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121.
D. Habs O. Kester T. Sieber H. Bongers S. Emhofer P. Reiter P.G. Thirolf G. Bollen J. Aystö O. Forstner H. Ravn T. Nilsson M. Oinonen H. Simon J. Cederkall F. Ames P. Schmidt G. Huber L. Liljeby O. Skeppstedt K.G. Rensfelt F. Wenander B. Jonson G. Nyman R. von Hahn H. Podlech R. Repnow C. Gund D. Schwalm A. Schempp K.-U. Kühnel C. Welsch U. Ratzinger G. Walter A. Huck K. Kruglov M. Huyse P. Van den Bergh P. Van Duppen L. Weissman A.C. Shotter A.N. Ostrowski T. Davinson P.J. Woods J. Cub A. Richter G. Schrieder 《Hyperfine Interactions》2000,129(1-4):43-66
The Radioactive Beam Experiment REX-ISOLDE [1–3] is a pilot experiment at ISOLDE (CERN) testing the new concept of post acceleration
of radioactive ion beams by using charge breeding of the ions in a high charge state ion source and the efficient acceleration
of the highly charged ions in a short LINAC using modern ion accelerator structures. In order to prepare the ions for the
experiments singly charged radioactive ions from the on-line mass separator ISOLDE will be cooled and bunched in a Penning
trap, charge bred in an electron beam ion source (EBIS) and finally accelerated in the LINAC. The LINAC consists of a radiofrequency
quadrupole (RFQ) accelerator, which accelerates the ions up to 0.3 MeV/u, an interdigital H-type (IH) structure with a final
energy between 1.1 and 1.2 MeV/u and three seven gap resonators, which allow the variation of the final energy. With an energy
of the radioactive beams between 0.8 MeV/u and 2.2 MeV/u a wide range of experiments in the field of nuclear spectroscopy,
astrophysics and solid state physics will be addressed by REX-ISOLDE.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
122.
Beckmann U Dietrich W Radeglia R 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1999,137(1):132-137
Up to now, three subspectra are usually needed for the complete assignment of all signals in 13C spectrum: two DEPT spectra (phi = 90 degrees and phi = 135 degrees) and a proton decoupled spectrum. In this paper, we present a method in which a complete assignment becomes possible with merely two spectra. For this purpose, a new pulse sequence (ORSAT) has been elaborated by using off-resonance irradiation. The method described here is a further development of SEFT and APT. The second required spectrum is a DEPT (phi = 135 degrees). Signal assignment of cholesteryl acetate is demonstrated as an example. 13C routine spectroscopy can be significantly accelerated by applying this method. 相似文献
123.
J.S. Becker R.C. Dietrich A. Matusch D. Pozebon V.L. Dressler 《Spectrochimica Acta Part B: Atomic Spectroscopy》2008
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for quantitative imaging of toxic and essential elements in thin sections (thickness of 30 or 40 μm) of tobacco plant tissues. Two-dimensional images of Mg, Fe, Mn, Zn, Cu, Cd, Rh, Pt and Pb in leaves, shoots and roots of tobacco were produced. Sections of the plant tissues (fixed onto glass slides) were scanned by a focused beam of a Nd:YAG laser in a laser ablation chamber. The ablated material was transported with argon as carrier gas to the ICP ion source at a quadrupole ICP-MS instrument. Ion intensities of the investigated elements were measured together with 13C+, 33S+ and 34S+ within the entire plant tissue section. Matrix matching standards (prepared using powder of dried tobacco leaves) were used to constitute calibration curves, whereas the regression coefficient of the attained calibration curves was typically 0.99. The variability of LA-ICP-MS process, sample heterogeneity and water content in the sample were corrected by using 13C+ as internal standard. Quantitative imaging of the selected elements revealed their inhomogeneous distribution in leaves, shoots and roots. 相似文献
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Three carrageenans derived from red algae and three partially modified carrageenans were tested for their ability to inhibit the formation of new blood capillaries on the chorionallantois membrane of the hen egg. It could be clearly demonstrated that they were better angiogenesis inhibitors than the standard compound suramin. 相似文献
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127.
Ruochun Zhang Yulin Qi Chao Ma Jinfeng Ge Qiaozhuan Hu Fu-Jun Yue Si-Liang Li Dietrich A. Volmer 《Molecules (Basel, Switzerland)》2021,26(1)
Lignin is the second most abundant natural biopolymer, which is a potential alternative to conventional fossil fuels. It is also a promising material for the recovery of valuable chemicals such as aromatic compounds as well as an important biomarker for terrestrial organic matter. Lignin is currently produced in large quantities as a by-product of chemical pulping and cellulosic ethanol processes. Consequently, analytical methods are required to assess the content of valuable chemicals contained in these complex lignin wastes. This review is devoted to the application of mass spectrometry, including data analysis strategies, for the elemental and structural elucidation of lignin products. We describe and critically evaluate how these methods have contributed to progress and trends in the utilization of lignin in chemical synthesis, materials, energy, and geochemistry. 相似文献
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130.
Hamid R. Memarian Mohammad Bagheri Dietrich D?pp 《Monatshefte für Chemie / Chemical Monthly》2004,42(3):833-838
In continuation of previous work some novel 3,5-diacetyl-1,4-dihydropyridine derivatives were synthesized and their photochemical behavior was studied under oxygen and argon atmosphere. Oxidation of the dihydropyridine ring and formation of pyridine derivatives was the result of the reaction. The presence of oxygen affects not only on the rate of oxidation, but also the formation of some unidentified by-products was observed on irradiation under this atmosphere. 相似文献