全文获取类型
收费全文 | 67篇 |
免费 | 0篇 |
国内免费 | 3篇 |
专业分类
化学 | 35篇 |
晶体学 | 1篇 |
数学 | 12篇 |
物理学 | 22篇 |
出版年
2023年 | 2篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2005年 | 5篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有70条查询结果,搜索用时 0 毫秒
1.
Exploring new directions for research in problem structuring methods: on the role of cognitive style
Prior research has argued that cognitive style can have a significant impact on group decision making. In addition, several scholars have proposed that cognitive style can play a key role in the design and use of group decision support systems. However, cognitive style has not received a great deal of attention in the problem structuring methods (PSMs) community. This is surprising, given that PSMs are specifically developed to support a group in their decision making. The purpose of this paper is thus to examine the significance of cognitive style within PSMs. The paper identifies and explores the role of four different cognitive style functions in problem structuring interventions. This analysis is carried out by focusing on the different tasks embedded within a group process supported by PSMs. Implications for the research and practice of PSMs are then discussed. 相似文献
2.
Aitala EM Amato S Anjos JC Appel JA Ashery D Banerjee S Bediaga I Blaylock G Bracker SB Burchat PR Burnstein RA Carter T Carvalho HS Copty NK Cremaldi LM Darling C Denisenko K Devmal S Fernandez A Fox GF Gagnon P Gobel C Gounder K Halling AM Herrera G Hurvits G James C Kasper PA Kwan S Langs DC Leslie J Lundberg B Magnin J Massafferri A MayTal-Beck S Meadows B de Mello Neto JR Mihalcea D Milburn RH de Miranda JM Napier A Nguyen A d'Oliveira AB O'Shaughnessy K Peng KC Perera LP Purohit MV 《Physical review letters》2001,86(5):770-774
From a sample of 1172 +/- 61 D(+)-->pi(-)pi(+)pi(+) decays, we find gamma(D(+)-->pi(-)pi(+)pi(+))/gamma(D(+)-->K-pi(+)pi(+)) = 0.0311 +/- 0.0018(+0.0016)(-0.0026). Using a coherent amplitude analysis to fit the Dalitz plot of these decays, we find strong evidence that a scalar resonance of mass 478(+24)(-23) +/- 17 MeV/c(2) and width 324(+42)(-40) +/- 21 MeV/c(2) accounts for approximately half of all decays. 相似文献
3.
Toby Meadows 《Mathematical Logic Quarterly》2023,69(3):287-340
The purpose of this paper is to propose and explore a general framework within which a wide variety of model construction techniques from contemporary set theory can be subsumed. Taking our inspiration from presheaf constructions in category theory and Boolean ultrapowers, we will show that generic extensions, ultrapowers, extenders and generic ultrapowers can be construed as examples of a single model construction technique. In particular, we will show that Łoś's theorem can be construed as a specific case of Cohen's truth lemma, and we isolate the weakest conditions a filter must satisfy in order for the truth lemma to work. 相似文献
4.
B. Meadows 《中国物理 C》2010,34(6):780-787
Studies in which BABAR data have shown evidence for mixing in the neutral charm meson system are presented. A new measurement of the lifetime difference parameter ycp = (1.16±0.22±0.18)% is described. Results are also presented from a systematic study of DK and D*K invariant mass distributions from a 470 fb^-1 sample of asymmetric e^+e^- interactions recorded by the BABAR detector at the PEP-Ⅱ storage rings. A new charmed-strange meson has been observed with mass [3044 ± 8stat (-5^+30 )syst] MeV/c^2 and width [239± 35stat (-42^+46)syst]MeV/c^2. 相似文献
5.
6.
The main scope of the article is to investigate the effect of ferrite cores gap in a universal matchbox on an ultrasonic vibrating system. A gapped transformer mechanism in a universal matchbox has been thoroughly studied. Characteristics of an ultrasonic vibrating system have been recorded such as mechanical vibrations, inductance, resonant frequencies, current and voltage levels as the gap of ferrite cores gradually increases. In addition, the phase difference between the supplied voltage and the current is also computed and displayed in a Lissajous curve in order to determine the optimal gap between two ferrite cores in the universal matchbox. Explanations supplement the experiment results. 相似文献
7.
E S Meadows S L De Wall L J Barbour G W Gokel 《Journal of the American Chemical Society》2001,123(13):3092-3107
The Na(+) or K(+) cation-pi interaction has been experimentally probed by using synthetic receptors that comprise diaza-18-crown-6 lariat ethers having ethylene sidearms attached to aromatic pi-donors. The side chains are 2-(3-indolyl)ethyl (7), 2-(3-(1-methyl)indolyl)ethyl (8), 2-(3-(5-methoxy)indolyl)ethyl (9), 2-(4-hydroxyphenyl)ethyl (10), 2-phenylethyl (11), 2-pentafluorophenylethyl (12), and 2-(1-naphthyl)ethyl (13). Solid-state structures are reported for six examples of alkali metal complexes in which the cation is pi-coordinated by phenyl, phenol, or indole. Indole-containing crown, 7, adopts a similar conformation when bound by NaI, KI, KSCN, or KPF(6). In each case, the macroring and both arenes coordinate the cation; the counteranion is excluded from the solvation sphere. NMR measurements in acetone-d(6) solution confirm the observed solid-state conformations of unbound 7 and 7.NaI. In 7.Na(+) and 7.K(+), the pyrrolo, rather than benzo, subunit of indole is the pi-donor for the alkali metal cation. Cation-pi complexes were also observed for 10.KI and11.KI. In these cases, the orientation of the cation on the aromatic ring is in accord with the binding site predicted by computational studies. In contrast to the phenyl case (11) the pentafluorophenyl group of 12 failed to coordinate K(+). Solid-state structures are also reported for 7.NaPF(6), 10.NaI, 11.NaI, 13.KI, 13.KPF(6), and 9.NaI, in which cation-pi complexation is not observed. Steric and electrostatic considerations in the pi-complexation of alkali metal cations by these lariat ethers are thought to account for the observed complexation behavior or lack thereof. 相似文献
8.
A survey of strategic planning managers was considered to identify the current practice of developing corporate visions, with a particular focus on how the vision was developed. The paper begins with a brief review of the literature concerning organisational visions and their development. The issues addressed by the survey and the research methodology are then described, and the results of the research presented. The paper ends with a discussion of the findings of the survey, and suggests ways of progressing research in this area. 相似文献
9.
F R Johnston J E Boyland M Meadows E Shale 《The Journal of the Operational Research Society》1999,50(12):1267-1271
Simple (equally weighted) moving averages are frequently used to estimate the current level of a time series, with this value being projected as a forecast for future observations. A key measure of the effectiveness of the method is the sampling error of the estimator, which this paper defines in terms of characteristics of the data. This enables the optimal length of the average for any steady state model to be established and the lead time forecast error derived. A comparison of the performance of a simple moving average (SMA) with an exponentially weighted moving average (EWMA) is made. It is shown that, for a steady state model, the variance of the forecast error is typically less than 3% higher than the appropriate EWMA. This relatively small difference may explain the inconclusive results from the empirical studies about the relative predictive performance of the two methods. 相似文献
10.
Chameleon sequences are amino acid sequences found in several distinct configurations in experiment. They challenge our understanding of the link between sequence and structure, and provide insight into structural competition in proteins. Here, we study the energy landscapes for three such sequences, and interrogate how pulling and twisting forces impact the available structural ensembles. Chameleon sequences do not necessarily exhibit multiple structural ensembles on a multifunnel energy landscape when we consider them in isolation. The application of even small forces leads to drastic changes in the energy landscapes. For pulling forces, we observe transitions from helical to extended structures in a very small span of forces. For twisting forces, the picture is much more complex, and highly dependent on the magnitude and handedness of the applied force as well as the reference angle for the twist. Depending on these parameters, more complex and more simplistic energy landscapes are observed alongside more and less diverse structural ensembles. The impact of even small forces is significant, confirming their likely role in folding events. In addition, small forces exerted by the remaining scaffold of a protein may be sufficient to lead to the adoption of a specific structural ensemble by a chameleon sequence. 相似文献