全文获取类型
收费全文 | 1709篇 |
免费 | 132篇 |
学科分类
农业科学 | 1841篇 |
出版年
2024年 | 8篇 |
2023年 | 35篇 |
2022年 | 19篇 |
2021年 | 72篇 |
2020年 | 87篇 |
2019年 | 81篇 |
2018年 | 56篇 |
2017年 | 57篇 |
2016年 | 69篇 |
2015年 | 64篇 |
2014年 | 67篇 |
2013年 | 70篇 |
2012年 | 142篇 |
2011年 | 151篇 |
2010年 | 77篇 |
2009年 | 70篇 |
2008年 | 127篇 |
2007年 | 112篇 |
2006年 | 93篇 |
2005年 | 74篇 |
2004年 | 68篇 |
2003年 | 72篇 |
2002年 | 69篇 |
2001年 | 6篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1841条查询结果,搜索用时 20 毫秒
31.
32.
Anna Bassols José Angel Robles-Guirado Laura Arroyo Lourdes Soler Natalia García Raquel Pato Raquel Peña Yolanda Saco Ramon Armengol Fermín Lampreave María A. Alava Francesca Canalias Matilde Piñeiro 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2023,52(Z1):64-74
33.
34.
Finnegan Laura Viejou Rebecca MacNearney Doug Pigeon Karine E. Stenhouse Gordon B. 《Landscape Ecology》2021,36(9):2619-2635
Landscape Ecology - Anthropogenic disturbance alters animal movements. Large mammals require vast areas to meet their needs, and they encounter anthropogenic disturbances frequently during daily... 相似文献
35.
Larval traits of the Caribbean amphidromous goby Sicydium punctatum (Gobioidei: Sicydiinae) in Guadeloupe 下载免费PDF全文
Léa Lejeune Hélène Tabouret Laura Taillebois Dominique Monti Philippe Keith 《Ecology of Freshwater Fish》2016,25(2):272-280
Amphidromous fish are the biggest contributor to the diversity of fish communities in river systems of Caribbean islands. Among them, Sicydium punctatum Perugia, 1896, which is endemic to the West Indies, represents the vast majority of fish in these rivers. The otolith microstructure and the biometry of S. punctatum postlarvae from Guadeloupe were investigated to explore the dispersal modalities of this species through an appreciation of the growth pattern, the pelagic larval duration (PLD) and the size‐at‐recruitment. The study was made on one cohort of 83 recruited postlarvae, fished at the Capesterre River's mouth on 2 November 2011. The mean (±SD) size‐at‐recruitment of the postlarvae was 24.6 ± 1.3 mm (range of 20.5–28.1 mm, n = 83). We found a mean (±SD) PLD of 72.2 ± 10.5 days (range of 54–101.5 days, n = 67). The growth rate estimated from the otolith increments showed a globally decreasing pattern during the marine larval phase. Growth rates at the beginning of the larval stage were significantly different between hatching periods, suggesting a relation between the hatching period and the growth rate in S. punctatum. This study adds on to the general understanding of the life cycle of S. punctatum in Guadeloupe that will help implement strategies to manage amphidromous fish populations in the Caribbean region. 相似文献
36.
George Eng Stephen P. Coddington Laura L. Stockton Alexander D. W. Acholonu 《Pest management science》1989,26(2):117-121
The effect of organotin compounds on the growth of Ceratocystis ulmi, the causative agent of Dutch elm disease, was studied in shake culture. Triphenyltin, (C6H5)3SnX, tricyclohexyltin, (C6H11)3SnX, and tributyltin, (C4H9)3SnX, compounds were all effective in the inhibition of C. ulmi in vitro. The anionic group, X, did not play a major role in the inhibitory activities of these compounds, suggesting that the species involved in the inhibition is R3Sn+ or the hydrated cation. 相似文献
37.
38.
Evaluation of an air-filtration system for preventing aerosol transmission of Porcine reproductive and respiratory syndrome virus 下载免费PDF全文
Scott Dee Laura Batista John Deen Carlos Pijoan 《Canadian journal of veterinary research》2005,69(4):293-298
The purpose of this study was to evaluate the ability of a commercial air-filtration system to reduce aerosol transmission of Porcine reproductive and respiratory syndrome virus (PRRSV). The system consisted of a pre-filter and 2 filters with EU8 and EU13 ratings. In each of 4 trials, 5 PRRSV-infected donor pigs and 1 naive recipient pig (each 25 kg) were housed in opposing chambers connected by a 1.3-m-long duct. The system filtered air entering 1 recipient-pig chamber (filtered facility) from the donor-pig chamber but not a 2nd recipient-pig chamber (nonfiltered facility). The donor pigs had been experimentally infected with PRRSV MN-184, an isolate previously documented to be shed at a high frequency in contagious aerosols. On days 3 to 7 after infection of the donors, the 2 groups were housed in their respective chambers for 6 h and then in separate facilities, where samples were collected for testing by polymerase chain reaction and enzyme-linked immunosorbent assay over 14 d. Aerosol transmission was observed in 6 of the 20 replicates in the nonfiltered facility, whereas all pigs remained PRRSV-negative in the filtered facility; the difference was significant at P < 0.01. Thus, under the conditions of this study, the air-filtration system evaluated appeared to be highly effective at reducing aerosol transmission of PRRSV. 相似文献
39.
40.
Moore DA Atwill ER Kirk JH Brahmbhatt D Herrera Alonso L Hou L Singer MD Miller TD 《Journal of the American Veterinary Medical Association》2003,223(6):839-845
OBJECTIVE: To evaluate the effect of daily oral administration of decoquinate to neonatal calves experimentally challenged with various numbers of Cryptosporidium parvum oocysts. DESIGN: Clinical trial. ANIMALS: 75 calves. PROCEDURE: Calves were purchased from a commercial dairy during a 5-week period. Calves were housed in individual hutches and fed milk replacer with or without decoquinate (2 mg/kg [0.9 mg/lb per day]). Calves were randomly assigned to treatment and 1 of 5 challenge groups (0, 50, 100, 1000, or 10,000 C. parvum oocysts in 60 mL of saline [0.9% NaCl] solution administered p.o. on the day after arrival). Calves were maintained in the study for as long as 28 days. Calves were clinically assessed for diarrhea and dehydration. Fecal samples were submitted for oocyst enumeration 3 times each week. RESULTS: Treatment did not affect number of days to first watery feces (diarrhea), number of days to first oocyst shedding, or duration of diarrhea or oocyst shedding. Duration of oocyst shedding was significantly associated with challenge dose of oocysts administered to calves and number of days to first oocyst shedding. Duration of diarrhea and number of days to first oocyst shedding were significantly associated with week of arrival and number of days to first watery diarrhea. CONCLUSIONS AND CLINICAL RELEVANCE: Daily treatment with decoquinate at the dosage used in this study did not affect oocyst shedding or clinical signs associated with cryptosporidiosis. However, there was an indication that if the number of oocysts calves received could be reduced, then the duration of oocyst shedding and, hence, environmental loading of C. parvum oocysts could be reduced. 相似文献