全文获取类型
收费全文 | 135篇 |
免费 | 4篇 |
专业分类
林业 | 20篇 |
农学 | 11篇 |
基础科学 | 4篇 |
32篇 | |
综合类 | 8篇 |
农作物 | 15篇 |
水产渔业 | 18篇 |
畜牧兽医 | 21篇 |
植物保护 | 10篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 14篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 10篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有139条查询结果,搜索用时 31 毫秒
131.
Khouloud M. Barakat Heba S. El-Sayed Yousry M. Gohar 《International Aquatic Research》2016,8(2):179-189
Antimicrobial nanoparticle therapy was proposed as an alternative strategy to reduce the use of antibiotics in larval-rearing systems. Antibacterial potential of the prepared squilla chitosan–silver nanoparticles and its protective effect on Dicentrarchus labrax (sea bass) larvae in the early stages were studied against Vibrio angularium. Different concentrations of squilla chitosan (Csq) and squilla chitosan–silver nanoparticles (Csq–AgNps) (1, 2, 5, 10, and 20 %) were, in vitro, tested against V.anguillarum and expressed as a role of Log10 mean. Sea bass larvae were treated using: 10 % Csq and 5 % Csq–AgNps as effective inhibitory concentrations against the pathogen either encapsulated during the feeding regime or added directly to the model system via the water from the onset of 4 weeks. The long-term administration of Csq–AgNps through enriched food for both non-infected and infected systems had survival % of 74.5 ± 1.5 and 72.5 ± 2.5, respectively. Larval clinical observations using Csq–AgNps were studied compared with the two controls. The current study found that 5 % encapsulated Csq–AgNps was enough to suppress infection and considered as an alternative to antibiotics in controlling virulent fish pathogens. 相似文献
132.
Iron (Fe) and zinc (Zn) are essential nutrients for plant growth and development. Therefore, a pot experiment was conducted to examine the role of Zn and Fe on vegetative growth, photosynthetic pigments, soluble sugars, soluble protein, nitrate reductase (NR), ascorbate peroxidase (APX), catalase (CAT), minerals content, amino acid composition fraction, isozymes, and protein electrophoresis in faba bean plants foliar sprayed with FeSO4 and ZnSO4. The results revealed that foliar spray with 1 or 3 g/L of FeSO4 and ZnSO4 significantly increased all the abovementioned parameters compared to control plants. The activity of esterase increased with increasing concentration of Fe and Zn as compared to control plants. The most pronounced increase was found in plants treated with 3 g/L ZnSO4. Three bands of peroxidase isozyme were exhibited with different densities and intensities in all treatments. Three types of modification were observed in the protein patterns of faba bean leaves. Some protein bands disappeared, while other increased and synthesis of a new set of proteins was induced. It could be concluded that foliar spray with the two concentrations (1 or 3 g/L) of ZnSO4 and FeSO4 helped faba bean plants to overcome the deficiency in these minerals by producing antioxidant enzymes. Improved faba bean growth through adequate Fe and Zn foliar spray is likely a promising strategy to improve Vicia faba plants. 相似文献
133.
134.
135.
In the present study, depriving chickens of foraging material was shown to induce stress. The impact of this type of stress on the immune response was compared with feeding of corticosterone (1.5 mg per bird per day), a hormone known to be immunosuppressive and to be the major stress hormone of chickens. Corticosterone feeding induced stress as revealed by higher heterophil/lymphocyte (H/L) ratios, longer tonic immobility (TI) reaction, reduced body weight gain and reduced egg production. Blood corticosterone levels were increased. Corticosterone feeding decreased the antibody response to tetanus toxoid and SRBC, DTH to PPD from Mycobacterium tuberculosis and the inflammatory response to PHA. Housing chickens on slats also induced chronic stress, as evidenced by increased H/L ratios, prolonged TI duration and decreased egg production. Corticosterone levels were slightly but not significantly enhanced. This novel form of chronic stress strongly suppressed humoral and cellular immune responses as evidenced by lower antibody titers to sheep red blood cells (SRBC) and tetanus toxoid (TT) decreased DTH reaction to PPD and inflammatory reaction to PHA in the skin. In contrast, the antibody response to human serum albumin (HSA) was neither influenced by corticosterone feeding nor by keeping the birds on slats. Even the combination of corticosterone feeding and housing the birds on slats did not significantly impair antibody responses to HSA. In conclusion, the present study showed that chronic stress induced by depriving the birds of foraging material led to a similar impairment of humoral and cell-mediated immunity as did feeding with corticosterone. More importantly, it showed for the first time that depending on the antigen tested, there are stress-resistant and stress-susceptible antigen responses. 相似文献
136.
Highly resistant, resistant and susceptible rice cultivars were tested in the greenhouse to determine their effect on Sogatella furcifera (Horváth) populations. The highly resistant cultivar IR2035-117-3, with resistance genes Wbph 1 and Wbph 2, caused the highest S. furcifera mortality. When the effects of varietal resistance and predation were combined the increase in mortality due to predators was additive. The spider Lycosa pseudoannulata Boes. et Str., mirid bug Cytorhinus lividipennis Reuter, ladybird beetle Harmonia octomaculata (F.) and rove beetle Paederus fuscipes Curt. were effective predators of S. furcifera and generally caused 30% mortality on the various cultivars. Results indicate that the integration of varietal resistance and predation would provide effective control of S. furcifera populations under field conditions. 相似文献
137.
138.
Khurram Bashir Nasir Mahmood Khan Sultana Rasheed Muhammad Salim 《Paddy and Water Environment》2007,5(2):73-81
Pakistan is well known for its basmati rice with long grain and aroma, as well as for non-basmati indica varieties; however
average yield is lower as compared with other countries. Besides, cultural practices, the main reason for low productivity
in Pakistan is that, local varieties are susceptible to different biotic and abiotic factors like insect pests, diseases,
drought, and salinity. Different approaches have been undertaken in Pakistan to tackle these problems through traditional
breeding of selection and crossing, mutation breeding, somaclonal variation as well as plant transformation studies in recent
past. For variety development, the most successful examples arose from traditional breeding that produced famous basmati varieties
like Basmati 370, Basmati 385 and Super basmati, and non-basmati varieties such as IRRI-6, DR-82, DR-83, DR-92, Swat-I and
Swat-II, which earn a significant share of foreign exchange every year. Six varieties have also been developed through mutation
breeding, and one through exploitation of somaclonal variation but their contribution to the national economy is not significant.
On the other hand, no variety has been registered as commercial by plant transformation groups. This review discusses the
problems and prospects of rice breeding with special emphasis on basmati rice in Pakistan particularly in Pakistani Punjab
(a major producing area), as well as focuses on future research programs. 相似文献
139.
Citric acid (CA), a widely used eco-friendly electrolyte, can be employed as an agent for enhancing toxic metal (TM) removal from contaminated dredged sediment using electrokinetic (EK) technology. In this study, dredged harbor sediments co-contaminated by TMs were subjected to enhanced EK treatment using a mixture of chelating agent (CA) and surfactant as an additive in the processing fluids. Several control conditions that may influence the efficiency of TM removal were tested, including open/closed sediment chamber orifices, electric potential gradients (0.5, 1.0, and 1.5 V cm-1), and electrolyte surfactant. Tween 20 (4 mmol L-1) was used as a surfactant within the electrolyte to investigate the extent of TM removal in sediment with high organic matter content. The results showed that an open orifice led to a greater electro-osmotic flow (EOF) with moderate TM removal. In contrast, a closed orifice with a nonionic surfactant electrolyte allowed the highest removal of TMs from the matrix. Moreover, increasing the electric potential gradient led to a higher EOF under the open orifice condition, but no significant increase in TM removal was observed owing to a higher accumulation of TMs in the middle of the matrix, caused by the opposite direction of EOF and electro-migration of metal-citrate complexes. 相似文献