全文获取类型
收费全文 | 327篇 |
免费 | 15篇 |
专业分类
林业 | 39篇 |
农学 | 10篇 |
基础科学 | 1篇 |
58篇 | |
综合类 | 21篇 |
农作物 | 7篇 |
水产渔业 | 29篇 |
畜牧兽医 | 162篇 |
园艺 | 4篇 |
植物保护 | 11篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 13篇 |
2014年 | 14篇 |
2013年 | 15篇 |
2012年 | 13篇 |
2011年 | 29篇 |
2010年 | 11篇 |
2009年 | 4篇 |
2008年 | 18篇 |
2007年 | 14篇 |
2006年 | 21篇 |
2005年 | 14篇 |
2004年 | 22篇 |
2003年 | 14篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有342条查询结果,搜索用时 15 毫秒
61.
Michael Rodgers Mark O’Connor Mark Gerard Healy Connie O’Driscoll Zaki-ul-Zaman Asam Mika Nieminen Russell Poole Markus Müller Liwen Xiao 《Forest Ecology and Management》2010
The aim of this study was to investigate the release of phosphorus (P) to receiving waters resulting from harvesting 34-year-old lodgepole pine trees in an upland peat catchment. The study site was within a 25.3-hectare (ha) area, and was drained by a stream that received flows from ploughed furrows, mainly, via collector drains, and discharged directly to the salmonid Shrahrevagh River, Burrishoole, Co. Mayo, Ireland. The study site was divided into two parts: the upstream part was left intact and the downstream part was harvested in early Autumn 2005 following implementation of forest guidelines. Good management practices such as proper use of brash mats and harvesting only in dry weather were implemented. Two instrumented stations were established – one just upstream (US) and the other just downstream (DS) of the clearfelled area. The measurement of P concentrations at the two stations commenced in May 2005, two months before the harvesting started. The daily mean P concentration at the DS station increased from about 6 μg L−1 of total reactive phosphorus (TRP) during pre-clearfelling to 429 μg L−1 in August 2006. By October 2009, four years after clearfelling, the P concentrations at the DS station had returned to pre-clearfelling levels. In the first three years after harvesting, up to 5.15 kg ha−1 of TRP was released from the harvested catchment to the receiving water; in the second year alone, 2.3 kg ha−1 of TRP was released. Linear regression can be used to describe the relationship between TRP load and water discharge. About 80% of the total phosphorus (TP) in the study stream was soluble and more than 70% of the P release occurred in storm events, indicating that traditional buffer strips with widths of 15–20 m might not be efficient for P immobilization. The P concentrations were affected by antecedent weather conditions and highest concentrations occurred during storm events following prolonged drought periods. The water extractable phosphorus (WEP) contents in the soil were significantly higher below windrow/brash material than in brash-free areas, and whole-tree harvesting should be studied as one of the means to decrease P export from blanket peats. 相似文献
62.
Keiichi Nomura H. Terai K. Yabe M. Maeda M. S. M. Rahman M. Yoshida 《The Journal of Horticultural Science and Biotechnology》2013,88(4):617-622
SummaryChanges in fruit weight, total soluble solids (TSS), sugar content and postharvest ethylene production during fruit development were compared on fruit of cherimoya (Annona cherimola Mill., cv. Big Sister) pollinated at different times (early, at the beginning of April, 1995 and late, at the end of May, 1994). Fruit weight increased by growth, independently of pollination times. Changes in TSS and sugar content were strongly affected by pollination time. In late pollinated fruits, both TSS and sugar content increased during the growth period, 110–160 d after pollination, while neither increased with fruit growth in early pollinated fruit. Moreover, changes in TSS and sugar content after ripening depended not only on pollination time but also on the growth period. With late pollination, fruit harvested after 140 d became edible after ripening. The TSS and total sugar contents, (the sum of fructose, glucose and sucrose contents) increased to about 20° Brix and above 16%, respectively. But early pollinated fruits were not edible after ripening, since total sugar content increased only to about 7%, even though they kept growing for 160 d on the tree. The maximum rate of ethylene production declined and the number of days to the ethylene peak from harvest is also reduced with growth in both cases. These changes were closely correlated with days after pollination (r>0.9) regardless of pollination time. Comparisons of accumulated temperature suggest that temperature at pollination time and during the resting period of growth affected fruit development. These results indicate that neither fruit weight nor number of days after pollination is a suitable index for harvesting time. 相似文献
63.
K. Makoto H. Shibata Y. S. Kim T. Satomura K. Takagi M. Nomura F. Satoh T. Koike 《Biology and Fertility of Soils》2012,48(5):569-577
Ecological function of charcoal has been mainly investigated by adding charcoal to soil, which is not fully adequate to understand in situ the role in fire-prone forest ecosystem. To determine in situ effects of charcoal on ecosystem functions, such as nutrient availability, we conducted an experimental burning in a Japanese white birch forest with dense coverage of dwarf bamboo in the understory with or without removal of charcoal. Ammonium-N in the remaining humus layer increased immediately after the burning, but decreased to the level of unburnt plots within 1?month of the burning. Removal of charcoal had no significant effect on the NH4 +-N dynamics. Although burning did not affect NO3 ?-N dynamics during the sampling period, charcoal removal led to a slight increase in NO3 ?-N. The available P increased immediately after the burning, but then fell at 1?month after burning. Charcoal inhibited the available P depletion and prolonged the high availability of P. Greater availability of P might be due to the adsorption of phosphate in charcoal pores. Exchangeable Ca and Mg increased gradually; charcoal appeared to extend the period of higher concentration of exchangeable Ca and Mg. Charcoal deriving from fire is a key factor in influencing available nutrient in the humus layer of post-fire forests. 相似文献
64.
Mika?OhtsukaEmail author Yoshino?Suzuki Tetsuya?Sakai Anil?N.?Netravali 《Fibers and Polymers》2004,5(3):225-229
The effect of UV and60Co gamma radiations on the physical and mechanical properties of nylon 6 mono-filaments with different draw ratios has been
studied. Specimens were exposed to either up to 25 Mrad of gamma or up to 168 hrs of intense UV irradiation. The results show
that nylon mono-filaments exposed to gamma rays, with much higher quantum energy than UV, undergo a larger extent of molecular
chain scission. Higher irradiation dose also results in the production of insoluble, macroscopic three-dimensional cross-linked
network structure. The amorphous regions with a lower density of cohesive energy (lower molecular orientation) show a higher
extent of cross linking reaction whereas amorphous regions with a higher density of cohesive energy (higher orientation) show
higher extent of chain scission reaction, irrespective of UV ray or gamma ray irradiation. 相似文献
65.
Shimbata T Inokuma T Sunohara A Vrinten P Saito M Takiya T Nakamura T 《Journal of agricultural and food chemistry》2011,59(9):4794-4800
Sweet wheat (SW), which lacks functional granule-bound starch synthase I (GBSSI) and starch synthase IIa (SSIIa), accumulates high levels of free sugars in immature seeds. Here, we examined the effects of the lack of these two enzymes on mature kernel composition. Whole grain flour of SW had higher levels of sugars, particularly maltose, slightly higher ash and protein content, approximately two to three times higher lipid levels, and about twice as much total dietary fiber as parental or wild-type lines. Considerably higher levels of low-molecular-weight soluble dietary fiber (LMW-SDF), largely consisting of fructan, were also detected in SW. Although there were no differences in total amino acid levels, the free amino acid content of SW was approximately 4-fold higher than that of wild type, and the levels of certain free amino acids such as proline were particularly high. Thus, we were able to clearly demonstrate that the lack of GBSSI and SSIIa caused dramatic changes in mature seed composition in SW. These compositional changes suggest that SW flour may provide health benefits when used as a food ingredient. 相似文献
66.
Nomura H Ogiso M Yamashita M Takaku H Kimura A Chikasou M Nakamura Y Fujii S Watai M Yamada H 《Journal of agricultural and food chemistry》2011,59(9):5150-5158
Uptake and elimination of aflatoxins (AFs) by rainbow trout ( Oncorhynchus mykiss ) during a long-term (21 days) dietary exposure were studied to assess contamination by AFs in aquaculture fish fed AF-containing feed. The uptake factor (UF) of aflatoxin B(1) (AFB(1)) in muscle ranged from 0.40 × 10(-3) to 1.30 × 10(-3). AFB(1) concentrations in liver were 165-342 times higher than in muscle. AFs from feed were more highly accumulated in liver than in muscle. Aflatoxicol (AFL) and aflatoxin M(1) (AFM(1)) were detected in muscle and liver and also in the rearing water. AFL concentrations were higher than AFM(1) by 2 orders of magnitude in muscle, and AFL was a major metabolite of AFB(1). The elimination rate constants (α) of AFB(1) and AFL in muscle (1.83 and 2.02 day(-1), respectively) and liver (1.38 and 2.41 day(-1), respectively) were very large. The elimination half-life (t(1/2)) of AFB(1) was 0.38 days (9.12 h) in muscle and 0.50 days (12.00 h) in liver. The elimination half-life of AFL in muscle and liver was 0.34 day (8.16 h) and 0.29 day (6.96 h), respectively. These data show that AFs are eliminated rapidly and are not biomagnified in fish. Thus, AFB(1) concentration in muscle of fish fed AFB(1)-containing feed (ca. 500 μg/kg) decreased to below the detection limit (20 ng/kg) of the most sensitive analytical method at 1.54 days (36.96 h) after the change to uncontaminated feed. 相似文献
67.
Mitsuo Nagane Kazunori Yoshimura Shu-Ichi Watanabe Masahiko Nomura 《Journal of circadian rhythms》2009,7(1):10-4
Background
Students suffering from psychosomatic symptoms, including drowsiness and feelings of melancholy, often have basic lifestyle problems. The aim of this study was to investigate whether psychosomatic complaints may be related to circadian dysfunction. 相似文献68.
Variations in parallel-to-grain static shear strength and perpendicular-to-grain tensile strength of Scots pine wood from
mature stands in Finland and Sweden were studied by means of linear mixed model analyses. Approximately 35% of the total variation
in shear strength could be described with readily available independent background variables; if the basic density was included,
approximately two-thirds of the total variation could be controlled. In tensile strength perpendicular to grain, only approximately
one-fourth of the total variation could be described with the respective background variables; the property was found to be
independent on wood density, and the reasons for the absence of strength–density relationship are discussed. 相似文献
69.
Une Y Murakami M Uemura K Fujitani H Ishibashi T Nomura Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(8):905-907
A polymerase chain reaction (PCR)-based method using a herpesvirus consensus primer was assessed for the identification of herpesviral infections in tortoises. A single band of about 230 bp was detected in PCR products from two out of twenty swabs taken from the oral cavity, three out of three paraffin-embedded tissue sections from the liver (two cases) and oral mucosa (one case), and one out of two fresh tissue samples from the oral mucosa. Nucleotide sequencing of these PCR products indicated that the herpesvirus present in these tortoises might belong to the alphaherpesvirinae. PCR using swabs and biopsy tissues was a sensitive and highly specific method for the diagnosis of herpesviral infections in tortoises. 相似文献
70.
K. Tagata S. Yokoyama T. Ginbo M. Honda T. Okimura M. Odakura M. Nomura S. Yamamoto 《Veterinary research communications》1996,20(1):21-30
A capillary reversed passive latex agglutination test (capillary RPLA) was developed which allows quantification of serum C-reactive protein (CRP) within approximately 15 min. The logarithmic regression line (calibration curve) obtained after measuring each CRP concentration three times in twofold dilutions of a standard canine serum containing 222 g/ml of CRP was y=6.394+0.030x (r=0.995). Capillary RPLA permitted quantification of CRP in the range 6.9–222 g/ml. The coefficients of variation ranged from 10.28% to 12.40%. The recovery rates (percentage recovery) of CRP by capillary RPLA were within the range 87% to 106%. On measuring the CRP concentrations in sera from 78 dogs by capillary RPLA, single radial immunodiffusion (SRID) and enzyme-linked immunosorbent assay (ELISA), close correlations were demonstrated between SRID and capillary RPLA (y=7.250+1.109x, r=0.978), between SRID and ELISA (y=3.042+1.059x, r=0.967), and between capillary RPLA and ELISA (y=1.778+0.929x, r=0.962). Capillary RPLA may be considered useful as a routine biochemical technique for measurement of serum CRP concentration in the dog.Abbreviations CRP
C-reactive protein
- ELISA
enzyme-linked immunosorbent assay
- RPLA
reversed passive latex agglutination test
- SRID
single radial immunodiffusion 相似文献