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排序方式: 共有202条查询结果,搜索用时 31 毫秒
101.
Nobuko Saigusa Sheng-Gong Li Hyojung Kwon Kentaro Takagi Lei-Ming Zhang Reiko Ide Masahito Ueyama Jun Asanuma Young-Jean Choi Jung Hwa Chun Shi-Jie Han Takashi Hirano Ryuichi Hirata Minseok Kang Tomomichi Kato Joon Kim Ying-Nian Li Takahisa Maeda Akira Miyata Yasuko Mizoguchi Shohei Murayama Yuichiro Nakai Takeshi Ohta Taku M. Saitoh Hui-Ming Wang Gui-Rui Yu Yi-Ping Zhang Feng-Hua Zhao 《Journal of Forest Research》2013,18(1):41-48
The datasets of net ecosystem CO2 exchange (NEE) were acquired from 21 forests, 3 grasslands, and 3 croplands in the eastern part of Asia based on the eddy covariance measurements of the international joint program, CarboEastAsia. The program was conducted by three networks in Asia, ChinaFLUX, JapanFlux, and KoFlux, to quantify, synthesize, and understand the carbon budget of the eastern part of Asia. An intercomparison was conducted for NEE estimated by three gap-filling procedures adopted by ChinaFLUX, JapanFlux, and KoFlux to test the range of uncertainty in the estimation of NEE. The overall comparison indicated good agreement among the procedures in the seasonal patterns of NEE, although a bias was observed in dormant seasons depending on the different criteria of data screening. Based on the gap-filled datasets, the magnitude and seasonality of the carbon budget were compared among various biome types, phenology, and stress conditions throughout Asia. The annual values of gross primary production and ecosystem respiration were almost proportional to the annual air temperature. Forest management, including clear-cutting, plantation, and artificial drainage, was significant and obviously affected the annual carbon uptake within the forests. Agricultural management resulted in notable seasonal patterns in the crop sites. The dataset obtained from a variety of biome types would be an essential source of knowledge for ecosystem science as well as a valuable validation dataset for modeling and remote sensing to upscale the carbon budget estimations in Asia. 相似文献
102.
Ji Hyung Kim Dennis K. Gomez Toshihiro Nakai Se Chang Park 《Veterinary microbiology》2010,140(1-2):109-115
In order to investigate methods for controlling systemic bacterial coldwater disease (CWD), bacteriophages that infect Flavobacterium psychrophilum were isolated by the enrichment method from pond water collected from Japanese ayu farms. The five phages isolated were classified as members of Myoviridae (PFpW-3, PFpC-Y), Podoviridae (PFpW-6, PFpW-7), and Siphoviridae (PFpW-8) and had highly variable patterns of infectivity for different F. psychrophilum isolates (n = 128). The stability tests of the phages in different waters, pHs and temperatures were assessed, and the results indicated that none of the phages were affected by ayu farm conditions. Among the phages, PFpW-3 had high infectivity for F. psychrophilum isolated from ayu and other fish and demonstrated sufficient survivability in the stability tests. Thus, PFpW-3 and its indicator strain N2-3 were inoculated into cytophaga broth at different doses of multiplicity of infection (MOI) and proved to be efficient for the reduction of bacterial growth. This study may be the basis for a further evaluation of phage therapy in the treatment of CWD in Japanese ayu farms. 相似文献
103.
104.
Shin’ichi Iida Takeshi Ohta Kazuho Matsumoto Taro Nakai Takashi Kuwada Alexander V. Kononov Trofim C. Maximov Michiel K. van der Molen Han Dolman Hiroki Tanaka Hironori Yabuki 《Agricultural and Forest Meteorology》2009,149(6-7):1129-1139
We measured evapotranspiration in an eastern Siberian boreal forest, in which the understory was cowberry and the overstory was larch, during the entire growing seasons of 2005 and 2006. We compared evapotranspiration from the understory vegetation above the forest floor EU with evapotranspiration from the whole ecosystem above the overstory canopy EO. The EU/EO ratio had a seasonal trend with a flat-bottomed U-shape during the growing season (4 May–30 September). High-EU/EO ratios at the beginning and end of the growing season were observed because larch, one of the two sources of EO, was a deciduous tree, while the understory was the evergreen cowberry. The mean daily EU values during the foliated period of larch (1 June–31 August) were 0.8 and 0.9 mm day?1, or 51.4 and 51.8% of EO in 2005 and 2006, respectively. The understory vegetation was one of the most important components of the hydrologic cycle in this forest. A significant amount of EU was caused by plant physiological control, due to the aerodynamic conductance, which was much larger than the surface conductance, leading to a smaller decoupling coefficient. We found that 71% of EU was caused by the vapour pressure deficit above the forest floor. 相似文献
105.
M Nakai T Nasu 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1991,53(4):677-681
Junctional complexes of the epithelia lining the rete testis, efferent ductules, connecting ductules and epididymal duct in the fowl were examined by transmission electron microscopy and by a tracer method using lanthanum nitrate. The junctional complexes were composed of tight junctions, adhering junctions and desmosomes. In the rete testis, one or two points of membrane fusion were observed at the tight junctions. In the efferent and connecting ductules and epididymal duct, the tight junctions consisted of a series of punctate membrane fusions. The adhering junctions and desmosomes showed no remarkable structural differences among these excurrent ducts. Vascularly infused lanthanum nitrate penetrated into the tight junctions of individual epithelia for variable distances, but was prevented from entering the lumen at the site of membrane fusion. These results suggest that the tight junctions can restrict the diffusion of materials via the paracellular route, and that they play an important role in maintaining a suitable fluid environment within the excurrent ducts. 相似文献
106.
107.
Susceptibility of cultured juveniles of several marine fish to the sevenband grouper nervous necrosis virus 总被引:4,自引:0,他引:4
Piscine nodaviruses (betanodaviruses) have been tentatively divided into four genotypes (SJNNV, RGNNV, TPNNV and BFNNV) and it is suggested that host specificity is different among these genotypes. In the present study, a betanodavirus [sevenband grouper nervous necrosis virus (SGNNV)] belonging to the redspotted grouper nervous necrosis virus (RGNNV) genotype, to which most betanodaviruses from warm water fish are identified, was evaluated for its pathogenicity to hatchery-reared juveniles of several marine fish species. When challenged with the virus by a bath method (10(5.1) TCID50 mL(-1)), sevenband grouper, Epinephelus septemfasciatus, Japanese flounder, Paralichthys olivaceus, and tiger puffer, Takifugu rubripes, displayed behavioural abnormalities and mortalities with distinct histopathological signs of viral nervous necrosis and heavily immunostained cells were observed in the central nervous tissues and retina. Bath-challenged rock fish, Sebastiscus marmoratus, and a hybrid of sevenband grouper and kelp grouper, E. moara, did not display any behavioural abnormality or mortality during the experimental period, although many fish showed slight signs of viral infection in nerve cells. Kelp grouper and red sea bream, Pagrus major, showed no behavioural abnormality, mortality or immunohistopathological changes after the virus challenge. These results are, in part, consistent with the natural host range of RGNNV, indicating the complexity in the host specificity of betanodaviruses. 相似文献
108.
To clarify the effects of inundation on the establishment of Salix gracilistyla trees, the relationship between total inundation duration and the distribution and size of trees was examined on a gravel
bar along the Miya River in central Japan. The density of S. gracilistyla was low at both low and high elevations on the gravel bar, but high at middle elevations. The density increased with up to
165 days of inundation and declined gradually with more than 165 days of inundation. Density had a negative effect on crown
area, whereas inundation duration had a positive effect. At lower elevations, growth limitation of S. gracilistyla is mainly caused by inundation stress, whereas at higher elevations it seems to be primarily due to drought stress, although
it depends on the total duration of inundation in a year (TDIY). Consequently, the density is highest at middle elevations
where trees do not become too large. These results suggest that inundation duration is one factor determining the density
of S. gracilistyla trees, which in turn affects the size of each tree. 相似文献
109.
Tomomi Terajima Tomoki Sakamoto Yuichiro Nakai Kenzo Kitamura 《Journal of Forest Research》1996,1(3):131-137
Sediment hield caused by hydraulic agents is believed to be one of the most important geomorphic processes in headwaters.
Observations of shallow groundwater levels and suspended sediment yield were used to develop relationships between subsurface
discharge and sediment movement in a valley head of a small forested watershed in Hokkaido, northern Japan. Drainage capacity
of the soil was closely correlated with subsurface soil movement in the valley head. An increase in subsurface discharge associated
with an increase in the drainage capacity of the soil depended heavily on the discharge of fine-grained particles originating
from the soil. Clogging created by the fine-grained particles in the soil caused a decrease in subsurface discharge associated
with the decline in the drainage capacity. In addition, neither the drainage capacity of the soil nor subsurface discharge
changed because of the sediment unavailability within the subsurface flow system. Accordingly, as shown by the changes in
the drainage capacity of the sedimentary soil, subsurface discharge and suspended sediment yield from the valley head showed
strong interactions. 相似文献
110.
Misako Urabe Kentaro Nakai Daigo Nakamura Masaharu Tanaka Toshio Nakatsugawa Kazuo Ogawa 《Fisheries Science》2009,75(1):63-70
An introduced pathogenic fish trematode, Parabucephalopsis parasiluri Wang, 1985 (Digenea: Bucephalidae), was studied to determine the seasonal fluctuation in its metacercariae abundance. The
timing of the recruitment period of the metacercariae and the relationship between yearly fluctuation in metacercarial abundance
and some environmental factors were also examined to develop an effective plan for disease control. Monthly changes in metacercarial
abundance in the caudal fin of pale chub (Zacco platypus) and of the prevalence of the first intermediate host (golden mussel Limnoperna fortunei) suggest that P. parasiluri generally has an annual life cycle. The metacercarial abundance in chub increased when the water temperature fell below 7°C
in winter, but the rapidity of the increase varied between 2007 and 2008. The fluctuations in the abundance of metacercariae
in winter from 2001 to 2008 showed that mean flow rate and mean water level in January were negatively related to the infection
level each year, and positively related to the mean water temperature. Based on these results, we propose a control plan for
parabucephalopsiosis involving discharge control; that is, more than 50 m3/s (corresponding to 150 m3/s in the Yodo River) of water should be flushed from upstream dams for a period of at least one week starting on the day
when the water temperature falls below 7°C. 相似文献