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961.
962.
Guido Haak 《Proceedings of the American Mathematical Society》1998,126(5):1547-1548
We give a new proof of a theorem by M.P. do Carmo and M. Dajczer on helicoidal surfaces of constant mean curvature.
963.
964.
A new model is presented for the discharge mechanism of MNOS memory devices. For moderate and large charge contents the discharging effect can actually be ascribed to the compensation of the stored charge by the injection from the silicon into the nitride of carriers of the opposite type. 相似文献
965.
Konrad Fischer Dewey Frank Bazarre Guido Bell Berthold Kegel und Gerhard Liebel 《Fresenius' Journal of Analytical Chemistry》1983,314(3):289-292
Zusammenfassung Die Herstellung feinstrukturierter Schaltungen in der Elektronik hat zu neuen Strukturierungsverfahren geführt, die heute im Produktionsmaßstab eingesetzt werden. Im folgenden Beitrag wird die Ionenstrahl- und Plasmaätztechnik in ihren Prinzipien und ihrer praktischen Anwendung dargelegt.
Für anregende und hilfreiche Beiträge in einer Reihe von Erörterungen danken die Autoren Herrn Gerhard Lässing und Herrn Dr. Frank Stephany von der Firma AEG-Telefunken, Heilbronn. 相似文献
Application and analytical problems of ion beam etching and plasma etching in structuring of electronic devices
Summary The manufacturing of fine line geometries in electronic circuits requires new technologies. This paper describes principles and practical applications of ion milling and plasma etching.
Für anregende und hilfreiche Beiträge in einer Reihe von Erörterungen danken die Autoren Herrn Gerhard Lässing und Herrn Dr. Frank Stephany von der Firma AEG-Telefunken, Heilbronn. 相似文献
966.
Hadjar O Schlathölter T Davila S Catledge SA Kuhn K Kassan S Kibelka G Cameron C Verbeck GF 《Journal of the American Society for Mass Spectrometry》2011,22(10):1872-1884
A recently described ion charge coupled device detector IonCCD (Sinha and Wadsworth, Rev. Sci. Instrum. 76(2), 2005; Hadjar, J. Am. Soc. Mass Spectrom. 22(4), 612–624, 2011) is implemented in a miniature mass spectrometer of sector-field instrument type and Mattauch-Herzog (MH)-geometry (Rev.
Sci. Instrum. 62(11), 2618–2620, 1991; Burgoyne, Hieftje and Hites J. Am. Soc. Mass Spectrom. 8(4), 307–318, 1997; Nishiguchi, Eur. J. Mass Spectrom. 14(1), 7–15, 2008) for simultaneous ion detection. In this article, we present first experimental evidence for the signature of energy loss
the detected ion experiences in the detector material. The two energy loss processes involved at keV ion kinetic energies
are electronic and nuclear stopping. Nuclear stopping is related to surface modification and thus damage of the IonCCD detector
material. By application of the surface characterization techniques atomic force microscopy (AFM) and X-ray photoelectrons
spectroscopy (XPS), we could show that the detector performance remains unaffected by ion impact for the parameter range observed
in this study. Secondary electron emission from the (detector) surface is a feature typically related to electronic stopping.
We show experimentally that the properties of the MH-mass spectrometer used in the experiments, in combination with the IonCCD,
are ideally suited for observation of these stopping related secondary electrons, which manifest in reproducible artifacts
in the mass spectra. The magnitude of the artifacts is found to increase linearly as a function of detected ion velocity.
The experimental findings are in agreement with detailed modeling of the ion trajectories in the mass spectrometer. By comparison
of experiment and simulation, we show that a detector bias retarding the ions or an increase of the B-field of the IonCCD
can efficiently suppress the artifact, which is necessary for quantitative mass spectrometry. 相似文献
967.
Francesca Caterina Izzo Elisabetta Zendri Guido Biscontin Eleonora Balliana 《Journal of Thermal Analysis and Calorimetry》2011,104(2):541-546
Thermogravimetry coupled with differential scanning calorimetry (TG–DSC) has been commonly used in the field of conservation
of Cultural Heritage for the study of art objects, especially for the characterisation of inorganic matrixes. In recent years,
thermal analyses have been applied to the study of organic painting materials. The advantages of performing TG–DSC are linked
to the fact that it is micro-destructive technique which does not require any treatment prior the analysis and provide useful
information in relatively short time. The aim of this study is to describe the application of TG–DSC on the study of oil binders
used in contemporary paints. Even if synthetic binders have become increasingly popular in the 20th century, many contemporary
artists still prefer the more traditional media: drying oils. Although the wish of recalling traditional methods, much practical
knowledge in paint preparation by mixing drying oil and pigments and in the behaviour of the mixture has been lost. This is
mainly due to the different composition of contemporary materials in comparison with the traditional ones and may sometimes
lead to different drying properties of the oil paint formulations and consequent problems in the art creation and conservation.
For answer to this artistic need and in particular to the difficulties outlined by artists themselves in producing and employing
oil paints, unpigmented and pigmented oil films were studied after a week, 1 and 2 years of natural drying under laboratory
conditions. Thermal analyses were performed in air flow: the focus of this research was, in fact, to study the thermal and
oxidative behaviours of young films for better understanding the very first processes leading to the formation of the film. 相似文献
968.
Moalin M Strijdonck GP Beckers M Hagemen G Borm P Bast A Haenen GR 《Molecules (Basel, Switzerland)》2011,16(11):9636-9650
The polyphenol quercetin (Q) that has a high antioxidant capacity is a lead compound in the design of antioxidants. We investigated the possibility of modifying quercetin while retaining its antioxidant capacity as much as possible. To this end, the antioxidant capacities of Q, rutin, monohydroxyethyl rutinoside (monoHER) and a series of synthesized methylated Q derivatives were determined. The results confirm that the electron donating effect of the hydroxyl groups is essential. It was also found that the relatively planar structure of Q needs to be conserved. This planar conformation enables the distribution of the electron donating effect through the large conjugated π-system over the entire molecule. This is essential for the cooperation between the electron donating groups. Based on the activity of the compounds tested, it was concluded that structural modification at the 5 or 7 position is the most optimal to retain most of the antioxidant capacity of Q. This was confirmed by synthesizing and testing Q5OMe (Q6) and Q7OMe (Q7) that indeed displayed antioxidant capacities closest to Q. 相似文献
969.
970.