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   52篇
  免费   0篇
林业   8篇
农学   9篇
  12篇
农作物   1篇
水产渔业   9篇
畜牧兽医   7篇
植物保护   6篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   3篇
  2019年   1篇
  2018年   4篇
  2017年   2篇
  2016年   1篇
  2014年   1篇
  2013年   4篇
  2011年   6篇
  2009年   7篇
  2008年   4篇
  2007年   3篇
  2006年   1篇
  2005年   2篇
  2003年   2篇
  2001年   2篇
  1999年   1篇
  1994年   1篇
排序方式: 共有52条查询结果,搜索用时 817 毫秒
31.
The behavior of metals in sediments after their disposal to land has important implications for the environmental management. The sediment from the Carska Bara (Serbia) was polluted with adequate metal salts in order to reach severe contamination based on the pseudo-total metal content of Pb, Cd, Ni, Zn, Cu, and Cr according to the corresponding Dutch standards and Canadian guidelines. The toxicity and fate of the metal in sediment depend on its chemical form, and therefore, quantification of the different forms of a metal is more meaningful than the estimation of its total concentration. In this study, fractionation of metals in sediment has been investigated to determine its speciation and ecotoxic potential, as well as evaluation of metal potential toxicity based on the simultaneously extracted metals (SEMs) and acid volatile sulfides (AVSs) analysis at the beginning of the experiment and after 5?weeks of sediment aging. The investigations suggest that Cd, Pb, and Zn have a tendency to associate with labile fraction, the most mobile and most dangerous fraction for the environment. Risk assessment code revealed their high risk. Copper and chromium showed low to medium risk to the aquatic environment. Nickel showed no risk to the aquatic environment. This was the case at the beginning and after 5?weeks of aging. Aging yielded an increased mobility of all metals based on the increased proportion in mobile fractions. The ??[SEM i ]/[AVS] ratio was found to be >1 both at the beginning and after 5?weeks of aging, with the ratio showing an increase with time. This ratio indicates the potential availability/toxicity and, according to the US EPA criteria, the samples belong to the group with probable negative effect. If particular metals are considered, only the ??[SEM i ]/[AVS] ratio for zinc was >1 at the beginning. After 5?weeks, the ratio was >1 for zinc, lead, and copper. Comparison of the results of sequential extraction and the results of SEM and AVS analysis showed good agreement for lead and zinc.  相似文献   
32.
Salt tolerance in soybean [Glycine max (L.) Merr.] is controlled by major quantitative trait loci (QTL) or single gene(s). Among soybean germplasm, wild soybean plant introduction PI 483463 was reported to have a single dominant gene for salt tolerance. The objective of this study was to genetically map the QTL in a recombinant inbred line (RIL) population derived from a cross between PI 483463 and Hutcheson. Simple sequence repeat (SSR) markers and universal soybean single nucleotide polymorphism (SNP) panel (the USLP 1.0) were utilized for molecular genotyping. The RILs were phenotyped in two independent tests in a greenhouse using a 1–5 scale visual rating method. The results showed that the salt tolerant QTL in PI 483463 was mapped to chromosome 3 in a genomic region between the Satt255 and BARC-038333-10036 markers. The favorable allele inherited from PI 483463 conferred tolerance to salinity and had an additive effect on reducing leaf scorch. A subset of 66 iso-lines was developed from the F3 families of the same cross and was used for genetic confirmation of the QTL. The integration of recombination events and the salt reaction data indicate that the QTL is located in the region of approximately a 658 kb segment between SSR03_1335 at nucleotide 40,505,992 and SSR03_1359 at nucleotide 41,164,735 on chromosome 3. This narrow region can facilitate further genomic research for salt tolerance in soybean including cloning salt tolerance genes.  相似文献   
33.
Indonesia is one of the largest teak timber producers in the world. The Javanese State Forest Company has been a major producer of teak timber in Indonesia; however, log production decreased drastically due to severe illegal logging after the collapse of Suharto regime. In contrast, small-scale private forests (PFs) owned by local farmers have expanded and are expected to be a new source of teak timber. Long rotation is a critical factor in producing a larger diameter log with a higher heartwood proportion. However, harvest timing in PFs is traditionally decided based on individual farmers’ needs even if trees are still young and of small diameter. Therefore, traditional harvesting is an obstacle to producing high-quality teak timber. The objectives of this study are to (1) identify the household economies and PF management styles of local farmers, (2) characterize the local farmers who conduct traditional harvesting, and (3) suggest key considerations for PF policymaking. Key informant interviews and semi-structured interviews with local farmers were conducted in three villages in Gunungkidul district, Yogyakarta Special Region. The study identified the household economies, the ownership and management structures, and the traditional harvesting in PFs in the three villages, and reaffirmed diversity and complexity of PFs. It appears that PF management is influenced by topographic and socioeconomic conditions and differs widely across villages. Therefore, it is important to consider the diversity and complexity of PFs in PF policymaking.  相似文献   
34.
After years of unsustainable logging, dry deciduous dipterocarp forest (DDDF) has become poor in timber stocks and has been converted to industrial crops such as rubber. The objectives of this study were to assess teak (Tectona grandis L.f.) tree establishment under degraded DDDF conditions and to determine factors that influence the suitability of teak as a forest enrichment tree species. A set of 64 experimental plots of 4 900 m2 each was set up and observed for 4–5 years for testing enrichment planting with teak under various combinations of two groups of factors: ecological conditions and forest status. Weighted, non-linear, multivariate regression models were used to detect key factors that influenced the suitability of teak. The results showed that at the age of 4 years the average dominant tree height (defined as 20% of the tallest trees in the experimental plot) reached 11.2, 7.8, 5.3 and 3.8 m for very good, good, average and poor suitability levels, respectively. Survival rates of planted teak from average to very good suitability levels were over 90%. Six key factors that affected the suitability of teak were waterlogging during the rainy season, altitude, stand volume of the degraded DDDF, soil type, percentage of sand and concentration of P2O5 in the soil. Under the extreme ecological and environmental conditions of the DDDF, enrichment planting with teak gave promising results.  相似文献   
35.
Twenty-four kinds of water extracts derived from 22 plants that are traditionally used for the treatment of malaria on Java Island, Indonesia, were screened for their antibabesial and antimalarial activities. Among the extracts, 8 extracts displayed strong antimalarial activity, with an inhibition range from 89.6 to 100%, and 15 showed strong antibabesial activity, with an inhibition range from 84.2 to 98.1%. The extracts of Achillea millefolium, Baeckea frutenscens, Brucea javanica, Curcuma xanthorrhiza, Strychnos lucida and Swietenia macrophylla showed both strong antibabesial and antimalarial activities. The antimalarial activities paralleled the antibabesial activities, but the converse was not true.  相似文献   
36.
Journal of Crop Science and Biotechnology - The low frequency of plantlet regenerates from the somatic embryogenesis (SE) callus in sugarcane becomes a problem to produce its seed. Plant growth...  相似文献   
37.
Journal of Crop Science and Biotechnology - The transgenic sugarcane overexpressing SoSPS1 gene increased sugar content which may alter the root exudation that interact with soil rhizosphere...  相似文献   
38.
Journal of Crop Science and Biotechnology - The role of genetic diversity in crop germplasm is an important concept within genetic conservation. In this research, 43 accessions were analyzed at the...  相似文献   
39.
Benzyl isothiocyanate (BITC), a compound found in cruciferous vegetables, is an effective chemopreventive agent. The objective of this study was to develop nanoemulsion formulations for the oral delivery of BITC. Optimized oil-in-water BITC nanoemulsions were prepared by a spontaneous self-nanoemulsification method and a homogenization-sonication method. Both nanoemulsions entrapped high amounts of BITC (15-17 mg/mL), with low polydispersity and good colloidal stability. The BITC nanoemulsions showed enhanced solubility and dissolution compared to pure BITC. These formulations markedly increased the apical to basolateral transport of BITC in Caco-2 cell monolayers. The apparent permeability values were 3.6 × 10(-6) cm/s for pure BITC and (1.1-1.3) × 10(-5) cm/s for BITC nanoemulsions. The nanoemulsions were easily taken up by human cancer cells A549 and SKOV-3 and inhibited tumor growth in vitro. This work shows for the first time that BITC can be formulated into nanoemulsions and may show promise in enhancing absorption and bioavailability.  相似文献   
40.
Phytophthora infestans is endemic to Indonesia and can infect potato crops at any stage in the growing season. Little is known about P. infestans populations in Indonesia. The objectives of this study were first to identify the genotypes causing late blight in the main potato-growing regions on Java in Indonesia, and secondly to examine genotypic diversity in the P. infestans populations in those regions. Samples were collected on FTA cards (n = 140) or in tubers (n = 6) from 15 locations in nine regencies over four years (2016–2019). Microsatellite analysis revealed that late blight outbreaks in these regencies were caused by EU_2_A1 and other genotypes that are unique to Indonesia. Eighty percent of the samples that amplified with CAPS markers were the A1 mating type. Cultures of six isolates were determined to be the A1 mating type based on the pairing test, and of these, two isolates were intermediate and four were sensitive to metalaxyl-M (mefenoxam). The mode of reproduction of the P. infestans population on Java, Indonesia, was found to be clonal. However, as the sample size in this study was small, more isolates need to be tested to confirm this. Microsatellite analysis revealed that 90% of Indonesian samples had trisomic loci. A high number of multilocus genotypes (MLGs) were found in all nine regencies (131 MLGs out of 146 samples). Results indicate that there is ongoing polyploidization in these populations due to a high mutation rate and no selection pressure from the susceptible potato hosts that are being grown in Indonesia.  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