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91.
Lucia Zetta Enrica Alberti Tiziano Motta Maurizio Canetti Fabio Bertini 《Journal of polymer science. Part A, Polymer chemistry》2007,45(20):4635-4646
Butadiene‐isoprene copolymerization with the system V(acac)3‐MAO was examined. Crystalline or amorphous copolymers were obtained depending on isoprene content. Both butadiene and isoprene units exhibit a trans‐1,4 structure and are statistically distributed along the polymer chain. Polymer microstructure, comonomer composition, and distribution along the polymer chain were determined by 13C and 1H NMR analysis. The thermal and X‐ray behaviors of the copolymers were also investigated and compared with results from solid‐state 13C NMR experiments. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4635–4646, 2007 相似文献
92.
Julia Kienberger Elisabeth Kreutzwiesner Nadja Noormofidi Ingo Klarholz Carsten Harms Christian Slugovc 《Macromolecular Symposia》2012,311(1):98-102
Summary: Anionically polymerised (poly)isoprene was functionalized with cysteamine applying thiol-ene click chemistry. Subsequent quaternisation of the primary amino groups gave polymers with antimicrobial activity against Listeria monocytogenes, Eschericchia coli, Pseudomonas fluorescens and Staphylococcus aureus as revealed from tests performed according to the Japanese Industrial Standard Z2801:2000. The novel polymers feature sufficient thermal stability for the compounding with commodity polymers such as poly(propylene) and might be used as a non leaching additive to finish commodity polymers with antimicrobial acitivity. 相似文献
93.
94.
硫化物对Pd/树脂催化剂上异戊二烯选择加氢催化性能的影响 总被引:4,自引:0,他引:4
在流体并流向上的气液固三相固定床反应器中考察了多种硫化物\r\n对负载Pd催化剂上异二戊烯加氢反应活性的影响.结果表明,在低温(\r\n60℃)和液相加氢条件下,硫化氢、二硫化碳、二甲基硫醚、二甲基二\r\n硫醚、硫醇及噻吩都能使强酸性树脂负载的Pd催化剂上异戊二烯加氢反\r\n应活性下降;随着硫化物含量的增加,异戊二烯加氢活性下降的程度增\r\n大.在硫的质量分数相同(8×10-6)的情况下,这些硫化物使催化剂\r\n失活程度的大小顺序为:二硫化碳>硫化氢>二甲基二硫醚≈乙硫醇>\r\n二甲基硫醚>噻吩.其中噻吩基本上不导致催化剂失活. 相似文献
95.
本文报道由(NdCl_3+FeCl_3)·nphen-HAl(i-Bu)_2催化体系引发异戊二烯聚合的结果。在适当Nd/Pe比下,该体系对异戊二烯聚合的活性可超过单一钕或铁催化剂的活性,同时随催化剂中钕和铁含量的不同,所得产物的微观结构变化很大,当体系中钕含量由100%→0时,产物的顺-1,4结构含量由94.4%→22.1%,而3,4结构含量由5.6%→77.9%。Al/M(N=Nd+Fe)比、单体浓度和聚合温度不仅对聚合活性有影响,对产物的微观结构影响也较大。事实表明,该聚合体系中存在着两种过渡金属(Nd和Fe)活性中心,它们按各自的机理进行异戊二烯的聚合。 相似文献
96.
Introduction Rare-earth coordination catalysts are known for their high activity and high stereospecificity in the polymerization of conjugated dienes.1-5 The copolymerization of styrene (St) with butadiene using rare earth catalyst was followed with interest soon as the rare earth coordination catalyst appeared in the early 1960s.6-14 Copolymerization of isoprene (IP) and St using coordination catalysts was reported in a few papers,10,15-18 among them only Jin et al.10 and our group18 repor… 相似文献
97.
发现了一种对异戊二烯聚合立体选择性较敏感的稀士催化体系:(β-CH_3-allyl)_2LnCl_5Mg·2T的ED(Ln)-R_3Al(Al)(Ln=Nd、Ce和La,T的ED:N,N,N′,N′-四甲基乙二胺;R=Me一,Et一,i-Bu一和Oct一).该催化体系在改变聚合温度、聚合时间、Al/Ln摩尔比、溶剂等时,可使聚异戊二烯的立体现整度有较大的改变,其中顺式-1,4、反式-1,4和3,4-链节含量的变化范围分别为19%~79%、17%~78%和0%~3.5%,还可获得较低分子量的聚合物。 相似文献
98.
99.
Yurii N. Panchenko Charles W. Bock Joseph D. Larkin Alexander V. Abramenkov Frank Kühnemann 《Structural chemistry》2008,19(3):421-428
The ab initio-based, scaled quantum-mechanical molecular force field (SQM-FF) analysis of the vibrational spectra of the s-trans and s-gauche conformers of 2-methylbuta-1,3-diene (isoprene), reported previously at the HF/6-31G//HF/6-31G computational level [Bock,
et al. J Mol Struct 160: 337, 1987], has been updated in this article using a more complete set of experimental data on the
s-gauche conformer along with revised results for the s-trans conformer obtained in the gas phase, in a low-temperature matrix, and in neat crystals. Geometrical parameters and the calculated
wavenumbers derived from the SQM-FF at the MP2(FC)/aug-cc-pVDZ//MP2(FC)/aug-cc-pVDZ level are compared to experiment. The
analyses performed are consistent with the presence of a twisted high-energy s-gauche conformer of isoprene. 相似文献
100.