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   42篇
  免费   7篇
  国内免费   2篇
林业   3篇
农学   6篇
  4篇
综合类   17篇
农作物   6篇
水产渔业   4篇
畜牧兽医   1篇
植物保护   10篇
  2024年   1篇
  2023年   1篇
  2021年   2篇
  2020年   1篇
  2019年   3篇
  2018年   1篇
  2017年   4篇
  2016年   1篇
  2015年   4篇
  2014年   5篇
  2013年   2篇
  2012年   1篇
  2011年   4篇
  2010年   2篇
  2009年   2篇
  2006年   1篇
  2005年   7篇
  2004年   2篇
  2002年   1篇
  2001年   1篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
排序方式: 共有51条查询结果,搜索用时 15 毫秒
1.
随着人们对粮食安全问题的重视,政府部门不断加强对粮食安全的监测工作。针对粮食生产、加工、储运过程中的化学污染物安全性问题,研究粮食污染物快速监测技术,研究污染物免疫分析方法通过利用抗原、抗体的特异性反应来检测农药含量,设计并筛选吡虫啉、多溴联苯醚、功夫菊酯、氰戊菊酯4种半抗原,制备相关高特异性的抗体,分析吡虫啉、多溴联苯醚、功夫菊酯与气相色谱法(GC)相比,稻谷、大米、玉米样品通过相关性分析均高度相关,操作简便、快速。  相似文献   
2.
二苯醚是一种重要的农药中间体,通过W/O微乳法,制备出形貌均一的球状纳米CuI,并应用于催化C-O交叉偶联反应中,在温和的反应条件下,合成了具有优良产率的二苯醚类化合物,该方法可在今后的农药合成中应用。  相似文献   
3.
茚酮肟醚衍生物的合成与生物活性   总被引:2,自引:0,他引:2  
通过傅-克反应及环化、肟化、成醚等反应,合成了10个未见文献报道的茚酮肟醚类化合物,其结构均经1H NMR、IR、LC/MS及元素分析确证。初步生物活性测试结果表明,所合成的化合物具有明显的杀菌活性或杀虫活性,如在100 mg/L时,化合物 V1 对小麦白粉病菌Erysiphe graminis 的抑制率为 95.6%, V5 对粘虫Mythimna separata的致死率为100%。  相似文献   
4.
采用未成熟SD大鼠肝细胞微粒体为试验材料,以2,3,7,8-四氯-二苯基-并-二哑噁英(2,3,7,8- tetrachlorobenzo-p-dioxin,TCDD)作为参照,利用甲氧基-异酚噁脱甲基酶(methoxyresorufin-O- demethylase,MROD)竞争性抑制动力学和荧光光谱法分析法,测定了5种多溴联苯(polybrominated diphenyl ethers,PBDEs)对7-甲氧基-异酚噁唑脱甲基反应的影响,间接研究了这些PBDEs对CYP1A2 的竞争性抑制作用。结果表明,和TCDD相比,PBDEs对MROD活性的抑制作用较弱,亦即对CYP1A2的 竞争性抑制作用较弱。  相似文献   
5.
The normal method to determine the trace brominated flame retardants such as polybrominated biphenyls (PBBs) and polybrominated diphenylethers (PBDEs) contained in the electronic and electrical products is gas chromatography/mass spectrometry (GC/MS). However, the method is based on the determinations of the persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), and polychlorinated naphthalene (PCNs) etc. The interferences of those compounds are inevitable. Therefore, in order to overcome this problem, two methods e.g. 1) The combination use of gas chromatography negative ion chemical ionization mass spectrometry (GC-NICI-MS) and gas chromatography-electron impact-mass spectrometry (GC-EI-MS) is employed, 2) a matrix solid-phase dispersion (MSPD) method with YMC ODS-C18 as carrier is developed. The result show that, by the former method, the brominated isomers or ramifications are distinguished remarkably from other halogen compounds because that anion fragment retention peaks of [Br]-, [HBr2]- and molecule chain fragment retention peaks of [M+2]+,[M+4]+,[M+6]+,[M+8]+ are observed simultaneously, and thus the selectivity to determine bromine-containing retardant flames is greatly improved. Using the latter method, the gas chromatographic peaks of multiple polychlorinated biphenyls and polybrominated diphenylethers can be efficiently separated. Thus provides a project to solve interferences of POPs in brominated flame retardants’ determinations. The standard addition experimental results of 10 kinds of BDEs/PCBs belonging to 8 sorts of electronic and electrical equipment show this method has a high precision and reliability due to 60%~98% recovery and <9.5% relative error, which meet the needs regulated by the IEC Commission. It provides a technical support for electronic and eletrical industries in China to further comply with RoHS directive.  相似文献   
6.
茶园土壤和茶树叶片农药残留量规律的探讨   总被引:1,自引:0,他引:1  
对福建省108个有代表性的茶园有机氯农药六六六(BHC)、滴滴涕(DDT)残留量现状进行调查,共采茶树鲜叶、土样和背景土样344个.分析结果表明:(1)BHC在茶树及土壤中分布均匀,且主要残留于土壤中,但均已自然降解到较低水平;DDT主要残留于树体,茶树与土壤中的分布有明显差异.BHC污染来自以往施药所致,DDT污染主要是80年代引起,DDT残留量高于BHC.(2)名贵品种种植园土壤DDT残留量比一般品种园高,但其叶片农药残留量却比一般品种园低.(3)各品种茶树叶片及其种植土壤农药残留量均与树龄、海拔高度、土壤深度等有一定相关  相似文献   
7.
Synthesis and insecticidal activities of novel oxime ether pyrethroids   总被引:5,自引:0,他引:5  
Liu A  Ou X  Huang M  Wang X  Liu X  Wang Y  Chen C  Yao J 《Pest management science》2005,61(2):166-170
A series of novel 2-methylthio-3'/4'-substituted acetophenone oxime O-ethers were synthesized by the reaction of the corresponding acetophenone oximes with halides of pyrethroid alcohols in the presence of sodium hydroxide and phase-transfer catalysis or with triethyl quaternary ammonium salts of halides of pyrethroid alcohols in the presence of sodium hydroxide. These compounds showed notable insecticidal activity against Homopteran and Lepidopteran pests. 2-Methylthio-4'-fluoroacetophenone oxime O-[(2-methylbiphenyl-3-yl)methyl] ether was more effective than the commercial insecticides chlorfenapyr and fenvalerate.  相似文献   
8.
联苯双酯抗大鼠四氯化碳肝损伤的实验研究   总被引:4,自引:0,他引:4  
目的:通过观察联苯双酯(DDB)对四氯化碳(CC l4)所致大鼠急性肝损伤的防治作用,结合文献复习,对DDB的临床应用价值进行再评价。方法:24只大鼠随机分为3组:正常对照组、肝损伤模型组(简称模型组)、DDB治疗组(简称DDB组),每组8只。模型组和DDB组分别用CC l4造成大鼠急性实验性肝损伤,DDB组加用DDB滴丸(5 m g.kg-1)灌胃,每天1次,共14 d,正常对照组和模型组大鼠每天用生理盐水(20 mL.k-g 1)灌胃。实验结束后,检测各组大鼠血清丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(A ST)的含量,并取肝脏做病理组织检查。结果:DDB组血清ALT、A ST水平较模型组明显降低(P<0.01)。DDB组大鼠肝组织切片中肝细胞脂肪变性、炎细胞浸润均较模型组明显减轻,且肝组织中无明显纤维增生。结论:DDB能显著降低CC l4所致急性肝损伤大鼠血清ALT、A ST水平,对CC l4所致大鼠的肝损伤具有显著的防治作用。  相似文献   
9.
The purpose of the research was to identify the phenolic and flavonoid compounds of seven different traditional pigmented whole rice cultivars grown in the temperate regions of Kashmir so as to study their relationship with in vitro antioxidant capacities. The completely pigmented rice cultivars were found to have higher phenolic, flavonoid, anthocyanin contents and exhibited higher antioxidant capacities than the light colored and sparely colored rice cultivars. A total of 40 compounds had been identified in the analyzed rice cultivars that were found to be distributed in 6 major categories with 6-phenolics, 6-flavonoids, 11-hydroxycinnamic acid derivatives, 7-hydroxybenzoic acid derivatives, 3-anthocyanins and 7-flavonoid glucosides of different flavonoid compounds. Among the free and bound fractions for each cultivars the light and sparsely colored depicted higher content of phenolics and in vitro antioxidant properties in bound faction, while the completely pigmented cultivars showed higher antioxidant properties in free fractions. The anthocyanins quercetin-3-O-galactoside, cyanidin-3-O-rutinoside and pelargonidin-3-O-diglucoside had been identified by LC-MS existing in the free fractions of the analyzed rice cultivars whereas, the free fraction of acetone + H2O possessed higher percentage of phenolic compounds as compared to methanolic extracts and bound fractions. The black colored cultivars possessed higher DPPH scavenging activity and lipid peroxidation inhibition.  相似文献   
10.
 【目的】合成N-苯氧苯基取代的α-氨基酸衍生物,并测定化合物的生物活性及其在植物体内的传导性。【方法】通过氨基二苯醚类化合物分别与乙醛酸乙酯和丙酮酸乙酯缩合,形成2个希夫碱化合物(Ia-Ib),并经NaBH4还原,合成了5个N-苯氧苯基取代的α-氨基酸衍生物,以二苯醚类除草剂三氟羧草醚为对照药剂,测定化合物对水稻幼苗根、芽的室内生物活性;以空心莲子草为试验材料,以苯氧苯基甘氨酸乙酯(IIa)为试验药剂,喷雾处理空心莲子草后采用HPLC法测定该化合物在植株根中的含量来判断其传导性。【结果】化合物Ⅰa和Ⅱa对水稻幼苗的根、芽的生长均具有一定的抑制作用,化合物Ⅱb在低浓度下对水稻芽具有促进生长的作用,化合物Ⅱc和Ⅱd在低浓度下对水稻幼苗的根具有促进生长的作用;供试化合物在光照条件下的生物活性均比在黑暗条件下高;利用化合物Ⅱa 300 mg•L-1的药液喷雾处理空心莲子草地上部分12 h后,在其根部检测到目标化合物(IIa)含量为8.67 mg•kg-1 FW。【结论】二苯醚类化合物衍生出氨基酸基团后,所得衍生物既保留了二苯醚类除草剂的需光性除草活性特点,又增加了经由植物韧皮部向根部的传导性。  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