全文获取类型
收费全文 | 796篇 |
免费 | 56篇 |
专业分类
林业 | 26篇 |
农学 | 7篇 |
75篇 | |
综合类 | 250篇 |
农作物 | 22篇 |
水产渔业 | 57篇 |
畜牧兽医 | 353篇 |
园艺 | 8篇 |
植物保护 | 54篇 |
出版年
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 11篇 |
2016年 | 7篇 |
2015年 | 12篇 |
2014年 | 19篇 |
2013年 | 17篇 |
2012年 | 23篇 |
2011年 | 26篇 |
2010年 | 15篇 |
2009年 | 10篇 |
2008年 | 29篇 |
2007年 | 55篇 |
2006年 | 50篇 |
2005年 | 44篇 |
2004年 | 39篇 |
2003年 | 51篇 |
2002年 | 39篇 |
2001年 | 39篇 |
2000年 | 31篇 |
1999年 | 20篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1992年 | 23篇 |
1991年 | 12篇 |
1990年 | 19篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1972年 | 9篇 |
1971年 | 7篇 |
1970年 | 6篇 |
1969年 | 5篇 |
1966年 | 6篇 |
1948年 | 8篇 |
排序方式: 共有852条查询结果,搜索用时 31 毫秒
41.
Virucidal efficacy of four new disinfectants 总被引:5,自引:0,他引:5
Eleraky NZ Potgieter LN Kennedy MA 《Journal of the American Animal Hospital Association》2002,38(3):231-234
Virucidal efficacy was evaluated for four recently available disinfectants: chlorine dioxide, potassium peroxymonosulfate, a quaternary ammonium compound, and citricidal (grapefruit extract). Sodium hypochlorite (3%) and tap water were used as positive and negative controls respectively. Feline herpesvirus, feline calicivirus, and feline parvovirus were exposed to the manufacturers' recommended dilutions of the evaluated disinfectants. Both chlorine dioxide and potassium peroxymonosulfate completely inactivated the three viruses used in this study. These disinfectants can aid in controlling nosocomial transmission of viruses with less of the deleterious effects of sodium hypochlorite. The quaternary ammonium compound evaluated in this study and citricidal were not effective against feline calicivirus and feline parvovirus. 相似文献
42.
Monoamines are important brain neurotransmitters. An investigation was carried out to determine if hypomagnesaemic tetany was associated with alterations in regional brain monoamine concentrations in bovines. The results, established in cows with normal magnesium status, demonstrated that regional differences existed in the distribution and concentration of brain monoamines in the adult bovine, which were similar to those in other species. In magnesium-deficient cows, severe hypomagnesaemia and lowered cerebrospinal fluid (CSF) magnesium concentrations were associated with significant alterations in monoamine concentrations in some brain regions. Alterations in 3,4-dihydroxyphenylalanine (DOPA) and dihydroxyphenylacetic acid (DOPAC) concentrations in the corpus striatum, and dopamine (DA) in the cerebral cortex and cerebellum were recorded. These regions play an important role in both voluntary and involuntary motor function, and therefore these alterations may play a role in the aetiology of hypomagnesaemic tetany. However, there was no significant change in DA concentrations in the corpus striatum (the main dopaminergic region in the brain) associated with hypomagnesaemia. In addition, a significantly lower norepinephrine (NE) concentration in the corpus striatum of hypomagnesaemic animals was also recorded. Norephinephrine is generally excitatory and therefore lowered NE concentrations would be expected to result in depression rather than stimulation of motor function. 相似文献
43.
Harkin KR Kennedy GA Moore WE Schoning P 《Journal of the American Animal Hospital Association》2000,36(1):63-66
A 16-month-old, neutered male bullmastiff was presented for acute onset of massive swelling of the right hind limb. Primary skeletal muscle lymphoma was diagnosed based on cytopathology, surgical biopsy, and necropsy findings. Cutaneous metastases developed during the hospitalization, and additional metastases were found in the heart and thoracic wall. Primary skeletal muscle lymphoma is a rare form of lymphoma in dogs and should be considered as a differential diagnosis for acute, soft-tissue swelling of the limb. 相似文献
44.
The effects of field aging (0–28 days) and pheromone loading rate on the longevity of red rubber septa loaded with the sex
pheromone blend of the oriental fruit mothGrapholita molesta (Busck), were evaluated in North Carolina apple orchards in 2002. Separate field tests examined the influence of trap height
and pheromone loading rate of rubber septa on trap catches of adultG. molesta males in an abandoned orchard. The loss of the major pheromone component, (Z)-8-dodecenyl acetate (Z8–12:OAc), from red rubber
septa over a 4-week period exhibited a relatively constant release rate with 30, 100 and 300 μg pheromone. Trap catch was
significantly higher in pheromone traps placed in the upper canopy than in those in the lower canopy. Pheromone traps baited
with 100μg lures caught more moths compared with those loaded with 300 μg. There was no apparent relationship between pheromone
trap catch and septa age, with trap catch appearing to be primarily a function ofG. molesta population density.
http://www.phytoparasitica.org posting May 14, 2006. 相似文献
45.
An 8-yr-old male tayra (Eira barbara) was presented with acute onset of pelvic limb paralysis. Radiography was unremarkable. Neurologic examination showed signs consistent with an intramedullary lesion between the second thoracic and fifth lumbar spinal cord segments. The animal's condition did not improve after 4 days of aggressive glucocorticoid therapy, and euthanasia was performed. Histologic examination of the spinal cord showed amorphous emboli suggestive of cartilaginous fragments within spinal veins. A diagnosis of fibrocartilaginous emboli was made, the first known case in a mustelid. 相似文献
46.
47.
48.
To determine the effect of shade on morphology, growth and biomass allocation in Picea sitchensis, Larix × eurolepis and Thuja plicata, seedlings were grown in the open or under shadehouses providing 25%, 50% and 75% reductions of full-light for two growing
seasons. For most of the characteristics assessed there was no significant interaction between species and shade indicating
that the morphological responses to changing shade treatments were not species-dependent. After two growing seasons the mean
height increment for the three species was significantly greater in 25% (76.1 cm) and 50% shade (74.9 cm) than in the open
(69.5 cm). Root collar diameter increment, shoot, root and total biomass declined significantly with increasing shade while
the opposite was true for the height:diameter ratio. In both western red cedar and hybrid larch the shoot:root ratio was significantly
greater in the shade while in Sitka spruce this characteristic was not influenced by shade. While all species had significantly
greater specific shoot areas in 75% shade than in 0% shade, this trend was particularly pronounced in hybrid larch. In hybrid
larch and western red cedar, the normalised specific projected shoot area increased significantly with increasing shade. The
opposite trend was observed for Sitka spruce. We conclude that in the main the species studied demonstrated similar shade
acclimation responses despite their reported differences in shade tolerance. 相似文献
49.
50.