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   172篇
  免费   9篇
林业   26篇
农学   45篇
  49篇
综合类   10篇
农作物   12篇
水产渔业   5篇
畜牧兽医   17篇
园艺   3篇
植物保护   14篇
  2023年   2篇
  2022年   1篇
  2021年   5篇
  2020年   5篇
  2019年   5篇
  2018年   7篇
  2017年   5篇
  2016年   7篇
  2015年   5篇
  2014年   7篇
  2013年   9篇
  2012年   10篇
  2011年   11篇
  2010年   6篇
  2009年   8篇
  2008年   16篇
  2007年   8篇
  2006年   7篇
  2005年   8篇
  2004年   7篇
  2003年   10篇
  2002年   5篇
  2001年   3篇
  2000年   3篇
  1999年   2篇
  1998年   1篇
  1996年   3篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   4篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1981年   1篇
  1978年   1篇
  1964年   1篇
排序方式: 共有181条查询结果,搜索用时 15 毫秒
21.
22.
Introgression lines (ILs) of groundnut with enhanced resistance to rust and late leaf spot (LLS) recorded increased pod and haulm yield in multilocation testing. Marker‐assisted backcrossing (MABC) approach was used to introgress a genomic region containing a major QTL that explains >80% of phenotypic variance (PV) for rust resistance and 67.98% PV for LLS resistance. ILs in the genetic background of TAG 24, ICGV 91114 and JL 24 were evaluated for two seasons to select 20 best ILs based on resistance, productivity parameters and maturity duration. Multilocation evaluation of the selected ILs was conducted in three locations including disease hot spots. Background genotype, environment and genotype × environment interactions are important for expression of resistance governed by the QTL region. Six best ILs namely ICGV 13192, ICGV 13193, ICGV 13200, ICGV 13206, ICGV 13228 and ICGV 13229 were selected with 39–79% higher mean pod yield and 25–89% higher mean haulm yield over their respective recurrent parents. Pod yield increase was contributed by increase in seed mass and number of pods per plant.  相似文献   
23.
Induced resistance was studied in three sorghum genotypes (IS2205, ICSV1 and ICSV700) against Chilo partellus (Swinhoe) (Lepidoptera; Pyralidae) infestation and jasmonic acid (JA) and salicylic acid (SA) application. The activity of plant defensive enzymes [peroxidase (POD), polyphenol oxidase (PPO), superoxide dismutase (SOD), and catalase (CAT)], and the amounts of total phenols, hydrogen peroxide (H2O2), malondialdehyde (MDA), and proteins were recorded at 6 days after infestation. The induction of enzyme activities and the amounts of secondary metabolites varied among the genotypes and treatments. The genotype IS2205 showed a stronger effect than that of ICSV1 or ICSV 700. Treatment with JA followed by insect infestation induced greater levels of enzymes and secondary metabolites. The results suggest that JA induces greater levels of resistance components in sorghum plants against insect pests. Thus, pretreatment of plants with elicitors including JA and SA could provide a greater opportunity for plant defense against herbivores.  相似文献   
24.
Use of diverse germplasm is a key factor which allows high level of resolution due to extensive recombination in the history. Therefore, population used in association mapping should posses as many phenotypes as possible. One of the methods to obtain most of the phenotypes is to construct the core collection. The ICRISAT foxtail millet core collection consisting of 155 accessions was genotyped using 72 simple sequence repeat (SSR) markers to investigate the genetic diversity, population structure and linkage disequilibrium (LD). A high degree of molecular diversity among the accessions was found, with an average of 16.69 alleles per locus. STRUCTURE analyses classify the accessions into four subpopulations (SP) based on SSR allelic diversity. The Neighbor joining clustering and the principal coordinate analysis were in accordance with the racial classification. The distribution of molecular genetic variation among and within the four SP and three races showed high degree of variability within each group, and low level of genetic distance (GD) among the groups. LD decay of <40 cM of GD in foxtail millet core collection was observed, which suggests that it could be possible to achieve resolution down to the 40 cM level. From this investigation, it is evident that the foxtail millet core collection developed at ICRISAT is very diverse and could be a valuable resource for trait association mapping, crop breeding and germplasm management.  相似文献   
25.
The compensation point of bidirectional NOx fluxes of plants is often determined in chamber measurements by varying the NOx concentration and searching for the point where the net flux is zero. We hypothesized that the compensation point can vary with changing conditions so much that one constant value is not sufficiently accurate. The compensation point for NOx fluxes of Scots pine was analysed with a model describing the NOx consumption and production processes. Consumption was assumed to occur via the stomata and on needle surfaces, with the rate depending on ambient concentration and degree of stomatal opening. Production was assumed to occur on the needle surfaces depending on solar UV-A irradiance. We used NOy flux data measured with two gas-exchange chambers in southern Finland to parameterize the model. The estimated compensation points increased with increasing UV-A irradiance and decreased with increasing stomatal conductance. With open stomata, it varied several ppb even under field conditions.  相似文献   
26.
Fatty acid composition and C18:2:C18:3 of soybean seed and sprout is important for soy-industries to manufacture quality products. Six soybean varieties were analyzed by gas chromatography to determine fatty acid composition and linoleic to linolenic acid ratio (C18:2:C18:3) in seed, sprout, and their structural parts. In the case of whole seed and its structural parts, significant variation in fatty acid composition and C18:2:C18:3 were observed between varieties except palmitic acid (C16:0), while all the parameters were significantly different for seed parts. Significant interactions of variety with seed parts were observed for oleic acid (C18:1), C18:2 and C18:2:C18:3. The highest saturated fatty acid, C18:1 and polyunsaturated fatty acid were recorded in seed coat, cotyledon, and seed axis, respectively. The lowest C18:2:C18:3 was found in seed axis. In the case of sprout study, variety had significant effect on all the parameters observed for whole sprout, cotyledon, root, and except C18:3 for hypocotyl. Culture days had significant effect on C16:0, C18:2 and C18:3 in whole sprouts, while only on C18:3 and C18:2:C18:3 in cotyledon. For hypocotyl, culture days had significant effect on C18:1, C18:2 and C18:2:C18:3, however, C16:0, C18:1, C18:3, and C18:2:C18:3 were significantly different in root. In sprout, days and variety interacted significantly for C16:0, C18:3 and C18:2:C18:3, and C18:1, C18:2, C18:3, and C18:2:C18:3, respectively for whole, cotyledon, and root. The significantly lowest C18:2:C18:3 (1.1) was observed in hypocotyl and root of Hwangkeumkong in 5 days. Knowledge of fatty acid composition and C18:2:C18:3 of seed, sprout, and their parts could be applicable for oil and other soy-food industries to make quality products.  相似文献   
27.
28.
Objectives: To report the repair of tibial diaphyseal fractures in 2 calves using a circular external skeletal fixator (CEF). Study Design: Clinical report. Animals: Crossbred calves (n=2; age: 6 months; weight: 55 and 60 kg). Methods: Mid‐diaphyseal tibial fractures were repaired by the use of a 4‐ring CEF (made of aluminum rings with 2 mm K‐wires) alone in 1 calf and in combination with hemicerclage wiring in 1 calf. Results: Both calves had good weight bearing with moderate lameness postoperatively. Fracture healing occurred by day 60 in 1 calf and by day 30 in calf 2. The CEF was well maintained and tolerated by both calves through fracture healing. Joint mobility and limb usage improved gradually after CEF removal. Conclusions: CEF provided a stable fixation of tibial fractures and healing within 60 days and functional recovery within 90 days. Clinical Relevance: CEF can be safely and successfully used for the management of selected tibial fractures in calves.  相似文献   
29.
Seeds of thirteen genotypes of cauliflower, four of turnip and seven of radish were analysed for oil content and fatty acid composition. Turnip and radish had higher oil content as compared to cauliflower. Oleic, linoleic + eicosenoic and erucic acids were the major fatty acids in the oils of these seeds. Levels of erucic acid were in the order of radish < turnip < cauliflower. Compared to cauliflower and turnip seeds, radish seeds contained higher amounts of palmitic, oleic, and linolenic + eicosenoic acids and lower amounts of linoleic and erucic acids.  相似文献   
30.
A series of monoazo disperse dyes based on 2-amino-4-phenylthiazole was prepared using variousN,N-dialkylaniline derivatives as the coupling component. The dyes were characterized by IR spectral studies, visible absorption spectroscopy and elemental analysis. The dyeing performance of these dyes was assessed on cellulose triacetate and nylon fibers. These dyes were found to give a wide range of colour shades varying from bright red to royal blue with very good depth, brightness and levelness on fibers. The dyed fibers showed good to very good light fastness and very good to excellent fastness to washing, perspiration, rubbing and sublimation. The dyebath exhaustion and fixation on the fibers were found to be very good.  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