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排序方式: 共有107条查询结果,搜索用时 31 毫秒
81.
Dominique Nanty Marc Laurent Masood A. Khan Michael T. Ashby 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):35-36
Reaction of bis(2‐pyridylmethyl) ether with [Mo(CO)3(MeCN)3] in MeCN gives the title compound, [Mo(C12H12‐N2O)(CO)3], (I), as a yellow crystalline product. Compound (I) has been characterized by 1H NMR and IR spectroscopy, and single‐crystal X‐ray crystallography. In contrast with other examples of low‐valent early transition metal complexes of ethers, the ether linkage of (I) appears relatively inert. Nevertheless, the weak donor property of the ether ligand is evidenced by a trans effect manifested as a short Mo—CO bond length for the carbonyl ligand trans to the ether ligand. 相似文献
82.
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84.
We have studied the outer-sphere reduction of [Fe(CN)5(NO)]2- by several reagents including dithionite and have for the first time measured the IR spectra of [Fe(CN)5(NO)]3- and [Fe(CN)4(NO)]2- in aqueous media. The spectra of [Fe(CN)5(NO)]3- and [Fe(CN)4(NO)]2- are consistent with bent six-coordinate {MNO}7 and linear five-coordinate {MNO}7 species, respectively. We have measured the UV-visible and IR spectra that evolve after [Fe(CN)5(NO)]2- is reacted with thiolate. These spectra permit us to assign the molecular structure of the so-called "red product" as [Fe(CN)5(eta1-N-RSNO)]3-. We have followed the decomposition of the [Fe(CN)5(eta1-N-RSNO)]3- by IR. Importantly, there is a 1:1 correspondence between the disappearance of the [Fe(CN)5(eta1-N-RSNO)]3- and the formation of [Fe(CN)5(NO)]3-. Thus, we conclude under the conditions of this study, reduction of [Fe(CN)5(NO)]2- by thiolate takes place via a (dark) inner-sphere mechanism that yields [Fe(CN)5(NO)]3- via homolytic N-S bond cleavage. 相似文献
85.
Acrylamide: update on selected research activities conducted by the European food and drink industry
Taeymans D Andersson A Ashby P Blank I Gondé P van Eijck P Faivre V Lalljie SP Lingnert H Lindblom M Matissek R Müller D Stadler RH Studer A Silvani D Tallmadge D Thompson G Whitmore T Wood J Zyzak D 《Journal of AOAC International》2005,88(1):234-241
This paper reviews the progress made by the European food and drink industry (CIAA) on acrylamide with regard to analytical methods, mechanisms of formation, and mitigation research in the major food categories. It is an update on the first CIAA review paper, "A Review of Acrylamide: An Industry Perspective on Research, Analysis, Formation and Control." Initial difficulties with the establishment of reliable analytical methods, in most cases, have now been overcome, but challenges remain in terms of the need to develop simple and rapid test methods and certified reference materials. Many trials have been conducted under laboratory and experimental conditions in a variety of foods, and a number of possible measures have been identified to relatively lower the amounts of acrylamide in food. Promising applications were studied in reconstituted potato models by addition of amino acids or use of asparaginase. In bakery wares, predictive models have been established to determine the role of ammonium carbonate and invert sugar in acrylamide formation. Studies in several commercial foods showed that acrylamide is not stable over time in roasted and ground coffee. Some progress in relatively lowering acrylamide in certain food categories has been achieved, but at this stage can only be considered marginal. Any options that are chosen to reduce acrylamide in commercial products must be technologically feasible and must not adversely affect the quality and safety of the final product. 相似文献
86.
Energy dissipation chemical force microscopy has been used to analyze the dissipative properties of chemically similar regions of hydroxyl- and carboxyl-terminated SAMs on gold with a hydroxyl-terminated tip. Energy dissipation imaging quantitatively isolates dissipative interfacial interactions from topography, producing a significantly more informative image than phase imaging. Also, energy dissipation force curves probed the rheological properties of the tip-sample interaction. Viscosity of the confined water increased slightly over that of the bulk, and SAM deformation was found to have a longer retardation time than restructuring of interfacial ions and solvent during tip-sample contact. 相似文献
87.
Treatment of two isatin-3-imines, 3-isopropyIamino-1-methylindoline-2-one and 3-cyclohexylamino-1-methylindolin-2-one with sodium borohydride produced the fully-reduced anilines 2-isopropylamino-2-(2-methylaminophenyl) ethanol and 2-cyclohexylamino-2-(2-methylaminophenyl) ethanol, respectively. Reductive ring-opening of derivatives of isatin is not observed in related examples when either catalytic or lithium aluminum hydride reduction are employed and it is concluded that the present effect is dependant upon the softness of sodium borohydride as a reducing agent. 相似文献
88.
I. G. Gazarian G. A. Ashby R. N. F. Thorneley L. M. Lagrimini 《Applied biochemistry and biotechnology》1996,61(1-2):1-12
Anionic tobacco peroxidase (TOP) (mol wt 36 kDa, pI 3.5) was purified from transgenic tobacco plants with the yield of 60
mg/1 kg leaves. The enzyme exhibits unusual properties, i.e., Compound I is less reactive than Compound II. The enzyme was
investigated in oxidation of indole-3-acetic acid (IAA) oxidation by oxygen in the air. The aerobic steady-state spectral
studies reveal that Compound II is the key intermediate of the reaction mechanism. This was confirmed in the anaerobic stopped-flow
experiments. No reaction between the enzyme and IAA is observed under anaerobic conditions. The data obtained are interpreted
in terms of a ternary complex formation (ferric enzyme-IAA-oxygen) at the initiation step resulting in production of IAA radicals.
The latter interacts with the ferric enzyme and oxygen producing Compound II. The oxidative cycle involves the ferric enzyme
and Compound II, and is independent from the peroxidative one. 相似文献
89.
We demonstrate that the particle mediated interaction between a pendant water drop, covered by a latex particle monolayer, and a planar decane/water interface leads to bridging, analogous to flocculation in solid-stabilised emulsions. The results also provide information about the particle contact angle at the oil/water interface. 相似文献
90.
This report provides spectroscopic evidence to support a single electron transfer pathway to describe the reaction of metal hydrides with alkyl halides by direct EPR observation of the radical formed in the reaction. 相似文献