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71.
72.
Several multi-criteria-decision-making methodologies assume the existence of weights associated with the different criteria, reflecting their relative importance.One of the most popular ways to infer such weights is the analytic hierarchy process, which constructs first a matrix of pairwise comparisons, from which weights are derived following one out of many existing procedures, such as the eigenvector method or the least (logarithmic) squares. Since different procedures yield different results (weights) we pose the problem of describing the set of weights obtained by “sensible” methods: those which are efficient for the (vector-) optimization problem of simultaneous minimization of discrepancies. A characterization of the set of efficient solutions is given, which enables us to assert that the least-logarithmic-squares solution is always efficient, whereas the (widely used) eigenvector solution is not, in some cases, efficient, thus its use in practice may be questionable.This research has been supported by the Spanish Science and Technology Ministry and FEDER Grants No. BFM2002-04525-C02-02 and BFM2002-11282-E. 相似文献
73.
Eduardo Conde 《Operations Research Letters》2005,33(5):481-485
In this paper, a linear-time algorithm is developed for the minmax-regret version of the continuous unbounded knapsack problem with n items and uncertain objective function coefficients, where the interval estimates for these coefficients are known. This improves the previously known bound of time for this optimization problem. 相似文献
74.
van Eis MJ van Der Linde BS de Kanter FJ de Wolf WH Bickelhaupt F 《The Journal of organic chemistry》2000,65(14):4348-4354
In contrast to the terminal phosphinidene complex PhPW(CO)(5) (2), which adds to [5]metacyclophane (1) in a 1,4-fashion, dichlorocarbene preferentially adds in a 1,2-fashion to the formal "anti-Bredt" type double bond of the aromatic ring of 1 to afford the norcaradiene 11b, which immediately rearranges to the bridged cycloheptatriene 12b and further by a [1,5] sigmatropic chlorine migration to the isomeric 13b as the first observable product. More slowly, the latter isomerizes via a dissociative mechanism to give 15b. A computational study supports the notion that the [1,5] chlorine migration in the rearrangement 12b --> 13b, for which an activation barrier of 70.2 kJ mol(-)(1) was calculated, is essentially concerted with minor charge separation. In contrast, the analogous [1,5] chlorine migration in the flat model compound 7,7-dichlorocycloheptatriene (12a) displays features of a dissociative pathway. 相似文献
75.
76.
77.
F. Kottmann W. Amir F. Biraben C. A. N. Conde S. Dhawan T. W. Hänsch F. J. Hartmann V. W. Hughes O. Huot P. Indelicato L. Julien P. Knowles S. Kazamias Y.-W. Liu F. Mulhauser F. Nez R. Pohl P. Rabinowitz J. M. F. dos Santos L. A. Schaller H. Schneuwly W. Schott D. Taqqu J. F. C. A. Veloso 《Hyperfine Interactions》2001,138(1-4):55-60
A measurement of the 2S Lamb shift in muonic hydrogen (μ−p) is being prepared at the Paul Scherrer Institute (PSI). The goal of the experiment is to measure the energy difference
ΔE(25
P
3/2−23
S
1/2) by laser spectroscopy (λ≈6μm) to a precision of 30 ppm and to deduce the root mean square (rms) proton charge radius with
10−3 relative accuracy, 20 times more precise than presently known.
An important prerequisite to this experiment is the availability of long-lived μp2S
-atoms. A 2S-lifetime of ∼1 μs – sufficiently long to perform the laser experiment – at H2 gas pressures of 1–2 hPa was deduced from recent measurements of the collisional 2S-quenching rate. A new low-energy negative muon beam yields an order of magnitude more muon stops in a small low-density gas
volume than a conventional cloud muon beam. A stack of ultra-thin carbon foils is the key element of a fast detector for keV-muons.
The development of a 2 keV X-ray detector and a 3-stage laser system providing 0.5 mJ laser pulses at 6 μm is on the way.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
78.
Laser Ablation Synthesis of Gold Selenides by using a Mass Spectrometer as a Synthesizer: Laser Desorption Ionization Time‐of‐Flight Mass Spectrometry
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Dr. Lubomír Prokeš Prof. Pavel Kubáček Prof. Eladia Maria Peña‐Méndez Dr. Filippo Amato Prof. José Elias Conde Dr. Milan Alberti Prof. Josef Havel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(32):11261-11268
Methods for the rapid construction of new chemical motifs have the potential to accelerate the development of nanoscience. The synthesis of new chemical entities by laser ablation has been systematically demonstrated by using mixtures of gold and selenium. The compounds generated are detected by time‐of‐flight mass spectrometry and, for selected compounds, the structure is investigated by using density functional theory optimization. In total, 67 new gold selenide clusters have been synthesized, demonstrating an unsuspected richness in gold chemistry. Chemical species generated in the gas phase might inspire new routes for the synthesis of novel compounds in the solid state. 相似文献
79.
Sebastian Sewerin Marco Taubert Henning Vollmann Virginia Conde Arno Villringer Patrick Ragert 《BMC neuroscience》2011,12(1):1-5
Background
The aberrant pyramidal tract (APT) refers to the collateral pathway of the pyramidal tract (PT) through the medial lemniscus in the midbrain and pons. Using diffusion tensor tractography (DTT), we investigated the characteristics of the APT in comparison with the PT in the normal human brain.Results
In thirty-four (18.3%, right hemisphere: 20, left hemisphere: 14) of the 186 hemispheres, the APTs separated from the PT at the upper midbrain level, descended through the medial lemniscus from the midbrain to the pons, and then rejoined with the PT at the upper medulla. Nine (26.5%) of the 34 APTs were found to originate from the primary somatosensory cortex without a primary motor cortex origin. Values of fractional anisotropy (FA) and tract volume of the APT were lower than those of the PT (P < 0.05); however, no difference in mean diffusivity (MD) value was observed (P > 0.05).Conclusion
We found that the APT has different characteristics, including less directionality, fewer neural fibers, and less origin from the primary motor cortex than the PT. 相似文献80.
He Li Joo Conde Ana Guerreiro Gonalo J. L. Bernardes 《Angewandte Chemie (International ed. in English)》2020,59(37):16023-16032
The bioorthogonal inverse‐electron‐demand Diels–Alder (IEDDA) cleavage reaction between tetrazine and trans‐cyclooctene (TCO) is a powerful way to control the release of bioactive agents and imaging probes. In this study, a pretargeted activation strategy using single‐walled carbon nanotubes (SWCNTs) that bear tetrazines (TZ@SWCNTs) and a TCO‐caged molecule was used to deliver active effector molecules. To optimize a turn‐on signal by using in vivo fluorescence imaging, we developed a new fluorogenic near‐infrared probe that can be activated by bioorthogonal chemistry and image tumours in mice by caging hemicyanine with TCO (tHCA). With our pretargeting strategy, we have shown selective doxorubicin prodrug activation and instantaneous fluorescence imaging in living cells. By combining a tHCA probe and a pretargeted bioorthogonal approach, real‐time, non‐invasive tumour visualization with a high target‐to‐background ratio was achieved in a xenograft mice tumour model. The combined advantages of enhanced stability, kinetics and biocompatibility, and the superior pharmacokinetics of tetrazine‐functionalised SWCNTs could allow application of targeted bioorthogonal decaging approaches with minimal off‐site activation of fluorophore/drug. 相似文献