全文获取类型
收费全文 | 118篇 |
免费 | 9篇 |
专业分类
林业 | 6篇 |
农学 | 1篇 |
基础科学 | 2篇 |
5篇 | |
综合类 | 36篇 |
农作物 | 1篇 |
水产渔业 | 2篇 |
畜牧兽医 | 69篇 |
园艺 | 2篇 |
植物保护 | 3篇 |
出版年
2021年 | 4篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2014年 | 4篇 |
2013年 | 8篇 |
2012年 | 10篇 |
2011年 | 4篇 |
2010年 | 7篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1945年 | 1篇 |
1940年 | 1篇 |
1935年 | 1篇 |
1934年 | 1篇 |
1933年 | 1篇 |
1932年 | 1篇 |
1927年 | 1篇 |
1908年 | 1篇 |
1899年 | 1篇 |
排序方式: 共有127条查询结果,搜索用时 15 毫秒
81.
Hambler C Canney SM Coe MJ Henderson PA Illius AW 《Science (New York, N.Y.)》2007,316(5831):1564-7; author reply 1564-7
82.
Coe H 《Science (New York, N.Y.)》2011,331(6022):1273-1274
83.
84.
Coe WR 《Science (New York, N.Y.)》1940,91(2356):175-182
85.
86.
87.
88.
Ultrasonic shear wave velocities of MgSiO3 perovskite at 8 GPa and 800 K and lower mantle composition 总被引:1,自引:0,他引:1
YD Sinelnikov G Chen DR Neuville MT Vaughan RC Liebermann 《Science (New York, N.Y.)》1998,281(5377):677-679
Ultrasonic interferometric measurements of the shear elastic properties of MgSiO3 perovskite were conducted on three polycrystalline specimens at conditions up to pressures of 8 gigapascals and temperatures of 800 kelvin. The acoustic measurements produced the pressure (P) and temperature (T) derivatives of the shear modulus (G), namely ( partial differentialG/ partial differentialP)T = 1.8 +/- 0.4 and ( partial differentialG/ partial differentialT)P = -2.9 +/- 0.3 x 10(-2) gigapascals per kelvin. Combining these derivatives with the derivatives that were measured for the bulk modulus and thermal expansion of MgSiO3 perovskite provided data that suggest lower mantle compositions between pyrolite and C1 carbonaceous chondrite and a lower mantle potential temperature of 1500 +/- 200 kelvin. 相似文献
89.
Kindu Mekonnen Roland J. Buresh Richard Coe Kering Maru Kipleting 《Agroforestry Systems》1998,42(3):265-282
Measurements of root and nutrient distributions in agroforestry systems have often been obtained from unreplicated plots.
We, therefore, measured the vertical and horizontal distribution of root length and soil nitrate in replicated plots of sesbania
[Sesbania sesban (L.) Merr.] to assess plot-to-plot variation and identify appropriate sampling schemes. Sampling was on profile
walls exposed from pits at two on-farm sites (Ochinga and Muange) in Kenya. At Ochinga, soil was sampled at 27 0.15-m depth
intervals and eight 0.15-m-wide locations perpendicular to 2.25-m-wide rows of 19-month-old sesbania. At Muange, sampling
was 18 months after establishment of sesbania from seedlings with a 1 m by 1 m spacing. Soil was sampled at 17 0.15-m depth
intervals and nine 0.15-m-wide sampling locations – one exactly below the tree and four each on opposite sides of the tree.
Root length density generally decreased with distance from sesbania and with soil depth. Soil nitrate, however, followed different
trends in the four replications at Ochinga and the three replications at Muange. At Ochinga, nitrate above 2.5-m depth clearly
increased with distance from the tree in two replications but followed no distinct trend in another replication. At Muange,
nitrate above 1.2-m depth decreased with distance from the tree in one replication, increased with distance from the tree
in another replication and followed no clear trend in another replication. The suitability of various sampling schemes for
measuring root length and nitrate was accessed from percent bias between measured values at sampling locations in the scheme
and actual values for an entire transect of sampling locations. Bias associated with selection of sampling locations tended
to be higher within the 2.25-m-wide sesbania rows than the 1 m by 1 m sesbania spacing. Soil sampling in systems with rows
of young trees should be at several locations along a transect perpendicular to tree rows in order to minimize bias.
This revised version was published online in June 2006 with corrections to the Cover Date.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
90.
SM Ossedryver GI Baldwin BM Stone RA McKenzie AW van Eps S Murray MT Fletcher 《Australian veterinary journal》2013,91(4):143-149
Three ponies continuously grazed a pasture containing an estimated 24% Indigofera spicata (wet weight basis) for 4–6 weeks in April and May 2004. They developed ataxia, paresis, depression, muscle fasciculations, dysphagia, ptyalism and halitosis. Two also developed corneal opacity. One pony recovered with supportive treatment, but the other two were euthanased and necropsied. Neuropathology was not present in either case, but both livers had periacinar and periportal lymphocytic infiltrations and hydropic degeneration of mid‐zonal hepatocytes, with mild to moderate periacinar necrosis also evident in one. The I. spicata contained 2.66 mg 3‐nitropropionic acid (3‐NPA)/g dry matter and 1.5 mg indospicine/g dry matter. Indospicine, but not 3‐NPA, was detected in serum from both of the euthanased ponies and indospicine was detected in heart, liver and muscle from the one pony in which this assay was performed. The clinical syndrome closely resembled ‘Birdsville horse disease’ caused by I. linnaei and was similar to that reported in horses poisoned by the closely related species I. hendecaphylla and to 3‐NPA poisoning of other animals, including humans. 3‐NPA is thought to cause this neurological syndrome. To our knowledge, this is the first authenticated report of I. spicata poisoning in grazing animals. We also report here the first published evidence that 3‐NPA and indospicine exist in naturalised I. spicata in Australia and of the formation of indospicine residues in tissues of animals grazing paddocks infested with I. spicata. 相似文献