全文获取类型
收费全文 | 971篇 |
免费 | 90篇 |
专业分类
林业 | 62篇 |
农学 | 21篇 |
基础科学 | 11篇 |
146篇 | |
综合类 | 127篇 |
农作物 | 37篇 |
水产渔业 | 66篇 |
畜牧兽医 | 471篇 |
园艺 | 35篇 |
植物保护 | 85篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 20篇 |
2020年 | 28篇 |
2019年 | 24篇 |
2018年 | 38篇 |
2017年 | 39篇 |
2016年 | 49篇 |
2015年 | 24篇 |
2014年 | 30篇 |
2013年 | 49篇 |
2012年 | 53篇 |
2011年 | 64篇 |
2010年 | 24篇 |
2009年 | 30篇 |
2008年 | 58篇 |
2007年 | 36篇 |
2006年 | 27篇 |
2005年 | 26篇 |
2004年 | 25篇 |
2003年 | 36篇 |
2002年 | 44篇 |
2001年 | 22篇 |
2000年 | 25篇 |
1999年 | 18篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1983年 | 14篇 |
1978年 | 5篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 10篇 |
1971年 | 9篇 |
1969年 | 8篇 |
1968年 | 5篇 |
1967年 | 7篇 |
1963年 | 5篇 |
1952年 | 4篇 |
排序方式: 共有1061条查询结果,搜索用时 9 毫秒
1.
2.
R. J. Dixon W. J. Hartley D. R. Hutchins E. E. Lepherd Caroline Feilen † R. F. Jones † Daria N. Love † Margaret Sabine † Anne L. Wells † 《Australian veterinary journal》1978,54(3):103-105
An outbreak of perinatal foal mortality associated with a herpesvirus is described. Twenty two foals either were still-born, or died soon after birth, or were weak and soon developed severe respiratory signs, or were normal at birth and developed respiratory symptoms 18 to 24 hours later. Elevated temperatures, heart and respiratory rates were constant features. The animals were severely leucopaenic, and showed an absolute neutropaenia. At autopsy the lungs were enlarged, and showed varying degrees of aeration and moderate to severe oedema and congestion. Histopathology showed an acute focal necrotising bronchiolitis with the presence of intranuclear eosinophilic inclusion bodies. Herpesvirus was recovered from 9 foals in cell culture and identified by electron microscopy. 相似文献
3.
4.
5.
6.
Sherry Rachel Jacob MB Arunkumar Madhuban Gopal Chitra Srivastava SN Sinha 《Pest management science》2009,65(7):817-822
BACKGROUND: An efficient delivery system for seed‐protectant chemicals is needed in light of several disadvantages of conventional seed treatment methods. This study evaluates the efficacy of film‐coat application in maintaining the persistence and potency of imidacloprid on Lycopersicon esculentum (L.) Mill. seeds after simultaneous storage under ambient and regulated environment in paper and aluminium packages. RESULTS: High‐performance liquid chromatography (HPLC) revealed 0.135 mg kg?1 of herbage material to be the threshold value beyond which absolute control was obtained, and with film coating the latter was achieved even with half‐dosage seed treatment, irrespective of the storage condition. The technique provided early protection to the crop and also nullified the deleterious effects of ambient storage on the persistence and potency of the pesticide. CONCLUSION: Film coating enabled superior pesticide dosage as well as higher biological efficacy to be achieved. Hence, in addition to being an ecofriendly alternative, the technique would be a more economically viable option for storage of treated seeds. Copyright © 2009 Society of Chemical Industry 相似文献
7.
不同非洲猪瘟病毒株j5R基因及其编码蛋白的比较 总被引:5,自引:0,他引:5
根据非洲猪瘟病毒MalawiLIL20/1株j5R阅读框C端抗原决定簇序列制备的合成肽能被不同毒株感染康复猪的免疫血清识别。多聚酶链反应研究表明,9个不同毒株的j5R基因长度略有差异;蛋白转印杂交试验证明,这种基因长度的差异导致相应蛋白多肽的长度多样性。这些结果进一步证明,长度多样性是非洲猪瘟病毒基因及其编码蛋白较为普遍的特点。 相似文献
8.
Pheromones are communication chemicals and regulatory signals used by animals and represent unique tools for organisms to mediate behaviors and make “decisions” to maximize their fitness. Phenotypic plasticity refers to the innate capacity of a species to tolerate a greater breadth of environmental conditions across which it adapts to improve its survival, reproduction, and fitness. The pinewood nematode, Bursaphelenchus xylophilus, an invasive nematode species, was accidentally introduced from North America into Japan, China, and Europe; however, few studies have investigated its pheromones and phenotypic plasticity as a natural model. Here, we demonstrated a novel phenomenon, in which nematodes under the condition of pheromone presence triggered increased reproduction in invasive strains (JP1, JP2, CN1, CN2, EU1, and EU2), while it simultaneously decreased reproduction in native strains (US1 and US2). The bidirectional effect on fecundity, mediated by presence/absence of pheromones, is henceforth termed pheromone-regulative reproductive plasticity (PRRP). We further found that synthetic ascaroside asc-C5 (ascr#9), the major pheromone component, plays a leading role in PRRP and identified 2 candidate receptor genes, Bxydaf-38 and Bxysrd-10, involved in perceiving asc-C5. These results suggest that plasticity of reproductive responses to pheromones in pinewood nematode may increase its fitness in novel environments following introduction. This opens up a new perspective for invasion biology and presents a novel strategy of invasion, suggesting that pheromones, in addition to their traditional roles in chemical signaling, can influence the reproductive phenotype among native and invasive isolates. In addition, this novel mechanism could broadly explain, through comparative studies of native and invasive populations of animals, a potential underlying factor behind of the success of other biological invasions. 相似文献
9.
Christopher J. Dixon 《Veterinary ophthalmology》2016,19(1):68-72
Achromatopsia was identified in three Labrador Retriever littermates. The dogs demonstrated day blindness, negotiating obstacles under low‐light conditions, but apparently blind when outdoors. One of the dogs presented with immature bilateral diffuse posterior cortical cataracts and clinical signs of day blindness became apparent following cataract extraction surgery. Electroretinography demonstrated an absence of a cone photoreceptor response to a bright stimulus and a flicker response of 30 Hz in all three dogs. No fundic lesions have been apparent ophthalmoscopically in any of the dogs as the initial presentation of each case. No abnormalities were detected with DNA screening for known mutations of the CNGB3 gene in any of the dogs. 相似文献
10.