全文获取类型
收费全文 | 245篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
化学 | 155篇 |
力学 | 7篇 |
数学 | 32篇 |
物理学 | 55篇 |
出版年
2022年 | 3篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 16篇 |
2007年 | 17篇 |
2006年 | 22篇 |
2005年 | 10篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 3篇 |
1986年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1978年 | 7篇 |
1969年 | 2篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1961年 | 1篇 |
1959年 | 3篇 |
1958年 | 2篇 |
1939年 | 1篇 |
1938年 | 2篇 |
1937年 | 3篇 |
1933年 | 1篇 |
1931年 | 3篇 |
1930年 | 1篇 |
1929年 | 2篇 |
1926年 | 1篇 |
1919年 | 2篇 |
1918年 | 1篇 |
1917年 | 1篇 |
1909年 | 3篇 |
1900年 | 1篇 |
排序方式: 共有249条查询结果,搜索用时 14 毫秒
91.
Einar Lindholm 《Zeitschrift für Physik A Hadrons and Nuclei》1939,113(9-10):596-606
92.
93.
Ohne Zusammenfassung 相似文献
94.
95.
G. Tammann A. B. P. Leme Manne Siegbahn Einar Friman Beckmann Riesenfeld E. Posejpal und W. Thörner 《Fresenius' Journal of Analytical Chemistry》1919,58(8):354-356
Ohne Zusammenfassung 相似文献
96.
97.
Hollow fibre based liquid-phase microextraction (LPME) using fatty oils and essential oils as the organic phase was evaluated to develop sample preparation technology eliminating the use of hazardous organic solvents. Basic drugs were extracted from different aqueous samples (0.2 to 1 mL) through approximately 15 microL of either almond oil, arachis oil, olive oil, soy-bean oil, anise oil, fennel oil, lavender oil, or peppermint oil (organic phase) immobilised within the pores of a polypropylene hollow fibre and into 20 microL of 10 mM HCOOH (acceptor phase) present inside the lumen of the hollow fibre. The extraction performance of the essential oils was comparable with the solvents normally used in LPME (dihexyl ether, n-octanol, and dodecyl acetate) in terms of extraction recovery and extraction speed. Whereas all essential oils tested were compatible with human urine, only anise oil was successful for plasma. The fatty oils provided lower recoveries than the essential oils due to higher viscosity, but all the fatty oils were compatible both with urine and plasma samples. In spite of the multi-component nature of the oils tested, they were not found to seriously contaminate the acceptor phases during extraction. In conclusion, fatty oils and essential oils may serve as alternative organic phase in LPME, eliminating the use of hazardous organic solvents. 相似文献
98.
The micellar radii and the electron density of the polar and non polar regions in micelles have been determined by a small-angle X-ray scattering (SAXS) technique originally designed by Luzzati et al. and subsequently modified by Larsson. The model employed shows the micellar structure as consisting of a liquid hydrocarbon core and a polar shell comprising the ionic polar head groups plus the diffuse double layer of bound counterions. The shortcomings of the model are discussed in the light of a recent paper by Hayter & Penfold providing general support for the parameters obtained and the conclusions drawn.The results found for the binary aqueous systems of potassium hexanoate, sodium octanoate and sodium decanoate describes the micelles as having quite an open structure with a rather small truly anhydrous hydrocarbon core. The low electron density contrast found between the polar layer and the surrounding media prevents us from drawing conclusions as to the absolute value of the polar (total) micellar radius, although the changes in this radius seem relevant. The octane-1, 8-diol is found to partly penetrate the hydrocarbon core but mostly to reside in the polar shell or to remain in the bulk solvent. Both the cyclohexane and carbon tetrachloride seem to be solubilized in the interior of the micelle, the former causing a considerable swelling of the micelle. 相似文献
99.
Well defined a.c. polarographic waves are obtained in the presence of certain ionic surfactants. The current is brought about by an electron-transfer through the adsorbed layer, probably by the formation of a bridge which accelerates the electrontransfer between the electrode and the depolarizer. The resulting a.c. wave is accompanied by a d.c. polarographic step and the height of the wave increases proportionally to the bulk concentration of the depolarizer. In contrast to ordwary a.c, waves, the a.c. current of these waves increases linearly with increasing height of the mercury column above the capillary. 相似文献
100.
Reduced basis methods are particularly attractive to use in order to diminish the number of degrees-of-freedom associated with the approximation to a set of partial differential equations. The main idea is to construct ad hoc basis functions with a large information content. In this Note, we propose to develop and analyze reduced basis methods for simulating hierarchical flow systems, which is of relevance for studying flows in a network of pipes, an example being a set of arteries or veins. We propose to decompose the geometry into generic parts (e.g., pipes and bifurcations), and to construct a reduced basis for these generic parts by considering representative geometric snapshots. The global system is constructed by gluing the individual basis solutions together via Lagrange multipliers. To cite this article: Y. Maday, E.M. Rønquist, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 195–200. 相似文献