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21.
J.A. Pinston W. Mampe R. Roussille K. Schreckenbach D. Heck H.G. Börner H.R. Koch S. Andre D. Barneoud 《Nuclear Physics A》1979,321(1):25-44
Gamma and electron spectra following thermal neutron capture on 99Tc have been studied with a bent-crystal spectrometer, Ge(Li) and Si(Li) detectors and a magnetic spectrometer. Prompt and delayed γ-γ coincidences with Ge(Li) detectors have been performed. A level scheme is proposed for 100Tc comprising 21 excited states up to 640 keV. The binding energy of the last neutron in 100Tc was deduced. For most levels, spin and parity values were assigned. Two isometric transitions of respective half-lives 10.2 and 4.6 μs have been identified using the 100Mo(d, 2n)100Tc reaction with a pulsed beam of deuterons. From the comparison of the present (n, γ) study and the collaborative study of the 99Tc(d, p) reaction, several members of the multiplets , , and have been identified. 相似文献
22.
Lipton AS Heck RW Sears JA Ellis PD 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2004,168(1):66-74
Solid-state NMR spectroscopy of half-integer quadrupolar nuclides has received a lot of interest recently with the advent of new methodologies and higher magnetic fields. We present here the extension of our previous low temperature method to an 18.8T system. This new probe entailed a total redesign including a cross coil and variable capacitors that are operational at cryogenic temperatures. The limitations to sensitivity are also discussed; including a new diode network, the utilization of a cryogenic band pass filter, and the consequences of the RF profiles of the coil. Further, details of the spectroscopy of quadrupolar nuclei in a protein are discussed, such as the observation of the outer transitions and how to distinguish them from the desired +/-1/2 transition. 相似文献
23.
Melting points in mixtures of a crystallizable polymer
with a low-molar-mass diluent depend on both, the diluent
fraction and the crystal thickness. A differentiation of the two
factors can be achieved by temperature-dependent SAXS
experiments. A corresponding study, complemented by DSC,
dilatometry, microscopy and AFM-imaging, was carried out for
mixtures of a poly(ethylene-co-octene) with
n-C16H34,
c-C16H32
and methyl-anthracene, respectively. All diluents lead for a
constant crystal thickness to melting point depressions in
agreement with Raoult's law. On the other hand, the effect of
the diluents on the thickness of the crystals formed at a fixed
crystallization temperature varies. While in the presence of the
two alkanes thicker crystals form, no effect arises for the
methyl-anthracene—as was previously found for the
octene-co-units. We consider these observations as a further
support for our view that polymer crystallization follows a
multi-stage route which includes a passage through an
intermediate mesomorphic phase. Under such conditions crystal
thicknesses would only be affected if the diluent is still
present in the mesomorphic phase and stay invariant if the
diluent molecules are already rejected when this intermediate
phase forms. 相似文献
24.
In this paper we show that the parabolic problem associated with elliptic operators A having coefficients in has the property of maximal -regularity.
RID="h1"
ID="h1"In Memoriam Philippe Bénilan 相似文献
25.
Marco L. Hennrich Shabaz Mohammed A. F. Maarten Altelaar Albert J. R. Heck 《Journal of the American Society for Mass Spectrometry》2010,21(12):1957-1965
Here, we explore a de novo sequencing strategy in which we combine Lys-N protein digestion with differential isotopic dimethyl
labeling to facilitate the (de novo) identification of multiply charged peptides in ESI-MS, both under CID and ETD conditions.
For a large fraction of the Lys-N generated peptides, all primary amines are present at the N-terminal lysine, enabling specific
labeling of the N-terminus. Differential derivatization of only the peptide N-terminus in combination with the simultaneous
fragmentation of the corresponding isotopologues allows the straightforward distinction of N-terminal fragments from C-terminal
and internal fragments. Furthermore, also singly and multiply charged N-terminal fragments can easily be distinguished due
to the mass differences of the isotope labeled fragment pairs. As a proof of concept, we applied this approach to proteins
isolated from an avocado fruit, and were able to partially de novo sequence and correctly align, with green plant homologues,
a previously uncharacterized avocado ascorbate peroxidase. 相似文献
26.
We report observation and control of the spatial-spectral distributions of coherent, dynamic Rabi sideband radiation. The Rabi sidebands result from the interaction of a shaped picosecond probe laser of intensity 10(10) W cm(-2), with neutral excited atomic oxygen generated in a laser-induced microplasma. The spatial-spectral distribution is measured and compared for picosecond laser pulses having either an asymmetric temporal shape or a Gaussian temporal shape. The resulting spatial-spectral distributions are in quantitative agreement with theoretical predictions that account for the radial intensity distribution of the picosecond probe pulse. 相似文献
27.
Michael Heck Klaus Blaum R. Burcu Cakirli Daniel Rodr??guez Lutz Schweikhard Stefan Stahl Marta Ubieto-D??az 《Hyperfine Interactions》2011,199(1-3):347-355
Dipolar and single-phase two-electrode quadrupolar detection schemes have been investigated at a Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) setup built for the KATRIN experiment at the Max-Planck-Institute for Nuclear Physics (MPIK) in Heidelberg. We present first experimental results of 7Li?+? signals from a cylindrical Penning trap configuration for both detection schemes. While the prominent signal of the conventional dipolar detection scheme marks the reduced cyclotron frequency, the main signal for the quadrupolar detection appears at the sum of the reduced cyclotron frequency and the magnetron frequency. For ideal trapping fields, this sum frequency equals the ion cyclotron frequency ?? c ?=?qB/(2??m). Sidebands due to the combined motions of the cyclotron mode and magnetron mode are observed by quadrupolar detection which allows the determination of the respective combinations of eigenfrequencies. 相似文献
28.
This article explores the following question: What does it mean to enact curriculum? In order to do so, it offers a conceptualization of the enacted curriculum and situates it within a curriculum policy, design, and enactment system. The system depicts the formal and operational domains in which curricular aims and objectives are developed and curriculum plans formulated and enacted. The authors situate the enacted mathematics curriculum in the operational part of the system and define it as the interactions between teachers and students around mathematical tasks of a lesson and collection of lessons, but argue that understanding what it means to enact curriculum involves examining the many places within the system that curricular elements are translated and transformed. The authors describe each of the articles in this special issue with respect to the framework. 相似文献
29.
30.
Pagels N Albrecht O Görlitz D Rogachev AY Prosenc MH Heck J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(15):4166-4176
The paramagnetic dinuclear complexes 1,8-bis(cobaltocenyl)naphthalene (2) and 1,8-bis[(pentamethyl-η(5)-cyclopentadienyl)(η(5)-cyclopentadiendiyl)cobalt(II)]naphthalene (4) were synthesized. The molecular structures were characterized by X-ray structure analysis and consisted of two cobaltocenes linked through a distorted naphthalene clamp. Electronic interactions between the two cobalt atoms were observed by cyclic voltammetric studies. Superconducting quantum interference device (SQUID) measurements of the pure compounds and diluted in their diamagnetic iron derivatives, as well as variable-temperature NMR spectroscopy experiments in solution are presented. Magnetic measurements revealed an antiferromagnetic coupling of the electrons in complexes 2 and 4. From NMR spectroscopy experiments, Curie behavior in the temperature range from -60 to +60 °C can be deduced. The electronic structure and magnetic behavior is supported by results of broken-symmetry DFT and multireference calculations along with UV/Vis spectroscopic data, which revealed an intramolecular through space π-π interaction between the cobaltocene units. 相似文献