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111.
We assessed stem burial and adventitious root formation of two late-successional species, Abies
mariesii and A. veitchii, in central Japan. In a plot (5 × 5 m), all seedlings between 8 and 24 cm tall were excavated: six A. mariesii seedlings in soil, and six and four A. veitchii seedlings in soil and on logs, respectively. For each sampled seedling, the number of terminal bud scars (TBS) was counted
on the aboveground and belowground stems. Stem length was measured, and divided into aboveground and belowground stems. Among
the three groups (A. mariesii seedlings in soil and A. veitchii seedlings in soil or on logs), there was no significant difference in height or total root weight (sum of adventitious roots
and primary roots), but diameter at ground level and number of TBS were significantly different. Counting TBS on the aboveground
stem of seedlings in soil underestimated seedling age, whereas the estimate was much closer to the true age for seedlings
on logs. Seedlings in soil formed more adventitious roots than seedlings on logs. A large proportion of the stem was buried
in humus for seedlings in soil, while most of the stem was not buried in humus for seedlings on logs. These results suggest
that substrate affects adventitious root formation, the formation of which is important to shade tolerance. Thus, our preliminary
results suggest that consideration of adventitious root formation is necessary to understand seedling bank dynamics and estimate
seedling ages of these Abies species in spatially heterogeneous old-growth subalpine forests. 相似文献
112.
113.
Nopporn Manajit Takafumi Arimoto Osamu Baba Seiichi Takeda Aussanee Munprasit Kamolrat Phuttharaksa 《Fisheries Science》2011,77(4):447-454
The Japanese type of set-net, Otoshi-ami, was introduced to Thailand in 2003 with the aim of assessing its feasibility as
a sustainable coastal fisheries management tool for the empowerment of coastal fishers’ communities. All preparations for
constructing and installing the set-net in the coastal waters off Mae Rumpheung beach, Rayong Province, Thailand, were carried
out by local fishers, with technical advice and support from national and international institutions. The gear was modified
and developed to suit the conditions of the fishing ground and target species. Data on the catch and sales trends in Rayong
using the set-net were collected for 7 years for statistical analysis; during this period, the gear design and marketing strategies
were improved. Simulation analysis for evaluating the cost–profit bases was conducted to establish a model for set-net technology
transfer in Southeast Asia, based on differing numbers of fishers and operation days. The simulation results show the required
size of the average daily catch to cover the total cost according to the average unit price, where the economic return point
is an average catch of 128 kg, based on a unit price of 25 Baht/kg (0.83 USD/kg), with ten fishermen and a daily operation
cost of 3,200 Baht (USD 106.17). 相似文献
114.
Takuo Hishi Reiji Fujimaki Terence P. McGonigle Hiroshi Takeda 《European Journal of Soil Biology》2008,44(5-6):473
The relationships between roots and soil communities are not well understood. We used the ingrowth-core method with L-, FH-, and M-layer substrates to investigate the relationships among soil organic carbon, fine root biomass, hyphal length and the numbers of soil microarthropods. The study was carried out in a temperate forest of the arbuscular mycorrhizal conifer, Chamaecyparis obtusa. The relationships among fine roots, fungi and soil microarthropods were different among soil substrates and faunal taxa. Soil carbon contents, fine root biomass, hyphal length and soil-microarthropod numbers were the highest in the FH-substrate, and the lowest in the M-substrate. For each substrate, the total numbers of soil microarthropods did not positively correlated with soil organic carbon. A positive correlation between fine root biomass and the soil microarthropod numbers was significant only in the M-substrate, but not in the L- and FH-substrates. In M-substrates, strong positive correlations were found between fine root biomass or hyphal length and Mesostigmata or Oribatida numbers, but Collembola numbers were not corelated. Further studies of the regulation mechanism of soil food web structures should note that the soil microarthropods have different responses to C sources according to soil conditions and trophic interactions. 相似文献
115.
The objective of this study was to assess the effect of genotyped bulls with different numbers of phenotyped progenies on quantitative trait loci (QTL) detection and genomic evaluation using a simulated cattle population. Twelve generations (G1–G12) were simulated from the base generation (G0). The recent population had different effective population sizes, heritability, and number of QTL. G0–G4 were used for pedigree information. A total of 300 genotyped bulls from G5–G10 were randomly selected. Their progenies were generated in G6–G11 with different numbers of progeny per bull. Scenarios were considered according to the number of progenies and whether the genotypes were possessed by the bulls or the progenies. A genome‐wide association study and genomic evaluation were performed with a single‐step genomic best linear unbiased prediction method to calculate the power of QTL detection and the genomic estimated breeding value (GEBV). We found that genotyped bulls could be available for QTL detection depending on conditions. Additionally, using a reference population, including genotyped bulls, which had more progeny phenotypes, enabled a more accurate prediction of GEBV. However, it is desirable to have more than 4,500 individuals consisting of both genotypes and phenotypes for practical genomic evaluation. 相似文献
116.
Drainage water quality in rice paddies was strongly influenced by the puddling of soil in the paddy fields by tractors and in response to opening of drainage gates. The concentrations of contaminants in drainage water increased rapidly when the puddling process began and were maintained at high concentrations throughout the puddling period. Moreover, the high concentrations did not decrease immediately after the puddling procedures ceased. Additionally, the ratio of dissolved nitrogen and phosphorous to total nitrogen and total phosphorous increased daily during the last half of the puddling period, due to discharge of chemical fertilizers with the drainage water. Also, the loads of particulate nitrogen and phosphorus discharged during the puddling period were larger than the loads discharge during irrigation. The discharge from paddy fields during puddling also increased the total annual contaminant load. 相似文献
117.
118.
Y Saito H Sekita M Takeda M Uchiyama 《Journal of the Association of Official Analytical Chemists》1978,61(1):129-135
An analytical method was developed for determining benzo(a)pyrene in foods, suitable for routine use. The method consists of 4 cleanup steps: (1) alkali cleavage of sample, (2) preliminary silica gel column chromatography, (3) selective extraction with concentrated sulfuric acid, and (4) further silica gel column chromatography. Recoveries of benzo(a)pyrene added to 50 g (or 10 g) food at levels of 0.4 ppb (or 2 ppb) ranged from 70% for short-necked clam and mackeral to 85% for chicken meat. The sulfuric acid extraction step affords a simple method for isolating benzo(a)pyrene from various kinds of interfering substances which could not be separated by existing methods. 相似文献
119.
120.