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排序方式: 共有173条查询结果,搜索用时 18 毫秒
1.
Dr. Jeanette E. Stok Dr. Sharon Chow Dr. Elizabeth H. Krenske Clementina Farfan Soto Csongor Matyas Prof. Raymond A. Poirier Prof. Craig M. Williams Prof. James J. De Voss 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4408-4412
The cytochromes P450 are hemoproteins that catalyze a range of oxidative C?H functionalization reactions, including aliphatic and aromatic hydroxylation. These transformations are important in a range of biological contexts, including biosynthesis and xenobiotic biodegradation. Much work has been carried out on the mechanism of aliphatic hydroxylation, implicating hydrogen atom abstraction, but aromatic hydroxylation is postulated to proceed differently. One mechanism invokes as the key intermediate an arene oxide (and/or its oxepin tautomer). Conclusive isolation of this intermediate has remained elusive and, currently, direct formation of phenols from a Meisenheimer intermediate is believed to be favored. We report here the identification of a P450 [P450cam (CYP101A1) and P450cin (CYP176A1)]‐generated arene oxide as a product of in vitro oxidation of tert‐butylbenzene. Computations (CBS‐QB3) predict that the arene oxide and oxepin have similar stabilities to other arene oxides/oxepins implicated (but not detected) in P450‐mediated transformations, suggesting that arene oxides can be unstable terminal products of P450‐catalyzed aromatic oxidation that can explain the origin of some observed metabolites. 相似文献
2.
Bert C. Lynn Mara Tsesarskaja Otto F. Schall Jeanette C. Hernandez Shigeru Watanabe Toshio Takahashi 《Supramolecular chemistry》2013,25(3-4):253-260
Abstract The interactions of macrocyclic polyethers with alkali and alkaline earth cations have been well studied and much about their chemistry is now well understood. Less well examined or comprehended are hydrogen bond interactions. A combination of ion selective electrode binding constant determination techniques and fast atom bombardment mass spectrometry are brought to bear on this problem. It is found that all-oxygen crown ethers and their derivatives exhibit quite different complexation behaviour with ammonium salts than do their various azacrown counterparts. 相似文献
3.
Eva C. Sonnenschein Marc Stierhof Stephan Goralczyk Floriane M. Vabre Leonie Pellissier Kine Østnes Hanssen Mercedes de la Cruz Caridad Díaz Peter de Witte Daniëlle Copmans Jeanette Hammer Andersen Espen Hansen Venke Kristoffersen José R. Tormo Rainer Ebel Bruce F. Milne Hai Deng Lone Gram Jioji N. Tabudravu 《Tetrahedron》2017,73(18):2633-2637
A new siderophore containing a 4,5-dihydroimidazole moiety was isolated from Pseudoalteromonas piscicida S2040 together with myxochelins A and B, alteramide A and its cycloaddition product, and bromo- and dibromoalterochromides. The structure of pseudochelin A was established by spectroscopic techniques including 2D NMR and MS/MS fragmentation data. In bioassays selected fractions of the crude extract of S2040 inhibited the opportunistic pathogen Pseudomonas aeruginosa. Pseudochelin A displayed siderophore activity in the chrome azurol S assay at concentrations higher than 50 μM, and showed weak activity against the fungus Aspergillus fumigatus, but did not display antibacterial, anti-inflammatory or anticonvulsant activity. 相似文献
4.
Priyanka Michael Espen Hansen Johan Isaksson Jeanette H. Andersen 《Natural product research》2020,34(14):2059-2064
AbstractThe new guanidine alkaloid Dendrobeaniamine A (1) was isolated from the organic extract of the Arctic marine bryozoan Dendrobeania murrayana. The chemical structure of 1 was elucidated by spectroscopic experiments, including 1D and 2D NMR and HRESIMS analysis. Compound 1 is a lipoamino acid, consisting of a C12 fatty acid anchored to the amino acid arginine. The bioactivity of 1 was evaluated using cellular and biochemical assays, but the compound did not show cytotoxic, antimicrobial, anti-inflammatory or antioxidant activities 相似文献
5.
Jeanette M. Torrescano-Alvarez Michele Curioni Xiaorong Zhou Peter Skeldon 《Surface and interface analysis : SIA》2019,51(12):1135-1143
The effects of applied current density, anodizing time, and electrolyte temperature on the cell and pore morphology of anodic films and the voltage-time response obtained during galvanostatic anodizing of AA2024-T3 alloy in sulphuric acid electrolytes have been studied. Scanning electron microscopy was employed to observe the film morphology. Sponge-like porous structure was promoted by anodizing at relatively low current density and high electrolyte temperature. In contrast, linear porous structure was favoured under the converse conditions. Intermediate conditions resulted in films containing either sequential layers of the 2 morphologies or a morphology incorporating features of the 2 types; such conditions were associated with anodizing voltages in the range 25 to 35 V. The reasons for the morphological differences are proposed to be due to interactions between film growth stresses and stresses arising from oxygen evolution on the development of the alumina cells. 相似文献
6.
Venke Kristoffersen Marte Jenssen Heba Raid Jawad Johan Isaksson Espen H. Hansen Teppo Rm Kine
. Hansen Jeanette Hammer Andersen 《Molecules (Basel, Switzerland)》2021,26(17)
The Lacinutrix genus was discovered in 2005 and includes 12 Gram-negative bacterial species. To the best of our knowledge, the secondary metabolite production potential of this genus has not been explored before, and examination of Lacinutrix species may reveal novel chemistry. As part of a screening project of Arctic marine bacteria, the Lacinutrix sp. strain M09B143 was cultivated, extracted, fractionated and tested for antibacterial and cytotoxic activities. One fraction had antibacterial activity and was subjected to mass spectrometry analysis, which revealed two compounds with elemental composition that did not match any known compounds in databases. This resulted in the identification and isolation of two novel isobranched lyso-ornithine lipids, whose structures were elucidated by mass spectrometry and NMR spectroscopy. Lyso-ornithine lipids consist of a 3-hydroxy fatty acid linked to the alpha amino group of an ornithine amino acid through an amide bond. The fatty acid chains were determined to be iso-C15:0 (1) and iso-C16:0 (2). Compound 1 was active against the Gram-positive S. agalactiae, while 2 showed cytotoxic activity against A2058 human melanoma cells. 相似文献
7.
Rate coefficients for the gas‐phase reaction of isoprene with nitrate radicals and with nitrogen dioxide were determined. A Teflon collapsible chamber with solid phase micro extraction (SPME) for sampling and gas chromatography with flame ionization detection (GC/FID) and a glass reactor with long‐path FTIR spectroscopy were used to study the NO3 radical reaction using the relative rate technique with trans‐2‐butene and 2‐buten‐1‐ol (crotyl alcohol) as reference compounds. The rate coefficients obtained are k(isoprene + NO3) = (5.3 ± 0.2) × 10?13 and k(isoprene + NO3) = (7.3 ± 0.9) × 10?13 for the reference compounds trans‐2‐butene and 2‐buten‐1‐ol, respectively. The NO2 reaction was studied using the glass reactor and FTIR spectroscopy under pseudo‐first‐order reaction conditions with both isoprene and NO2 in excess over the other reactant. The obtained rate coefficient was k(isoprene + NO2) = (1.15 ± 0.08) × 10?19. The apparent rate coefficient for the isoprene and NO2 reaction in air when NO2 decay was followed was (1.5 ± 0.2) × 10?19. The discrepancy is explained by the fast formation of peroxy nitrates. Nitro‐ and nitrito‐substituted isoprene and isoprene‐peroxynitrate were tentatively identified products from this reaction. All experiments were conducted at room temperature and at atmospheric pressure in nitrogen or synthetic air. All rate coefficients are in units of cm3 molecule?1 s?1, and the errors are three standard deviations from a linear least square analyses of the experimental data. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 37: 57–65, 2005 相似文献
8.
Michael?J.?Goldcamp Jeanette?A.?Krause Bauer Michael?J.?BaldwinEmail author 《Journal of chemical crystallography》2005,35(1):77-83
The ligand tris(1-propan-2-onyl oxime)amine (TRISOXH3) binds to zinc(II) acetate as a tridentate N3 donor, with a third oxime group remaining unbound and extending into the crystal lattice. The crystal structure shows a distorted trigonal bipyramidal geometry around the zinc center. An intramolecular hydrogen bonding interaction between a coordinated oxime donor and an oxygen of a bound acetate is observed. This structure is similar to that of a previously reported zinc(II) complex of a related bis(oxime)amine ligand. However, the structure of Zn(TRISOXH3)(OAc)2 is different in ligand coordination mode and metal coordination number from those of the previously reported complexes Ni(TRISOXH3)Cl2 or [Ni(TRISOXH3)(NO3)(H2O)]NO3. 相似文献
9.
Jaquay Cook Ashleigh Hicks Tyan Frazier David M. Kimari Theodore A. Budzichowski Jeanette A. Krause Bauer Santosh K. Mandal 《Journal of chemical crystallography》2003,33(5-6):481-489
The monodentate dithioformato complexes, fac-(CO)3(dppe)MnSC(S)H (1), fac- (CO)3(dppe)ReSC(S)H (2), fac-(CO)3(dppp)ReSC(S)H (3), and fac-(CO)3 (dppb)ReSC(S)H (4), where dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized from the treatment of the corresponding hydrides, fac-(CO)3 (P-P)MSC(S)H with CS2. Compounds 1–4 crystallize in the monoclinic crystal system: for 1, space group = P21/c, a = 15.3139(3) Å, b = 9.7297(4) Å, c = 19.0991(6) Å, = 105.928(1), V = 2736.5 Å3, Z = 4; for 2, space group = P21/c, a = 15.6395(8) Å, b = 9.8182(5) Å, c = 19.4153(11) Å, = 106.741(1), V = 2854.9(3) Å3, Z = 4; for 3, space group = P21/n, a = 11.3570(10) Å, b = 19.465(2) Å, c = 15.5702(14) Å, = 104.776(2), V = 3328.3(5) Å3, Z = 4; and for 4, space group = C2/c, a = 32.078(2) Å, b = 10.4741(6) Å, c = 19.0608(9) Å, = 94.315(2), V = 6386.1(6) Å3, Z = 8. 相似文献
10.
Dr. Benjamin A. Chalmers Hui Xing Sevan Houston Dr. Charlotte Clark Dr. Sussan Ghassabian Dr. Andy Kuo Benjamin Cao Andrea Reitsma Cody‐Ellen P. Murray Dr. Jeanette E. Stok Dr. Glen M. Boyle Carly J. Pierce Stuart W. Littler Prof. David A. Winkler Prof. Paul V. Bernhardt Dr. Cielo Pasay Prof. James J. De Voss Prof. James McCarthy Prof. Peter G. Parsons Prof. Gimme H. Walter Prof. Maree T. Smith Prof. Helen M. Cooper Prof. Susan K. Nilsson Dr. John Tsanaktsidis Dr. G. Paul Savage Prof. Craig M. Williams 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(28):8491-8491