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21.
A series of 4-halophosphaisocoumarins were prepared with high regioselectivity in good to excellent yields under mild conditions by the reaction of 2-(1-alkynyl)phenylphosphonic acid diesters with I2 in CHCl3 or ICl in CH2Cl2, or by the reaction of 2-(1-alkynyl)phenylphosphonic acid monoesters with NBS or NCS in DMF. Whether the alkynylphosphonates could cyclize or not was affected by the substituents, reaction solvents and electrophiles. A rationale for this reaction is discussed. 相似文献
22.
Rongti Li 《Tetrahedron letters》2005,46(31):5117-5120
Coupling of alkynylbenzoyl systems with γ,δ-unsaturated Fischer carbene complexes leads to the formation of hydrophenanthrene derivatives. This reaction is not affected by aqueous systems, which offer a further advantage such that chromium hexacarbonyl sublimes during the reaction process. Chromium carbene-alkyne coupling processes can thus be performed in environmentally friendly solvents with substoichiometric net consumption of chromium hexacarbonyl. 相似文献
23.
Xiaoxia Zhang 《Tetrahedron》2010,66(6):1177-5455
A wide variety of substituted quinolines are readily synthesized under mild reaction conditions by the 6-endo-dig electrophilic cyclization of N-(2-alkynyl)anilines by ICl, I2, Br2, PhSeBr, and p-O2NC6H4SCl. The reaction affords 3-halogen-, selenium- and sulfur-containing quinolines in moderate to good yields in the presence of various functional groups. Analogous quinolines bearing a hydrogen in the 3-position have been synthesized by the Hg(OTf)2-catalyzed ring closure of these same alkynylanilines. 相似文献
24.
K. Rajender Reddy M. Venkateshwar C. Uma Maheswari P. Santhosh Kumar 《Tetrahedron letters》2010,51(16):2170-1420
An efficient synthesis of 1-iodoalkynes and iodophenols was easily achieved by employing simple KI and TBHP. The reaction does not involve the use of a metal and base combination. A variety of substituted alkynes and phenols were prepared with good to excellent yield. 相似文献
25.
Alexander Himmelspach 《Journal of organometallic chemistry》2010,695(9):1337-2631
Cesium and tetraethylammonium salts of the ethynyl functionalized monocarba-closo-dodecaborate anions [12-HCC-closo-1-CB11H11]− and [7,12-(HCC)2-closo-1-CB11H10]− were obtained by desilylation of [Et4N][12-Me3SiCC-closo-1-CB11H11] and [Et4N][7,12-(Me3SiCC)2-closo-1-CB11H10], respectively. Their thermal properties were examined by differential scanning calorimetry. The compounds were characterized by multi-NMR, IR, and Raman spectroscopy, (−)-MALDI mass spectrometry, and elemental analysis. Single-crystals of Cs[12-HCC-closo-1-CB11H11] and [Et4N][7,12-(HCC)2-closo-1-CB11H10] were studied by X-ray diffraction. The discussion of the spectroscopic and structural properties is supported by data derived from theoretical calculations using density functional theory as well as perturbation theory. 相似文献
26.
Hanane Bafqiren 《Tetrahedron》2010,66(34):7028-7034
Water mediates synthesis of novel hindered Schiff bases via transmination protocol. The feature of the procedure is that it allows both tuning of steric and electronic factors of the substituents and mono-imination of vicinal diamines, which potentially facilitates one-pot approach to unsymmetrical metal ligands. 相似文献
27.
An unsymmetrical organic compound with carbazole (Cz) as donor and benzothiadiazole (BTD) as acceptor (D-π-A-π∗-D∗) was designed and synthesized via simple Heck reaction. The unique crystal structure of Cz-BTD-Cz∗ shows a ladder-like packing mode. A two molecule pair stacks parallelly with each other in each packing unit. In each cell, one Cz moiety is connected with BTD by vinylene bond in same plane. However, the other Cz group is connected to BTD by a one-end vinyl bond in almost perpendicular position to the coplanar part of the molecule. The shortest intermolecular plane distance is 3.48 ± 0.1 Å. The photophysical properties of Cz-BTD-Cz∗ in solution and in bulky crystalline powder state were studied. In bulk crystalline powder state, it has a red-shifted emission band peaked at 609 nm relative to that in solution, and the FWHM was reduced to only 58 nm. Electrochemical properties were also investigated. 相似文献
28.
A protocol for the one-pot synthesis of internal alkynes from 1,1-dibromoalkenes is reported. The method is hinged upon the Suzuki-Miyaura cross-coupling of 2-aryl- or 2-heteroaryl-1,1-dibromoalkenes with aryl or heteroaryl boronic acids or borate esters followed by dehydrobromination of the intermediate coupled products. Yields up to 89% were obtained. 相似文献
29.
研究了Ni/Fe催化剂对废水中偏二甲肼臭氧化分解的催化作用,考察了组分含量、体系的pH值和偏二甲肼初始浓度对催化反应的影响.结果表明,Ni/Fe催化剂对水中偏二甲肼的臭氧化具有良好的催化活性.催化剂组分含量、体系的pH值和初始浓度对反应的影响程度不大.对催化剂的XRD表征结果表明,催化剂主要由尖晶石结构的铁酸盐和FeNi3合金相组成,催化剂的良好催化性能与催化剂中尖晶石结构的铁酸盐和FeNi3合金相的形成有关. 相似文献
30.
Three silylated γ-alkynylfurans were prepared and subjected to both gold and platinum catalysts. The TMS- and the TBDMS-substituted furans reacted. With AuCl3 and the binuclear [(Ph3PAu)2Cl][BF4] catalyst a hydroarylation of the alkyne was observed. Na[AuCl4] gave phenols as the product, but these were formed only after in situ desilylation of the starting material by the gold catalyst and thus the wrong isomer dominated. Only with PtCl2(MeCN)2 phenols with a silyl group were formed. The TBDPS-substituted furan failed to react. Two alkynylsilanes were synthesized, but they also failed to react. 相似文献