全文获取类型
收费全文 | 502篇 |
免费 | 32篇 |
国内免费 | 2篇 |
专业分类
林业 | 27篇 |
农学 | 6篇 |
基础科学 | 6篇 |
89篇 | |
综合类 | 61篇 |
农作物 | 25篇 |
水产渔业 | 35篇 |
畜牧兽医 | 258篇 |
园艺 | 14篇 |
植物保护 | 15篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 13篇 |
2016年 | 8篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 34篇 |
2012年 | 28篇 |
2011年 | 42篇 |
2010年 | 29篇 |
2009年 | 27篇 |
2008年 | 42篇 |
2007年 | 39篇 |
2006年 | 28篇 |
2005年 | 31篇 |
2004年 | 35篇 |
2003年 | 35篇 |
2002年 | 31篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1980年 | 2篇 |
排序方式: 共有536条查询结果,搜索用时 15 毫秒
51.
52.
Ko JC Payton ME White AG Galloway DS Inoue T 《Journal of the American Animal Hospital Association》2006,42(1):18-27
This crossover study tested the hypothesis that both diazepam and microdose medetomidine would comparably reduce the amount of propofol required to induce sedation. Four different medications, namely high-dose diazepam (0.4 mg/kg intravenously [IV]), low-dose diazepam (0.2 mg/kg IV), medetomidine (1 mug/kg IV), and placebo (0.5 mL physiological saline IV) were followed by propofol (8 mg/kg IV) titrated to a point where intubation could be performed. The effects of medetomidine were comparable to the effects of high-dose diazepam and significantly better than the effects of low-dose diazepam or placebo. Dogs in all treatment groups had transient hypoxemia, and induction and recovery qualities were similar. 相似文献
53.
54.
55.
56.
Hsu CL Lin W Seshasayee D Chen YH Ding X Lin Z Suto E Huang Z Lee WP Park H Xu M Sun M Rangell L Lutman JL Ulufatu S Stefanich E Chalouni C Sagolla M Diehl L Fielder P Dean B Balazs M Martin F 《Science (New York, N.Y.)》2012,335(6064):89-92
Lysosomal storage diseases (LSDs) are a group of heterogeneous disorders caused by defects in lysosomal enzymes or transporters, resulting in accumulation of undegraded macromolecules or metabolites. Macrophage numbers are expanded in several LSDs, leading to histiocytosis of unknown pathophysiology. Here, we found that mice lacking the equilibrative nucleoside transporter 3 (ENT3) developed a spontaneous and progressive macrophage-dominated histiocytosis. In the absence of ENT3, defective apoptotic cell clearance led to lysosomal nucleoside buildup, elevated intralysosomal pH, and altered macrophage function. The macrophage accumulation was partly due to increased macrophage colony-stimulating factor and receptor expression and signaling secondary to the lysosomal defects. These studies suggest a cellular and molecular basis for the development of histiocytosis in several human syndromes associated with ENT3 mutations and potentially other LSDs. 相似文献
57.
The study of alternatives to conventional industrial agricultural production has intensified in recent years. While many types
of alternative production systems, and the motivations of individuals to participate in them, have been studied, there are
significant gaps in the literature. One such dearth is research on those participating in self-provisioning activities. This
study begins to fill the gap by looking at the self-provisioning activity of home gardening using data from the 2008 Ohio
Survey of Food, Agriculture, and Environmental Issues. Discerning who household gardeners are is important given the recent
economic, cultural, and political climate of the United States. The results show that home gardening occurs throughout the
state of Ohio at surprisingly high levels. Bivariate and multivariate analyses reveal several noteworthy associations between
gardening and household characteristics, including spatial location, pro-environmental and economic hardship behaviors, and
level of participation in localized food systems. 相似文献
58.
RA Krimins JC Ko AB Weil ME Payton PD Constable 《American journal of veterinary research》2012,73(9):1363-1370
Objective-To evaluate hemodynamic effects in dogs after IM administration of dexmedetomidine (7.5 μg/kg, butorphanol (0.15 mg/kg), and tiletamine-zolazepam (3 mg/kg [DBTZ]) or dexmedetomidine (15 μg/kg), butorphanol (0.3 mg/kg), and ketamine (3 mg/kg [DBK]). Animals-5 healthy adult mixed-breed dogs. Procedures-Each dog received DBTZ and DBK in a randomized crossover study with a 48-hour interval between treatments. Anesthesia was induced and maintained with sevoflurane in 100% oxygen while instrumentation with Swan-Ganz and arterial catheters was performed. Following instrumentation, hemodynamic measurements were recorded at 3.54% (1.5 times the minimum alveolar concentration) sevoflurane; then sevoflurane administration was discontinued, and dogs were allowed to recover. Six hours after cessation of sevoflurane administration, baseline hemodynamic measurements were recorded, each dog was given an IM injection of DBTZ or DBK, and hemodynamic measurements were obtained at predetermined intervals for 70 minutes. Results-DBTZ and DBK induced hypoventilation (Paco(2), approx 60 to 70 mm Hg), respiratory acidosis (pH, approx 7.2), hypertension (mean arterial blood pressure, approx 115 to 174 mm Hg), increases in systemic vascular resistance, and reflex bradycardia. Cardiac output, oxygen delivery, and oxygen consumption following DBTZ or DBK administration were similar to those following sevoflurane administration to achieve a surgical plane of anesthesia. Blood l-lactate concentrations remained within the reference range at all times for all protocols. Conclusions and Clinical Relevance-In healthy dogs, both DBTZ and DBK maintained oxygen delivery and oxygen consumption to tissues and blood lactate concentrations within the reference range. However, ventilation should be carefully monitored and assisted when necessary to prevent hypoventilation. 相似文献
59.
Grace Delia Gilbert Jeff Randolph Thomas Kangethe Erastus 《Tropical animal health and production》2012,45(1):67-74
Individual interviews were conducted in 137 households using semi-structured questionnaires to determine the influence of socioeconomic factors on production constraints faced by indigenous chicken producers in the rural areas of South Africa. The major constraints to village chicken production were mortality (95 % of the households) followed by feed shortage (85 %) and low chicken sales (72 %). The logistic regression model showed that households that owned imported/crossbred chickens practiced extensive production system without housing structures and did not have vaccines were more likely to experience high levels of chicken mortality. Poor and youth-headed households with no supplements and vaccines had high probability of Newcastle disease. The probability of a household to experience chicken feed shortage was lower in households that owned indigenous chickens than those that owned imported/crossbred chickens (odds ratio, 11.68; 95 % confidence interval, 1.19–27.44). Youth-headed households that had small flocks and no access to veterinary services were not likely to sell chickens. It was concluded that gender, age, wealth status, production system, chicken flock size, type of chicken breed owned, accessibility of veterinary services, availability of supplements, vaccines and shelter influence village chicken farmer’s production constraints such as feed availability, chicken mortality, prevalence of diseases and chicken sales. 相似文献
60.