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51.
Jürgen Vogt Rolf-Horst Flagmeyer Johannes Heitmann Dietmar Lehmann Tilo Reinert Steffen Jankuhn Daniel Spemann Wolfgang Tröger Tilman Butz 《Mikrochimica acta》2000,133(1-4):105-111
The high-energy ion nanoprobe LIPSION at the University of Leipzig has been operational since October 1998. The ultrastable
single ended 3.5 MV SINLETRONTM accelerator supplies the H+ or He+ ion beam. A magnetic scanning system moves the focused beam across the sample. At present, a resolution of 150 nm in the
low current mode and 300 nm at 5 pA could be achieved.
The UHV grade experimental chamber is equipped with electron-, energy dispersive X-ray-, and particle detectors. They can
be used simultaneously to analyse the sample by means of PIXE (particle induced X-ray emission), RBS (Rutherford backscattering)
and in the case of thin samples STIM (scanning transmission ion microscopy).
A goniometer allows the application of channeling measurements in single crystals in combination with these methods.
The detection limits depend on the elements to be analysed and range from (1000⋯1) μg/g relative and (1⋯0.01) pg absolute.
The analysis is nondestructive, but the sample has to be vacuum resistant. Applications of the nanoprobe in the field of semiconductor
research, biomedicine, and archaeology will be described. 相似文献
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We discuss the recently proposed multicanonical multigrid Monte Carlo method and apply it to the scalar
4 on a square lattice. To investigate the peformance of the new algorithm at the field-driven first-order phase transitions between the two ordered phases we carefully analyze the autocorrelations of the Monte Carlo process. Compared with standard mlticanonical simulations a real-time improvement of about one order of magnitude is established. The interface tension between the two ordered phases is extracted from highstatistics histograms of the magnetization applying histogram reweighting techniques. 相似文献
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The recent achievement of Bose–Einstein condensation of chromium atoms [1] has opened longed-for experimental access to a
degenerate quantum gas with long-range and anisotropic interaction. Due to the large magnetic moment of chromium atoms of
6 μB, in contrast to other Bose–Einstein condensates (BECs), magnetic dipole-dipole interaction plays an important role in a chromium
BEC. Many new physical properties of degenerate gases arising from these magnetic forces have been predicted in the past and
can now be studied experimentally. Besides these phenomena, the large dipole moment leads to a breakdown of standard methods
for the creation of a chromium BEC. Cooling and trapping methods had to be adapted to the special electronic structure of
chromium to reach the regime of quantum degeneracy. Some of them apply generally to gases with large dipolar forces. We present
here a detailed discussion of the experimental techniques which are used to create a chromium BEC and allow us to produce
pure condensates with up to 105 atoms in an optical dipole trap. We also describe the methods used to determine the trapping parameters. 相似文献
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Kenichi Ataka Dr. Tilman Kottke Dr. Joachim Heberle Prof. Dr. 《Angewandte Chemie (International ed. in English)》2010,49(32):5416-5424
New techniques in vibrational spectroscopy are promising for the study of biological samples as they provide exquisite spatial and/or temporal resolution with the benefit of minimal perturbation of the system during observation. In this Minireview we showcase the power of modern infrared techniques when applied to biological and biomimetic systems. Examples will be presented on how conformational changes in peptides can be traced with femtosecond resolution and nanometer sensitivity by 2D IR spectroscopy, and how surface‐enhanced infrared difference absorption spectroscopy can be used to monitor the effect of the membrane potential on a single proton‐transfer step in an integral membrane protein. Vibrational spectra of monolayers of molecules at basically any interface can be recorded with sum‐frequency generation, which is strictly surface‐sensitive. Chemical images are recorded by applying scanning near‐field infrared microscopy at lateral resolutions better than 50 nm. 相似文献
60.
Sebastian Bock Remi Lafaye Tilman Plehn Michael Rauch Dirk Zerwas Peter M. Zerwas 《Physics letters. [Part B]》2010
Higgs couplings can be affected by physics beyond the Standard Model. We study modifications through interactions with a hidden sector and in specific composite Higgs models accessible at the LHC. Both scenarios give rise to congruent patterns of universal, or partially universal, shifts. In addition, Higgs decays to the hidden sector may lead to invisible decay modes which we also exploit. Experimental bounds on such potential modifications will measure the concordance of an observed Higgs boson with the Standard Model. 相似文献