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The molecular basis of mammalian sperm capacitation is unique in that, it is associated with a protein kinase A (PKA) dependent upregulation of protein tyrosine phosphorylation. Therefore, PKA activity during capacitation would be crucial for the downstream events of protein tyrosine phosphorylation, and mechanisms may exist to ensure that PKA phosphorylates its specific substrate. This could be achieved by bringing PKA close to its substrate, a function normally carried out by an A-kinase anchoring protein (AKAP). We showed previously that cauda epididymidal spermatozoa of hamster undergo a capacitation-dependent increase in protein tyrosine phosphorylation. In the present study, evidence is provided that two major tyrosine phosphorylated proteins of molecular weight 97 and 83 kDa are the hamster homologues of mouse pro-AKAP82 and AKAP82, and have been designated as hamster pro-AKAP83 and AKAP83 respectively. Hamster AKAP83 resembled the mouse AKAP82 with respect to its molecular weight, pI (pH 5-5.5) and cDNA and amino acid sequences. Sequence analysis indicated that the primary structure of pro-AKAP83 was highly conserved and exhibited 91% identity with mouse and rat AKAP82. Further, the functional domains, namely the region involved in binding the regulatory subunit of PKA and the proteolytic cleavage site between pro-AKAP83 and AKAP83, were identical with that observed in rat and mouse pro-AKAP82 and AKAP82. Immunoblot analysis using polyclonal hamster anti-AKAP83 antibodies indicated that AKAP83 was present both in caput and cauda epididymidal spermatozoa. The antibody also identified the pro-AKAP82 and AKAP82 in mouse caput and cauda epididymidal spermatozoa. Immunofluorescence studies indicated that AKAP83 in hamster spermatozoa was localized along the length of principal piece of the tail. It was also demonstrated that hamster pro-AKAP83/AKAP83 gene expression was testis specific and was not expressed in other organs in either sex. This is the first report implicating AKAP in capacitation in rodents. 相似文献
993.
Sahoo Sripati Abhiram Jha Zenu Verulkar Satish B. Srivastava Ashish K. Suprasanna Penna 《Plant Cell, Tissue and Organ Culture》2019,137(1):187-192
Plant Cell, Tissue and Organ Culture (PCTOC) - The study provides high-throughput protocol for ploidy determination which may accelerate the production of double haploids in rice. Advancements in... 相似文献
994.
Summary Snails and nematodes, the potential cyanobacterial grazers, differ in their choice for cyanobacterial diet. Snails prefer
non-mucilaginous forms while nematodes prefer mucilaginous forms. Such differences in feeding choice between the cyanobacteria
suggests that it may not be possible to select strains of diazotrophic cyanobacteria that are resistant to all grazers. The
potential consumption of cyanobacteria at an average field density of 20,000 snails ha−1 was estimated to be about 50 kg (fresh weight) ha−1 day−1. Dorylamus sp. was most dominant nematode associated with cyanobacterial consumption. Phytoextracts of neem (Azadirachta indica), bel (Aegle marmelos) and tobacco (Nicotiana tabacum) were effective in controlling these cyanobacterial grazers. The minimum concentration of neem, bel and tobacco phytoextract
in water for 100 % mortality of snails were 0.1, 2.0 and 0.05%, respectively. However, trepellent level was only 0.01% for
neem and tobacco phytoextract. Complete mortality of nematode (Dorylamus spp.) required a higher concentration level (2%) even in the most effective tobacco phytoextract. Lower levels of phytoextract
(0.1%) were found to stimulate growth and nitrogen fixation of cyanobacteria. Application of these plant biomasses resulted
in significant increase in cyanobacterial acetylene-reducing activity (ARA) and rice yield and a significant decrease in snail
and nematode population. Augmentation of cyanobacterial acetylene-reducing activity was two to three times higher in comparison
to the control in both the years of experimentation. Rice yield also increased between 3.8 and 58.5% over the control, depending
on the quantity and nature of plant biomass. Tobacco waste was significantly superior in comparison to neem and bel biomass
as carrier of cyanobacterial culture. 相似文献
995.
Ajay Kumar Jha Surya Prakash Neeru Jain Kanan Nanda S. C. Gupta 《In vitro cellular & developmental biology. Plant》2002,38(5):430-434
Summary Adventitious shoots were induced from the hypocotyl explants derived from 12–15-d-old seedlings of Sesbania rostrata on Nitsch's medium (Nitsch, 1969) supplemented with 1 mgl−1 (4.4 μM), of N6-benzylademine (BA). A maximum of 5.9±3.4 shoots per explant in 100% of cultures were obtained. The BA treatment for different
time durations (1, 3, 5, 7, 10, 17, 21, or 30 d) exhibited significant variation in the caulogenic potential of the explants.
BA treatment for 10–17 d proved optimum for the response. Although at all concentrations of kinetin the explants developed
multiple shoots, they were malformed. Sucrose at 3% exhibited the development of the maximum of 3.5±0.9 shoots per explant
with an average shoot length of 4.7±3.9 cm. Among the different carbon sources, i.e., fructose, galactose, maltose, mannose,
and sucrose at 3% (w/v), sucrose supported the best caulogenic response. The role of various other factors (viz. size, orientation
of explant, and seedling age) on the caulogenic response of the hypocotyl explants of S. rostrata were also studied. The shoot development in all cases was accompanied by the development of moderate to profuse callus at
the basal cut end of the explant. The in vitro-regenerated shoots produced roots when transferred to half-strength MS medium (Murashige and Skoog, 1962) supplemented with
3% sucrose and 1 mgl−1 (4.9 μM) indole-3-butyric acid (IBA). The developed plantlets were transferred to the field after an initial acclimatization
period of 3–4 mo. Such transferred plants produced flowers and fruits in the field and exhibited the development of prominent
and organized stem nodules. 相似文献
996.
Automatic antifungal activity analyzing system on the basis of dynamic growth process of a single hypha 总被引:3,自引:0,他引:3
Satoru Yamada Jinan Cao Osao Sumita Kikuo Kurasawa Hiroshi Kurata Kibong Oh Hideaki Matsuoka 《Mycopathologia》1992,118(2):65-69
A system for the evaluation of antifungal activity of volatile compounds has been developed that is based on dynamic growth of a single hypha. The newly developed system is composed of a reaction vessel under a microscope, automatic stage, charge coupled device (CCD) camera, TV monitor, video tape recorder (VTR), and a microcomputer. A fungus was inoculated in the reaction vessel containing agar medium and then was treated with an antifungal reagent in the gas phase either in batch or flow reaction manner. The apex of a growing hypha displayed on a TV monitor was followed automatically. From the ratio of the growth rate under exposure of a reagent (UEXPO) to the growth rate before the exposure (UPRE), the antifungal activity was expressed quantitatively. 相似文献
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