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81.
Chie Hayakawa Kazumichi Fujii Shinya Funakawa Takashi Kosaki 《Soil Science and Plant Nutrition》2013,59(5):663-673
Low molecular weight (LMW) organic compounds in soil solution are easily biodegradable and could fuel respiration by soil microorganisms. Our main aim was to study the mineralization kinetics of monosaccharides using 14C-radiolabelled glucose. Based on these data and the soil solution concentrations of monosaccharides, we evaluated the contribution of monosaccharides to basal respiration for a variety of tropical forest soils. Further, the factors controlling the mineralization kinetics of monosaccharides were examined by comparing tropical and temperate forest soils. Monosaccharides comprised on average 5.2 to 47.7% of dissolved organic carbon in soil solution. Their kinetic parameters (V max and KM ), which were described by a single Michaelis-Menten equation, varied widely from 11 to 152?nmol?g?1?h?1 and 198 to 1294?µmol?L?1 for tropical soils, and from 182 to 400?nmol?g?1?h?1 and 1277 to 3150?µmol?L?1 for temperate soils, respectively. The values of V max increased with increasing microbial biomass-C in tropical and temperate soils, while the KM values had no correlations with soil biological or physicochemical properties. The positive correlation between V max values and microbial biomass-C indicates that microbial biomass-C is an essential factor to regulate the V max values in tropical and temperate forest soils. The biodegradation kinetics of monosaccharides indicate that the microbial capacity of monosaccharide mineralization far exceeds its rate at soil solution concentration. Monosaccharides in soil solution are rapidly mineralized, and their mean residence times in this study were very short (0.4–1.9?h) in tropical forests. The rates of monosaccharide mineralization at actual soil solution concentrations made up 22–118% of basal respiration. Probably because of the rapid and continuous production and consumption of monosaccharides, monosaccharide mineralization is shown to be a dominant fraction of basal respiration in tropical forest soils, as well as in temperate and boreal forest soils. 相似文献
82.
Kaji Ryoma Yariuchi Rina Fujii Yumi Taniguchi Shiduku Uji Yuya Suzuki Go Kashihara Keita Kisaki Gan Suezawa Katsuhiko Ohtani Mamoru Kataoka Ikuo Akimitsu Kazuya Gomi Kenji 《Journal of General Plant Pathology》2021,87(6):361-365
Journal of General Plant Pathology - Kiwifruit bacterial canker, which is caused by Pseudomonas syringae pv. actinidiae biovar 3 (Psa3), is found throughout kiwifruit-growing countries. Here, we... 相似文献
83.
Yoshiyuki Yanase Masahiro Miura Yoshihisa Fujii Shogo Okumura Tsuyoshi Yoshimura 《Journal of Wood Science》2013,59(3):243-248
A gas detection apparatus equipped with a semiconductor gas sensor was employed for qualitative and quantitative measurement of hydrogen and methane emitted by termites. A gas sample of 2.5 ml was injected into the semiconductor gas sensor through the gas detection apparatus, and the maximum voltage of the sensor was converted into gas concentration. The gas samples were collected from three distinct experiments: (1) five combinations of workers and soldiers of Coptotermes formosanus with and without a wood specimen; (2) C. formosanus under six temperature conditions; and (3) four different termite species, C. formosanus, Reticulitermes speratus, Incisitermes minor, and Zootermopsis nevadensis. The hydrogen and methane concentrations increased with an increase in the number of termites. Concentrations were higher in samples with a wood specimen than without it. Both hydrogen and methane concentrations were the highest for the samples at 35 °C and were lowest at 15 and 5 °C. The concentrations were very low at 45 °C because all the termites had died in a few hours. The concentrations of hydrogen and methane were highest for Z. nevadensis, the dampwood termite, among the four species, and no methane was detected for I. minor, the drywood termite, at 28 °C and 75 % RH. 相似文献
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Taeko Shibaya Chika Kuroda Shinobu Nakayama Chiharu Minami Akiko Obara Takayoshi Fujii Sachiko Isobe 《Breeding Science》2021,71(2):201
In carrot (Daucus carota L.), the taproot colors orange, yellow and white are determined mostly by the Y, Y2, and Or loci. One of the most severe issues in carrot seed production is contamination by wild white carrot. To evaluate the contamination ratio, easily detectable DNA markers for white carrot are desired. To develop PCR-based DNA markers for the Y2 locus, we have re-sequenced two orange-colored carrot cultivars at our company (Fujii Seed, Japan), as well as six white- and one light-orange-colored carrots that contaminated our seed products. Within the candidate region previously reported for the Y2 locus, only one DNA marker, Y2_7, clearly distinguished white carrots from orange ones in the re-sequenced samples. The Y2_7 marker was further examined in 12 of the most popular hybrid orange cultivars in Japan, as well as ‘Nantes’ and ‘Chantenay Red Cored 2’. The Y2_7 marker showed that all of the orange cultivars examined had the orange allele except for ‘Beta-441’. False white was detected in the orange-colored ‘Beta-441’. The Y2_7 marker detected white root carrot contamination in an old open-pollinated Japanese cultivar, ‘Nakamura Senkou Futo’. This marker would be a useful tool in a carrot seed quality control for some cultivars. 相似文献
87.
Mirafiori lettuce big-vein virus (MLBVV) and Lettuce big-vein associated virus (LBVaV) are found in association with big-vein disease of lettuce. Discrimination between the two viruses is critical for elucidating the etiology of big-vein disease. Using specific antibodies to MLBVV and LBVaV for western blotting and exploiting differences between MLBVV and LBVaV in host reaction of cucumber and temperature dependence in lettuce, we separated the two viruses by transfering each virus from doubly infected lettuce plants to cucumber or lettuce plants. A virus-free fungal isolate was allowed to acquire the two viruses individually or together. To confirm the separation, zoospores from MLBVV-, LBVaV-, and dually infected lettuce plants were used for serial inoculations of lettuce seedlings 12 successive times. Lettuce seedlings were infected at each transfer either with MLBVV alone, LBVaV alone, or both viruses together, depending on the virus carried by the vector. Lettuce seedlings infected with MLBVV alone developed the big-vein symptoms, while those infected with LBVaV alone developed no symptoms. In field surveys, MLBVV was consistently detected in lettuce plants from big-vein-affected fields, whereas LBVaV was detected in lettuce plants not only from big-vein-affected fields but also from big-vein-free fields. LBVaV occurred widely at high rates in winter-spring lettuce-growing regions irrespective of the presence of MLBVV and, hence, of the presence of the big-vein disease. 相似文献
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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