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181.
Summary An on-line push-pull sampling technique has been developed for continuous analysis of proteins of molecular weight from 5.7
to 67 kDa. The characteristics of the system include gradient elution with a total cycle time of 21 min, membrane stability,
unattended automatic operation, and adjustment of the sampling mode and extraction fraction (the ratio of the concentration
of analyte in the dialysate to that in the sample) by varying the effective dialysis length. The push and pull flow rates
were adjusted in a manner which enabled three different modes of operation. When push-pull microdialysis was compared with
conventional microdialysis sampling, significantly higher extraction fractions were obtained for all five model proteins studied.
The technique has been applied to the quantification of proteins in cell samples. On-line fractionation enabled complementary
MS identification of the proteins present. 相似文献
182.
Daniela Rusanova Kevin J. Pike Ingmar Persson Ray Dupree Mats Lindberg John V. Hanna Oleg N. Antzutkin Willis Forsling 《Polyhedron》2006,25(18):3569-3580
Polycrystalline octa-nuclear copper(I) O,O′-di-i-propyl- and O,O′-di-i-amyldithiophosphate cluster compounds, {Cu8[S2P(OR)2]6(μ8-S)} where R = iPr and iAm, were synthesized and characterized by 31P CP/MAS NMR at 8.46 T and static 65Cu NMR at multiple magnetic field strengths (7.05, 9.4 and 14.1 T). The symmetries of the electronic environments around the P sites were estimated from the 31P chemical shift anisotropy (CSA) parameters, δaniso and η. Analyses of the 65Cu chemical shift and quadrupolar splitting parameters for these compounds are presented with the data being compared to those for the analogous octa-nuclear cluster compounds with R = nBu and iBu. The 65Cu transverse relaxation for the copper sites in {Cu8[S2P(OiPr)2]6(μ8-S)} and {Cu8[S2P(OiAm)2]6(μ8-S)} was found to be very different, with a relaxation time, T2, of 590 μs (Gaussian) and 90 μs (exponential), respectively. The structures of {Cu4[S2P(OiPr)2]4} and {Cu8[S2P(OiPr)2]6(μ8-S)} cluster compounds in the liquid- and the solid-state were studied by Cu K-edge EXAFS. The disulfide, [S2P(OiAm)2]2, was obtained and characterized by 31P{1H} NMR. The interactions of the disulfide and of the potassium O,O′-di-i-amyldithiophosphate salt with the surfaces of synthetic chalcocite (Cu2S) were probed using solid-state 31P NMR spectroscopy and only the presence of copper(I) dithiophosphate species with the {Cu8[S2P(OiAm)2]6(μ8-S)} structure was observed. 相似文献
183.
Martin Lindberg Andris Vaivads Savvas Raptis Per-Arne Lindqvist Barbara L. Giles Daniel Jonathan Gershman 《Entropy (Basel, Switzerland)》2022,24(6)
We use Magnetospheric Multiscale (MMS) data to study electron kinetic entropy per particle across Earth’s quasi-perpendicular bow shock. We have selected 22 shock crossings covering a wide range of shock conditions. Measured distribution functions are calibrated and corrected for spacecraft potential, secondary electron contamination, lack of measurements at the lowest energies and electron density measurements based on plasma frequency measurements. All crossings display an increase in electron kinetic entropy across the shock being positive or zero within their error margin. There is a strong dependence of on the change in electron temperature, , and the upstream electron plasma beta, . Shocks with large have large . Shocks with smaller are associated with larger . We use the values of , and density change to determine the effective adiabatic index of electrons for each shock crossing. The average effective adiabatic index is . 相似文献
184.
M. Ohrlander T. Lindberg A. Wirsn A.‐C. Albertsson 《Journal of polymer science. Part A, Polymer chemistry》1999,37(11):1651-1657
Acrylamide was graft polymerized onto the surface of a biodegradable semicrystalline polyester, poly(ε‐caprolactone). Electron beam irradiation at a dose of 5 Mrad was used to generate initiating species in the polyester. The degradation in vitro at pH 7.4 and 37°C in a phosphate buffer solution was studied for untreated, irradiated and acrylamide‐grafted polymers. In the case of poly(ε‐caprolactone), all materials showed similar behavior in terms of weight loss. No significant decrease in weight was observed up to 40 weeks, after which the loss of weight accelerated. The main differences in degradation behavior were found for the average molecular weights, M̄n and M̄w. Virgin poly(ε‐caprolactone) maintained M̄n and M̄w up to about 40 weeks, whereas the irradiated and grafted poly(ε‐caprolactone) showed similar continuous declines in M̄n and M̄w throughout the degradation period. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1651–1657, 1999 相似文献
185.
Sukhomlinov Dmitry Tesfaye Fiseha Hellstén Niko Lindberg Daniel Taskinen Pekka 《Journal of Solid State Electrochemistry》2018,22(4):959-972
Journal of Solid State Electrochemistry - Thermodynamic properties of solid phases in the Cu–O–Al2O3 system were measured by means of the EMF method with oxygen concentration galvanic... 相似文献
186.
The FTIR spectra of solid resin-free samples of chemically modified Norway spruce wood were recorded. Correlations were noted between spectral and hydrogen bond structure, chemical modification, fibre crystallinity and macroscopic softening point. 相似文献
187.
Jakob Lindberg Johan Nilvebrant Per-ke Nygren Fredrik Lehmann 《Molecules (Basel, Switzerland)》2021,26(19)
We review drug conjugates combining a tumor-selective moiety with a cytotoxic agent as cancer treatments. Currently, antibody-drug conjugates (ADCs) are the most common drug conjugates used clinically as cancer treatments. While providing both efficacy and favorable tolerability, ADCs have limitations due to their size and complexity. Peptides as tumor-targeting carriers in peptide-drug conjugates (PDCs) offer a number of benefits. Melphalan flufenamide (melflufen) is a highly lipophilic PDC that takes a novel approach by utilizing increased aminopeptidase activity to selectively increase the release and concentration of cytotoxic alkylating agents inside tumor cells. The only other PDC approved currently for clinical use is 177Lu-dotatate, a targeted form of radiotherapy combining a somatostatin analog with a radionuclide. It is approved as a treatment for gastroenteropancreatic neuroendocrine tumors. Results with other PDCs combining synthetic analogs of natural peptide ligands with cytotoxic agents have been mixed. The field of drug conjugates as drug delivery systems for the treatment of cancer continues to advance with the application of new technologies. Melflufen provides a paradigm for rational PDC design, with a targeted mechanism of action and the potential for deepening responses to treatment, maintaining remissions, and eradicating therapy-resistant stem cells. 相似文献
188.
Possible applications of solid-state NMR in studies on polypeptides and proteins are presented. Several examples of 13-C CP/MAS NMR spectra are discussed in relation to model compounds and polypeptides from various sources. A comparison is made with vibrational spectroscopic methods. It is concluded that the CP/MAS NMR method is especially useful in elucidating secondary structures in the unperturbed state, and, thus, may also be useful in the study of various conditions involving the disturbance of biochemical equilibria (e.g. the skin disease psoriasis and β-fibrilloses). In these cases the NMR method is more elucidative than vibrational spectroscopy. However, owing to the fact that multiple spectral scans must be performed, it is very time consuming. It therefore appears that high resolution Fourier transform infra-red spectroscopy is a complementary method, but not as informative regarding structural details in secondary structures. Combining both methods together provides a powerful tool for structure analysis. 相似文献
189.
Ernst Lindberg 《Zeitschrift für Physik A Hadrons and Nuclei》1929,56(5-6):402-404
190.
Erik Lindberg 《Nonlinear dynamics》2006,44(1-4):219-224
Chaotic systems are observed everywhere. Electronic circuit analogues based on the differential equations of the models for
the chaotic systems are often used to study the nature of chaotic systems. This tutorial is an attempt to classify electronic
chaotic oscillators according to the mechanism behind the chaotic behavior, e.g. one group is based on the sudden interrupt
of inductive currents, another group is based on the sudden parallel coupling of capacitors with different voltages, and a
third group may be based on multiplication of signals. An example of chaos based on disturbance of integration is discussed
in details.
Paper presented at ‘NDES 2004‘, Evora, Portugal, May 2004.
IEEE life member. 相似文献