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31.
Angelika Jungmann R. Claessen R. Zimmermann Ge Meng P. Steiner S. Hüfner S. Tratzky K. Stöwe H. P. Beck 《Zeitschrift für Physik B Condensed Matter》1995,97(1):25-34
The electronic structure of the layered compounds LaI2 and CeI2 was investigated by photoemission and electron energy loss spectroscopy. From the experimental results we are able to confirm the metallic nature of these compounds, and by using photon energy dependent measurements of the valence band we can identify the orbital character of the conduction band as essentially 5d1-like. A detailed analysis of the Ce 3d and 4f spectra yields a remarkably small 4f-5d hybridization strength, almost completely decoupling the f-electron from the conduction band, which makes CeI2 a somewhat unusual system compared to other metallic Ce compounds. Band structure calculations by Jepsen and Andersen [1] confirm these experimental results. 相似文献
32.
Angelika Betten 《Archiv der Mathematik》1969,20(5):471-480
Ohne Zusammenfassung 相似文献
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Jens Christoffers Thomas Werner Angelika Baro Peter Fischer 《Journal of organometallic chemistry》2004,689(22):3550-3555
A 3-tert-butyl-1-(stannylpropyl)-functionalized cyclopentadienyl ligand precursor 6 is readily available in 64% overall yield from allylic alcohol 1 by a three-step reaction sequence including Pd-catalyzed hydrostannylation with Ph3SnH. Treatment with FeCl2 and ZrCl4 · 2THF afforded corresponding ferrocene and zirconocene derivatives. Transmetallation of Sn-Ph with Li-Bu was observed under these reaction conditions by using BuLi as a base. 相似文献
35.
The Kováts retention indices of all 93 acyclic octenes on polydimethylsiloxane and squalane as stationary phases as well as their mass spectra were measured. The means of gas chromatography-mass spectrometry (GC-MS) were used for confirmation of GC identification as well as for mass spectrometric deconvolution of the majority of gas chromatographic unseparated isomeric octene peaks. The distinction between corresponding E and Z acyclic octenes, that is either difficult or even impossible by means of GC-MS, was obtained on the basis of larger temperature coefficients of retention indices for Z isomeric octenes than for corresponding E isomers. The retention data expressed as homomorphy factors were correlated with the degree of branching, position of double bond, and position of alkyl group with respect to the double bond of acyclic octenes, and the structure-retention relationships were formulated. The 81 acyclic octenes were identified in FCC gasoline. 相似文献
36.
Angelika Bikner-Ahsbahs 《ZDM》2003,35(5):208-223
How does the development of ideal types contribute to an empirically based construction of theories in the interpretative research of mathematics education? Before answering this question I clarify what is meant by the termstheory andideal type. Personal ideal types, ideal types of actions andsituational ideal types are going to be distinguished. Representing research examples. I show that forming ideal types can be considered as a methodical principle for empirically grounded theory construction with common features and different heuristics. 相似文献
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Bernhard Traulich†Eilo Hildebrand‡Angelika Schimz‡Gottfried WagnerJanos K. Lanyi§ 《Photochemistry and photobiology》1983,37(5):577-579
Halobacterium halobium , strain L-33, which is deficient in bacteriorhodopsin (BR) but synthesizes increased amounts of halorhodopsin (HR), shows behavioral responses upon changes in fluence rate with visible light or with UV light. The observations support the earlier report (Schimz et al. , 1982). that BR is not essential for photosensing in H. halobium. In the UV-range, changes in light intensity elicit the maximal response at λ= 370 nm. In the visible range, changes in light intensity show the maximal response at Δ= 565 nm and a secondary peak at Δ= 590 nm. The latter corresponds to the absorption maximum of HR (Δmax = 588 nm). This light-energy converting retinal pigment of H. halobium thus appears to contribute to photosensory behavior. 相似文献
40.
The automation of all aspects of manual solution-phase synthesis into one integrated, efficient, and reliable system could be regarded as something of an unmet challenge in organic chemistry. The requirements for modern solution-phase libraries in mainstream drug discovery is typically 50-250 high-purity compounds on a 10-100-mg scale, whether for target class libraries or lead optimization, and short cycle time in combination with high capacity is critical. To achieve these goals, in a codevelopment between Aventis and Accelab GmbH, Kusterdingen, Germany, we designed a completely novel system of independent workstations connected by a shuttle transfer system produced by Montech, Derendingen, Switzerland. Seven modular workstations process four reactions on each shuttle in parallel, with the ability to perform synthesis (temperature control and liquid reagent handling), filtration, liquid-liquid extraction, evaporation, weighing, solid-phase extraction, and HPLC/MS analysis. The modular design enables the continuous loading of shuttles at any time, and each shuttle can have its own workflow. The design also allows easy expansion for future needs. The result is a combination of high flexibility and high throughput. 相似文献