首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   104篇
  免费   8篇
林业   10篇
农学   1篇
  23篇
综合类   4篇
农作物   10篇
水产渔业   20篇
畜牧兽医   31篇
园艺   9篇
植物保护   4篇
  2024年   1篇
  2022年   5篇
  2021年   5篇
  2020年   8篇
  2019年   14篇
  2018年   7篇
  2017年   6篇
  2016年   4篇
  2015年   7篇
  2014年   6篇
  2013年   9篇
  2012年   7篇
  2011年   12篇
  2010年   6篇
  2009年   1篇
  2008年   6篇
  2007年   2篇
  2006年   1篇
  2005年   3篇
  2003年   1篇
  2002年   1篇
排序方式: 共有112条查询结果,搜索用时 9 毫秒
91.
The effects of temperature, photon flux density and photoperiod on the growth rate of female gametophytic and tetrasporophytic thalli of Chondracanthus chamissoi from four populations along the Chilean coast were studied in vitro. Both reproductive phases survived and grew under all the conditions tested, with growth rates varying between 0.1 and 7.5% day?1. The results showed higher growth rates with increases in temperature and photon flux density levels. The growth rate was higher in female gametophytic thalli in almost all treatments. The photoperiod did not cause significant differences in the growth rate for either reproductive phases in any of the populations studied. Temperature was the principal factor affecting the growth rate of C. chamissoi.  相似文献   
92.
PRACTICAL RELEVANCE: Blindness and behavioural changes occur relatively commonly in cats, either separately or in combination, causing devastating consequences for the cat and owner. Blindness can be caused by primary ophthalmic, metabolic or intracranial disease. Similarly behavioural changes may be the primary result of intracranial or systemic disease, but also occur secondarily to visual deficits or changes in interaction with the external environment (ie, non-medical problems). The anatomical pathways involved in vision are very close to those involved in behavioural regulation. It is, therefore, likely that a brain lesion (especially a forebrain lesion) that causes blindness will also cause behavioural abnormalities. CLINICAL CHALLENGES: In cases of partial or unilateral blindness, obvious visual deficits may not be apparent to the owner or clinician. Rather, the visual impairment may manifest more subtly as changes in behaviour, reluctance to jump or unwillingness to go outside. Similarly, behavioural problems may be episodic and, hence, a cat presenting with behavioural disturbances may appear clinically normal on evaluation. Behavioural changes are unlikely to be noticed unless marked and associated with bilateral blindness or advanced systemic illness. AUDIENCE: This article discusses these two major disorders separately, with the aim of highlighting for the clinician some of the important aspects of the general clinical and neurological examination that can be performed to identify these challenging cases.  相似文献   
93.
An 8-year-old cat was presented with severe neurological deficits secondary to a traumatic cervical spinal cord injury caused by an airgun pellet. This report describes, for the first time, the myelographic findings of a dural rupture in a cat and also describes a bilateral Horner’s syndrome in a cat.  相似文献   
94.
The extraction capacity of several solvent mixtures and comparison between alkaline and acid hydrolysis to extract free and bound minor polar compounds in oat samples were carried out. The extraction yield of each method was evaluated by correlating several spectrophotometric indices (absorption at 320 nm and total phenolic compounds by the Folin–Ciocalteu method) with HPLC-MS and the antioxidant activities of the oat extracts (DPPH radical method). The results showed that methanol and alkaline hydrolysis reported the highest recovery of polar compounds, and spectrophotometric indices overestimated the content of these compounds. Antioxidant compounds of five Romanian oat samples, named Comun, Jeremy, Mures, Lovrin 1, Lovrin 27-T were determined. Large intervarietal differences in phenolic compounds and their antioxidant activities among oat varieties were detected. Total minor polar contents content was in the range of 1179.47 and 1897.18 mg/kg of seed. According to the literature, we found that the majority of the minor polar compounds existed in bound form.  相似文献   
95.
Aroma compound properties in food matrices, such as volatility and diffusivity, have to be determined to understand the effect of composition and structure on aroma release and perception. This work illustrates the use of mass transfer modeling to identify diffusion and partition properties of ethyl hexanoate in water and in carrageenan matrices with various degrees of structure. The comparison of results obtained with a diffusive model to those obtained with a convective model highlights the importance of considering the appropriate transfer mechanism. Modeling of the preliminary experimental steps ensures correct estimation of the conditions for the main aroma release step. The obtained values of partition and diffusion coefficients are in agreement with those found in the literature (either experimentally determined or predicted by theoretical equations) and demonstrate that the structure level of carrageenan matrices has little influence on diffusion properties of ethyl hexanoate (less than 20%).  相似文献   
96.
Aiming at determining the prevalence and the risk factors associated to astrovirus infection in puppy, fecal samples were collected in 316 puppies (age from 5 to 14 weeks of age) from 33 French breeding kennels. Data were registered for each puppy, including age, breed, gender, origin of the dog, and feces quality. The samples were tested by specific RT-PCR for the presence of canine astrovirus. Astroviruses were identified in 20.9% (66/316) of the puppies and in 42% (14/33) of the breeding kennels. Young puppies (i.e. <7 weeks of age) and puppies from large breeding kennels were more likely to be infected by the astrovirus. No association between the quality of feces and astrovirus infection could be determined in this survey.  相似文献   
97.
98.
The aim of this study was to evaluate a range of statistical and geostatistical methods for their usefulness in providing insights into how highly pathogenic avian influenza (HPAI) subtype H5N1 might spread through a national population of village poultry. The insights gained allow the generation of disease dispersion hypotheses. The case study data set consisted of 161 outbreaks of HPAI subtype H5N1 in village poultry reported in Romania between October 2005 and June 2006. Reports of village outbreaks (%) occurred in three waves: October-December (14%), February-March (16%), and May-June (68%). Risk mapping - based on variography and kriging - was used to visualize the evolution of the epidemic. Outbreaks first appeared in eastern and southern Romania, particularly within an area that forms part of the Danube River Delta. The largest phase of the epidemic affected villages in all parts of central, southern, and eastern Romania, but outbreaks were clustered in central Romania. Outbreaks spread in an east to west direction. By using geostatistical visualisation and spatial statistics, the evolution of the epidemic could be characterised into two parts: disease introduction, local spread, and sporadic outbreaks, and long-distance disease spread with rapid epidemic propagation. This is consistent with the hypothesis that the environment and landscape (specifically the Danube River Delta) played a critical role in the introduction and initial spread of HPAI subtype H5N1 during the autumn and winter of 2005, and that the movement of poultry might have introduced the infection into central Romania during the spring and summer of 2006. Further research focusing on the spatio-temporal interface between the two parts of the epidemic might reveal how and why it progressed from a confined, local epidemic to a large, national epidemic. Such information would assist efforts to limit the global spread of HPAI subtype H5N1.  相似文献   
99.
100.
Parentage analysis in aquaculture determines genealogical relationships between broodstock and progeny when the parents are unknown. Thus, parentage analysis is a useful tool to establish pedigree reports in molecular‐assisted selection programs. Here, we evaluated 10 heterologous microsatellite markers for parentage assignment in abalone hybrids produced from 43 abalone broodstocks of red abalone (Haliotis rufescens) and Japanese abalone (H. discus hannai). The allele frequencies, exclusion probabilities and broodstock contributions were calculated using CERVUS, PAPA and GERUD software. The polymorphic information content (PIC) values showed that most of the microsatellite loci were highly informative (>0.7) and more than 90% of parentage assignment was possible with a minimum of 5–6 microsatellite markers. Parentage assignment for hybrid and pure‐red progeny showed a better performance than pure‐Japanese progeny. This result could be due to the high level of allele loss in the parental genotypes. In addition, results indicated that only two sires contributed over 80% and 90% of red and hybrid progenies, respectively. This study gives a new molecular tool to support marker‐assisted selection in abalone hybrids produced in Chile.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号