全文获取类型
收费全文 | 96篇 |
免费 | 6篇 |
国内免费 | 28篇 |
专业分类
化学 | 123篇 |
晶体学 | 4篇 |
物理学 | 3篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 14篇 |
2014年 | 9篇 |
2013年 | 22篇 |
2012年 | 8篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有130条查询结果,搜索用时 234 毫秒
31.
《Electroanalysis》2006,18(9):888-893
A poly(vinyl chloride)‐based membrane of dimethyl 1‐acetyl‐8‐oxo‐2,8‐dihydro‐1H‐pyra‐zolo[5,1‐a]isoindole‐2,3‐dicarboxylate as a neutral carrier with sodium tetraphenylborate (NaTPB) as an anion excluder and 2‐nitrophenyl octyl ether (NPOE) as plasticizer was prepared and investigated as a Ba(II)‐selective electrode. The electrode exhibits a Nernstian slope of 29.7±0.4 mV per decade over a wide concentration range (1.0×10?6 to 1.0×10?1 M) with a detection limit of 7.6×10?7 M between pH 3.0 and 11.0. The response time of the sensor is about 10 s and it can be used over a period of 2 months without any divergence in potential. The proposed membrane sensor revealed good selectivity for Ba(II) over a wide variety of other metal ions. It was successfully used in direct determination of barium ions in industrial wastewater samples. 相似文献
32.
Assia Djeghri Fadila Balegroune Achoura Guehria-Laidoudi Thierry Roisnel 《Journal of chemical crystallography》2007,37(2):97-101
The title compound [Cu2(OOC-(CH2)6-COO)2] was synthesized and its crystal structure has been determined by single crystal X-ray diffraction methods. The complex crystallizes
in the triclinic space group P-1 with a=5.1077(5) ?, b=8.362(2) ?, c=11.378(2) ?, α=93.773(6)°, β=97.587(9)°, γ=90.493(’9)°
and D
cal=1.629 mg/m3 for Z=1.
The structure is polymeric and consists of discrete anhydrous centrosymmetric binuclear units [Cu2(OOC-(CH2)6-COO)2]. The two copper(II) centres bridged by the suberate groups in a syn-syn conformation, are in pentacoordinated distorted
square-pyramidal coordination environment, with an intramolecular Cu–Cu distance of 2.5793(10) ?. Each binuclear unit, related
to the next through μoxo bridges with a Cuμoxo–Cuμoxo separation of 3.2326(10)?, defines infinite chains of one-edge sharing CuO5 square pyramid. 相似文献
33.
Hongwei Chang Yannan Zhou Xiaoli Zheng Wei Liu Prof. Qun Xu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(61):e202201811
The development of an efficient strategy for fabricating two-dimensional metal-organic framework (MOF) nanosheets with high yield and high stability is desirable. Herein, we demonstrate for the first time that large, single-layer 2D nickel-benzene dicarboxylate (Ni−BDC) MOF nanosheets can be fabricated with the assistance of supercritical (SC) CO2 in a pure aqueous system. Detailed experimental evidence reveals that the SC CO2 molecule can exchange with the lattice-coordinated H2O molecules, side-on coordinate with the metal Ni1 sites on the Ni−BDC surface, and finally break the interlayer hydrogen bond to exfoliate the bulk Ni−BDC into a 2D MOF. More importantly, a thin SC CO2 layer building up at the water−Ni−BDC interfaces can transform the pristine hydrophilic interface into a super-hydrophobic one. This super-hydrophobic layer at the water-MOF interface can effectively prevent dissociation, thus promoting the stability of Ni−BDC in aqueous system. 相似文献
34.
Three coordination polymers, namely, {[Cu2(HMOPhIDC)(4,4′-bipy)]}n (H3MOPhIDC = 2-(3-methoxyphenyl)-1H-imidazole-4,5-dicarboxylic acid) (1), [Co(HDMOPhIDC)(phen)]n (H3DMOPhIDC = 2-(3,4-dimethoxyphenyl)-1H-imidazole-4,5-dicarboxylic acid) (2) and [Ni2(HDMOPhIDC)2(H2O)4]n (3) have been prepared under hydrothermal condition and characterised by elemental analyses, infrared spectroscopy and single-crystal X-ray diffraction. Each of the polymers 1–3 is a 1D column-like structure and displays a 3D supramolecular network via the π…π stacking or hydrogen bond interactions. Furthermore, fluorescence and UV–vis spectroscopic properties of the polymers have been studied. 相似文献
35.
Demetrios N. Nicolaides Konstantinos E. Litinas Ioannis Psaroulis Aristea Makri Spyros Adamopoulos 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2104-2111
Abstract Dimethyl (chromen-3-yl)-(dialkoxyphosphoryl)succinates are prepared from the reaction of 4-hydroxycoumarin with DMAD and P(OR)3. 4-Hydroxy-1-methylquinolinone reacts with DMAD and P(OEt)3 to give dimethyl (quinoline-3-yl)-(diethoxyphosphoryl)-succinate. GRAPHICAL ABSTRACT 相似文献
36.
本文首先合成了多功能有机桥联配体:2-(对溴)苯基-4,5-咪唑二羧酸(p-BrPhH3IDC),使之与Ni(Ⅱ)在溶剂热条件下自组装,得到了一个二维配位聚合物{[Ni(p-BrPhH2IDC)2].2H2O}n(1)。采用红外光谱、元素分析以及X-ray单晶衍射表征了这个配合物的分子结构。结果表明:H3BrPhIDC配体表现出比较强的配位能力,这和通过量子化学计算给出的预测一致。研究了此配聚物在空气气氛下的热稳定性以及采用变温磁化率研究了在2.0~300 K范围内的磁性质。结果表明:在配合物1中,相邻镍离子间存在着弱的反铁磁偶合作用。 相似文献
37.
氧化双[三(2-甲基-2-苯基)丙基]锡分别与酒石酸、乙二酸反应,合成了2个二[三(2-甲基-2-苯基)丙基锡]二元羧酸酯[CH(OH)COOSn(CH2Me2CPh)3]2(1)和[COOSn(CH2Me2CPh)3]2·2MeOH(1)。经元素分析、IR、1H和13C-NMR以及X-射线单晶衍射表征结构。化合物中,锡原子均为畸变四面体构型,分子间通过O-H…O和C-H…O氢键作用,化合物1和2分别形成一维无限链结构和二维网状结构。在空气氛下化合物有较好的热稳定性;除草活性结果表明,化合物1和2对马齿苋、稗草、反枝苋、决明子、狗尾草和藜等农作物杂草显示出一定的生物活性,特别是对马齿苋、狗尾草和藜的茎和根的作用较明显,化合物2在25mg·L-1的较低浓度下选择性、高效地抑制马齿苋的茎和根的生长,为马齿苋的除草剂研究提供了一种方法。 相似文献
38.
Mohammed-Abdul Raheem 《合成通讯》2013,43(2):260-267
7-Oxanorbornadienes are valuable synthetic intermediates as they can serve as general templates to create highly substituted ring systems. However, to date, only very few C1-substituted 7-oxanorbornadienes have been synthesized and can be found in the literature. In this article, synthesis of some C1-substituted 7-oxanorbornadienes was achieved by the Diels–Alder reaction between 2-substituted furans and dimethylacetylene dicarboxylate. Moderate to good yields (13–85%) of the Diels–Alder reactions were observed. These C1-substituted 7-oxanorbornadienes will find applications as valuable synthetic intermediates and are useful in the studies of transition-metal-catalyzed reactions. 相似文献
39.
Two metal‐organic coordination polymers with one‐dimensional infinite chain motif, [Cd(bqdc)(phen)2]n ( 1 ) and [Co(bqdc)(phen)(H2O)2]n ( 2 ) (H2bqdc = 2,2′‐biquinoline‐4,4′‐dicarboxylic acid, phen = 1,10‐phenanthroline), have been synthesized under similar solv/hydrothermal conditions and fully structural characterized by elemental analysis, IR, and single‐crystal X‐ray crystallography. Their thermal stability and photoluminescence properties were further investigated by TG‐DTA and fluorescence spectra. In both complexes, the adjacent metal ions (CdII for 1 and CoII for 2 ) are linked together by dicarboxylate groups of bqdc dianions in chelating bidentate and monodentate modes, respectively, generating a zigzag chain for 1 and linear chain for 2 . The relatively higher thermal stability up to 324 °C for 1 and strong fluorescence emissions jointly suggest that they are good candidates for luminescent materials. 相似文献
40.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(8):645-651
Careful choice of the organic ligands is one of the most important parameters in the rational design and synthesis of coordination polymers. Aromatic polycarboxylates have been widely used in the preparation of metal–organic polymers since they can utilize various coordination modes to form diverse structures and can act as hydrogen‐bond acceptors and donors in the assembly of supramolecular structures. Nitrogen‐heterocyclic organic compounds have also been used extensively as ligands for the construction of polymers with interesting structures. In the polymers catena‐poly[[[diaquabis{2‐[(1H‐imidazol‐1‐yl)methyl]‐6‐methyl‐1H‐benzimidazole‐κN 3}cobalt(II)]‐μ2‐benzene‐1,4‐dicarboxylato‐κ2O 1:O 4] dihydrate], {[Co(C8H4O4)(C12H11N4)2(H2O)2]·2H2O}n , (I), and catena‐poly[[[diaquabis{2‐[(1H‐imidazol‐1‐yl)methyl]‐6‐methyl‐1H‐benzimidazole‐κN 3}nickel(II)]‐μ2‐benzene‐1,4‐dicarboxylato‐κ2O 1:O 4] dihydrate], {[Ni(C8H4O4)(C12H11N4)2(H2O)2]·2H2O}n , (II), the CoII or NiII ion lies on an inversion centre and exhibits a slightly distorted octahedral coordination geometry, coordinated by two N atoms from two imidazole rings and four O atoms from two monodentate carboxylate groups and two water molecules. The dicarboxylate ligands bridge metal ions forming a polymeric chain. The 2‐[(1H‐imidazol‐1‐yl)methyl]‐6‐methyl‐1H‐benzimidazole ligands coordinate to the CoII or NiII centres in monodentate modes through an imidazole N atom and are pendant on opposite sides of the main chain. The two structures are isomorphous. In the crystal, the one‐dimensional chains are further connected through O—H…O, O—H…N and N—H…O hydrogen bonds, leading to a three‐dimensional supramolecular architecture. In addition, the IR spectroscopic properties, PXRD patterns, thermogravimetric behaviours and fluorescence properties of both polymers have been investigated. 相似文献