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121.
L.M.V. Tillekeratne D.T. Jayamanne K.D.V. Weerasuria A.A.Leslie Gunatilaka 《Phytochemistry》1982,21(2):476-478
A detailed chemical investigation of extracts of the bark, leaf and timber of Horsfieldia iryaghedhi collected in Sri Lanka, led to the isolation of (+)-asarinin, dodecanoylphloroglucinol and (?)-dihydrocubebin. 相似文献
122.
Gisele B. Messiano 《Phytochemistry》2009,70(5):590-6648
Holostylis reniformis biosynthesizes 8-8′ linked lignans without 9,9′-oxygenation. To elucidate the biosynthetic pathways to these lignans, the reputed precursors [U-14C]phenylalanine, [9-3H1]coniferyl alcohol, and [9-3H1]isoeugenol were administered to roots of the plant, which led to the incorporation of 3H and 14C into ten 2,7′ linked-lignans (aryltetralone lignans) and two 7,7′-epoxylignans (furan lignans). These administration experiments demonstrated that the lignans were propenylphenol-derived and that H. reniformis can exhibit regioselective control over radical-radical coupling (via isoeugenol radicals). Regiospecific control over propenylphenol-derived lignan biosynthesis was observed, together with diastereoselective control of C2-C7′ bond formation for the aryltetralone lignans (7′R). These experiments provide evidence that isoeugenol is a biosynthetic intermediate to the aryltetralone and furan lignans. 相似文献
123.
Massuo J. Kato Hipólito F. Paulino Fo Massayoshi Yoshida Otto R. Gottlieb 《Phytochemistry》1985,25(1):279-280
Fruits of Virola elongata contain, besides the furofuranoid lignans eudesmin, epieudesmin and fargesin, the aryl-benzyl-methyl tetrahydrofuran neolignans magnostellins A and C. The absolute configuration of the magnostellins was detennined. 相似文献
124.
Xian-Huan Zhang Mr. Zhao Lu Dr. Zhi-Yuan Li Nan Fu Prof. Dr. Rui Zhan 《化学与生物多样性》2023,20(7):e202300549
Seven lignans were isolated from 70 % aqueous acetone extracts of the twigs and leaves of Horsfieldia kingii. Among these, new compounds 1 – 3 were identified by spectroscopic techniques, with horsfielenigans A and B ( 1 and 2 ) being particularly noteworthy for their rare β-benzylnaphthalene skeleton, where compound 1 contains an oxabicyclo[3,2,1]octane moiety. In vitro evaluation of bioactivity against nitric oxide (NO) production in LPS-activated RAW264.7 macrophages revealed inhibitory effects by 1 (IC50=7.3 μM) and 2 (IC50=9.7 μM). 相似文献
125.
The antifeedant activity of a series of lignan lactones, hemiacetals, ethers, and alcohols derived from yatein and cubebin, together with structurally related phenylpropanoids and phenolics possessing a methylenedioxyphenyl (piperonyl) moiety, was tested against selected stored products pests: Sitophilus granarius L. (Coleoptera: Curculionidae), Tribolium confusum Duv. (Coleoptera: Tenebrionideae), and Trogoderma granarium Ev. (Coleoptera: Dermestridae). The relation between molecular structure and antifeedant activity was examined and implication of the piperonyl moiety is assessed. The compounds represent either natural substances isolated from plants (Libocedrus yateensis Guillaumin and Piper cubeba L.) or their structural analogues prepared by simple chemical transformations as well as compounds selected from commercially available sources. Natural lignan lactones with methoxy and/or methylenedioxy substituents showed significant activity that is strong enough to affect plant - insect interactions. Presence of polar substituents, especially hydroxy or glycosyl groups, often reduce the activity. Non-polar substituents, such as methoxy or methylenedioxy groups, enhance the activity not only in lignans but also in simple phenylpropanoids. The most active compound was synthetic piperonylbutoxide. 相似文献
126.
Antonio G. Gonzalez Braulio M. Fraga Melchor G. Hernandez Javier G. Luis Francisca Larruga 《Biochemical Systematics and Ecology》1979,7(2):115-120
Nine species, drawn from two sections of the genus Sideritis (Labiatae) from the Canary Islands were examined. Terpenoids, sterols, flavonoids, coumarins and lignans were isolated. From the chemosystematic point of view the Sideritis species were divided into three groups. The first was formed by S. argosphacelus and S. macrostachya, the second by S. bolleana, S. canariensis, S. candicans, S. candicans var. TFC 3890, S. dasygnaphala and S. dendrochahorra, while the third contained S. gomerae and S. cabrerae. 相似文献
127.
Julianne K. Hwang Syed G.A. Moinuddin Laurence B. Davin Norman G. Lewis 《Chirality》2020,32(6):770-789
Two western red cedar pinoresinol-lariciresinol reductase (PLR) homologues were studied to determine their enantioselective, substrate versatility, and kinetic properties. PLRs are downstream of dirigent protein engendered, coniferyl alcohol derived, stereoselective coupling to afford entry into the 8- and 8′-linked furofuran lignan, pinoresinol. Our investigations showed that each PLR homolog can enantiospecifically metabolize different furofuran lignans with modified aromatic ring substituents, but where phenolic groups at both C4/C4′ are essential for catalysis. These results are consistent with quinone methide intermediate formation in the PLR active site. Site-directed mutagenesis and kinetic measurements provided additional insight into factors affecting enantioselectivity and kinetic properties. From these data, PLRs can be envisaged to allow for the biotechnological potential of generation of various lignan skeleta, that could be differentially “decorated” on their aromatic ring substituents, via the action of upstream dirigent proteins. 相似文献
128.
This paper summarises the results of three projects. The first is concerned with developing general routes for the synthesis of lignans. In particular, two routes involving tandem conjugate addition reactions and Diels Alder reactions respectively that have been used to synthesise podophyllotoxin derivatives are described. The second project is concerned with the asymmetric synthesis of lignans and involves the application of these reactions, with the introduction of a menthyloxy group as a chiral auxiliary, to achieve the asymmetric synthesis of podophyllotoxin derivatives. The third project is concerned with the attempted biomimetic syntheses of podophyllotoxin derivatives using oxidative coupling reactions. Attention is focussed primarily on the use of hypervalent iodine reagents, which yield stegane and isostegane derivatives rather than podophyllotoxin derivatives. Other examples of biaryl coupling leading to stegane and isostegane derivatives are included, and other examples of lignan synthesis involving hypervalent iodine reagents are also described.
Abbreviations: DDQ – 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; DMAD – dimethyl acetylenedicarboxylate (dimethyl butynedioate); PIDA – phenyliodonium diacetate, iodobenzene diacetate; PIFA – phenyliodonium bis(trifluoroacetate), [bis(trifluoroacetoxy) iodobenzene]; Ra-Ni – Raney nickel; TBAF – tetrabutylammonium fluoride; TBDMS –t-butyldimethylsilyl; TFA – trifluoroacetic acid; TFAA – trifluoroacetic anhydride; TFE – 2,2,2-trifluoroethanol; TTFA – thallium(III) trifluoroacetate. 相似文献
129.
The wood of Conocarpus erectus contains conocarpol and 2′-methoxyconocarpol, simple 1,4-diarylbutane-type lignans, and conocarpan, a lignan of the dehydrodi-isoeugenol type. 相似文献