全文获取类型
收费全文 | 2931篇 |
免费 | 161篇 |
国内免费 | 34篇 |
专业分类
林业 | 108篇 |
农学 | 151篇 |
基础科学 | 39篇 |
512篇 | |
综合类 | 450篇 |
农作物 | 395篇 |
水产渔业 | 192篇 |
畜牧兽医 | 1071篇 |
园艺 | 36篇 |
植物保护 | 172篇 |
出版年
2022年 | 63篇 |
2021年 | 72篇 |
2020年 | 54篇 |
2019年 | 76篇 |
2018年 | 75篇 |
2017年 | 78篇 |
2016年 | 73篇 |
2015年 | 96篇 |
2014年 | 111篇 |
2013年 | 142篇 |
2012年 | 163篇 |
2011年 | 194篇 |
2010年 | 105篇 |
2009年 | 93篇 |
2008年 | 158篇 |
2007年 | 171篇 |
2006年 | 118篇 |
2005年 | 120篇 |
2004年 | 101篇 |
2003年 | 100篇 |
2002年 | 85篇 |
2001年 | 59篇 |
2000年 | 67篇 |
1999年 | 57篇 |
1998年 | 19篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1995年 | 14篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 25篇 |
1991年 | 34篇 |
1990年 | 36篇 |
1989年 | 28篇 |
1988年 | 23篇 |
1987年 | 31篇 |
1986年 | 27篇 |
1985年 | 28篇 |
1984年 | 20篇 |
1983年 | 19篇 |
1979年 | 20篇 |
1978年 | 12篇 |
1977年 | 19篇 |
1974年 | 18篇 |
1973年 | 23篇 |
1972年 | 18篇 |
1971年 | 14篇 |
1970年 | 18篇 |
1969年 | 19篇 |
1968年 | 12篇 |
排序方式: 共有3126条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
Young BC Strom AM Prittie JE Barton LJ 《Journal of the American Veterinary Medical Association》2007,231(1):74-78
CASE DESCRIPTION: 2 dogs were evaluated because of vomiting and lethargy (a Toy Poodle; dog 1) and acute respiratory distress, vomiting, and anorexia (a Chihuahua; dog 2). Dog 1 had been exposed to a commercial hydrocarbon waterproofing spray 24 hours before the development of clinical signs, and dog 2 was examined 18 hours after exposure to a waterproofing spray containing heptane, a highly flammable liquid hydrocarbon. CLINICAL FINDINGS: In both dogs, major gastrointestinal tract abnormalities were ruled out but respiratory status worsened. Thoracic radiography revealed a diffuse interstitial pulmonary pattern, and hypoxemia was detected. TREATMENT AND OUTCOME: Hospitalization for monitoring and care was required for both dogs. The dogs recovered with supportive care, which included administration of oxygen, fluids, and bronchodilators. Additionally, dog 1 received glucocorticoids via inhalation and supplemental enteral nutrition, whereas dog 2 was treated with an antimicrobial. CLINICAL RELEVANCE: The dogs of this report developed hydrocarbon pneumonitis following exposure to waterproofing sprays. Such sprays contain potentially toxic hydrocarbons. The severity of the adverse effects associated with exposure may have been amplified because the dogs were physically small and were exposed to a relatively large amount of aerosolized spray within small areas. Development of chemical pneumonitis in pet animals is best prevented by application of waterproofing sprays in well-ventilated or outdoor areas from which pets have been excluded. With prolonged hospitalization and considerable monitoring and care, affected dogs can recover from these exposures. 相似文献
35.
Ritter MJ Perry RL Olivier NB Kim SY Dejardin LM 《Journal of the American Animal Hospital Association》2007,43(2):93-98
A novel technique was developed to estimate the caudal medial tibial plateau landmark in the face of osteophytosis to improve accuracy in tibial plateau angle measurements. Using this technique, tibial plateau angles were evaluated in 31 normal dogs before and 8 months after right cranial cruciate ligament transection. There was no significant difference in mean tibial plateau angle before or after induction of osteophytosis. Additionally, it was determined that 90% of dogs had a difference of =2 degrees between right and left tibial plateau angles, which was considered symmetrical. 相似文献
36.
37.
38.
BY-150型种子包衣机检测控制系统设计 总被引:1,自引:0,他引:1
包衣机在批量加工流程中需要针对供种量和进液量等重要参数进行检测,否则无法保证良好的包衣效果。为此,设计了一种包衣机检测控制系统,可实现对供种量和进液量参数信息的检测和控制。同时,需在供种量检测模块的硬件选型和电路设计中采用尽可能多的抗干扰措施保证种子质量的检测精度,在进液量检测模块的设计中通过采用主板信号控制动作启动、传感器检测电路直接控制动作结束的方式保证进液控制的稳定性,并通过液晶触摸屏为用户提供一个简单直观的人机交互方式。整个系统稳定可靠、抗干扰性好,满足预期的精度要求,包衣效果良好。 相似文献
39.
40.
Sunghee Bang Jaekyeong Kim Jiwon Oh Ji-Seok Kim Seong-Ryong Yu Stephen Deyrup Yong-Sun Bahn Sang Hee Shim 《Marine drugs》2022,20(3)
Six new β-resorcylic acid derivatives (1–5 and 7) were isolated from a halophyte-associated fungus, Colletotrichum gloeosporioides JS0419, together with four previously reported β-resorcylic acid lactones (RALs). The relative and absolute stereochemistry of 1 was completely established by a combination of spectroscopic data and chemical reactions. The structures of the isolated compounds were elucidated by analysis of HRMS and NMR data. Notably, compounds 1–3 had a β-resorcylic acid harboring a long unesterified aliphatic side chain, whereas the long aliphatic chains were esterified to form macrolactones in 4–9. Among the isolated compounds, monocillin I and radicicol showed potent antifungal activities against Cryptococcus neoformans, comparable to clinically available antifungal agents and radicicol showed weak antifungal activity against Candida albicans. These findings provide insight into the chemical diversity of fungal RAL-type compounds and their pharmacological potential. 相似文献