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991.
992.
A new fluorinated polystyrene bearing a p-sulbstiuted perfluoro[1-(2-fluorosulfonylethoxy)]ethyl group was synthesized via one-electron oxidation of polystyrene by perfluoro[2-(2-fluorosulfonylethoxy)]propionyl peroxide at different peroxide to polystyrene molar ratios.The yield of perfluoroalkylation decreases with the increase of the reactant molar ratio.The modified polymer has been characterized by various techniques:the ring pefluoro[1-(2-fluorosulfonylethoxy)]ethylation has been proved by FT-IR and ^19FNMR;the X-ray photoelectron spectra(XPS) show the maximum binding energy of F18,O18,C18(two kinds of carbon atoms,namely C-H and C-F)and S2p,respectively; desulfonylation of the fluorinated polystyrene appearing at 217℃ has been found by its thermogravimetric analysis (TGA).The determinations of contact angle,refractive index and glass transition temperature of the modified polymer have disclosed that when the contact angle increases with the increase of the molar ratio,the refractive index and glass transition temperature decrease.The polydispersity values indicate that the degradation of the polymer chains did not occur during the reaction. 相似文献
993.
Fe2O3/Al2O3催化氧化苯偶姻制备苯偶酰 总被引:13,自引:1,他引:13
考察了几种常用载体负载金属氧化物催化分子氧氧化苯偶姻制备苯偶酰的性能 ,发现氧化铁、三氧化二铝催化活性较高,稳定性较好。以吡啶为溶剂,用483K下 活化的含铁14.8%的氧化铁/三氧化二铝作催化剂,当其用量为苯偶姻用量20% (质量分数),253K下反应1h,苯偶酰平均产率98.1%。用IR,MS,和^1H NMR光 谱对其结构进行了表征。 相似文献
994.
Guo-dong Liang Jun-ting Xu Zhi-qiang Fan 《高分子科学》2006,(4):341-344
Thin film morphology of a symmetric semicrystalline oxyethylene/oxybutylene diblock copolymer (E76B38) on silicon was investigated by tapping mode atomic force microscopy (AFM). It is found that the nascent thin film is composed of multiple polymer layers having mixed thicknesses of L ≈ L0 and L ≈ L0/2 (L0 is the long period of the block copolymer in bulk) besides the first layer near the substrate. This shows that the crystalline domain in the block copolymer consists of double poly(oxyethylene) layers. Annealing leads to disappearance of the polymer layers with thickness L ≈L0/2, indicating that such polymer layers are metastable. 相似文献
995.
Assembly of [Ag(CN)2]^- units with M(Ⅱ)-diamine complex cations [Cu(LN-N)2]^2+, where LN-N represents L2-diaminopropane (pn) and ethylenediamine (en), afforded two complexes, [Cu(pn)2][Ag2(CN)4] (1) and [Cu(en)2][Ag3(CN)5] (2), which were characterized by elemental analysis, IR, UV-Vis and ESR spectra. Single crystal X-ray analyses show that these complexes have 2D and 3D architectures through silver-silver interactions and other weak interactions. The luminescence behaviors of the two complexes were also studied by means of emission spectra. 相似文献
996.
Synthesis and Structural Characterization of [Mn(sapn)(H2O)2]Br 总被引:1,自引:0,他引:1
1 INTRODUCTION Many of the recent advances in the coordination chemistry of manganese have been driven by the involvement of the manganese in several biological redox-active systems[1,2], of which the most important is the oxygen-evolving complex (EOC) of photosystem II (PS II) in green plants [3]. Since the preparations and structural characterizations of the complexes containing N,O-donor ligands have been studied extensively as simple active-site models for the photosystem II[4,5]… 相似文献
997.
998.
Lophenol, cholest-4α-methyl-7-en-3β-ol (1), obtained from Dracaena cochinchinensis (Lour.) S. C. Chen, was structurally modified. It was acetylated to protect 3β-hydroxyl group, and then oxidised by selenium dioxide in acetic acid to give cholest-4a-methyl-8-en-3β, Ta-diol diacetate (3). This compound 3 is unstable in chloroform solution or when heated and easily converted to a diene compound, cholest-4a-methyl-7,14-dien-3β-ol acetate (4). The structures of 3 and 4 were elucidated by means of IR, ^1H NMR, ^13C NMR and MS, and the absolute configuration of 3 was established by X-ray crystallography. The property of 3 was also discussed in this paper. Both 3 and 4 are new compounds and were reported for the first time. 相似文献
999.
稀土氨基酸固体络合物的合成及结构分析进展 总被引:16,自引:2,他引:16
本文综述了稀土氨基酸络合物的合成,以及应用红外、核磁、X-射线衍射、热分析等方法进行结构分析研究的进展情况。 相似文献
1000.
采用SCC-DV-Xα方法对α-Keggin结构硅钼二电子还原态杂多蓝阴离子[SiMo2(V)Mo10(VI)O40]6-和它的混合型钒取代物[SiV2(V)Mo10(VI)O40]6-进行了量子化学计算,获得了轨道能级、费米能级、各原子价电子布居、自由价态密度分析和分子轨道成分等信息.理论分析表明该杂多阴离子中所有原子Si、Mo、V、Oa、Ob、Oc和Od都参与反应,Oc和Od的成键能力较强,化学活性较大,有力地支持了实验结果.中心硅氧四面体结构发生畸变很小,但构成三金属簇的八面体结构都发生了较明显的畸变,其整体仍然保持α-Keggin结构.钒的取代增强了Mo2VO13三金属族中Od的活性.预测这两种杂多阴离子都有被继续还原和取代的趋势,[SiMo2(V)Mo10(VI)O40]6-的趋势更强. 相似文献