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131.
Influence of maternal habitat choice,environment and spatial distribution of juveniles on their propensity for anadromy in a partially anadromous population of rainbow trout (Oncorhynchus mykiss) 下载免费PDF全文
Ana Laura Liberoff Analia Pamela Quiroga Carla Marcela Riva‐Rossi Jessica Adele Miller Miguel Alberto Pascual 《Ecology of Freshwater Fish》2015,24(3):424-434
This study evaluated the importance of the environment and spatial distribution of juvenile fish for the adoption of alternative migratory tactics in a partially anadromous population of rainbow trout (Oncorhynchus mykiss) from the Santa Cruz River. We captured young‐of‐the‐year fish along the river during autumn 2009, 2010 and spring 2010 and determined their maternal origin (anadromous vs. resident) using strontium to calcium ratios in the otolith core. Relative proportion of anadromous offspring, modelled with logistic regression, increased towards headwaters and in areas with deeper channels and larger substrate composition. Body length, modelled with linear multiple regression, varied positively with site depth, water velocity, substrate size and anadromous maternal origin. Based on evidence for limited juvenile movements (<25 km), the spatial extent of this study (240 Rkm) and the identification of large, contrasting reaches along the river, it is likely that the observed spatial distribution of juveniles and their association to sites with coarse substrate composition reflects maternal spawning activity. Results further indicate that anadromous females breed predominantly in middle and upper river sections in areas with coarse substrate. Given that body size in this system has been positively related to propensity for anadromy, we propose that female spawning choice affects their offspring's spatial distribution, providing the adequate physical template for anadromous offspring to reach or maintain larger body sizes and display anadromy themselves. Relevance of this study is also discussed in the context of alterations in response to future dam construction in one of the latest free‐flowing rivers sustaining anadromous O. mykiss. 相似文献
132.
Ravneet Behla Arvind H. Hirani Carla D. Zelmer Fengqun Yu W. G. Dilantha Fernando Peter McVetty Genyi Li 《Euphytica》2017,213(11):260
Sclerotinia stem rot (SR) is one of the most devastating diseases of canola/rapeseed. Quantitative trait loci (QTL) analyses were carried out to identify loci responsible for resistance to SR in three doubled haploid DH populations (H1, H2 and H3). Petiole inoculation technique PIT was used to evaluate the all populations for resistance to SR. Genetic maps were developed using sequence related amplified polymorphism SRAP and simple sequence repeat SSR markers. Genetic maps of the H1 and H2 populations were developed using 508 and 478 markers, respectively. Previously published genetic map of the H3 population was also used in this study. The QTL analysis was carried out for each replicate separately as well as on the average of all the replicates. The numbers of identified QTL in each analysis varied from four to six in the H1 population, three to six in the H2 population and two to six in the H3 population. A number of common QTL were identified between the replicates of each population. Two common QTL were identified on linkage group A7 and C6 between the H1 and H3 populations and one QTL on A9 between the H2 and H3 populations. We are the first to report, identification of common QTL between different populations of Brassica napus. 相似文献
133.
Natascia Magagnotti Carla Nati Gianni Picchi Raffaele Spinelli 《Agroforestry Systems》2011,82(1):77-86
The study compares two product strategies—chips versus firewood—and two technological levels—manual versus mechanized—as applied
to the thinning of walnut agroforestry plantations, established on ex-arable land. Such plantations are widespread all across
Europe, and their establishment was subsidized under the provisions of EU Directive 2080/90, and of regional grant schemes.
Field test data were used to build a simple deterministic model for estimating thinning productivity and cost under varying
work and economic conditions. This model can assist prospective users when checking the profitability of an operation, or
when assessing the competitiveness of alternative options. Removing nurse alder from young walnut plantations yields between
25 and 50 t of fresh biomass per hectare and is crucial to the good development of the stand. The study shows that the removal
of nurse alder from walnut plantations is economically viable, and it can also offer some profits if stand and market conditions
are favourable. As a rule, the average DBH of removal trees should not be smaller than 12 cm. Best results are obtained with
mechanized harvesting, which does not seem to cause heavier stand and soil damage than manual harvesting. Manual harvesting
is preferable only if the annual utilization of machinery is very low, and in this case it should be geared to firewood production.
The manual whole-tree harvesting (WTH) method used in this study offers the lowest performance under all conditions, and should
be replaced with some other manual alternative to WTH. Mechanized WTH offers a significant cost reduction over mechanized
short-wood (SWS) harvesting, but this difference is still rather limited: hence, other parameters come into play when deciding
what system to apply, and namely product price and mass output. In this respect, one also has to consider the cost of managing
the harvesting residue, and that of fertilizing, if soil nutrient depletion is to be feared. 相似文献
134.
The SPAD-502 and the FieldScout CM 1000 chlorophyll meters were compared in their performance in diagnosing the nutritional status of plants. Leaves of a wide range of greenness were used to push the sensitivity of the tools to their limits. Both devices showed high reproducibility when used by different operators. The SPAD-readings were well-correlated with leaf nitrogen (N) concentrations, since leaves from heavily fertilized plants were not included in the sample population. The FieldScout-readings showed a marked saturation curve with the leaf N concentration, thus it cannot be used as a reliable N nutritional status index. The results also showed that the use of SPAD-502 in the diagnosis of the nutritional status of an orchard requires the establishment of specific critical concentrations for cultivars and sampling dates. The SPAD-502 appeared to have potential in the diagnosis of the nutritional status of the orchard for nutrients other than N. 相似文献
135.
Vasilopulos RJ Mackin AJ Rickard LG Pharr GT Huston CL 《Journal of the American Animal Hospital Association》2006,42(6):424-429
The prevalence of cats shedding Giardia cysts (13.6%) in the present study was found to be higher than previously reported (1% to 11%) and may reflect a higher sensitivity for the diagnostic test used. The presence of Cryptosporidium spp. oocysts, coccidial oocysts, and a clinical history of chronic (>2 weeks) gastrointestinal signs were significantly associated with the presence of Giardia spp. cysts in the feces. There were no associations between the presence of Giardia spp. cysts and type of housing, acute gastrointestinal signs, vomiting, gender, source of cat (i.e., animal shelter versus private breeder), or gastrointestinal parasites other than Cryptosporidium spp. and intestinal coccidial agents. 相似文献
136.
Alexandre Alonso Alves Carla Cristina Gonçalves Rosado Danielle Assis Faria Lúcio Mauro da Silva Guimarães Douglas Lau Sérgio Hermínio Brommonschenkel Dario Grattapaglia Acelino Couto Alfenas 《Euphytica》2012,183(1):27-38
Eucalypts are susceptible to a wide range of diseases. One of the most important diseases that affect Eucalyptus plantations worldwide is caused by the rust fungus Puccinia psidii. Here, we provide evidence on the complex genetic control of rust resistance in Eucalyptus inter-specific hybrids, by analyzing a number of full-sib families that display different patterns of segregation for rust
resistance. These families are totally unrelated to those previously used in other inheritance studies of rust resistance.
By using a full genome scan with 114 genetic markers (microsatellites and expressed sequence tag derived microsatellites)
we also corroborated the existence and segregation of a resistance locus, explaining 11.5% of the phenotypic variation, on
linkage group 3, corresponding to Ppr1. This find represents an additional validation of this locus in totally unrelated pedigree. We have also detected significant
additive × additive digenic interactions with LOD >10.0 on several linkage groups. The additive and epistatic QTLs identified
explain between 29.8 and 44.8% of the phenotypic variability for rust resistance. The recognition that both additive and non-additive
genetic variation (epistasis) are important contributors to rust resistance in eucalypts reveals the complexity of this host-pathogen
interaction and helps explain the success that breeding has achieved by selecting rust-resistant clones, where all the additive
and non-additive effects are readily captured. The positioning of epistatic QTLs also provides starting points to look for
the underlying genes or genomic regions controlling this phenotype on the upcoming E. grandis genome sequence. 相似文献
137.
138.
Ale Analía Bacchetta Carla Rossi Andrea S. Scarabotti Pablo A. Cazenave Jimena 《Fish physiology and biochemistry》2021,47(4):829-839
Fish Physiology and Biochemistry - This study aimed to analyze the cold stress effects (in terms of hematology, energy reserves, and oxidative stress) in Piaractus mesopotamicus (pacú) and... 相似文献
139.
Francisca Samsing Megan Rigby Hedda K. Tengesdal Richard S. Taylor Daniela Farias Richard N. Morrison Scott Godwin Carla Giles Jeremy Carson Chloe J. English Roger Chong James W. Wynne 《Journal of fish diseases》2021,44(1):73-88
The Tasmanian salmon industry had remained relatively free of major viral diseases until the emergence of pilchard orthomyxovirus (POMV). Originally isolated from wild pilchards, POMV is of concern to the industry as it can cause high mortality in farmed salmon (Salmo salar). Field observations suggest the virus can spread from pen to pen and between farms, but evidence of passive transmission in sea water was unclear. Our aim was to establish whether direct contact between infected and naïve fish was required for transmission, and to examine viral infection dynamics. Atlantic salmon post‐smolts were challenged with POMV by either direct exposure via cohabitation or indirect exposure via virus‐contaminated sea water. POMV was transmissible in sea water and direct contact between fish was not required for infection. Head kidney and heart presented the highest viral loads in early stages of infection. POMV survivors presented low viral loads in most tissues, but these remained relatively high in gills. A consistent feature was the infiltration of viral‐infected melanomacrophages in different tissues, suggesting an important role of these in the immune response to POMV. Understanding POMV transmission and host–pathogen interactions is key for the development of improved surveillance tools, transmission models and ultimately for disease prevention. 相似文献
140.
Maia C Ramada J Cristóvão JM Gonçalves L Campino L 《Veterinary journal (London, England : 1997)》2009,179(1):142-144
Serology, bone marrow (BM)-, lymph node (LN)- and whole blood-polymerase chain reaction (PCR) were evaluated as potential reference tests for the diagnosis of canine leishmaniasis. A high degree of agreement (91.0%) was observed between Leishmania cultures and serology or BM/LN-PCR. In the light of these results as well as the access to biological test material and the cost of each method, LN-PCR is recommended for the diagnosis or therapeutic control of canine leishmaniasis, but BM-PCR is a suitable alternative in dogs without detectable adenomegaly. For large-scale epidemiological field studies, antibody detection is appropriate and whole blood-PCR can be used to complement the serological results. 相似文献