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排序方式: 共有96条查询结果,搜索用时 31 毫秒
1.
Tuija Jokinen Dr. Mikko Sipilä Stefanie Richters Prof. Veli‐Matti Kerminen Dr. Pauli Paasonen Dr. Frank Stratmann Dr. Douglas Worsnop Prof. Markku Kulmala Dr. Mikael Ehn Prof. Hartmut Herrmann Dr. Torsten Berndt 《Angewandte Chemie (International ed. in English)》2014,53(52):14596-14600
Gas‐phase oxidation routes of biogenic emissions, mainly isoprene and monoterpenes, in the atmosphere are still the subject of intensive research with special attention being paid to the formation of aerosol constituents. This laboratory study shows that the most abundant monoterpenes (limonene and α‐pinene) form highly oxidized RO2 radicals with up to 12 O atoms, along with related closed‐shell products, within a few seconds after the initial attack of ozone or OH radicals. The overall process, an intramolecular ROO→QOOH reaction and subsequent O2 addition generating a next R′OO radical, is similar to the well‐known autoxidation processes in the liquid phase (QOOH stands for a hydroperoxyalkyl radical). Field measurements show the relevance of this process to atmospheric chemistry. Thus, the well‐known reaction principle of autoxidation is also applicable to the atmospheric gas‐phase oxidation of hydrocarbons leading to extremely low‐volatility products which contribute to organic aerosol mass and hence influence the aerosol–cloud–climate system. 相似文献
2.
Veli SHAKHMUROV 《数学年刊B辑(英文版)》2011,32(5):749-770
The free boundary value problems for elliptic differential-operator equations are studied. Several conditions for the uniform
maximal regularity with respect to boundary parameters and the Fredholmness in abstract L
p
-spaces are given. In application, the nonlocal free boundary problems for finite or infinite systems of elliptic and anisotropic
type equations are studied. 相似文献
3.
Hany Nasef Valerio Beni Veli C. Őzalp Ciara K. O’Sullivan 《Analytical and bioanalytical chemistry》2010,396(7):2565-2574
Cystic fibrosis is one of the most common genetically inherited diseases in northern Europe, with the DF508 mutation being
the most common, and among the Caucasian population being responsible for almost 70% of cases. In this work, we report on
the use of thermally modulated electrochemical impedance spectroscopy for the discrimination of the DF508 mutation from the
wild-type sequence. DNA probes (15 and 21 bases long) were immobilised on the surface of gold electrodes and the variation
of the charge-transfer resistance was monitored as a function of hybridisation. Two sets of targets were used in this work:
synthetic 15-mer sequences and two single-stranded synthetic analogues of PCR products 82 (mutant) and 85 (wild type) bases
long. Hybridisation with short targets resulted in very sequence specific charge-transfer-resistance variation with a discrimination
factor at room temperature between fully complementary and mismatched sequences of approximately fivefold. However, in the
case of the single-stranded synthetic PCR product analogues, a lower discrimination factor was recorded (1.5-fold). The effect
of temperature was investigated to improve discrimination and the use of a posthybridisation wash at elevated temperature
resulted in a fivefold improvement in the discrimination factor. Using an electrode array with probes immobilised against
each of the mutant and wild-type sequences, we achieved an unequivocal detection of the DF508 mutation. 相似文献
4.
Lenka Škantárová Andrej Oriňák Renáta Oriňáková Monika Jerigová Monika Stupavská Dušan Velič 《Surface and interface analysis : SIA》2013,45(8):1266-1272
Present article deals with functionality of silver nanostructured surfaces prepared by potentiostatic electrochemical deposition on the paraffin impregnated graphite electrode as template‐free substrates. The effect of the electrodeposition conditions on two silver surface functions: analytical signal enhancement in Surface‐enhanced Raman spectroscopy and pre‐ionization function, applied in secondary ion mass spectrometry (SIMS) is reported. Functional silver nanostructured substrate was prepared at a potential ?850 mV with a deposition duration of 20 min. Analytical signal enhancement factors of 3.2 ×105 for Raman peak at 649 cm?1, 3.0×105 for peak at 810 cm?1 and 2.7×105 for peak at 1539 cm?1 were determined for Rhodamine 6G at deposited surface. Slight pre‐ionization effect has been observed in SIMS, and 1.2×105 fold signal enhancement was established for fragment of Rhodamine 6G with m/z 429 (M‐CH3‐Cl). Electrochemical preparation of nanostructures represents a step towards surface integration directly into miniaturized systems and sensors. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
6.
Veli B. Shakhmurov 《中国科学A辑(英文版)》2008,51(7):1215-1231
The unique continuation theorems for the anisotropic partial differential-operator equations with variable coeffcients in Banach-valued Lp-spaces are studied.To obtain the uniform maximal regularity and the Carleman type estimates for parameter depended differential-operator equations,the suffcient conditions are founded.By using these facts,the unique continuation properties are established.In the application part,the unique continuation properties and Carleman estimates for finite or infinite systems of quasielliptic partial differential equations are studied. 相似文献
7.
Veli B. Shakhmurov 《Journal of Mathematical Analysis and Applications》2007,327(2):1182-1201
The nonlocal boundary value problems for anisotropic partial differential-operator equations with a dependent coefficients are studied. The principal parts of the appropriate generated differential operators are nonself-adjoint. Several conditions for the maximal regularity and the fredholmness in Banach-valued Lp-spaces of these problems are given. These results permit us to establish that the inverse of corresponding differential operators belongs to Schatten q-class. Some spectral properties of the operators are investigated. In applications, the nonlocal BVP's for quasielliptic partial differential equations and for systems of quasielliptic equations on cylindrical domain are studied. 相似文献
8.
New bidentate N-(2,6-di-phenyl-1-hydroxyphenyl) salicylaldimines bearing X = H and 3,5-di-t-butyl substituents on the salicylaldehyde ring, L
x
H, and their copper(II) complexes, Cu(L
x
)2, have been synthesized and characterized by i.r., u.v./vis., 1H-n.m.r., 13C-n.m.r., e.s.r. spectroscopy and magnetic susceptibility measurements. E.s.r. study has shown that chemical oxidation of Cu(L
x
)2 with PbO2 produces ligand-centered CuII-phenoxyl radical species. The complexes are easily reduced with PPh3
via intramolecular electron transfer from ligand to copper(II) to give unstable radical intermediates, which in time are converted to another stable secondary radical species. The analysis of e.s.r. spectra of Cu(L
x
)2 and generated radical intermediates are presented. 相似文献
9.
The preparation and spectroscopic characterization of a series of new bis[N-(2,6-di-t-butyl-1-hydroxyphenyl)salicylaldiminato]nickel(II) complexes, [Ni(LX)2], bearing one or two OH and MeO substituents on the salicylaldehyde moiety, as well as radical species generated from these compounds by the oxidation with PbO2, are reported. The [Ni(LX)2] chelates, which appear to be tetrahedral in the solid state and in dioxane solution, are converted into a square-planar configuration in non-donor solvents. The OH-substituted complexes, unlike their MeO analogues, form six-coordinate adducts in pyridine, DMF and DMSO. These new compounds, unlike their analogues with electron-withdrawing substituents (Cl, Br, NO2), are easily oxidized by PbO2 to produce NiII-stabilized phenoxy radicals in which the unpaired electrons are delocalized over the ligand and do not couple with the second radical center. No e.s.r. signals were observed that could be attributed to a M = ±2 transition of the triplet state biradicals. 相似文献
10.
A new N-TEMPO-3,5-di-tert-butylsalicylaldimine radical (1) has been synthesized and characterized by single crystal X-ray diffraction, elemental analysis, IR, UV–vis, and EPR spectroscopy and temperature dependent magnetic susceptibility. X-ray diffraction revealed that H-atoms of γ-CH in TEMPO and CH3 in salicylaldimine moieties, are located in close contact with the neighboring N–O radical group in crystal 1. The temperature dependence of the magnetic susceptibility (χm) of 1 has been fitted by the Curie–Weiss law with θ = −0.3 K within 10–300 K, suggesting the presence of a weak intermolecular antiferromagnetic interaction between radical centers at T < 10 K. It has been demonstrated that radical 1 possesses crystal structure involving co-existence of antiferromagnetic and ferromagnetic interactions through C–H?O–N contacts of γ-CH and tBu groups hydrogen atoms, in which the former path dominates over the latter. 相似文献