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41.
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Homogenization of geographical variants at the nontranscribed spacer of rDNA in Drosophila mercatorum 总被引:2,自引:0,他引:2
rDNA nontranscribed spacer (NTS) lengths of Drosophila mercatorum have been
measured in individuals from several geographic regions. Individuals from
the different geographic subpopulations share some length fragments but are
in general distinct. The length differences, both within and between
individuals, arise from different copy numbers of a 250-bp repeating unit
that is localized to one part of the NTS. In addition to the length
differences caused by the 250-bp repeat, there is a Y chromosome
(male)-specific length variant elsewhere in the NTS that is approximately
70 bp shorter than the NTS fragment from the X chromosome. Sexual
dimorphism seems to be present in all Drosophila. Also, D. mercatorum has
fewer NTS length variants per individual than does D. melanogaster while
possessing comparable levels of restriction- site polymorphism. The
mechanisms that may cause this pattern of variation are selection, gene
conversion, and unequal recombination.
相似文献
43.
Katarzyna Grychowska Rafał Kurczab Paweł Śliwa Grzegorz Satała Krzysztof Dubiel Mikołaj Matłoka Rafał Moszczyński-Pętkowski Jerzy Pieczykolan Andrzej J. Bojarski Paweł Zajdel 《Bioorganic & medicinal chemistry》2018,26(12):3588-3595
Based on pyrroloquinoline scaffold bearing 5-HT2C agonists, a series of arylsulfonamide derivatives of 1H-pyrrolo[2,3-f]quinoline and 1H-pyrrolo[3,2-h]quinoline, substituted at position 3 with tetrahydropyridine, were synthesized and evaluated in vitro for their affinity for 5-HT6 receptors. A structure–activity relationship study showed that the 1H-pyrrolo[3,2-h]quinoline scaffold was more favorable for 5-HT6R binding than the 1H-pyrrolo[2,3-f]quinoline one, suggesting dependence upon the type of condensation of the pyrrole and quinoline rings. As revealed by quantum-chemical calculations and molecular dynamic studies, position of the quinoline nitrogen atom in the planar pyrroloquinoline skeleton might affect the spatial orientation of the arylsulfonyl fragment, as a result of structure stabilization by internal hydrogen bonds. 相似文献
44.
The influence of optimization target selection on the structure of arterial tree models generated by constrained constructive optimization 总被引:1,自引:1,他引:0
W Schreiner F Neumann M Neumann A End SM Roedler S Aharinejad 《The Journal of general physiology》1995,106(4):583-599
The computational method of constrained constructive optimization was used to generate complex arterial model trees by optimization with respect to a target function. Changing the target function also changes the tree structure obtained. For a parameterized family of target functions a series of trees was created, showing visually striking differences in structure that can also be quantified by appropriately chosen numerical indexes. Blood transport path length, pressure profile, and an index for relative segment orientation show clear dependencies on the optimization target, and the nature of changes can be explained on theoretical grounds. The main goal was to display, quantify, and explain the structural changes induced by different optimization target functions. 相似文献
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Quantitative analysis of organophosphorus pesticides in freshwater using an optimized firefly luciferase‐based coupled bioluminescent assay 下载免费PDF全文
In this paper, a coupled bioluminescent assay, relying on the coupling of the enzymes acetylcholinesterase, S‐acetyl‐coenzyme A synthetase and firefly luciferase, for the detection and quantitation of organophosphorus pesticides, is presented. Using malathion as a model organophosphorus pesticide, the assay was optimized through statistical experimental design methodology, namely Plackett–Burman and central composite designs. The optimized method requires only 20 μL of sample. The linear range for the assay was 2.5–15 μM of malathion, with limits of detection and quantitation of 1.5 and 5.0 μM, respectively. This simple, fast and robust method allows samples to be analyzed at room temperature and without any pretreatment. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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