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321.
Many reports have been published about designing the strength of glulam using simulation methods. In simulation methods, one of the most important problems is how to deal with correlations among strength factors, i.e., modulus of elasticity (MOE), modulus of rupture (MOR), tensile strength (σT), and compression strength (σC). For example, in the case that the MOR criteria of glulam is σ ni /f ni + σ bi /f bi ≥ 1 (where σ ni and σ bi are the axial stress and the bending stress of the i-th lamina respectively, and f ni and f bi are the axial strength and the bending strength of the i-th lamina respectively), a correlation between f ni and f bi exists. How can we account for this correlation when calculating the strength of glulam, bearing in mind that it is very difficult to measure the correlation coefficients among MOR, σT, and σC? We developed a method by which these problems could be solved, and, using random variables generated by this method, the strengths of glulam were simulated. The simulated values were almost the same as the experimental values. The results indicated the usefulness of the method. 相似文献
322.
Marian Malek Takashima Yusuke Harsonowati Wiwiek Murota Haruhiko Narisawa Kazuhiko 《European journal of plant pathology / European Foundation for Plant Pathology》2022,163(1):97-112
European Journal of Plant Pathology - Pythium root rot is one of the most destructive diseases on lisianthus in Japan. Current management strategies against Pythium root rot are insufficient in... 相似文献
323.
Suspended particulate matter (SPM) and PM2.5 in the urban and suburban atmosphere of the Kanto Plain of Japan, which includes the Tokyo metropolitan area, during the period 22–26 July 2002 were characterized. Samples of SPM and PM2.5 were collected by low-volume samplers at 6-h intervals at Suginami, Saitama, and Kisai. At all the sites, the major components of SPM and PM2.5 were organic carbon (OC), elemental carbon (EC), and sulfate. The ion balance, the size distributions of the ionic species, and the high correlation between SO4 2? and NH4 + indicated that the main chemical form of sulfate was (NH4)2SO4. The OC/EC ratios were larger in the daytime than in the nighttime. The correlation coefficients of OC, OC/EC, and SO4 2? with ozone concentrations at inland sites (Saitama, Kisai) were higher than those at the coastal site (Suginami). Bound water and hydrogen and oxygen atoms associated with OC, the amounts of which were estimated with a mass closure model, contributed substantially to the total particle mass. The chemical characteristics of the particles indicated that two mechanisms led to high concentrations of SPM and PM2.5: (i) an active photochemical process produced high concentrations of OC and sulfate, leading to a high concentration of (NH4)2SO4 in the particles and to production of secondary organic aerosols; (ii) stable meteorological conditions resulted in accumulation of primary particles, mainly emitted from vehicle exhaust, resulting in high concentrations of OC and EC. 相似文献
324.
Taku Tsuyama Natsumi Shimada Taichi Motoda Yasuyuki Matsushita Yoshio Kijidani Kazuhiko Fukushima Ichiro Kamei 《Journal of Wood Science》2017,63(6):551-559
Bamboos are among the largest woody grasses and grow very rapidly. Although lignin is a crucial factor for the utilization of bamboo biomass, the lignification mechanism of bamboo shoots is poorly understood. We studied lignification in the bamboo Sinobambusa tootsik during culm development. Elongation growth began in May and ended in late-June, when the lignin content was approximately half that in mature culms. Thioacidolysis analysis indicated that p-hydroxyphenyl units in lignin formed even at late stages of lignification. The syringyl/guaiacyl ratio varied during culm development. Various lignin precursors were detected in developing culms by liquid chromatography–mass spectrometry. The ferulic acid content decreased from May to June, indicating that ferulic acid was utilized in early stages of cell wall formation. Monolignol glucosides were detected at early stages of lignification, whereas the contents of monolignols, coniferaldehyde, sinapaldehyde, p-coumaric acid, and ferulic acid peaked at later stages of lignification. Therefore, lignin precursors may be supplied differentially during the lignification process. In August, the rate of lignification decreased, although the contents of various lignin precursors peaked, implying that the rate-limiting step in the cessation of lignification in bamboo is transport or polymerization of lignin precursors, rather than their biosynthesis. 相似文献
325.
Non-random gametoclonal variation in rice regenerants from callus subcultured for a prolonged period under high osmotic stress 总被引:1,自引:0,他引:1
Gametoclonal variations were investigated in rice plants regenerated from anther-derived callus after subculture for two different
periods (4–6 and 20 weeks) in medium with two levels (292 and 438 mM) of mannitol. A high osmotic stress by mannitol in subculture
medium contributed to the maintenance of high regeneration ability. The frequency of diploid regenerants (R0 plants) increased and that of haploids decreased from callus subcultured for the longer period in medium with the higher
concentration of mannitol. R1 regenerant lines displayed variations in all six agronomical traits studied at the frequencies of 63% and 88% after subculture
for 4–6 weeks and 20 weeks, respectively. High homozygosity was suggested in most of the R1 lines for these traits by the similar levels of variance to those in the control variety. A principal component analysis
showed a skewed distribution of variants towards dwarfness and less panicle weight in the regenerants from callus subcultured
for 20 weeks with 438 mM mannitol. Two short culmn variants were shown to be due to single or double recessive mutations.
The results suggested that prolonged subculture under high osmotic stress causes non-random selection of homozygous gametoclonal
variations in rice anther culture.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
326.
Agronomic properties (whole stalk yield, fiber length distribution, chemical composition) and whole stalk kraft pulp characteristics (total pulp yield, pulp fiber length distribution, pulp sheet strengths) were examined for kenaf (variety Zhehong 8310) at four plant populations, ranging from 135 000 to 405 000 plants/ha on arid hillside land at Anji, Zhejiang, China. For agronomic properties, the final whole stalk yield was higher as the plant population increased and as the altitude of the location on the slope decreased. Average fiber lengths of bast and core showed maxima at 225 000 plants/ha. Cellulose content increased as the plant population increased. For the kraft pulp characteristics of kenaf whole stalk, the total pulp yield was lower as the plant population increased, with the maximum difference about 1.3%. Sheet strengths and average fiber length attained maxima at around 225000–315000 plants/ha. The largest pulp strengths (breaking length, burst index, and folding endurance) were seen at a plant population of 225000 plants/ha, and the largest tear index was seen at a plant population of 315 000 plants/ha. When the agronomic properties and whole stalk kraft pulp characteristics were combined, a plant population between 225 000 and 315 000 plants/ha, which is a little higher than that of kenaf bast production for textiles, was selected as the optimum cultivated kenaf plant population for whole stalk kraft pulp and papermaking on arid hillside land in China. 相似文献
327.
Various physiological functions of dietary glucosylceramides (GlcCer) have been reported, such as preventing colon cancer
and improving skin barrier function. One potential GlcCer source used as a foodstuff is sea cucumber. In this study, our objective
was to determine the effect of dietary GlcCer prepared from sea cucumber on plasma and liver lipids in cholesterol-fed mice.
ICR mice were fed four different diets (control diet, sea cucumber GlcCer supplemented diet, high cholesterol supplemented
diet, and high cholesterol + sea cucumber GlcCer supplemented diet). Dietary GlcCer decreased total cholesterol significantly
in ICR mice. The mRNA expression of LDL receptor was increased significantly, while the expression of the gene CYP7A1, which is involved in bile acid formation, was decreased significantly compared with the control (diet without cholesterol).
These results suggest that the expression of the cholesterol homeostasis gene in liver is modulated due to the cholesterol
lowering effect of dietary GlcCer. 相似文献