全文获取类型
| 收费全文 | 13898篇 |
| 免费 | 142篇 |
| 国内免费 | 86篇 |
专业分类
| 林业 | 844篇 |
| 农学 | 141篇 |
| 基础科学 | 45篇 |
| 2111篇 | |
| 综合类 | 3083篇 |
| 农作物 | 425篇 |
| 水产渔业 | 121篇 |
| 畜牧兽医 | 6837篇 |
| 园艺 | 92篇 |
| 植物保护 | 427篇 |
出版年
| 2016年 | 20篇 |
| 2015年 | 28篇 |
| 2014年 | 55篇 |
| 2013年 | 45篇 |
| 2012年 | 1094篇 |
| 2011年 | 1229篇 |
| 2010年 | 256篇 |
| 2009年 | 162篇 |
| 2008年 | 1078篇 |
| 2007年 | 1141篇 |
| 2006年 | 1081篇 |
| 2005年 | 1099篇 |
| 2004年 | 995篇 |
| 2003年 | 925篇 |
| 2002年 | 839篇 |
| 2001年 | 570篇 |
| 2000年 | 782篇 |
| 1999年 | 294篇 |
| 1998年 | 67篇 |
| 1997年 | 62篇 |
| 1996年 | 69篇 |
| 1995年 | 65篇 |
| 1994年 | 114篇 |
| 1993年 | 120篇 |
| 1992年 | 149篇 |
| 1991年 | 112篇 |
| 1990年 | 145篇 |
| 1989年 | 107篇 |
| 1988年 | 111篇 |
| 1987年 | 91篇 |
| 1986年 | 74篇 |
| 1985年 | 96篇 |
| 1984年 | 94篇 |
| 1983年 | 77篇 |
| 1982年 | 77篇 |
| 1981年 | 56篇 |
| 1980年 | 60篇 |
| 1979年 | 32篇 |
| 1978年 | 27篇 |
| 1977年 | 21篇 |
| 1976年 | 22篇 |
| 1974年 | 25篇 |
| 1969年 | 18篇 |
| 1966年 | 25篇 |
| 1963年 | 31篇 |
| 1959年 | 20篇 |
| 1957年 | 18篇 |
| 1956年 | 22篇 |
| 1955年 | 18篇 |
| 1954年 | 17篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
31.
32.
Fifty different mineral samples were tested as potential heterogeneous or epitaxial nucleants for four commonly crystallized proteins. It was found, by conventional protein crystallization techniques, that for each protein there was a set of mineral substrates that promoted nucleation of crystals at lower critical levels of supersaturation than required for spontaneous growth. Numerous examples, involving all four proteins, were observed of modification of crystal habit and, in some cases, unit cell properties promoted by the presence of the mineral nucleants. In at least one case, the growth of lysozyme on the mineral apophyllite, it was shown by lattice analysis and x-ray diffraction that the nucleation and growth of the protein crystal on the mineral was likely to involve a direct lattice match. 相似文献
33.
34.
35.
36.
Evaluation of a Killed Vaccine Against Porcine Pleuropneumonia Due to Haemophilus pleuropneumoniae 总被引：20，自引：2，他引：18
Higgins R Larivière S Mittal KR Martineau GP Rousseau P Cameron J 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(2):86-89
A bacterin containing serotypes 1 and 5 of Haemophilus pleuropneumoniae was developed for the prevention and the control of porcine pleuropneumonia. It was injected intramuscularly into three groups of ten piglets, the first group with one dose, the second one with two doses and the third one with three doses at two-week intervals. Another group of ten piglets did not receive the vaccine. All the piglets were then challenged by an aerosol of mixed suspensions of H. pleuropneumoniae serotypes 1 and 5. Two and three injections of vaccine completely prevented mortality, whereas half of the control piglets and of those receiving only one dose of vaccine died. All surviving piglets, both control and vaccinated, had severe signs of respiratory disease for at least 36 hours after exposure to challenge. Moreover, vaccination did not induce the production of antibodies at high titers. Local reactions were not noted after vaccination and at postmortem; ten weeks after the challenge, there were no signs of abscess formation or induration. 相似文献
37.
The temporary dentitions of 18 to 39-week-old lambs with a very light or a very heavy parasite burden are compared. The heavily parasitised lambs developed longer temporary incisors which tended to protrude further forward in relation to the upper dental pad. They showed absolute hypocalcaemia and hypoalbuminaemia and relative hypophosphataemia and hypoproteinaemia and in the alveolar bone of the mandible there was a reduction in ash and matrix densities and matrix mineralisation. The incisor protrusion and lengthening may have been a consequence of the loss of supporting bone, but inappetance was likely to have been a factor contributing to the lengthening. 相似文献
38.
Transitional Cell Carcinoma of the Urinary Bladder in a Beluga Whale (Delphinapterus leucas) 总被引：1，自引：0，他引：1 
下载免费PDF全文
下载免费PDF全文 Martineau D Lagacé A Massé R Morin M Béland P 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(10):297-302
A transitional cell carcinoma of the urinary bladder was found in a beluga whale stranded in the St. Lawrence middle estuary. Various organs of this animal were submitted to high resolution gas chromatography coupled with mass spectrometry analysis. High frequency of urinary bladder cancer in the human population of the same area and the presence of carcinogenic compounds in the marine environment of this animal are discussed.
Concurrent isolation of Edwardsiella tarda from various organs of this whale is also reported.
相似文献39.
40.