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21.
Two basic male morphs occur in several species of the family Acaridae: heteromorphic fighters, possessing a thickened and sharply terminated third pair of legs, and homeomorphic males with unmodified legs. We compared major life-history traits of the two morphs in the bulb mite, Rhizoglyphus robini. We found no significant differences in development time or virility, but homeomorphic males lived 23% longer than heteromorphs. We discuss the possibility that the trade-off between longevity and adaptation for fighting maintains genetic variation for the male morph in the studied species. 相似文献
22.
23.
Agata Plesnar Bielak Anna M. Skrzynecka Krzysztof Miler Jacek Radwan 《Evolution; international journal of organic evolution》2014,68(7):2137-2144
Intralocus sexual conflict (IASC) arises when fitness optima for a shared trait differ between the sexes; such conflict may help maintain genetic variation within populations. Sex‐limited expression of sexually antagonistic traits may help resolve the conflict, but the extent of this resolution remains a subject of debate. In species with alternative male reproductive tactics, unresolved conflict should manifest more in a more sexually dimorphic male phenotype. We tested this prediction in the bulb mite (Rhizoglyphus robini), a species in which aggressive fighters coexist with benign scramblers. To do this, we established replicated lines in which we increased the proportion of each of the alternative male morphs using artificial selection. After approximately 40 generations, the proportion of fighters and scramblers stabilized at >0.9 in fighter‐ and scrambler‐selected lines, respectively. We then measured several female fitness components. As predicted by IASC theory, female fecundity and longevity were lower in lines selected for fighters and higher in lines selected for scramblers. This finding indicates that sexually selected phenotypes are associated with an ontogenetic conflict that is not easily resolved. Furthermore, we suggest that IASC may be an important mechanism contributing to the maintenance of genetic variation in the expression of alternative reproductive tactics. 相似文献
24.
25.
Amany K. Ibrahim Mohamed M. Radwan Safwat A. Ahmed Desmond Slade Samir A. Ross Mahmoud A. ElSohly Ikhlas A. Khan 《Phytochemistry》2010,71(8-9):1014-1019
Microbial metabolism of cannflavin A (1) and B (2), two biologically active flavonoids isolated from Cannabis sativa L., produced five metabolites (3–7). Incubation of 1 and 2 with Mucor ramannianus (ATCC 9628) and Beauveria bassiana (ATCC 13144), respectively, yielded 6″S,7″-dihydroxycannflavin A (3), 6″S,7″-dihydroxycannflavin A 7-sulfate (4) and 6″S,7″-dihydroxycannflavin A 4′-O-α-l-rhamnopyranoside (5), and cannflavin B 7-O-β-d-4?-O-methylglucopyranoside (6) and cannflavin B 7-sulfate (7), respectively. All compounds were evaluated for antimicrobial and antiprotozoal activity. 相似文献
26.
Radwan J 《Experimental & applied acarology》2007,42(3):151-158
Whether benefits of mate choice accrued by females outweigh costs associated with sexual selection remains largely unresolved.
The ‘good genes’ perspective, posing that mate choice benefits females genetically has been challenged by the arguments that
sexual selection is driven mostly by direct costs and inter-sexual conflict. Here, I present an overview of experimental tests
of predictions of good genes and sexual conflict mechanisms in the bulb mite Rhizoglyphus robini. 相似文献
27.
In recent years, the bank voleMyodes glareolus (Schreber, 1780) has emerged as a model system for parasitological, behavioural and ecological studies and seems ideally
suited to address questions concerning the importance of MHC variation at individual and population levels. Here, we provide
the first extensive survey of sequence variation in the MHC class II DRB genes in this species. Among 34 analysed voles we
found 15 unique sequences, representing most likely two loci, at least one of them expressed. Despite very high overall sequence
divergence, particularly in the Antigen Binding Sites (ABS), we detected signatures of positive selection that has been acting
on DRB in the bank vole. Phylogenetic analysis demonstrated that the bank vole DRB alleles do not form a monophyletic group
but are intermingled with other rodent alleles that is consistent with long-term persistence of ancient allelic lineages maintained
through balancing selection. Our sequence data will forward the design of efficient genotyping methods, which will permit
testing hypotheses pertaining to the ecological causes and consequences of MHC variation in the bank vole. 相似文献
28.
29.
Awwad Abdoh Radwan 《Bioinformation》2015,11(2):63-66
cGMP-binding cGMP-specific PDE, PDE5 plays a key role in the hydrolysis of cyclic guanidine monophosphate. Because cGMP
mediates vascular functions, a PDE5 inhibitor that elevates cGMP level is an attractive means for vasodilatation and treatment of
erectile dysfunction. In this paper we report the elucidation of the common pharmacophore hypothesis of different classes of PDE5
inhibitors. Using LigandScout program, pharmacophore modelling studies were performed on prior reported potent PDE5
inhibitors with a variety of scaffolds in order to identify one common set of critical chemical features of these PDE5 inhibitors 1-52.
The best pharmacophore model, model-1, characterized by four chemical features: one aromatic ring, one hydrophobe, one
hydrogen acceptors and one hydrogen donor. Using Dock6 program, docking studies were performed in order to investigate the
mode of binding of these compounds. The molecular docking study allowed confirming the preferential binding mode of different
classes of PDE5 inhibitors inside the active site. The obtained binding mode was as same as that of vardenafil, X-ray ligand with
different orientation with varied PDE5 inhibitors׳ scaffold. 相似文献
30.
Joel Park Osman Radwan Bruce Martin Henry T Wilkinson Hanafy M Fouly 《Journal of Phytopathology》2011,159(4):317-320
Take‐all disease is caused by Gaeumannomyces graminis, (Sacc.) Arx & D. Olivier, a soil‐borne fungus, which colonizes the root and crown tissue of many members of the Poaceae plant family. This fungus is able to grow along the surface of roots as darkly pigmented runner hyphae, which has the ability to penetrate the root. Here, we describe a genetic transformation of G. graminis var. graminis by using polyethylene glycol (PEG)‐based protoplast transformation. Fungus cells were transformed with a plasmid, pHPG, containing the gusA reporter gene that codes for β‐glucuronidase (GUS) and the hph gene for hygromycin resistance as the selectable marker. A de novo transformant selection assay was developed to identify the putative transformants that were expressing the hph gene. In addition, the transformed cells maintained the ability to infect the plant tissues. The GUS‐expressing fungus can be used to study fungal infection processes including fungal penetration, colonization and the role(s) of melanin during pathogenesis. Thus, this study is the first report of G. graminis var. graminis transformed with a visibly detectable reporter gene that provides a useful tool to a better understanding of host–Gaeumannomyces interactions. 相似文献