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排序方式: 共有4043条查询结果,搜索用时 15 毫秒
1.
Hong Song Ya Li Qi-Jun Yao Liang Jin Lei Liu Yan-Hua Liu Prof. Dr. Bing-Feng Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(16):6638-6642
The atroposelective synthesis of axially chiral styrenes remains a formidable challenge due to their relatively lower rotational barriers compared to the biaryl atropoisomers. Herein, we describe the construction of axially chiral styrenes through PdII-catalyzed atroposelective C−H olefination, using a bulky amino amide as a transient chiral auxiliary. Various axially chiral styrenes were produced with good yields and high enantioselectivity (up to 95 % yield and 99 % ee). Carboxylic acid derivatives of the resulting axially chiral styrenes showed superior enantiocontrol over the biaryl counterparts in CoIII-catalyzed enantioselective C(sp3)−H amidation of thioamide. Mechanistic studies suggest that C−H cleavage is the enantioselectivity-determining step. 相似文献
2.
Yang Wang Vladimir Gevorgyan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(7):2283-2287
A silanol‐directed, palladium‐catalyzed C H carboxylation reaction of phenols to give salicylic acids has been developed. This method features high efficiency and selectivity, and excellent functional‐group tolerance. The generality of this method was demonstrated by the carboxylation of estrone and by the synthesis of an unsymmetrically o,o′‐disubstituted phenolic compound through two sequential C H functionalization processes. 相似文献
3.
Lei Wang Kenan Zhang Yuzhuo Wang Wenbo Li Mingjie Chen Prof. Dr. Junliang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(11):4451-4457
Reported here is a highly efficient Pd/Xiang-Phos catalyzed enantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines in good yields with up to 97 % ee. The sterically bulky and electron-rich (S,Rs)- NMe-X2 ligand is responsible for the excellent reactivities and enantioselectivities. The salient features of this transformation include mild reaction conditions, general substrate scope, good functional-group tolerance, good yields, high enantioselectivities, easy scale-up, and application in the late-stage modification of bioactive compounds. The obtained products can be readily transformed into useful chiral 1,3-aminoalcohols. 相似文献
4.
Wenjun Yang Bo Ling Bowen Hu Haolin Yin Prof. Dr. Jianyou Mao Prof. Dr. Patrick J. Walsh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(1):167-172
An umpolung 1,4-addition of aryl iodides to enals promoted by cooperative (terpy)Pd/NHC catalysis was developed that generates various bioactive β,β-diaryl propanoate derivatives. This system is not only the first reported palladium-catalyzed arylation of NHC-bound homoenolates but also expands the scope of NHC-induced umpolung transformations. A diverse array of functional groups such as esters, nitriles, alcohols, and heterocycles are tolerated under the mild conditions. This method also circumvents the use of moisture-sensitive organometallic reagents. 相似文献
5.
6.
《Tetrahedron letters》2019,60(30):2035-2037
We report on an approach to truncate the tricyclic 5H-chromeno[2,3-b]pyridin-5-one core of amlexanox, an approved drug under investigation for the treatment of obesity, to the bicyclic 4H-pyrano[2,3-b]pyridin-4-one (8-azachromone) core. A short, concise synthesis generates a key intermediate with requisite functionality on the pyridyl A-ring and iodo functionality on the 4-pyrone B-ring upon which palladium-catalyzed cross-coupling and subsequent reactions generate representative analogues. One of these shows a 14.2-fold increase in aqueous solubility over amlexanox. 相似文献
7.
Palladium catalyzed domino C-H functionalization reaction of arylaldehyde with dihaloarene has been developed to access 9-flourenone molecules. Bidentate ligand assisted strategy, single step reaction, high yield and excellent functional group tolerance make this method concise and effective for the synthesis of 9-flourenone. In addition, proposed method has been successfully employed to synthesise Tilorone in gram scale. 相似文献
8.
A microwave-assisted base-free intramolecular cross dehydrogenative coupling (CDC) of 3-aniline substituted coumarins and quinolinones have been developed. A broad range of indolo[2,3-c]coumarins and indolo[2,3-c]quinolinones can be easily afforded in good to high yields (up to 93%) under palladium catalysis. The method is among the most straightforward and convenient ways to access these fused polyheterocycles. 相似文献
9.
10.
Lujia Zhou Sanliang Li Dr. Bing Xu Danting Ji Lizuo Wu Prof. Dr. Yu Liu Zhan-Ming Zhang Prof. Dr. Junliang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(7):2791-2797
Sonogashira-type cross-couplings are one of the most significant alkynylations in organic chemistry. One of the first palladium-catalyzed intramolecular Heck/Sonogashira reactions of alkenes with terminal alkynes is now reported. With this method, a variety of uniquely substituted chiral benzene-fused heterocycles bearing a propargyl-substituted all-carbon quaternary stereocenter were obtained in a straightforward, high-yielding, and highly stereoselective manner under mild conditions. Salient features of this process include the use of readily available substrates, high selectivities, a broad substrate scope as well as versatile product functionalizations. 相似文献