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41.
1,3-共轭烯炔不仅是有机合成的重要中间体, 许多天然产物和具有生理活性的化合物的核心骨架都含有共轭烯炔单元, 在已有的共轭烯炔的合成方法中钯铜共催化的烯基卤与端炔的Sonogashira 偶联反应占据了统治地位. 炔卤化合物是一种独特有趣的有机分子, 它既能参与类似于端炔的偶联反应, 又具有卤苯的过渡金属氧化加成的性能, 这些特点使炔卤在构建复杂有机分子中起着重要的作用. 我们以Pd(OAc)2为催化剂, K2CO3为碱, 在DMF溶剂中实现了末端烯和炔基溴的交叉偶联反应高区域和立体选择性地合成1,3-共轭烯炔, 考察了催化剂的种类、碱的种类和温度对反应的影响. 研究结果表明: 5 mol% Pd(OAc)2, 2.5 equiv. K2CO3, 在DMF溶剂中, 不需要任何配体和添加剂, 炔基溴与苯乙烯衍生物于80 ℃, 与贫电子烯烃于室温反应2 h可以高产率得到所需产物, 所有化合物的结构用IR, 1H NMR, 13C NMR, MS, 高分辨质谱等方法进行了表征, 该偶联反应合成途径简捷、反应条件温和, 可为共轭烯炔化合物合成提供简便的途径. 相似文献
42.
苯基修饰的疏水微孔二氧化硅膜的制备与表征 总被引:2,自引:0,他引:2
采用苯基三乙氧基硅烷(PTES)和正硅酸乙酯(TEOS)作为前驱体,通过溶胶-凝胶法制备了苯基修饰的SiO2膜材料。利用扫描电镜、N2吸附、视频光学接触角测量仪、热重分析、红外光谱等测试手段对膜的孔结构以及疏水性能进行了表征,最后还研究了修饰后膜材料在室温条件下的单组份气体渗透和分离性能。结果表明,随着PTES加入量的增大,膜材料的疏水性逐渐增强,当PTES/TEOS和H2O/TEOS的化学计量比分别达到0.6和9.6时,膜材料对水的接触角达到115±0.5°,仍保持良好的微孔结构,其孔体积为0.17cm3/g,孔径为0.4-0.5nm。室温下氢气在修饰后SiO2膜的输运既遵循发生在微孔孔道的表面扩散机理也遵循发生在较大孔道或者微缺陷的努森扩散机理,膜材料的H2渗透率达到1.49×10-6mol?m-2?Pa-1?s-1,H2/CO2 和H2/SF6的理想分离系数分别达到4.64和365.59 相似文献
43.
44.
José M. Cid 《Tetrahedron letters》2004,45(6):1133-1136
A method for the selective α-monoallylation of phenyl ketones and benzocycloalkanones with allyl alcohol under microwave irradation is described. The corresponding α-allyl ketones are obtained in moderate to good yields with only minor quantities of diallylation by-products. 相似文献
45.
46.
《无机化学与普通化学杂志》2018,644(12-13):585-589
The reaction of Hppko (Hppko = phenyl 2‐pyridyl ketone oxime) and CoCl2 · 6H2O in the CH3OH solvent with the presence of triethylamine (NEt3) at room temperature and the exposure to air resulted in the formation of a new pentanuclear, mixed‐valence cobalt complex with the molecular formula [{CoII(CH3O)3}2{CoIII3(μ3‐O)(ppko)3}Cl2]. X‐ray single crystal analysis displays a trigonal bipyramid configuration with the terminal two CoII ions wrapping an triangle [CoIII3O]7+ core. The intermolecular C–H ··· O and C–H ··· Cl interactions form a 2D network framework. The analysis of magnetic susceptibility revealed the dominant antiferromagnetic interactions and strong orbital contribution of CoII ions. 相似文献
47.
Whei Oh Lin Maria Cecilia Bastos Vieira de Souza 《Monatshefte für Chemie / Chemical Monthly》1981,112(2):253-258
A series of short chain acyclic crown ethers such as (1,2), (1,3), (1,4)-phenylenediethers and some symmetric or assymmetrico-substituted phenyl ethers were prepared. The complexation studies of these compounds were carried out by a) direct UV titration method, b) picrate extraction method and c) isolation of crystalline complex.Taken in part from the master's thesis ofMaria Cecilia Bastos Vieira de Souza, Instituto Militar de Engenharia, 1978. 相似文献
48.
Tat''yana V. Baukova Lyudmila G. Kuz''mina Natal''ya A. Oleinikova Dmitrii A. Lemenovskii Aleksander L. Blumenfel''d 《Journal of organometallic chemistry》1997,530(1-2):27-38
Two organogold derivatives of diphenylmethane and diphenylethane, Ph3PAu(o-C6H4)CH2(C6H4-o)AuPPh3 (1) and Ph3PAu(o-C6H4)(CH2)2(C6H4-o)AuPPh3 (2), have been synthesized by the reaction of ClAuPPh3 with Li(o-C6H4)CH2(C6H4-o)Li and Li(o-C6H4)(CH2)2(C6H4-o)Li respectively. The interaction of 1 with dppe results in the replacement of the two PPh3 groups to give a macrocyclic compound (3) that includes an Au Au bond. Compounds 1 and 2 react with one or two equivalents of [Ph3PAu]BF4 to form new types of cationic complex [CH2(C6H4-o)2(AuPPh3)3]BF4 (4), [CH2(C6H4-o)2(AuPPh3)4](BF4)2 (5), and [(CH2)2(C6H4-o)2(AuPPh3)4](BF4)2 (6). Complexes 1–6 have been characterized by X-ray diffraction studies, FAB MS, and IR as well as by 1H and 31P NMR spectroscopy. A complicated system of Au H-C agostic interactions, involving the bridging alkyl groups (—CH2— and CH2-CH2—) of diphenylmethane and diphenylethane ligands, has been found to occur in complexes 1–3 and 6. 相似文献
49.
Jeremy N. Harvey Massimiliano Aschi Helmut Schwarz Wolfram Koch 《Theoretical chemistry accounts》1998,99(2):95-99
The phenyl cation is known to have two low-energy minima, corresponding to 1
A
1 and 3
B
1 states, the first of which is more stable by ca. 25 kcal/mol. The minimum energy crossing point between these two surfaces,
located at various levels including a hybrid method first described here, lies just above the minimum of the triplet, 0.12
kcal/mol at the CCSD(T)/cc-pVDZ//B3LYP/SV level, and there is significant spin-orbit coupling between the surfaces at this
point. On the basis of these results, the lifetime of the triplet is expected to be very short.
Received: 24 October 1997 / Accepted: 25 November 1997 相似文献
50.
Sophie KleinJing H Zhang Michel HollerJean-Marc Weibel Patrick Pale 《Tetrahedron》2003,59(49):9793-9802
Ethynyl oxiranes can be deprotonated with nBuLi in THF and trapped with various electrophiles, providing a stereoselective access to trisubstituted oxiranes. Alkyl iodides and aldehydes react readily with the ethynyloxiranyl anions but not sulfonyl derivatives. Mechanistic investigations highlighted the stabilizing role of the ethynyl group, the localization of the anion and the coordinating role of the oxirane oxygen atom during deprotonation. 相似文献