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21.
ABSTRACT Two begomoviruses (Java virus-1 and Java virus-2), two satellite DNAs (DNAbeta01 and DNAbeta02), and a recombinant DNA (recDNA) were cloned from a single tomato plant from Indonesia with leaf curl symptoms, and the role of these satellite DNAs in the etiology of begomovirus disease was investigated. The genome organizations of the two viruses were similar to those of other Old World monopartite begomoviruses. Comparison of the sequences with other begomoviruses revealed that Java virus-1 was a newly described virus for which the name Tomato leaf curl Java virus (ToLCJAV) is proposed. Java virus-2 was a strain of Ageratum yellow vein virus (AYVV) (AYVV-[Java]). ToLCJAV or AYVV-[Java] alone did not induce leaf curl symptoms in tomato plants. However, in the presence of DNAbeta02, both ToLCJAV and AYVV-[Java] induced leaf curl symptoms in tomato plants. In the presence of DNAbeta01, these viruses induced mild leaf curl symptoms in tomato plants. The recDNA had a chimeric sequence, which arose from recombination among ToLCJAV, AYVV-[Java], DNAbeta01, and DNAbeta02; it was replicated only in the presence of AYVV-[Java] in tomato plants.  相似文献   
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Abstract

Many studies have evidenced the negative effects of synthetic fertilizers toward the environment and also the crop products itself. Hence, the improvement of organic fertilizers is necessary to resolve this problem. Seaweeds or marine macroalgae are considered to be an excellent natural resource in different aspects of agricultural fields. Brown macroalgae Turbinaria murayana (TM) is often found in Indonesian coastal areas with high bioavailability throughout the year. This study evaluated the potentials of TM as biofertilizer in tomato plants (Lycopersicum esculentum Mill.). Evaluation of phytohormones present in TM crude extract was conducted with high performance liquid chromatography (HPLC). Macro and micronutrients available in TM crude extract were determined by atomic absorbance spectroscopy (AAS). A concentration of 4% TM crude extract was applied to tomato plants. The vegetative properties of the treated tomatoes were observed such as growth and yield. Current results evidenced the presence of growth-promoting factors (kinetin, gibberellin and ABA) and essential elements (N, P, K, Ca, Fe and Mn) in TM crude extract. Application of 4% TM extract to tomato plants significantly increased vegetative growth compared to untreated plants; plant height, leaf number and branch number, approximately 58.4%, 87.5% and 200%, respectively. Similar results were also found in the response of generative growth. Application of 4% liquid extract significantly improved flower and fruit number compared to control; 53.6% and 125%, respectively. These results suggest that TM crude extract is a potential source for developing organic fertilizers.  相似文献   
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This research investigated the impact of modeling atrazine, metolachlor, and isoxaflutole/metabolite transport in artificially subsurface drained sites with temporally discrete rainfall data. Differences in considering rainfall distribution are unknown in regard to estimating agrochemical fluxes in the subsurface. The Root Zone Water Quality Model (RZWQM) simulated pesticide fate and transport at three subsurface drained sites: metolachlor/atrazine field experiment in Baton Rouge, LA (1987), and two isoxaflutole/metabolite field experiments in Allen County and Owen County, Indiana (2000). The modeling assumed linear, equilibrium sorption based on average reported physicochemical and environmental fate properties. Assumed rainfall intensity and duration influenced transport by runoff more than transport by subsurface drainage. As the importance of macropore flow increased, the necessity for using temporally discrete rainfall data became more critical. Long-term simulations indicated no significant difference between average or upper percentile (i.e., <2% difference in percent loss as a function of mass applied) atrazine, metolachlor, or isoxaflutole/metabolite loss through subsurface drainage among the three different rainfall assumptions. It was necessary (i.e., within 7% of predicted loss) to use hourly or average duration storm events as opposed to daily rainfall data for total (i.e., runoff and subsurface drainage) pesticide loss over the long term.  相似文献   
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The effectiveness of green mussel (Perna viridis) cultivation was compared between longline culture and the traditional bamboo stake method using different mussel densities in a rural area on the north coast of Java, Indonesia. The study took place in a rural area about 2 km north‐east from the city of Semarang where unsustainable shrimp and fish pond culture in the past has led to massive mangrove loss, spiralling environmental degradation and socio‐economic disintegration. Mangrove‐friendly alternatives for a sustainable socio‐economic recovery of local livelihoods are urgently being sought. Longlines were more successful than the stake method in spat collection. Longlines also showed a small but significantly higher relative weight gain and specific growth rate for mussels than bamboo stakes. Mussels in lower densities showed higher survival and grew to larger individual sizes, but initial seeding density had no significant effect on relative weight gain or specific growth rate per stocking. Slightly lower set‐up costs and time investment and somewhat higher yields for longlines give an almost twofold higher income per time unit of own time invested by the farmer for longline culture over the traditional stake culture method. The profitability of mussel culture using the stake method is below the average hourly wage for skilled labour, but above that when using the longline method. We conclude that green mussel culture using the longline system is feasible as an alternative to less sustainable forms of livelihood for the local communities in mangrove areas.  相似文献   
25.
This study evaluated the possible use of the fish SSN-1 cell line to investigate the development of Macrobrachium rosenbergii nodavirus (MrNV). Cells were incubated with viral particles and cytopathic effects were observed. De novo synthesis of viral capsid proteins was shown by immuno-fluorescence labelling and a sandwich ELISA test. Viral genomic replication was demonstrated by RT-PCR using primers specific to RNA-1 as well as by quantitative RT-PCR (RT-qPCR). Using electron microscopy, only a few empty particles were observed and attempts to isolate complete infectious particles or to re-infect healthy cells (second passage) were unsuccessful. As complete viral particles were rarely observed, it appeared that defaults in MrNV virogenesis might arise resulting in the formation of scarce and non-infectious particles. SSN-1 cells were found to be partially permissive to MrNV infection that induced cell lysis, but key elements for viral infection were lacking such as regulatory factors for gene replication or post-translational modifications.  相似文献   
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On-farm trials were conducted to assess the effects of four branch pruning levels on maize grain yield, tree growth and stem shape. The experimental plots consisted of Gmelina (Gmelina arborea R.Br.) trees planted at 1 × 10 m with maize intercropped in the 10 m-wide alleys between lines of trees. Pruning levels consisted of retaining a live crown ratio of 60–70% (T 1), 40–50% (T 2); 30–40% (T 3) and of 20–30% (T 4). At the end of the experiment, the total maize grain yield was highest under the high pruning intensity (T 4) (18.06 t ha−1) and lowest under T 1 (14.48 t ha−1). Maize grain yield under the pruning regime T 2 and T 3 were 16.08 and 17.21 t ha−1, respectively. Mean annual increment (MAI) in tree diameter was greater (5.0 cm year−1) under T 1 than those at T 4 (4.1 cm year−1). Pruning regimes T 2 and T 3 resulted in a MAI of 4.7 and 4.5 cm year−1, respectively. Financial analysis showed that maize-tree systems under T 4 were more profitable than under T 1 as long as the reduction of the average dbh at harvest were not greater than 1 cm. Pruning trees intensively also generated greater returns from labour than moderate pruning, as the greater maize grain yields under T 4 compensated for the cost of pruning and the lower timber yield. In the context of resource-poor farmers, intensive branch pruning was a practice that prolonged the period of profitable intercropping and was compatible with commercial timber production.  相似文献   
30.
A pot experiment was conducted to study the contribution of reactive phosphate rocks (RPRs) on the accumulation of Cd and Zn in 10 acid upland soils in Indonesia and shoots of Zea mays plants grown on these soils. Two types of RPR were used at a rate of 0.5 g (kg soil)–1: RPRL containing 4 mg Cd kg–1 and 224 mg Zn kg–1, and RPRH containing 69 mg Cd kg–1 and 745 mg Zn kg–1. Zea mays was harvested at 6 weeks after planting. The application of RPRH significantly increased the concentrations of Cd in the shoots. The application of this RPR also increased the amount of Cd which could be extracted by 0.5 M NH4‐acetate + 0.02 M EDTA pH 4.65 from the soils. More than 90% of the added Cd remained in the soil. As Zn is an essential element and the studied acid upland soils are Zn‐deficient, increased plant growth upon RPR application might be partly attributed to Zn present in the phosphate rock. However, more experiments are needed to confirm this hypothesis. The Cd and Zn concentrations and CEC of the soils were important soil factors influencing the concentrations of Cd and Zn in the shoots of maize plants grown on these soils.  相似文献   
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