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81.
Michael A. Markowitz Paul E. Schoen Paul Kust Bruce P. Gaber 《Colloids and surfaces. A, Physicochemical and engineering aspects》1999,150(1-3):85-94
Tetraethoxysilane has been co-hydrolyzed with functionalized organosilanes in a modified Stöber process to produce silica particles with amino, carboxylate or dihydroimidazole groups on the surface. The effects of reaction conditions and the loading of the functionalized organosilane on particle size was examined by TEM. Fluorescence spectroscopy of the surface amino groups covalently modified with fluorescamine, and the surface carboxylate groups with 4-bromomethyl-6,7-dimethoxycoumarin, demonstrated that these functional groups were accessible for further reaction. Changes in surface acidity and basicity caused by the presence of functional groups (amine, dihydroimidazole, carboxylate) on the particle surface were determined using an indicator titration technique. Particles with surface imidazole and amine groups and particles with surface carboxylate groups have enhanced basicity and acidity, respectively. Dihydroimidazole-modified silica had greater surface basicity than the amine-modified silica. The effect on basicity and acidity increases as the amount of added functionalized silane increases. However, this increase is nonlinear with respect to the increase in added functionalized silane. Particles with both surface dihydroimidazole and carboxylate groups demonstrated reduced surface basicity and acidity. 相似文献
82.
利用硼氢化钠还原法制备了金纳米粒子, 通过在其表面修饰链长不同的巯基羧酸, 得到了功能化纳米粒子. 利用荧光发射、紫外吸收和圆二色谱等手段研究了功能化金纳米粒子与蜂毒素分子之间的相互作用及其所诱导的蛋白质分子的构象变化. 研究结果表明, 功能化修饰的金纳米粒子可通过静电相互作用吸附蜂毒素(Melittin)并诱导其α-螺旋结构的形成, 且这种效应与巯基羧酸分子的链长直接相关. 相似文献
83.
Jafar Akbari 《Tetrahedron letters》2009,50(29):4236-4238
A sulfonic acid functionalized ionic liquid is used as a Brønsted acid catalyst for the one-pot, three-component synthesis of α-aminophosphonates from aldehydes and ketones at room temperature in water. This homogeneous catalytic procedure is simple and efficient and the catalyst can be reused at least six times without any noticeable decrease in catalytic activity. 相似文献
84.
以羟基化多壁碳纳米管(MWNT-OH)为引发剂,通过原位负离子开环聚合制备了生物相容性多羟基超支化聚缩水甘油接枝的碳纳米管(MWNT-HPG),利用酯化反应将荧光分子罗丹明6B标记于聚合物上,然后聚合物上的羟基和丁二酸酐反应将其转化为羧基.用TGA、FTIR、TEM、SEM等手段对产物进行了表征.用靶向表皮生长因子受体(EGFR)的小分子多肽D4修饰了所得的荧光功能化碳纳米管,并将其做为受体介导靶向肿瘤细胞的纳米载体,通过噻唑蓝(MTT)比色法评价功能化碳纳米管作为载体的安全性.用荧光显微镜观察其与人肺腺癌细胞SPCAI细胞的结合状态.结果证明了其有希望成为受体介导靶向肿瘤系统的纳米载体. 相似文献
85.
86.
Fischer indole cyclization of phenylhydrazine and various ketones using carboxyl-functionalized ionic liquid, 1-carboxymethyl-3-methylimidazolium tetrafluoroborate (abbreviated as [cmmim][BF4]) as catalyst was successfully performed. The yields of thetarget compounds were 80-92%, the purities were 96-98%. The catalyst could be rocovered and reused for at least six times without significant loss in activity. 相似文献
87.
Abstract A new diol-functionalized ionic liquid, 2,2-bis(1-(1-methylimidazolium)methylpropane-1,3-diol hexafluorophosphate, was synthesized
and applied as a facile, efficient, and recoverable “capture and release” reagent for aldehydes. This method has the advantages
of homogeneous reaction, heterogeneous separation, and recyclable uses.
Graphical abstract
相似文献
88.
Fabio Carniato Giuliana Gervasio Enrico Sappa Andrea Secco 《Journal of organometallic chemistry》2009,694(26):4241-4249
The complex Co2(CO)6[μ-η2-(H3CCCCH2CH2OH)] (1) with the ligand 3-pentyn-1-ol (pol) has been synthesized following established procedures. Its structure has been determined by X-ray analysis. The complex Co2(CO)6(mbo) (mbo = 2-methyl-3-butyn-2-ol, HCCC(CH3)2OH), (3), along with the already known Co2(CO)6(bud) (bud = 1,4-butyn-diol, HOCH2CCCH2OH) (2), and Co2(CO)8 were reacted with 2(diphenylphosphino)ethyl-triethoxysilane [Ph2PCH2CH2Si(OCH2CH3)3] (dpts) and tris(hydroxymethyl)phosphine [P(CH2OH)3] (thp). With dpts, mono- and di-substituted complexes were obtained: these were characterized by analytical and spectroscopic techniques. The structures of Co2(CO)6(dpts)2 (5) and of Co2(CO)4(pol)(dpts)2 (8) have been determined by X-ray analysis.Complex (1) was reacted with 3-(triethoxysilyl)propyl isocyanate [(H3CCH2O)3Si(CH2)3NCO] (tsi): the new complex Co2(CO)6[H3CCCCH2CH2OC(O)NH(CH2)3Si(OCH2CH3)3] (9) was obtained and spectroscopically characterized. The complex has also been reacted with tetraethyl orthosilicate (teos); a new inorganic-organometallic material was obtained. Complex (5) has been grafted on the mesoporous material SBA-15. The hybrid inorganic-organometallic materials obtained have been characterized by inductively coupled plasma-mass spectrometry (ICP-MS), infrared spectroscopy (FT-IR) under vacuum conditions, X-ray diffraction (XRD) and scanning electron microscopy coupled to EDS probe (SEM-EDS). 相似文献
89.
A series of air-stable, robust and highly active palladium based precatalysts of amido-functionalized N-heterocyclic carbenes for the Suzuki-Miyaura C-C cross-coupling reaction has been designed. In particular, the [1-R-3-{N-(benzylacetamido)imidazol-2-ylidene]2PdCl2 [R = i-Pr (1c) and CH2Ph (2c)] complexes efficiently carried out the Suzuki-Miyaura coupling of the aryl bromide and iodide substrates with phenyl boronic acid in good to excellent yields in air at 90 °C in 12 h. Quite interestingly, of these palladium precatalysts, the i-propyl derivative (1c) exhibited superior activity as compared to the benzyl derivative (2c). The density functional theory (DFT) studies carried out on the 1c and 2c complexes revealed the strong σ-donating nature of the NHC ligand as reflected in their high d/b ratio [i.e. forward σ-donation (d) to backward π-donation (b)] of these complexes and, thus, point towards greater stability of the Pd-NHC interaction in these complexes. 相似文献
90.
George O. Buica Christophe Bucher Jean‐Claude Moutet Guy Royal Eric Saint‐Aman Eleonora M. Ungureanu 《Electroanalysis》2009,21(1):77-86
Complexing polymer‐coated electrodes have been synthesized by oxidative electropolymerization of ethylenediamine tetra‐N‐(3‐pyrrole‐1‐yl)propylacetamide (monomer L ). The presence of four polymerizable pyrrole fragments on the same EDTA skeleton was thought to confer enhanced rigidity and controlled dimensionality to the resulting complexing materials, which were used for the electrochemical detection of Hg(II), Cu(II), Pb(II) and Cd(II) ions by means of the chemical preconcentration‐anodic stripping technique. The polyamide electrode material showed particularly a significant selectivity towards mercury ions, even in the presence of a large excess of other metal cations. Moreover, the use of imprinted polymer‐coated electrodes prepared by electropolymerization of L in the presence of metal cations turned out to significantly improve the detection limits, down to 5×10?10 mol L?1 for Hg(II) and Cu(II) species. 相似文献