全文获取类型
收费全文 | 194篇 |
免费 | 11篇 |
专业分类
林业 | 3篇 |
2篇 | |
综合类 | 41篇 |
农作物 | 2篇 |
水产渔业 | 6篇 |
畜牧兽医 | 134篇 |
园艺 | 4篇 |
植物保护 | 13篇 |
出版年
2023年 | 1篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 6篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 6篇 |
1996年 | 14篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1941年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有205条查询结果,搜索用时 15 毫秒
51.
Holloway NM Lakritz J Tyler JW Carlson SL 《American journal of veterinary research》2002,63(4):476-478
OBJECTIVE: To determine serum lactoferrin concentrations (SLFC) in neonatal calves before and after ingestion of colostrum and to develop models that predict SLFC as a function of colostral lactoferrin concentrations (CLFC) in calves. ANIMALS: 13 Holstein calves. PROCEDURE: Calves were fed 4 L of colostrum via oroesophageal feeder within 3 hours after birth. Serum samples were collected before ingestion of colostrum (day 0) and 2, 4, 6, and 7 days after birth. Colostrum and serum IgG concentrations were measured by use of radial immunodiffusion. The CLFC and SLFC were determined by use of an ELISA. RESULTS: Mean +/- SD SLFC on days 0, 2, 4, 6, and 7 were 2.5+/-1.6 (range 0.47 to 71), 6.0+/-3.0 (range 2.0 to 16.6), 12.0+/-12.4 (range 0.0 to 43.5), 171+/-13.6 (range 2.2 to 39.4), and 13.6+/-16.4 (range 0.0 to 43.8) mg/ml, respectively. The SLFC on days 6 and 7 differed significantly from SLFC on day 0. The model that best estimated SLFC on day 6 predicted that (SLFC)2 was a function of the logarithm of relative efficiency of passive transfer (REPT) and ([CLFC]2 x [REPT]2), where R2 = 0.4. The model for SLFC on day 7 predicted that (SLFC)2 was a function of log(REPT), where R2 = 0.44. CONCLUSIONS AND CLINICAL RELEVANCE: Definitive evidence for passive transfer of lactoferrin via colostrum is lacking, because SLFC on day 2 or 4 were not significantly different than day 0. Relative efficiency of lactoferrin absorption was directly related to SLFC on day 6 but inversely related to SLFC on day 7. 相似文献
52.
SUMMARY An investigation of sheep flocks with unknown histories of fleece derangement, selected at random from the main sheep raising areas of New South Wales, showed that Psorergates ovis was present in 53 of the 177 flocks surveyed and In 162 of the 3495 sheep examined. Of the single causes of fleece derangement, the most prevalent was grass seed contamination (15.7%) followed by Infestation with sheep body lice, Bovicola ovis, (14.7%) and Infestation with Itch mite (7.8%). The prevalence of fleece derangement was significantly higher on sheep In which lice were the only ectoparasites found than on those In which Itch mites were the only ectoparasites present. The greatest prevalence of P ovis was In flocks In the Young, Yass, Mudgee and Tenterfield districts. In most affected flocks, more than one potential cause of fleece derangement was present. Itch mite Infestation was more prevalent in flocks that received no treatment for ectoparasites than in those that had been treated in the year preceding the survey. Our results did not support a commonly held belief among farmers that arsenical compounds control Infestations of Itch mites more effectively than other types of pesticides. There was no significant difference in prevalence of fleece derangement between flocks treated with different pesticide groups and those that received no treatment, but mean fleece derangement score was significantly lower in sheep treated with organophosphates than in untreated sheep. Infestations of lice were significantly more prevalent in sheep from flocks treated with synthetic pyrethroids than from those treated with organophosphates or those that received no treatment. 相似文献
53.
54.
55.
D. Murgia M. Pivetta K. Bowlt C. Volmer A. Holloway R. Dennis 《The Journal of small animal practice》2014,55(8):431-435
This case report describes three brachycephalic dogs with intranasal epidermoid cysts that were causing additional upper airway obstruction. Although epidermoid cysts have been described in several locations in dogs, to the authors’ knowledge intranasal epidermoid cysts have not been previously reported. All dogs had mucopurulent to haemorrhagic nasal discharge. Magnetic resonance imaging of the head revealed the presence of unilateral or bilateral intranasal cystic lesions obstructing the nasal cavities partially or completely, with atrophy of the ipsilateral nasal turbinates. The cystic lesions were surgically excised in all dogs using a modified lateral alveolar mucosal approach to the affected nasal cavity. Aerobic, anaerobic and fungal culture of the cystic contents were negative and histology of the excised tissue was consistent with a benign intranasal epidermoid cyst in each dog. Upper airway obstruction was clinically improved in two dogs. 相似文献
56.
The H2O-saturated solidus of a model mantle composition (Kilborne Hole peridotite nodule, KLB-1) was determined to be just above 1000°C from 5 to 11 gigapascals. Given reasonable H2O abundances in Earth's mantle, an H2O-rich fluid could exist only in a region defined by the wet solidus and thermal stability limits of hydrous minerals, at depths between 90 and 330 kilometers. The experimental partial melts monotonously became more mafic with increasing pressure from andesitic composition at 1 gigapascal to more mafic than the starting peridotite at 10 gigapascals. Because the chemistry of the experimental partial melts is similar to that of kimberlites, it is suggested that kimberlites may be derived by low-temperature melting of an H2O-rich mantle at depths of 150 to 300 kilometers. 相似文献
57.
J Christensen-Dalsgaard W Dappen SV Ajukov ER Anderson HM Antia S Basu VA Baturin G Berthomieu B Chaboyer SM Chitre AN Cox P Demarque J Donatowicz WA Dziembowski M Gabriel DO Gough DB Guenther JA Guzik JW Harvey F Hill G Houdek CA Iglesias AG Kosovichev JW Leibacher P Morel CR Proffitt J Provost J Reiter EJ Rhodes FJ Rogers IW Roxburgh MJ Thompson RK Ulrich 《Science (New York, N.Y.)》1996,272(5266):1286-1292
Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations. 相似文献
58.
Observations of ozone formation in power plant plumes and implications for ozone control strategies 总被引:1,自引:0,他引:1
Ryerson TB Trainer M Holloway JS Parrish DD Huey LG Sueper DT Frost GJ Donnelly SG Schauffler S Atlas EL Kuster WC Goldan PD Hubler G Meagher JF Fehsenfeld FC 《Science (New York, N.Y.)》2001,292(5517):719-723
Data taken in aircraft transects of emissions plumes from rural U.S. coal-fired power plants were used to confirm and quantify the nonlinear dependence of tropospheric ozone formation on plume NO(x) (NO plus NO(2)) concentration, which is determined by plant NO(x) emission rate and atmospheric dispersion. The ambient availability of reactive volatile organic compounds, principally biogenic isoprene, was also found to modulate ozone production rate and yield in these rural plumes. Differences of a factor of 2 or greater in plume ozone formation rates and yields as a function of NO(x) and volatile organic compound concentrations were consistently observed. These large differences suggest that consideration of power plant NO(x) emission rates and geographic locations in current and future U.S. ozone control strategies could substantially enhance the efficacy of NO(x) reductions from these sources. 相似文献
59.
Multiphasic retention deficits at periodic intervals after passive-avoidance learning 总被引:2,自引:0,他引:2
Aftetr one-trial passive-avoidance training, indepelenet groups of rats tested promptly after training or at successive 6-hour intervals displayed a repetitive pattern of high then low retention scores. These results suggest that some physiological rhythm may interact with retention performance. 相似文献
60.
de Gouw JA Middlebrook AM Warneke C Ahmadov R Atlas EL Bahreini R Blake DR Brock CA Brioude J Fahey DW Fehsenfeld FC Holloway JS Le Henaff M Lueb RA McKeen SA Meagher JF Murphy DM Paris C Parrish DD Perring AE Pollack IB Ravishankara AR Robinson AL Ryerson TB Schwarz JP Spackman JR Srinivasan A Watts LA 《Science (New York, N.Y.)》2011,331(6022):1295-1299
A large fraction of atmospheric aerosols are derived from organic compounds with various volatilities. A National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft made airborne measurements of the gaseous and aerosol composition of air over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico that occurred from April to August 2010. A narrow plume of hydrocarbons was observed downwind of DWH that is attributed to the evaporation of fresh oil on the sea surface. A much wider plume with high concentrations of organic aerosol (>25 micrograms per cubic meter) was attributed to the formation of secondary organic aerosol (SOA) from unmeasured, less volatile hydrocarbons that were emitted from a wider area around DWH. These observations provide direct and compelling evidence for the importance of formation of SOA from less volatile hydrocarbons. 相似文献