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641.
642.
Involvement of nitric oxide signaling in mammalian Bax-induced terpenoid indole alkaloid production of <Emphasis Type="Italic">Catharanthus roseus</Emphasis> cells
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Bax, a mammalian pro-apoptotic member of the Bcl-2 family, has been demonstrated to be a potential regulatory factor for plant
secondary metabolite biosynthesis recently. To investigate the molecular mechanism of Bax-induced secondary metabolite biosynthesis,
we determined the contents of nitric oxide (NO) of the transgenic Catharanthus roseus cells overexpressing a mouse Bax protein and checked the effects of NO specific scavenger 2,4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide
(cPITO) on Bax-induced terpenoid indole alkaloid (TIA) production of the cells. The data showed that overexpression of the
mouse Bax in C. roseus cells triggered NO generation of the cells. Treatment of cPITO not only inhibited the Bax-triggered NO burst but also suppressed
the Bax-induced TIA production. The results indicated that the mouse Bax might activate the NO signaling in C. roseus cells and induce TIA production through the NO-dependent signal pathway in the cells. Furthermore, the activities of nitric
oxide synthase (NOS) were significantly increased in the transgenic Bax cells as compared to those in the control cells, showing that the mouse Bax may induce NOS of C. roseus cells. Treatment of the transgenic Bax cells with NOS inhibitor PBITU blocked both Bax-induced NO generation and TIA production, which suggested that the mouse
Bax might trigger NO generation and TIA production through NOS. However, the NOS-like activities and NO generation in the
transgenic Bax cells did not match kinetically and the Bax-induced NOS-like activity was much later and lower than NO production. Moreover,
the Bax-induced NO generation and TIA production were only partially inhibited by PBITU. Thus, our results suggested that
the Bax-induced NO production and secondary metabolite biosynthesis in C. roseus cells was not entirely dependent on NOS or NOS-like enzymes. 相似文献
643.
Rangana Sinha Maidul HossainGopinatha Suresh Kumar 《Biochimica et Biophysica Acta (BBA)/General Subjects》2007
A key step in the rational design of new RNA binding small molecules necessitates a complete elucidation of the molecular aspects of the binding of existing molecules to RNA structures. This work focuses towards the understanding of the interaction of a DNA intercalator, quinacrine and a minor groove binder 4′,6-diamidino-2-phenylindole (DAPI) with the right handed Watson–Crick base paired A-form and the left-handed Hoogsteen base paired HL-form of poly(rC)·poly(rG) evaluated by multifaceted spectroscopic and viscometric techniques. The energetics of their interaction has also been elucidated by isothermal titration calorimetry. Results of this study converge to suggest that (i) quinacrine intercalates to both A-form and HL-form of poly(rC)·poly(rG); (ii) DAPI shows both intercalative and groove-binding modes to the A-form of the RNA but binds by intercalative mode to the HL-form. Isothermal calorimetric patterns of quinacrine binding to both the forms of RNA and of DAPI binding to the HL-form are indicative of single binding while the binding of DAPI to the A-form reveals two kinds of binding. The binding of both the drugs to both conformations of RNA is exothermic; while the binding of quinacrine to both conformations and DAPI to the A-form (first site) is entropy driven, the binding of DAPI to the second site of A-form and HL-conformation is enthalpy driven. Temperature dependence of the binding enthalpy revealed that the RNA–ligand interaction reactions are accompanied by small heat capacity changes that are nonetheless significant. We conclude that the binding affinity characteristics and energetics of interaction of these DNA binding molecules to the RNA conformations are significantly different and may serve as data for the development of effective structure selective RNA-based antiviral drugs. 相似文献
644.
645.
Lienkonine, a further alkaloid from Corydalis ochotensis, has been isolated and elucidated as (?)-2,3,10-trimethoxy-8α-methyl-13aαH-berbine-9-ol by the spectral data and chemical properties. 相似文献
646.
The structure of a new hexacyclic carbazole alkaloid from Murraya koenigii has been shown to be 9a,10,11,12,13,13a-hexahydro-5,9,9,12-tetramethyl-1 相似文献
647.
648.
Phytochemicals and anti-inflammatory activity were investigated in the leaves of Pellacalyx saccardianus from the Rhizophoraceae family. The powdered leaves were extracted using methanol in a soxhlet extractor. Purification of the methanol extract yielded two new compounds, (3S)(6R)-3-(4′-hydroxybenzyl)-6-(6″-hydroxyphenethyl)-2,2-dimethyl-piperidin-4-one and 1,2-O-(1-methylethylidene)fucoside, together with six known compounds, β-amyrin palmitate, squalene, 24-ethylcholesta-5,22,25-trien-3β-ol, 5R-hydroxy-1,7-bis(5-hydroxyphenyl)heptan-3-one, 1,7-bis(4-hydroxyphenyl)hept-4-en-3-one and methyl-l-fucoside. An anti-inflammatory assay using COX-2 revealed that β-amyrin palmitate possessed the highest inhibitory effect (96.8%) at the lowest concentration (0.01 μM), which was higher than that of the positive controls, resveratrol (90.2%, 0.01 μM) and indomethacin (79.20%, 100 μM). This is the first report on the isolation of phytochemicals from the leaves of P. saccardianus and their anti-inflammatory activity. 相似文献
649.
William Gaffield Rosalind Y. Wong Robert E. Lundin Richard F. Keeler 《Phytochemistry》1982,21(9):2397-2400
Spectral techniques have established the structure of muldamine from Veratrum californicum as (22S, 25S)-22,26-epiminocholest-5-ene-3β,16 相似文献
650.
Sisi Liu Pei Deng Yihong Long Shushu Yang Junshuo Zhu Kunsheng Li Changjiangsheng Lai Weiran Yang Jinlong Chen 《化学与生物多样性》2021,18(10):e2100388
Former study suggests alkaloids from herbs of Aconitum genus plants possess excellent bioactivities, which exert great value for related deeper chemical constituent investigation. Herein, chemical isolation was performed and four alkaloids were isolated from Fuzi, of which two were new ones, and the other two were reported NMR data for the first time. Their chemical structures were identified by NMR data, high resolution MS, UV and IR analysis. Additionally, the MS fragmentation patterns were explored, formerly, that of hetisane alkaloid was rarely reported, and fragmentation mechanism of the diagnostic ion was proposed. Based on these fragment pathway, metabolites and metabolic pathways of four compounds were investigated in rat liver microsomes using UPLC−Q/TOF−MS, and dehydrogenation product was firstly found from metabolites of hetisane alkaloid. 相似文献