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81.
E. Winterfeldt 《Angewandte Chemie (International ed. in English)》1967,6(5):423-434
The possibilities of additions to the activated CC triple bond are discussed with the aid of a number of examples. The additions of donors that contain no active hydrogen are generally initiated via a dipolar primary complex, which can undergo stabilization by rearrangement, cyclization, or addition reactions. Preparative aspects of these reactions are also discussed. They offer routes for the preparation of heterocycles, particularly pyrrole and thiophene derivatives. 相似文献
82.
Based on the conjugated polarization theory,it is expressed as the conjugated polarizability potential (CPP)that the discrepancy between the average electrostatic energy of dipolar state and the electrostatic energy of non-polar state in the conjugated polarizability procedure for the conjugated alkenes. The correlation between CPP and the energy of ultraviolet absorption maximum,and the correlation between the energy of frontier molecular orbital obtained by ab initio calculation of quantum chemistry and the energy of ultraviolet absorption maximum have been carried out for the conjugated alkenes. Both correlation equations show a similar estimated precision. Further, the contribution of alkyl polarizability effect to the stability of dipolar state for the alkyl substituted alkenes with the effective polarizability effect index(PEI(ef))was quantified. Relating the above two parameters CPP and PEI(ef)to the energy of ultraviolet absorption maximum of the substituted alkenes in a two-parameter expression with a good prediction ability was obtained:v=1.1746+5.0187CPP-0.43204PEI (ef),R=0.9995,s=0.0403,F=10853.28,n=23. The investigated results also indicate that it is less effective to reduce the energy of ultraviolet absorption maximum by means of increasing the alkyl substituent groups than lengthening the conjugated backbone chain in the conjugated alkenes. 相似文献
83.
Teng-fei Niu Jing Cheng Chang-li Zhuo Ding-yun Jiang Xing-ge Shu Bang-qing Ni 《Tetrahedron letters》2017,58(37):3667-3671
A mild, practical and efficient strategy to prepare β-keto sulfones has been developed by visible light promoted reactions. This reaction involves Ir(ppy)2(dtbbpy)PF6 catalyzed direct funcationalization of alkenes with sulfonyl chlorides under mild conditions. Air was used as oxidant without any additives. The transformation affords the corresponding products in moderate to high yields. 相似文献
84.
85.
Aleti R. Reddy Payare L. Sangwan Praveen K. Chinthakindi Saleem Farooq Vidavalur Siddaiah Surrinder Koul 《Helvetica chimica acta》2013,96(7):1313-1324
A rapid, convenient, and efficient method has been achieved for regioselective iodoesterification of alkenes with aliphatic and aromatic acids, and protected amino acids in the presence of N‐iodosuccinimide (NIS) in nearly quantitative yields. Optically enriched iodohydrins have been achieved by LiAlH4 (LAH) reduction of diastereoisomeric iodo esters. 相似文献
86.
Double silylation of 1,3-butadienes with chlorosilanes was found to proceed by using titanocene dichloride as the catalyst in the presence of nBuMgCl, giving rise to 1,4-disilylated 2-butenes in good yields. Aryl substituted alkenes also afforded 1,2-disilylated products under similar conditions. 相似文献
87.
Oximes are converted to the parent carbonyl compounds in good yields when treated with 1,3‐dichloro‐5,5‐dimethylhydantoin (DCDMH) ( 1 ). An optimized procedure has been developed; the simple work‐up minimizes loss of product and oximes have been selectively oxidized in the presence of alcohols and alkenes. 相似文献
88.
Tandem palladium-catalyzed cross-coupling of alkyl, alkenyl, alkynyl, aryl, and heteroaryl 2-substituted 1,1-dibromo-1-alkenes with aryl or heteroaryl boronic acids or borate esters and dehydrobromination of the intermediate coupled products afforded internal alkynes in moderate to good yields (up to 89%). The synthesis has been carried out in a one-pot process and in a two-step sequence according to the nature of the starting 1,1-dibromoalkenes. The reported protocol is compatible with the presence in the 1,1-dibromo-1-alkene molecule of additional reactive halogen–carbon bonds, thus allowing to build up more complex alkyne derivatives. 相似文献
89.
A protocol for the synthesis of stereodefined 1-aryl(heteroaryl) substituted 1,2-bis(2-bromopyridin-3-yl)ethenes by tandem Suzuki-Miyaura cross-coupling reactions and an example of convention into 5-phenyl-1,10-phenanthroline are described. 相似文献
90.
Dao-Ming Wang Li-Qin She Hao Yuan Dr. Yichen Wu Prof. Dr. Yong Tang Prof. Dr. Peng Wang 《Angewandte Chemie (International ed. in English)》2023,62(35):e202304573
The use of molecular oxygen as the terminal oxidant in transition metal catalyzed oxidative process is an appealing and challenging task in organic synthetic chemistry. Here, we report a Ni-catalyzed hydroxylarylation of unactivated alkenes enabled by a β-diketone ligand with high efficiency and excellent regioselectivity employing molecular oxygen as the oxidant and hydroxyl source. This reaction features mild conditions, broad substrate scope and incredible heterocycle compatibility, providing a variety of β-hydroxylamides, γ-hydroxylamides, β-aminoalcohols, γ-aminoalcohols, and 1,3-diols in high yields. The synthetic value of this methodology was demonstrated by the efficient synthesis of two bioactive compounds, (±)-3′-methoxyl citreochlorol and tea catechin metabolites M4. 相似文献