全文获取类型
收费全文 | 324篇 |
免费 | 5篇 |
专业分类
林业 | 14篇 |
农学 | 11篇 |
基础科学 | 5篇 |
36篇 | |
综合类 | 90篇 |
农作物 | 16篇 |
水产渔业 | 6篇 |
畜牧兽医 | 130篇 |
园艺 | 2篇 |
植物保护 | 19篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 7篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 7篇 |
2011年 | 22篇 |
2010年 | 18篇 |
2009年 | 11篇 |
2008年 | 25篇 |
2007年 | 5篇 |
2006年 | 8篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 9篇 |
2001年 | 4篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1981年 | 2篇 |
1979年 | 5篇 |
1977年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1966年 | 2篇 |
1965年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有329条查询结果,搜索用时 187 毫秒
101.
Lipid composition of muscle and adipose tissue from crossbred ram, wether and cryptorchid lambs 总被引:3,自引:0,他引:3
Lambs from rams (R), cryptorchids (C) and wethers (W) were examined to compare with the dietary guidelines for humans on fat and cholesterol intake. Twenty-four lambs were assigned to treatments as R, C or W at weaning (60 d). Each lamb had ad libitum access to a 77:23% forage:concentrate diet containing 11.7% crude protein and 1.84 Mcal ME/kg. The experiment was terminated when the lambs reached 50 kg body weight. Lipid composition of the longissimus muscle (LM) and s.c. adipose tissue was determined by gas-liquid chromatography. Rams has less (P less than .01) s.c. fat (cm) and i.m. lipid (%) (.26 cm; 3.*%) than W (.56 cm; 4.9%). Total polyunsaturated fatty acids were greater (P less than .01) in the LM of R (7.06%) than in LM of W (5.21%). Rams had higher percentages of C18:2, C18:3, C20:4 and C18:1 in their LM than W did. On the basis of a 100-g serving of LM, R had 1.73, C had 2.15 and W had 2.21 g saturated fatty acids. There were no (P less than .01) differences among sex types for cholesterol content of LM, which averaged 66.6 mg/100 g wet tissue. The only major difference of the s.c. fat lipid composition was in saturated fatty acids. Wethers had higher (P less than .01) saturated fatty acids (51.4%) than C 46.8%) and R (43.3%). Based on the lipid composition of these three types of lambs, the LM muscle from young R lambs approached dietary fat guidelines for humans more closely than did that from castrates. 相似文献
102.
103.
Jonathan L. Whitworth Richard G. Novy Jeffrey C. Stark Stephen L. Love Michael K. Thornton Brian A. Charlton Solomon Yilma N. Richard Knowles Mark J. Pavek Xiaohong Wang Joseph J. Pavek 《American Journal of Potato Research》2014,91(5):447-458
Huckleberry Gold is a purple-skin, yellow-flesh fresh market cultivar with similar culinary qualities to the market standard Yukon Gold. It has lower specific gravity, sucrose and vitamin C content, but a significantly higher level of tuber antioxidants than Yukon Gold. Notable disease resistant characteristics are Potato virus X resistance based on the presence of molecular markers for the PVX resistance genes, Nb and Rx1. In addition it also has the H1 gene present which confers resistance to the potato cyst nematode, Globodera rostochiensis, which has been confirmed by bioassay to pathotype Ro1. The size profile of Huckleberry Gold is smaller than Yukon Gold, allowing a better fit into specialty markets that are geared to smaller size for fresh use. Huckleberry Gold represents the first purple-skin, yellow-flesh cultivar to come from the Northwest (Tri-State) Potato Variety Development program. 相似文献
104.
Cecilia M. Onyango Jeremy Harbinson Jasper K. Imungi Solomon S. Shibairo Olaf van Kooten 《Journal of plant nutrition》2013,36(3):342-365
The influence of manure and diammonium phosphate (DAP) mineral fertilizer on germination, leaf nitrogen content, nitrate accumulation and yield of vegetable amaranth (Amaranthus hypochondriacus) was investigated. Field trials were set up at the University of Nairobi Field Station at the Upper Kabete Campus during the long rains of March–May in 2007 and 2008. Trials were laid out as complete randomized block design with four fertilization treatments: 20, 40, and 60 kg nitrogen (N) ha?1 supplied by DAP (18:46:0), 40 kg N ha?1 supplied by cattle manure and an unfertilized control variant. The vegetables were harvested at three maturity stages at 6, 7, and 8 weeks after planting. Results indicated that there were significant differences between treatments in germination percentage, leaf nitrogen content, nitrate accumulation and vegetable yield. Plants that received manure had a higher germination percentage than those that received the same amount of N supplied by the chemical fertilizer DAP. The yields generally increased from week 6 to week 8. The highest yield was recorded in plots receiving 40 kg N ha?1 from DAP at eight weeks after planting. Plots that were supplied with manure recorded the lowest yield when compared to the fertilizer treated plots at all rates. Leaf nitrogen content increased with increasing rate of N but only when N was supplied by DAP fertilizer. The leaf nitrogen content decreased with increasing age of the plants. The leaf nitrate content increased with increase in DAP application rate. Results indicate that manure application produced quality vegetables in terms of low nitrate levels, but leaf nitrogen and vegetable yields were low. DAP application effected higher yields, but the vegetables had high though acceptable nitrate levels. 相似文献
105.
Tezira A. Lore Jasper K. Imungi Kamau Mubuu 《Journal Of Agricultural & Food Information》2013,14(2):132-150
There was much public debate in Kenya about genetically modified (GM) crops when the national Biosafety Bill went through the parliamentary process toward enactment into law. This study analyzed how GM crops were framed in three mainstream Kenyan newspapers—the Daily Nation, The Standard, and Taifa Leo—during the period. The agriculture frame was predominant in the Daily Nation and The Standard, while the safety and regulation frames dominated coverage in Taifa Leo. Only 34.7% of articles were neutral in tone. Scientists and government officials, who generally spoke in favor of GM crops, were the most frequently quoted sources. Recommendations to improve the quality of coverage include training of journalists to ensure objective and balanced reporting. 相似文献
106.
Aishatu Abubakar Lushaikyaa Allam Solomon O. Okaiyeto Ayuba Caleb Kudi Shehu U. Abdullahi Peter H. Brooks Madhu Goyal 《Tropical animal health and production》2013,45(7):1505-1508
The prevalence of mycobacterial infection among lactating Fulani cows was investigated in the Federal Capital Territory, Abuja and Kaduna State of Nigeria. Tuberculin testing using single comparative intradermal tuberculin test showed a 14.6 % positive, 4 % doubtful, and 81.4 % negative reactors. Mycobacterial infection was found to be present in the nomadic (constantly moving) and seminomadic (limited movement) management systems studied but management showed no significant effect on the prevalence of the disease. However, the prevalence was significantly higher in older age groups than the younger ones (P?<?0.05). 相似文献
107.
Solomon Benor Sebsebe Demissew Karl Hammer Frank R. Blattner 《Genetic Resources and Crop Evolution》2012,59(6):1125-1146
In this study, we investigated the genetic diversity and relationships in C. olitorius by analysing populations representing different distribution areas, and developed a hypothesis on the origin and spread of the species in the pantropics. We employed amplified fragment lengths polymorphism (AFLP) and morphometric analyses in a total of 101 C. olitorius accessions. Results of both data sets are mostly congruent. The molecular analysis indicated generally low genetic diversity within populations and the Nei’s gene diversity (He) ranged from 0.0457 to 0.0955 with a mean of 0.0763. Qualitative traits, especially related to leaf morphology, branching habit and stipule color were the taxonomically most informative characters. The highest morphological variability occurred within African accessions, indicating that this species originally evolved in Africa. In both analyses, the Asian materials were nested within African populations, especially with those from North and East Africa. This indicates an African origin of the species and we hypothesise that dispersal occurred via the Mediterranean–Indian trade routes instead of natural migration along the coasts from western Africa to the Indian subcontinent. Both analyses revealed materials from Ethiopia to be quite distinct. The highest number of private bands (N?=?35), percent polymorphism (29.29%), and gene diversity (0.0955) were also detected in wild accessions collected from Ethiopia, suggesting a long-term spatial isolation of C. olitorius populations in the country. Germplasm samples from this region could therefore be a useful source of genetic variation in jute breeding programs. 相似文献
108.
109.
110.
Weisse C Berent A Todd K Clifford C Solomon J 《Journal of the American Veterinary Medical Association》2006,229(2):226-234
OBJECTIVE: To evaluate use of balloon-expandable and self-expanding metallic stents in management of malignant urethral obstructions in dogs. DESIGN: Original study. ANIMALS: 12 dogs with malignant urethral obstructions. PROCEDURES: The extent and location of urethral obstructions and the diameter of adjacent unaffected luminal segments were determined by use of fluoroscopically guided wires and measuring catheters. Stents were chosen to extend approximately 1 cm proximal and distal to the obstruction. Stent diameters were chosen to be approximately 10% greater than the diameter of healthy portions of the urethra to prevent displacement. Stents were placed in the urethra under fluoroscopic guidance to restore luminal patency. RESULTS: 3 dogs received balloon-expandable metallic stents, and 9 dogs received self-expanding metallic stents. The placement procedures were rapid, safe, and effective at restoring luminal patency and were not associated with major complications. Complications included recurrent urethral obstruction secondary to blood clot formation and urethral edema in 1 dog and stent dislodgement into the urinary bladder in 1 dog. All dogs were able to urinate immediately after the procedure. Nine dogs (3/4 females and 6/8 males) were continent or mildly incontinent after stent placement. Of the remaining 3 dogs, 2 developed severe incontinence and 1 had an atonic bladder. Seven dogs were considered to have good to excellent outcome, 3 had fair outcome, and 2 had poor outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Transurethral placement of metallic stents was a safe and effective palliative treatment option for dogs with malignant urethral obstructions. 相似文献