全文获取类型
收费全文 | 101篇 |
免费 | 8篇 |
专业分类
林业 | 14篇 |
农学 | 4篇 |
19篇 | |
综合类 | 7篇 |
农作物 | 6篇 |
水产渔业 | 10篇 |
畜牧兽医 | 42篇 |
园艺 | 3篇 |
植物保护 | 4篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 8篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 3篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1991年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有109条查询结果,搜索用时 19 毫秒
1.
Alessandro Vastolo Serena Calabrò Severina Pacifico Bossima Ivan Koura Monica Isabella Cutrignelli 《Journal of animal physiology and animal nutrition》2021,105(Z1):1-9
Cannabis sativa L. is an annual herbaceous plant. It was used for centuries to obtain different products. In the last century, hemp cultivation was forbidden due to the psychoactive effects of tetrahydrocannabinol acid (THCA). In the last years, new strains, characterized by high cannabidiolic acid (CBDA) and low THCA level, were developed renewing the interest in hemp cultivation to obtain food or to extract essential oils from flowers. All these processes produce many residues with different chemical–physical characteristics. In order to evaluate their potential use also in animal nutrition, some hemp co-products were evaluated. Two different co-products of seed processes (flour and oil) and two co-products obtained trimming the flowers, differing in granulometry were used. The samples were analysed for chemical composition and evaluated in vitro using the gas production technique with buffaloes' ruminal inoculum. All hemp co-products showed interesting nutritional characteristics, such as crude protein content always higher than 20% on a dry matter basis, and high neutral detergent fibre concentration partially lignified. The in vitro gas production parameters at 120 h of incubation showed quite low fermentability testified by the low organic matter degradability and cumulative gas volume (OMD from 28.09 to 45.64% and OMCV from 110 to 164 ml/g, respectively). Also, the methane produced after 24 h of incubation was particularly low (from 1.78 to 11.73 ml/g dOM). These results could be due to the high lipid and ash amounts or to the CBDA content that probably affected the CH4 formation processes. According to preliminary results obtained by this study, it is possible to hypothesize that these co-products could be useful to mitigate the methane production into the rumen. Further studies are necessary in order to evaluate the correct inclusion into the diet for ruminants. 相似文献
2.
INTER‐ AND INTRAFRACTION MOTION FOR STEREOTACTIC RADIOSURGERY IN DOGS AND CATS USING A MODIFIED BRAINLAB FRAMELESS STEREOTACTIC MASK SYSTEM 下载免费PDF全文
Sonja Dieterich Allison Zwingenberger Katherine Hansen Isabella Pfeiffer Alain Théon Michael S. Kent 《Veterinary radiology & ultrasound》2015,56(5):563-569
Precise and accurate patient positioning is necessary when doing stereotactic radiosurgery (SRS) to ensure adequate dosing to the tumor and sparing of normal tissues. This prospective cross‐sectional study aimed to assess feasibility of a commercially available modified frameless SRS positioning system for use in veterinary radiotherapy patients with brain tumors. Fifty‐one dogs and 12 cats were enrolled. Baseline and verification CT images were acquired. The verification CT images from 32 dogs and five cats had sufficient images for fusion to baseline CT images. A rigid box‐based fusion was performed to determine interfraction motion. Forty‐eight dogs and 11 cats were assessed for intrafraction motion by cine CT. Seventy percent of dogs and 60% of cats had interfraction 3D vector translational shifts >1 mm, with mean values of 1.9 mm in dogs, and 1.8 mm in cats. In dogs muscle wasting was weakly correlated with translational shifts. The maximum angular interfraction motion observed was 6.3° (roll), 3.5° (pitch), and 3.3° (yaw). There was no correlation between angular interfraction motion and weight, brachycephaly, or muscle wasting. Fifty‐seven percent of dogs and 50% of cats had respiration‐related intrafraction motion. Of these, 4.5% of dogs and 10% of cats had intrafraction motion >1 mm. This study demonstrates the modified Brainlab system is feasible for SRS in dogs and cats. The smaller cranial size and difference in anatomy increases setup uncertainty in some animals beyond limits usually accepted in SRS. Image‐guided positioning is recommended to achieve clinically acceptable setup accuracy (<1 mm) for SRS. 相似文献
3.
PE Sbardella RR Ulguim DL Fontana CV Ferrari ML Bernardi I Wentz FP Bortolozzo 《Reproduction in domestic animals》2014,49(1):59-64
The study evaluated the reproductive performance of primiparous sows submitted to post‐cervical insemination (PCAI) compared with cervical artificial insemination (CAI). Difficulty with catheter introduction, the occurrence of bleeding or semen backflow during insemination, and volume and sperm cell backflow up to 60 min after insemination were also evaluated. Sows were homogenously distributed, according to body weight loss in lactation, lactation length, weaned piglets, weaning‐to‐oestrus interval and total born in previous farrowing, in two treatments: PCAI (n = 165) with 1.5 × 109 sperm cells in 45 ml (2.4 ± 0.04 doses per sow) and CAI (n = 165) with 3 × 109 sperm cells in 90 ml (2.5 ± 0.04 doses per sow). During PCAI, sows were inseminated in the absence of boars. Transabdominal real‐time ultrasonography was performed at oestrus onset, immediately before the first insemination and at 24 h after last insemination. There was no difference (P > 0.05) between treatments in farrowing rate (91.5% × 89.1%) and litter size (12.5 × 11.9 piglets born, respectively for PCAI and CAI sows). Successful passage of the intrauterine catheter in all the inseminations was possible in 86.8% (165/190) of sows initially allocated to PCAI treatment. Difficulty of introducing the catheter in at least one insemination did not affect the reproductive performance of PCAI sows (P > 0.05). Bleeding during insemination did not affect (P > 0.05) the farrowing rate in both treatments, but litter size was reduced in CAI and PCAI sows (P ≤ 0.06). Percentage of spermatozoa present in backflow within 1 h after insemination was greater in CAI than PCAI sows (P < 0.01). More than 85% of primiparous sows can be successfully post‐cervical inseminated with doses containing 1.5 × 109 sperm cells in the absence of the boar during insemination without impairing the reproductive performance. 相似文献
4.
Patricia M. Harveson Roel R. Lopez Bret A. Collier Nova J. Silvy 《Biological conservation》2007,134(3):321-331
Rapid human population growth and urbanization have had a negative impact on species biodiversity. As competition for resources between man and wildlife continues, it is important to understand the effects of urbanization on species. Endangered Key deer (Odocoileus virginianus clavium) are endemic to the Florida Keys which have undergone rapid human population growth and development over the past 30 years. Our study objectives were to evaluate the impacts of urban development on Key deer habitat use, population dynamics, behavior, and body mass. We used data from two comprehensive studies on Key deer spanning 30 years to evaluate these changes. Our results suggest that Key deer have become more urbanized, using urban areas more today than they did 30 years ago. Contrary to our predictions, survival was higher for more urban deer than for less urban deer. Problems still exist with mortality factors heavily impacting some portions of the deer population including lower survival associated with less urban male deer. Analysis of Key deer body mass also was converse to our predictions as deer weights appear to have increased over time. Collectively, our results suggest that over the past 30 years Key deer have become more urbanized and that deer plasticity has allowed them to adapt and persist in an urbanizing environment. However, the future ability of Key deer to persist in an environment with continued urban development is unknown. At some threshold, urban development would become unsustainable and unlike other forms of habitat change or environmental disturbances, urban development is in most cases irreversible requiring careful planning in habitat conservation strategies. 相似文献
5.
Gebauer R Volarík D Urban J Børja I Nagy NE Eldhuset TD Krokene P 《Tree physiology》2011,31(10):1103-1113
Conifers and other trees are constantly adapting to changes in light conditions, water/nutrient supply and temperatures by physiological and morphological modifications of their foliage. However, the relationship between physiological processes and anatomical characteristics of foliage has been little explored in trees. In this study we evaluated needle structure and function in Norway spruce families exposed to different light conditions and transpiration regimes. We compared needle characteristics of sun-exposed and shaded current-year needles in a control plot and a thinned plot with 50% reduction in stand density. Whole-tree transpiration rates remained similar across plots, but increased transpiration of lower branches after thinning implies that sun-exposed needles in the thinned plot were subjected to higher water stress than sun-exposed needles in the control plot. In general, morphological and anatomical needle parameters increased with increasing tree height and light intensity. Needle width, needle cross-section area, needle stele area and needle flatness (the ratio of needle thickness to needle width) differed most between the upper and lower canopy. The parameters that were most sensitive to the altered needle water status of the upper canopy after thinning were needle thickness, needle flatness and percentage of stele area in needle area. These results show that studies comparing needle structure or function between tree species should consider not only tree height and light gradients, but also needle water status. Unaccounted for differences in needle water status may have contributed to the variable relationship between needle structure and irradiance that has been observed among conifers. 相似文献
6.
A neutralizing antibody selected from plasma cells that binds to group 1 and group 2 influenza A hemagglutinins 总被引:2,自引:0,他引:2
Corti D Voss J Gamblin SJ Codoni G Macagno A Jarrossay D Vachieri SG Pinna D Minola A Vanzetta F Silacci C Fernandez-Rodriguez BM Agatic G Bianchi S Giacchetto-Sasselli I Calder L Sallusto F Collins P Haire LF Temperton N Langedijk JP Skehel JJ Lanzavecchia A 《Science (New York, N.Y.)》2011,333(6044):850-856
The isolation of broadly neutralizing antibodies against influenza A viruses has been a long-sought goal for therapeutic approaches and vaccine design. Using a single-cell culture method for screening large numbers of human plasma cells, we isolated a neutralizing monoclonal antibody that recognized the hemagglutinin (HA) glycoprotein of all 16 subtypes and neutralized both group 1 and group 2 influenza A viruses. Passive transfer of this antibody conferred protection to mice and ferrets. Complexes with HAs from the group 1 H1 and the group 2 H3 subtypes analyzed by x-ray crystallography showed that the antibody bound to a conserved epitope in the F subdomain. This antibody may be used for passive protection and to inform vaccine design because of its broad specificity and neutralization potency. 相似文献
7.
Protein aggregation is involved in the pathogenesis of neurodegenerative diseases and hence is considered an attractive target for therapeutic intervention. However, protein-protein interactions are exceedingly difficult to inhibit. Small molecules lack sufficient steric bulk to prevent interactions between large peptide surfaces. To yield potent inhibitors of beta-amyloid (Abeta) aggregation, we synthesized small molecules that increase their steric bulk by binding to chaperones but also have a moiety available for interaction with Abeta. This strategy yields potent inhibitors of Abeta aggregation and could lead to therapeutics for Alzheimer's disease and other forms of neurodegeneration. 相似文献
8.
A transient rise in tropical sea surface temperature during the Paleocene-Eocene thermal maximum 总被引:1,自引:0,他引:1
Zachos JC Wara MW Bohaty S Delaney ML Petrizzo MR Brill A Bralower TJ Premoli-Silva I 《Science (New York, N.Y.)》2003,302(5650):1551-1554
The Paleocene-Eocene Thermal Maximum (PETM) has been attributed to a rapid rise in greenhouse gas levels. If so, warming should have occurred at all latitudes, although amplified toward the poles. Existing records reveal an increase in high-latitude sea surface temperatures (SSTs) (8 degrees to 10 degrees C) and in bottom water temperatures (4 degrees to 5 degrees C). To date, however, the character of the tropical SST response during this event remains unconstrained. Here we address this deficiency by using paired oxygen isotope and minor element (magnesium/calcium) ratios of planktonic foraminifera from a tropical Pacific core to estimate changes in SST. Using mixed-layer foraminifera, we found that the combined proxies imply a 4 degrees to 5 degrees C rise in Pacific SST during the PETM. These results would necessitate a rise in atmospheric pCO2 to levels three to four times as high as those estimated for the late Paleocene. 相似文献
9.
Direct HPLC analysis of quercetin and trans-resveratrol in red wine,grape, and winemaking byproducts 总被引:1,自引:0,他引:1
Careri M Corradini C Elviri L Nicoletti I Zagnoni I 《Journal of agricultural and food chemistry》2003,51(18):5226-5231
A simple and fast reversed-phase HPLC method using diode array detection was developed and validated for the simultaneous determination of trans-resveratrol and quercetin in Sicilian red wine from the Nero d'Avola red grape variety. Investigation was also extended to the quantitative determination of resveratrol and quercetin in grape skins and winemaking byproducts obtained from the same cultivar. Samples were eluted using a C18 narrow-bore column under isocratic conditions in less than 20 min. Quantification of trans-resveratrol and quercetin in red wine was performed without any sample pretreatment, whereas the determination of these phenolic compounds in grape skins and wine pomage required a solvent extraction procedure. Linearity was demonstrated over the 0.39-12.5 and 0.45-57.6 microg/mL range for trans-resveratrol and quercetin, respectively. Detection limits in real samples were in the low ppm level (0.07 mg/L for trans-resveratrol and 0.12 mg/L for quercetin). The HPLC-UV/DAD method was applied for the routine analyses of red wine and grape skin and winemaking byproduct extracts to evaluate their trans-resveratrol and quercetin content. In particular, a very high content of quercetin was found in wine pomace, suggesting the use of this wine byproduct as a potential source of this health-promoting phenolic compound. 相似文献
10.
Reticuloendotheliosis virus (REV), a common pathogen of poultry, has been associated with runting and neoplasia in an endangered subspecies of grouse, the Attwater's prairie chicken. The pathogenesis of REV infection was examined in experimentally infected prairie chickens. Three groups of four Attwater's/greater prairie chicken hybrids were infected intravenously with varying doses (tissue culture infective dose [TCID50], 200, 1000, and 5000) of a prairie chicken-isolated REV. A fourth group of four birds was not infected. Blood was collected prior to infection, and at various times up to 37 wk following infection. Peripheral blood mononuclear cells were examined for integrated proviral DNA by a single-amplification polymerase chain reaction (PCR) and nested PCR of a region within the pol gene. The nested PCR identified REV proviral DNA in all REV-inoculated birds by 2 wk postinfection and confirmed chronic infection throughout the study. With the exception of a bird that died from bacterial pneumonia 8 wk postinfection, neoplasia, resembling that seen in naturally occurring infections, was observed in all birds, even those receiving as little as 200 TCID50 of virus. 相似文献