全文获取类型
| 收费全文 | 82篇 |
| 免费 | 6篇 |
专业分类
| 林业 | 15篇 |
| 农学 | 5篇 |
| 基础科学 | 1篇 |
| 27篇 | |
| 综合类 | 2篇 |
| 农作物 | 5篇 |
| 水产渔业 | 6篇 |
| 畜牧兽医 | 23篇 |
| 园艺 | 3篇 |
| 植物保护 | 1篇 |
出版年
| 2024年 | 1篇 |
| 2022年 | 2篇 |
| 2021年 | 4篇 |
| 2020年 | 1篇 |
| 2019年 | 1篇 |
| 2018年 | 4篇 |
| 2017年 | 4篇 |
| 2016年 | 10篇 |
| 2015年 | 5篇 |
| 2014年 | 4篇 |
| 2013年 | 6篇 |
| 2012年 | 7篇 |
| 2011年 | 6篇 |
| 2010年 | 3篇 |
| 2009年 | 2篇 |
| 2008年 | 6篇 |
| 2007年 | 4篇 |
| 2006年 | 2篇 |
| 2005年 | 2篇 |
| 2004年 | 2篇 |
| 2003年 | 5篇 |
| 2002年 | 2篇 |
| 2001年 | 1篇 |
| 1999年 | 1篇 |
| 1996年 | 1篇 |
| 1990年 | 1篇 |
| 1985年 | 1篇 |
排序方式： 共有88条查询结果，搜索用时 31 毫秒
61.
62.
J. Sánchez Espańa E. López Pamo E. Santofimia Pastor J. Reyes AndrÉs J. A. MartÍn RubÍ 《Water, air, and soil pollution》2006,173(1-4):121-149
The Odiel river emerges in Sierra de Aracena (N Huelva, Spain) as a clean, circumneutral river which shows abundant fish and fluvial microfauna. At 20km from the riverhead and along a 7km-long reach, this river receives four small discharges of acid mine water emanating from several abandoned mines of the Iberian Pyrite Belt (namely, Concepción, San Platón, Esperanza and La Poderosa-El Soldado). During two field studies performed in October 2003 and May 2004, it has been observed that these acidic waters (with flow rate of 0.2–8.5L/s and pH 2.3–2.8) transfer to the Odiel river significant amounts of acidity and dissolved metals (specially Fe, Al, Mn, Cu, Zn, Cd, Co and Ni) and sulphate. Despite this mine-related pollution, the pH of the river remains near-neutral (pH = 7–8, flow rate = 220–1,000L/s), as the alkalinity of the river (108–155mg/L CaCO3 eq.) neutralizes the acidity and causes the precipitation of dissolved Fe and Al in the form of ochreous to whitish minerals (ferrihydrite, Al-oxyhydroxides). These poorly crystallized minerals retain, by sorption, large amounts of trace metals (specially Cu and Zn). Subsequently, the Odiel river converges with the acidic Tintillo river (pH = 2.5–2.8, flow rate = 48–240L/s), which drains a vast mining area occupied by large waste-rock piles and tailings impoundments around Corta Atalaya (Riotinto mines). At this confluence, all the alkalinity is totally consumed and the pH drastically decreases to around 3. The mineral paragenesis of the ochreous precipitates is then dominated by schwertmannite, which shows a very limited sorption capacity under such acidic conditions. Consequently, metal concentrations are sharply increased from near-zero to tens of mg/L (e.g., 18mg/L Fe, 76mg/L Al, 14mg/L Mn, 10mg/L Cu, and 20mg/L Zn in May 2004). The buffering capacity of the Fe(III) hydrolysis stabilizes the pH of the Odiel river around 3± 0.5 along the rest of its course to the Huelva estuary, and the water quality of the river is thus irreversibly damaged. 相似文献
63.
Rubén N González David J Wilson 《Veterinary Clinics of North America: Food Animal Practice》2003,19(1):199-221
Mycoplasmal bovine mastitis is potentially a highly contagious disease that can cause severe economic problems in affected herds. The purchase of replacement heifers and cows are frequently the origin of mycoplasmal mastitis outbreaks in previously Mycoplasma-free herds. Purchased cows and heifers should be quarantined and tested for mycoplasmal mastitis before admission to the regular herd. Detection of Mycoplasma-infected cows by culture of milk is straightforward, although there are problems of sensitivity for its detection in milk samples that are inherent to the nature of the disease and laboratory procedures. After detection of infected cows, the best way to protect the herd is to culture all cows in the herd, cows with clinical mastitis, and all heifers and cows after calving and before entering the milking herd. Control of mycoplasmal mastitis requires test and culling from the herd of Mycoplasma-positive cows if possible. When a large number of cows are infected, strict segregation with adequate management is an option; however, animals in this group should never re-enter the Mycoplama-free herd. The functioning of the milking equipment and milking procedures should be evaluated carefully and any flaws corrected. There is no treatment for mycoplasmal mastitis, and vaccination has not proven to be efficacious to prevent, decrease the incidence, or ameliorate the clinical signs of mycoplasmal mastitis. Waste milk should not be fed to calves without pasteurization. M bovis may cause several other pathologies in animals of different ages on a farm, including pneumonia, arthritis, and ear infections. The survival of mycoplasmas in different farm microenvironments needs to be further investigated for its impact on the epidemiology of the disease. 相似文献
64.
Ecotoxicological assessment of the effects of glyphosate and chlorpyrifos in an Argentine soya field 总被引：2，自引：0，他引：2
Norma Casabé Lucas Piola Julio Fuchs María Luisa Oneto Laura Pamparato Silvana Basack Rosana Giménez Rubén Massaro Juan C. Papa Eva Kesten 《Journal of Soils and Sediments》2007,7(4):232-239
Background, Aim and Scope
Continuous application of pesticides may pollute soils and affect non-target organisms. Soil is a complex ecosystem; its components can modulate the effects of pesticides. Therefore, it is recommended to evaluate the potential environmental risk of these compounds in local conditions. We performed an integrated field-laboratory study on an Argentine soya field sprayed with glyphosate and chlorpyrifos under controlled conditions. Our aim was to compare the sensitivity of a series of endpoints for the assessment of adverse effects of the extensive use of these agrochemicals.Materials and Methods
A RR soya field in a traditional farming area of Argentina was sprayed with glyphosate (GLY) or chlorpyrifos (CPF) formulations at the commercially recommended rates, according to a randomized complete block design with 3 replicates. In laboratory assays, Eisenia fetida andrei were exposed to soil samples (0–10 cm depth) collected between the rows of soya. Endpoints linked to behavior and biological activity (reproduction, avoidance behavior and bait-lamina tests) and cellular/subcellular assays (Neutral Red Retention Time — NRRT; DNA damage — Comet assay) were tested. Field assays included litterbag and bait-lamina tests. Physico/chemical analyses were performed on soil samples.Results
GLY reduced cocoon viability, decreasing the number of juveniles. Moreover, earthworms avoided soils treated with GLY. No effects on either reproduction or on avoidance were observed at the very low CPF concentration measured in the soils sampled 10 days after treatment. Both pesticides caused a reduction in the feeding activity under laboratory and field conditions. NRRT was responsive to formulations of CPF and GLY. Comet assay showed significantly increased DNA damage in earthworms exposed to CPF treated soils. No significant differences in DNA migration were observed with GLY treated soils. Litterbag field assay showed no differences between treated and control plots.Discussion
The ecotoxicological effects of pesticides can be assessed by monitoring the status of communities in real ecosystems or through the use of laboratory toxicity tests. Litterbag field test showed no influence of the treatments on the organic matter breakdown, suggesting a scarce contribution of soil macrofauna. The bait-lamina test, however, seemed to be useful for detecting the effects of GLY and CPF treatments on the activity of the soil fauna. CPF failed to give significant differences with the controls in the reproduction test and the results were not conclusive in the avoidance test. Although the field population density of earthworms could be affected by multiple factors, the effects observed on the reproduction and avoidance tests caused by GLY could contribute to its decrease, with the subsequent loss of their beneficial functions. Biomarkers measuring effects on suborganism level could be useful to predict adverse effects on soil organisms and populations. Among them, NRRT, a lysosomal destabilization biomarker, resulted in demonstrating more sensitivity than the reproduction and avoidance tests. The Comet assay was responsive only to CPF. Since DNA damage can have severe consequences on populations, it could be regarded as an important indicator to be used in the assessment of soil health.Conclusions
Reproduction and avoidance tests were sensitive indicators of GLY exposure, with the former being more labor intensive. Bait-lamina test was sensitive to both CPF and GLY. NRRT and Comet assays revealed alterations at a subcellular level, and could be considered complementary to the biological activity tests. Because of their simplicity, some of these bioassays seemed to be appropriate pre-screening tests, prior to more extensive and invasive testing.Recommendations and Perspectives
This study showed deleterious effects of GLY and CPF formulations when applied at the nominal concentrations recommended for soya crops. Further validation is needed before these endpoints could be used as field monitoring tools in Argentine soya soils (ecotoxicological risk assessment — ERA tools).65.
Luciana Camacho-Pérez Jaime Martínez-Castillo Javier O. Mijangos-Cortés Miriam M. Ferrer-Ortega Jean Pierre Baudoin Rubén H. Andueza-Noh 《Genetic Resources and Crop Evolution》2018,65(1):229-241
Lima bean (Phaseolus lunatus L.) is an important crop in the Mayan culture. The Mayan area, considered as a main center of Mesoamerican diversity, has been divided into two subareas: the Mayan lowlands and the Mayan highlands. The Yucatan Peninsula is part of the Mayan lowlands and holds the highest number of Lima bean landraces of Mexico, but Lima beans are in high risk of genetic erosion due to intensification of the traditional Mayan agriculture. However, information on genetic diversity of Lima beans of the Mayan highlands is lacking. By using 46 landraces collected in the Mayan area (23 from each subarea) and 73 ISSR loci (inter-simple sequence repeats), we analyzed the structure, diversity and genetic relationships of Lima beans of this part of Mesoamerica. High levels of diversity (H BAY = 0.45) and genetic structure (F ST = 0.66) were found for the whole Mayan area. Genetic diversity in the Mayan lowlands was apparently higher than the Mayan highlands (H BAY = 0.44 and 0.36, respectively); but differences were not statistically significant. Genetic structure between the subareas was high (AMOVA = 30% of total variation), most landraces grouping according to their geographic origin. This study shows the importance of the Mayan culture in the diversification and conservation of Lima beans. The results provide important information that should be considered when implementing strategies to collect Lima bean landraces and planning in situ and ex situ programs to conserve these landraces in the Mayan region. 相似文献
66.
Pablo F. Roncallo Gerardo L. Cervigni Carlos Jensen Rubén Miranda Alicia D. Carrera Marcelo Helguera Viviana Echenique 《Euphytica》2012,185(1):77-92
The aim of this work was to map quantitative trait loci (QTLs) associated with flour yellow color (Fb*) and yellow pigment
content (YPC) in durum wheat (Triticum turgidum L. var. durum). Additionally, QTLs affecting flour redness (Fa*) and brightness (FL*) color parameters were investigated. A population
of 93 RILs (UC1113 × Kofa) was evaluated in three locations of Argentina over 2 years. High heritability values (>94%) were
obtained for Fb* and YPC, whereas FL* and Fa* showed intermediate to high values. The main QTLs affecting Fb* and YPC overlapped
on chromosome arms 4AL (4AL.2), 6AL (6AL.2), 7AS, 7AL, 7BS (7BS.2) and 7BL (7BL.2). The 7BL.1 QTL included the Psy-B1 locus, but one additional linked QTL was detected. A novel minor QTL located on 7AS affected Fb*, with an epistatic effect
on YPC. An epistatic interaction occurred between the 7AL and 7BL.2 QTLs. The 4AL.2 QTL showed a strong effect on Fb* and
was involved in two digenic epistatic interactions. The 6AL.2 QTL explained most of the variation for Fb* and YPC. The main
QTLs affecting FL* and Fa* were located on 2BS and 7BL, respectively. These results confirm the complex inheritance of flour
color traits and open the possibility of developing perfect markers to improve pasta quality in Argentinean breeding programs. 相似文献
67.
We present observations on an unusual tetratrichomonad species isolated from preputial smegma of virgin bulls. Ultrastructural studies were performed using scanning and electron microscopy techniques. This protozoan presents four anterior flagella of unequal length and a recurrent one forming the undulating membrane. It shows one anterior nucleus, a Golgi complex, an axostyle, and a costa. The hydrogenosomes are rather elongated, seen in groups, and presenting different electron densities. Vacuoles of different sizes containing bacteria and material in process of digestion were frequently found. PCR was also used in order to compare the species herein described with other trichomonad species. The amplification products were seen only with primers TFR1 and TFR2 (specific to trichomonads), but not with TFR3 and TFR4 (specific to Tritrichomonas foetus), suggesting that although collected from the genital tract of the bull, this protist was not T. foetus. We propose that the appearance of these tetratrichomonads were probably due to the sodomy practiced among bulls. Concomitant contamination of preputial cavity with feces could explain the presence of the opportunistic organism. The observations presented here show the importance of the correct diagnostic when investigating samples obtained from the urogenital tract of cattle. We also suggest that this flagellate belongs to the species Tetratrichomonas buttreyi. 相似文献
68.
David J Wilson Rubén N González 《Veterinary Clinics of North America: Food Animal Practice》2003,19(1):187-97, vii-viii
Brief history and extensive published field efficacy data of the two rough ("R") bacterial mutants utilized in commercial preparations of the core antigen bacterins Escherichia coli O111:B4 (strain J5) and Salmonella typhimurium Re-17 are summarized. Particular dosage schedules and routes of administration of coliform mastitis bacterins are compared for their associated ecacy. Practical concerns in employing a coliform mastitis vaccination program are discussed. Characteristics of farms using coliform mastitis vaccination and suggested guidelines for whether individual dairy herds should adopt this practice are presented for consideration. 相似文献
69.
Effect of humic acids on intestinal viscosity,leaky gut and ammonia excretion in a 24 hr feed restriction model to induce intestinal permeability in broiler chickens 
下载免费PDF全文
下载免费PDF全文 Jesús A. Maguey‐Gonzalez Matias A. Michel Mikayla F.A. Baxter Guillermo Tellez Jr. Philip A. Moore Jr. Bruno Solis‐Cruz Daniel Hernández‐Patlan Rubén Merino‐Guzman Xochitl Hernandez‐Velasco Juan D. Latorre Billy M. Hargis Sergio Gomez‐Rosales Guillermo Tellez‐Isaias 《Animal Science Journal》2018,89(7):1002-1010
The purpose of this study was to evaluate the effect of humic acids (HA) on intestinal viscosity, leaky gut and ammonia excretion in a 24 hr feed restriction (FR) model to induce intestinal permeability in chickens. One‐day‐old male Cobb‐Vantress broilers were randomly allocated to one of two groups (n = 25 chickens), with or without 0.2% of isolated HA from worm‐compost, and placed in brooder batteries. Chicks had ad libitum access to water and feed for 14 days. Intestinal permeability was induced by 24 hr FR starting at 14 days. At 15 days of age, chickens in both groups were given an appropriate dose of fluorescein isothiocyanate dextran (FITC‐d) by oral gavage. Intestine and liver samples were also collected to evaluate viscosity and bacterial translocation (BT), respectively. An increase (p < .05) in intestinal viscosity was observed in the experimental group consuming 0.2% of HA and was confirmed in a published in vitro digestion model that simulates the chemical and physical conditions of the crop, proventriculus and intestine of chickens. Furthermore, the treated group also showed a significant reduction in FITC‐d, liver BT and ammonia in the manure. These results suggest that HA have a positive impact in intestinal integrity in chickens. 相似文献
70.