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61.
Hirofumi Furuita Tatsuya Unuma Kazuharu Nomura Hideki Tanaka Tsuyoshi Sugita & Takeshi Yamamoto 《Aquaculture Research》2009,40(11):1270-1278
This paper describes the relationship between the egg vitamin concentrations and the egg quality in the Japanese eel Anguilla japonica . No notable relation was found between any vitamin and the fertilization rate. Hatching and survival rates of larvae, however, significantly increased with an elevated level of egg vitamin C (VC). In contrast to VC, the relation between vitamins E (VE) and A (VA) concentrations and survival rate showed a clear peak, with a reduced survival rate at both higher and lower vitamin concentrations. The ratio of VE to lipid or highly unsaturated fatty acid (HUFA) in eggs positively correlated with hatching and survival rates of larvae. High-quality (HQ) eggs were determined as eggs that produced larvae having a survival rate higher than 80% at 8 days post hatch, and low-quality (LQ) eggs were determined as eggs that did not hatch. The level of VC of HQ was significantly higher than LQ. The results of this study suggest that HQ eggs, which produce larvae having a high survival rate, must have high levels of VC and VE/HUFA ratio and contain optimum levels of VA and VE in Japanese eel. 相似文献
62.
We investigated effects of silvicultural treatments (planting and subsequent treatments) on understory structure and plant
species diversity in managed Picea glehnii plantations (21–26 years old) in northern Japan. We evaluated the importance of each treatment (machinery site preparation,
planting, weeding, and thinning) in 19 plantations, with considerable variation among treatments overall. The understory had
98 vascular plant species; the most dominant species was a dwarf bamboo Sasa senanensis, followed by tree species Abies sachalinensis and Betula ermanii. Multiple regression analyses showed that thinning negatively influenced plant species diversity. Planting density showed
a strong positive correlation with density of seedlings (height <20 cm), but few independent variables were correlated with
density of saplings (height ≥20 cm and diameter at breast height <1 cm). The negative effect of thinning and the positive
effect of planting density seem to be related to the existence or reinitiation of dense cover of Sasa senanensis. We present possible mechanisms of response to treatments to generalize the results. We then suggest ways to improve current
treatments to meet the goals of wood production and biodiversity conservation in the region. 相似文献
63.
Takeshi Yamamoto Kazuhisa Teruya Takashi Hara Hiroto Hokazono Isao Kai Hiroshi Hashimoto Hirofumi Furuita Hiroyuki Matsunari Keiichi Mushiake 《Fisheries Science》2009,75(3):697-705
We evaluated the nutrient contents of rotifers sampled from larval-rearing tanks (tank rotifers) without water exchange during
the seed production of amberjack Seriola dumerili at three facilities (Kamiura, Kagoshima, and Miyazaki) and compared them with the nutrient contents of freshly enriched rotifers.
Compared to the enriched rotifers, the lipid contents, especially neutral lipids and proportion of 22:6n-3, tended to decrease
in the tank rotifers. These trends were clearer at Miyazaki where the tank rotifers were sampled before daily supplementation
of microalgae (Nannochloropsis). Crude protein content of the tank rotifers did not decrease markedly although the proportion of lysine tended to decrease.
Vitamin C and E contents of the tank rotifers decreased significantly only at Miyazaki. Calcium content of the tank rotifers
increased at Kamiura and Miyazaki, and the increases in iron and manganese contents of the tank rotifers at Miyazaki and zinc
content at Kagoshima were pronounced. These results suggest that the nutritional value of rotifers in larval-rearing tanks
without water exchange can be maintained by appropriate supplementation of microalgae. The effect of certain minerals that
became high in tank rotifers on subsequent larval development requires further investigation. 相似文献
64.
Takashi Nagai 《Journal of Pesticide Science》2021,46(4):366
Species sensitivity distributions (SSDs) of 38 pesticides with various modes of action were analyzed as a higher-tier ecological effect assessment based on collected acute toxicity data. Then the 5% hazardous concentrations (HC5) based on each SSD were calculated as the predicted no-effect concentrations for aquatic ecosystems. The differences between HC5 and registration criteria were small (within ten-fold) for 35 of the 38 pesticides. However, there were more than ten-fold differences for a fungicide and two herbicides. These results suggest that the current effect assessment scheme could underestimate the effect of such pesticides. This could be caused by differences in sensitivity of specific properties of the mode of action. 相似文献
65.
Nguyen Thi Hue Linh Setsuko Nagai Noriko Nagasaka Seika Okane Yousuke Taoka 《Fisheries Science》2018,84(6):1051-1062
This study aimed to evaluate the effect of Lactococcus lactis K-C2 on the growth performance, microbial diversity, and release of free amino acids in the intestinal tract and the edible parts of young amberjack, Seriola dumerili. Fish were fed a diet with or without strain K-C2 (2?×?1010 cfu/g feed) for 25 days. The results indicated that the growth performance of fish in the treated group was significantly higher than those in the control group (p?<?0.05). The amount of five amino acids (aspartate, sarcosine, taurine, alanine, and arginine) in the gut content and 13 of 21 amino acids in the edible parts of fish in the treated group were significantly higher (p?<?0.05) than those in the control group. Sphingomonas, Propionibacterium, and Mycobacterium were observed in gut microflora of fish in both the control and treated groups. Staphylococcus and Kocuria were detected in one sample from the control and treated groups; Acinetobacter and Acidobacteria were found in one sample from the control group. L. lactis was only found in one sample in the treated group. In conclusion, the dietary administration of probiotic L. lactis stimulated growth, reduced feed consumption, and improved the nutritional value of cultured amberjack. 相似文献
66.
Noborio Kosuke Ito Yuki He Hailong Li Min Kojima Yuki Hara Hirofumi Mizoguchi Masaru 《Paddy and Water Environment》2018,16(1):81-87
Paddy and Water Environment - Hydraulic properties of soil play important roles in water and temperature regimes. Measuring hydraulic properties has been studied for decades in the laboratory and... 相似文献
67.
68.
Leila Basti Hajime Uchida Ryoji Matsushima Ryuichi Watanabe Toshiyuki Suzuki Toshifumi Yamatogi Satoshi Nagai 《Marine drugs》2015,13(12):7124-7137
The effects of temperature on growth and production of Lipophilic Toxins (LT) by a monoclonal culture of Dinophysis caudata was studied. The cell density of D. caudata increased significantly with increasing temperature, and was the highest under 27, 30, and 32.5 °C. Temperature affected the average specific growth rate (µ) during the exponential growth phase (EG), which increased from 15 °C to 30 °C, and then decreased at 32.5 °C. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that this strain of D. caudata produced only pectenotoxin-2 (PTX-2) whose concentration increased significantly with incubation period, except at 32.5 °C. It was significantly different between temperatures ≤18 °C, ≥21 °C, and 32.5 °C. The cellular toxin production (CTP, pg·cell−1·day−1) showed variation with growth phase and temperature, except at 32.5 °C. The average net toxin production (Rtox) was not affected by temperature. During EG, the average specific toxin production rate (µtox) increased significantly with increase in temperature, reaching a peak of 0.66 ± 0.01 day−1 at 30 °C, and then decreased. Over the entire growth span, µtox was significantly correlated to µ, and this correlation was most significant at 27 and 30 °C. During EG, µtox was affected by both temperature and growth. This study shows that temperature affects growth and toxin production of this strain of D. caudata during EG. In addition, a positive correlation was found between toxin production and growth. 相似文献
69.
Kazuhito Ichii Weile Wang Hirofumi Hashimoto Feihua Yang Petr Votava Andrew R. Michaelis Ramakrishna R. Nemani 《Agricultural and Forest Meteorology》2009,149(11):1907
Accurate determination of rooting depths in terrestrial biosphere models is important for simulating terrestrial water and carbon cycles. In this study, we developed a method for optimizing rooting depth using satellite-based evapotranspiration (ET) seasonality and an ecosystem model by minimizing the differences between satellite-based and simulated ET. We then analyzed the impacts of rooting depth optimization on the simulated ET and gross primary production (GPP) seasonality in California, USA. First, we conducted a point-based evaluation of the methods against flux observations in California and tested the sensitivities of the simulated ET seasonality to the rooting depth settings. We then extended it spatially by estimating spatial patterns of rooting depth and analyzing the sensitivities of the simulated ET and GPP seasonalities to the rooting depth settings. We found large differences in the optimized and soil survey (STATSGO)-based rooting depths over the northern forest regions. In these regions, the deep rooting depths (>3 m) estimated in the study successfully reproduced the satellite-based ET seasonality, which peaks in summer, whereas the STATSGO-based rooting depth (<1.5 m) failed to sustain a high ET in summer. The rooting depth refinement also has large effects on simulated GPP; the annual GPP in these regions is increased by 50–100% due to sufficient soil water during the summer. In the grassy and shrubby regions of central and southern California, the estimated rooting depths are similar to those of STATSGO, probably due to the shallow rooting depth in these ecosystems. Our analysis suggests that setting a rooting depth is important for terrestrial ecosystem modeling and that satellite-based data could help both to estimate the spatial variability of rooting depths and to improve water and carbon cycle modeling. 相似文献
70.
Yoshio MINAMI Seiko YAMANO Minako KAWAI Atsushi HIRAGA Hirofumi MIYATA 《Journal of Equine Science》2009,20(3):33-40
To find a new parameter indicating muscle fitness in Thoroughbred horses, we examined
time-dependent recovery of glycogen content and sarcoplasmic reticulum (SR)
Ca2+-ATPase activity of skeletal muscle after intensive treadmill running.
Two repeated 50-sec running sessions (13 m/sec) were performed on a flat treadmill
(approximately 90%VO2max). Muscle samples of the middle gluteal muscle were
taken before exercise (pre) and 1 min, 20 min, 60 min, and 24 hr after exercise. Muscle
fiber type composition was determined in the pre muscle samples by immunohistochemical
staining with monoclonal antibody to myosin heavy chain. SR Ca2+-ATPase
activity of the muscle and glycogen content of each muscle fiber type were determined with
biochemical analysis and quantitative histochemical staining, respectively. As compared to
the pre value, the glycogen content of each muscle fiber type was reduced by 15–27% at 1
min, 20 min, and 60 min after the exercise and recovered to the pre value at 24 hr after
exercise test. These results indicate that 24 hr is enough time to recover glycogen
content after short-term intensive exercise. The mean value of the SR
Ca2+-ATPase activity showed a slight decrease (not significant) immediately
after exercise, and complete recovery at 60 min after exercise. There were no significant
relationship between the changes in glycogen content of each muscle fiber type and SR
Ca2+-ATPase. Although further studies are needed, SR Ca2+-ATPase
is not a useful parameter to detect muscle fitness, at least in Thoroughbred horses. 相似文献