全文获取类型
收费全文 | 661篇 |
免费 | 32篇 |
国内免费 | 1篇 |
专业分类
林业 | 55篇 |
农学 | 33篇 |
基础科学 | 8篇 |
110篇 | |
综合类 | 96篇 |
农作物 | 36篇 |
水产渔业 | 53篇 |
畜牧兽医 | 230篇 |
园艺 | 19篇 |
植物保护 | 54篇 |
出版年
2023年 | 8篇 |
2022年 | 4篇 |
2021年 | 14篇 |
2020年 | 19篇 |
2019年 | 27篇 |
2018年 | 12篇 |
2017年 | 31篇 |
2016年 | 22篇 |
2015年 | 17篇 |
2014年 | 27篇 |
2013年 | 43篇 |
2012年 | 37篇 |
2011年 | 62篇 |
2010年 | 44篇 |
2009年 | 14篇 |
2008年 | 35篇 |
2007年 | 42篇 |
2006年 | 26篇 |
2005年 | 24篇 |
2004年 | 27篇 |
2003年 | 29篇 |
2002年 | 25篇 |
2001年 | 4篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1997年 | 6篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1941年 | 1篇 |
1931年 | 2篇 |
1919年 | 1篇 |
1911年 | 2篇 |
排序方式: 共有694条查询结果,搜索用时 15 毫秒
51.
Vincent Marolf Helene Rohrbach Géraldine Bolen Anne-Sophie Van Wijnsberghe Charlotte Sandersen 《Veterinary anaesthesia and analgesia》2019,46(1):106-115
Objective
To develop a modified ultrasound-guided parasacral approach to the sciatic nerve and compare the effects of a volume of 0.2 mL kg–1 of 0.5% levobupivacaine with an equivalent volume of 0.9% saline injected near the sciatic nerve.Study design
Cadaveric and experimental, blinded, randomized study.Animals
Seven canine cadavers and seven experimental Beagle dogs.Methods
Both sciatic nerves of seven cadavers were identified using a modified in-plane ultrasound-guided approach. Methylene blue solution (0.2 mL) was injected perineurally, and success was evaluated through dissection. The same approach was repeated in seven Beagle dogs sedated with dexmedetomidine (50 μg kg–1) injected intramuscularly (IM). After randomization, 0.2 mL kg–1 of 0.5% levobupivacaine (limb L) and 0.2 mL kg–1 of 0.9% saline (limb C) were injected perineurally on either right or left limb. Block success was determined by sensory deficits every hour for 8 hours after an atipamezole injection (0.2 mg kg–1) IM. Reaction to pinprick (binary score) over the course of the sciatic nerve (four locations) and locomotion were assessed.Results
The overall sciatic nerve block success was 93% in cadavers and 86% in sedated dogs. It was impossible to localize the sciatic nerves in one obese sedated dog. Significant differences between limb L and limb C were observed for pinprick at great trochanter, caudal thigh and lateral tarsal joint (p < 0.0001). Reaction to pinprick was absent in all dogs at great trochanter and caudal thigh up to at least 3 hours on limb L. Locomotion was impaired in all but one dog for 60 (30–210) minutes (median; interquartile range). No complications were observed.Conclusions and clinical relevance
A volume of ≥0.2 mL kg–1 and a concentration of 0.5% levobupivacaine can be recommended when using a modified ultrasound-guided parasacral approach to the sciatic nerve in dogs. 相似文献52.
53.
54.
Fertility of cattle following PGF2 alpha injection 总被引:4,自引:0,他引:4
55.
56.
Effects of treadmill exercise on the transfer of plasma triglyceride into the ovary of the laying fowl 总被引:1,自引:1,他引:0
1. The effects of 90 min continuous treadmill exercise on the plasma-to-ovary transfer of 14C-labelled triglycerides in laying hens were examined. 2. Exercised birds showed a 4-fold increase in plasma free fatty acid concentration, a 15% decrease in plasma glucose concentration and unchanged plasma triglyceride concentration compared with resting controls. The mean plasma-to-ovary triglyceride transfer rate was approximately halved by exercise. 3. The surface area-specific triglyceride transfer rate was greatest for oocytes weighing 0.25-1.5 g and decreased with increasing oocyte size. The lowest rates were in the small (less than 0.25 g) white oocytes. This pattern was largely unaffected by exercise. 4. Factors that might be responsible for the reduction in triglyceride transfer into the oocytes during exercise include hormonal effects on the permeability of the oocyte envelope, increased competition for plasma lipids by the working muscles and reduced blood flow to the ovary, as a result of the release of vasoconstrictors. 相似文献
57.
A comparison of three micro-assay detection systems for naturally occurring and experimentally induced rat antibody to Mycoplasma pulmonis was performed. The micro-enzyme linked immunoabsorbent assay was found superior to counter immunoelectrophoresis or complement fixation techniques when comparing sensitivity, duration of antibody response, or technical requirements. The primary immune response was routinely detected at 3 weeks after antigen exposure when using the enzyme linked or complement fixation assays. 相似文献
58.
59.
BACKGROUND: In pest management research, harmonic radar systems have been largely used to study insect movement across open or vegetation‐poor areas because the microwave signal is attenuated by the high water content of vegetation. This study evaluated whether the efficacy of this technology is sufficient to track insects in vegetative landscapes. RESULTS: Field efficacy data were collected using portable harmonic microwave radar and electronic dipole tags mounted on adults of three economically important pests: Leptinotarsa decemlineata (Say), Diabrotica virginifera virginifera (LeComte) and Conotrachelus nenuphar Herbst. Detection and recovery of tagged Colorado potato beetles, plum curculios and western corn rootworms was high within and among potato plants, moderate within apple trees and high within, but not between, corn plants respectively. The efficacy of the radar depends on the ability of the operator to move around the host, scanning for a signal ‘sightline’ with the tagged insect among plant structures. CONCLUSION: The detection rate of tagged insects by harmonic radar systems is high enough to track the walking path of pests through low row crops such as potato, tall row crops such as corn or tall but well‐separated trees of orchard‐type crops by adapting the scanning procedure to the vegetative architecture. Copyright © 2010 Crown in the right of Canada. Published by JohnWiley & Sons, Ltd 相似文献
60.
Chorfi Y Girard V Fournier A Couture Y 《The Canadian veterinary journal. La revue veterinaire canadienne》2011,52(10):1089-1094
This study measured the effect on glutathione peroxidase (GSH-Px) and selenium (Se) in whole blood and plasma associated with subcutaneous Se injections in beef heifers fed organic or inorganic Se. Heifers (n = 120) were randomly divided into 2 groups, 1 of which received subcutaneous Se injections. Both groups were given the same total mixed ration with 3 mg of organic or inorganic Se daily. Until week 2, heifers that had received Se injections showed higher concentrations of plasma Se and GSH-Px and whole blood Se (P < 0.001) than those having had no injections. Concentrations of plasma Se and GSH-Px were higher in the group receiving organic Se than the group receiving inorganic Se. Whole blood GSH-Px concentrations increased significantly (P < 0.001) throughout a 12-week period but were not affected by Se source. Combination of Se injections and supplementation could help maintain normal Se and GSH-Px blood status in beef heifers during the first few weeks in the feedlot. 相似文献