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991.
J.H. van Wyk 《African Zoology》2013,48(4):253-260
Seasonal morphometric and physiological changes associated with vltellogenesis in the female agamid lizard, Agama atra are described. Vitellogenic activity during August - September marked the onset of the breeding season. It is suggested that at least two clutches were ovulated during the breeding season. Large abdominal fatbodles deposited prior to the winter months were possibly utilized to meet metabolic demands during winter and the onset of vitellogenesis during early spring (August - September). Follicular growth and fatbody deposition coincided with low plasma cholesterol levels. The liver index and total plasma proteins did not show a clear seasonal pattern. Of the seven plasma protein fractions, Fraction 2 (‘human beta-globulin’ mobility) increased during vltellogenesis while the foremost migrating proteins (‘human albumin’ mobility) showed a compensatory decrease. Total plasma calcium levels increased during vitellogenesis. The oviducts remained hypertrophied throughout the breeding season, while progesterone levels increased following each ovulation cycle in the presence of corpora lutea and remained elevated until oviposition. The onset of the second vitellogenic cycle (December) coincided with high progesterone levels. 相似文献
992.
Sessile peritrichs (Ciliophora: Peritricha) were collected from freshwater fish in lakes, rivers, streams and fish-ponds in the Transvaal, South Africa Nine species of the genus Apiosoma Blanchard, 1885 are described, i.e. seven new species; A. caulata sp.n., A. curvinucleata sp.n, A. micralesti sp.n., A. mothlapitsis sp.n., A. obliqua sp.n., A. phiala sp.n. and A. viridis sp.n., and two known species; A. nasal is (Timofeev, 1962) and A. piscícola Blanchard, 1885. One new species of the genus Ambiphrya Baabe, 1952 is described, i.e. A. neobolae sp.n. A new sgenus, Scopulata gen.n. is proposed for species with a broad scopula and compact macronucleus. Two previously described Scyphidia species are incorporated in this genus, i.e. S. dermata (Viljoen & Van As, 1983) comb.n. and S. epibranchialis (Viljoen & Van As, 1983) comb.n., as well as a new species, S. constricta sp.n. Compendiums of all the known fish-associated species of these genera are provided. 相似文献
993.
Breeding success of Pterodroma macroptera, Procellaria aequinoctialis and Pachyptila vittata salvini in three cat-free and three control areas were used to evaluate the effects of cat Felis catus predation on the avifauna of Marion Island. Breeding success of all three species was significantly higher in the combined cat-free areas than in the combined control areas. However, breeding success in one cat-free area failed to show a significant difference from its particular control area, probably as a result of higher skua (Catharacta antarctica) predation inside the cat-free area. Chicks of P. macroptera and P. aequinoctialis were especially vulnerable to cat predation, since cats can enter their nesting burrows. P. macroptera was seriously affected by cat predation because it is the most abundant of only two winter-breeding petrels. Significant changes in the number of nest visits by these petrels during their breeding season followed hatching dates, which in turn were concomitant with, or were followed by significant differences in the combined breeding success between the cat-free and control areas. The cat-free areas show that an elimination of cat predation would still favour the recovery of the petrel population. 相似文献
994.
The attachment of the piscine gill parasite, Ergasilus mirabilis Oldewage & van As, 1987 is described by means of scanning electron microscopy and light microscopy. A variety of sensory structures occur on and around the host contact surface of the parasite and proliferation of gill tissue occurs at the site of attachment. It would appear that this proliferation of host tissue results from the feeding behaviour of the parasite rather than the actual attachment thereof. 相似文献
995.
996.
Carly M. Benefer W. G. van Herk J. S. Ellis R. P. Blackshaw R. S. Vernon M. E. Knight 《Journal of pest science》2013,86(1):19-27
Click beetle larvae (wireworms) are significant crop pests in Europe and North America. In Canada, there are ~30 economically important species which are morphologically difficult to identify, but for which sequence data are lacking. Accurate knowledge of damage-causing species and the population genetics and phylogeography of elaterids will provide insight into their sustainable management. Here, we use interspecific variation in mitochondrial 16S rRNA as a robust method of identification, consider the intra- and interspecific genetic variation of some important Canadian wireworm pests and assess the genetic structure and isolation by distance for a re-emerging major pest species, Hypnoidus bicolor Eschscholtz. Wireworms were sampled from Canada and the USA, identified as morphospecies, and sequenced at the 16S rRNA region (294–442 bp). Within some species unusually high intraspecific genetic distances between samples suggested the possibility of cryptic wireworm species or misidentifications, though this was <1 % for most species. Phylogenetic analyses gave some indication of the likely identity of these ambiguous samples. There was a significant correlation between genetic and geographic distance and significant genetic structuring within and between H. bicolor populations, which appeared to be composed of two species comprising several haplotypes. These data provide a starting point for determining the distribution of damage-causing species throughout Canada. The inclusion of data from other nuclear and mitochondrial loci, and use of sequence data from known adult samples, would further aid identification and relationships of wireworm species. 相似文献
997.
To determine if bifenthrin residues elicit morbidity and surfacing behavior in wireworms, larvae of the dusky wireworm, Agriotes obscurus (Coleoptera: Elateridae) were placed in field soil treated with the pyrethroid insecticide bifenthrin ~1 year previous. Morbidity was immediate and lasted as long as wireworms remained in the soil, disappearing quickly after transfer to clean soil. In 2009, field soil treated 336 days previous with bifenthrin at 340 g AI/ha elicited morbidity symptoms similar to that elicited by soil freshly amended with bifenthrin at 100 g AI, and analysis of the field soil confirmed residual levels of bifenthrin exceeding 100 g AI/ha. In 2010, wireworms placed in field soil treated 343 days previous with bifenthrin at 100, 200, and 300 g AI/ha responded as in 2009, with the degree of morbidity increasing with the rate of insecticide, and with wireworms in a non-feeding state more affected than those in a feeding state at each rate. In both 2009 and 2010, moribund wireworms moved to the soil surface within 1 day of placement in the soil containing residual bifenthrin and remained there until reburied, after which they often resurfaced. To confirm that the bifenthrin residues elicited repellency, wireworms were placed in soil window bioassays containing field soil with residual bifenthrin. Wireworms behaved markedly different upon contacting soil containing the residues than when exposed to untreated soil, both in the presence and absence of an attractant, but were less likely to avoid soil containing residual bifenthrin when attracted by wheat seedlings placed inside it. 相似文献
998.
999.
J. van Hoof 《The Veterinary quarterly》2013,33(1):29-36
Summary The course of post‐mortem breakdown of glycogen and ATP in turkey pectoralis major muscle was markedly influenced by several ante‐ and peri‐mortem variables. Application of a proper stunning procedure was highly effective in preventing peri‐ and post‐mortem muscle stress reactions. The physiological level of glycogen and ATP was not significantly affected by road transportation covering 260 km. Birds which rested for 24 hrs following transportation had lower glycogen and ATP levels at the moment of slaughter than non‐rested birds. According to the changes in the rate and extent of post‐mortem biochemical reactions, several meat characteristics such as water‐holding capacity, colour, and tenderness were significantly changed. Furthermore, the results also indicate that turkey breast muscle is susceptible to a PSE‐like condition as described in pork. 相似文献
1000.
Summary Since 1983 some pig breeding and fattening farms in the Netherlands have been faced with a considerable mortality in pigs due to Streptococcus suis type 2 infections. The most predominant clinical feature of S. suis type 2 infection is meningitis, although sudden deaths often occur. It was noted that some affected farms had imported breeding stock from the United Kingdom. Tonsils of slaughter pigs were collected from herds with and without a history of S. suis type 2 infections. Bacteriological examination was done by using an elective‐selective medium. No significant difference was found in carrier rates of S. suis type 2 between clinically healthy and affected herds (38% vs. 45%). A cohort study was carried out by regular bacteriological examination of tonsil biopsies on a farm with a high incidence of streptococcal meningitis. Twenty‐seven percent of the pigs were carriers of S. suis type 2 at nine weeks of age. Possible methods for disease control are discussed. 相似文献