全文获取类型
收费全文 | 618篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
林业 | 21篇 |
农学 | 11篇 |
基础科学 | 7篇 |
47篇 | |
综合类 | 142篇 |
农作物 | 8篇 |
水产渔业 | 70篇 |
畜牧兽医 | 228篇 |
园艺 | 1篇 |
植物保护 | 100篇 |
出版年
2023年 | 7篇 |
2022年 | 17篇 |
2021年 | 19篇 |
2020年 | 11篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 19篇 |
2012年 | 23篇 |
2011年 | 17篇 |
2010年 | 21篇 |
2009年 | 27篇 |
2008年 | 23篇 |
2007年 | 28篇 |
2006年 | 19篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 10篇 |
1999年 | 10篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 20篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1993年 | 20篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 15篇 |
1988年 | 7篇 |
1987年 | 13篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1976年 | 6篇 |
1959年 | 4篇 |
1958年 | 6篇 |
1954年 | 4篇 |
1947年 | 4篇 |
1945年 | 5篇 |
排序方式: 共有635条查询结果,搜索用时 15 毫秒
81.
D. B. McKEOWN DVM J. R. COCKSHUTT DVM G. D. PARTLOW PhD V. S. DE KLEER DVM 《Veterinary surgery : VS》1984,13(3):181-184
A dorsal surgical approach to the perineal area and rectum was made on 10 healthy, adult dogs. The rectococcygeal muscle was incised and the levator ani and external sphincter muscles were separated to the level of the caudal rectal nerve. All dogs were clinically normal throughout a 3 week postoperative observation period. 相似文献
82.
Summary. Several new herbicides were tested for control of weeds in broadcast-seeded flooded tropical rice. Among the new herbicides, S-(2-methyl-l-piperidylcarbonyl-methyl)- O,O -di- n -propyl dithiophosphate (C-19490), S-(2-methyl-l-piperidylcarbonyl-methyl)- O,O -di- n -propyl dithiophosphate combined with 2-(1',2'-dimethylpropylamino)-4-ethylamino-6-methylmercapto- s -triazine [C-19490/C-18898 (C-288)], and N -secondary-butyl-4-tertiary-butyl-2,6-dinitroaniline (A-820) were highly selective in controlling Echinochloa crus-galli (barnyard grass) and other annual weeds under tropical conditions. S-(4-chlorobenzyl)- N,N -diethylthiol carbamate (benthiocarb) and N -(butoxymethyl)-2-chloro-2',6'-diethylacetanilide (butachlor) continued to look promising in our experiments. Only butachlor is widely used in Asia.
Désherbage chimique des cultures tropicales de riz inorndé, seméà la volée 相似文献
Désherbage chimique des cultures tropicales de riz inorndé, seméà la volée 相似文献
83.
84.
Five methods are described, which have proved to be useful in closed chest experimental and clinical cardiovascular research in small animals. 相似文献
85.
86.
CECILIA INES ONO MORIKAWA RIE MIYAURA MARIA DE LOURDES TAPIA Y FIGUEROA ELSA LILIANA RENGIFO SALGADO YOSHIHARU FUJII 《Weed Biology and Management》2012,12(1):1-11
Peru is one of the 20 botanically extremely diverse countries in the world, with >17 000 flowering plants, of which 30% are endemic. So far, no systematic research has been conducted on the screening of the allelopathic plants. In this study, the allelopathic activity of 170 species from 61 families of Peruvian plants that were collected from the three main regions of Peru – the Costa (Pacific coastline), the Sierra (Andean mountains), and the Selva (Amazonian rainforest) – was evaluated. The allelopathic activity was determined by the Sandwich Method, which can evaluate the activity of leaf leachates. The species that were found to be highly inhibitory in this screening, under the criterion of >90% inhibition of the radicle of lettuce (Lactuca sativa) seedlings, were Aristeguietia ballii and Diplostephium foliosissimum (Asteraceae) and Spondias mombin (Anacardiaceae). All of these species are native plants from Peru. This study gives a strong clue regarding the potential of isolating potent allelochemicals from these plants in the future. 相似文献
87.
88.
不同施氮量对天然草场牧草产量影响 总被引:7,自引:0,他引:7
采用不同施氮量作用于天然草场,研究了草地施肥与牧草产量的关系,通过测定施肥试验的各项参数,确定了干草原类草场产草量和经济效益最佳的施肥方案,最佳施肥量为450kg/hm^2,同时建立了施肥量与牧草产量间的回归方程。 相似文献
89.
ANELISE REZENDE DE MORAES 《山东饲料》2013,(14):60-61
China has required a large quantity of commodities in order to keep with its economic growth path,driven by large exports,rapid urbanization and investment in fixed assets.Commodities exporter countries have benefited from China ’s immense"hunger"for commodities,especially during the 2000s.Brazil,for instance,has emerged in this scenario as one of the largest iron ore producers and exporters.However,the cooling down of the Chinese economy has brought doubts to the iron ore industry,which may remain strong in near future but one cannot claim for certain whether or not this trend will remain this positive in the long run. 相似文献
90.
研究了4个不同施牦牛粪便的处理对高寒草句植物群落多样性和生产力的短期影响。结果表明,(1)处理S1,S2和s3的植物群落盖度显著高于对照(SO)(P〈0.05),各处理的植物群落高度与对照(SO)相比都呈上升趋势,且S3与S0差异显著(P〈0.05);(2)处理S1、S2和S3的Pielou均匀度指数与sO相比逐渐下降,且S2与sO有显著差异(P〈0.05)。处理S1、s2和S3的Shannon—Wiener物种多样性指数与S0相比逐渐下降,且S2与S0差异极显著(P〈0.01)。而Simpson物种多样性指数的变化则表现为无规律性。(3)施牦牛粪便后植物群落的地上总生物量出现增加趋势,且S2,S3与s0间达到差异显著(P〈0.05)。 相似文献