全文获取类型
收费全文 | 477篇 |
免费 | 9篇 |
专业分类
林业 | 30篇 |
农学 | 21篇 |
基础科学 | 2篇 |
33篇 | |
综合类 | 26篇 |
农作物 | 18篇 |
水产渔业 | 101篇 |
畜牧兽医 | 201篇 |
园艺 | 4篇 |
植物保护 | 50篇 |
出版年
2022年 | 7篇 |
2021年 | 17篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 28篇 |
2011年 | 34篇 |
2010年 | 20篇 |
2009年 | 19篇 |
2008年 | 31篇 |
2007年 | 18篇 |
2006年 | 18篇 |
2005年 | 29篇 |
2004年 | 19篇 |
2003年 | 33篇 |
2002年 | 19篇 |
2001年 | 24篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1974年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有486条查询结果,搜索用时 15 毫秒
61.
ParikesitEmail author K.?Takeuchi A.?Tsunekawa O.?S.?Abdoellah 《Agroforestry Systems》2005,63(2):171-182
A comprehensive study was carried out on a typical indigenous agroforestry system, called kebon tatangkalan, in the changing agricultural landscape of the Upper Citarum Watershed, West Java, Indonesia. The main objectives of the study are to elucidate the structural patterns, multidimensional functions, and dynamics of this multi-layered agroforest. The study has identified 12 groups of different plant assemblages indicating that this type of agroforest contributes considerably to the heterogeneity of the agricultural landscape in the study area. Multivariate analysis suggests that elevation and slope are the biophysical factors that correlate most significantly with the distribution of plant species in kebon tatangkalan. The presence of this man-made vegetation is currently declining from the landscape due to population growth and rapid regional economic development. Serious effort to revitalize this traditional agroforest is needed to prevent its disappearance. Introduction of highly productive species and establishment of integrated policies in regional land-use planning and management are measures that should be taken into account in preserving this traditional agroforestry system. 相似文献
62.
The optimal water temperature in seed germination and the upper critical water temperature in seedling growth were determined
for Zostera japonica collected from Ago Bay, Japan. The relationship between the seed germination rates and seed storage period (0, 30, and 60 days)
at 0°C was also examined. The optimal water temperature in seed germination was in the range 15–20°C regardless of the storage
period, in which germination rates were up to 14%. Seedlings, grown from seeds up to 10 cm in total length, were cultured
for 1 week at various water temperatures to measure their relative growth rates. The optimal water temperature in early growth
was in the range 20–25°C; relative growth rates ranged from 3.8 to 4.2%. Seedlings could survive up to a water temperature
of 29°C, but most seedlings withered at 30 or 35°C.
The optimal water temperatures for seed germination and seedling growth were related to the seasonal changes of water temperature
in the sampling site. Although seedlings were hardly observed in Ago Bay in summer, Z. japonica might extend its distribution as far as where the summer water temperature is lower than 29°C. 相似文献
63.
Eastern little tuna,Euthynnus affinis (Cantor, 1849) mature and reproduce within 1 year of rearing in land‐based tanks 下载免费PDF全文
Ryosuke Yazawa Yutaka Takeuchi Kenta Satoh Yuri Machida Kotaro Amezawa Naoki Kabeya Yukinori Shimada Goro Yoshizaki 《Aquaculture Research》2016,47(12):3800-3810
Eastern little tuna (ELT, Euthynnus affinis) is expected to see use as a novel aquaculture species due to its rapid growth and high economic value. In this study, closing of the complete life cycle of ELT in land‐based tanks was successfully carried out. Seed production of a first generation (F1) derived from wild‐caught ELT broodstock was conducted in 2010, 2011 and 2012. Survival percentages of F1 ELT at 365 days post hatching for the 2010, 2011 and 2012 year classes were 0.9%, 0.4% and 6.3% respectively. On average, F1 ELT were approximately 40 cm in total length and weighed 1500 g by the time they reached 1 year of age. Successful artificial induction of spawning was achieved in 1‐year‐old F1 ELT using a gonadotropin‐releasing hormone analogue (GnRHa). Induction of spawning was successful at the first administration of GnRHa in the 2010, 2011 and 2012 year classes. First spawning was observed at 4 or 5 days post implantation, which indicated that oogenesis and spermatogenesis progressed within 1 year of rearing in land‐based tanks. During spawning periods, the average number of fertilized eggs and the average number of hatched larvae per spawning event in the 2010, 2011 and 2012 year classes were 20,480 eggs day?1 and 177 larvae day?1, 39,423 eggs day?1 and 9347 larvae day?1, and 819,555 eggs day?1 and 674,445 larvae day?1 respectively. Therefore, it was concluded that both male and female ELT reared in land‐based tanks were capable of reproduction at 1 year of age. 相似文献
64.
65.
Chung Sarit Takeuchi Junichiro Fujihara Masayuki Oeurng Chantha 《Paddy and Water Environment》2019,17(2):255-263
Paddy and Water Environment - In Cambodia, rice production is important for the majority of rural populations as the main source of income. However, historical extreme flood events, especially the... 相似文献
66.
Kakuma Y Ichimaru T Yonezawa T Momozawa Y Hashizume C Iwata E Kikusui T Takeuchi Y Ohkura S Okamura H Mori Y 《The Journal of reproduction and development》2007,53(4):829-834
Previously we showed that the primer pheromone responsible for the "male effect" was produced in specific skin regions of castrated male goats by androgen treatments. In the present study, we examined whether androgen can also induce production of the male effect pheromone in female goats. Capsules containing dihydrotestosterone (DHT) or testosterone (T) were subcutaneously implanted into six ovariectomized (OVX) goats for 28 days. Small skin samples were collected from the head and rump regions, and the pheromone activity of their ether extracts was examined using a bioassay that monitors the electrophysiological manifestation of the hypothalamic gonadotropin-releasing hormone pulse generator as multiple-unit activity. Behaviors of OVX goats towards ovary-intact estrous goats were also examined before and at the end of DHT or T treatment. Before androgen treatment, neither the head nor rump skin samples in OVX goats showed pheromone activity. DHT treatment induced pheromone activity in the head skin sample of six OVX goats and in the rump skin sample of two OVX goats. Similar results were obtained by T treatment. In addition, OVX goats treated with T showed masculine-type sexual behaviors such as courtship and mounting behaviors towards the estrous goats. These results demonstrate that androgen is capable of inducing primer pheromone activity in the female and suggest that the synthesis pathway of the male effect pheromone exists in both sexes in the goat. 相似文献
67.
68.
Proteolytic zymograms of Staphylococcus hyicus subsp. hyicus isolated from pigs, chickens and cows 总被引:1,自引:0,他引:1
The extracellular proteases of Staphylococcus hyicus subsp. hyicus were assayed by a zymogram showing caseinolysis and gelatinolysis. Four bands were associated with caseinolysis or with gelatinolysis. The patterns shown by strains isolated from pigs, chickens and cows were compared; isolates from pigs differed from those isolated from chickens or cows but strains isolated from diseased and healthy pigs could not be differentiated. 相似文献
69.
T. Morita A. Shimada T. Takeuchi Y. Hikasa M. Sawada S. Ohiwa M. Takahashi N. Kubo T. Shibahara H. Miyata E. Ohama 《Canadian journal of veterinary research》2002,66(1):35-41
We examined an epileptic focus by electroencephalography (EEG) by using an international 10-20 electrode system in 11 Shetland sheep dogs affected with familial idiopathic epilepsy. We also performed an evaluation of the amino acids in the cerebrospinal fluid (CSF) and a pathologic examination of the brains of 8 dogs that died from status epilepticus. Continuous electroencephalography demonstrated that an epileptic focus was initially detected in the frontal lobe, particularly the internal area, and that paroxysmal foci developed diffusely in other lobes of affected dogs with recurrent convulsions. The EEG analyses indicated spike and sharp wave complexes, which were considered to be paroxysmal discharges. An increased value for glutamate or aspartate was found in the CSF of some epileptic dogs. Histologically, acute neuronal necrosis and astrocytosis were distributed predominantly in the cingulate cortex and internal area of frontal cortex, less frequently in other areas of the cerebrum. The results of this study suggest that, initially, the dogs have an epileptic focus in the frontal lobe, and that the focus extends gradually to other areas of the cerebrum. Based on the distribution of neuronal necrosis and astrocytosis, acute neuronal damage may be related to the superexcitation of neurons following epilepsy. 相似文献
70.
Yokoyama T Etoh T Udayanga KG Takahara E Qi WM Warita K Matsumoto Y Miki T Takeuchi Y Hoshi N Kitagawa H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(7):949-952
The hypothesis that apoptotic factors play some roles in the denucleation of erythroblasts has been confirmed by the immunohistological detection of both phosphatidylserine and thrombospondin as phagocytosis-inducing factors in general apoptotic events. Both phosphatidylserine and thrombospondin were detected on the surface of cell membrane of mature erythroblasts, while thrombospondin was also detected in more immature erythroblasts. The intensities of their immune reactions increased as the erythroids matured. During denucleation, the positivities of both phosphatidylserine and thrombospondin were restricted on the surface of the cell membrane surrounding the protruding nuclei. Thus, the apoptotic process involves denucleation of erythroblasts and phosphatidylserine, and thrombospondin acts as phagocytosis-inducing factors in the denucleation event. 相似文献