全文获取类型
| 收费全文 | 269篇 |
| 免费 | 25篇 |
专业分类
| 林业 | 19篇 |
| 农学 | 11篇 |
| 84篇 | |
| 综合类 | 7篇 |
| 农作物 | 23篇 |
| 水产渔业 | 29篇 |
| 畜牧兽医 | 80篇 |
| 园艺 | 9篇 |
| 植物保护 | 32篇 |
出版年
| 2022年 | 1篇 |
| 2021年 | 4篇 |
| 2020年 | 21篇 |
| 2019年 | 12篇 |
| 2018年 | 26篇 |
| 2017年 | 11篇 |
| 2016年 | 17篇 |
| 2015年 | 16篇 |
| 2014年 | 14篇 |
| 2013年 | 20篇 |
| 2012年 | 26篇 |
| 2011年 | 21篇 |
| 2010年 | 8篇 |
| 2009年 | 10篇 |
| 2008年 | 7篇 |
| 2007年 | 15篇 |
| 2006年 | 14篇 |
| 2005年 | 9篇 |
| 2004年 | 7篇 |
| 2003年 | 8篇 |
| 2002年 | 3篇 |
| 2001年 | 1篇 |
| 2000年 | 4篇 |
| 1999年 | 1篇 |
| 1998年 | 1篇 |
| 1997年 | 3篇 |
| 1996年 | 1篇 |
| 1995年 | 2篇 |
| 1994年 | 1篇 |
| 1993年 | 2篇 |
| 1992年 | 1篇 |
| 1991年 | 1篇 |
| 1989年 | 2篇 |
| 1987年 | 1篇 |
| 1985年 | 1篇 |
| 1981年 | 1篇 |
| 1979年 | 1篇 |
排序方式： 共有294条查询结果，搜索用时 171 毫秒
1.
Movements of bank voles (Clethrionomys glareolus) were studied in a farmland mosaic in Poland. Distances crossed by animals in short-time periods are significantly longer in heterogenous than in homogenous habitats. In long-time and large-spatial scales, a significant portion of the animals in a population travel among habitat elements of the mosaic, reducing the degree of isolation of patch populations and decreasing the probability of local extinction. 相似文献
2.
Birds obtained by embryo engineering are used to study embryo development and to produce transgenic birds. As this method of producing birds still generate strong emotions of the public opinion head ornaments, testes and semen characteristics of sex chimera roosters were examined to check whether they differ from chickens obtained by non‐manipulated methods. Measurements of head ornaments, testes and semen were correlated with each other. Semen quality factor (SQF) was calculated, as well as the level of fluctuating asymmetry (FA) of bilateral traits (wattles and testes). Positive correlation was found for comb width and wattle length and comb thickness and sperm concentration. Semen characteristics and FA did not exceed the level encounter in other chicken lines. Results obtained indicate that germline chimeras are similar in appearance of secondary sexual traits, and semen and testes characteristics to chickens produced in non‐manipulated way. 相似文献
3.
P. Racewicz M. Majewski Z. E. Madeja A. Łukomska M. Kubiak 《British poultry science》2020,61(2):122-131
ABSTRACT
1. The increase in microbial resistance, and in particular multiple drug resistance (MDR), is an increasing threat to public health. The uncontrolled use of antibiotics and antibacterial chemotherapeutics in the poultry industry, especially in concentrations too low to cause inhibition, and the occurrence of residues in feed and in the environment play a significant role in the development of resistance among zoonotic food-borne microorganisms.
2. Determining the presence and transmission methods of resistance in bacteria is crucial for tracking and preventing antibiotic resistance. Horizontal transfer of genetic elements responsible for drug resistance is considered to be the main mechanism for the spread of antibiotic resistance.
3. Of the many well-known genetic elements responsible for horizontal gene transfer, integrons are among the most important factors contributing to multiple drug resistance. The mechanism of bacterial drug resistance acquisition through integrons is one of the essential elements of MDR prevention in animal production.
4.
Szalińska Ewa Orlińska-Woźniak Paulina Wilk Paweł 《Journal of Soils and Sediments》2020,20(6):2641-2652
Journal of Soils and Sediments - This study analyzes the variability of sediment loads under variant climate change and land use scenarios in a Carpathian catchment with a dam reservoir. The areas... 相似文献
5.
Baranowska-Wójcik Ewa Szwajgier Dominik Winiarska-Mieczan Anna 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(1):30-32
Plant Foods for Human Nutrition - Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized, among others by abnormal levels of acetyl- and butyrylcholinesterase in... 相似文献
6.
Dorota Miliszkiewicz Piotr Wieczorek Barbara Lejczak Ewa Kowalik Pawel Kafarski 《Pest management science》1992,34(4):349-354
Phosphonic and phosphinic acid analogues of glutamic and aspartic acids were synthesized and screened for herbicidal activity on Lepidium sativum L. Depending on the chemical structure, they exhibited significant or moderate herbicidal activity against L. sativum roots (with some representatives being equipotent with phosphinothricin), while their influence on shoot growth was negligible. Cucumis sativus L. appeared to be more tolerant to these analogues. The origin of this selectivity remains to be determined. 相似文献
7.
8.
Aarestrup FM AgersŁ Y Ahrens P JŁrgensen JC Madsen M Jensen LB 《Veterinary microbiology》2000,74(4):353-364
The species distribution, susceptibility to 19 antimicrobial agents and presence of selected genes encoding resistance to macrolides, streptogramins and tetracyclines were examined among 118 staphylococcal isolates from infections of poultry in Denmark. Isolates were identified using a combination of conventional biochemical testing and 16S rDNA sequencing. The most common species were Staphylococcus aureus (83), Staphylococcus hyicus (11), Staphylococcus xylosus (9) and Staphylococcus cohnii (6). The isolates were susceptible to most antimicrobials tested. A high frequency of S. aureus (30%) was resistant to ciprofloxacin. Only six (7%) S. aureus isolates and one Staphylococcus saprophyticus were penicillin resistant. Resistance to sulphamethoxazole was observed among 16 (19%) of S. aureus isolates and two coagulase negative staphylococci (CNS). Twenty (24%) of the S. aureus isolates were resistant to erythromycin and 19 of these isolates contained the ermA gene, whereas the remaining isolate contained the ermC gene. Eleven (48%) of the novobiocin resistant CNS were resistant to erythromycin and all these isolates contained the ermA gene. Two isolates identified as S. xylosus, were found to be resistant to streptogramins and both contained the vatB- and the vgaB-genes. Thirty-nine (47%) of the S. aureus isolates, three of nine S. hyicus and eight of the 23 novobiocin resistant CNS were tetracycline resistant and all contained the tet(K) gene. A single S. aureus isolate also contained the tet(M) gene. The present study showed a frequent occurrence of resistance to fluoroquinolones, tetracycline and macrolides among staphylococci isolated from broilers in Denmark, whereas the occurrence of resistance to other antimicrobial agents remains low. Similar genes, encoding resistance to erythromycin, tetracycline and streptogramins to those previously observed, were detected. 相似文献
9.
On the basis of the fresh weight of apple fruit and its peel and the concentration of bioactive compounds, the total quantity of L-cysteine, glutathione, ascorbate, flavonols, and anthocyanins as well as phenolics was evaluated in a wide range of cultivars and two growing seasons. Apple peel as a contributor to the entire apple quantity of the examined components considerably differed in relation to the investigated compounds and was also highly cultivar dependent. A great amount of flavonols was found in apple peel (approximately 40%), followed by ascorbate (approximately 30%) and total phenolics (approximately 20%), while the lowest contribution was assessed for thiols (approximately 11% and 14% for L-cysteine and total quantity of glutathione, respectively), based on average values for both years. Seasonal variations in the quantity of antioxidants was more pronounced in apple peel, whereas the contribution of apple peel to the whole fruit was predominantly affected by the genotype. A very high positive correlation existed between apple peel and the whole fruit quantity of antioxidants. 相似文献
10.
Urszula Paslawska Agnieszka Noszczyk-Nowak Robert Paslawski Adrian Janiszewski Liliana Kiczak Dorota Zysko Jozef Nicpon Ewa A Jankowska Andrzej Szuba Piotr Ponikowski 《Acta veterinaria Scandinavica》2014,56(1)