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排序方式: 共有243条查询结果,搜索用时 15 毫秒
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Novák J Tykva R Wimmer Z Pavlík M Prouza M Hlavsová K Zarevúcka M 《Journal of agricultural and food chemistry》2008,56(15):6604-6608
Two bacteria were isolated from sand RQ30, characterized as Bacillus simplex and Bacillus sp. strain 05 (GenBank EU399813 ), and were used as biocatalysts for a hydrolytic assay of stability of the cis or trans isomers of ethyl N-{2-{4-{[2-(butanoyl)oxycyclohexyl]methyl}phenoxy}ethyl}carbamate, which are among insect hormonogen substances (juvenogens). The stability tests were performed using simple modeling under laboratory conditions. The structures of the products were assigned as ethyl (1 R,2 R)- N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate and ethyl (1 S,2 R)- N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate on the basis of (1)H and (13)C NMR, IR, and FAB-MS analyses. 相似文献
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Stable isotopes and gut contents indicate differential resource use by coexisting asp (Leuciscus aspius) and pikeperch (Sander lucioperca) 下载免费PDF全文
Mojmír Vašek Antti P. Eloranta Ivana Vejříková Petr Blabolil Milan Říha Tomáš Jůza Marek Šmejkal Josef Matěna Jan Kubečka Jiří Peterka 《Ecology of Freshwater Fish》2018,27(4):1054-1065
Differential use of habitat and prey resources is an important mechanism that may allow coexistence of sympatric species. Unlike interactions between smaller cyprinid and percid fishes, the resource use by coexisting predatory asp (Leuciscus aspius) and pikeperch (Sander lucioperca) is relatively unknown. Here, gut content and stable isotope analyses were used to study ontogenetic dietary shifts and interspecific trophic niche overlap between asp and pikeperch coexisting in two reservoirs. The hypothesis that both species show an ontogenetic dietary shift from small invertebrates to large fish prey, but at the same time use different prey resources to reduce potential competitive interactions, was validated. The isotopic niches of the two predators showed no, or only a moderate, degree of overlap (0%–65%). The ontogenetic changes in the degree of interspecific isotopic niche overlap were different in the two reservoirs, suggesting that trophic segregation can be dynamic and variable among systems. Gut contents revealed that small (<100 mm standard length) asp consumed mostly terrestrial invertebrates and emerged aquatic insects, whereas small pikeperch foraged on zooplankton, larval and pupal stages of aquatic insects and fish. Larger individuals (>100 mm) of both species were predominantly piscivorous, with asp consuming more cyprinid prey and pikeperch more percid prey. Coexisting asp and pikeperch populations are able to utilise different prey resources, thereby reducing potential negative competitive interactions. 相似文献
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Knapczyk K Duda M Szafranska B Wolsza K Panasiewicz G Koziorowski M Slomczynska M 《Acta veterinaria Hungarica》2008,56(2):221-233
The sites of oestrogen action can be shown by the localisation of their receptors in the target tissues. The aim of the present study was to show the localisation of oestrogen receptors in porcine embryos and fetuses obtained on days 18, 22, 32, 40, 50, 60, 71 and 90 post coitum (p.c.). The visualisation of proteins was conducted in embryos and various fetal organs such as gonads, uterus, lung, kidney, intestine and adrenal gland. Both ERs were observed in the blastocysts on day 18 p.c. In the male, ERbeta was detected in the testis and epididymis, whereas ERalpha was present in the efferent ductules. In the female, ERbeta was detected in the ovarian stromal cells investing the oocyte nests, while ERalpha protein was detected in the surface epithelium. In the uterus, ERs were present in the stromal cells, while ERbeta was present in the luminal epithelium. In the non-reproductive fetal porcine tissues ERbeta was localised in the lungs, kidneys, adrenal glands and in the umbilical cords. Both ERs were observed in the intestine. It is possible that ERbeta may play important roles in the development of the adrenal gland, testis, kidney and lungs, while both ERs are involved in the development of the ovary, uterus, epididymis and intestine of the porcine fetus. 相似文献
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Rhythmic locomotor activity and daily susceptibility to deltamethrin were tested in the pine weevil,Hylobius abietis (L.) (Coleoptera, Curculionidae), a pest of young conifer plants. In constant darkness, beetles revealed a free-running circadian
pattern of locomotor activity (average period 22h : 20min). Under long photoperiod, L:D 18:6, entrainment of motor activity
was observed. In the entrained population of the weevils, a peak of locomotor activity occurred at about the beginning of
the dark phase, and the minimum occurred in the middle of the light phase. Fluctuations of susceptibility to a standard dose
of deltamethrin (0.5 μg/g body weight) varied across the day, and were inversely correlated to the changes in locomotor activity.
The importance of considering the daily organization of insect biology in studying insect resistance to pesticides is re-emphasized.
3 www.csa.com. The following databases were screened: Animal Behaviour Abstracts, AGRICOLA, Aquatic Science and Fishery Abstracts,
Biological Sciences, Ecology Abstracts, Entomology Abstracts, Environmental Science and Pollution Abstracts, Health and Safety
Science Abstracts, Pollution Abstracts, Water Resource Abstracts, Toxicology Abstracts, TOXLINE. 相似文献
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Sperm quality in male <Emphasis Type="Italic">Barbus barbus</Emphasis> L. fed different diets during the spawning season 总被引:1,自引:1,他引:0
Sayyed Mohammad Hadi Alavi Martin Pšenička Tomáš Policar Marek Rodina Jitka Hamáčková Pavel Kozák Otomar Linhart 《Fish physiology and biochemistry》2009,35(4):683-693
Sperm quality of Barbus barbus L. was compared among the three following dietary regimes: Group A, fed 100% commercial diet (Karpico™ containing 33% crude
protein and 6% fat), Group B, fed 78% commercial diet and 22% frozen chironomid (Chironomus plumosus) larvae, and Group C, fed 56% commercial diet and 44% frozen chironomid larvae. Concentrations of polyunsaturated fatty acids
(PUFAs) in Group A, B, and C were 39.1, 42.0, and 44.6, respectively, as a percentage of total fatty acids. Sperm morphology,
volume, concentration and motility, total number of spermatozoa, and osmolality of the seminal plasma were compared during
the spawning season. Dietary regime did not influence sperm volume, concentration, or total number of spermatozoa, osmolality
of seminal plasma, or the percentage of motile sperm, but significantly affected sperm morphology (except for anterior and
posterior parts of the midpiece) and sperm velocity (P < 0.05). Groups B and C showed similar sperm characteristics during the spawning season compared to Group A. Almost all parameters
changed either among or within groups during the spawning season, suggesting differences in terms of the optimal time for
sperm collection. The best time for sperm collection was March for Group A, but April for Groups B and C, when the osmolality
of the seminal plasma measured 289 mOsmol kg−1 and sperm motility was maximal. Spermatogenesis, hydration, and cell decomposition were confirmed as the three major parameters
controlling sperm characteristics during the spawning season. The possible correlation between sperm morphology and motility
requires further study. 相似文献