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851.
An alternative synthetic route to 1,4,5-trisubstituted imidazoles from α-imino ketone, which can be prepared from imidoyl chlorides and aromatic aldehydes via N-heterocycle carbene-catalyzed aroylation was developed. This methodology consists of simple transformations, allowing a rapid access to imidazole derivatives with various aryl substituents at the desired positions. 相似文献
852.
Fluctuating Carbonaceous Networks with a Persistent Molecular Shape: A Saddle‐Shaped Geodesic Framework of 1,3,5‐Trisubstituted Benzene (Phenine) 下载免费PDF全文
Dr. Koki Ikemoto Jennie Lin Ryo Kobayashi Dr. Sota Sato Prof. Dr. Hiroyuki Isobe 《Angewandte Chemie (International ed. in English)》2018,57(28):8555-8559
A saddle‐shaped macromolecule has been synthesized. The molecule was designed as a geodesic saddle with 1,3,5‐trisubstituted benzene (named phenine) as the fundamental unit. The phenines were woven into a polygonal framework that was composed of 168 sp2‐hybridized carbon atoms. The saddle‐shaped structure with unique symmetry showed atypical conformational changes. The biaryl linkages in this molecule had a small energy barrier for rotation, and these structural fluctuations resulted in seven 1H NMR resonances representing 84 aromatic hydrogen atoms. Nevertheless, the overall saddle shape of the molecule was persistent, and the “up” and “down” orientations of phenine moieties circulated to give average 1H resonances. The structural characteristics of this molecule, including the anomalous entropy‐driven dimerization, may deepen our understanding of defect‐rich graphitic sheets. 相似文献
853.
Metal‐ and Oxidant‐Free Alkenyl C−H/Aromatic C−H Cross‐Coupling Using Electrochemically Generated Iodosulfonium Ions 下载免费PDF全文
Dr. Ryutaro Hayashi Dr. Akihiro Shimizu Jonathan A. Davies Yu Ishizaki Prof. Dr. Chris Willis Prof. Dr. Jun‐ichi Yoshida 《Angewandte Chemie (International ed. in English)》2018,57(39):12891-12895
A three‐step transformation consisting of 1) addition of electrochemically generated iodosulfonium ions to vinylarenes to give (1‐aryl‐2‐iodoethoxy)sulfonium ions, 2) nucleophilic substitution by subsequently added aromatic compounds to give 1,1‐diaryl‐2‐iodoethane, and 3) elimination of HI with a base to give 1,1‐diarylethenes was developed. The transformation serves as a powerful metal‐ and chemical‐oxidant‐free method for alkenyl C?H/aromatic C?H cross‐coupling. 相似文献
854.
Inside Back Cover: Giant Hysteretic Single‐Molecule Electric Polarisation Switching above Room Temperature (Angew. Chem. Int. Ed. 41/2018) 下载免费PDF全文
855.
Dr. Masahito Yoshida Dr. Koya Saito Dr. Hikaru Kato Prof. Dr. Sachiko Tsukamoto Prof. Dr. Takayuki Doi 《Angewandte Chemie (International ed. in English)》2018,57(18):5147-5150
The total synthesis of siladenoserinol A, an inhibitor of the p53–Hdm2 interaction, has been achieved. AuCl3‐catalyzed hydroalkoxylation of an alkynoate derivative smoothly and regioselectively proceeded to afford a bicycloketal in excellent yield. A glycerophosphocholine moiety was successfully introduced through the Horner–Wadsworth–Emmons reaction using an originally developed phosphonoacetate derivative. Finally, removal of the acid‐labile protecting groups, followed by regioselective sulfamate formation of the serinol moiety afforded the desired siladenoserinol A, and benzoyl and desulfamated analogues were also successfully synthesized. Biological evaluation showed that the sulfamate is essential for biological activity, and modification of the acyl group on the bicycloketal can improve the inhibitory activity against the p53–Hdm2 interaction. 相似文献
856.
Cover Picture: Catalyst‐Enabled Site‐Divergent Stereoselective Michael Reactions: Overriding Intrinsic Reactivity of Enynyl Carbonyl Acceptors (Angew. Chem. Int. Ed. 17/2018) 下载免费PDF全文
857.
Matsuta K. Minamisono T. Tanigaki M. Fukuda M. Nojiri Y. Mihara M. Onishi T. Yamaguchi T. Harada A. Sasaki M. Miyake T. Minamisono K. Fukao T. Sato K. Matsumoto Y. Ohtsubo T. Fukuda S. Momota S. Yoshida K. Ozawa A. Kobayashi T. Tanihata I. Alonso J. R. Krebs G. F. Symons T. J. M. 《Hyperfine Interactions》1996,97(1):519-526
The magnetic moments of the proton drip-line nuclei13O(I
= 3/2–,T
1/2 = 8.6 ms) and 9C(I
= 3/2–,T
1/2 = 126 ms) have been determined for the first time through the combined techniques of polarized radioactive nuclear beams and-NMR detection. The observed magnetic moments are ¦(13O)¦ = 1.3891 ±0.0003
N and ¦(9C)¦ = 1.3914 ±0.0005
N. Spin expectation values are deduced to be 0.76 and 1.44 for13O and9C, respectively. While the of13O is consistent with the systematics from isospinT= 1/2 mirror pairs, the of9C is unusually large, even far larger than the single particle value, = 1. 相似文献
858.
859.
Mau CM Nakao Y Yoshida WY Scheuer PJ Kelly-Borges M 《The Journal of organic chemistry》1996,61(18):6302-6304
From the sponge, Ircinia dendroides, collected in Indonesia we isolated a new cyclic hexapeptide, waiakeamide (1). Its structure, consisting of three proline residues, two methionine sulfoxides, and one thiazolylphenylalanine, was elucidated by spectral analysis and chemical degradation. Isolation and structural elucidation of waiakeamide is described. 相似文献
860.