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181.
A novel procedure is proposed for 3D-QSAR analysis. The composition of 16 published QSAR datasets has been examined using Quantitative Series Enrichment Analysis (QSEA). The procedure is based on topomer technologies. A heatmap display in combination with topomer CoMFA and a novel series trajectory analysis revealed critical information for the assembly of structures into meaningful series. Global and local centroid structures can be determined from a similarity distance matrix and build the origins for stepwise model building by increasing the similarity radius around the centroid nucleus. The results indicate that the new procedure allows determination of whether compounds belong to an emerging structure-activity relationship and which compounds can be predicted within reliable limits. 相似文献
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D. Wöhrle A. Wendt A. Weitemeyer J. Stark W. Spiller G. Schneider S. Müller U. Michelsen H. Kliesch A. Heuermann A. Ardeschirpur 《Russian Chemical Bulletin》1994,43(12):1953-1964
A number of porphyrin derivatives based on hematoporphyrin, 5,10,15,20-tetrasubstituted porphyrins, phthalocyanines, and naphthalocyanines were prepared either as low-molecular compounds or bonded with methoxypoly(ethylene glycol) or attached to silica of low surface area. The low-molecular weight and the polymer-bonded porphyrins exhibit comparable triplet lifetimes and activities in the photosensitized formation of singlet oxygen. For photoninduced processes, the monomeric state of sensitizers is fundamentally important. The porphyrins have been investigated as sensitizers for photooxidation of thiolates and sulfides, which occursvia singlet oxygen, and, therefore, is much more efficient than the corresponding catalytic dark oxidation. Polymer-bonded porphyrins and long-wavelength absorbing naphthalocyanines incorporated in liposomes exhibitin vivo high accumulation in tumor tissues. Under irradiation, singlet oxygen is produced, and efficient phototherapeutic effects are observed, which may be used for photodynamic cancer therapy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2071–2082, December, 1994.D. Wöhrle is very thankful to G. Schulz-Ekloff (Bremen), M. Shopova (Sofia), I. Okura (Tokyo), B. Roeder (Berlin), G. Graschew (Heidelberg), and their coworkers for fruitful cooperation. The research was supported by the German Research Society (Deutsche Forschungsgemeinschaft, 436 BUL 113/51/0, Wo 237/ 12-1), the German Cancer Service (Deutsche Krebshilfe, W 15/89/Sch12), Bremen University (FSP 2/90), and the Federal Department of Scientific Research and Tech nology (Bundesministerium far Forschung und Technotogie, Bonn, 13N6290). 相似文献
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High Nuclearity Antimonato‐Polyoxovanadate Cluster {V15Sb6O42} as a Synthon for the Solvothermal in situ Generation of α‐ and β‐{V14Sb8O42} Isomers
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Michael Wendt Prof. Dr. Christian Näther Prof. Dr. Wolfgang Bensch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(23):7747-7751
New heteroatom polyoxovanadates (POVs) were synthesized by applying a water‐soluble high‐nuclearity cluster as new synthon. The [V15Sb6O42]6? cluster shell exhibiting D3 symmetry was in situ transformed into completely different cluster shells, namely, the α‐[V14Sb8O42]4? isomer with D2d and the β‐[V14Sb8O42]4? isomer with D2h symmetry. The solvothermal reaction of {Ni(en)3}3[V15Sb6O42(H2O)x] ? 15 H2O (x=0 or 1; en=ethylenediamine) in water led to the crystallization of [{Ni(en)2}2V14Sb8O42] ? 5.5 H2O containing the β‐isomer. The addition of [Ni(phen)3](ClO4)2 ? 0.5 H2O (phen=1,10‐phenanthroline) to the reaction slurry gave the new compound {Ni(phen)3}2[V14Sb8O42] ? phen ? 12 H2O with the α‐isomer. Both transformation reactions are complex due the change of symmetry, the chemical composition, and rearrangement of the VO5 square pyramids and Sb2O5 handle‐like moieties. 相似文献
187.
H. Wendt 《Mathematische Zeitschrift》1937,42(1):680-696
Ohne ZusammenfassungDiese Arbeit wurde von der Naturwissenschaftlichen Fakultät der Universität Halle als Dissertation angenommen. Sie entstand im Gedankenaustausch mit Herrn W. Hantzsche in Dresden. Die Problemstellung verdanke ich den Herren W. Threlfall und H. Seifert in Dresden, die mich auch bei der Abfassung der Arbeit unterstützten. 相似文献
188.
P. Müller B. A. Bushaw K. Blaum S. Diel Ch. Geppert A. Nähler N. Trautmann W. Nörtershäuser K. Wendt 《Analytical and bioanalytical chemistry》2001,370(5):508-512
41Ca ultratrace determination by diode-laser-based resonance ionization mass spectrometry with extremely high isotopic selectivity
is presented. Application to environmental dosimetry of nuclear reactor components, to cosmochemical investigations of production
cross sections, and biomedical isotope-tracer studies of human calcium kinetics are discussed. Future investigations are possible
use in 41Ca-radiodating. Depending on the application, 41Ca isotopic abundances in the range of 10–9 to 10–15 relative to the dominant stable isotope 40Ca must be determined. Either double- or triple-resonance optical excitation with narrow-band extended cavity diode lasers
and subsequent non-resonant photoionization of calcium in a collimated atomic beam were used. The resulting photoions are
detected with a quadrupole mass spectrometer optimized for background reduction and neighboring mass suppression. Applying
the full triple-resonance scheme provides a selectivity of ∼ 5 × 1012 in the suppression of neighboring isotopes and > 108 for isobars, together with an overall detection efficiency of ∼ 5 × 10–5. Measurements on a variety of sample types are discussed; the accuracy and reproducibility of the resulting 41Ca/40Ca isotope ratios was better than 5%.
Received: 4 January 2001 / Revised: 19 February 2001 / Accepted: 27 February 2001 相似文献
189.
Different approaches of equilibrium structure determinations by the gas-phase electron diffraction (ED) method or by its combination with other relevant techniques have been reviewed. Some problems and limitations of these approaches are discussed. Special attention is paid to various potential energy function models. Different types of equilibrium bond lengths obtained by the optimization of ED data or their combination with experimental and computational spectroscopic data are compared in tables. Relations between different types of vibrational corrections are discussed. Structure data determined by other methods or approaches are given for comparison. 相似文献
190.