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131.
Bazzicalupi C Bencini A Ciattini S Denat F Désogère P Goze C Matera I Valtancoli B 《Dalton transactions (Cambridge, England : 2003)》2010,39(48):11643-11653
The basicity properties of the two cryptands L1 and L2, featuring, respectively, a dibenzofuran or a diphenyl ether moiety bridging the 1,7 positions of a 1,4,7,10-tetraazacyclododecane macrocycle (cyclen) have been studied by means of potentiometric, UV-vis and fluorescence emission measurements. Both ligands show a high basicity in the first protonation step, the first basicity constant of L1 being too high to be measured in aqueous solution. The crystal structure of {[HL1]L1}(+) shows that the NH(2)(+) group is involved in an intramolecular hydrogen bonding network, which justifies the observed high basicity in solution. (1)H, (13)C NMR, UV-vis and fluorescence emission measurements show that, among first row divalent metal cations, both L1 and L2 selectively bind in acetonitrile Cu(II) and Zn(II), which are encapsulated within the ligand cavities. Zn(II) coordination is accompanied by a remarkable increase of the fluorescence emission of the ligands, pointing out that the molecular architecture displayed by L1 and L2 can be used to develop new OFF/ON chemosensors for this metal cation. 相似文献
132.
Interaction between GUVs and catanionic nanocontainers: new insight into spontaneous membrane fusion
Mauroy C Castagnos P Blache MC Teissié J Rico-Lattes I Rols MP Blanzat M 《Chemical communications (Cambridge, England)》2012,48(53):6648-6650
Spontaneous receptor-free membrane fusion with pure lipid systems, used as a cell membrane model, is demonstrated with easy-to-handle lactose-derived catanionic vesicles. This fusion, mediated and controlled by phospholipids, emphasizes the great value of these nanovesicles for enhanced direct cytosolic drug delivery without the shortcomings linked with endocytic pathways. 相似文献
133.
134.
Thompson M Ellison SL Owen L Mathieson K Powell J Key P Wood R Damant AP 《Journal of AOAC International》2006,89(1):232-239
The study considers data from 2 UK-based proficiency schemes and includes data from a total of 29 rounds and 43 test materials over a period of 3 years. The results from the 2 schemes are similar and reinforce each other. The amplification process used in quantitative polymerase chain reaction determinations predicts a mixture of normal, binomial, and lognormal distributions dominated by the latter 2. As predicted, the study results consistently follow a positively skewed distribution. Log-transformation prior to calculating z-scores is effective in establishing near-symmetric distributions that are sufficiently close to normal to justify interpretation on the basis of the normal distribution. 相似文献
135.
A. Gilbert Cook Christine A. Schering Pauline A. Campbell Samantha S. Hayes 《Tetrahedron letters》2005,46(33):5451-5454
Heat pyrolysis of the oxazines formed from 2-piperidineethanol produced 2,3-dehydropiperidine enamines. The same results were observed when these oxazines were irradiated with microwaves. Various 2-substituted perhydrooxazines were synthesized by allowing 2-piperidineethanol or 2-piperidinemethanol to react with aldehydes or ketones. 相似文献
136.
Pauline Coolen-Schrijner Erik A. van Doorn 《Methodology and Computing in Applied Probability》2006,8(4):449-465
This paper is concerned with the circumstances under which a discrete-time absorbing Markov chain has a quasi-stationary distribution.
We showed in a previous paper that a pure birth-death process with an absorbing bottom state has a quasi-stationary distribution—actually
an infinite family of quasi-stationary distributions— if and only if absorption is certain and the chain is geometrically
transient. If we widen the setting by allowing absorption in one step (killing) from any state, the two conditions are still necessary, but no longer sufficient. We show that the birth–death-type of behaviour
prevails as long as the number of states in which killing can occur is finite. But if there are infinitely many such states,
and if the chain is geometrically transient and absorption certain, then there may be 0, 1, or infinitely many quasi-stationary
distributions. Examples of each type of behaviour are presented. We also survey and supplement the theory of quasi-stationary
distributions for discrete-time Markov chains in general.
相似文献
137.
138.
Xavier Bantreil Nasreddine Kanfar Nicolas GehinEthan Golliard Pauline OhlmannJean Martinez Frédéric Lamaty 《Tetrahedron》2014
A convenient and user-friendly method to yield benzamides from primary and secondary amines and various benzylic alcohols in the presence of a cheap iron salt (FeCl2·4H2O) and tert-butylhydroperoxide (70% in water) as a stoichiometric oxidant is described. Control experiments indicated that this reaction might involve radical species. This method proved to be general, generating a family of 30 benzamides and was applied to the preparative synthesis of anti-anxiety drug moclobemide. 相似文献
139.
Lianghu Gu Dr. Gopinadhanpillai Gopakumar Dr. Pauline Gualco Prof. Walter Thiel Dr. Manuel Alcarazo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8575-8578
We report the synthesis of [H2B(pz)2PR]+, [H2C(pz)2PR]+2, [HB(pz)3P]+2, and [HC(pz)3P]+3 (H2B(pz)2=bis(pyrazolyl)borate; H2C(pz)2=bis(pyrazolyl)methane; HB(pz)3=tris(pyrazolyl)borate; HC(pz)3=tris(pyrazolyl) methane; R=Ph, Cy or Et2N) by reaction of the corresponding neutral or anionic ligands with chlorophosphines in the presence of TMSOTf. The structures of these compounds were determined by X‐ray crystallographic analysis and the nature of their bonding was examined using density functional theory. 相似文献
140.
Energy spectra considerations for synchrotron radiotherapy trials on the ID17 bio‐medical beamline at the European Synchrotron Radiation Facility
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Jeffrey C. Crosbie Pauline Fournier Stefan Bartzsch Mattia Donzelli Iwan Cornelius Andrew W. Stevenson Herwig Requardt Elke Bräuer‐Krisch 《Journal of synchrotron radiation》2015,22(4):1035-1041
The aim of this study was to validate the kilovoltage X‐ray energy spectrum on the ID17 beamline at the European Synchrotron Radiation Facility (ESRF). The purpose of such validation was to provide an accurate energy spectrum as the input to a computerized treatment planning system, which will be used in synchrotron microbeam radiotherapy trials at the ESRF. Calculated and measured energy spectra on ID17 have been reported previously but recent additions and safety modifications to the beamline for veterinary trials warranted a fresh investigation. The authors used an established methodology to compare X‐ray attenuation measurements in copper sheets (referred to as half value layer measurements in the radiotherapy field) with the predictions of a theoretical model. A cylindrical ionization chamber in air was used to record the relative attenuation of the X‐ray beam intensity by increasing thicknesses of high‐purity copper sheets. The authors measured the half value layers in copper for two beamline configurations, which corresponded to differing spectral conditions. The authors obtained good agreement between the measured and predicted half value layers for the two beamline configurations. The measured first half value layer was 1.754 ± 0.035 mm Cu and 1.962 ± 0.039 mm Cu for the two spectral conditions, compared with theoretical predictions of 1.763 ± 0.039 mm Cu and 1.984 ± 0.044 mm Cu, respectively. The calculated mean energies for the two conditions were 105 keV and 110 keV and there was not a substantial difference in the calculated percentage depth dose curves in water between the different spectral conditions. The authors observed a difference between their calculated energy spectra and the spectra previously reported by other authors, particularly at energies greater than 100 keV. The validation of the beam spectrum by the copper half value layer measurements means the authors can provide an accurate spectrum as an input to a treatment planning system for the forthcoming veterinary trials of microbeam radiotherapy to spontaneous tumours in cats and dogs. 相似文献