全文获取类型
收费全文 | 165篇 |
免费 | 3篇 |
国内免费 | 3篇 |
专业分类
化学 | 79篇 |
晶体学 | 1篇 |
力学 | 7篇 |
数学 | 40篇 |
物理学 | 44篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 12篇 |
2005年 | 13篇 |
2004年 | 3篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
排序方式: 共有171条查询结果,搜索用时 78 毫秒
1.
2.
Chava Lifshitz 《Trends in analytical chemistry : TRAC》1982,1(13):301-304
The fragmentation patterns of polyatomic ions are the source of the analytical information provided by mass spectrometry. Recent developments in the study of theoretical aspects related to unimolecular dissociations of polyatomic ions have improved our understanding of these processes. 相似文献
3.
T. Saraidarov R. Reisfeld A. Sashchiuk E. Lifshitz 《Journal of Sol-Gel Science and Technology》2003,26(1-3):533-540
PbS nanocrystals (NCs) ranging between 4–8 nm were incorporated into Zirconium-Silica-Urethane (ZSUR) matrix obtained by the sol-gel method. The sizes of the particles were controlled by temperature treatment and by concentration of PbS in ZSUR matrix. The sizes of PbS NCs were determined by TEM measurements. The quantum size effect could also be extracted from optical absorption and photoluminescence spectra. The new matrix allows incorporation of up to 40% PbS forming a characteristic structure of dendrite by reacting lead acetate with ammonium thiocyanate in sol-gel matrix. The sol precursors of the matrix for Zirconium-Silica-Urethane contained zirconium oxide (ZrO2) matrix solution, tetramethoxysilane (TMOS), 3-glycid oxypropyl trimethoxysilane (GLYMO) and polyethylene urethane silane (PEUS) synthesized separately. The ZrO2 matrix solution was obtained from zirconium n-tetrapropoxide in propanol and acetic acid was used as a chelating agent to stabilize the zirconium oxide precursor. 相似文献
4.
Kinetic energy releases (KERs) in unimolecular fragmentations of singly and multiply charged ions provide information concerning ion structures, reaction energetics and dynamics. This topic is reviewed covering both early and more recent developments. The subtopics discussed are as follows: (1) introduction and historical background; (2) ion dissociation and kinetic energy release: kinematics; potential energy surfaces; (3) the kinetic energy release distribution (KERD); (4) metastable peak observations: measurements on magnetic sector and time-of-flight instruments; energy selected results by photoelectron photoion coincidence (PEPICO); (5) extracting KERDs from metastable peak shapes; (6) ion structure determination and reaction mechanisms: singly and multiply charged ions; biomolecules and fullerenes; (7) theoretical approaches: phase space theory (PST), orbiting transition state (OTS)/PST, finite heat bath theory (FHBT) and the maximum entropy method; (8) exit channel interactions; (9) general trends: time and energy dependences; (10) thermochemistry: organometallic reactions, proton-bound clusters, fullerenes; and (11) the efficiency of phase space sampling. 相似文献
5.
Wan Yong Feng Moshe Goldenberg Chava Lifshitz 《Journal of the American Society for Mass Spectrometry》1994,5(8):695-703
Thermal reactions of proton-bound dimers, (CH3CN)2H +, (CH3OCH3)2H +, and (CH3COCH3)2H+, were studied using a selected ion flow tube. Reactions observed include association, switching, and proton transfer. The association channel was observed only for base molecules that had hydrogen bonding protons such as NH3, CH3NH2, (CH3)2NH, and CH3OH. An association-insertion mechaniSoc was proposed in which the central proton of the symmetrically bound dimers is replaced by a protonated base, for example, NH 4 + . These reactions are relatively slow, which demonstrates a central barrier along the potential energy surface. Ether-containing dimers do not demonstrate this insertion reaction, except for diethers, for example, CH3OCH2CH2OCH3, which can form stable bicyclic structures. Dimers such as (HCOOH)2H+, which possess hydrogen bonding protons in the periphery, undergo switching reactions with ammonia and no insertion. 相似文献
6.
7.
Kamel Abbas Izabela Cydzik Riccardo Del Torchio Massimo Farina Efrat Forti Neil Gibson Uwe Holzwarth Federica Simonelli Wolfgang Kreyling 《Journal of nanoparticle research》2010,12(7):2435-2443
Industrially manufactured titanium dioxide nanoparticles have been successfully radiolabelled with 48V by irradiation with a cyclotron-generated proton beam. Centrifugation tests showed that the 48V radiolabels were stably bound within the nanoparticle structure in an aqueous medium, while X-ray diffraction indicated
that no major structural modifications to the nanoparticles resulted from the proton irradiation. In vitro tests of the uptake
of cold and radiolabelled nanoparticles using the human cell line Calu-3 showed no significant difference in the uptake between
both batches of nanoparticles. The uptake was quantified by Inductively Coupled Plasma Mass Spectrometry and high resolution
γ-ray spectrometry for cold and radiolabelled nanoparticles, respectively. These preliminary results indicate that alterations
to the nanoparticles’ properties introduced by proton bombardment can be controlled to a sufficient extent that their further
use as radiotracers for biological investigations can be envisaged and elaborated. 相似文献
8.
9.
10.
We present several efficient dynamic data structures for point-enclosure queries, involving convex fat objects in
or
. Our planar structures are actually fitted for a more general class of objects – (β,δ)-covered objects – which are not necessarily convex, see definition below. These structures are more efficient than alternative known structures, because they exploit the fatness of the objects. We then apply these structures to obtain efficient solutions to two problems: (i) finding a perfect containment matching between a set of points and a set of convex fat objects, and (ii) finding a piercing set for a collection of convex fat objects, whose size is optimal up to some constant factor. 相似文献