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   1044篇
  免费   80篇
  国内免费   126篇
林业   25篇
农学   57篇
  18篇
综合类   375篇
农作物   93篇
水产渔业   46篇
畜牧兽医   337篇
园艺   14篇
植物保护   285篇
  2024年   5篇
  2023年   42篇
  2022年   52篇
  2021年   55篇
  2020年   35篇
  2019年   47篇
  2018年   34篇
  2017年   49篇
  2016年   60篇
  2015年   55篇
  2014年   66篇
  2013年   66篇
  2012年   71篇
  2011年   91篇
  2010年   65篇
  2009年   79篇
  2008年   68篇
  2007年   70篇
  2006年   46篇
  2005年   39篇
  2004年   33篇
  2003年   21篇
  2002年   16篇
  2001年   23篇
  2000年   11篇
  1999年   7篇
  1998年   7篇
  1997年   6篇
  1996年   6篇
  1995年   8篇
  1994年   4篇
  1993年   2篇
  1991年   1篇
  1990年   3篇
  1989年   5篇
  1988年   2篇
排序方式: 共有1250条查询结果,搜索用时 296 毫秒
101.
本试验用新药蚕用脓病清,蚕用抗菌素九0一九和常用氯霉素分别给家蚕添食,结果表明,经添食上述药物后,蚕期病死蚕数,死笼率明显低于对照区,虫蛹统一生命率显高于对照区。说明三种蚕药对蚕病的发生均起到较好的防治作用,但以添食氯霉素的效果最好。  相似文献   
102.
兽用喹诺酮类药物发展动态   总被引:5,自引:2,他引:3  
综述了兽用喹诺酮类药物—包括国内外已上市的、尚在开发中的以及人用药可转化为兽用药三个部分的品种,并对在我国尚未上市的兽用喹诺酮类药物的药理作用及用途作了简介。  相似文献   
103.
配制三种浓度的血虫净、盐酸土霉素、中药制剂及其两两相互组合三个复方共 1 2种药物方剂组 ,对猪附红细胞体病的病例进行治疗试验。结果表明 ,血虫净 中药制剂组疗效最佳 ,经治疗 6d后红细胞感染率显著低于其他组( P <0 .0 5或 P <0 .0 1 ) ,且死亡率为零 ,治疗愈率达到 1 0 0 % ;中药制剂组红细胞感染率、死亡率显著高于其余组 ( P <0 .0 5或 P <0 .0 1 ) ,而治愈率、有效率低于其余组。证明中草药与西药合用有协同增效作用。  相似文献   
104.
Objective: To summarize typical clinical signs, characterize the anticipated course of action, and give treatment recommendations for ibuprofen ingestion in ferrets.
Design: Retrospective study
Patients: Records of 43 cases of ibuprofen ingestion in ferrets that were reported between January 1996-March 2000, to the ASPCA Animal Poison Control Center (APCC).
Measurements and Main Results: Twenty-seven (93.1%) ferrets that had ingested ibuprofen developed neurologic signs, such as depression, coma, ataxia, recumbency, tremors, and weakness. In addition, 16 cases (55.2%) had one or more GI effects including anorexia, vomiting, retching or gagging, diarrhea, and melena. Polydipsia, polyuria, dysuria, renal failure, weight loss, shallow breathing, metabolic acidosis, dehydration, and hypothermia were also reported. Death was reported in 4 cases. The lowest dose associated with death was 220 mg/kg.
Conclusion: Data in this study indicate that clinical signs of ibuprofen toxicosis in ferrets are more severe than those expected at similar dosages in dogs. The reason for this difference is poorly understood since the pathophysiology of ibuprofen is relatively unknown in ferrets. The onset of clinical signs appeared to occurr soon after ingestion and the toxic effects in ferrets typically involve the CNS, GI and renal systems. Treatment for ibuprofen toxicosis in the ferret includes stabilization, gastrointestinal decontamination, fluid diuresis, GI protection, and supportive care.(J Vet Emerg Crit Care 2001; 11(1):53–59)  相似文献   
105.
Pristimerin and celastrol isolated from the roots of Celastrus hypoleucus (Oliv) Warb f argutior Loes exhibited inhibitory effects against diverse phytopathogenic fungi. Pristimerin and celastrol were found to inhibit the mycelial growth of Rhizoctonia solani Kuhn and Glomerella cingulata (Stonem) Spauld & Schrenk in vitro by 83.6 and 62.6%, respectively, at 10 microg ml(-1). Pristimerin showed good preventive effect (96.7% at 100 microg ml(-1)) and curative effect (66.5% at 100 microg ml(-1)) against wheat powdery mildew in vivo. For celastrol, the preventive and curative effects against wheat powdery mildew were 80.5 and 45.4%, respectively, at 100 microg ml(-1).  相似文献   
106.
A new acidic derivative of the fungicide fenpiclonil was synthesized containing a methyl group on the alpha-position of the carboxyl function of N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole. The phloem mobility of the resulting N-(1-carboxyethyl)-3-cyano-4-(2,3-dichlorophenyl)pyrrole was comparable with that of the former compound, but was higher at external pH 5.0. Unlike the derivatives previously synthesized, it was comparable with fenpiclonil in its fungicidal activity against the pathogenic fungus Eutypa lata.  相似文献   
107.
In Uganda, control of vector-borne diseases is mainly in form of vector control, and chemotherapy. There have been reports that acaricides are being misused in the pastoralist systems in Uganda. This is because of the belief by scientists that intensive application of acaricide is uneconomical and unsustainable particularly in the indigenous cattle. The objective of this study was to investigate the strategies, rationale and effectiveness of vector-borne disease control by pastoralists. To systematically carry out these investigations, a combination of qualitative and quantitative research methods was used, in both the collection and the analysis of data. Cattle keepers were found to control tick-borne diseases (TBDs) mainly through spraying, in contrast with the control of trypanosomosis for which the main method of control was by chemotherapy. The majority of herders applied acaricides weekly and used an acaricide of lower strength than recommended by the manufacturers. They used very little acaricide wash, and spraying was preferred to dipping. Furthermore, pastoralists either treated sick animals themselves or did nothing at all, rather than using veterinary personnel. Oxytetracycline (OTC) was the drug commonly used in the treatment of TBDs. Nevertheless, although pastoralists may not have been following recommended practices in their control of ticks and tick-borne diseases, they were neither wasteful nor uneconomical and their methods appeared to be effective. Trypanosomosis was not a problem either in Sembabule or Mbarara district. Those who used trypanocides were found to use more drugs than were necessary.  相似文献   
108.
 拮抗球胞链霉菌AM6代谢产物田间试验结果表明,以含有AM6拮抗物质的液剂喷雾烟草叶片,可有效防治烟草赤星病。其防效随液剂中拮抗物质的含量的增加而升高,以100倍稀释防效最好,田间防效可达80.3%;施用次数2次为佳,平均防效达64.9%,病害发生严重时,可增施1次。同时,试验过程中发现含有AM6拮抗物质的液剂对烟草无明显药害。  相似文献   
109.
A series of derivatives of the phenylpyrrole fungicide fenpiclonil was synthesized in which a carboxyl group was present at various sites of this non-phloem-mobile molecule. Using the Kleier model, all these acidic analogues were predicted to be moderately phloem-mobile, especially the N-substituted derivatives. One of these latter molecules, N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole, exhibited some fungicidal activity on the pathogenic fungus Eutypa lata, and was then tested as a phloem-mobile pesticide in the Ricinus system. The compound was indeed mobile in the sieve tubes and was not degraded to fenpiclonil in the phloem sap under our experimental conditions. Its concentration in the sap was closely correlated to the percentage of the undissociated form of the molecule in the external medium, and was similar under acidic conditions (external pH 4.6-5.0) to that of the herbicide glyphosate.  相似文献   
110.
Ageratum conyzoides L. is an annual herb in the tropics and subtropics whose extracts are known to possess pharmacological and biocidal activity. We report on the bioactivity of a secondary metabolite (a chromene) isolated from the shoots ofA. conyzoides against some plant pathogenic fungi. Organic solvent extracts from the shoots were tested for antifungal activity against the plant pathogenic fungiRhizoctonia solani, Sclerotium rolfsii, Botryodiplodia theobromae, Phomopsis theae andFusarium species growingin vitro on potato dextrose agar medium. The cruden-hexane extract completely inhibited the growth ofR. solani andS. rolfsii. Then-hexane extract was chromatographed over a column of silica gel followed by activity-guided fractionation to give an antifungal principle. Structure elucidation by detailed analysis of1H,13C NMR and mass spectroscopy identified the active compound as precocene II. The growth ofR. solani andS. rolfsii was completely inhibited by precocene II at a concentration of 80–100 ppm. The sclerotia ofR. solani andS. rolfsii were also completely suppressed by 150 ppm of precocene II. Sub-culture of these inhibited fungi onto precocene II-free medium restored growth of the fungus, indicating that precocene II is fungistatic. Crude or refined extracts fromA. conyzoides offer the possibility of biocontrol of plant pathogenic fungi. http://www.phytoparasitica.org posting Feb. 11, 2004.  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