全文获取类型
收费全文 | 316篇 |
免费 | 29篇 |
专业分类
林业 | 11篇 |
农学 | 6篇 |
112篇 | |
综合类 | 12篇 |
农作物 | 14篇 |
水产渔业 | 23篇 |
畜牧兽医 | 129篇 |
园艺 | 6篇 |
植物保护 | 32篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 15篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 20篇 |
2015年 | 9篇 |
2014年 | 17篇 |
2013年 | 21篇 |
2012年 | 25篇 |
2011年 | 24篇 |
2010年 | 7篇 |
2009年 | 10篇 |
2008年 | 23篇 |
2007年 | 18篇 |
2006年 | 20篇 |
2005年 | 3篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 7篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1989年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1954年 | 1篇 |
1949年 | 1篇 |
排序方式: 共有345条查询结果,搜索用时 31 毫秒
261.
Early perception of stink bug damage in developing seeds of field‐grown soybean induces chemical defences and reduces bug attack
下载免费PDF全文
![点击此处可从《Pest management science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
262.
263.
264.
Alessandra Fondati Michela De Lucia Nicla Furiani Moira Monaco Laura Ordeix Fabia Scarampella 《Veterinary dermatology》2010,21(2):146-151
Demodex canis is thought to be present in small numbers in the skin of most healthy dogs; however, available data on the prevalence of normal dogs harbouring D. canis are scarce. The purpose of this study was to investigate, using microscopic examination of plucked hairs, the prevalence of healthy dogs harbouring D. canis. Seventy‐eight clinically healthy dogs with no history of dermatological problems and clinically normal skin and hair coat were included in the study. Five areas (perioral skin 2–3mm from both labial commissures, periungual skin of the third digit of both anterior paws and chin) were examined in each dog. Fifty to sixty hairs were plucked from each skin site and microscopically examined. No D. canis mites were observed and only one adult form of Demodex injai was found in the labial commissure of one dog. Based on these results, the estimated prevalence of healthy dogs harbouring D. canis in clinically normal skin should not exceed the threshold of 5.4%, with 95% confidence level. Considering our and previous findings, we propose that, although small numbers of D. canis might inhabit the skin of normal dogs, the probability of finding these mites in normal dogs is low. Consequently, in most cases, the presence of a D. canis mite in the skin should not be considered as indicative of normality. 相似文献
265.
266.
Dragano NR de Venancio VP Paula FB Della Lucia F Fonseca MJ Azevedo L 《Plant foods for human nutrition (Dordrecht, Netherlands)》2010,65(4):319-325
Brazilian savanna constitutes a valuable ecoregion that contributes to the supply of fruit known worldwide for its nutritional
value and peculiar flavors. Among them, the Marolo (Annona crassiflora Mart.) fruit is known for its use in folk medicine. In order to establish the safety of Marolo for human consumption, this
study evaluated the following: the chemical composition of Marolo pulp; its mutagenic and antimutagenic activities using micronucleus
test; and the oxidative stress induced in the livers of mice fed a diet containing 1%, 10% or 20% pulp. It was observed that
the chemical composition of marolo pulp was similar to that of common fruit; nevertheless, its lipidic content and energetic
values were higher. In the mice fed experimental diets, the biochemical parameters of the blood serum showed normal levels
of glucose, triglycerides, and cholesterol. The micronucleus test indicated neither mutagenic nor antimutagenic effects of
Marolo consumption on bone marrow cells but showed potentialization of cyclophosphamide (CP). The oxidative stress levels
observed indicated that CP was not exerting a great influence on the induction of reactive oxygen species. As the whole fruit
is a complex matrix, the interactions between its components could be responsible for its negative and positive biological
effects. 相似文献
267.
Gabriel Soares Campos Fernando Flores Cardoso Claudia Cristina Gulias Gomes Robert Domingues Luciana Correia de Almeida Regitano Marcia Cristina de Sena Oliveira Henrique Nunes de Oliveira Roberto Carvalheiro Lucia Galvo Albuquerque Stephen Miller Ignacy Misztal Daniela Lourenco 《Journal of animal science》2022,100(2)
Genomic prediction has become the new standard for genetic improvement programs, and currently, there is a desire to implement this technology for the evaluation of Angus cattle in Brazil. Thus, the main objective of this study was to assess the feasibility of evaluating young Brazilian Angus (BA) bulls and heifers for 12 routinely recorded traits using single-step genomic BLUP (ssGBLUP) with and without genotypes from American Angus (AA) sires. The second objective was to obtain estimates of effective population size (Ne) and linkage disequilibrium (LD) in the Brazilian Angus population. The dataset contained phenotypic information for up to 277,661 animals belonging to the Promebo breeding program, pedigree for 362,900, of which 1,386 were genotyped for 50k, 77k, and 150k single nucleotide polymorphism (SNP) panels. After imputation and quality control, 61,666 SNPs were available for the analyses. In addition, genotypes from 332 American Angus (AA) sires widely used in Brazil were retrieved from the AA Association database to be used for genomic predictions. Bivariate animal models were used to estimate variance components, traditional EBV, and genomic EBV (GEBV). Validation was carried out with the linear regression method (LR) using young-genotyped animals born between 2013 and 2015 without phenotypes in the reduced dataset and with records in the complete dataset. Validation animals were further split into progeny of BA and AA sires to evaluate if their progenies would benefit by including genotypes from AA sires. The Ne was 254 based on pedigree and 197 based on LD, and the average LD (±SD) and distance between adjacent single nucleotide polymorphisms (SNPs) across all chromosomes were 0.27 (±0.27) and 40743.68 bp, respectively. Prediction accuracies with ssGBLUP outperformed BLUP for all traits, improving accuracies by, on average, 16% for BA young bulls and heifers. The GEBV prediction accuracies ranged from 0.37 (total maternal for weaning weight and tick count) to 0.54 (yearling precocity) across all traits, and dispersion (LR coefficients) fluctuated between 0.92 and 1.06. Inclusion of genotyped sires from the AA improved GEBV accuracies by 2%, on average, compared to using only the BA reference population. Our study indicated that genomic information could help us to improve GEBV accuracies and hence genetic progress in the Brazilian Angus population. The inclusion of genotypes from American Angus sires heavily used in Brazil just marginally increased the GEBV accuracies for selection candidates. 相似文献
268.
Lenucci MS Serrone L De Caroli M Fraser PD Bramley PM Piro G Dalessandro G 《Journal of agricultural and food chemistry》2012,60(7):1764-1775
This study reports quali-quantitative analyses on isoprenoids, phospholipids, neutral lipids, phytosterols, and proteins in purified plastids isolated from fresh fruits of traditional (Donald and Incas) and high-pigment (Kalvert and HLY-18) tomato cultivars at four ripening stages. In all of the investigated cultivars, lycopene, β-catotene, lutein, and total carotenoids varied significantly during ripening. Chromoplasts of red-ripe tomato fruits of high-pigment cultivars accumulated twice as much as lycopene (307.6 and 319.2 μg/mg of plastid proteins in Kalvert and HLY-18, respectively) than ordinary cultivars (178.6 and 151.7 μg/mg of plastid proteins in Donald and Incas, respectively); differences in chlorophyll and α-tocopherol contents were also evidenced. Phospholipids and phytosterols increased during ripening, whereas triglycerides showed a general decrease. Regardless of the stage of ripening, palmitic acid was the major fatty acid in all cultivars (ranging from 35 to 52% of the total fatty acids), followed by stearic, oleic, linoleic, linolenic, and myristic acids, but their relative percentage was affected by ripening. Most of the bands detected on the SDS-PAGEs of plastid proteins were constantly present during chloroplast-to-chromoplast conversion, some others disappeared, and only one, with a molecular weight of ~41.6 kDa, was found to increase in intensity. 相似文献
269.
The effect of an enhanced (5%) sub-lethal UVA irradiation on the total metabolism of a sub- tropical convict cichlid (Cichlasoma nigrofasciatum) is described. The specific oxygen consumption (vo2) of related but differently treated populations was determined from 23 °C to 35 °C, to detect their tolerance limits toward environmental temperature. The experiments cover two generations (G1 and G2) of inbred derived populations. The fish were measured at different stages of development covering the period before and after maturation. The fish were grown at and adapted to 27–29 °C. The results showed that the population which was grown under an enhanced UVA irradiation since hatching (G2-UVA) had developed a general metabolic depression (MD) at all ranges of experimental temperature. The MD was especially expressed after the fish reached maturation. No MD was shown for the non-irradiated control populations (G2-control and G1-control) nor for the mature fish of G1-UVA. The G1-UVA population was grown under an enhanced UVA irradiation from 4 months of age. The vo2 increased with increasing temperature, reaching a maximum at 31–33 °C for the G1- and G2-control populations. For the G1-UVA, a small peak of vo2 was obtained at 29 °C reaching its maximum level at 33 °C. For the G2-UVA population, a maximum vo2 was reached at 33 °C for the young and mature fish and at 29 °C during the maturation period. It can be concluded that the accumulation of UVA irradiation from early life was responsible for the MD in this fish. A wider temperature tolerance observed in the G2-UVA population might possibly be due to a reduction of total metabolic activity. The mechanisms underlying the MD observed in this fish are not yet known, but natural selection and adaptation processes might be involved. 相似文献
270.
The occurrence of intermixing, especially that resulting from genetically modified (GM) species, is increasingly becoming a problem in the delicate chain of feed and food quality control. Thus, a strategy is needed for precisely quantifying the presence of intermixing. An analytical assay based on real-time PCR has been developed; it can ascertain the extent of unexpected intermixing of GM soybean with maize meal. Three soybean-maize mix levels, with soybean intermix percentages of, respectively, 0.1, 0.5, and 1%, were prepared to simulate samples containing traces of soybean. As calibrator standards, ad hoc multiple-target pGEM-T plasmids containing soybean and maize reference genes in a 1:1 ratio were constructed. Four different maize endogenous genes, alcohol dehydrogenase 1 (adh1), high-mobility group protein a (hmga), invertase 1 (ivr1), and zein (zein), were assessed, each combined with the soybean endogenous lectin 1 (lect1) gene. Plasmids containing adh1-lect1 and zein-lect1 genes were found to be the most reliable calibration systems for this analysis, providing precise and accurate quantification results. Measuring the percentage of GM soybean intermixing makes it possible to calculate the actual transgenic component of the total sample. 相似文献