全文获取类型
收费全文 | 9676篇 |
免费 | 469篇 |
国内免费 | 14篇 |
专业分类
林业 | 597篇 |
农学 | 242篇 |
基础科学 | 84篇 |
1627篇 | |
综合类 | 1700篇 |
农作物 | 389篇 |
水产渔业 | 879篇 |
畜牧兽医 | 3552篇 |
园艺 | 290篇 |
植物保护 | 799篇 |
出版年
2024年 | 19篇 |
2023年 | 62篇 |
2022年 | 90篇 |
2021年 | 161篇 |
2020年 | 221篇 |
2019年 | 213篇 |
2018年 | 217篇 |
2017年 | 227篇 |
2016年 | 215篇 |
2015年 | 194篇 |
2014年 | 263篇 |
2013年 | 469篇 |
2012年 | 561篇 |
2011年 | 722篇 |
2010年 | 377篇 |
2009年 | 363篇 |
2008年 | 647篇 |
2007年 | 641篇 |
2006年 | 605篇 |
2005年 | 588篇 |
2004年 | 622篇 |
2003年 | 588篇 |
2002年 | 524篇 |
2001年 | 108篇 |
2000年 | 99篇 |
1999年 | 100篇 |
1998年 | 89篇 |
1997年 | 71篇 |
1996年 | 67篇 |
1995年 | 68篇 |
1994年 | 64篇 |
1993年 | 53篇 |
1992年 | 67篇 |
1991年 | 60篇 |
1990年 | 63篇 |
1989年 | 60篇 |
1988年 | 46篇 |
1987年 | 50篇 |
1986年 | 39篇 |
1985年 | 38篇 |
1984年 | 35篇 |
1983年 | 44篇 |
1982年 | 28篇 |
1981年 | 28篇 |
1980年 | 31篇 |
1979年 | 28篇 |
1978年 | 24篇 |
1976年 | 25篇 |
1975年 | 24篇 |
1974年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Mitchell D Stamm Tiffany M Heng‐Moss Frederick P Baxendale Blair D Siegfried Roch E Gaussoin Daniel D Snow David A Cassada 《Pest management science》2013,69(2):285-291
BACKGROUND: Neonicotinoid insecticides are generally efficacious against many turfgrass pests, including several important phloem‐feeding insects. However, inconsistencies in control of western chinch bugs, Blissus occiduus, have been documented in field efficacy studies. This research investigated the efficacy of three neonicotinoid insecticides (clothianidin, imidacloprid and thiamethoxam) against B. occiduus in buffalograss under field conditions and detected statistically significant differences in B. occiduus numbers among treatments. A subsequent study documented the relative quantity and degradation rate of these insecticides in buffalograss systemic leaf tissues, using HPLC. RESULTS: Neonicotinoid insecticides initially provided significant reductions in B. occiduus numbers, but mortality diminished over the course of the field studies. Furthermore, while all three neonicotinoids were present in the assayed buffalograss leaf tissues, imidacloprid concentrations were significantly higher than those of clothianidin and thiamethoxam. Over the course of the 28 day study, thiamethoxam concentrations declined 700‐fold, whereas imidacloprid and clothianidin declined only 70‐fold and 60‐fold respectively. CONCLUSIONS: Field studies continued to verify inconsistencies in B. occiduus control with neonicotinoid insecticides. This is the first study to document the relative concentrations of topically applied neonicotinoid insecticides in buffalograss systemic leaf tissues. Copyright © 2012 Society of Chemical Industry 相似文献
42.
43.
44.
45.
Francisco A Macías Nuria Chinchilla Elena Arroyo Rosa M Varela José MG Molinillo David Marín 《Pest management science》2010,66(10):1137-1147
BACKGROUND: Fifteen novel derivatives of D‐DIBOA, including aromatic ring modifications and the addition of side chains in positions C‐2 and N‐4, had previously been synthesised and their phytotoxicity on standard target species (STS) evaluated. This strategy combined steric, electronic, solubility and lipophilicity requirements to achieve the maximum phytotoxic activity. An evaluation of the bioactivity of these compounds on the systems Oryza sativa–Echinochloa crus‐galli and Triticum aestivum–Avena fatua is reported here. RESULTS: All compounds showed inhibition profiles on the two species Echinochloa crus‐galli (L.) Beauv. and Avena fatua L. The most marked effects were caused by 6F‐4Pr‐D‐DIBOA, 6F‐4Val‐D‐DIBOA, 6Cl‐4Pr‐D‐DIBOA and 6Cl‐4Val‐D‐DIBOA. The IC50 values for the systems Echinochloa crus‐galli–Oryza sativa and Avena fatua–Triticum aestivum for all compounds were compared. The compound that showed the greatest selectivity for the system Echinochloa crus‐galli–Oryza sativa was 8Cl‐4Pr‐D‐DIBOA, which was 15 times more selective than the commercial herbicide propanil (Cotanil‐35). With regard to the system Avena fatua–Triticum aestivum, the compounds that showed the highest selectivities were 8Cl‐4Val‐D‐DIBOA and 6F‐4Pr‐D‐DIBOA. The results obtained for 6F‐4Pr‐D‐DIBOA are of great interest because of the high phytotoxicity to Avena fatua (IC50 = 6 µM , r2 = 0.9616). CONCLUSION: The in vitro phytotoxicity profiles and selectivities shown by the compounds described here make them candidates for higher‐level studies. 8Cl‐4Pr‐D‐DIBOA for the system Echinochloa crus‐galli‐Oryza sativa and 6F‐4Pr‐D‐DIBOA for Avena fatua‐Triticum aestivum were the most interesting compounds. Copyright © 2010 Society of Chemical Industry 相似文献
46.
Galina Lebedev Fauzi Abo‐Moch Guy Gafni David Ben‐Yakir Murad Ghanim 《Pest management science》2013,69(2):274-277
BACKGROUND: The onion thrips, Thrips tabaci Lindeman, is a major pest of several crop plants in the genus Allium, such as onions, garlic and chives. In Israel, these crops are grown in open fields and in protected housing. This thrips is usually controlled by the application of chemical insecticides. In recent years, spinosad, emamectin benzoate and carbosulfan have been the major insecticides used for the control of the onion thrips. In the last 4 years, growers of chives and green onion from several regions of Israel have reported a significant decrease in the efficacy of insecticides used to control the onion thrips. RESULTS: The susceptibility of 14 populations of the onion thrips, collected mainly from chives between the years 2007 and 2011, to spinosad, emamectin benzoate and carbosulfan was tested using a laboratory bioassay. The majority of the populations showed significant levels of resistance to at least one of the insecticides. LC50 values calculated for two of the studied populations showed that the resistance factor for spinosad compared with the susceptible population is 21 393, for carbosulfan 54 and for emamectin benzoate 36. Only two populations, collected from organic farms, were susceptible to the insecticides tested. CONCLUSION: This is the first report of a high resistance level to spinosad, the major insecticide used to control the onion thrips. Resistance cases to spinosad were associated with failures to control the pest. Populations resistant to spinosad also had partial or complete resistance to other insecticides used for controlling the onion thrips. Copyright © 2012 Society of Chemical Industry 相似文献
47.
Waseem Akbar Anilkumar Gowda Jeffrey E Ahrens Jason W Stelzer Robert S Brown Scott L Bollman John T Greenplate Jeffrey Gore Angus L Catchot Gus Lorenz Scott D Stewart David L Kerns Jeremy K Greene Michael D Toews David A Herbert Dominic D Reisig Gregory A Sword Peter C Ellsworth Larry D Godfrey Thomas L Clark 《Pest management science》2019,75(3):867-877
48.
F2 screen,inheritance and cross‐resistance of field‐derived Vip3A resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) collected from Louisiana,USA
下载免费PDF全文
![点击此处可从《Pest management science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
49.
50.
David Bowles 《中国禽业导刊》2008,25(8):8-9
两个世纪以来,欧盟一直在推进动物福利,在欧盟公众眼中,食品安全和质量与农场动物福利之间存在必然联系。面对科学证据和公众对于改进的期待,欧盟的反应一直是通过立法程序去淘汰最坏的系统和惯例。 相似文献