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51.
在水热条件下,通过使用羧酸和螯合配体得到了一个系列的四核镧系簇合物,即[Ln4(mnba)12(tzp)2(H2O)2](Ln=Gd(1),Tb(2),Er(3);Hmnba=间硝基苯甲酸;tzp=2-(1H-1,2,4-三唑-3-基)吡啶))。这3个化合物是同构的,且具有线性的四核簇结构。磁性研究表明,化合物1和3中簇内镧系离子之间是弱铁磁耦合的,但化合物2中铽离子之间是弱的反铁磁相互作用和(或)铽离子激发的斯塔克能级的去布居。化合物1具有较大的磁热效应(-ΔSmmax=20.6 J·kg-1·k-1)。交流磁化率测试表明化合物3展现出频率和温度依赖的虚部信号,这是慢磁弛豫的典型特征,原因是铒离子的强各向异性和铁磁耦合的存在。 相似文献
52.
We report the efficient preparation of furo[2,3‐d]pyridazin‐4(5H)‐one and its N‐substituted derivatives starting from methyl 2‐methylfuran‐3‐carboxylate. The Me group was converted to the aldehyde group, which was then condensed with hydrazine derivatives. Then, the ester functionalities were hydrolyzed to the corresponding acids, followed by treatment with SOCl2 to give N‐substituted furopyridazinone derivatives. 相似文献
53.
A new series of metal complex carboxylates(MCC)made of [Co(en)3]3+(MC)and either 2,6-naphthalenedicarboxylic(NDC)or 4,4-biphenyldicarboxylic(BPDC)were synthesized and structurally characterized.The four new compounds have a general formula(MC)2(C)3·n(guest)with the guests of dimethylformamide(DMF)and dimethyl sulfoxide(DMSO)and water.All the structures represent a pillared-layer type,where the layer consists of MC cations,carboxylate anions or water molecules via a large number of hydrogen bonds.The layers are pillared by the organic residues of NDC or BPDC,resulting in the inclusion cavities where the guest molecules reside.Although their topological structures are similar,they crystallize in different crystal structures due to the rearrangement of pillars and hydrogen-bonded layers. 相似文献
54.
Li XB Zhang JY Wang YQ Song Y Gao EQ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(49):13883-13891
Three novel coordination polymers with azide and a bifunctional zwitterionic ligand bearing carboxylate and tetrazolate as bridging groups, [M(L)(N(3))]·xH(2)O [L=1-(carboxylatomethyl)-4-(5-tetrazolato)pyridinium, M=Cu (1, x=2), Ni (2, x=1), and Co (3, x=1)], have been synthesized and characterized by X-ray crystallography and magnetic measurements. The compounds consist of two-dimensional coordination layers in which uniform anionic chains with the unprecedented tricomponent (μ-azide)(μ-tetrazolate)(μ-carboxylate) bridges are cross-linked by cationic 1-methylenepyridinium spacers. The tricomponent bridges induce ferromagnetic interactions in all the compounds. Furthermore, this isostructural series of ferromagnetic-chain-based compounds has allowed us to observe distinct bulk properties that are dependent upon the natures of the different spin carriers: with the isotropic Cu(II) ion, 1 exhibits a paramagnetic phase of the ferromagnetic chains without long-range magnetic order above 2 K; with the weakly anisotropic Ni(II) ions, 2 displays antiferromagnetic ordering and field-induced metamagnetism without slow dynamic relaxation; and with Co(II), which has strong magnetic anisotropy due to first-order spin-orbital coupling, 3 exhibits magnetic hysteresis and slow magnetization dynamics typical of single-chain magnets. 相似文献
55.
The aromatic compounds p‐nitrobenzaldehyde, p‐hydroxybenzaldehyde, naphthalene, toluene, catechol, quinol, aniline and toluidine dissolved in aqueous acetic acid or aqueous medium were oxidized in quantitative to good yields by 50% H2O2 in the presence of traces of RuCl3 (~10?8 mol; substrate/catalyst ratio 1488:1 to 341 250:1). Conditions for highest yields, in the most economical way, were obtained. Higher catalyst concentrations decrease the yield. Oxidation in aromatic aldehydes is selective at the aldehydic group only. In the case of hydrocarbons, oxidation results in the introduction of a hydroxyl group with >85% (in the case of toluene) selectivity for the ortho position. Formation of low‐molecular‐weight polyaniline was reduced to 10%, along with 90% formation of higher molecular weight polyaniline. In this new, simple and economical method, which is environmentally safe and requires less time, oxo‐centered carboxylate species of ruthenium(III) in acetic acid medium and hydrated ruthenium(III) chloride in aqueous medium probably catalyze the oxidation. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
56.
Dainis Dakternieks Andrew Duthie Douglas R. Smyth Clynton P. D. Stapleton Edward R. T. Tiekink 《应用有机金属化学》2003,17(12):960-960
The tin atom in the title compound is in a skew‐trapezoidal bipyramidal geometry defined by two sets of nitrogen and oxygen donors derived from the carboxylate ligands and two carbon atoms from the tin‐bound cyclopentyl substituents; C? Sn? C 153.38(16)°. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
57.
Laijin Tian Yuxi Sun Bochu Qian Guoming Yang You Yu Zhicai Shang Xiaoliang Zheng 《应用有机金属化学》2005,19(10):1127-1131
A 1:1 reaction of triphenyltin chloride with potassium N‐[(3,5‐dibromo‐2‐hydroxyphenyl)methylene] valinate in benzene under reflux leads to the formation of a novel mixed organotin binuclear complex, Ph3Sn(HL)·Ph2SnL [L = 3,5‐Br2‐2‐OC6H2CH?NCH(i‐Pr)COO], by means of a facile phenyl–tin bond cleavage process. The X‐ray structure reveals that there are two distinct types of carboxylate coordination mode and trans‐O2SnC2N and trans‐O2SnC3 in distorted trigonal bipyramidal geometries. The complex displays good in vitro cytotoxicity and antibacterial activities. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
58.
含羧酸共生稀土光敏剂的低密度聚乙烯膜紫外光氧化降解 总被引:3,自引:0,他引:3
含羧酸共生稀土光敏剂的低密度聚乙烯膜紫外光氧化降解林宜超(福建省测试技术研究所福州350003)近年来,许多作者先后研究并开发出含硬脂酸铈(CeSt3)光敏剂的可控光降解低密度聚乙烯(LDPE)[1,2]、高密度聚乙烯[3]、聚丙烯[4]、聚苯乙烯... 相似文献
59.
Carolyn C. Woodroofe 《Tetrahedron》2005,61(12):3097-3105
Xanthene-based fluorophores such as fluorescein and rhodamine are typically prepared by acid-catalyzed condensation of the appropriate resorcinol or 3-aminophenol with phthalic anhydride. Condensation of substituted phthalic anhydride species results in functionalized fluorophores that are formed as mixed isomers. Crystallization approaches to isomer separation have been reported elsewhere for symmetric fluorescein carboxylates. We describe crystallization-based separation of protected fluorescein sulfonates and coupling conditions to form sulfonamides, precursors for carboxylate-substituted rhodamines, and precursors for asymmetrically substituted fluoresceins and rhodafluors. 相似文献