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121.
122.
Gary Teng Christopher P. Walczak Philip J. Squattrito Dillip K. Mohanty William Scharer Mark R. Giolando Kristin Kirschbaum 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(2):o76-o80
4,6‐Dinitro‐N,N′‐di‐n‐octylbenzene‐1,3‐diamine, C22H38N4O4, (I), 4,6‐dinitro‐N,N′‐di‐n‐undecylbenzene‐1,3‐diamine, C28H50N4O4, (II), and N,N′‐bis(2,4‐dinitrophenyl)octane‐1,8‐diamine, C20H24N6O8, (III), are the first synthetic meta‐dinitroarenes functionalized with long‐chain aliphatic amine groups to be structurally characterized. The intra‐ and intermolecular interactions in these model compounds provide information that can be used to help understand the physical properties of corresponding polymers with similar functionalities. Compounds (I) and (II) possess near‐mirror symmetry, with the octyl and undecyl chains adopting fully extended anti conformations in the same direction with respect to the ring. Compound (III) rests on a center of inversion that occupies the mid‐point of the central C—C bond of the octyl chain. The middle six C atoms of the chain form an anti arrangement, while the remaining two C atoms take hard turns almost perpendicular to the rest of the chain. All three molecules display intramolecular N—H...O hydrogen bonds between the amine and nitro groups, with the same NH group forming a bifurcated intermolecular hydrogen bond to the nitro O atom of an adjacent molecule. In each case, these interactions link the molecules into one‐dimensional molecular chains. In (I) and (II), these chains pack so that the pendant alkyl groups are interleaved parallel to one another, maximizing nonbonded C—H contacts. In (III), the alkyl groups are more isolated within the molecular chains and the primary nonbonded contacts between the chains appear to involve the nitro groups not involved in the hydrogen bonding. 相似文献
123.
Zbigniew Walczak 《Physics letters. A》2010,374(39):3999-4002
We examine the problem of detection of genuine multipartite classical correlations. We first show that genuine multipartite classical correlations cannot be reliably detected by analyzing the multipartite covariances, and then we introduce an information-theoretic approach to the problem of detection of such correlations. 相似文献
124.
Coherent electronic transport through a molecular device is studied using non-equilibrium Green's function (NEGF) formalism.
Such device is made of atomic nanowire which is connected to ferromagnetic electrodes. The molecule itself is described with
the help of Hubbard model (Coulomb interactions are treated by means of the Hartree-Fock approximation), while the coupling
to the electrodes is modeled through the use of a broad-band theory. It was shown that magnetoresistance varies periodically
with increasing length of the atomic wire (in the linear response regime) and oscillates with increasing bias voltage (in
the nonlinear response regime). Since the TMR effect for analyzed structures is predicted to be large (tens of percent), these
junctions seem to be suitable for application as magnetoresistive elements in future electronic circuits. 相似文献
125.
N. Guskos J. Typek M. Wabia V. Likodimos H. Fuks I. Rychlowska-Himmel J. Walczak 《Applied magnetic resonance》1998,14(2-3):397-402
The temperature dependence of the EPR spectrum for the α-phase of iron tungstate has been investigated in the temperature range of 40–260 K. At temperatures betweenT 1 ≈ 250 K andT 2 ≈ 205 K where the antiferromagnetic phase transition occurs, a relatively narrow EPR line arising from the dominant iron(III) species has emerged, gaining intensity with the temperature increase. Its linewidth temperature evolution could be described by Huber equation, with TN = 200 K, which is consistent with the peak seen in magnetic susceptibility measurements, while the correspondingg-factor shifts to higher fields reflecting the build-up of internal field emerging from increasing shortrange order in the spin system. At temperatures lower than T2, a very broad and distorted EPR line with temperature dependentg-factor and linewidth has been observed reflecting the corresponding rise of the magnetic susceptibility below the antiferromagnetic phase transition, presumably arising from magnetic clusters embedded in the antiferromagnetic background. 相似文献
126.
Non-equilibrium Green's functions (NEGF) formalism combined with extended Hückel (EHT) and charging model are used to study
electrical conduction through single-molecule junctions. The analyzed molecular complex is composed of the asymmetric 1,4-Bis((2′-para-mercaptophenyl)-ethinyl)-2-acetyl-amino-5-nitrobenzene molecule symmetrically coupled to two gold electrodes. Owing to this
model, the accurate values of the current flowing through such junctions can be obtained by utilizing basic fundamentals and
coherently deriving model parameters. Furthermore, the influence of the charging effect on the transport characteristics is
emphasized. In particular, charging-induced reduction of conductance gap, charging-induced rectification effect and charging-generated
negative value of the second derivative of the current with respect to voltage are observed and examined for the molecular
complex. 相似文献
127.
128.
Dr. Aleksandr Savateev Dr. Nadezda V. Tarakina Dr. Volker Strauss Dr. Tanveer Hussain Katharina ten Brummelhuis José Manuel Sánchez Vadillo Yevheniia Markushyna Stefano Mazzanti Dr. Alexander P. Tyutyunnik Dr. Ralf Walczak Dr. Martin Oschatz Prof. Dirk M. Guldi Prof. Amir Karton Prof. Markus Antonietti 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(35):15172-15180
129.
Swartz HM Burke G Coey M Demidenko E Dong R Grinberg O Hilton J Iwasaki A Lesniewski P Kmiec M Lo KM Nicolalde RJ Ruuge A Sakata Y Sucheta A Walczak T Williams BB Mitchell C Romanyukha A Schauer DA 《Radiation measurements》2007,42(6-7):1075-1084
As a result of terrorism, accident, or war, populations potentially can be exposed to doses of ionizing radiation that could cause direct clinical effects within days or weeks. There is a critical need to determine the magnitude of the exposure to individuals so that those with significant risk have appropriate procedures initiated immediately, while those without a significant probability of acute effects can be reassured and removed from the need for further consideration in the medical/emergency system. In many of the plausible scenarios there is an urgent need to make the determination very soon after the event and while the subject is still present. In vivo EPR measurements of radiation-induced changes in the enamel of teeth is a method, perhaps the only such method, which can differentiate among doses sufficiently for classifying individuals into categories for treatment with sufficient accuracy to facilitate decisions on medical treatment. In its current state, the in vivo EPR dosimeter can provide estimates of absorbed dose with an error approximately +/- 50 cGy over the range of interest for acute biological effects of radiation, assuming repeated measurements of the tooth in the mouth of the subject. The time required for acquisition, the lower limit, and the precision are expected to improve, with improvements in the resonator and the algorithm for acquiring and calculating the dose. The magnet system that is currently used, while potentially deployable, is somewhat large and heavy, requiring that it be mounted on a small truck or trailer. Several smaller magnets, including an intraoral magnet are under development, which would extend the ease of use of this technique. 相似文献
130.
Walczak M Kozaczek E Szymura-Oleksiak J Pękala E 《Biomedical chromatography : BMC》2011,25(3):381-390
A sensitive and selective liquid chromatographic–electrospray ionization mass spectrometric method for the simultaneous determination of propentofylline and enantiomers of its active metabolite M1 in rat serum, cortex and hippocampus was developed and validated according to GLP procedures. Sample preparations were carried out by liquid–liquid extraction using diethyl ether after the addition of the internal standard (pentoxifylline). The dried residue was reconstituted in mobile phase and injected onto a Chiralpak AD column (10 µm, 250 × 4.6 mm i.d.). The limit of quantification for propentofylline in serum, cortex and hippocampus was set at 0.25 ng/mL and for enantiomers of its metabolite M1 at 1.25 ng/mL. The established LC/ESI‐MS/MS method has been successfully applied to an initial pharmacokinetic study of propentofylline and also to assessment of distribution of parent drug and enantiomers of its pharmacologically active metabolite M1 to cortex and hippocampus after intravenous administration of propentofylline to rats at a dose of 5 mg/kg. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献