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81.
During examination of lysozyme concentration we have found out that 90.3% of calf sera had the lysozyme concentration to 0.5 microgram . ml-1, 5.7% of sera showed zero values and only 4.0% of sera values from 0.5 to 1.4 microgram . ml-1. A higher lysozyme content was recorded in sera of calves up to the age of ten days in comparison with sera of calves after the second week post natum. The lysozyme concentration showed in calves a two-phase increase in the age dynamics up to the seventh to eighth week of life with a peak in second and fifth to eighth week of age. The increase rate in the first phase and the time onset of increase in the second phase were in negative, and/or positive relation to the level of immunity obtained through colostrum. The lysozyme concentration in serum of dairy cows was on fourth day post partum as much as ten times higher than in serum of their progenies 48 hours after parturition. In first colostrum the lysozyme concentration fluctuated within the range of 0.15 to 0.65 microgram X ml-1, with an average of 0.30 microgram X ml-1. The concentration of lysozyme and immunoglobulins of the IgG and IgM class in colostrum showed a contrary trend in first and second milk yield, with a tendency towards increase for lysozyme and towards decrease for immunoglobulins.  相似文献   
82.
Three main factors underlying the immunity state of newborn calves are evaluated. During the absorption of colostral immunoglobulins the immunoprotein profile of a newborn calf is influenced by the following factors (arranged according to importance): volume of the first colostrum taken in, time of the first drinking, and immunoglobulin concentration (IgG and IgM) in colostrum. When given 1.1 or 2.0 litres of colostrum of about the same quality (as to immunity), the calves of the compared groups had significantly different levels of total serum Ig measured 24 hours after birth: 10.7 and 18.6 U ZST (P less than 0.05) and 48 hours after birth: 11.7 and 19.7 U ZST (P less than 0.01). A significant difference in total serum proteins was observed only in the 48th hour post partum (54.4 and 63.6 g per litre; P less than 0.05). At the intake of 1.5 litres of colostrum within two and five hours after birth, with the same total intake of the sum of IgG and IgM in the groups, the calves exhibited, in the 24th hour, total serum Ig levels of 14.4 and 12.4 U ZST (P greater than 0.05) respectively, and 56.0 and 47.9 g per litre (P greater than 0.05) of total serum protein, respectively. With a different concentration of colostral IgG (122.0 or 77.0 g per litre) the statistically significant Ig absorption into blood was adequately different (17.2 and 10.0 U ZST, respectively, P less than 0.05). The differences in the concentration of total serum Ig and total proteins between the 24th and 48th hour after birth were only very small and statistically insignificant. Regression analysis proved a significant relation (P less than 0.01) between the level of total serum Ig 24 and 48 hours after birth and the total amount of IgG and IgM taken in with the first colostrum. The calves coming from primiparae had a lower immunity (P less than 0.01) in comparison with the calves of multiparae. A similar relation in the absorption of colostral Ig was observed when the spontaneously born calves were compared with those born by the Caesarean section (P less than 0.01).  相似文献   
83.
Rooting of carnation cuttings was promoted by storage temperatures above 0°C with an inverse relationship between the level of temperature and the duration of the treatment. The effect of temperature on root dry weight was far more important than the effect of duration of storage. A long storage and a high temperature increased the incidence of Fusarium. Storage at temperatures lower than 13°C gave better results with auxin applied after storage, while temperatures higher than 13°C gave better results with a pre-treatment of auxin. During storage for 14 days at 9°C, the position of the cuttings had no clear effect on rooting. Horizontal storage, however, appeared to be unfavourable. Removal of 0.5 cm of the base of the stem after storage nullified the storage effect. Carbohydrates in the removed pieces decreased during storage, more so at 13°C than at 0°C. Anatomically, an acceleration of cell division at the base of the cutting was observed during storage at 9°C as compared to 0°C.At a commercial nursery, storage of cuttings for 12 days at 14°C improved rooting by 84% compared to storage at 0°C. The presented technique tends to shorten the expensive and vulnerable period from planting to rooting.  相似文献   
84.
This study of a water cycle was conducted in an evergreen forest located in the Mekong River Basin in central Cambodia. At the observation site, we measured the dynamics of the spatial distribution of groundwater levels. The groundwater movement was analyzed two-dimensionally using boundary conditions and parameters that had been observed in the field. The climate in the research area is dominated by two seasons, which occur annually: a rainy and a dry season. The groundwater levels are generally high during the rainy season and low during the dry season. Groundwater levels were measured along a stream, which flowed through the study site. The streambed was visible at the head of the stream in January. At the next downriver well point, the streambed appeared in March. Finally, it became visible at all well points in April, meaning that surface runoff had disappeared temporarily and instead flowed underground during the ensuing dry period. Groundwater levels of the studied lateral flow perpendicular to the stream that seeped and infiltrated into the stream were 1.2–2.5 m deep (in April), which was the lowest level recorded for the year. During that period, the depth of the groundwater of the studied lateral flow fell by as much as 56 mm per month. In addition, the lateral flow groundwater infiltrated into groundwater of the stream during that period. The groundwater level fluctuation was estimated based on a two-dimensional analysis of lateral flow perpendicular to the stream using a numerical simulation model with soil physical parameters and observed boundary conditions. The observations of ground water fluctuations were well reproduced. Deep seepage of groundwater was estimated using a uniform boundary condition that allowed efflux through the bottom, estimated as being approximately 30 mm per year. The simulated deep seepage rate was considered plausible considering other hydrological components such as soil water storage fluctuation.  相似文献   
85.
The regeneration of haploid plantlets is considered as a bottleneck in rice anther culture. In this study, an antimitotic chromosome doubling method, simple and efficient, of androgenic haploid plantlets resulted in an efficient doubled haploid obtainment. Through chromosome doubling capacity comparison of the three antimitotic compounds (colchicine, trifluralin and oryzalin), colchicine at 500 and 625 mg/L without supplementing with DMSO was found to be the best antimitotic treatment, with a chromosome doubling capacity of 40%. Furthermore, the in vitro growth of plantlets was followed to analyse the effects of antimitotic compounds. Colchicine treatments were more toxic than dinitroanilines, and colchicine DMSO-supplemented treatments had significant lower values on shoot growth. On the other hand, dinitroaniline compounds impeded root growth, provoked helical growth of shoot and caused the apparition of white nodules in the base of the plantlet due to sprouting abortion. In this study, a protocol for doubled haploid plant recovery was established taking advantage from androgenic haploid plantlets in order to increase the number of doubled haploid plantlets produced after an anther culture protocol.  相似文献   
86.
Background: Metabolomic approaches, which include the study of low molecular weight molecules, are an emerging-omics technology useful for identification of biomarkers. In this field, nuclear magnetic resonance(NMR)spectroscopy has already been used to uncover(in) fertility biomarkers in the seminal plasma(SP) of several mammalian species. However, NMR studies profiling the porcine SP metabolome to uncover in vivo fertility biomarkers are yet to be carried out. Thus, this study aimed to evaluate...  相似文献   
87.
Generalist fish species can feed on a wide resource spectrum and across trophic levels depending on resource availability and trophic interactions. Crucian carp (Carassius carassius) represents a good candidate species to investigate variation in the trophic ecology of generalist fish as it can be found in highly variable fish communities and its resource use is well documented. In this study, we explored the trophic ecology of crucian carp at the individual and population levels using stable isotope and gut content analysis. We tested if trophic resource use varied according to lake productivity, predation risk, intra- and interspecific competition, or individual fish size. We found that crucian carp resource preference was highly variable among and within lakes. In predator-free lakes, small crucian carp occurred in high densities, showed increased interindividual specialisation, and relied mainly on pelagic zooplankton. In presence of predators, large crucian carp occurred in low densities and included greater proportions of benthic macroinvertebrates in their diet. This shift in resource use was further favoured in productive, shallow lakes where littoral prey were probably abundant. Resource partitioning was an important factor determining crucian carp niche use, as fish had higher trophic position in absence of other cyprinids. Crucian carp showed highly dynamic resource use and food preferences in response to variable environmental conditions. Overlooking complex diet preferences of generalist fish may lead to an oversimplification of freshwater community dynamics.  相似文献   
88.
89.
In September, a high mortality among eggs ofAdoxophyes orana was observed. Temperature effects were believed to be responsible. In controlled conditions, constant temperatures of 13 or 14°C proved lethal to most eggs, but mortality was about halved when temperature changes were gradual. Low temperature (5°C or less) for 6h was lethal when eggs were exposed within a few hours of oviposition. This was also due to a rapid change in temperature. Survival of eggs ofA. orana is most affected by long cool periods and is slightly affected by cold nights.  相似文献   
90.
The authors describe the synchronization of farrowing by the induction of parturition with a prostaglandin F2alpha analogue (Cloprostenol). The time sequence of the beginning of parturitions was recorded in 147 sows after administration of 175 microgram Cloprostenol. 93.7% of the parturitions take place between the 14th and 39th hour after administration, the peak time being between the 24th and 27th hour (31.2%). The schedule of the farrowing days is described as a prerequisite for a qualitative change in the organization of work in large pig herds.  相似文献   
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