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71.
The concentration of vitamin R12 in the blood was studied in five totally gastrectomized pigs followed for 10–18 months, and in four controls followed for 5¼–8 months. The concentration of vitamin B12 in the liver was investigated in three pigs of each group. The content of vitamin B12 in the blood was of the same magnitude in both groups. Thus, removal of the stomach does not compromise the normal presence of this vitamin in the blood. The B12 content in the liver was also unaffected by the operation, whereas it was increased after simultaneous administration of vitamin B6.  相似文献   
72.
In this study, 221 two‐year‐old hatchery‐reared salmon, Salmo salar, smolts were tagged with radio transmitters over a period of three consecutive years and released in the river in groups of 20–21 fish in various dates between late April and early June. Tagged smolts were tracked during their downstream migration in the lower 36‐km stretch of the regulated River Oulujoki, with the focus on the effects of release date, water temperature and river flow on migration behaviour and survival. The results indicate that release timing and river temperature have profound effects on the initiation of migration, swimming speed and survival of released S. salar smolts. Smolts released early in the spring in cold waters ceased migration after brief downstream movement and were vulnerable to predation, whereas the migration speed and survival rates increased markedly for smolts released later in the spring.  相似文献   
73.
Trap fisheries can provide catches of high quality, and unwanted bycatch can be released with high survival. Light attraction could be an effective way of increasing trap catches, but research results are largely lacking. Experiments to test the effect of LED lights in trap-net fishing were conducted in two Finnish lakes where fishing targeted Eurasian perch Perca fluviatilis L. and roach Rutilus rutilus (L.). LED lights (white, green, red, blue and combinations) were attached inside the traps. The use of LED lights did not increase fish CPUE. Contrary to expectation, Eurasian perch catches were higher in traps without LED lights. Significant variation in CPUEs was observed, but without interaction with light treatments. The LED lights tested in this study do not increase the effectiveness of trap fishery targeting Eurasian perch and roach in Finnish lakes in the ice-free season.  相似文献   
74.
Migration behaviour, route selection and mortality of Atlantic salmon, Salmo salar L., smolts were studied at four different hydroelectric facilities in the River Mustionjoki, Finland, in May 2017. Radio-tagged smolts were released upstream of the power stations and tracked by stationary antenna-receiver systems and hand-held receivers. Tracking revealed a general tendency of smolts to move downstream with the main flow, but also variable behaviour and mortality related to diverse conditions characteristic of each power station. Average migration delay at the power stations ranged between 13.8 and 101.1 h (median: 1.7–61.5 h). Estimated mortality ranges were 0%–50% in the forebays, 4%–64% in the power stations and 2–30%/km during river migration after passage of the dam. This study provided essential information on behaviour and mortality in relation to local conditions at each power station required for successful application of fish bypass systems in a salmon restoration project.  相似文献   
75.
The effect of over‐expression in tobacco plants of cytosolic Cu,Zn‐superoxide dismutase (cytsod) and ascorbate peroxidase (cytapx) alone, or in combination, against bacterial wildfire and crown gall diseases, caused by Pseudomonas syringae pv. tabaci and Agrobacterium tumefaciens, respectively, was investigated. Disease tolerance was observed in all the transgenic lines against the two causal agents, with various levels of resistance, with the double transformants (lines 35 and 39) the most resistant against bacterial wild fire. In the case of P. syringae pv. tabaci, disease tolerance and symptom decrease was associated with a lower bacterial population and a higher level of several antioxidant defence enzymes. Transgenic lines also exhibited an enhanced tolerance against A. tumefaciens, with the transgenic line harbouring cytapx (line 51) the most resistant to crown gall disease. However, this was only observed with strain C58 among the three pathogenic strains tested. These results suggest that cytosolic antioxidant defences have a role in increasing tolerance to the oxidative stress caused by some bacterial pathogens, and resistance of these tobacco lines to wildfire disease seems to be independent of tissue necrosis.  相似文献   
76.
The oriented attachment of molecular clusters and nanoparticles in solution is now recognized as an important mechanism of crystal growth in many materials, yet the alignment process and attachment mechanism have not been established. We performed high-resolution transmission electron microscopy using a fluid cell to directly observe oriented attachment of iron oxyhydroxide nanoparticles. The particles undergo continuous rotation and interaction until they find a perfect lattice match. A sudden jump to contact then occurs over less than 1 nanometer, followed by lateral atom-by-atom addition initiated at the contact point. Interface elimination proceeds at a rate consistent with the curvature dependence of the Gibbs free energy. Measured translational and rotational accelerations show that strong, highly direction-specific interactions drive crystal growth via oriented attachment.  相似文献   
77.
Berries contain a large variety of different phenolic compounds such as anthocyanins, flavonols, tannins, and phenolic acids. Due to variation in the nature and content of the phenolic compounds, the antioxidant effect and other bioactivities of berry phenolics are strongly dependent on the berry raw material as the activities differ between the different phenolic constituents. In the present study, wild rowanberries ( Sorbus aucuparia ) and four cultivated sweet rowanberries, Burka, Granatnaja, Titan, and Zoltaja, were characterized for their phenolic composition and screened for antioxidant, antimicrobial, and antiadhesive activities. The HPLC and LC-MS analyses of phenolic composition revealed that the main phenolic constituents were caffeoylquinic acids, varying from 56 to 80% total phenolics. The cultivated species contained less caffeoylquinic acids and more anthocyanins (up to 28.5%). The phenolics derived from wild rowanberries were significantly effective at inhibiting lipid oxidation both in liposomes and in emulsions, especially when assessed by inhibition of the formation of hexanal (86-97% inhibition depending on concentration). The increase in anthocyanin content in the cultivated species did not result in significantly increased antioxidant activity. Both wild and cultivated rowanberry phenolics exhibited a bacteriostatic effect toward Staphylococcus aureus . In addition, the phenolic extract from Zoltaja was weakly inhibitory toward Salmonella sv. Typhimurium, whereas both Zoltaja- and Granatnaja-derived phenolics retarded Escherichia coli growth. The phenolic extracts of wild rowanberries and Burka showed an inhibitory effect on hemagglutination of E. coli HB101 (pRR7), which expresses the M hemagglutinin. It can be concluded that cultivation of rowanberries resulted in increased anthocyanin content, but this did not diminish their bioactivity in comparison to wild rowanberries rich in caffeoylquinic acids.  相似文献   
78.
关键内容 ①食品安全是西欧消费担心的主要问题,并且在世界各地得到越来越多的重视。  相似文献   
79.
We investigated the CO2] exploitation and genetic diversity inthree old and three new winter varieties of oilseed rape (Brassicanapus L.). Plants were cultivated in growth chambers with 360 ppmCO2 and 700 ppm CO2 under conditions simulating a normalgrowth season. Exposed to elevated CO2 the stomatal conductance(gs) and the maximum photosynthesis capacity (Amax) werereduced and the dry biomass and the total seed-number were increased.The response in seed-yield differed among the varieties; it was increased inthree varieties and decreased in three. The analysis of variance (ANOVA)showed that there were Treatment- and Week-effects on the gs, andthere were Variety-, Week- and Treatment-effects on the Amax. Itwas also evident that there were a Variety- and Variety-agegroup-effect onthe seed-yield, but the Variety-agegroup-effect could not explain theVariety-effect. When either or both covariates (seed-number andbiomass) were included in the model, the covariates themselves had asignificant effect and it became evident that there was a Treatment-effecton the seed-yield.From AFLP (amplified fragment length polymorphism) markers adendrogram was constructed by the UPGMA method (unweightedpair-group method using the arithmetic averages) and [G ST wascalculated for all possible subsets of the varieties. The three old varietiescomprised the densest cluster and were also more genetically diverse thantwo of the three new varieties. Varieties with clear changes amongCO2 levels were rather genetically diverse.Thus, the varieties represent different traits, which could be exploited infuture breeding of oilseed rape.  相似文献   
80.
Summary Interspecific F1-hybrids may arise in fields with transplastomic oilseed rape where B. rapa occurs as a weed. Spilled seeds, including transplastomic F1-hybrids with B. rapa, may germinate, which creates an opportunity for production of transplastomic BC1 with B. rapa as father (BC1r). Field trials were made with three different proportions of B. napus, B. rapa and F1-hybrids and three different densities. Contrary to most studies on how plant competition affects introgression between oilseed rape and B. rapa, this study focused on offspring produced on F1-hybrids, where the F1-hybrids had oilseed rape as maternal parent. We estimated the BC1r production in all combinations of proportion and density, and found that B. rapa sired from 0.6–7.8% of the offspring. At the proportion with the highest abundance of F1-hybrids the entire paternity was assessed. There was a significant density effect on the production of BC1r but the effect differed among proportions. Both the highest and lowest frequencies of BC1r were obtained at high plant density. Neither the proportion nor density affected the number of BC1r per square-meter significantly. Biomass components decreased significantly from low to intermediate density, whereas a further increase in density only affected the thousand-seed weight significantly. On the basis of the results from the present experiment we conclude that introgression of transgenes from transplastomic oilseed rape to B. rapa seems most likely at current field densities of B. napus, and when B. rapa is an abundant weed.  相似文献   
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