全文获取类型
收费全文 | 5795篇 |
免费 | 528篇 |
专业分类
林业 | 80篇 |
农学 | 37篇 |
基础科学 | 6篇 |
226篇 | |
综合类 | 43篇 |
农作物 | 50篇 |
水产渔业 | 79篇 |
畜牧兽医 | 5672篇 |
园艺 | 20篇 |
植物保护 | 110篇 |
出版年
2024年 | 6篇 |
2023年 | 97篇 |
2022年 | 17篇 |
2021年 | 36篇 |
2020年 | 198篇 |
2019年 | 36篇 |
2018年 | 165篇 |
2017年 | 166篇 |
2016年 | 121篇 |
2015年 | 175篇 |
2014年 | 258篇 |
2013年 | 289篇 |
2012年 | 240篇 |
2011年 | 271篇 |
2010年 | 197篇 |
2009年 | 272篇 |
2008年 | 206篇 |
2007年 | 130篇 |
2006年 | 124篇 |
2005年 | 120篇 |
2004年 | 187篇 |
2003年 | 179篇 |
2002年 | 193篇 |
2001年 | 169篇 |
2000年 | 123篇 |
1999年 | 125篇 |
1998年 | 172篇 |
1997年 | 184篇 |
1996年 | 160篇 |
1995年 | 160篇 |
1994年 | 140篇 |
1993年 | 150篇 |
1992年 | 175篇 |
1991年 | 148篇 |
1990年 | 186篇 |
1989年 | 132篇 |
1988年 | 114篇 |
1987年 | 146篇 |
1986年 | 54篇 |
1985年 | 80篇 |
1984年 | 83篇 |
1983年 | 79篇 |
1982年 | 36篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1977年 | 3篇 |
1972年 | 1篇 |
1966年 | 1篇 |
1962年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有6323条查询结果,搜索用时 31 毫秒
131.
132.
Alberto J. P. Nunes Hassan Sabry‐Neto Severino Oliveira‐Neto Lena Burri 《Journal of the World Aquaculture Society》2019,50(6):1048-1063
This study compared the feed preference and growth response of Litopenaeus vannamei to chemoattractants. A diet with 3% fishmeal was supplemented with either 3% salmon meal (POS), 3% soy protein concentrate (NEG), 3% krill meal (KRM), 3% squid meal (SQM), 3% shrimp head meal (SHM), 3% shrimp meal (SM), 3% squid liver meal (SLM), or 5% liquid sardine hydrolysate (SAH). Shrimp with a body weight (BW) of 0.99 ± 0.08 g were stocked at 100 animals/m2 in 56 tanks of 1 m3 and fed 10 times daily for 74 days. Feed preference was evaluated by feeding shrimp of 10.87 ± 1.82 g in excess twice a day for 10 days in two separate feeding trays allocated in 50 tanks of 0.5 m3. Survival reached 93.3 ± 5.80% and was unaffected by supplementation. Final BW was the highest for shrimp fed the KRM‐supplemented diet (11.97 ± 0.93 g), followed by POS (11.11 ± 0.77 g) and SQM (11.01 ± 1.17 g). Diets SHM, SM, SLM, and NEG showed a lower shrimp BW than POS, but were not statistically different among them. Shrimp fed the SAH diet achieved the lowest BW (10.06 ± 1.02 g). The highest gained yield was obtained with diets KRM and POS. No statistical difference was observed in shrimp yield among other diets. The lowest feed conversion ratio (FCR) was achieved with shrimp fed KRM (1.31 ± 0.05) when compared to diets SHM (1.47 ± 0.05), SAH (1.47 ± 0.07), and SLM (1.45 ± 0.17). Two‐by‐two comparisons indicated that shrimp preferred SHM and KRM, except when these were compared to SQM and SLM. No difference in feed preference was found between diets with SQM and SLM. SAH was the least preferred raw material in all comparisons. Results indicated that KRM acts as a powerful feeding effector and growth enhancer in fishmeal‐challenged diets for whiteleg shrimp. A dietary supplementation with 3% KRM is more effective than the same dose of any other chemoattractant evaluated. 相似文献
133.
Piero ADDIS Alberto ANGIONI Viviana PASQUINI Angelica GIGLIOLI Valeria ANDREOTTI Stefano CARBONI Marco SECCI 《Integrative zoology》2021,16(2):138-148
Mussels close their shell as a protective strategy and the quantification of this behavioral marker may represent an alarm signal when they are exposed to environmental stressors. In the present study, we investigated the ability of the Mediterranean mussel Mytilus galloprovincialis to recover and then the resilience or inertia of valve activity after a pulsing exposition to diverse levels of salinity (5, 10, 20, and 35 PSU as reference value). The trial simulated an event of drastic and sudden reduction of seawater salinity thus mimicking an event of flash flood from intense rain. Valve gaping and movements were measured in continuous cycle for 10 days using a customized magneto-electric device which uses Hall sensors. Results showed that under normal conditions of salinity (35 PSU), the general pattern of valve movements was a continuously open state with sporadic spikes indicating a closing motion. At salinity of 5, PSU mussels reacted by closing their valves, leading to a 77% mortality on the 4th day. At salinity of 10, PSU animals were observed with closed valves for the entire duration of the exposure and no mortality occurred, they showed a significant reduction in the valve activity once the reference value of salinity was re-established. In contrast, salinity of 20 PSU did not trigger a significant behavioral response. Interestingly, there no define rhythms of valve movements were recorded during salinity challenges. 相似文献
134.
135.
Severe hyperkalemia presenting with wide‐complex tachycardia in a puppy with acute kidney injury secondary to leptospirosis
下载免费PDF全文
![点击此处可从《Journal of Veterinary Emergency and Critical Care》网站下载免费的PDF全文](/ch/ext_images/free.gif)
136.
Rita M. Hanel DVM DACVIM DACVECC Lee Palmer DVM MS DACVECC NREMT‐T WEMT CCRP Janice Baker DVM DACVPM Jo‐Anne Brenner BA EMT‐I EMT‐T David Dorman DVM PhD DABVT John C. Gicking DVM DACVECC Brian Gilger DVM MS DACVO DABT Cynthia M. Otto DVM PhD DACVECC DACVSMR Elizabeth Rozanski DVM DACVECC DACVIM Brian Trumpatori DVM 《Journal of Veterinary Emergency and Critical Care》2016,26(2):166-233
137.
Thromboelastographic assessment of the contribution of platelets and clotting proteases to the hypercoagulable state of dogs with immune‐mediated hemolytic anemia
下载免费PDF全文
![点击此处可从《Journal of Veterinary Emergency and Critical Care》网站下载免费的PDF全文](/ch/ext_images/free.gif)
138.
139.
Nutritional analysis and microbiological evaluation of commercially available enteral diets for cats
下载免费PDF全文
![点击此处可从《Journal of Veterinary Emergency and Critical Care》网站下载免费的PDF全文](/ch/ext_images/free.gif)
140.