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91.
92.
93.
Coclass theory can be used to define infinite families of finite p-groups of a fixed coclass. It is conjectured that the groups in one of these infinite families all have isomorphic mod-p cohomology rings. Here we prove that almost all groups in one of these infinite families have equivalent Quillen categories. We also show how the Quillen categories of the groups in an infinite family are connected to the Quillen category of their associated infinite pro-p-group of finite coclass. 相似文献
94.
Zoran Andjelkovic Shailen Bharadia Bettina Sommer Manuel Vogel Wilfried N?rtersh?user 《Hyperfine Interactions》2010,196(1-3):81-91
The extremely strong fields that exist around the nuclei of few-electron heavy ions drastically change the properties of the electronic system such as energy level spacings, lifetimes and magnetic moments. In turn, the electrons serve as sensitive probes for nuclear properties such as size, magnetic moment and spatial distribution of charge and magnetization. The energies of their forbidden fine and hyperfine structure transitions strongly depend on the nuclear charge and shift from microwave domains in or close to the optical domain. Thus, they become accessible for laser spectroscopy and its potentially high precision. A number of such measurements have been performed in storage rings and electron beam ion traps, and have yielded results with relative accuracies in the permille region. We present here an experiment under development at GSI Darmstadt which aims to significantly increase the accuracy by employing charged particle traps which allow to slow the ion motion nearly to rest, thus reducing Doppler effects and increasing the possible accuracy to the more than ppm region. 相似文献
95.
Schausberger SE Heise B Maurer C Bernet S Ritsch-Marte M Stifter D 《Optics letters》2010,35(24):4154-4156
We propose a full-field low-coherence interference (LCI) microscope that can provide different contrast modes using Fourier-plane filtering by means of a spatial light modulator. By altering the phase and spatial frequencies of the backreflected wavefront from the sample arm of the interferometer, we are able to change the contrast in the depth-resolved LCI images. We demonstrate that different types of contrast modes, such as, e.g., spiral phase contrast, can successfully be emulated to provide specific enhancement of internal structures and edges and to reveal complementary details within the samples under investigation. 相似文献
96.
Bomke S Seiwert B Dudek L Effkemann S Karst U 《Analytical and bioanalytical chemistry》2009,393(1):247-256
A liquid chromatography (LC)/mass spectrometry method was developed for the determination of selected biogenic amines in various
fish and other food samples. It is based on a precolumn derivatization of the amines with succinimidylferrocenyl propionate
under formation of the respective amides and their reversed-phase liquid-chromatographic separation with subsequent electrospray
ionization mass-spectrometric detection. Deuterated putescine, cadaverine, and histamine are added prior to the derivatization
as internal standards that are coeluted, thus allowing excellent reproducibility of the analysis to be achieved. Depending
on the analyte, the limits of detection were between 1.2 and 19.0 mg/kg, covering between 2 and 3 decades of linearity. The
limit of detection and the linear range for histamine are suitable for the surveillance of the only defined European threshold
for biogenic amines in fish samples. Compared with the established ortho-phthalaldehyde (OPA)/LC/fluorescence method, the
newly developed method allows an unambiguous identification of the biogenic amines by their mass spectra in addition to only
retention times, a fivefold acceleration of the separation, and independency from the sample matrix owing to the isotope-labeled
internal standards. Various fish, calamari, and salami samples were successfully analyzed with the new method and validated
with an independent OPA/LC/fluorescence method. 相似文献
97.
Schlemmer B Gatschelhofer C Pieber TR Sinner FM Buchmeiser MR 《Journal of chromatography. A》2006,1132(1-2):124-131
Monolithic columns for capillary HPLC were prepared via ring-opening metathesis polymerization (ROMP) from cis-cyclooctene (COE), tris(cyclooct-4-enyl-1-oxy)methylsilane (CL) as monomers, 2-propanol and toluene as porogens and RuCl(2)(Py)(2)(IMesH(2))(CHC(6)H(5)) (Py=pyridine, IMesH(2)=1,3-dimesityl-4,5-dihydroimidazolin-2-ylidene) as initiator within the confines of 200 microm i.d. fused silica columns. For evaluation of the novel monolithic capillary HPLC columns, a protein standard consisting of six proteins in the molecular weight range of 5800-66000 g/mol, i.e. ribonuclease A, insulin, albumin, lysozyme, myoglobin and beta-lactoglobulin, was used. Reproducibility of synthesis was checked by determining the relative standard deviation (RSD) in retention times (t(R)), which was found to be in the range of 2.9-3.9% for all analytes. Variations in polymer kinetics were realized by adding different amounts of free pyridine and had a significant influence on the monolith's morphology, the backpressure and retention times. On the contrary, variations in monomer content and COE to CL ratio showed only minor changes on these parameters. Long-term stability of 1000 runs at 50 degrees C showed excellent stability of the columns and no significant alteration in separation performance was observed in combination with slightly decreased retention times (approx. 1.6-7.2% for all analytes). 相似文献
98.
99.
Based on analytical considerations about how near-wall turbulence needs to be modified in order to reduce the momentum loss towards solid walls and to yield lower energy losses, a mechanism of turbulent drag reduction is proposed. This mechanism suggests that drag reducing flow control at high Reynolds numbers should be designed to minimize the turbulent dissipation rate. A previously published approach on how a reduction of the turbulent dissipation in the near-wall region can be achieved is analyzed further. The obtained results provide some new insight on the parameters that need to be considered when designing flow control schemes for skin friction drag reduction. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
100.
Robert Kandlbinder Robert Schupfner Otto S. Wolfbeis Bettina Zinka 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(2):187-192
The incorporation of naturally occurring thorium isotopes in human femur bones was studied by analyzing 28 bone samples. The
results show that the activity concentrations of 232Th and 230Th are in the range of the blank values resulting in an upper limit of theirs activity concentrations in human bones. The
presence of 228Th can be attributed, on the basis of model calculations, to the radioactive decay of deposited 228Ra. We conclude that thorium is not detectably incorporated into human bones. 相似文献