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991.
992.
目的建立羊角子草中总黄酮含量的测定方法,并分析该类成分在羊角子草不同部位的分布情况。方法用超声法提取羊角子草中总黄酮;采用紫外-可见分光光度法于508 nm处测定总黄酮的含量。结果总黄酮在22.78~113.88μg.mL-1浓度范围内与吸光度有良好的线性关系(r=0.999 9),羊角子草中总黄酮的含量为:根0.28%,茎0.77%,叶1.60%,花1.06%,果实0.49%,平均回收率为98.62%,RSD为1.58%(n=9)。结论该方法简便、快速、准确,可用于羊角子草中总黄酮含量的测定。 相似文献
993.
研究了莱氏野村菌(Nomuraea rileyi)MZ060727-XW菌株5个浓度(3.5×104~3.5×108个/mL)对斜纹夜蛾2龄和3龄幼虫的致病性。在3.5×108个/mL孢子浓度下斜纹夜蛾2龄幼虫死亡率最高达88.58%,3龄幼虫死亡率最高达83.84%,2龄幼虫的LC50为(1.898±0.162)×104个/mL,3龄幼虫的LC50为(3.293±0.108)×104个/mL。在3.5×104~3.5×108个/mL浓度处理下2龄幼虫的LT50依次为(6.33±0.18)、(5.16±0.16)、(4.84±0.14)d和(4.27±0.11)d,3龄幼虫的LT50分别为(7.67±0.15)、(6.14±012)(、5.28±0.14)d和(4.69±0.17)d。 相似文献
994.
C. X. Hong M. E. Gallegly P. A. Richardson P. Kong G. W. Moorman J. D. Lea‐Cox D. S. Ross 《Plant pathology》2010,59(5):913-921
A new species of Phytophthora, previously referred to as taxon Dre II, is named Phytophthora hydropathica. It is heterothallic, but all isolates recovered to date are of the A1 compatibility type. Plerotic oospores are produced. Its sporangia are usually obpyriform and are nonpapillate and noncaducous. Isolates of P. hydropathica had nearly identical single‐strand conformation polymorphism (SSCP)‐based DNA fingerprints that are distinct from those of all existing species. Their closest relatives are P. parsiana and P. irrigata. This new species is able to grow at relatively high temperatures, with an optimum of 30°C and a maximum of 40°C. It was frequently isolated from irrigation water during warm summers. This species caused leaf necrosis and shoot blight of Rhododendron catawbiense and collar rot of Kalmia latifolia at two nurseries where irrigation reservoirs yielded P. hydropathica. Its potential impact on other horticultural crops is discussed. 相似文献
995.
蓬莱地区酿酒葡萄果实病害调查及室内抗病性测定 总被引:2,自引:0,他引:2
2009年7-8月对蓬莱地区酿酒葡萄果实病害种类和发病情况进行了系统的观测和调查,结果发现:引起该地区葡萄中后期烂果的主要病害有炭疽病、灰霉病、白腐病和酸腐病,其中,炭疽病和白腐病发病较重,其次是灰霉病,酸腐病相对发病轻, 且随着葡萄果实的日渐成熟,病害发病逐渐严重。室内抗病性测定发现,无伤葡萄果实对炭疽病、曲霉病和灰霉病具有不同程度的抗侵入特性,三种病害有伤接种后的病情指数进行Duncan新复极差法差异显著性分析,赤霞珠对三种病害表现出较强的抗性,其次是蛇龙珠。 相似文献
996.
997.
Peroxisome proliferator-activated receptor-γ (PPAR-γ) plays a pivotal role in controlling adipogenesis.We hypothesized that changes in dietary energy density might alter fat deposition in finishing pigs via modulation of the expression of PPAR-γ.To test this hypothesis,thirty female finishing pigs were fed diets containing low (LD),medium (MD) or high (HD) energy density.Blood samples were collected on day 53,and then the pigs were sacrificed to collect samples of the dorsal subcutaneous (ST),abdominal (AT) and mesenteric (MT) adipose tissue.Compared with pigs fed the MD diet,malate dehydrogenase activity was increased in the ST and MT of pigs fed the HD diet,while activity was decreased in the MT of pigs fed the LD diet (P0.05).Glucose-6-phosphate dehydrogenase activity was increased in all three fat depots of pigs fed the HD diet (P0.05) in comparison with pigs fed the MD diet.Both HD and LD diets increased the size of the adipocytes in the AT and MT (P0.05).Pigs fed the HD diet had a higher cell proliferation index in the ST compared with pigs fed the other two diets (P0.05).Compared with pigs fed the MD diet,a decreased apoptosis index was seen in the ST of pigs fed the HD diet,and in the AT of pigs fed the LD diet,as well as in the MT of both HD and LD fed pigs (P0.05).PPAR-γ positive percentage was elevated in the ST and MT of HD fed pigs compared with pigs fed the MD and LD diets,while it was decreased in the ST of LD compared with MD fed pigs (P0.05).These results suggest that dietary energy density may regulate fat deposition in finishing pigs.It is possible that feeding a high energy diet may induce fat deposition via up-regulation of PPAR-γ expression. 相似文献
998.
Patch-level based vegetation change and environmental drivers in Tarim River drainage area of West China 总被引:1,自引:0,他引:1
Weijing Kong Osbert Jianxin Sun Yaning Chen Yi Yu Ziqiang Tian 《Landscape Ecology》2010,25(9):1447-1455
Information on vegetation-related land cover change and the principle drivers is critical for environmental management and
assessment of desertification processes in arid environments. In this study, we investigated patch-level based changes in
vegetation and other major land cover types in lower Tarim River drainage area in Xinjiang, West China, and examined the impacts
of environmental factors on those changes. Patterns of land cover change were analyzed for the time sequence of 1987–1999–2004
based on satellite-derived land classification maps, and their relationships with environmental factors were determined using
Redundancy Analysis (RDA). Environmental variables used in the analysis included altitude, slope, aspect, patch shape index
(fractal dimension), patch area, distance to water body, distance to settlements, and distance to main roads. We found that
during the study period, 26% of the land experienced cover changes, much of which were the types from the natural riparian
and upland vegetation to other land covers. The natural riparian and upland vegetation patches were transformed mostly to
desert and some to farmlands, indicating expanding desertification processes of the region. A significant fraction of the
natural riparian and upland vegetation experienced a phase of alkalinity before becoming desert, suggesting that drought is
not the exclusive environmental driver of desertification in the study area. Overall, only a small proportion of the variance
in vegetation-related land cover change is explainable by environmental variables included in this study, especially during
1987–1999, indicating that patch-level based vegetation change in this region is partly attributable to environmental perturbations.
The apparent transformation from the natural riparian and upland vegetation to desert indicates an on-going process of desertification
in the region. 相似文献
999.
1000.
不同澳洲坚果品种抗旱性的综合评价 总被引:2,自引:1,他引:1
以36个澳洲坚果品种为研究对象,在持续干旱胁迫下测定其9项生理指标,并运用隶属函数法对品种的抗旱性进行综合分析,结果表明,‘云澳7号’、‘云澳24号’、‘云澳36号’、‘云澳32号’、‘云澳17’号为高度抗旱品种,‘云澳29号’、‘云澳2号’、‘云澳19号’为抗旱性弱的品种,其余品种为中度抗旱。运用灰色关联分析与主成分分析法,对36个品种的抗旱性与9项指标的相关性进行了分析,结果表明,叶片相对含水量、可溶性糖含量、可溶性蛋白含量、超氧化物歧化酶、游离脯氨酸含量可作为36个澳洲坚果品种重要的抗旱鉴定指标。 相似文献