全文获取类型
收费全文 | 251篇 |
免费 | 30篇 |
专业分类
林业 | 4篇 |
农学 | 3篇 |
35篇 | |
综合类 | 22篇 |
农作物 | 16篇 |
水产渔业 | 37篇 |
畜牧兽医 | 154篇 |
园艺 | 2篇 |
植物保护 | 8篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 14篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 8篇 |
2015年 | 16篇 |
2014年 | 7篇 |
2013年 | 30篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 12篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 18篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1952年 | 1篇 |
1947年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有281条查询结果,搜索用时 31 毫秒
21.
Francesco Frati Ilaria Negri Pietro P. Fanciulli Marco Pellecchia Vincenzo De Paola Valerio Scali Romano Dallai 《Pedobiologia》2004,48(5-6):461-468
The Gram-negative -Proteobacterium Wolbachia pipientis has been described as an obligate endosymbiont in many arthropod species, where it induces a variety of reproductive alterations, including parthenogenesis. Recently, this microorganism has also been detected in the parthenogenetic collembolan Folsomia candida. Here, we confirm the occurrence of the endosymbiont also in two Italian parthenogenetic populations of F. candida using ultrastructural (electron microscopy) and molecular (PCR screening on two bacterial genes) evidence. The strain isolated in the Italian populations has almost-identical gene sequences compared to that previously isolated in other populations of F. candida. In addition, we discovered a population of Folsomia cf. candida, which showed the presence of both males and females. This population is not infected by Wolbachia. A screening of two mitochondrial genes (COI and COII) showed that the bisexual population has high levels of genetic divergence in comparison with the parthenogenetic ones, even suggesting the possibility that it belongs to a different species. Furthermore, the remarkably high levels of genetic divergence between the two parthenogenetic populations suggests a possible influence of Wolbachia on inducing such differentiation, and, in the long term, speciation. 相似文献
22.
Advanced reproductive techniques in goats. 总被引:2,自引:0,他引:2
K N Bretzlaff J E Romano 《Veterinary Clinics of North America: Food Animal Practice》2001,17(2):421-34, viii
The use of ultrasonography for pregnancy diagnosis and reproductive tract evaluation in the goat has become more common in the past decade. Pregnancy-specific hormone assays are commercially available for pregnancy determination in goats. Hormonal methods of synchronization of estrus for artificial insemination have been refined, but a number of factors still make pregnancy results variable. Caprine embryo transfer is widely used commercially. More advanced reproductive techniques such as in-vitro production of embryos and cloning have been accomplished in goats; success rates with these techniques will likely rapidly improve. 相似文献
23.
24.
25.
Roupie V Viart S Leroy B Romano M Trinchero N Govaerts M Letesson JJ Wattiez R Huygen K 《Veterinary immunology and immunopathology》2012,145(1-2):74-85
Mycobacterium avium subsp. paratuberculosis (Map), the etiological agent of chronic enteritis of the small intestine in domestic and wild ruminants, causes substantial losses to livestock industry. Control of this disease is seriously hampered by the lack of adequate diagnostic tools and vaccines. Here we report on the immunogenicity of eight Map specific antigens, i.e. MAP1693c, Ag3, MAP2677c (identified by post-genomic and immunoproteomic analysis of Map secretome) and Ag5, Ag6, MAP1637c, MAP0388 and MAP3743 (identified by bioinformatic in silico screening of the Map genome). Strong, antigen-specific IFN-γ responses were induced in mice vaccinated with plasmid DNA encoding MAP1693c, MAP1637c, MAP0388 and MAP3743. In contrast, T cell responses in Map infected mice were directed preferentially against Ag5 and to a lesser extent against MAP3743. None of the tested DNA vaccines conferred protection against subsequent challenge with Map. 相似文献
26.
27.
Giovanna Romano Emiliano Manzo Gian Luigi Russo Giuliana d’Ippolito Adele Cutignano Maria Russo Angelo Fontana 《Marine drugs》2013,11(11):4527-4543
Oxylipins are a large and diverse family of fatty acid derivatives exhibiting different levels of oxidation of the carbon chain. They are involved in many biological functions in mammals, plants and diatoms. In this last group of organisms, they are suggested to play a role in the reproductive failure of copepod predators, showing clear pro-apoptotic effects on newborn nauplii. In this work, these compounds were tested for the ability to induce mitotic arrest in sea urchin embryos. We show for the first time that oxylipins have an increased efficacy in their corresponding methylated form. Natural oxylipins were also used as an inspiration for the rational design and synthesis of stable chemical analogs with apoptotic activity against tumor cell lines. This approach led to the synthesis of the linear C15-ketol (22) that was shown to induce apoptosis in human leukemia U-937 cells. These results are proof of the concept of the use of eco-physiological considerations as a platform to guide the search for novel drug candidates. 相似文献
28.
29.
RM Jerram CG Warman ESS Davies MC Robson AM Walker 《New Zealand veterinary journal》2013,61(4):197-201
CASE HISTORY A 3-year-old male Labrador retriever was presented with a history of dietary indiscretion followed by vomiting and abdominal pain. CLINICAL FINDINGS AND TREATMENT: Abdominal ultrasonography revealed the presence of a fluid-filled cystic structure in the region of the pancreas. Flocculent, dark fluid was drained from the cystic structure during exploratory celiotomy prior to resection of the lateral cystic wall. Omentum was sutured into the cystic cavity to provide drainage and enhance immune response. A jejunostomy feeding tube was placed. Post-surgical care consisted of antibiotic therapy. The dog was clinically normal at 1 and 7 months post-operatively and the pancreas appeared normal on final ultrasonographic examination. CLINICAL RELEVANCE: This case describes the use of omentum to provide physiological drainage of a pancreatic pseudocyst. This surgical technique may help clinicians manage patients with this condition in the future. 相似文献
30.
CASE HISTORY: An 8-month-old Labrador Retriever was referred with a history of ambiguous external genitalia. CLINICAL FINDINGS AND TREATMENT: Clitoromegaly within apparent vulval folds, and an adjacent subcutaneous mass were noticed on external examination. An intra-abdominal testicle, with epididymis and suspected vas deferens ducts, was found during exploratory celiotomy. Incision over the subcutaneous mass revealed the accompanying testicle. Clitoridectomy was performed and an os clitoris removed. Normal juvenile testes were diagnosed on histology of the gonads. Chromosomal studies revealed a normal 78, XY male chromosomal constitution. Due to the combination of a male karyotype (78, XY), the presence of testicular tissue in the gonads, and the appearance of the external genitalia, a diagnosis of male pseudohermaphroditism (MPH) was made. CLINICAL RELEVANCE: This case presents the first report of MPH in a Labrador Retriever, and highlights the diagnostic steps recommended when confronted with a dog with ambiguous external genitalia. 相似文献