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1.
The phylogenetic relationship among 30 accessions belonging to nine species of the genus Echinochloa Beauv. was studied on the basis of the sequence of three non-coding regions ( trn T-L, trn L-F intergenic spacers, and trn L intron) of chloroplast DNA (cpDNA). A strict consensus parsimonious tree of the three most parsimonious trees derived from 25 polymorphic sites (six indels and 19 substitutions) in the total sequences, ranging from 1715–1760 bp, represented five groups: (i) Echinochloa oryzicola Vasing. and Echinochloa stagnina Beauv. from Thailand; (ii) Echinochloa crus-galli Beauv. complex; (iii) Echinochloa crus-pavonis Schult; (iv) Echinochloa colonum Link. and Echinochloa frumentacea Link.; and (v) the African species, Echinochloa obtusiflora Stapf and Echinochloa stagnina . Japanese barnyard millet ( Echinochloa esculenta H. Scholz) and various weedy varieties of E. crus-galli and Echinochloa oryzoides Fritsch had quite similar sequences and formed the E. crus-galli complex, which was characterized by six substitutions. A cultivated form of E. oryzicola (Mosuo barnyard millet) and various morphological and agronomical forms of E. oryzicola were characterized by two indels. Indian barnyard millet ( E. frumentacea ) and its wild counterpart ( E. colonum ) were characterized by five substitutions. Domestication as millets and adaptation to paddy environments as mimic weeds might occur after the divergence of species in the Asian Echinochloa .  相似文献   
2.
This study was carried out to examine the possibility of utilizing Bidens pilosa , a weed widely distributed in the subtropics and the tropics, for weed and plant fungus control. The extract of B. pilosa shows strong phytotoxic action against the growth of Raphanus sativus and Echinochloa crus-galli and antifungal activity against phytopathogens in bioassays. The extract of the roots exhibited plant growth inhibitory activity more than those of the leaves and stems. Fifteen phenolic compounds, including pyrocatechin, salicylic acid, p -vinylguaiacol, dimethoxyphenol, eugenol, 4-ethyl-1,2-benzenediol, iso- vanillin, 2-hydroxy-6-methylbenzaldehyde, vanillin, vanillic acid, p -hydroxybenzoic acid, protocatechuic acid, p -coumaric acid, ferulic acid, and caffeic acid were identified by gas chromatography–mass spectrometry. Caffeic acid was in the highest amount among the detected substances. Dimethoxyphenol and vanillic acid were found only in the roots of B. pilosa . Ferulic acid and p -hydroxybenzoic acid were higher in the roots than in the leaves and stems. These identified constituents might be responsible for the phytotoxic and fungitoxic activities of B. pilosa.  相似文献   
3.
A drastic population change in Japanese sardine (Sardinops melanostictus) has been noted as being related to winter sea surface temperature (SST) in the Kuroshio Extension region. The former studies suggest two possible explanations. One is that temperature itself affects sardine. The other is that SST represents the environmental change of the Kuroshio Extension region and other causes directly affecting sardine. In this study, we found that sardine mortality from post‐larva to age 1 negatively correlated with the winter mixed layer depth (MLD) in the Kuroshio Extension region from 1979 to 1993. During the period of a deep winter mixed layer (during the early 1980s), sardine mortality was low, whereas mortality was high when the winter mixed layer was shallow (during the late 1980s to early 1990s). By using a lower trophic‐level ecosystem model forced by the observed time series of MLD, SST, light intensity and nutrient data, we found that the estimated spring zooplankton density drastically varies from year to year and has a significant negative correlation with sardine mortality. The inter‐annual variation of spring zooplankton density is caused by the winter MLD variation. During the deep winter mixed layer years, a phytoplankton bloom occurs in spring, whereas during the shallow winter mixed layer years, the bloom occurs in winter. The results of our study suggest that the decline in the Japanese sardine population during the late 1980s to early 1990s was due to an insufficient spring food supply in the Kuroshio Extension region where sardine larvae and juvenile are transported.  相似文献   
4.
The aim of this study was to evaluate the prognostic value of concurrent measurement of serum phosphorylated neurofilament heavy subunit (pNF-H) concentration and intramedullary T2W hyperintensity in paraplegic to paraplegic dogs. Our hypothesis was that concurrent measurement of these would provide a more accurate prediction of functional outcome in dogs with thoracolumbar intervertebral disc herniation (IVDH). A prospective case-control clinical study was designed using 94 dogs with acute onset of thoracolumbar IVDH. The association of serum pNF-H concentration, T2W hyperintensity on sagittal MRI (T2H/L2), deep pain perception and surgical outcome were evaluated with logistic regression analysis after three months for all 94 surgically treated dogs. Sensitivity to predict non-ambulatory outcome was compared among pNF-H and T2H/L2 and combination of both. Logistic regression analysis indicated that serum pNF-H concentration and T2H/L2 were significantly correlated with surgical outcome (P<0.05); however, deep pain perception was not (P=0.41). The results of logistic regression analysis indicated that the odds ratios of unsuccessful long-term outcome were 2.6 for serum pNF-H concentration, 1.9 for T2H/L2 and 2.3 for deep pain sensation. The sensitivity and specificity to predict non-ambulatory outcome for using serum parameter pNF-H>2.6 ng/ml, using T2H/L2 value of>0.84 and using both serum pNF-H and T2H/L2, were 95% and 75.7%, 65% and 86.5%, and 90.0% and 97.5%, respectively. Therefore, combined measurements of serum pNF-H and T2H/L2 might be useful for predicting long-term outcome in dogs with thoracolumbar IVDH.  相似文献   
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The relationships between fishing ground locations of Pacific saury (Cololabis saira) and the two Oyashio fronts, the offshore front between 146oE and 155oE and the coastal Oyashio intrusion, before the saury fishing season, were examined using data from 1971 to 1991. Interannual geographical shifts of both the offshore Oyashio front and saury fishing grounds had a dominant interdecadal fluctuation. In years when the offshore front shifted north (south), the fishing grounds were formed relatively nearshore (offshore). When the offshore front shifted north, the fishing grounds were formed further nearshore in years the coastal Oyashio intrusion extended south. When the offshore front shifted south, on the other hand, the southward extension of the coastal intrusion did not necessarily cause formation of coastal fishing grounds. These results showed that locations of the fishing grounds depend not only on local and instantaneous oceanographic environments around the fishing grounds, but also on oceanographic conditions over an extensive range of the Oyashio area. This might indicate that the ecology of the saury's northward migration, through mixed water regions between the Kuroshio and Oyashio fronts in spring and summer, has a close relation to the shift of the offshore Oyashio front over a time range of months. A practical forecasting method for locations of saury fishing grounds is proposed based on the oceanography before the fishing season.  相似文献   
8.
Effect of the strain combination of the donor and recipient on production efficiency of W‐bearing sperm in mixed‐sex chimeric testes was analyzed. The combinations of the donors and recipients were White Leghorn (WL) and Rhode Island Red (RIR), and vice versa. Generated mixed‐sex chimeras that had the male phenotype at sexual maturity were classified into four groups: (1) a female WL donor and a male RIR recipient; (2) a male WL donor and a female RIR recipient; (3) a female RIR donor and a male WL recipient; (4) a male RIR donor and a female WL recipient. The mean number of W‐bearing sperm detected by in situ hybridization among 10 000 sperm observed were 147, 165, 30 and 45 in groups 1, 2, 3 and 4, respectively. The numbers in groups 1 and 2 were both significantly higher than those of groups 3 and 4 (P < 0.05). The combination of a WL donor and a RIR recipient produced W‐bearing sperm more efficiently than the reverse combination.  相似文献   
9.
分步型流域“降雨-流出”过程数值模拟方法的研究   总被引:1,自引:0,他引:1  
流域地表流出的计算是水文学的一个重要研究课题。本研究以黄土高原北部的六道沟流域为流域模型,在确定试验流域地形和土壤物理性质的基础上,利用运动波理论和拟河道网开发分布型流域的"降雨-径流"过程的数值计算方法,对观测流量数值模拟结果的分析表明,该计算方法适用于北部黄土高原的实际,研究结论为该区域的地表水资源的推求提供了一种有效的数值计算方法。  相似文献   
10.
In order to examine the relationship between white scour and fatty acids, we added fatty acids to the milk replacer. Twenty healthy Holstein calves were divided into 4 groups, five calves per group; a control group with no fortified fatty acid, and 3 groups fed either with oleic, stearic, or palmitic acid, respectively. The calves were fed milk replacer (5% of the calf's body weight) twice a day but the fatty acids (2 wt % of milk replacer) were added only once. The fecal and blood samples were obtained at 0, 12, 24, 36, and 48 h after feeding of the acids. All five calves in the palmitic acid group, and 3 out of 5 calves each in the stealic and the oleic acid groups had whitish feces after feeding fatty acid. The stearic acid group had a significantly elevated stearic acid concentration in the feces during 24–36 h compared to the pre-feeding level. The fecal concentration of palmitic acid increased significantly at 24–36 h in the palmitic acid group. We concluded that the long-chain saturated fatty acids are one of the causes of white scour in calves.  相似文献   
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