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81.
Josep L. Acero Sanchez Olivier Y. F. Henry Teresa Mairal Nadja Laddach Anders Nygren Siegfried Hauch Jasmin Fetisch Ciara K. O’Sullivan 《Analytical and bioanalytical chemistry》2010,397(6):2325-2334
An enzyme-linked oligonucleotide assay (ELONA) for quantification of mRNA expression of five genes involved in breast cancer,
extracted from isolated rare tumour cells and amplified by multiplex ligation-dependent probe amplification (MLPA) is presented.
In MLPA, a multiplex oligonucleotide ligation assay is combined with a PCR reaction in which all ligation products are amplified
by use of a single primer pair. Biotinylated probes complementary to each of the target sequences were immobilised on the
surface of a streptavidin-coated microtitre plate and exposed to single-stranded MLPA products. A universal reporting probe
sequence modified with horseradish peroxidase (URP–HRP) and complementary to a universal primer used during the MLPA step
was further added to the surface-bound duplex as a reporter probe. Simultaneous addition of anchoring probe and target, followed
by addition of reporter probe, rather than sequential addition, was achieved with no significant effect on sensitivity and
limits of detection, but considerably reduced the required assay time. Detection limits as low as 20 pmol L−1, with an overall assay time of 95 min could be achieved with negligible cross-reactivity between probes and non-specific
targets present in the MLPA-PCR product. The same MLPA-PCR product was analysed using capillary electrophoresis, the technique
typically used for analysis of MLPA products, and good correlation was observed. The assay presented is easy to carry out,
relatively inexpensive, rapid, does not require sophisticated instrumentation, and enables quantitative analysis, making it
very promising for the analysis of MLPA products. 相似文献
82.
The trans diesters of 1,4-cyclohexanediol with a number of acetic acid analogues, CX3COOH, of varying steric hindrance and polarity (CX3 = Me, Et, iso-Pr, tert-Bu, CF3, CH2Cl, CHCl2, CCl3, CH2Br, CHBr2, CBr3) were synthesized, and the axial,axial/equatorial,equatorial conformational equilibria were studied by low-temperature 1H NMR spectroscopy in CD2Cl2. The structures and relative energies of the axial,axial and equatorial,equatorial conformers were calculated at both the MP2/6-311G* and the MP2/6-311+G* levels of theory, and it was only by including diffuse functions that a good correlation of deltaG(o)calcd vs deltaG(o)exptl could be obtained. Both the structures and the energy differences of the axial,axial and equatorial,equatorial conformers are discussed with respect to the established models of conformational analysis, viz., steric 1,3-diaxial and hyperconjugative interactions. Interestingly, the hyperconjugative interactions sigma(C-C)/sigma(C-H) --> sigma*(C-O), together with a steric effect which also destabilizes the equatorial,equatorial conformers on increasing bulk of the substituents, proved to dominate the position of the conformational equilibria. In addition, the preference of the axial,axial conformers with respect to their equatorial,equatorial analogues was greater than expected from the conformational energies of the corresponding substituents in the monosubstituted cyclohexyl esters. The reason for this very interesting and unexpected result is also discussed. 相似文献
83.
Nadja Noormofidi 《European Polymer Journal》2010,46(4):694-701
Two norbornene derivatives bearing phenantroimidazole dyes, namely endo/exo-11-(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenoxy) undecylbicyclo[2.2.1] hept-5-ene-2-carboxylat (5) and 11-(4-(1-Methyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenoxy) undecylbicyclo[2.2.1]hept-5-ene-2-carboxylate (6) were synthesized. 5 and 6 were used to prepare statistical copolymers with endo,exo-bicyclo[2.2.1.]hept-2-ene-5,6-dicarboxylic acid dimethylester (7) via ring opening metathesis polymerization. The photophysical properties of the monomers and polymers and to what extent polymerization and substitution patterns influence the photophysical properties were investigated. Furthermore, the optical response upon addition of acid was investigated. The emission of monomer 5 shows a small bathochromic shift of 13 nm upon protonation while the emission of the resultant polymer poly5/7 exhibits a large red shift of 62 nm. In contrast, the according methylated monomer 6 and the resulting polymer poly6/7 gave similar absorption and emission characteristics. The differences were attributed to an increased tendency of the non-methylated dyes to interact when brought in close proximity in the polymer. 相似文献
84.
Buchner N Krumbein A Rohn S Kroh LW 《Rapid communications in mass spectrometry : RCM》2006,20(21):3229-3235
The current research involves the study of the thermal treatment of quercetin and rutin in an aqueous model system (cooking). These substances were heated and their degradation was followed by high-performance liquid chromatography/diode-array detection (HPLC/DAD). The influence of pH and the involvement of oxygen in the degradation were studied. HPLC/electrospray ionization multi-stage mass spectrometry (ESI-MS(n)) was used for the structural characterization of the compounds produced. The influence of the degradation of the phenolic compounds on their antioxidant properties was elucidated by a electron spin resonance (ESR) spectrometry study of the reaction samples mixed with the stabilized radical, Fremy's salt. Strong degradation of the model substances took place under weak basic and oxidative conditions. Quercetin showed the most intense degradation. Protocatechuic acid could be identified as a cleavage reaction product by analyzing its retention time and molar mass during the degradation of quercetin. The structure of a second cleavage product could be identified on the basis of ESI-MS(n) fragmentation data. Also, several structures for reaction products of oxidized quercetin are suggested. The ESR analysis showed a decrease in the antioxidant activity of the reaction samples after heat treatment in aqueous solution. 相似文献
85.
JPC – Journal of Planar Chromatography – Modern TLC - Cholesterol is an essential component of mammalian cells, but its role in cancer is unclear. We have determined the total... 相似文献
86.
Lucien N. Lameijer Simon Budzak Nadja A. Simeth Mickel J. Hansen Ben L. Feringa Denis Jacquemin Wiktor Szymanski 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(48):21847-21854
Molecular photoswitches enable reversible external control of biological systems, nanomachines, and smart materials. Their development is driven by the need for low energy (green-red-NIR) light switching, to allow non-invasive operation with deep tissue penetration. The lack of clear design principles for the adaptation and optimization of such systems limits further applications. Here we provide a design rulebook for tetra-ortho-chloroazobenzenes, an emerging class of visible-light-responsive photochromes, by elucidating the role that substituents play in defining their key characteristics: absorption spectra, band overlap, photoswitching efficiencies, and half-lives of the unstable cis isomers. This is achieved through joint photochemical and theoretical analyses of a representative library of molecules featuring substituents of varying electronic nature. A set of guidelines is presented that enables tuning of properties to the desired application through informed photochrome engineering. 相似文献
87.
Nadja Frömmgen Dimiter L. Balabanski Mark L. Bissell Jacek Bieroń Klaus Blaum Bradley Cheal Kieran Flanagan Stephan Fritzsche Christopher Geppert Michael Hammen Magdalena Kowalska Kim Kreim Andreas Krieger Rainer Neugart Gerda Neyens Mustafa M. Rajabali Wilfried Nörtershäuser Jasna Papuga Deyan T. Yordanov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2015,69(6):164
88.
89.
90.
Koller FO Haiser K Huber M Schrader TE Regner N Schreier WJ Zinth W 《Optics letters》2007,32(22):3339-3341
The widely used setup for the generation of femtosecond infrared (IR) pulses based on parametric amplifiers (OPAs) and difference frequency mixing (DFM) is extended to produce tunable narrowband mid-IR pulses. The insertion of pairs of silicon prisms after the OPA induces adjustable chirp, which leads to the generation of narrowband pulses in the DFM stage. Rapid tunability of the mid-IR wavelength via a computer-controllable actuator can be achieved in a range of approximately 200 cm(-1) at a bandwidth of the IR-pulses between approximately 15 and approximately 50 cm(-1) and pulse energies up to 0.4 microJ. The narrowband mid-IR pulses are well suited for 2D IR spectroscopy. 相似文献