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291.
Evaluation of immunodiagnostic antigens in the excretory-secretory products of Fasciola hepatica 总被引:2,自引:0,他引:2
The metabolic antigens of F. hepatica have been shown to be a source of potential immunodiagnostic antigens. We have fractionated F. hepatica excretory-secretory (ES) antigens by conventional gel filtration and HPLC, analyzed these fractions in PAGE, and evaluated their immunogenicity by ELISA with sera from experimentally infected rabbits to identify potential serodiagnostic antigens for fascioliasis. A fraction enriched in high molecular weight components of ca. 150-160 kDa was found to be very reactive with sera from early fascioliasis. This fraction was successfully adapted to the DOT-ELISA, where titers up to 1:16,000 still appeared visually as positive. Both acute and chronic fascioliasis sera also recognized, in the enzyme-linked immunoelectrotransfer blot technique (EITB), prominent 25-30-kDa polypeptides that have previously been shown to be recognized by infected rabbits, cows, and sheep. We have therefore employed conventional gel filtration and HPLC gel exclusion chromatography as a 1-step procedure to obtain fractions enriched in antigens recognized in early fascioliasis. In addition, these antigens have been successfully applied to a sensitive, visual immunodiagnostic technique that can be easily employed in field studies. 相似文献
292.
Induction of translational errors (misreading) by tuberactinomycins and capreomycins 总被引:1,自引:0,他引:1
Pedro Marrero María Jesús Cabañas Juan Modolell 《Biochemical and biophysical research communications》1980,97(3):1047-1042
The well characterized translocation inhibitor viomycin (=tuberactinomycin B) promotes translational errors (misreading) in an in vitro system from Escherichia coli. It strongly stimulates both the binding of noncognate Tyr-tRNA to poly(U)-programmed ribosomes and the subsequent synthesis of acPhe(Tyr)n-tRNA (). The closely related antibiotics capreomycin and tuberactinomycins A,N and O also inhibit translocation and induce misreading. 相似文献
293.
Rayza González Taletha Laudat Mayda Arzola Roberto Méndez Pedro Marrero Lázaro E. Pulido Bernardo Dibut José Carlos Lorenzo 《In vitro cellular & developmental biology. Plant》2011,47(3):387-390
Pineapple is one of the most important tropical fruits, but the availability of planting material is insufficient to agricultural
demands. Therefore, several pineapple micropropagation protocols have been developed. However, acclimatization of in vitro plants continues to take a prolonged period. Biofertilizers have been found as safe alternatives to improve the agricultural
performances of many crops. This study highlights some of the effects of the application of Azotobacter chroococcum (INIFAT5 strain) on in vitro pineapple plants during acclimatization. The bacteria were sprayed immediately after transplanting to the ex vitro environment; the plants were then sprayed every 4 wk. A control group of plants was established. Subsequently, after 5 mo,
the evaluated variables included fresh and dry plant weight, plant height (cm), and root length (cm). The anatomy of middle-aged
leaves and roots was also studied: transversal thickness and width of cuticle, epidermis, hypodermis, aquiferous parenchyma,
and photosynthetic parenchyma. Thickness of root exoderm, external cortex, internal cortex, and stele were also evaluated.
In general, the INIFAT5 strain improved the plant development. Results showed that the bacteria significantly provoked changes
in the plant fresh weight, the thickness of the leaf abaxial and adaxial cuticles, and the root exoderm width. Contrastingly,
A. chroococcum did not affect the thickness of the leaf photosynthetic parenchyma. 相似文献
294.
295.
Poly-γ-l-glutamic acid was synthesized in optimized fermentor cultivation ofBacillus licheniformis. The polypeptide obtained was esterified using benzyl- and butylbromides. Benzyl esters with 30, 60 and 100% degree of esterification
were prepared. Solubility of the products in dimethyl sulfoxide, chloroform, methanol and in water was significantly different
from these ones of original polymer. 相似文献
296.
297.
Juli Caujapé-Castells José Naranjo-Suárez Isabel Santana Mario Baccarani-Rosas Nereida Cabrera-García Manuel Marrero Eduardo Carqué Ricardo Mesa 《Plant Systematics and Evolution》2008,273(3-4):191-199
We examined the levels and apportionment of genetic variation of the 11 known subpopulations of Atractylis preauxiana at 95 RAPD loci to help streamline a conservation strategy for this Canarian endemic taxon, which is in a critical situation because of the constant exposure of plants to intensive, uncontrolled anthropic action in the last few decades. Our results revealed low genetic variation levels that match with the general picture of demographic and habitat degradation that this taxon is undergoing. Although geographic isolation between Tenerife and Gran Canaria is an effective barrier to gene flow, genetic heterogeneity within islands is also substantial, plausibly due to the negative impact of fragmentation on genetic variation. Our genetic results, together with declining population sizes, poor seedling survival, and recent population extinctions, compellingly indicate that A. preauxiana is undergoing an extinction ratchet, whereby every further local extinction will add up to the probability of total species’ extinction. Our genetic results suggest that mitigating the deleterious consequences of this effect entails urgent mixed reinforcements of all sub-populations with sub-populations from the same island and urgent translocation of the two sub-populations from Tenerife that are doomed to extinction to ecologically suitable areas, together with seed collection and preservation in a convenient ex situ banking facility. 相似文献
298.
- Deceptive pollination has been reported in the genus Aristolochia, but the floral biology and pollination strategy of A. bianorii, an endemic of the Balearic Islands, have not yet been studied. Here, we investigated floral anthesis, mating system, pollinators and volatile organic compounds (VOCs) emitted by its flowers.
- Flower buds were marked and monitored daily to define floral stages and their duration. Experimental bagging and hand-pollination were performed to test for autonomous self-pollination, induced self-pollination and cross-pollination. Flowers were collected to analyse the presence of entrapped pollinators. VOCs emitted by flowers were evaluated by means of solid phase microextraction followed by immediate GC–MS.
- Anthesis lasted between 63 and 96 h, and the species exhibited autonomous self-pollination with moderate inbreeding depression. Pollinators were mainly females of Oscinomorpha longirostris (Diptera; Chloropidae). The number of pollinators inside flowers was affected by floral stage and time of flowering. The most common VOCs were alkanes, oximes, esters, alkenes, cyclic unsaturated hydrocarbons, isocyanates, amides and carboxylic acids.
- Aristolochia bianorii can set seed by autonomous self-pollination, in contrast to other Aristolochia species, in which both protogyny and herkogamy prevent autonomous self-pollination. However, the species may encourage cross-pollination by attracting female chloropid flies though emission of floral scents that may mimic an oviposition site and, possibly, freshly killed true bugs (i.e. Heteroptera). In conclusion, A. bianorii promotes cross-pollination, but delayed autonomous self-pollination assures reproductive success in the putative absence of pollinators.