全文获取类型
收费全文 | 93篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 36篇 |
力学 | 2篇 |
数学 | 30篇 |
物理学 | 28篇 |
出版年
2024年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 9篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有96条查询结果,搜索用时 78 毫秒
41.
Jinkun Huang Emilio Bunel Alan Allgeier Jason Tedrow Thomas Storz J. Preston Tiffany Correll Deana Manley Troy Soukup Randy Jensen Rashid Syed George Moniz Robert Larsen Michael Martinelli Paul J. Reider 《Tetrahedron letters》2005,46(45):7831-7834
Rh(CO)2(acac)/TangPhos was found to be a highly enantioselective catalyst for asymmetric hydroformylation of norbornylene under mild conditions. Application of the protocol to the desymmetrization of other [2.2.1]-bicyclic olefins gave moderate to excellent enantioselectivity (55-92% ee). 相似文献
42.
MP Janawadkar R Baskaran R Nagendran K Gireesan N Harishkumar Rita Saha L S Vaidhyanathan J Jayapandian Y Hariharan TS Radhakrishnan 《Pramana》2002,58(5-6):1159-1164
A program has been developed and initiated at the Indira Gandhi Centre for Atomic Research (IGCAR) for the utilization of
SQUID sensors in various application areas. DC SQUID sensors based on Nb-AlO
x
-Nb Josephson junctions have been designed and developed inhouse along with associated flux-locked loop (FLL) electronics.
A compact low field SQUID magnetometer insertible in a liquid helium storage dewar has also been developed inhouse and is
in use. Efforts to build a high field SQUID magnetometer, SQUID-DAC system, are in progress. A planar gradiometric DC SQUID
sensor for non-destructive evaluation (NDE) application to be used in relatively unshielded environment has been designed
and developed. An easily portable NDE cryostat with a small lift-off distance, to be used in external locations has been designed
and tested. The magnetic field produced by a given two-dimensional current density distribution is inverted using the Fourier
transform technique. 相似文献
43.
András Hajnal István Juhász Lajos Soukup Zoltán Szentmiklóssy 《Acta Mathematica Hungarica》2011,131(3):230-274
\(f\: \cup {\mathcal {A}}\to {\rho}\) is called a conflict free coloring of the set-system\({\mathcal {A}}\)(withρcolors) if The conflict free chromatic number\(\operatorname {\chi _{\rm CF}}\, ({\mathcal {A}})\) of \({\mathcal {A}}\) is the smallest ρ for which \({\mathcal {A}}\) admits a conflict free coloring with ρ colors.
$\forall A\in {\mathcal {A}}\ \exists\, {\zeta}<{\rho} (|A\cap f^{-1}\{{\zeta}\}|=1).$
\({\mathcal {A}}\) is a (λ,κ,μ)-system if \(|{\mathcal {A}}| = \lambda\), |A|=κ for all \(A \in {\mathcal {A}}\), and \({\mathcal {A}}\) is μ-almost disjoint, i.e. |A∩A′|<μ for distinct \(A, A'\in {\mathcal {A}}\). Our aim here is to study for λ≧κ≧μ, actually restricting ourselves to λ≧ω and μ≦ω.
For instance, we prove that$\operatorname {\chi _{\rm CF}}\, (\lambda,\kappa,\mu) = \sup \{\operatorname {\chi _{\rm CF}}\, ({\mathcal {A}})\: {\mathcal {A}}\mbox{ is a } (\lambda,\kappa,\mu)\mbox{-system}\}$
? for any limit cardinal κ (or κ=ω) and integers n≧0, k>0, GCH implies
? if λ≧κ≧ω>d>1, then λ<κ +ω implies \(\operatorname {\chi _{\rm CF}}\, (\lambda,\kappa,d) <\omega\) and λ≧? ω (κ) implies \(\operatorname {\chi _{\rm CF}}\, (\lambda,\kappa,d) = \omega\);? GCH implies \(\operatorname {\chi _{\rm CF}}\, (\lambda,\kappa,\omega) \le \omega_{2}\) for λ≧κ≧ω 2 and V=L implies \(\operatorname {\chi _{\rm CF}}\, (\lambda,\kappa,\omega) \le \omega_{1}\) for λ≧κ≧ω 1;? the existence of a supercompact cardinal implies the consistency of GCH plus \(\operatorname {\chi _{\rm CF}}\,(\aleph_{\omega+1},\omega_{1},\omega)= \aleph_{\omega+1}\) and \(\operatorname {\chi _{\rm CF}}\, (\aleph_{\omega+1},\omega_{n},\omega) = \omega_{2}\) for 2≦n≦ω;? CH implies \(\operatorname {\chi _{\rm CF}}\, (\omega_{1},\omega,\omega) = \operatorname {\chi _{\rm CF}}\, (\omega_{1},\omega_{1},\omega) = \omega_{1}\), while \(MA_{\omega_{1}}\) implies \(\operatorname {\chi _{\rm CF}}\, (\omega_{1},\omega,\omega) = \operatorname {\chi _{\rm CF}}\, (\omega_{1},\omega_{1},\omega) = \omega\). 相似文献
$\operatorname {\chi _{\rm CF}}\, (\kappa^{+n},t,k+1) =\begin{cases}\kappa^{+(n+1-i)}&; \text{if \ } i\cdot k < t \le (i+1)\cdot k,\ i =1,\dots,n;\\[2pt]\kappa&; \text{if \ } (n+1)\cdot k < t;\end{cases}$
44.
45.
H. Bärwolff G. Bohm C. Dreher W. Friebel U. Gensch A. Meyer T. Naumann H. Roloff C. Spiering E. Denes L. Diosy T. Gemesy L. Jenik J. Krasznovsky Gy. Pinter I. Wagner A. V. Bannikov J. Böhm Ya. V. Grishkevich B. A. Khomenko Z. V. Krumstein Yu. P. Merekov V. I. Petrukhin K. Piska K. Safarik G. A. Shelkov L. G. Tkachev L. S. Vertogradov T. Soukup A. Valkarova S. Valkar P. Zavada V. N. Penev A. I. Shklovskaya A. K. Javrishvili A. I. Kharchilava T. A. Lomtadze L. A. Razdolskaya W. Dominik J. Gajewski S. Majewski K. Pniewska L. Ropelewski J. A. Zakrzewski RISK Collaboration 《Zeitschrift fur Physik C Particles and Fields》1986,31(1):65-69
We present results obtained in π? A (A=C, Cu, Pb) — collisions at 38 GeV/c. A single particle trigger selects events with one charged particle in the central region and large transverse momentum. The effect of this trigger on the multiplicities of all charged particles and of protons is shown. 相似文献
46.
The paper reports on properties and structure of the TiN films, which have been deposited on titanium interlayer covering a steel substrate. The Ti interlayer and the TiN film were prepared by d.c. magnetron sputtering in Ar and Ar + N2 mixture, respectively. Three Ti interlayers with different thickness h
Ti = 0.01, 0.1 and 0.2 m were prepared under the same conditions and investigated. It was found that the macroscopic residual stress in the TiN films is compressive and increases with the increasing negative bias up to approximately –150V. Also the size of the TiN crystallites decreases with the increasing negative substrate bias, varying between 250 nm and 11 nm. The critical load, which characterises the film adhesion, increases with increasing h
Ti For h
Ti 0.1 m, the critical load almost does not depend on the bias voltage. 相似文献
47.
Determination of the polyphenolic content of a Capsicum annuum L. extract by liquid chromatography coupled to photodiode array and mass spectrometry detection and evaluation of its biological activity
下载免费PDF全文
![点击此处可从《Journal of separation science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Meriem Mokhtar Jan Soukup Paola Donato Francesco Cacciola Paola Dugo Ali Riazi Pavel Jandera Luigi Mondello 《Journal of separation science》2015,38(2):171-178
The present study was aimed to investigate the polyphenolic profile of a pepper (Capsicum annuum L.) extract from Algeria and evaluate its biological activity. The total polyphenol content of the extract was determined as 1.373 mg of gallic acid equivalents (±0.0046), whereas the flavonoids were determined as 0.098 mg of quercetin (±0.0015). The determination of the complete polyphenolic profile of the extract was achieved by liquid chromatography with an RP‐amide column in combination with photodiode array and mass spectrometry detection through an electrospray ionization interface. A total of 18 compounds were identified, of which five were reported for the first time in the sample tested. Quercetin rhamnoside was the most abundant compound (82.6 μg/g of fresh pepper) followed by quercetin glucoside (19.86 μg/g). The antioxidant activity and antimicrobial effects were also determined. For the antimicrobial tests assessed against Gram‐positive and Gram‐negative bacteria, kaempferol showed the strongest inhibitory effect followed by quercetin and caffeic acids. In the study of the cytotoxicity of the extract, the cancer cells (U937) were more affected than the normal cells (peripheral blood mononucleated cells), with more than 62% inhibition at the highest concentration. 相似文献
48.
The Use of Cyclodextrin-Based LC Stationary Phases for the Separation of Chiral Dihydrobenzofuran Derivatives 总被引:1,自引:0,他引:1
The enantiomeric separation of 12 chiral dihydrobenzofurans is reported on derivatized -cyclodextrin stationary phases using high performance liquid chromatography. The hydroxypropyl -cyclodextrin chiral stationary phase (CSP) with acetonitrile/water mobile phases was the most effective combination as it baseline separated 9 of the 12 compounds. The acetyl -cyclodextrin and 2,3-dimethyl -cyclodextrin CSPs were also effective in the reverse phase mode. The native -cyclodextrin was far less effective than the non-aromatic derivatized CSPs. The aromatic functionalized CSPs showed no selectivity in the normal phase mode. Structural characteristics, such as substituent polarity and ring location, were important in the observed enantioselectivity. 相似文献
49.
In the recent decade an RF driven, low‐pressure plasma reactor with supersonic plasma jet was developed (RPJ). This reactor was successfully used for deposition of thin films of various materials. The deposition of thin films indicates that the properties of the deposited films are dependent on the sputtering or reactive sputtering processes appearing inside the nozzle (hollow athode). The nozzle (hollow athode) fabricated of different kinds of materials and alloys works both as a cathode of the radio frequency (RF) hollow cathode discharge and as a nozzle for plasma jet channel generation as well. The RF hollow cathode discharge is a secondary discharge, which is induced by the primary RF plasma generated in the reactor chamber. The present paper deals with the experimental study of this RF hollow cathode discharge. The stress is laid on the investigation of the axial distribution of discharge parameters and sputtering processes inside the nozzle. On the base of experiments, the simple model of the axial distribution of the investigated RF hollow cathode discharge has been developed. 相似文献
50.
Mallika Somayajulu-Ni?u Jagdeep K Sandhu Jerome Cohen Marianna Sikorska TS Sridhar Anca Matei Henryk Borowy-Borowski Siyaram Pandey 《BMC neuroscience》2009,10(1):88