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Pintér G Batta G Horvath P Löki I Kurtan T Antus S Kéki S Zsuga M Nagy G Aradi J Gunda T Herczegh P 《Langmuir : the ACS journal of surfaces and colloids》2007,23(10):5283-5285
The formation of supramolecular polymeric aggregates with a molecular mass of 100 kDa in a nonaqueous solution from a telechelic dimer of isopropylidene guanosine in the presence of K(+) ions is reported. The possible structure of macromonomers resulting from the development of G4 quartets was deduced from DOSY NMR, circular dichroism spectra, and dynamic light scattering measurements. 相似文献
124.
Balkis Aouadi Flora Vitalis Zsanett Bodor John-Lewis Zinia Zaukuu Istvan Kertesz Zoltan Kovacs 《Molecules (Basel, Switzerland)》2022,27(2)
Coffee is both a vastly consumed beverage and a chemically complex matrix. For a long time, an arduous chemical analysis was necessary to resolve coffee authentication issues. Despite their demonstrated efficacy, such techniques tend to rely on reference methods or resort to elaborate extraction steps. Near infrared spectroscopy (NIRS) and the aquaphotomics approach, on the other hand, reportedly offer a rapid, reliable, and holistic compositional overview of varying analytes but with little focus on low concentration mixtures of Robusta-to-Arabica coffee. Our study aimed for a comparative assessment of ground coffee adulteration using NIRS and liquid coffee adulteration using the aquaphotomics approach. The aim was to demonstrate the potential of monitoring ground and liquid coffee quality as they are commercially the most available coffee forms. Chemometrics spectra analysis proved capable of distinguishing between the studied samples and efficiently estimating the added Robusta concentrations. An accuracy of 100% was obtained for the varietal discrimination of pure Arabica and Robusta, both in ground and liquid form. Robusta-to-Arabica ratio was predicted with R2CV values of 0.99 and 0.9 in ground and liquid form respectively. Aquagrams results accentuated the peculiarities of the two coffee varieties and their respective blends by designating different water conformations depending on the coffee variety and assigning a particular water absorption spectral pattern (WASP) depending on the blending ratio. Marked spectral features attributed to high hydrogen bonded water characterized Arabica-rich coffee, while those with the higher Robusta content showed an abundance of free water structures. Collectively, the obtained results ascertain the adequacy of NIRS and aquaphotomics as promising alternative tools for the authentication of liquid coffee that can correlate the water-related fingerprint to the Robusta-to-Arabica ratio. 相似文献
125.
Franguelli Fernanda Paiva Barta-Holló Berta Petruševski Vladimir M. Sajó Istvan E. Klébert Szilvia Farkas Attila Bódis Eszter Szilágyi Imre Miklós Pawar Rajendra P. Kótai László 《Journal of Thermal Analysis and Calorimetry》2021,145(6):2907-2923
Journal of Thermal Analysis and Calorimetry - Detailed vibrational (IR, Raman, far-IR) and thermal (TGA, TG–MS, DSC) analysis has been performed on... 相似文献
126.
Structural Chemistry - 相似文献
127.
Structural Chemistry - Donald L.D. Caspar (1927–2021) devoted his career to understanding the structure of viruses. He interacted with leading structural scientists of his time and... 相似文献
128.
Istvan Hargittai 《Structural chemistry》2011,22(3):489-496
Alexander G. Ogston (1911–1996) investigated hyaluronic acid and other biopolymers with physico-chemical techniques. He investigated
the behavior of macromolecules in solution in the presence of other macromolecules and described the exclusion effect, known
also as molecular crowding. He determined that the molecular weight and many physico-chemical properties of biopolymers depend
on their origins and the conditions of their preparation. 相似文献
129.
Structural Chemistry - There is hardly a generic connection between the partial atomic charges, a useful concept in chemistry, and the “fractionalization” of the electron accomplished... 相似文献
130.
Squalyl Crown Ether Self‐Assembled Conjugates: An Example of Highly Selective Artificial K+ Channels
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Dr. Zhanhu Sun Dr. Arnaud Gilles Istvan Kocsis Dr. Yves‐Marie Legrand Eddy Petit Dr. Mihail Barboiu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):2158-2164
The natural KcsA K+ channel, one of the best‐characterized biological pore structures, conducts K+ cations at high rates while excluding Na+ cations. The KcsA K+ channel is of primordial inspiration for the design of artificial channels. Important progress in improving conduction activity and K+/Na+ selectivity has been achieved with artificial ion‐channel systems. However, simple artificial systems exhibiting K+/Na+ selectivity and mimicking the biofunctions of the KcsA K+ channel are unknown. Herein, an artificial ion channel formed by H‐bonded stacks of squalyl crown ethers, in which K+ conduction is highly preferred to Na+ conduction, is reported. The K+‐channel behavior is interpreted as arising from discreet stacks of dimers resulting in the formation of oligomeric channels, in which transport of cations occurs through macrocycles mixed with dimeric carriers undergoing dynamic exchange within the bilayer membrane. The present highly K+‐selective macrocyclic channel can be regarded as a biomimetic alternative to the KcsA channel. 相似文献