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131.
Wetland protection is a complex issue. In the executive system of wetland preservation, the central government is the main body of policy formulation and implementation. Although China has taken many steps to protect wetlands, there are still some institutional, legal and policy problems in the area of wetland protection. This article presents an analysis of these factors. First, the authors state and analyze the major legal and management problems currently hampering wetland protection in China. Then the authors believe that in the future, new problems of wetland protection will arise. Given the following three major aspects of wetland protection in China: i.e., the policy, law and management systems, this article provides some relevant suggestions in the area of policies and management.  相似文献   
132.
To clarify the influencing factors of liquefaction of wood in phenol using phosphoric acid as a catalyst and get its liquefaction technology, a study on the liquefaction technology of Chinese fir (Cunninghamia lanceolata) and poplar (triploid Populus tomentosa Carr) under different conditions was conducted. The results indicate that the residue rate decreases with the increase of liquefaction temperature, liquefaction time, catalyst content or liquid ratio. It is also found that the optimum condition of liquefaction for poplar is estimated as: the reaction temperature of 180 ℃, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio)of 4.5 and catalyst content of 8%, and 4.2% residue rate could be obtained. Under the processing parameters of temperature 180 ℃, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio) of 4 and catalyst content of 10%, the residue rate of Chinese fir can reach 5.6%.  相似文献   
133.
    
Combined application of synthetic nitrogen (N) fertilizers and organic materials can enhance soil quality, but little is known about the distribution of fertilizer N among different soil fractions after crop harvest. A pot experiment using 15N tracer was employed to address this question with three treatments, i.e., labeled urea-only (15NU), labeled urea + rice straw (15NU-S) and labeled rice straw + urea (15NS-U) applied to a Ferallic Cambisol (1:1 type soil clay mineral) and a Calcaric Fluvisol (2:1 clay mineral). Soil microbial biomass N, fixed ammonium (fixed NH4+), exchangeable ammonium and soil organic N fractions by hydrolysis (6 N HCl) and their isotope abundance were determined after the rice harvest. Soil newly formed N in urea + straw (U-S) treatments (15NU-S, 15NS-U) was the sum of labeled urea-N in 15NU-S and labeled straw-N in 15NS-U. Compared with 15NU, U-S significantly (P < 0.05) increased the content and percentage of newly formed total soil N, acid insoluble N, amino acid N, and hydrolysable unknown N in both soils. In U-S treatment, straw amendment significantly (P < 0.05) reduced the content and percentage of newly formed fixed-NH4+-N in Fluvisol as compared with 15NU treatments. Soil microbes contributed to the larger percentage of newly formed amino acid N (P < 0.01) in Cambisol as compared with Fluvisol. Fertilizer N in various soil fractions was therefore strongly affected by clay mineral type and microbes after the combined application of organic materials and synthetic N fertilizer.  相似文献   
134.
分子标记在甘蓝遗传育种中的应用   总被引:3,自引:0,他引:3  
本文综述了分子标记在甘蓝遗传育种中应用的几个方面:1、分子标记遗传图谱的建立;2、亲缘关系和遗传多样性的研究;3、基因定位;4、品种纯度鉴定;5、分子标记辅助选择。  相似文献   
135.
以优良粳稻恢复系K1863为主体亲本,以国际水稻分子育种品种资源为供体亲本通过杂交并回交,获得了100多个K1863回交改造后代群体。对其中部分K1863回交改造后代进行了表型性状鉴定,初步表明被鉴定的多数K1863回交后代获得了主体亲本K1863对粳稻不育系的恢复能力,在回交后代中产生了稻瘟病抗性、耐盐性优于主体亲本K1863的材料,而且部分K1863回交改造后代的综合经济性状也优于主体亲本K1863。从而说明,利用国际水稻分子育种品种资源,通过大量回交,不仅可以在保留主体亲本的重要性状、保持与主体亲本性状相似性的同时,获得一些主体亲本本身不具有的有利性状,并选育出综合经济性状优于主体亲本的回交后代,因此通过本方法获得的回交后代材料具有重要的育种利用价值。本文还探讨了对这些K1863回交改造后代进行进一步利用改造的途径。  相似文献   
136.
区域稻田土壤碳储量的空间分布特征   总被引:2,自引:0,他引:2       下载免费PDF全文
基于土壤类型法估算重庆市巴南区稻田土壤有机碳储量及其空间分布特征,结果表明:研究区稻田土壤有机碳总储量约为6.48×106 t,平均土壤有机碳密度为8.31 kg m-2,略高于全国平均水平。重庆市巴南区稻田0-20 cm土壤有机碳密度介于1.73~3.70 kg m-2 之间,剖面土壤有机碳密度介于5.13~14.07 kg m-2之间。0-20 cm和100 cm土壤有机碳储量分别为1.18×106 t和4.39×106 t,0-20 cm土壤有机碳储量为0-100 cm碳储量的27.50%,说明碳储量主要富集在表层土壤。土壤有机碳密度呈带状分布,且具有高度的不均匀性,同类土壤具有相似的有机碳蓄积量。  相似文献   
137.
    
Two experiments were conducted to investigate the effect of inland water salinity on growth performance, feed conversion efficiency and intestinal enzyme activity in grey mullet. In experiment I, a 90 day monoculture of grey mullet at different salinity levels (0, 10, 15, 20 and 25%) was carried out. The fingerlings were stocked at 5000 per hectare and fed on a supplementary diet at 5% BW d–1. This Study revealed that fish growth mean body weight (90.5 ± 4.5 g) and mean length (21.6 ± 0.4 cm), SGR (4.70%) and growth per day (0.99 g d–1) were significantly (p < 0.05) enhanced in fish maintained at 10% salinity in comparison with other treatments. Nutrient levels, phytoplankton population, NPP and chlorophyll a all decreased with an increase in salinity (>10%). In addition, zooplankton populations increased with an increase in the salinity level. Most of the other hydrochemical characteristics remained at optimal levels in all other treatments. Fish weight gain showed a significant positive correlation with productivity indicating parameters viz. alkalinity (r = 0.53), turbidity (r = 0.62), NPP (r = 0.75) and chlorophyll a (r = 0.46), clearly revealing that fish growth is also related to the trophic status of the ponds. In the second experiment (Experiment II), mullet fry were exposed to five different salinity levels (10, 15, 20, 25 and 30%) and maintained for 70 days in the laboratory. Significantly (p < 0.05) high growth, (SGR and per cent increase in body weight), feed conversion efficiency and intestinal enzyme activity were observed in the group maintained at 10 salinity in comparison with other groups maintained at similar salinity levels. Carcass composition, musc1e and liver glycogen levels were also significantly (p < 0.05) affected by salinity changes.  相似文献   
138.
番茄叶霉病抗性基因Cf-5的CAPS标记建立   总被引:9,自引:0,他引:9  
番茄是世界上最主要的蔬菜作物之一,叶霉病(Cladosporium fulvum Cooke)的发生和蔓延使保护地番茄生产受到严重影响,培育抗叶霉病的番茄品种是控制该病害最经济有效的方法。本研究根据Cf-5的基因序列设计特异扩增引物,以7个含有不同叶霉病抗病基因的品种为试材,扩增Cf-5基因2558~3523bp之间的单拷贝片段,7个材料均获得了约0.96Kb的特异扩增片段。用限制性内切酶TaqⅠ对该片段进行酶切,含Cf-5基因的材料产生了一条256bp的特异片段,而不含Cf—5基因的材料产生一条225bp的特异片段。从而建立了Cf-5基因的共显性CAPS标记。这一研究结果为Cf-5基因的分子标记辅助育种奠定了良好基础。  相似文献   
139.
Primary cilia (PC) were demonstrated for the first time in fish endothelial, epithelial and fibroblast cell lines through immunofluorescence staining with the monoclonal antibody, 6-11B-1, against acetylated α-tubulin. The study was carried out with eight recently developed cell lines from the walleye, Sander vitreus (Mitchill). These were three fibroblast-like cell lines, WE-cfin11f, WE-skin11f and WE-liver3 from, respectively, the caudal fin, skin and liver, and three epithelial-like cell lines, WE-cfin11e, WE-spleen6 and WErpe from, respectively, the caudal fin, spleen and retina. Also, endothelial-like WEBA from the bulbus arteriosus and glial-like WE-brain5 from the brain were used. Immunocytochemistry revealed strong staining for acetylated α-tubulin in mitotic spindles and midbodies for all cell lines, and in PC for all cell lines except WE-skin11f. Staining of cytoplasmic microtubules (fibrils) was absent in three cell lines, including WEBA, but present in the others, especially WE-skin11f, which might have obscured PC detection in these cells. Tubacin, an inhibitor of histone deacetylase 6, induced cytoplasmic fibrils in WEBA and the intensity of their staining in WE-cfin11f. These results suggest that the cell lines might differ in their deacetylase activities, making them useful for studying this tubulin modification in teleosts, as well as for studying PC.  相似文献   
140.
草甘膦生物抗性和生物降解及其转基因研究   总被引:24,自引:0,他引:24  
草甘膦(N—phosphonomethyl—glycine,glyphosate)毒性作用机理是竞争性抑制莽草酸途径中的5-烯醇丙酮莽草酸-3-磷酸合成酶(5-enolpyruvyl—shikimate—3—phosphate synthase,简称EPSP合成酶)的活性。EPSP合成酶是植物和微生物体内芳香族氨基酸(包括色氨酸、酪氨酸、苯丙氨酸等)生物合成过程中的一个关键酶。该酶由aroA基因编码。抗草甘膦微生物或植物中EPSP合成酶基因的核苷酸序列在相同或相近位点发生了突变。将编码EPSP合成酶的突变基因导入大豆和烟草等作物中,均能获得转基因的抗草甘膦作物。草甘膦的生物降解途径主要有两条,C-N断裂生成氨甲基磷酸(AMPA)或C-P键断裂生成肌氨酸(sarcosine),然后两种中间代谢物进一步代谢为磷酸、甘氨酸和二氧化碳等。  相似文献   
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