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131.
Tatsushi Kimura Tsutomu Inamizu Kiyokazu Sekikawa Masayuki Kakehashi Kiyoshi Onari 《Journal of circadian rhythms》2009,7(1):7-6
Background
Numerous processes in the living body exhibit daily rhythmicity. In this study, we characterized a daily rhythm of blood fluidity and identified its determinants. 相似文献132.
133.
Nuttapone SANGKANJANAVANICH Tsutomu KAKUDA Yasunori SUZUKI Yukako SASAKI Shinji TAKAI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(8):1182
Rhodococcus equi is a Gram-positive facultative intracellular bacterium that causes pyogranulomatous pneumonia in foals and immunocompromised people. In the present study, signature-tagged transposon mutagenesis was applied for the negative selection of R. equi mutants that cannot survive in vivo. Twenty-five distinguishable plasmid-transposon (plasposon) vectors by polymerase chain reaction (PCR), each containing a unique oligonucleotide tag, were constructed and used to select the transposon mutants that have in vivo fitness defects using a mouse systemic infection model. Of the 4,560 transposon mutants, 102 mutants were isolated via a real-time PCR-based screening as the mutants were unable to survive in the mouse model. Finally, 50 single transposon insertion sites were determined via the self-cloning strategy. The insertion of the transposon was seen on the virulence plasmid in 15 of the 50 mutants, whereas the remaining 35 mutants had the insertion of transposon on the chromosome. The chromosomal mutants contained transposon insertions in genes involved in cellular metabolism, DNA repair and recombination, gene regulation, non-ribosomal peptide synthesis, and unknown functions. Additionally, seven of the chromosomal mutants showed a reduced ability to multiply in the macrophages in vitro. In this study, we have identified several biosynthetic pathways as fitness factors associated with the growth within macrophages and survival in mice. 相似文献
134.
Subtropical forests in the Ryukyu Islands have been degraded by silvicultural practices, and thus their structural attributes
are being shifted to other states dominated by a few tree species. This study clarified the mechanisms of the change, and
examined the effect of clear logging on the resilience of a subtropical forest. Sprouting regeneration and typhoon disturbance
were introduced into an individual-based model, SEIB-DGVM, for describing stand development and succession. The regeneration
dynamics from young secondary to old-growth stands were reproduced fairly well with the model. Sprouting recruitment produced
high stem density at the beginning of stand development, which caused a self-thinning trajectory following the −3/2 power
law. In the late development stage after 70 years, tree species diversity fluctuated because of the regenerative response
of sprouting species and the facilitatory effect of typhoon disturbance on the coexistence of subordinate species. The death
of canopy trees because of typhoon disturbances reduced the dominance of Castanopsis sieboldii, and depressed its dominance in the understory. Consequently, the understory species could establish by virtue of fallen
canopy trees, and tree species diversity increased at the stand level. Clear logging experiments in the model revealed that
species diversity deteriorated, especially in the stand dominated by sprouting species. Resilience of subtropical forests
was determined by initial species composition before clear logging. Our simulation results suggest that repeated logging drives
subtropical forests with high species diversity to a stand monopolized by C. sieboldii. 相似文献
135.
Kyoko Suzuki Tsutomu Suzuki Yukio Takahashi Mitsuhiro Okimoto Tetsuo Yamada Noriyasu Okazaki Yuichi Shimizu Masashi Fujiwara 《Journal of Wood Science》2009,55(1):60-68
The yields and properties of oil and gas fractions coproduced during carbonization of larch wood loaded with Ni 2%, Ni 2%+Ca
1%, and Ni 4% and without catalyst (None) at 700°–900°C were examined to clarify the catalytic effect in terms of conversion
into fluid fuels. The net calorific value of oil occurred mainly below 500°C and increased in the order None < Ni 2% < Ni
4% < Ni 2%+Ca 1%, while the yield decreased in this order. The same order held for the production of gases enriched with hydrogen
at 500°–700°C. Even above 800°C, markedly promoted evolution of hydrogen took place for all catalyst systems. These observations
confirmed the effectiveness of nickel-catalyzed carbonization at 900°C, particularly Ni 2%+Ca 1%, for both upgrading of oil
and gaseous fractions, although the quality of oil was not satisfactory. The catalysis of nickel with and without calcium
is discussed on the basis of the modified Broid-Shafizadeh scheme, and the scheme was altered to adapt to the high temperature
region where oil was no longer produced.
Part of this study was presented at the 14th Annual Meeting of the Japan Institute of Energy, Suita, August 2005, and at the
18th Symposium, Session D, of the Materials Research Society of Japan, Tokyo, December 2007 相似文献
136.
Mitsuhiro Aihara Syun-ichi Urayama Minh Tuong Le Yu Katoh Tomoya Higashiura Toshiyuki Fukuhara Tsutomu Arie Tohru Teraoka Ken Komatsu Hiromitsu Moriyama 《Journal of General Plant Pathology》2018,84(2):92-103
Magnaporthe oryzae chrysovirus 1 strain A (MoCV1-A) is associated with an impaired growth phenotype of its host fungus, Magnaporthe oryzae. In this report, we assayed the virulence and pathogenicity of MoCV1-A-infected and MoCV1-A-free M. oryzae on rice plants. MoCV1-A infection did not affect virulence-associated fungal traits, such as conidial germination and appressorium formation. However, after punch inoculation of leaves on rice plants, MoCV1-A-infected strain formed smaller lesions than the MoCV1-A-free strain did on all rice varieties tested, showing that MoCV1-A infection resulted in reduced virulence of host fungi in rice plants. In contrast, after spray inoculation of rice seedlings, in some cases, MoCV1-A-infected and MoCV1-A-free strains caused different lesion types (resistance to susceptible, or vice versa) on individual international differential rice varieties. However, we did not find any gain/loss of the fungal avirulence genes by PCR, suggesting that MoCV1-A infection can convert the pathogenicity of the host M. oryzae from avirulence to virulence, or from virulence to avirulence, depending on the rice variety. We also confirmed the correlation of these race conversion events and invasive hyphae growth of the fungi in a leaf sheath inoculation assay. These data suggested that MoCV1-A infection generally confers hypovirulence to the fungal host and could be a driving force to generate physiological diversity, including pathogenic races. 相似文献
137.
Tsutomu Hashizume Ryunosuke Watanabe Yuki Inaba Ken Sawai Ferenc Fülöp György Miklos Nagy 《Animal Science Journal》2017,88(10):1588-1594
The aim of the present study was to clarify the relationship between hypothalamic dopamine (DA) and salsolinol (SAL) for the secretion of prolactin (PRL) in goats. SAL or thyrotropin‐releasing hormone (TRH) was intravenously injected into female goats treated with or without the D2 DA receptor antagonist haloperidol (Hal), which crosses the blood‐brain barrier, and the PRL‐releasing response to SAL was compared with that to TRH. PRL‐releasing responses to SAL, Hal, and Hal plus SAL were also examined after a pretreatment to augment central DA using carbidopa (Carbi) and L‐dopa. The PRL‐releasing response to Hal alone was greater than that to SAL or TRH alone. The PRL‐releasing response to Hal plus SAL was similar to that of Hal alone. In contrast, the PRL‐releasing response to Hal plus TRH was greater than that to TRH or Hal alone. The treatment with Carbi plus L‐dopa inhibited SAL‐ and Hal‐induced PRL secretion. The inhibition of the PRL‐releasing response to SAL disappeared when SAL was injected with Hal. These results indicate that the mechanisms underlying the SAL‐induced PRL response differ from those of TRH, and suggest that hypothalamic DA and its synthesis is associated in part with SAL‐induced PRL secretion in goats. 相似文献
138.
Katsuyuki Ichitani Satoru Taura Takahiro Tezuka Yuuya Okiyama Tsutomu Kuboyama 《Rice》2011,4(2):29-38
Hybrid weakness phenomena in rice reportedly have two causes: those of HWC1 and HWC2 genes and those of HWA1 and HWA2 genes. No detailed study of the latter has been reported. For this study, we first produced crosses among cultivars carrying the weakness-causing allele on the HWA1 and HWA2 loci to confirm the phenotype of the hybrid weakness and the genotypes of the cultivars on the two loci, as reported earlier. We then confirmed that these cultivars belong to Indica. Subsequent linkage analysis of HWA1 and HWA2 genes conducted using DNA markers revealed that both genes are located in the 1,637-kb region, surrounded by the same DNA markers on the long arm of chromosome 11. The possibility of allelic interaction inducing hybrid weakness is discussed. 相似文献
139.
Defining the spatial arrangement and length of the cutting cycle in a logged area is crucial for reconciling potential conflicts
between timber yields and maintenance of ecosystem services in natural forests. In this study, we investigated long-term impacts
of clear-fell logging on timber production and tree species diversity in a subtropical forest on the Ryukyu Islands, using
an individual-based simulation model. We assumed six logging scenarios defined by combinations of forest type and regeneration
processes, which acted as surrogates for spatial scales of clear-fell logging. These scenarios were simulated under cutting
cycles ranging from 20 to 150 years. Short-cutting cycles resulted in dominance by the sprouting species Castanopsis sieboldii. The compositional shift was accelerated by the lack of seed dispersal from surrounding forest areas. The simulations demonstrated
that a sustainable logging regime maintaining both yield and tree species diversity requires a cutting cycle longer than 50 years.
The simulation results also suggest that the trade-off between the recovery of tree species diversity and timber production
is favored more in stands surrounded by mature forest than in isolated stands or stands surrounded by immature forest. Ecological
risk assessments based on model simulations provide an alternative to current forest management practices that rely on empirical
knowledge. 相似文献
140.
Tsuchida T Koga R Horikawa M Tsunoda T Maoka T Matsumoto S Simon JC Fukatsu T 《Science (New York, N.Y.)》2010,330(6007):1102-1104
Color variation within populations of the pea aphid influences relative susceptibility to predators and parasites. We have discovered that infection with a facultative endosymbiont of the genus Rickettsiella changes the insects' body color from red to green in natural populations. Approximately 8% of pea aphids collected in Western Europe carried the Rickettsiella infection. The infection increased amounts of blue-green polycyclic quinones, whereas it had less of an effect on yellow-red carotenoid pigments. The effect of the endosymbiont on body color is expected to influence prey-predator interactions, as well as interactions with other endosymbionts. 相似文献