全文获取类型
收费全文 | 361篇 |
免费 | 23篇 |
国内免费 | 1篇 |
专业分类
林业 | 15篇 |
农学 | 7篇 |
39篇 | |
综合类 | 19篇 |
农作物 | 18篇 |
水产渔业 | 69篇 |
畜牧兽医 | 158篇 |
园艺 | 3篇 |
植物保护 | 57篇 |
出版年
2022年 | 4篇 |
2021年 | 16篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 15篇 |
2017年 | 14篇 |
2016年 | 12篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 22篇 |
2012年 | 17篇 |
2011年 | 23篇 |
2010年 | 19篇 |
2009年 | 16篇 |
2008年 | 28篇 |
2007年 | 26篇 |
2006年 | 24篇 |
2005年 | 26篇 |
2004年 | 13篇 |
2003年 | 21篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有385条查询结果,搜索用时 0 毫秒
101.
102.
Okada H Iwamaru Y Imamura M Masujin K Matsuura Y Shimizu Y Kasai K Takata M Fukuda S Nikaido S Fujii K Onoe S Mohri S Yokoyama T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(11):1465-1471
Bovine spongiform encephalopathy (BSE) is a fatal neurodegenerative disorder of cattle characterized by accumulation of the disease-associated prion protein (PrP(Sc)) in the central nervous system (CNS). The immunohistochemical patterns and distribution of PrP(Sc) were investigated in the CNS, brains, and spinal cords of 7 naturally occurring BSE cases confirmed by the fallen stock surveillance program in Japan. No animals showed characteristic clinical signs of the disease. Coronal slices of 14 different brain areas in each case were immunohistochemically analyzed using an anti-prion protein antibody. Immunolabeled PrP(Sc) deposition was widely observed throughout each brain and spinal cord. Intense PrP(Sc) deposition was greater in the thalamus, brainstem, and spinal cord of the gray matter than in the neocortices. The topographical distribution pattern and severity of PrP(Sc) accumulation were mapped and plotted as immunohistochemical profiles of the different brain areas along the caudal-rostral axis of the brain. The distribution pattern and severity of the immunolabeled PrP(Sc) in the CNS were almost the same among the 7 cases analyzed, suggesting that the naturally occurring cases in this study were at the preclinical stage of the disease. Immunohistochemical mapping of the PrP(Sc) deposits will be used to clarify the different stages of BSE in cattle. 相似文献
103.
Katsuji UETAKE Shigeru MORITA Yoshiko KOBAYASHI Shinji HOSHIBA Toshio TANAKA 《Animal Science Journal》2003,74(1):73-78
Calves (n = 106) on four dairy farms were observed for their approachability to humans. All calves experienced similar rearing conditions: Beginning individual pen, after birth until weaning at about 2 months, where they were housed individually and fed milk and a milk replacement; Late individual pen, after weaning until grouping at about 3.5 months, where they were housed individually and fed hay, silage and concentrate feed; Beginning group pen, after grouping until 5 months, where they were housed in groups of 2–5 animals and fed hay, silage and concentrate feed; later group pen, from 5 to 7 months. The number of calves that contacted an experimenter who stood in front of their pens for 10 min was recorded on 6 separate days over 3 months. Latency to touch and time spent in activities during touching such as sucking, licking, biting and rubbing were also measured. There were no significant differences in the latency to touch and the ratio of touch to non‐touch calves between the rearing conditions and the farms. The time spent touching was significantly affected by the interaction between the rearing condition and the farm (P < 0.01). In detail, the time spent sucking (P < 0.001) and licking (P < 0.01) was different between the rearing condition × farm variables. The proportion of calves that approached and touched the experimenter tended to be higher in the farms in which a stockperson worked longer inside and outside their pens (both ρ = 0.95, P = 0.051). These results were interpreted according to the perspectives of early positive reinforcement with food and the habituation process to humans existing nearby. 相似文献
104.
Sex and age differences in meat composition of Yeso sika deer (Cervus nippon yesoensis) reared for a short period after capture in the wild 下载免费PDF全文
Maki Hayashida Kousaku Souma Kazuki Sugo Shin‐ichi Araki Fumiaki Ishizaka Masami Ueda Takamasa Kasai Takayoshi Masuko 《Animal Science Journal》2015,86(2):207-213
Yeso sika deer captured in winter around Lake Akan in Hokkaido were reared for 8–10 months at Tokyo University of Agriculture in Abashiri. Six 1‐year‐old females and males and six 2‐year‐old or older (adult) females and males were slaughtered and their carcasses were processed. The chemical composition, mineral contents and fatty acid composition of the loin were measured. No marked influence of gender or age was noted in the chemical composition of loin. In the mineral contents, significant differences were noted. The potassium and sulfur contents were lower and the sodium content was higher in adult deer meat (P < 0.05, respectively) and the potassium content was higher in male deer meat (P < 0.05). Arsenic, cadmium or lead were not detected. In the unsaturated fatty acid, a significant interaction was detected (P < 0.05), and it was high in 1‐year‐old female deer meat and low in 1‐year‐old male deer meat. Significant gender or age differences were noted only in the mineral contents in the loin of deer reared for a short period after capture. 相似文献
105.
Ahmed Elkhateeb Ahmed A. El-Beih Amira M. Gamal-Eldeen Montaser A. Alhammady Shinji Ohta Paul W. Paré Mohamed-Elamir F. Hegazy 《Marine drugs》2014,12(4):1977-1986
Chemical investigations of the Egyptian soft coral Sarcophyton ehrenbergi have led to the isolation of compounds 1–3 as well as the previously reported marine cembranoid diterpene sarcophine (4). Structures were elucidated by comprehensive NMR and HRMS experimentation. Isolated compounds were in vitro assayed for cytotoxic activity against human hepatocarcinoma (HepG2) and breast adenocarcinoma (MCF-7) cell lines. 相似文献
106.
In the field of agriculture, development of evaluation techniques for environmental changes is urgently required for the purpose of finding a balance between growth in agricultural productivity and environmental considerations. The habitat evaluation procedures (HEP) constitute one technique for habitat assessment. While HEP is widely applied to estimate both habitat quality and quantity in an environment, it appears to be necessary to develop an accurate habitat prediction model in order to evaluate environments precisely. In fact, habitat selection by fish is affected by complicated interaction between multiple environmental factors, which makes it difficult to relate physical environments to habitat preference. In the present study, we utilize artificial neural networks (ANNs), which are commonly applied to model complex systems, to predict the habitat selection of Japanese medaka (Oryzias latipes) in agricultural canals. Considering the essential vagueness of fish behavior, fuzzy membership functions are introduced into the input layer, which advances ANN to fuzzy neural network (FNN). In addition, symmetric triangular fuzzy numbers are employed to account for uncertainty in measurement errors and dispersions of physical environment. The FNN model precisely predicts the habitat preference of Japanese medaka in an agricultural canal, and the results show a good agreement between the calculated and observed habitat suitability indices (HSI). Finally, the habitat quality of two different reaches at the same point in time is compared using HEP, with a view of suitable habitat for Japanese medaka. 相似文献
107.
In order to characterize the mechanism of Al tolerance (Atlas 66) and Al sensitivity (Scout 66) in two cultivars of wheat (Triticum aestivum L.), the early responses to Al stress under acidic conditions were investigated. Marked inhibition of root elongation of Scout was observed upon treatment with 10 μM AlCl3 for less than 3 h. The inhibition of root elongation of Scout was reversed within 3 days when the treated samples were transferred to a solution without Al. However, treatment for 6 h with AlCl3 repressed root elongation almost completely and irreversibly. Root elongation of Atlas was only partially inhibited by the treatment with 10 μM AlCl3 for more than 6 h. Levels of Al in two portions of roots, namely, portions 0–5 mm and 5–10 mm from the tip, were lower in Atlas than those in Scout. In Atlas the levels of Al on a fresh weight basis in both portions were very similar, while the level of Al in the portion 0–5 mm from the tip was almost double than that in the 5–10 mm portion in Scout. A distinct increase in levels of Al in the 0–5 mm portion over that in the 5–10 mm portion of Scout was observed even after 3 h of treatment with AlCl3. Both Atlas and Scout were preloaded with K+ at pH 5.5 and transferred to distilled water at various pH values to monitor the efflux of K+. A reduction in the pH induced increases in the efflux of K+ in both cultivars, and the rate of efflux in Scout was twice that in Atlas at pH 4.2. AlCl3 at concentrations as low as 5 μM markedly repressed K+efflux at pH 4.2 and this effect was more pronounced in Scout. Ca2+ also had a repressive effect on K+ efflux, while EGTA increased K+ efflux. Vanadate increased K+ efflux, a result that suggests the involvement of a H+ pump in K+ efflux. Ca2+ failed to repress the increased efflux of K+ caused by vanadate while Al repressed the K+ efflux even in the presence of vanadate. These results suggest that a low extracellular pH may cause an increase in the cytoplasmic concentration of H+ that is followed by depolarization of the plasma membrane, which may be modified by the efflux of K+ and H+. The characteristic difference in terms of K+ efflux between Atlas and Scout at low pH may be caused by differences associated with plasma membrane potentials, as follows. The net influx of H+ at low pH, which causes depolarization of the plasma membrane, is higher in Scout than in Atlas. The difference in the net influx of H+ may be regulated in part by Ca2+, that either repress the influx of H+ or the activate of the H+ pump. Inhibition of K+ efflux by Al, which tends to depolarize the plasma membrane at low pH, may be an important factor in determining sensitivity and/or tolerance to Al. 相似文献
108.
Kousei Yamashita Minobu Kasai Yoko Yamamoto Hideaki Matsumoto 《Journal of plant nutrition》2013,36(6):657-668
The effect of nitrate (NO3) on the activities of hydrogen (H+)‐ATPase and H+‐transport in the plasma membrane vesicles isolated from barley (Hordeum vulgare L. cv. Kikaihadaka) roots was investigated. After treatment with 10 mM NO3 for longer than 24 h, both activities of H+‐ATPase and H+‐transport assayed in the presence of chloride (Cl) were stimulated less than 20%. While H+‐transport activity was approximately two times higher in NO3‐grown roots than in control roots when assayed in the presence of NO3 instead of Cl. This result suggests that NO3 is permeable in the plasma membrane vesicles isolated from NO3‐grown roots rather than that of the control, and thereby stimulate H+‐transport activity through the collapse of positive potentials established by H+‐ATPase. Furthermore, NO3 efflux from roots was markedly enhanced after 48 h of the exposure to NO3. Taken together, NO3 efflux may be mediated by the permeability to NO3 which is induced by NO3. 相似文献
109.
Nguyen Van Phi Hung Shiori Watanabe Shinji Ishikawa Norikuni Ohtake Kuni Sueyoshi Takashi Sato 《Soil Science and Plant Nutrition》2013,59(6):888-895
The quantitative analysis of the initial transport of fixed isotope 15-nitrogen (15N) in intact nodulated soybean plants (Glycine max [L.] Merr. cv. Williams) was investigated at the vegetative stage (36 days after planting, DAP) and pod-filling stage (91 DAP) by the 15N pulse-chase experiment. The nodulated roots were exposed to N2 gas labeled with a stable isotope 15N for 1 h, followed by 0, 1, 3 and 7 h of exposure with normal air. Plant roots and shoots were separated into three sections (basal, middle and distal parts) with the same length of the main stem or primary root. Approximately 80 and 92% of fixed N was distributed in the basal part of the nodulated roots at the vegetative and pod-filling stages by the end of 1 h of 15N2 exposure, respectively. In addition, about 90% of fixed 15N was retained in the nodules and 10% was exported to root and shoot after 1 h of 15N2 exposure at 91 DAP. The percentage distribution of 15N in the nodules at the pod-filling stage decreased from 90% to 7% during the 7 h of the chase period, and increased in the roots (14%), stems (54%), leaves (12%), pods (10%) and seeds (4%). The 15N distribution was negligible in the distal root segment, suggesting that N fixation activity was negligible and recycling fixed N from the shoot to the roots was very low in the initially short time of the experiment. 相似文献
110.
Abstract In this study energy-dispersive X-ray analysis was used to discover changes in the composition of phytin globoids in aleurone particles of developing rice grains. At early milky stage (the 7th to 10th day after flowering) many aleurone particles were observed as electron lucent vacuole-like particles in aleurone cells, some of which contained a small electron-dense inclusion (phytin globoid). The major mineral elements present in phytin globoids were phosphorus (P) and magnesium (Mg). Potassium (K) was also detectable but its concentration was extremely low relative to these two. Calcium (Ca) and zinc (Zn) were found as minor components. At early dough stage (the 17th to 19th day after ftowering) P, Mg and K were observed as the major mineral elements. The composition of mineral elements in phytin globoids tend to be constant in the late staae of ripening. On the other hand, minor elements, i.e. Ca and Zn, were only detectable in the early stage of ripening, suuesting that these elements accumulated in the aleurone particles only during the early stage, and in later stage their accumulation was either complete or at very low levels compared with those of K and Mg. The relative amount of Mg existing in phytin globoid remained roughly constant throughout the ripening periods, while that of K varied. Energy-dispersive X-ray analysis of phytin globoids in developing rice aleurone particles confirmed that the accumulation of P, Mg and K in rice grains was closely related to the formation of phytin globoids. This analysis suggested further that the mechanism of accumulation of P into aleurone particles was very similar to that of Mg, while that of K differed from both. The results obtained suggested that Ca and Zn might be required in the formation of phytin globoid at the early ripening stage. EDX analysis of a protein body in the starchy endosperm revealed that there was no significant element detectable in an EDX spectrum other than sulfur. This suggests that lamellar concentric structures in protein bodies are not due to phytin. 相似文献