaling pathway activation. Histopathologic examination of lung tissue indicated that p-cymene treatment markedly decreased focal thickening, congestion, pulmonary edema, and inflammatory cells infiltration. The results showed that p-cymene had a protective effect on LPS-induced ALI in mice. 相似文献
990.
Zhong Lu Rong Chen Ruiguan Fu Jinyan Xiong Yeli Hu 《Journal of inclusion phenomena and macrocyclic chemistry》2012,73(1-4):313-320
Resveratrol (Res) is a plant-based polyphenol compound and is known to inhibit the growth of a variety of cancer cells and protect lipoproteins against oxidative damage. However the poor solubility and labile property may constitute a serious problem for its bioavailability. The problem could be overcome by the formation of inclusion complexes with cyclodextrins (CDs). The aim of this work is to include Res by β-cyclodextrin (β-CD) and 2-hydroxypropyl-β-cyclodextrin (HP-CD) to form the Res/β-CD and Res/HP-CD inclusion complexes and evaluate their cytotoxicity on cancer cells and inhibition of lipid peroxidation activity. The complexes are characterized by powder X-ray diffraction, fourier transform infrared spectroscopy and scanning electron microscopy. The cytotoxicity of the two complexes has been evaluated by methylthiazoletetrazolium reduction assay on two cancer cell lines (cervical carcinoma cells HeLa and hepatocellular liver cancer cells Hep3B) and one normal cell line (umbililical vein endothelial cell HUVEC). The results showed that the two complexes exhibit high cytotoxicity on two cancer cells, especially for Hep3B, and show no significant effect on normal cells. The Res/HP-CD complex shows higher cytotoxicity on the two cancer cells than that of the Res/β-CD complex. The inhibition of lipid peroxidation induced by Fe2+/ascorbate of the two inclusion complexes has been determined by thiobarbituric acid assay. The inhibition rate shows a linear increase with the increase of CDs concentration, and the Res/HP-CD complex shows stronger inhibition activity than that of the Res/β-CD complex. The results of this work indicate a potential for using the Res/CD complexes to inhibit human cancer growth and lipoproteins peroxidation. 相似文献