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排序方式: 共有1906条查询结果,搜索用时 31 毫秒
971.
Rennie EE Boulanger AM Mayer PM Holland DM Shaw DA Cooper L Shpinkova LG 《The journal of physical chemistry. A》2006,110(28):8663-8675
The valence shell photoelectron spectrum, threshold photoelectron spectrum, and threshold photoelectron photoion coincidence (TPEPICO) mass spectra of acetone have been measured using synchrotron radiation. New vibrational progressions have been observed and assigned in the X 2B2 state photoelectron bands of acetone-h6 and acetone-d6, and the influence of resonant autoionization on the threshold electron yield has been investigated. The dissociation thresholds for fragment ions up to 31 eV have been measured and compared to previous values. In addition, kinetic modeling of the threshold region for CH3* and CH4 loss leads to new values of 78 +/- 2 kJ mol(-1) and 75 +/- 2 kJ mol(-1), respectively, for the 0 K activation energies for these two processes. The result for the methyl loss channel is in reasonable agreement with, but slightly lower than, that of 83 +/- 1 kJ mol(-1) derived in a recent TPEPICO study by Fogleman et al. The modeling accounts for both low-energy dissociation channels at two different ion residence times in the mass spectrometer. Moreover, the effects of the ro-vibrational population distribution, the electron transmission efficiency, and the monochromator band-pass are included. The present activation energies yield a Delta(f)H298 for CH3CO+ of 655 +/- 3 kJ mol(-1), which is 4 kJ mol(-1) lower than that reported by Fogleman et al. The present Delta(f)H298 for CH3CO+ can be combined with the Delta(f)H298 for CH2CO (-47.5 +/- 1.6 kJ mol(-1)) and H+ (1530 kJ mol(-1)) to yield a 298 K proton affinity for ketene of 828 +/- 4 kJ mol(-1), in good agreement with the value (825 kJ mol(-1)) calculated at the G2 level of theory. The measured activation energy for CH4 loss leads to a Delta(f)H298 (CH2CO+*) of 873 +/- 3 kJ mol(-1). 相似文献
972.
Martin Brandl Michael Mayer Thomas Posnicek Dieter Falkenhagen 《Journal of magnetism and magnetic materials》2010,322(17):2454-2464
The microsphere based detoxification system (MDS) is designed for high specific toxin removal in extracorporeal blood purification using functionalized microparticles. A thin wall hollow fiber membrane filter separates the microparticle-plasma suspension from the bloodstream. For patient safety, it is necessary to have a safety system to detect membrane ruptures that could lead to the release of microparticles into the bloodstream. A non-invasive optical detection system including a magnetic trap is developed to monitor the extracorporeal venous bloodstream for the presence of released microparticles. For detection, fluorescence-labeled ferromagnetic beads are suspended together with adsorbent particles in the MDS circuit. In case of a membrane rupture, the labeled particles would be released into the venous bloodstream and partly captured by the magnetic trap of the detector.A physical model based on fluidic, gravitational and magnetic forces was developed to simulate the motion and sedimentation of ferromagnetic particles in a magnetic trap. In detailed simulation runs, the concentrations of accumulated particles under different applied magnetic fields within the magnetic trap are shown. The simulation results are qualitatively compared with laboratory experiments and show excellent accordance. Additionally, the sensitivity of the particle detection system is proofed in a MDS laboratory experiment by simulation of a membrane rupture. 相似文献
973.
974.
A. Bömer M. Auerbach C. Ellis F. Bergius W. Normann E. Hugel H. Kreis E. Roth Fr. Prall A. W. Knapp J. Klimont K. Mayer und K. B. Lehmann 《Fresenius' Journal of Analytical Chemistry》1916,55(1):65-69
Ohne Zusammenfassung 相似文献
975.
F. Mayer 《Fresenius' Journal of Analytical Chemistry》1863,2(1):225-229
Ohne Zusammenfassung 相似文献
976.
Hartwig Franzen und O. v. Mayer 《Fresenius' Journal of Analytical Chemistry》1911,50(11):669-679
Ohne Zusammenfassung(Mitteilung aus dem chemischen Institut der Universität Heidelberg.) 相似文献
977.
A. Gutbier A. Mayer J. Huber W. Schieber 《Analytical and bioanalytical chemistry》1923,62(3-4):140-141
978.
Kurt Mayer 《Colloid and polymer science》1928,44(4):315-319
Ohne Zusammenfassung 相似文献
979.
A. Mayer 《Mathematische Annalen》1871,3(3):435-452
Ohne Zusammenfassung 相似文献
980.
Th. von Fellenberg Leo Mayer und C. W. Spiers 《Fresenius' Journal of Analytical Chemistry》1922,61(8-9):356-357
Ohne Zusammenfassung 相似文献