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351.
运用FTIR原位跟踪方法, 以巯基和碳碳双键官能团转化率做为检测指标, 研究了巯基化合物的结构对紫外光固化巯基/乙烯基共聚体系固化行为的影响. 在相同的反应条件下, 苯硫酚的反应活性明显低于硫醇的反应活性; 巯基化合物中吸电子基团(酯基)会使反应活性降低, 而推电子基团(异丙撑基)会使反应活性提高. 采用量子化学中密度函数理论B3LYP/6-31G*的方法和基组对巯基化合物中S与H的净电荷和键长计算结果表明:吸电子基团使S上的净电荷减少, 其与H的共价键键长缩短; 而推电子基团的作用则相反. 此结果佐证了FTIR的实验结果, 揭示了巯基化合物结构对巯基/乙烯基共聚体系紫外光固化反应活性的影响机理. 相似文献
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Brian J. Adzima Christopher J. Kloxin Cole A. DeForest Kristi S. Anseth Christopher N. Bowman 《Macromolecular rapid communications》2012,33(24):2092-2096
3D structures are written and developed in a crosslinked polymer initially formed by a Diels–Alder reaction. Unlike conventional liquid resists, small features cannot sediment, as the reversible crosslinks function as a support, and the modulus of the material is in the MPa range at room temperature. The support structure, however, can be easily removed by heating the material, and depolymerizing the polymer into a mixture of low‐viscosity monomers. Complex shapes are written into the polymer network using two‐photon techniques to spatially control the photoinitiation and subsequent thiol–ene reaction to selectively convert the Diels–Alder adducts into irreversible crosslinks. 相似文献
355.
Lionel Petton Andrs E. Ciolino Milan M. Stamenovi Pieter Espeel Filip E. Du Prez 《Macromolecular rapid communications》2012,33(15):1310-1315
A straightforward, novel strategy based on the in situ functionalization of polymers prepared by nitroxide‐mediated polymerization (NMP), for the use as an extension toward block copolymers and post‐polymerization modifications, has been investigated. The nitroxide end group is exchanged for a thiocarbonylthio end group by a rapid transfer reaction with bis(thiobenzoyl) disulfide to generate in situ reversible addition–fragmentation chain transfer (RAFT) macroinitiators. Moreover, not only have these macroinitiators been used in chain extension and block copolymerization experiments by the RAFT process but also a thiol‐terminated polymer is synthesized by aminolysis of the RAFT end group and subsequently reacted with dodecyl vinyl ether by thiol‐ene chemistry. 相似文献
356.
The photochromic 1,3‐diazabiclyclo[3.1.0]hex‐3‐enes 5 and 6 were synthesized from two premade tris‐aldehydes and two premade aziridinyl ketones and characterized (Scheme 1). Their spectra showed structure? photochromic behavior relationships (SPBR), which were analyzed. 相似文献
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《Mendeleev Communications》2023,33(1):9-10
Diels–Alder adducts of levoglucosenone with isoprene, butadiene and piperylene in the presence of AlCl3 smoothly react with acetaldehyde or benzaldehyde to give products of the ene reaction, the hydroxy group of the primary intermediates participating in the formation of semiketal moiety. The yields of the reaction products depend both on the Lewis acid used (AlCl , BF ·Et O, ZnBr , SnCl or EtAlCl2) and on the nature of the substrate. 相似文献