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881.
本文报道一类新型大环聚醚的合成.在以1,7-二氧杂-4,10-二氮杂环十二烷(1a)及1,7,10,16-四氧杂-4,13-二氮杂环十八烷(1b)中的两个仲胺上进行含醚键的卤代烷取代反应,获得一批带有两个含有侧链醚键的新型冠醚.以碳酸钾为缩合剂,所得冠醚碱金属配合物经酸分解及四甲基氢氧化铵处理后,得游离的大环聚醚. 用溶解度法初步测定了这类冠醚对碱金属的配位性能.结果指出,其母环及侧链上氧原子数的多少及碱金属离子半径的大小均影响配合物的稳定性,其中有些冠醚对碱金属有良好的配位能力,有的还具有优异的选择性,例如N,N′-β-甲氧基乙基-1,7-二氧杂-4,10-二氮杂环十二烷(13a)对钾及钠离子的选择比大于18-c-β,并比4,4′(5′)-二甲基苯并-30-c-10还高. 相似文献
882.
用X射线单晶衍射方法测定了二乙酰丙酮氧钒与γ-甲基吡啶加合物VO(CH_3COCHCOCH_3)_2·NC_5H_4CH_3的晶体结构.晶体属空间群Cm(C_8~3),晶胞参数α=8.288(3)A,b=13.983(7)A,c=11.459(4)A,β=138.32(2)°,Ζ=2.由SYNTEX R3型四圆衍射仪收集了876个独立衍射数据,以Patterson重原子法导出粗结构,经块矩阵最小二乘法修正,最终得偏离因子R=0.093.所得结果与相应吡啶1∶1加合物的分子结构参数进行了对比,探讨了VO(acac)_2·L型这类化合物的结构化学特点,并对第六位配键的键型进行了分析和讨论. 相似文献
883.
The stepwise formation constants of complex compounds formed from N-(m-substituted-phenyl) glycines (m-RC6H4NHCH2COOH(m-RPhG), R = H, CH3, CH3O, Cl, NO2) with Cu(II) and Ni(II) were determined by pH method at 15, 25 35`C in 30% (V/V) ethanol solution in the presence of 0.1m NaClO4. Their thermodynamical parameters were calculated. It was found that the N-(m-substituted-phenyl) glycine complexes also showed linear free energy relationships between the stability of complex compounds and the base strength of the ligands just as the para-substituted isomers reported previously. Linear relationships not only existed between their thermodynamical parameters and the base strength of the ligands but also existed between the formation enthalpy of complex compounds and the neutralization enthalpy of the ligands and between the formation entropy of complex compounds and neutralization entropy of the ligands as well. 相似文献
884.
稀土元素的电分析化学研究 VIII.钆与邻苯二酚紫的配合吸附波 总被引:1,自引:0,他引:1
In certain supporting electrolytes, pyrocatechol violet (PV) may be reduced at single-sweep polarograph and a well-defined wave can be observed. The height of this wave decreases when Gd3+ is added into the solution and a sharp-peaked new wave is observed at more negative potentials. The height of this new wave is proportional to the concentration of gadolinium added. NH4Cl-(CH2)6N4 mixture (pH 5.5) was chosen as the suitable supporting electrolyte, in which the new wave of the Gd3+-PV complex is higher and the difference of peak potentials between PV and complex is larger. The linear relationship between wave height and concentration of Gd3+ holds in the range of 1X10-6-2X10-5 M. In this system other rare earth elements exhibit similar wave peaks. This wave has been proved to be an adsorptive-complex wave by several experiments. 相似文献
885.
稀土元素的电分析化学研究 X:钆-茜素红的极谱配合吸附波的研究 总被引:1,自引:0,他引:1
In a supporting electrolyte containing 2X10-4M Alizarin Red S, 0.1M NH3-NH4Cl and at pH 9.6, we obtained an adsorptive complex wave of gadolinium-Alizarin Bed S by single-sweep polarography. The peak potential of the derivative wave is -0.69V (S. C. E.). The limit of detection for gadolinium is 6X10-8M. We have determined the composition of the complex which is 1:3 GD-Alizarin Red S and confirmed that the wave is an adsorptive complex wave. The electrode processes may be presented as follows: Gd3+ + 3HL2- + 3NH3 = (GdL3)6- + 3(NH4)^+ (Chemical reaction) (GdL3)6- = (GdL3)ad6- (Surface process) The total electrochemical reaction is (GdL3)ad6- + 6e + 6(NH4)^+ = (Gd(LH2)3)ad6- + 6NH3 相似文献
886.
In this paper the behaviour of mer-and fac-(Rh(NH3)3Cl3) in aqueous solution at room temperature is reported. The experimental results show that some obvious differences exist between the properties of mer-and fac-(Rh(NH3)3Cl3) coordination compounds in aqueous solution at room temperature. The fac-(Rh(NH3)3Cl3) is relatively stable, and the mer-(Rh(NH3)3 Cl3) is unstable. When one of its Cl^- is replaced by H2O(RH(NH3)3)(OH)2Cl2)Cl is formed. The mechanism of anti-tumour action of platinum compounds is briefly discussed. 相似文献