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101.
102.
结合Aa-Bb,Cc型缩聚反应,给出了溶胶中含内环化的溶胶-凝胶分配公式及凝胶化条件。 相似文献
103.
104.
105.
采用原子转移自由基聚合与片段印迹技术相结合的方法,以磺胺类物质的结构类似物4,6-二氯嘧啶为模板合成印迹聚合物。以4,6-二氯嘧啶(模板)︰甲基丙烯酸缩水甘油酯(功能单体)︰2,2'-联吡啶(配体)的摩尔比为10︰180︰1合成印迹聚合物。控制反应温度为60℃,反应时间为5 h。印迹聚合物的吸附量为1.48 mg/g,非印迹聚合物的吸附量为0.73 mg/g。以合成的聚合物为新型材料,对样品中的兽药残留进行选择性分离、富集,结果表明印迹聚合物的选择吸附能力明显优于非印迹聚合物。通过电镜扫描对聚合物的表面形态进行了表征。 相似文献
106.
107.
We show there is a computable linear order with a
initial segment that is not isomorphic to any computable linear order. 相似文献
108.
Microwave activation of electrochemical processes: enhanced electrodehalogenation in organic solvent media 总被引:2,自引:0,他引:2
Tsai YC Coles BA Compton RG Marken F 《Journal of the American Chemical Society》2002,124(33):9784-9788
The effect of high-intensity microwave radiation focused into a "hot spot" region in the vicinity of an electrode on electrochemical processes with and without coupled chemical reaction steps has been investigated in organic solvent media. First, the electrochemically reversible oxidation of ferrocene in acetonitrile and DMF is shown to be affected by microwave-induced thermal activation, resulting in increased currents and voltammetric wave shape effects. A FIDAP simulation investigation allows quantitative insight into the temperature distribution and concentration gradients at the electrode / solution interface. Next, the effect of intense microwave radiation on electroorganic reactions is considered for the case of ECE processes. Experimental data for the reduction of p-bromonitrobenzene, o-bromonitrobenzene, and m-iodonitrobenzene in DMF and acetonitrile are analyzed in terms of an electron transfer (E), followed by a chemical dehalogenation step (C), and finally followed by another electron-transfer step (E). The presence of the "hot spot" in the solution phase favors processes with high activation barriers. 相似文献
109.
Andrew J. Mountford Simon J. Lancaster Simon J. Coles 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):m401-m404
The title ionic solid, [Ti(C2H6N)3(C2H7N)2][Ti(C18BF15N)(C18H2BF15N)Cl(C2H7N)2]·C7H8, (I), comprises a cation with three dimethylamide ligands in the equatorial plane and two dimethylamine ligands positioned axially in a trigonal–bipyramidal geometry about the central TiIV atom. The anion has a highly distorted octahedral structure. The two dimethylamine ligands are coordinated mutually trans. The chloride is trans to the tris(pentafluorophenyl)boron–amide, while the sixth coordination site is occupied by an ortho‐F atom of the tris(pentafluorophenyl)boron–amide group in a trans disposition with respect to the tris(pentafluorophenyl)boron–nitride ligand. The most significant feature of the anion is the presence of an unprecedented terminal Ti[triple‐bond]N moiety [1.665 (2) Å], stabilized by coordination to B(C6F5)3, with a Ti[triple‐bond]N—B angle of 169.50 (19)°. 相似文献
110.
I.R. Butler L.J. Hobson S.J. Coles M.B. Hursthouse K.M. Abdul Malik 《Journal of organometallic chemistry》1997,540(1-2):27-40
The synthesis of a series of ferrocenylanthracene derivatives is described, utilising the palladium catalysed coupling reaction of 1,1′-bis(chlorozincio)ferrocene with halo-anthracenes. Bis-1,1′-(9-anthracenyl)ferrocene (1) was characterised by single crystal X-ray diffraction and shows an eclipsed ferrocenyl geometry. X-ray crystallographic studies indicate that there are no clear stacking interactions of either an intra- or intermolecular nature between the anthracenyl rings in the structure. A series of 9- and 10-disubstituted ferrocenylanthracene derivatives has also been prepared. In each case the palladium catalyst (Pd(dppf)Cl2) is recovered in a modified form, e.g. as the [(dppf)PdBr(9-anthracenyl)] complex in the synthesis of bis-1,1′-(9-anthracenyl)ferrocene. The single crystal X-ray structure of one such palladium complex [(dppf)PdBr-9-(10-chloroanthracenyl)] (15a) has been determined in a case where chloride/bromide exchange had occurred in the palladium complex intermediate. The potential application of compound 1 as synthon for the construction of a molecular sensing device is discussed. Cyclic voltammetry and fluorescence studies have been carried out for selected derivatives. 相似文献