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排序方式: 共有163条查询结果,搜索用时 46 毫秒
41.
Tadatomi Nishikubo Atsushi Kameyama Hiroto Kudo Kousuke Tsutsui 《Journal of polymer science. Part A, Polymer chemistry》2002,40(9):1293-1302
New photoreactive calixarene derivatives containing spiro ortho ester groups (calixarenes 3a–3c ) were synthesized by the reaction of 2‐bromomethyl‐1,4,6‐trioxaspiro[4.4]nonane with 2,8,14,20‐tetramethyl‐4,6,10,12,16,18,22,24‐octakis(carboxymethoxy)calix[4]resorcinarene, 5,11,17,23,29,35‐hexamethyl‐37,38,39,40,41,42‐hexakis(carboxymethoxy)calix[6]arene, and 5,11,17,23,29,35,41,47‐octa‐tert‐butyl‐49,50,51,52, 53,54,55,56‐octakis‐(carboxymethoxy)calix[8]arene, which were prepared by the reaction of C‐methylcalix[4]resorcinarene, p‐methylcalix[6]arene, and p‐tert‐butylcalix[8]arene, respectively. The thermal stability of the obtained calixarene derivatives containing spiro ortho ester groups was examined with thermogravimetric analysis, and it was found that these calixarene derivatives had good thermal stability. The photoinitiated cationic polymerization of spiro ortho ester groups in calixarene derivatives 3a–3c was examined with certain photoacid generators in the film state. Interestingly enough, the reaction of calixarene derivatives did not proceed with only photoirradiation; however, the reaction proceeded smoothly when the photoirradiation was followed by heating. Furthermore, calixarene 3a , composed of a C‐methylcalix[4]resorcinarene structure, showed the highest photochemical reactivity in this reaction system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1293–1302, 2002 相似文献
42.
Summary
N,N,N,N-Tetramethylisophthalthioamide (Hmpt) was cyclopalladated with PdCl2 in hot dimethylsulphoxide to give [PdCl(mpt)]. The structure was determined by X-ray analysis. The thioamide is metallated at C(2) to act as an S528-01C528-02S tridentate anionic ligand. There is appreciable steric repulsion between the benzene ring H(4, 6) and the dimethylamino groups. The hydrogens and the methyl groups mutually deviate from the coordination plane in opposite directions. The stability of the fused 5,5-membered chelate ring formed by the S528-03C528-04S ligand seems to overcome the steric hindrance. Derivatives were prepared by replacement of the chloride ion with iodide, diethyldithiocarbamate, 4-tert-butylpyridine, or tri-n-butylphosphine, and characterized spectroscopically. The S528-05C528-06S-fused chelate ring was maintained in these derivatives. 相似文献
43.
Matsuo Nonoyama 《Transition Metal Chemistry》1976,1(2):70-74
Summary Copper(II) and nickel(II) complexes of triazacycloalkanes (pqr-cy), with p, q, r = 2–6, have been prepared and characterized by means of electronic and i.r. spectroscopy, and by magnetic measurements. With nickel(II) mononuclear octahedral complexes [Ni(pgr-cy)2](CI04)2 are formed, but for copper(II) mononuclear octahedral complexes were obtained only for 222-cy and 223-cy. The other ligands gave copper(II) complexes of the type [Cu(pgr-cy)CI]CIO4, [Cu(pgr-cy)OH]ClO4, Or [Cu(pgr-cy)CI1/2OH1/2]ClO4. The hydroxy complexes have low magnetic moments and binuclear hydroxy bridged structures are proposed.Ligand names: e.g. p = q = r = 2 is 1,4,7-triazacvclononane 相似文献
44.
Conformational structures of solvated cobalt(II) ions in several amides and trimethyl phosphate (TMP) have been studied by the X-ray diffraction method using the isomorphous substitution technique. The amides used are formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), and N,N-dimethylpropioamide (DMPA). From the analysis of radial distribution functions around Co2+, the distances from Co2+ to each atom of coordinated solvent molecules were obtained and the coordination numbers were determined to be six, except for DMPA where four-coordinate species coexist. The Co—O bond distances are 2.09(1)–2.11(1) Å for six-coordinate species but is 1.96(2) Å for the four-coordinate species. In the amide solutions the Co—O—C bond angles are 126(3)° (FA), 123(2)° (NMF), 123(2)° (DMF), 134(3)° (DMA), and 137(4)–138(4)° (DMPA). The Co—O—C—N dihedral angles were also estimated to discuss the conformational distortion on the Co2+-amide interactions. For TMP solutions the Co—O—P angle was determined to be 150(4)°, and the conformational structure on the Co2+–TMP interaction is discussed. 相似文献
45.
Hiroaki Saito Kousuke Inoue Keiji Matsumoto Makoto Tadokoro Yukio Nakamura 《Journal of Cluster Science》1998,9(2):145-164
The oxidative addition reaction of 2,6-bis(bromomethyl)pyridine to Ru3(CO)12 gave scarcely soluble {Ru2Br2(-Q)(CO)4}
n
, 1, [Q=C5H3N-2-C(O)CH2-6-CH2] or a mixture of 1 and the mononuclear complex RuBr(Q)(CO)3, 2, [Q=C5H3N-2-C(O)CH2-6-CH2Br] according to the reactant's mole ratio. Further reactions of 1 with some N- and P-donor ligands (L) afforded readily soluble dinuclear complexes, Ru2(-Br)(-Q)Br(CO)
n
(L)
m
[n=4, m=1, L=PPh3
3a, or py 3b; n=3, m=2, L=PPh3
5a, or PPh2(o-tolyl) 5b]. In this paper, the characterization of these products by the elemental analyses and the spectroscopic methods are described. The X-ray crystal structures of Ru2(-Br) (-Q)Br(CO)4(PPh3)(MeOH), 4, which was obtained by crystallization of 3a from MeOH, and of 5a · (2CHCl
3
) are also described. Each of the metal atoms in 4 has a distorted octahedral coordination, while in 5a · (2CHCl
3
) one metal atom takes a distorted octahedral geometry and the other pseudooctahedral, which is completed by presenting a Ru ··· Br secondary bonding interaction. 相似文献
46.
47.
48.
Kobayashi T Yamaguchi T Ohta H Sunatsuki Y Kojima M Re N Nonoyama M Matsumoto N 《Chemical communications (Cambridge, England)》2006,(18):1950-1952
Two heterotrinuclear complexes, [Mn(II)(Ni(II)L)2].2CH3OH (where H3L = 1,1,1-tris(N-salicylideneaminomethyl)ethane) and [Fe(III)(Ni(II)L)2]NO3.C2H5OH, consisting of three face-sharing octahedra have been prepared; although these complexes have closely related structures and have the same 1-5/2-1 spin system, they show completely different magnetic interactions between the adjacent metal ions: ferromagnetic (Ni(II)-Mn(II)) and antiferromagnetic (Ni(II)-Fe(III)). 相似文献
49.
This paper describes the synthesis and properties of a new type of modified oligodeoxynucleotide containing a neutral but highly polarized squaryl group as a novel mimic of the phosphate group. A modified thymidine dimer derivative (TsqT) having a squaryldiamide linkage was synthesized in almost quantitative yield by a two-step substitution of diethyl squarate with 3'-amino-5'-O-(4,4'-dimethoxytrityl)-3'-deoxythymidine and 5'-amino-5'-deoxythymidine. The CD and UV studies of TsqT suggest that this dimer has basically a structure similar to that of TpT. The NMR studies of TsqT show a unique property, namely, that the squaryl group of TsqT is influenced by Mg2+ concentration. The ab initio calculations of TsqT showed a highly polarized structure resembling that of a phosphate group. This dimer structural motif was finally incorporated into oligodeoxynucleotides by use of the phosphoramidite approach. The hybridization affinity of these modified oligodeoxynucleotides for the complementary and mismatched oligodeoxynucleotides was studied in detail by using Tm experiments. Consequently, it turned out that in a matched duplex of 5'-d(CGCATsqTAGCC)-3'/5'-d(GGCTAATGCG)-3' the A-T base pairs at the modified site can be preserved, but instead thermal destabilization of the overall structure was observed. To estimate the structure of the duplex, two kinds of fluorescein chromophores (fluorescein (FL) and cyanine 3 (Cy3)) were introduced into the 5'-terminal site of 5'-d(GACGCATsqTAGCCGAT)-3' and 5'-d(ATCGGCTAATGCGTC)-3', respectively. The fluorescence resonance energy transfer experiments using these functionalized oligodeoxynucleotides suggest that the matched duplexes have a bent structure at the modified site. This conclusion was also strongly supported by computational MM and MD simulations. 相似文献
50.
Matsuo Nonoyama 《Transition Metal Chemistry》1987,12(1):1-3
Summary 2-(1-Pyrrolyl)pyrimidine(Hprpm) is cyclopalladated with lithium tetrachloropalladate in methanol in the presence of sodium acetate to give PdCl(prpm). This complex reacts with dimethylsulfoxide(dmso), pyridine(py). tri-n-butylphosphine(PBu3), tri-p-tolylphosphine(Ptol3), triphenylarsine(AsPh3), and acetylacetone(Hacac) to give PdCl(prpm)L (L=dmso, py, PBu3, Ptol3, AsPh3) and Pd(prpm)(acac), respectively. These complexes were characterized spectroscopically. The deprotonated ligand, prpm, is cyclopalladated and coordinated through pyrimidine-N and pyrrole-2C atoms to form a five membered palladaheterocycle. 相似文献