全文获取类型
收费全文 | 204篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
林业 | 4篇 |
农学 | 11篇 |
基础科学 | 6篇 |
83篇 | |
综合类 | 8篇 |
农作物 | 23篇 |
水产渔业 | 21篇 |
畜牧兽医 | 42篇 |
园艺 | 3篇 |
植物保护 | 12篇 |
出版年
2023年 | 2篇 |
2021年 | 11篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 28篇 |
2017年 | 17篇 |
2016年 | 11篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 18篇 |
2012年 | 11篇 |
2011年 | 11篇 |
2010年 | 13篇 |
2009年 | 6篇 |
2008年 | 12篇 |
2007年 | 9篇 |
2006年 | 7篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有213条查询结果,搜索用时 0 毫秒
61.
The mechanism of inhibition of alpha-chymotrypsin by benzoylsalireposide (1), a phenolic glycoside isolated from Symplocos racemosa, was investigated. Lineweaver-Burk and Dixon plots and their secondary replots showed that 1 was a non-competitive inhibitor of this enzyme with the Ki value of 29.60 microM. 相似文献
62.
Syed Adeel Zafar Amjad Hameed Muhammad Amjad Nawaz Wei MA Mehmood Ali Noor Muzammil Hussain 《农业科学学报》2018,17(4):726-738
Rice, a staple cereal crop in many parts of the world, has been confronted with multiple environmental stresses including high temperature, negatively impacts the booting as well as anthesis growth stages. The situation is further complicated by the changing climatic conditions, resulting in gradual escalation of temperature as well as changing the rainfall pattern and frequency, thus raising a concern of food security worldwide. The situation can be combat by developing rice varieties with excellent genetics with improved morpho-physiological, biochemical, and molecular mechanisms, together can minimize the adverse effects of heat stress. Here, several strategies (encompassing genetic and genomic, and mechanisms involved) for mitigating the impact of high temperature on rice have been discussed. Finally, the utilization of genomic knowledge in augmenting the conventional breeding approaches have been comprehensively elaborated to develop heat tolerant germplasm. 相似文献
63.
Noshin Ilyas Fakhra Ambreen Nazima Batool Muhammad Arshad Roomina Mazhar Fatima Bibi 《Communications in Soil Science and Plant Analysis》2018,49(2):148-158
Crop rotation is a supportive management practice in which legumes greatly improve the growth and yield of subsequent cereal crops, particularly wheat. In this study, effects of mung bean (Vigna radiata)?? on the yield and quality of grains of following wheat crop were determined. An experiment was carried out with two sets of wheat (Triticum aestivum) crops: one grown following mung bean (Vigna radiata) crop and the other grown after a fallow period. Concentrations of macronutrients, sugar, protein, amino acids, and phytohormones of wheat were determined. The grain protein concentration of wheat was improved if cultivated after mung bean, and nitrogen and other macronutrients of wheat were increased significantly. In case of phytohormone contents in the wheat crop, abscisic acid concentration showed no change, but the concentrations of gibberellin increased significantly by 41% and indole acetic acid by 30% as a result of crop rotation. Sugar content in wheat cultivated after mung bean BRM-318 showed 10% increase and wheat protein content increased by 17% and 20%, respectively. The present study demonstrated that crop rotation simulated yield and improved the nutritional value of wheat grain compared to wheat which followed the fallow period. 相似文献
64.
Alireza Esmaeili Hojat Ahmadi Alireza Abbasi 《Archives of Agronomy and Soil Science》2017,63(2):161-170
Thermography is proposed to be an alternative non-destructive and rapid technique for the study and diagnosing of salt tolerance in plants. In a pot experiment, 30 cultivars of wheat (Triticum aestivum L.) were evaluated in terms of their leaf temperature and shoot growth and their ion distribution responses to NaCl salinity at two concentration levels: the control with electrical conductivity (EC) of 1 dS m?1 and salinity treatment with EC of 16 dS m?1 (150 mM). A completely randomized block design with factorial treatments was employed with three replications. The results indicated that thermography may accurately reflect the physiological status of salt-stressed wheat plants. The salt stress-based increase in leaf temperature of wheat cultivars grown at 150 mM NaCl reached 1.34°C compared to the control. According to the results obtained, it appears that thermography has the capability of discerning differences of salinity tolerance between the cultivars. Three salt-tolerant wheat cultivars, namely Roshan, Kharchia and Sholeh, had higher mean shoot dry matter (0.039 g plant?1) and higher mean ratio of leaf K+/Na+ (14.06) and showed lower increase in the mean leaf temperature (0.37°C) by thermography compared to the control. This was while nine salt-sensitive cultivars, namely Kavir, Ghods, Atrak, Parsi, Bahar, Pishtaz, Falat, Gaspard and Tajan, had lower mean plant dry matter production (0.027 g plant?1), lower mean ratio of K+/Na+ (9.49) and higher mean increases in leaf temperature (1.24°C). 相似文献
65.
Khalid Mehmood Jiu-yu Li Jun Jiang M. M. Masud Ren-kou Xu 《Journal of Soils and Sediments》2017,17(3):790-799
Purpose
We evaluated the ameliorative effects of crop straw biochars either alone or in combination with nitrate fertilizer on soil acidity and maize growth.Materials and methods
Low energy-consuming biochars were prepared from canola and peanut straws at 400 °C for 2 h. Incubation experiment was conducted to determine application rate of biochars. Afterward, maize crop was grown in pots for 85 days to investigate the effects of 1 % biochars combined with nitrate fertilizer on soil pH, exchangeable acidity, and maize growth in an Ultisol collected from Guangdong Province, China.Results and discussion
Application of 0.5, 1.0, and 1.5 % either canola straw biochar (CSB) or peanut straw biochar (PSB) increased soil pH by 0.15, 0.27, 0.34, and 0.30, 0.58, 0.83 U, respectively, after 65-day incubation. Soil pH was increased by 0.49, 0.72, 0.78, and 0.88 U when 1 % CSB or PSB was applied in combination with 100 and 200 mg N/kg of nitrate, respectively, after maize harvest in greenhouse pot experiment. These low-cost biochars when applied alone or in combination with nitrate not only reduced soil exchangeable acidity, but also increased Ca2+, Mg2+, K+, Na+, and base saturation degree of the soil. A total of 49.91 and 80.58 % decreases in exchangeable acidity were observed when 1 % CSB and PSB were incubated with the soil for 65 days, compared to pot experiment where 71.35, 78.64, 80.2, and 81.77 % reductions of exchangeable acidity were observed when 1 % CSB and PSB were applied in combination with 100 and 200 mg N/kg of nitrate, respectively. The higher contents of base cations (Ca2+, Mg2+, K+, Na+) in biochars also influenced the plant growth. The higher biomass in CSB-treated pots was attributed to the higher K content compared to PSB. The higher percent reduction in exchangeable Al3+ by applying 1 % CSB combined with 200 mg N/kg of nitrate consistently produced maximum biomass (129.65 g/pot) compared to 100 mg N/kg of nitrate and 1 % PSB combined with 100 and 200 mg N/kg of nitrate. The exchangeable Al3+ mainly responsible for exchangeable acidity was decreased with the application of biochars and nitrate fertilizer. A highly significant negative relationship was observed between soil exchangeable Al3+ and plant biomass (r 2?=?0.88, P?<?0.05).Conclusions
The biochars in combination with nitrate fertilizer are cost-effective options to effectively reduce soil acidity and improve crop growth on sustainable basis.66.
Saeed Arshad Ahsan Iqbal Sehar Nawaz Nisar Ahmed 《Frontiers of Agriculture in China》2011,5(2):129-134
The availability of a genetically diverse gene pool is vitally important in varietal development. Molecular markers are being
extensively utilized to explore the genetic diversity among native and exotic germplasm. This study was designed to reveal
the genetic diversity and patterns of relationships among the 20 accessions/genotypes representative of basmati and non-basmati
rice from the existing rice gene pool using RAPD markers. Employing RAPD, 17 decamer oligonucleotide primers directed the
amplification of 116 fragments, out of which 101 were polymorphic (87.06%) while 15 fragments were monomorphic (12.93%). Similarity
coefficients had ranged from 0.47 to 0.90. The average genetic similarity was calculated 0.68 (68%). In this study, the coarse
rice genotypes showed more polymorphism (85.84%) than the fine rice genotypes (61.76%). Genotypes were clustered into 8 distinct
groups: A, B, C, D, E, F, G, and H but two genotypes, i.e., Shadab and Kangni-27 showed divergence from all the genotypes
of the groups. Therefore, these diverse genotypes may be included in future breeding programmes. 相似文献
67.
Biosolubilization of phosphorus from rock phosphate and other P fertilizers in response to phosphate solubilizing bacteria and poultry manure in a silt loam calcareous soil
下载免费PDF全文
‘Phosphate solubilizing bacteria' (PSBs) are able to release unavailable P from native and applied P sources into plant‐available soil pool through their solubilizing and acidifying effects. The effects of three indigenous and one exotic PSBs on P solubilization from different P sources, plant biomass production, and P‐uptake efficiency of maize (Zea mays L.) were examined in an incubation and greenhouse study. For incubation study, surface (0–15 cm) soil was collected from an arable field (Inceptisols) and amended with rock phosphate (RP), single superphosphate (SSP), poultry manure (PM), and RP+PM with and without PSBs. The amended soil was incubated in the control environment at 25 ± 2°C for a total of a 100‐d period to establish relative potential rate of P solubilization of added P sources. A complementary greenhouse experiment was conducted in pots by growing maize as a test crop. Growth characteristics, P‐uptake, and P‐utilization efficiency (PUE) were determined. Phosphate solubilizing bacteria generated a solubilization effect on different P sources by releasing more P into plant‐available soil pool, i.e., 14.0–18.3 µg g?1 in RP, 5.0–9.9 µg g?1 in SSP, 1.4–4.4 µg g?1 in PM, and 4.5–7.8 µg g?1 in RP+PM compared to their sole application without PSBs. The available P from inorganic SSP declined continuously from the mineral pool (after day 30) and at the end 40% of applied P was unaccounted for. However, P losses were reduced to 28 and 27% when PSBs (PSB1 and PSB3) were applied with superphosphate treatments. In the absence of PSBs, the recoveries of applied P (in soil) from RP, SSP, PM and RP+PM were 4, 25, 9, and 12%, respectively, those had been increased to 14, 30, 12 and 15% in the presence of PSBs. Similarly, the plant biomass in RP+PSBs treatments compared to the RP without PSBs increased between 12–30% in first sampling (30 DAG) and 13–30% in the second sampling (60 DAG). The P utilization efficiency (PUE) in plants supplemented with PSBs was 20–73% higher compared to those without PSBs. The detection of oxalic and gluconic acids in culture medium treated with PSBs (7.8–25.0 and 25–90 mg L?1, respectively) confirmed the production of organic acids by the indigenous bacterial isolates. This study indicate that low P recovery both in plant and soil can likely be improved by using indigenous PSBs and organic amendment poultry manure, which allowed a more efficient capture of P released due to P solubilization. 相似文献
68.
We report for the first time the capability of four-leaf clover (Marsilea quadrifolia), a wetland plant which grows rooted in soil, in efficiently treating sewage. The use of M. quadrifolia was made possible because of the special attributes of the SHEFROL® (SHEet Flow ROot Level) bioreactor in which it was employed. This bioreactor enables the use of free-floating aquatic plants as well as terrestrial and rooted-in-soil wetland plants by hydroponics. The plants are staked in narrow channels to enable them to support each other while sewage is made to flow rapidly as a sheet of wastewater at a level that covers only the plant roots (hence the name). It was seen that M. quadrifolia was able to treat sewage of strength varying in the chemical oxygen demand (COD) range of 600–1800 mg/L to the extent of >?80% at a hydraulic retention time (HRT) of just 4.5 h. There was a near total removal of biological oxygen demand and suspended solids while total Kjeldahl nitrogen, soluble phosphorous, and heavy metal zinc were also substantially removed. The macrophyte was equally effective when used indoors under artificial lighting, as well as when used outdoors. 相似文献
69.
The aim of this study was to examine the effect of the nitrification inhibitor nitrapyrin on the fate and recovery of fertilizer nitrogen (N) and on N mineralization from soil organic sources. Intact soil cores were collected from a grassland field. Diammonium phosphate (DAP) and urea were applied as N sources. Cores were equilibrated at –5 kPa matric potential and incubated at 20 °C for 42 to 56 days. Changes in NH4+‐N, accumulation of NO3–‐N, apparent recovery of applied N, and emission of N2O (acetylene was used to block N2O reductase) were examined during the study. A significant increase in NH4+‐N released through mineralization was recorded when nitrapyrin was added to the control soil without N fertilizer application. In the soils to which N was added either as urea or DAP, 50–90 % of the applied N disappeared from the NH4+‐N pool. Some of this N (8–16 %) accumulated as NO3–‐N, while a small proportion of N (1 %) escaped as N2O. Addition of nitrapyrin resulted in a decrease and delay of NH4+‐N disappearance, accumulation of much lower soil NO3–‐N contents, a substantial reduction in N2O emissions, and a 30–40 % increase in the apparent recovery of added N. The study indicates that N recovery can be increased by using the nitrification inhibitor nitrapyrin in grassland soils at moisture condition close to field capacity. 相似文献
70.
Md. Aminur Rahman Muhammad Zaher Kazi Md. Azimuddin Selina Yeasmine Md. Mominuzzaman Khan Aziz Arshad 《Aquaculture Research》2013,44(7):1132-1139
The fingerling‐rearing experiment of the threatened catfish, Mystus cavasius was carried out at different stocking densities in earthen nursery ponds. Twelve‐day‐old fry were stocked at 200 000 ha?1 in treatment‐1 (T1), 250 000 ha?1 in treatment‐2 (T2) and 300 000 ha?1 in treatment‐3 (T3) respectively. The mean length and weight of fry at stocking was 1.24 ± 0.25 cm and 0.11 ± 0.04 g respectively. Fry in all the experimental ponds were supplemented with SABINCO nursery feed for the first 14 days and starter‐I feed for days 15–56. The physico‐chemical parameters and plankton population of pond water were within the suitable level for fish culture. Growth in terms of final weight, final length, weight gain, length gain and specific growth rate and survival of fingerlings were significantly higher in T1 than those in T2 and T3. Feed conversion rate was significantly lower in T1 followed by T2 and T3 in that order. Significantly higher number of fingerlings was produced in T3 than that in T2 and T1. Even then, consistently higher net benefits were obtained from T1 than those from T3 and T2. Among the treatments evaluated, 200 000 fry ha?1 was the best stocking density considering the highest growth, production and net benefits of fingerlings of M. cavasius in nursery ponds. 相似文献