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41.
Revised structure of terchebin is shown by II-B. Granatin B, a new ellagitannin, has structure V in which partial structure Ic?Id is enantiomeric to Ia?Ib in II-B and geraniin. 相似文献
42.
The MCD spectra of phloroglucin, 1,3,5-trimethoxybenzene, 1,3,5-tricyanobenzene, 1,3,5-trinitrobenzene, 1,3,5-benzenetricarboxylic acid and 1,3,5-benzenetricarbonyl chloride were measured. For the 1E′ ← 1A′1 transition of phloroglucin or 1,3,5-tricyanobenzene and the 1E′ ← 1A′ transition of 1,3,5-trimethoxybenzene, the Faraday A term was observed and the A/D value was extracted. However, 1,3,5-trinitrobenzene, 1,3,5-benzenetricarboxylic acid and 1,3,5-benzenetricarbonyl chloride showed no magnetic circular dichroism in this spectral region. The magnetic moments in the 1E′ states of these molecules seem to be quenched by the effects of substituents. The magnetic moments in the 1E′ states of benzene derivatives are sensitive to substitution in the benzene ring. 相似文献
43.
Ohne Zusammenfassung 相似文献
44.
45.
A. K. Kurilkin T. Saito V. P. Ladygin T. Uesaka T. A. Vasiliev M. Janek M. Hatano A. Yu. Isupov H. Kato N. B. Ladygina Y. Maeda A. I. Malakhov J. Nishikawa T. Ohnishi H. Okamura S. G. Reznikov H. Sakai N. Sakamoto S. Sakoda Y. Satou K. Sekiguchi K. Suda A. Tamii N. Uchigashima K. Yako 《The European physical journal. Special topics》2008,162(1):133-136
The data on the vector A
y
and tensor A
yy
, A
xx
, A
xz
analyzing powers for the
d → 3H p reaction have been obtained at the energy of the initial deuteron of 200MeV in the angular range of 0–95 degrees in the c.m.s.
The calculations performed within one-nucleon exchange model with the use of the standard three-nucleon bound state wave functions
fail to reproduce the data on the tensor analyzing powers. 相似文献
46.
Naomichi Hatano 《Molecular physics》2019,117(15-16):2121-2127
The Lindblad equation for a two-level system under an electric field is analyzed by mapping to a linear equation with a non-Hermitian matrix. Exceptional points of the matrix are found to be extensive; the second-order ones are located on lines in a two-dimensional parameter space, while the third-order one is at a point. 相似文献
47.
Inside Cover: A Puckered Singlet Cyclopentane‐1,3‐diyl: Detection of the Third Isomer in Homolysis (Chem. Eur. J. 7/2016)
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48.
A highly enantioselective organozinc (R2Zn) addition to a series of aldehydes and ketones was developed based on conjugate Lewis acid–Lewis base catalysis. Optically active secondary and tertiary alcohols were obtained in high yields with high enantioselectivities without Ti(IV) compounds. Bifunctional chiral 3,3′‐diphosphoryl‐BINOL ligands were designed and prepared through a phospho‐Fries rearrangement as a key step. On the other hand, bifunctional chiral phosphoramide ligands were designed and prepared from L ‐valine. Mechanistic studies were performed by X‐ray analyses of Zn(II) cluster and chiral ligands, a 31P NMR experiment on Zn(II) complexes, and stoichiometric reactions with some chiral or achiral Zn(II) complexes to propose a transition state assembly that includes monomeric active intermediates. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 143–155; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20146 相似文献
49.
Choshi T Uchida Y Kubota Y Nobuhiro J Takeshita M Hatano T Hibino S 《Chemical & pharmaceutical bulletin》2007,55(7):1060-1064
An asymmetric synthesis of the core carbazole structure, 6-desprenyl-carquinostatin 3 and 6-descycloavandulyl-lavanduquinocin 3, toward a total synthesis of carquinostatin A (1) and lavanduquinocin (2), has been established. Lipase QLM (Meito) catalyzed enantioselective acetylation of the racemic alcohol 6 gave the (-)-acetate 7 and the (+)-alcohol 6 with high enantioselectivity. The absolute stereochemistry of the (-)- and (+)-alcohol 6 have been determined to be R- and S-configurations, respectively, by the advanced Mosher method. In the same manner, the (-)-acetate 13 and the (+)-alcohol 12 have been obtained from the racemic alcohol 12. The (R)-(-)-acetate 13, derived from the (R)-(-)-acetate 7, was the same as the (-)-acetate 13, which has been determined to be (R)-configuration. Oxidation of the (R)-(-)-acetate 13 followed by hydrolysis afforded (R)-(-)-6-desprenyl-carquinostatin [and (R)-(-)-6-descycloavandulyl-lavanduquinocin] 3. In addition, oxidation of the (S)-(+)-alcohol 12 provided (S)-(+)-3, which is the enantiomer of 6-desprenyl-carquinostatin A (R)-(-)-3. 相似文献
50.
Taniguchi S Kuroda K Doi K Tanabe M Shibata T Yoshida T Hatano T 《Chemical & pharmaceutical bulletin》2007,55(2):268-272
Gambir, the aqueous extract from Uncaria gambir (Rubiaceae), has been used as an astringent medicine in Asian countries. Investigation of the constituents in the extract led to the isolation of four chalcane-flavan dimers, gambiriin A1 (6), A2 (7), B1 (8), and B2 (9), in addition to (+)-catechin (1), (+)-epicatechin (2), and dimeric proanthocyanidins, procyanidin B1 (3), procyanidin B3 (4), and gambiriin C (5). The spectroscopic and chemical data obtained in the present study indicated that their previously proposed structures 6a, 7a, 8a, and 9a should be revised to 6, 7, 8, and 9, respectively. 相似文献