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141.
K-G Dietrich D. H. H. Hoffmann H. Wahl C. R. Haas H. Kunze W. Brandenburg R. Noll 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1990,16(4):229-230
The energy loss of heavy ions with an energy of 1.4 MeV/u in a hydrogen plasma has been measured. A 20 cm longz-pinch has been used as plasma target. Our data show a strong enhancement of the stopping power of the plasma compared to that of a cold gas with equal density. The results completely confirm the predictions of the standard stopping power model. 相似文献
142.
G. Meinrath P. Volke C. Helling E. G. Dudel B. J. Merkel 《Fresenius' Journal of Analytical Chemistry》1999,364(3):191-202
Interpretation of environmental behavior of uranium is based on several steps of data analysis and statistical inference.
First step is sampling and analyzing of uranium in field samples by routine laboratory methods. Such methods have to fulfill
multiple requirements like robustness, efficiency, low detection limit and precision. A comparison of different approaches
in assigning uncertainty to experimentally obtained analytical data shows that classical error estimation is not significantly
inferior to more sophisticated modern techniques like inverse regression or orthogonal regression. A second step is the correlation
of analytical data with current state of insight into environmental behavior of uranium. Such a correlation furthers the choice
of adequate geochemical models and quality of geochemical data base for subsequent detailed analysis, e.g. by geochemical
modeling. An appraisal of the individual steps in this complex analysis is given on the basis of statistical procedures for
calibration and an EH-pH diagram of uranium for atmospheric conditions.
Received: 30 July 1998 / Revised: 18 November 1998 / Accepted: 26 November 1998 相似文献
143.
144.
145.
E. Riegler H. Zellner und K. Dietrich 《Fresenius' Journal of Analytical Chemistry》1902,41(8):508-509
Ohne Zusammenfassung 相似文献
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147.
M. Braun-Unkhoff N. Hansen M. Dietrich T. Methling K. Moshammer B. Yang 《Proceedings of the Combustion Institute》2021,38(2):2387-2395
This paper concerns itself with the entanglement of the high-temperature oxidation chemistry of n-heptane and iso-butanol in flames fueled by their mixtures. While in many cases the chemistries of the individual fuel components do not interact in mixture flames, in this work, we revealed interactions between the individual species pools originating from n-heptane and iso-butanol oxidation. In a coordinated experimental and modeling effort, chemical structures of three low-pressure premixed flames fueled by different blends of n-heptane and iso-butanol were determined using flame-sampling molecular-beam mass spectrometry with synchrotron-based single-photon ionization and chemical kinetic modeling. The chemical kinetic model, which is based on the reaction set that was used previously [Braun-Unkhoff et al., Proc. Combust. Inst., 2017, 36, 1311–1319], was now extended by an n-heptane sub-mechanism. The overall good performance of the model allows for an extraction of chemically relevant information that highlights the entanglement between the individual fuel-specific species pools. For example, it was shown that methyl radicals, in part from iso-butanol oxidation (i.e., from the decomposition of α-iso-butanol radicals) can participate in n-heptane consumption processes through H-abstraction reactions. Further interactions are related to the formation of the methylallyl radical and aromatics formation. The relevance of such interactions is also discussed regarding the formation of oxygenated byproducts. 相似文献
148.
Siddappa Patil Karolin Dietrich Anthony Deally Brendan Gleeson Helge Müller‐Bunz Francesca Paradisi Matthias Tacke 《Helvetica chimica acta》2010,93(12):2347-2364
From the reaction of 1H‐imidazole ( 1a ), 4,5‐dichloro‐1H‐imidazole ( 1b ), 1H‐benzimidazole ( 1c ), 1‐methyl‐1H‐imidazole ( 1d ), and 1‐methyl‐1H‐benzimidazole ( 1f ) with methyl 4‐(bromomethyl)benzoate ( 2 ), symmetrically and nonsymmetrically 4‐(methoxycarbonyl)benzyl‐substituted N‐heterocyclic carbene (NHC) precursors, 3a – 3f , were synthesized. These NHC precursors were then reacted with silver(I) acetate (AgOAc) to yield the NHC–silver acetate complexes (acetato‐κO){1,3‐bis[4‐(methoxycarbonyl)benzyl]imidazol‐2‐ylidene}silver ( 4a ), (acetato‐κO){4,5‐dichloro‐1,3‐bis[4‐(methoxycarbonyl)benzyl]‐2,3‐dihydro‐1H‐imidazol‐2‐yl}silver ( 4b ), (acetato‐κO){1,3‐bis[4‐(methoxycarbonyl)benzyl]‐2,3‐dihydro‐1H‐benzimidazol‐2‐yl}silver ( 4c ), (acetato‐κO){1‐[4‐(methoxycarbonyl)benzyl]‐3‐methyl‐2,3‐dihydro‐1H‐imidazol‐2‐yl}silver ( 4d ), (acetato‐κO){4,5‐dichloro‐1‐[4‐(methoxycarbonyl)benzyl]‐3‐methyl‐2,3‐dihydro‐1H‐imidazol‐2‐yl}silver ( 4e ), and (acetato‐κO){1‐[4‐(methoxycarbonyl)benzyl]‐3‐methyl‐2,3‐dihydro‐1H‐benzimidazol‐2‐yl}silver ( 4f ), respectively. The three NHC–AgOAc complexes 4a, 4c , and 4d were characterized by single‐crystal X‐ray diffraction. All compounds studied in this work were preliminarily screened for their antimicrobial activities in vitro against Gram‐positive bacteria Staphylococcus aureus, and Gram‐negative bacteria Escherichia coli using the qualitative disk‐diffusion method. All NHC–AgOAc complexes exhibited weak‐to‐medium antibacterial activity with areas of clearance ranging from 4 to 7 mm at the highest amount used, while the NHC precursors showed significantly lower activity. In addition, NHC–AgOAc complexes 4a and 4b , and 4d – 4f exhibited in preliminary cytotoxicity tests on the human renal‐cancer cell line Caki‐1 medium‐to‐high cytotoxicities with IC50 values ranging from 3.3±0.4 to 68.3±1 μM . 相似文献
149.
Strong fluence dependence of photodesorption cross sections is observed in femtosecond laser photodesorption of NO from (NO)2 on silver nanoparticles, in contrast to femtosecond photodesorption on bulk metals. The time scale of excitation buildup is found to be equal or less than the pulse duration of ~100 fs; NO translational energies are independent of fluence and pulse duration. We propose a nanoparticle-specific nonlinear mechanism in which, due to confinement, strongly nonthermal hot-electron distributions are maintained during the femtosecond pulses, enhancing the normal desorption pathway. 相似文献
150.
Generic relevant deformations of Einstein's gravity theory contain additional degrees of freedom that have a multifaceted stabilization dynamics on curved spacetimes. We show that these relevant degrees of freedom are self-protected against unitarity violations by the formation of classical field lumps that eventually merge to a new background geometry. The transition is heralded by the massive decay of the original vacuum and evolves through a strong coupling regime. This process fits in the recently proposed classicalization mechanism and extends it further to free field dynamics on curved backgrounds. 相似文献