全文获取类型
收费全文 | 293篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
林业 | 7篇 |
农学 | 12篇 |
基础科学 | 1篇 |
24篇 | |
综合类 | 20篇 |
农作物 | 14篇 |
水产渔业 | 27篇 |
畜牧兽医 | 187篇 |
植物保护 | 7篇 |
出版年
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 15篇 |
2011年 | 22篇 |
2010年 | 12篇 |
2009年 | 12篇 |
2008年 | 9篇 |
2007年 | 21篇 |
2006年 | 21篇 |
2005年 | 23篇 |
2004年 | 16篇 |
2003年 | 28篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 15篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1975年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有299条查询结果,搜索用时 15 毫秒
41.
Estrous expressions in dairy cows have been shortened and weakened. Dairy heifers, on the other hand, may not have had such changes in estrous signs as observed in cows, since they have less stresses than cows. The aim of this study was to describe the duration of estrus in a herd of dairy heifers. A total of 56 Holstein Friesian heifers estrus was synchronized using two different hormonal protocols. They were checked for primary and secondary estrous signs with the help of heat detection devices for 48 h at an interval of 4 h starting at 16.00 hour, one day after PGF2α treatment. Onset and end of standing estrus during 48 h observation period was recorded in 35 of the 44 heifers coming into estrus within 5 days after PGF2α treatment during the observation period. The duration of standing estrus on the average (±SD) was 9.7 ± 5.3 h. Percentage of heifers with standing estrus longer than 12 h was 40%, and 53% showed standing estrus only for 4–8 h. It is indicated that duration of estrus in dairy heifers has been shortened recently. 相似文献
42.
43.
Koiwai M Hamaoka T Haritani M Shimizu S Zeniya Y Eto M Yokoyama R Tsutsui T Kimura K Yamane I 《Veterinary parasitology》2006,135(2):175-179
Serum samples from 2420 clinically healthy dairy cattle, randomly selected from stored sera in 18 districts of Japan, were tested for the presence of Neospora caninum antibodies using an indirect fluorescent antibody test (titer > or =1:200). Nationwide seroprevalence is estimated at 5.7% (139/2420). Seropositive cattle were detected in all surveyed districts despite the evidence of confirmed case reports of bovine neosporosis, showing that N. caninum is widely distributed throughout Japan. Age-specific seroprevalence did not increase with cattle age, suggesting that Neospora infection is likely to be transmitted vertically rather than horizontally in Japan. Considering that N. caninum seropositive cows are thought to be more likely to abort, substantial fetal losses may be induced by N. caninum infection in Japan. Devising strategies are needed to reduce the economic impact on the Japanese dairy industry. This is the first study to investigate the nationwide seroprevalence of N. caninum in cattle in Asia. 相似文献
44.
The beneficial effects of horse trekking on autonomic nervous activity in experienced rider with no disability
下载免费PDF全文
![点击此处可从《Animal Science Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Akihiro Matsuura Haruhiro Maruta Tomohiko Iwatake Takashi Kumagai Toshihiko Nakanowatari Koichi Hodate 《Animal Science Journal》2017,88(1):173-179
The aim of this study was to determine whether autonomic nervous activity of a rider with no disability was altered by one practical and applicable horse trekking (HT) exercise. Changes in autonomic nervous activity were analyzed by heart rate variability (HRV). Twenty‐three participants with no disability rode horses along a predetermined HT course at trotting and walking for 60 min. HRV was sampled at 60 min before and immediately, following 60 min, and 120 min after HT. As a control, the same measurements were performed for 22 age‐matched participants during their rest. Only in the HT group, the value of normalized unit in high frequency component (HF nu), an index of parasympathetic nervous activity, was higher at 120 min after treatment than before HT (P < 0.05). The low / high frequency ratio (LF / HF), believed to reflect sympathetic nervous activity, was lower in the HT group than those in the control group at 60 min (P < 0.05) and 120 min after treatment (P < 0.01). These findings suggest that a single HT shifted the autonomic nervous balance of a rider toward parasympathetic dominance. The results obtained by the present study could accelerate the use of horses for human health. 相似文献
45.
46.
Junichiro Takeuchi Toshihiko Kawachi Chie Imagawa Natsuki Buma Koichi Unami Shigeya Maeda 《Paddy and Water Environment》2010,8(2):145-156
A sophisticated modeling approach for simulating-coupled surface and subsurface flows in a watershed is presented. The watershed
model developed is a spatially distributed physically based model of composite dimension, consisting of 3-D variably saturated
groundwater flow submodel, 2-D overland flow submodel and 1-D river flow submodel. The 3-D subsurface flow is represented
by the complete Richards equation, while the 2-D and 1-D surface flows by the diffusive approximations of their complete dynamic
equations. For piecewise integration of these equations, the finite volume method (FVM) is employed assuming unknown variables
such as the water depth and the pressure head to be volume-averaged state ones. Problem plane geometry is meshed with the
unstructured cells of triangular shape which conforms to external as well as internal irregular boundaries such as those between
1-D and 2-D flows. A cell size controlling scheme, referred to as quasi-adaptive meshing scheme, is introduced to keep the
local discretization errors caused by topographic elevation gradient even over the entire-meshed geometry. Performance of
the model is tested through its practical application to a rugged intermountain watershed. Tuning the values of the three
key parameters ensures successful calibration of the model. Once the model is so calibrated, it could reproduce satisfactory
runoff response to any rainfall event. Expansion and shrinkage of the contributing area importantly affecting the direct runoff,
caused by the vicissitude of rainfall during its total duration, are well reproduced, like what the commonly accepted runoff
theory argues. It is thus concluded that the model developed could serve as a powerful watershed simulator usable for investigating
and assessing the hydrological aspect of a watershed. 相似文献
47.
Abe N Okuhira M Tsutsui C Murata Y Nakamura Y 《Journal of agricultural and food chemistry》2012,60(7):1887-1892
In the present study, we examined the toxicity of benzyl ITC (BITC) and its urinary mercapturic acid metabolite (BITC-NAC), using a normal renal proximal tubular cell line, pig LLC-PK1. BITC increased cell death with an IC(50) value of about 7 μM, whereas the cytotoxic effect of BITC-NAC was five times weaker than that of BITC. We observed a significant necrosis of the compounds on LLC-PK1 cells with oxidative stress. In the presence of 5 mM glutathione (GSH), comparable to physiological levels, the cytotoxicity of BITC-NAC as well as BITC was significantly reduced. Furthermore, the increase in intracellular GSH levels by pretreatment with NAC before the BITC treatment resulted in inhibition of the BITC-induced necrotic events as well as intracellular oxidative stress. These results suggest that GSH is a determinant of cellular resistance against the BITC-mediated and oxidative stress-dependent cytotoxicity in renal proximal tubular cells. 相似文献
48.
Toyonaga M Kaihara A Tsutsui T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(10):1395-1398
On the assumption that animals of wild feline species died in the field, caudal epididymal sperm were cryopreserved following storage of the feline epididymides at 20°C for 0-24 hr, and their qualities were observed. Compared to the qualities at 0 hr, no significant differences were noted following 12 hr of storage at 20°C. On comparison of the qualities between caudal sperm cryopreserved after 24 hr storage at 4°C and after 12 hr at 20°C followed by 12 hr storage at 4°C, no significant differences were noted. These findings suggest that the cryopreserved sperm collected from epididymides of dead animals might be useful for artificial insemination if cryopreservation was performed within 12 hr exposure to ambient temperature. 相似文献
49.
Hori T Matsuda Y Kobayashi M Kawakami E Tsutsui T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(12):1685-1688
The fertility was compared between ejaculated and cauda epididymal sperm sensitized with prostatic fluid in dog after freeze-thawing using the fertility of ova from the contralateral ovary after injection (2 × 10(8) sperm) into dog uterus on the unilateral ovariectomized side, on the basis of the presence or absence of conception. No significant difference was observed in sperm quality after freeze-thawing between the two groups and conception rates were equivalent and low. Therefore, to achieve a high fertility by intrauterine insemination of canine frozen-thawed ejaculated and cauda epididymal sperm, intrauterine insemination on both sides is recommended, rather than insemination with a lot of sperm of the uterine horn on one side. 相似文献
50.
Shigeya Maeda Toshihiko Kawachi Koichi Unami Junichiro Takeuchi Tomoki Izumi Syunsuke Chono 《Paddy and Water Environment》2009,7(3):163-175
A fuzzy optimization model is developed to allocate allowable total nitrogen (T-N) loads to distributed nonpoint sources (NPSs)
and point sources (PSs) in a watershed for river water quality management using the linear programing technique. The watershed
is divided into uniform grid cells on which T-N loads issuing from NPSs such as paddy fields, upland crop fields and cities
are controlled. A geographic information system integrated with the digital elevation model facilitates computation of route
lengths of surface and subsurface flows from cells to a river running through the watershed. The T-N loads discharged from
their sources are assumed to decay, subject to distance-related first-order kinetics. As management goals, maximizations of
total allowable NPS loads, total allowable PS loads and total yield of rice are considered from environmental and economic
viewpoints. A prime constraint is an effluent limitation standard for the aggregate amount of loads that arrive at the downstream
end of the river. The fuzzy sets theory helps appropriately describe vague attitudes of decision-makers (i.e., stakeholders
and management authorities) in terms of constraints and conflicting goals. An application of the fuzzy optimization model,
developed as an improvement over our last nonfuzzy model, to a real watershed in Shiga prefecture, Japan, demonstrates that
the fuzzy model embodies our last model, and is capable of creating management alternatives for T-N load allocation in a more
practical and flexible manner. 相似文献