全文获取类型
收费全文 | 1378篇 |
免费 | 6篇 |
国内免费 | 28篇 |
专业分类
林业 | 37篇 |
农学 | 28篇 |
129篇 | |
综合类 | 664篇 |
农作物 | 71篇 |
水产渔业 | 4篇 |
畜牧兽医 | 457篇 |
园艺 | 1篇 |
植物保护 | 21篇 |
出版年
2013年 | 8篇 |
2012年 | 66篇 |
2011年 | 76篇 |
2010年 | 21篇 |
2009年 | 20篇 |
2008年 | 77篇 |
2007年 | 85篇 |
2006年 | 76篇 |
2005年 | 75篇 |
2004年 | 64篇 |
2003年 | 52篇 |
2002年 | 57篇 |
2001年 | 64篇 |
2000年 | 65篇 |
1999年 | 25篇 |
1998年 | 7篇 |
1997年 | 12篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 15篇 |
1992年 | 14篇 |
1991年 | 16篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1984年 | 6篇 |
1982年 | 9篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1976年 | 5篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1970年 | 22篇 |
1969年 | 31篇 |
1968年 | 29篇 |
1967年 | 34篇 |
1966年 | 34篇 |
1963年 | 76篇 |
1958年 | 6篇 |
1957年 | 7篇 |
1925年 | 5篇 |
1906年 | 7篇 |
1905年 | 4篇 |
1902年 | 4篇 |
1901年 | 4篇 |
1892年 | 5篇 |
排序方式: 共有1412条查询结果,搜索用时 15 毫秒
1.
2.
Fenimore RL Adams DS Puls R 《The Canadian veterinary journal. La revue veterinaire canadienne》1983,24(2):41-45
Moderate to extremely low levels of selenium in hay were related to marginally deficient levels of selenium in sera from cattle in the Windermere Valley of southeastern British Columbia. Deficiency was most pronounced in cattle fed local hay during the winter or grazed on fertilized/irrigated pastures. Cattle on range had adequate levels of serum selenium. When sodium selenite was fed at 1.0 and 3.5 mg per head per day, serum selenium levels increased commensurate with the dose. Clinical observations indicated that a variety of clinical problems disappeared after injection or supplementation with selenium/vitamin E. 相似文献
3.
Phycomyces sporangiophores showl a growth response to a light stimus and an avoidance bending response to a physical barrier. A bluie-light stimnlluts Imninisteredl in conjunction with a barrier interferes with the avoidance bending sponse. This interference begins ifter a latency of abotit 3 minultes atndt continues a period of 4 to 5 minutes. 相似文献
4.
5.
6.
Dimski DS Brooks CL Johnson SE 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1990,19(2):40-44
Type III procollagen peptide (P-3-P) is a serum marker for hepatic fibrosis in humans. The utility of a commercially available radioimmunoassay for P-3-P was evaluated in the dog. The specificity of the assay was assessed by polyacrylamide gel electrophoresis (PAGE) of canine serum and purified bovine P-3-P, followed by Western immunoblotting with rabbit aniti-P-3-P serum. The sensitivity was assessed by performing the radioimmunoassay on dilutions of sera from 22 dogs. Polyacrylamide gel electrophoresis of purified bovine P-3-P and sera from two dogs suspected of having elevated P-3-P concentrations revealed no homologous bands of staining. Western immunoblotting showed marked cross-reactivity of the high antisera concentrations with several components of the serum proteins, but none corresponding to the purified P-3-P. All tested sera from dogs had minimal competitive binding with radiolabeled P-3-P in the radioimmunoassay. Dilution curves of dog sera did not parallel either the standard curve or the dilution curve of a known test human serum. There were no statistically different P-3-P concentrations in any of the groups of dogs studied. It was concluded that currently available radioimmunoassay kits for the measurement of P-3-P in the human are not applicable in the dog. Seemingly, the structure or metabolism of canine P-3-P may vary significantly from that of the bovine or human, limiting the sensitivity and specificity of this assay in the dog. 相似文献
7.
8.
不同播期对高梁子粒淀粉含量的影响 总被引:1,自引:0,他引:1
以铁杂17号高粱为试验材料,研究了不同播期对高粱子粒淀粉含量的影响.结果表明:高粱子粒总淀粉、支链淀粉、直链淀粉含量和支链/直链淀粉比值随子粒灌浆过程推进均呈不断上升趋势,至成熟期达到最大值.其中,Ⅳ播期总淀粉、支链淀粉含量和支链/直链淀粉比值最高,为76.9%,69.1%和8.77;Ⅲ播期直链淀粉含量最高,为8.49%.适时晚播(沈阳地区在5月10~20日)可提高高粱子粒总淀粉、支链淀粉含量和支链/直链淀粉比值.改善占占质.高粱灌浆期气候因子的温度指标对淀粉积累具有重要影响,灌浆期间适宜淀粉积累的日平均温度为19.5~20.5℃. 相似文献
9.
An outbreak of goose parvovirus (GPV) infection on a Swedish goose farm in the spring of 2004 increased the mortality rates from 2% in the early unaffected hatches to 90% and 99% respectively in the two hatches following virus introduction and 40% in goslings hatched later in the same breeding season. In this paper we describe the clinical observations, diagnostic procedures, and epidemiologic investigation carried out to elucidate the source of the infection. The diagnosis was confirmed by serology, virus isolation, and sequence analysis of a 493-bp-long fragment of the VP1 gene. Phylogenetically the causative virus was closely related to pathogenic GPV strains isolated in 2003 and 2004 from Poland and the United Kingdom, respectively. The Swedish isolate exhibited less homology with pathogenic strains from Hungary and Asia and with attenuated vaccine strains. The epidemiologic investigation showed that the virus was first introduced to a contract farm (farm A) and then was transferred with newly hatched goslings to the farm that had submitted the birds for necropsy (index farm). The exact time and source of the virus introduction to farm A could not be determined with absolute certainty. Possible sources of the infection included backyard goose eggs that had been delivered to farm A for subcontract incubation and hatching, wild geese that frequented the flock of breeding geese on pasture on farm A, and a clutch of Canada goose eggs (Branta canadensis) that had been produced by wild geese and was hatched in the same machine as the eggs produced by farm A. 相似文献
10.
Brinkman EL Biller DS Armbrust LJ O'Brien RT 《Journal of the American Animal Hospital Association》2007,43(4):179-186
When performing abdominal ultrasonography in dogs, the right aspect of the liver, porta hepatis, right kidney, right adrenal gland, pancreas, and duodenum are often not fully visible from a ventral, or subcostal, approach. The right lateral intercostal plane is an alternative approach that allows evaluation of these structures. This report provides multiple case examples that demonstrate the sonographic anatomy via the right intercostal approach. Other cases are included to demonstrate indications for this approach. Animals in which the right intercostal approach may prove most useful include large- and giant-breed dogs; deep-chested dogs; dogs with gas distention of the stomach, duodenum, and colon; dogs with microhepatia; and those with abdominal effusion and pain. 相似文献