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41.
ABSTRACT: The age distribution of the sea urchin Strongylocentrotus nudus in relation to algal zonation was studied in a sublittoral rocky area on Oshika Peninsula, northern Japan, from June 1995 through to August 1996. The algal zonation observed there extends from a shallow area of cobbles to deeper areas dominated successively by Sargassum yezoense , Eisenia bicyclis and, finally, crustose coralline red algae. One-year-old sea urchins occurred only on the cobbles and crustose corallines in contrast to the presence of 2-year-old individuals from all areas and the restricted distribution of individuals aged 3 years and over to Eisenia and crustose corallines. Calculated mean body sizes in the Eisenia area became larger after the age of 2 years compared with those in the area of crustose corallines. Spawning was ascertained histologically in both the Eisenia and crustose coralline areas, although gonad indices were higher in the former area than in the latter throughout the year. Gut contents were dominated by E. bicyclis in the Eisenia area, and by crustose coralline red algae and small algae in the crustose coralline area. Thus, the sea urchin may settle most abundantly on crustose corallines and lives there for 1–2 years. Thereafter, they expand their habitat toward the Eisenia area, where there is richer sources of food for attaining a higher growth rate and to generate heavier gonads. 相似文献
42.
Hill RC Lewis DD Scott KC Omori M Jackson M Sundstrom DA Jones GL Speakman JR Doyle CA Butterwick RF 《American journal of veterinary research》2001,62(3):440-447
OBJECTIVE: To determine effects of increased dietary protein and decreased dietary carbohydrate on hematologic variables, body composition, and racing performance in Greyhounds. ANIMALS: 8 adult Greyhounds. PROCEDURE: Dogs were fed a high-protein (HP; 37% metabolizable-energy [ME] protein, 33% ME fat, 30% ME carbohydrate) or moderate-protein (MP; 24% ME protein, 33% ME fat, 43% ME carbohydrate) extruded diet for 11 weeks. Dogs subsequently were fed the other diet for 11 weeks (crossover design). Dogs raced a distance of 500 m twice weekly. Rectal temperature, hematologic variables before and after racing, plasma volume, total body water, body weight, average weekly food intake, and race times were measured at the end of each diet period. RESULTS: When dogs were fed the MP diet, compared with the HP diet, values (mean +/- SD) differed significantly for race time (32.43 +/- 0.48 vs 32.61 +/- 0.50 seconds), body weight (32.8 +/- 2.5 vs 32.2 +/- 2.9 kg), Hct before (56 +/- 4 vs 54 +/- 6%) and after (67 +/- 3 vs 64 +/- 8%) racing, and glucose (131 +/- 16 vs 151 +/- 27 mg/dl) and triglyceride (128 +/- 17 vs 104 +/- 28 mg/dl) concentrations after racing. CONCLUSIONS AND CLINICAL RELEVANCE: Greyhounds were 0.18 seconds slower (equivalent to 0.08 m/s or 2.6 m) over a distance of 500 m when fed a diet with increased protein and decreased carbohydrate. Improved performance attributed to feeding meat to racing Greyhounds apparently is not attributable to increased dietary protein and decreased dietary carbohydrate. 相似文献
43.
44.
The wild tuber-bearing Solanumspecies represent a genetic pool of enormous diversity, embracing high variability for many agronomic traits. S. kurtzianum (ktz), S. chacoense(chc) and S. ruiz-lealii (rzl) are wild diploid self-incompatible relatives of the common potato, Solanum tuberosumssp. tuberosum, with resistance to adverse biotic and abiotic factors. Pollen-pistil/style compatibility relations and seed set in intra-
and interspecific crosses among ktz, chc and rzl were investigated. Pre- and post-zygotic hybridization barriers were detected
in the three species, with variable incidence because the percentage of genotypic combinations that produced seeds was15–30%
and 7–28% in intra and interspecific crosses, respectively. In pollen-pistil/style incompatible combinations, either pollen
grains did not germinate or pollen tube growth was arrested at different sites of the style, but mainly in its upper third.
Unilateral incompatibility was detected in both intra-and interspecific crosses, as well as bilateral incompatibility in certain
combinations. The incompatibility relations observed could be explained by a genetic model with dominant genes in pistils
that interact with corresponding dominant genes in pollen, that are independent of the S-locus. The complex arrangement of
compatibility relationships found could not be directly related to taxonomic hypothesis or geographic distribution. These
results suggest that divergence between the three species has occurred recently, and that internal barriers of reproductive
isolation have not been an important factor in their evolution.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
45.
Historical Profiles of Trace Element Concentrations in Mangrove Sediments from the Ba Lat Estuary,Red River,Vietnam 总被引:1,自引:0,他引:1
Nguyen Tai Tue Tran Dang Quy Atsuko Amano Hideki Hamaoka Shinsuke Tanabe Mai Trong Nhuan Koji Omori 《Water, air, and soil pollution》2012,223(3):1315-1330
Historical profiles of trace element concentrations were reconstructed from two mangrove sediment cores collected within the
Ba Lat Estuary (BLE), Red River, Vietnam. Chronologies of sediment cores were determined by the 210Pb method, which showed that each respective sediment core from the south and north entrances of BLE provided a record of
sediment accumulation spanning approximately 100 and 60 years. The profiles of Pb, Zn, Cu, Cr, V, Co, Sb, and Sn concentrations
markedly increased from the years of the 1920s–1950s, and leveled out from 1950s–1980s, and then gradually decreased from
1980s to present. The profiles of Cd and Ag concentrations increased from 1920s–1940s, and then decreased from 1940s to present.
The profile of Mo concentrations progressively increased from 1920s–1980s, then decreased to present. The Mn concentrations
failed to show a clear trend in both sediment cores. Results from contamination factors, Pearson’s correlation, and hierarchical
cluster analysis suggest that the trace elements were likely attributed to discharge of untreated effluents from industry,
domestic sewage, as well as non-point sources. Pollution Load Index (PLI) revealed levels higher than other mangrove sediment
studies, and the long-term variations in PLI matched significant socioeconomic shifts and population growth in Vietnam. Geoaccumulation
Index showed that mangrove sediments were moderately polluted by Pb and Ag, and from unpolluted to moderately polluted by
Zn, Cu, and Sb. The concentrations of Pb, Zn, Cu, Cr, and Cd exceeded the threshold effect levels and effect range low concentrations
of sediment quality guidelines, implying that the sediments may be occasionally associated with adverse biological effects
to benthic organisms. 相似文献