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101.
Tea polysaccharide conjugate is one of the main bioactive constituents of tea (Camellia sinensis L.). The chemical composition and preliminary toxicological evaluation of a tea polysaccharide conjugate was investigated to determine the possibility of using it for human consumption. Chemical analysis of tea polysaccharide conjugate showed that the tea polysaccharide conjugate was a nonstarch protein bounded acidic polysaccharide. The protein, neutral sugar, and uronic acid content of the tea polysaccharide conjugate was 3.5%, 44.2%, and 43.1%, respectively. The contents of iron, magnesium, zinc, and selenium in the tea and its polysaccharide conjugate were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES). Results showed that the contents of four elements in tea polysaccharide conjugate were much higher than that of tea power. Especially, the content of iron in tea polysaccharide conjugate was increased 5.9 times. The tea polysaccharide conjugate, when fed to mice, was found to have no toxicity to the liver, kidney, heart, thymus, or spleen of the mice and none of the mice died throughout the period of the experiment. There was no significant difference between the thymus index, spleen index, and liver index of the mice from the test and control groups (P>0.05). On the basis of the study, the tea polysaccharide conjugate may be classified either as a very low toxicity substance, that is, GHS Category 5 (globally harmonized system), or as unclassified when orally administrated to mice. It might be a candidate of dietary supplements besides the bioactivities as a polysaccharide. 相似文献
102.
Wenchuan Qu R. J. Morrison R. J. West Chenwei Su 《Water, air, and soil pollution》2007,186(1-4):15-28
In this study, benthic flux measurements of inorganic nitrogen (i.e., $ {\text{NH}}^{ + }_{4} $ , $ {\text{NO}}^{ - }_{2} $ ?+? $ {\text{NO}}^{ - }_{3} $ ) were made using a batch incubation system at different stations (i.e., shallow sandy macrophyte and unvegetated beds, and deep central mud) over four seasons in Lake Illawarra, NSW, Australia, to study the influence of different primary producers (i.e., seagrasses, microphytobenthos (MPB) and macroalgae) and/or different sediment types (i.e., sand or mud) on the benthic fluxes. In general, nutrient fluxes displayed typical diel variations, with lower flux out of sediments (release) or enhanced uptake by the sediment in the light, due to the photosynthetic activities of the plant-MPB-sediment community in Lake Illawarra during photosynthetic periods. A distinct seasonal pattern of inorganic-N fluxes was also observed (e.g., the marked difference between summers 2002 and 2003). This may be explained by the seasonal variations in the biomass and activity (growing or decay phases) of MPB, seagrass and macroalgae, which may influence their nutrient assimilation and alter the chemical conditions of surface sediments that influence the benthic geochemical processes and thus benthic nutrient fluxes. On an annual basis, unvegetated sediments displayed net DIN effluxes, while seagrass beds showed a net DIN uptake, and the highest DIN uptakes coincided with the largest standing crop of seagrass and/or macroalgae and the highest levels of benthic community production. This may be due to the enhanced denitrification and/or assimilation activity by rooted plants and macroalgae, and the effect is most efficient during periods of net growth (e.g., in Spring 2002). 相似文献
103.
抚育间伐对小兴安岭天然针阔混交林碳储量的影响 总被引:1,自引:0,他引:1
在小兴安岭地区带岭林业实验局东方红林场天然林试验区,设置6块样地,对天然针阔混交次生林进行不同强度(10%、15%、20%、25%、30%、35%)的抚育间伐;采用平均标准木法取样、实验室重铬酸钾法测定林木碳质量分数,分析不同间伐强度对乔木层地上部分生物量及碳储量的影响。结果表明:随着间伐强度的增加,乔木层地上部分生物量、碳储量整体呈先增加再减小趋势,但间伐8 a内各间伐生物量、碳储量均显著少于对照。伐后1~4 a,间伐强度20%,乔木层碳储量增长率、增长量均高于对照;间伐后1~4 a内,间伐强度20%,乔木层碳储量的恢复能力最强。间伐后5~8 a,高度间伐(间伐强度30%、35%)碳储量恢复能力最弱;间伐8 a后,各间伐强度(10%、15%、20%、25%、30%、35%)的碳储量,分别为74.93±3.42、86.96±7.31、99.24±2.43、93.64±6.68、85.23±2.11、79.54±3.38 t/hm2,林木各器官碳储量差异显著,从大到小依次为树干、树枝、树叶;间伐8 a后,各间伐树干碳储量所占比例比对照所占比例增加-0.04%~12.27%,在间伐强度为20%时树干碳储量比例最高,说明间伐强度20%有利于小兴安岭天然针阔混交林树干碳储量的累积及单株林木质量的提高。总体看,短期间伐(4 a内)利于20%间伐乔木层碳储量的迅速积累,8 a内各间伐仍处于乔木层地上部分碳储量低于对照的恢复期。 相似文献
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109.
Kathleen G. Haynes Xinshun Qu Barbara J. Christ 《American Journal of Potato Research》2014,91(3):254-259
Foliar late blight, caused by Phytophthora infestans, is an important disease problem worldwide. Foliar resistance to late blight was found in a hybrid population of the cultivated diploid species Solanum phureja-S. stenotomum (phu-stn). The objective of this study was to determine if resistance to late blight could be improved by recurrent maternal half-sib selection in the phu-stn population. Four clones from each of 72 maternal half-sib families plus the check cultivar ‘Atlantic’ were evaluated for late blight resistance in replicated field trials in Pennsylvania. The most late blight resistant clone from each of the 72 families was randomly intermated to advance the population. The cycle 1, 2, and 3 populations were evaluated in 1996–1997, 2003–2004, and 2009–2010, respectively. Percent infected foliage was recorded several times towards the end of the growing season and used to compute area under the disease progress curve (AUDPC). Mean AUDPC was 652 (cycle 1), 556 (cycle 2), and 276 (cycle 3), whereas the mean AUDPC of ‘Atlantic’ ranged from 775 to 863 each cycle. Narrow-sense heritability for resistance was estimated as 0.78, 0.77, and 0.80 in cycles 1, 2, and 3, respectively. Recurrent maternal half-sib selection continues to improve the levels of resistance to late blight in this diploid population with no adverse effect on the amount of additive genetic variance. Additional improvements for late blight resistance are likely to occur if this approach is continued. 相似文献
110.
Qu Xiaojian Zhang Deshi Zhang Xiangyu Wang SiWen Wang Changyou Wang Yanzhen Wang Yajuan Chen Chunhuan Zhang Hong Ji Wanquan 《Genetic Resources and Crop Evolution》2022,69(2):687-698
Genetic Resources and Crop Evolution - Psathyrostachys huashanica Keng f. ex P.C.Kuo (2n?=?2x?=?14, NsNs) harbor numerous useful genes and exhibit application prospects as a... 相似文献