全文获取类型
收费全文 | 203篇 |
免费 | 13篇 |
国内免费 | 2篇 |
专业分类
林业 | 18篇 |
农学 | 3篇 |
39篇 | |
综合类 | 8篇 |
农作物 | 7篇 |
水产渔业 | 32篇 |
畜牧兽医 | 104篇 |
植物保护 | 7篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 10篇 |
2012年 | 5篇 |
2011年 | 10篇 |
2010年 | 5篇 |
2009年 | 19篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 17篇 |
2003年 | 10篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
排序方式: 共有218条查询结果,搜索用时 15 毫秒
101.
Yu Sasada Khin Thawda Win Ryoko Nonaka Aye Thida Win Koki Toyota Takashi Motobayashi Masaaki Hosomi Chen Dingjiang Jun Lu 《Biology and Fertility of Soils》2011,47(8):949-956
We have examined the effects of different types of slurry on CH4 and N2O emissions, Zn and Cu contents of rice, and nitrate content of the drainage water. The experiment included four treatments: (1) anaerobically digested cattle slurry (ADCS), (2) ADCS filtered to remove the coarse organic matter fraction, (3) anaerobically digested pig slurry (ADPS), and (4) chemical fertilizer (CF). The application rate was 30?g?NH4?CN?m?2. Different amounts of C were incorporated with fertilization: 725?g?C?m?2 in ADCS, 352?g?m?2 in filtered ADCS, and 75?g?m?2 in ADPS. The average CH4 emissions during a growing period were 304, 359, 452, and 579?mg?m?2?day?1 in the CF, ADPS, filtered ADCS, and ADCS treatments, respectively. The CH4 emission was significantly higher in ADCS than in CF and ADPS. Negligible N2O emissions were observed during the growing period. Comparable concentrations of Zn and Cu were observed in the rice grain among the treatments. In contrast, their concentrations in the stems and leaves were significantly higher in ADPS than in CF treated rice, although the values were lower than the upper limit of feed additives. Nitrate concentrations in the drainage water were consistently low (0.5?mg?N?L?1). The present study suggested that ADPS, containing a lower amount of C than ADCS, might be an organic fertilizer in paddy field with comparable environmental impacts to chemical fertilizers (CF), but long-term field studies are needed to better understand the effects of these organic fertilizers. 相似文献
102.
103.
Noriko Hosomi Takahiro Furutani Noriyuki Takahashi Toshiro Masumoto Haruhisa Fukada 《Fisheries Science》2014,80(3):483-492
Neuropeptide Y (NPY) and cholecystokinin (CCK) play important roles in regulating appetite in vertebrates, including mammals and fish. Understanding the appetite mechanism is important in aquaculture to improve production performance. The yellowtail Seriola quinqueradiata is one of the most cultured fish in Japan, but little is known about its appetite hormones. In the present study, complementary DNA encoding for NPY was cloned in yellowtail and consists of 604 bp, in which deduced amino acid sequences show high identity to those of other teleosts. In tissue distribution, the npy and cck mRNAs were detected in all examined tissues (whole brain, telencephalon, optic tectum, hypothalamus, cerebellum, pituitary, retina, stomach, pyloric caeca, anterior intestine, liver, and kidney). In the fasting experiment, only npy mRNA expression in the hypothalamus responded to fasting, showing a significantly high value compared with that in control fish. The expression of cck mRNA in the examined tissues did not change with fasting. The npy mRNA expression in the hypothalamus might be involved in feeding regulation in yellowtail. 相似文献
104.
Atsuya Yamashita Yuusuke Fujimoto Mayumi Tamaki Andi Setiawan Tomohisa Tanaka Kaori Okuyama-Dobashi Hirotake Kasai Koichi Watashi Takaji Wakita Masaaki Toyama Masanori Baba Nicole J. de Voogd Shinya Maekawa Nobuyuki Enomoto Junichi Tanaka Kohji Moriishi 《Marine drugs》2015,13(11):6759-6773
The current treatments of chronic hepatitis B (CHB) face a limited choice of vaccine, antibody and antiviral agents. The development of additional antiviral agents is still needed for improvement of CHB therapy. In this study, we established a screening system in order to identify compounds inhibiting the core promoter activity of hepatitis B virus (HBV). We prepared 80 extracts of marine organisms from the coral reefs of Indonesia and screened them by using this system. Eventually, two extracts showed high inhibitory activity (>95%) and low cytotoxicity (66% to 77%). Solvent fractionation, column chromatography and NMR analysis revealed that 3,5-dibromo-2-(2,4-dibromophenoxy)-phenol (compound 1) and 3,4,5-tribromo-2-(2,4-dibromophenoxy)-phenol (compound 2), which are classified as polybrominated diphenyl ethers (PBDEs), were identified as anti-HBV agents in the extracts. Compounds 1 and 2 inhibited HBV core promoter activity as well as HBV production from HepG2.2.15.7 cells in a dose-dependent manner. The EC50 values of compounds 1 and 2 were 0.23 and 0.80 µM, respectively, while selectivity indexes of compound 1 and 2 were 18.2 and 12.8, respectively. These results suggest that our cell-based HBV core promoter assay system is useful to determine anti-HBV compounds, and that two PBDE compounds are expected to be candidates of lead compounds for the development of anti-HBV drugs. 相似文献
105.
106.
107.
本研究以已建立的栽培方法、收割时期预测甘蔗单产和含糖量的数学模型为基础,提出将寻求最佳收割顺序、收割期归结为最优化组合问题,并探讨了遗传算法(GA)的解题适用性,同时进行了几种基本设定的栽培方法推移、栽培方法构成项量、行列式特性的定性分析,为求最佳的甘蔗收割顺序、收割期、不同栽培方法的面积等提供解析方法.为不使栽培方法的构成比例发生变化,与通常GA算法采用交叉在不同个体问互相交替进行不同,开发了适用本研究的GA的自己交叉具体解析法.将收割第1年期作为过渡状态,第2年期为安定状态,将两期目的函数的合并作为一个适应度进行评价. 相似文献
108.
Kenichi OTAWA Masaaki SATO Takako SASAKI Hiraku SASAKI Jun NONAKA Kikuji ITO Toshio KUROKI Yutaka NAKAI 《Animal Science Journal》2004,75(3):261-269
The ecology of shiga‐toxigenic Escherichia coli (STEC) is important in the animal production environment. We investigated fecal shedding of STEC in one town in Miyagi, Japan by multiplex polymerase chain reaction (PCR) targeting shiga toxin gene 1 (stx1), gene 2 (stx2) and malB promoter gene, and analyzed the PCR products of stx1 or stx2 (54 samples) by direct sequencing. Three of 46 (6.5%) beef cattle in the University Farm of Tohoku University (Kawatabi Farm) and 11 of 70 (15.7%) calves in neighboring dairy farms carried STEC. Rate of detecting genes of stx1, stx2 and stx1+2 was 3.4% (4/116), 8.6% (10/116) and 0.9% (1/116), respectively. Serotyping indicated that STEC contaminated farms at different times or through different routes. Isolates harbored no mutation among stx1, but six (Kawatabi Farm) and 38 (neighboring farms) base substitutions among stx2, respectively. The diversity of substitutions of stx2 was observed among farms or even in a farm. Phylogenic analysis revealed that STEC detected in the area were classified into three clusters by the variety of stx2. Sequence analysis of stx2 will be one of the tools for clarifying the source of outbreaks and the route of contamination of STEC. 相似文献
109.
Photosynthetic responses to a series of 1-min lightflecks (1,000μmol m−2 s−1) superimposed on a background with different duration (1, 5, and 10 min) and intensity (25 and 50μmol m−2 s−1) of low background photosynthetic photon flux density (PPFD) were measured in the leaves ofFagus crenata grown in a gap and understory of aFagus crenata forest in the Naeba Mountains. The two background PPFD intensities most frequently occurred in understory and gap sites respectively.
The maximum net photosynthetic rate (P
Nmax) and maximum stomatal conductance (g
smax) were higher in the gap seedlings than in the understory seedlings. However, when the background PPFD was 25μmol m−2s−1, the net photosynthetic rate (P
25) and stomatal conductance (g
s25) were almost the same between the gap and understory. When the background PPFD duration was 1-min, the net photosynthetic
rate (P
N
) at the end of each lightfleck increased progressively. When the background PPFD duration was 5- and 10-min, the increase
inP
N
at the end of each lightfleck was less. This indicates that background PPFD duration is important to photosynthetic responses
to lightflecks. The higher ratios ofP
25/P
Nmax andg
s25/g
smax in the understory seedlings indicate that the understory seedlings can maintain relatively lower levels of biochemical and
stomatal limitations than the gap seedlings under low light conditions. The ratios ofP
N
/P
Nmax at the end of each lightfleck (IS) and light utilization efficiency of single lightflecks (LUE
s) that showed the influence of lightflecks on carbon gain were higher in the understory seedlings than in the gap seedlings
when the background PPFD was 25μmol m−2 s−1. This means that understory seedling are capable of utilizing fluctuating light more efficiently under low light conditions
than the gap seedlings although the net carbon gain of single lightflecks (CG
s) in the understory seedlings was not higher than that in the gap seedlings. There were no significant differences inIS andLUE
s between understory seedlings at a background PPFD of 25μmol m−2 s−1 and gap seedlings at a background PPFD of 50μmol m−2 s−1. However,CG
s in gap seedlings was higher than in understory seedlings. These results provide more evidence thatF. crenata acclimate to a natural light environment in respect to relative induction state at low background PPFD and can capture the
fluctuating light at the same efficiency in both the gap and understory seedlings under natural light environments.
This study was funded by the research project, Evaluation of Total CO2 Budget in Forest Ecosystems, coordinated by the Ministry of Agriculture, Forestry and Fisheries of Japan. 相似文献
110.
Eka Mulya Alamsyah Liu Chang Nan Masaaki Yamada Kinji Taki Hiroaki Yoshida 《Journal of Wood Science》2007,53(1):40-46
To estimate the potential bonding performance of bonded wood products from tropical fast-growing tree species, a study on
the bondability of Paraserianthes falcataria L. Nielsen, Pinus merkusii Jungh et. De. Vriese, and Acacia mangium Willd from Indonesia was conducted. Two-ply laminations were produced using polyvinyl acetate emulsion (PVAc), urea formaldehyde
(UF), resorcinol formaldehyde (RF), and water-based polymer isocyanate (API) adhesives. In order to determine the bonding
performance, the block-shear test was applied according to the Japanese Agricultural Standard for structural glued laminated
timber under normal conditions and after accelerated-aging treatments. To support this study, the wettability of each wood
species was also investigated through contact-angle measurement. The results showed that the bonding performance of low-density
P. falcataria was better than that of medium-density P. merkusii and medium-density A. mangium, while the bonding performance of medium-density P. merkusii was better than that of medium-density A. mangium. Furthermore, compared with A. mangium, the small contact angle and good wettability in P. falcataria and P. merkusii result in better adhesion and more intimate contact between the wood surfaces and adhesive. 相似文献