全文获取类型
收费全文 | 146篇 |
免费 | 0篇 |
专业分类
化学 | 90篇 |
力学 | 5篇 |
数学 | 6篇 |
物理学 | 45篇 |
出版年
2021年 | 2篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 27篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 9篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1995年 | 2篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有146条查询结果,搜索用时 31 毫秒
11.
Sessler JL Maeda H Mizuno T Lynch VM Furuta H 《Chemical communications (Cambridge, England)》2002,(8):862-863
Novel quinoxaline derivatives bearing dipyrromethane or tripyrromethane substituents act as improved anion receptors as compared to the unsubstituted dipyrrolylquinoxaline core from which they are derived. 相似文献
12.
Jun-Ichi Asakura Masakuni Yoshihara Takaaki Shindo Yoshio Matsubara Toshihisa Maeshima 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):371-377
The radical copolymerization of vinylidene chloride (Vc, M1) with 3(2-methyl)-6-methylpyridazinone (I, M2) was carried out in benzene, ethanol, phenol, and acetic acid at 60 and 80°C. The monomer reactivity ratios were found to vary with the reaction conditions. The linear correlationships were obtained by plotting the values of log r1 against those of V C[dbnd]O and V C[dbnd]C of monomers determined in the solvents. 相似文献
13.
Jun-Ichi Asakura Masakuni Yoshihara Yoshio Matsubara Toshihisa Maeshima 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):1473-1478
Radical copolymerization of styrene (St, M1) with acrylonitrile (AN, M2) has been carried out using azobisisobutylonitrile as an initiator in benzene, dimethylsulfoxide, acetonitrile, and ethanol at 60 and 80°C. Good linear correlationships were obtained by plotting the values of log r1, log r2, Q2, and e2 against those of vC[dbnd]N and vC[dbnd]C determined in the solvents: the increase in the interaction between AN and the solvent was found to decrease the values of log r1 and e2 but to increase those of log r2 and Q2. The results are discussed in terms of the solvation both in the ground state and in the transition state. 相似文献
14.
Polymerization of acrolein(AL) in the presence of imidazole(Im) has been investigated in tetrahydrofuran or methanol below room temperature. The polymers obtained, white or pale yellow powders, were found to be composed of vinyl polymer with one Im group attached and having an aldehyde side chain, of which 70–80 mole % of the aldehyde revealed bridge structure. The number-average molecular weight (M n) of these polymers was determined to be in the range of 317 to 691. The rate of polmerization Rp was expressed by the equation, R + k[Im] [AL]2. The addition of water or dimethyl sulfoxide accelerated the polymerization reaction, while the presence of benzaldehyde or N,N'-dimethylformamide decreased Rp. The structure of addition products in the initial polymerization step was confirmed by IR and NMR spectra, and the observations of polymerization system was carried out by UV and NMR spectra. The polymerization mechanisms were discussed on the basis of these results. 相似文献
15.
Eiichi Ozu Natsuki Yamashita Toshihisa Maeshima Ion C. Baianu Lun-Shin Wei 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1637-1653
N-(Butyl-3-one)imidazole acts as an initiating adduct which is formed in the anionic polymerization of methyl vinyl ketone (MVK) induced by imidazole (Im) and is directly formed from Im and the MVK monomer. The kinetics of the anionic homopolymerization of MVK and acrylamide (AAm) under argon in the presence of the adduct were investigated in tetrahydrofuran (THF). The rate of polymerization for the MVK system is expressed as Rp = k[Adduct] [MVK], where k = 3.1 × 10?6 L/(mol·s)in THF at 30°C. The overall activation energy, Ea , was found to be 5.34 kcal/mol. The Rp for the AAm system is expressed as Rp = k[Adduct] [AAm], where k = 6.8 × 10?6 L/(mol·s) in THF at 30°C, with Ea 7.78 kcal/mol. The mechanism of the polymerization induced by the initiator adduct is discussed on the basis of these results. 相似文献
16.
Natsuki Yamashita Atsuhito Tadokoro Eiichiozu Toshihisa Maeshima Ion C. Baianu Lun-Shin Wei 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1223-1239
The anionic polymerization of acrolein (AL) with N, N-dimethylamino-propylacrylamide (DMAPA) in the presence of water was investigated in tetrahydrofuran, benzene, and ethanol at 0°C in a nitrogen atmosphere. The resulting polymers were found to be essentially vinyl polymers with one DMAPA attached and an aldehyde side chain. From observations of the polymerization process by 1H NMR, we find that polymerization was initiated by the hydroxyl anion formed in the thermodynamic equilibrium between the amine of DMAPA and water. The hydrogen transfer reaction of DMAPA was caused by the propagating poly-AL anion. On the other hand, the monomer reactivity ratios and the Q2-e2values of DMAPA were determined by the free-radical copolymerization of styrene (St, M1) with DMAPA and AIBN as initiator. 相似文献
17.
18.
Takuya Tomidokoro Takeshi Yokomori Toshihisa Ueda Hong G. Im 《Proceedings of the Combustion Institute》2021,38(2):2543-2550
Propagation of a H2-added strained laminar CH4/air flame in a rich-to-lean stratified mixture is numerically studied. The back-support effect, which is known to enhance the consumption speed of a flame propagating into a leaner mixture compared to that into a homogeneous mixture, is evaluated. A new method is devised to characterize unsteady reactant-to-reactant counterflow flames under transiently decreasing equivalence ratio, in order to elucidate the influence of flow strain on the back-support effect. In contrast to the conventional reactant-to-product configurations, the current configuration is more relevant to unsteady stratified flames back-supported by their own combustion products. Moreover, since H2 distribution downstream of the flame is known to play a crucial role in back-supported CH4/air flames, the influence of H2 addition in the upstream mixture is examined. The results suggest that a larger strain rate leads to a larger equivalence ratio gradient at the reaction zone through increased flow divergence, which amplifies the back-support. Meanwhile, since H2 addition in the upstream mixture does not affect the downstream H2 content, the relative increase in the consumption speed, i.e. the back-support, is suppressed with larger H2 addition. Especially, when the upstream H2 content decreases with the equivalence ratio, the H2 preferentially diffuses toward the unburned gas, which mitigates H2 accumulation in the preheat zone and further weakens the back-support. 相似文献
19.
Perylene bisimide (PBI) is a fluorescent dye which has strong emission and high photostability. Although PBI has been widely used for industrial materials, the application of PBI in analytical fields was limited mainly due to its high hydrophobicity. In recent years, however, unique and useful analytical methods based on PBI platform are being successfully developed by utilizing the characteristic features of this compound including its high hydrophobicity. In this article, the recent trend of environmental and biological analysis using PBI is reviewed. 相似文献
20.
Schukraft J. Maeshima K. Wenzel H. Haidt D. Foa L. Ali A. 《The European Physical Journal C - Particles and Fields》2004,33(1):s1-s4
The European Physical Journal C - The fourth LHC Symposium was held at Fermilab in May 2003 following the first two meetings in Russia and the third symposium in Italy. The theme of this meeting... 相似文献