全文获取类型
收费全文 | 229篇 |
免费 | 9篇 |
国内免费 | 4篇 |
专业分类
林业 | 25篇 |
农学 | 30篇 |
基础科学 | 2篇 |
49篇 | |
综合类 | 11篇 |
农作物 | 28篇 |
水产渔业 | 30篇 |
畜牧兽医 | 27篇 |
园艺 | 6篇 |
植物保护 | 34篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 6篇 |
2014年 | 15篇 |
2013年 | 20篇 |
2012年 | 17篇 |
2011年 | 15篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有242条查询结果,搜索用时 15 毫秒
171.
Vanilla (Vanilla planifolia) is a crop of great commercial importance as the source of natural vanillin, a major component of flavor industry. The primary gene pool of V. planifolia is narrow and is evidently threatened due to destruction of its natural habitats making the secondary gene pool important as a source of desirable traits especially for resistance to diseases. Many species of vanilla are considered rare and endangered hence an urgent need to conserve them, arises. Effective procedures for micropropagation and in vitro conservation by slow growth in selected species of vanilla, are described. Synthetic seed technology was standardized by encapsulating 3–5 mm in vitro regenerated shoot buds and protocorms in 4% sodium alginate, which could be stored up to 10 months with 80% germination in sterile water at 22 ± 2 °C. In vitro conservation technology of Vanilla was standardized and shoot cultures could be maintained for more than 1 year without subculture, on slow growth medium, i.e. Murashige and Skoog medium supplemented with 15 g l−1 each of sucrose and mannitol in sealed culture vessels at 22 ± 2 °C. These cultures were maintained in vitro for more than 7 years with yearly subculture. The conserved material could be retrieved and multiplied normally in MS medium with 1.0 mg l−1 BA and 0.5 mgl −1 IBA. The in vitro conserved plants showed good growth and developed into normal plants. This synseed and in vitro conservation system can be utilized for conservation and exchange of vanilla genetic resources. 相似文献
172.
Munday JS Thompson D Finch SC Babu JV Wilkins AL di Menna ME Miles CO 《New Zealand veterinary journal》2008,56(3):145-148
CASE HISTORY: A 1-year-old, intact male Labrador-cross dog vomited after eating walnuts that had been on the ground for 5 months. The dog then developed tremors, ataxia, increased salivation, and hyperaesthesia. CLINICAL FINDINGS: The dog had marked generalised tremors, ataxia and a temperature of 39.9 degrees C. Both pupils were of normal size and normally responsive to light. Vomiting was induced, and walnut shell was visible in the vomitus. DIAGNOSIS: Due to the sudden onset of tremors, lack of exposure to other convulsive toxins, and the evidence of ingestion of walnuts, the provisional diagnosis was tremorgenic mycotoxicosis. The dog was treated symptomatically, and made a full recovery over 18 hours. Tremorgenic mycotoxins were detected within walnuts collected from the dog's environment. CLINICAL RELEVANCE: Fungi that produce tremorgenic mycotoxins are present in New Zealand. Intoxication should be suspected in dogs that suddenly develop muscle tremors, especially if there is a history of ingestion of mouldy food 2-3 hours prior to the development of tremors. 相似文献
173.
174.
Kumar Ravishankar Kumar Rabindra Mittal Sunil Arora Meenu Babu J. Nagendra 《Journal of Soils and Sediments》2016,16(2):605-620
Journal of Soils and Sediments - Arsenic (As) contamination of groundwater has received significant attention recently in district Bathinda, due to consequent health risk in this region. Soil is... 相似文献
175.
Variation in oil content and fatty acid profile (FAP) of Calophyllum inophyllum; a potential biodiesel feedstock species were studied at different maturity stages and biodiesel quality parameters were estimated based on the FAP. A steady increase in oil content was observed with maturity. Variation in palmitic (16:0) and linoleic (18:2) acids followed exactly opposite trends where palmitic acid content has decreased and linoleic acid content has increased 77 days after anthesis. Oleic acid (18:1) content has shown a steady increase. Stearic acid (18:0) content remained steady up to 68 days after anthesis and then felt slightly in 77 days after anthesis. Linoleic and eicosanoic acids were found to exist in low concentrations demonstrated very little compositional variation with fruit maturity. Estimated biodiesel parameters of all maturity stages were found to comply with industrial standards. Even though 48 days after anthesis had the most ideal FAP for biodiesel production, ∼77 days after anthesis is preferred point to harvest due to higher oil content. 相似文献
176.
Sharanabasappa B. Yeri Kenta Shirasawa Manish K. Pandey M. V. C. Gowda Vanhi Sujay Manda Shriswathi Hajisaheb L. Nadaf Babu N. Motagi S. Lingaraju A. R. S. Bhat Rajeev K. Varshney P. U. Krishnaraj Ramesh S. Bhat 《Plant Breeding》2014,133(1):80-85
Heterogeneous inbred families segregating for rust resistance were identified from the two crosses involving susceptible (TAG 24 and TG 26) and resistant (GPBD 4) varieties of peanut. Rust‐resistant (less than score 5) and rust‐susceptible (more than score 5) plants were identified in each HIF and evaluated under rust epiphytotic conditions. The set of plants belonging to the same HIF, but differing significantly in rust resistance, not in other morphological and productivity traits, was regarded as near‐isogenic lines (NILs). Largely, rust‐resistant NILs had GPBD 4‐type allele, and susceptible NILs carried either TAG 24 or TG 26‐type allele at the three SSR loci (IPAHM103, GM1536 and GM2301) linked to a major genomic region governing rust resistance. Comparison of the remaining genomic regions between the NILs originating from each of the HIFs using transposon markers indicated a considerably high similarity of 86.4% and 83.1% in TAG 24 × GPPBD 4 and TG 26 × GPBD 4, respectively. These NILs are useful for fine mapping and expression analysis of rust resistance. 相似文献
177.
A. Anuraj V. K. Tiwari P. P. Suresh Babu G. B. Sreekanth P. Srinivas Rao 《Journal Of Applied Aquaculture》2013,25(2):150-159
We sought the source of gram-negative bacteria associated with giant freshwater prawns in a hatchery that was previously observed with severe mortality of prawn larvae during the sixth to seventh zoea stages. After thorough disinfection, the gram-negative bacterial microflora of broodstock, larvae, larval rearing tank (LRT) water, and other intake systems were examined for bacteria. Enterobacteriaceae and Vibrio were the major bacteria isolated from the larvae. The present study suggests that Enterobacteriaceae may be introduced via the broodstock and Vibrio via the LRT water. 相似文献
178.
179.
180.
Rakesh Minocha Stephanie Long Palaniswamy Thangavel Subhash C. Minocha Christopher Eagar Charles T. Driscoll 《Forest Ecology and Management》2010
Acidic deposition has caused a depletion of calcium (Ca) in the northeastern forest soils. Wollastonite (Ca silicate) was added to watershed 1 (WS1) at the Hubbard Brook Experimental Forest (HBEF) in 1999 to evaluate its effects on various functions of the HBEF ecosystem. The effects of Ca addition on foliar soluble (extractable in 5% HClO4) ions, chlorophyll, polyamines, and amino acids were studied in three hardwood species, namely sugar maple, yellow birch, and American beech. We further analyzed these effects in relation to elevation at Ca-supplemented WS1 and reference WS3 watersheds. Foliar soluble Ca increased significantly in all species at mid and high elevations at Ca-supplemented WS1. This was accompanied by increases in soluble P, chlorophyll, and two amino acids, glutamate and glycine. A decrease in known metabolic indicators of physiological stress (i.e., the amino acids, arginine and γ-aminobutyric acid (GABA), and the diamine, putrescine) was also observed. In general, these changes were species-specific and occurred in an elevation dependent manner. Despite an observed increase in Ca at high elevation for all three species, only sugar maple exhibited a decrease in foliar putrescine at this elevation indicating possible remediation from Ca deficiency. At higher elevations of the reference WS3 site, foliar concentrations of Ca and Mg, as well as Ca:Mn ratios were lower, whereas Al, putrescine, spermidine, and GABA were generally higher. Comparison of metabolic data from these three species reinforces the earlier findings that sugar maple is the most sensitive and American beech the least sensitive species to soil Ca limitation. Furthermore, there was an increase in sensitivity with an increase in elevation. 相似文献