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41.
Four natural organic fertilizers, alone or in combination with the synthetic organic fertilizer isobutylidene diurea (IBDU),
were compared with IBDU alone for their effect on soil/root microbial populations associated with bermudagrass grown on a
golf course putting green in southern Florida, USA. Populations of total fungi, total bacteria, fluorescent pseudomonads,
Stenotrophomonas maltophilia, actinomycetes and heat-tolerant bacteria were monitored every 3 months during the 2-year study. On only one sampling date
and for only one bacterial population (S. maltophilia) was a significant difference in microbial populations obtained among the fertilizer treatments. However, the S. maltophilia populations associated with the natural organic fertilizer treatments were not significantly different from the synthetic
organic IBDU fertilizer treatment.
Received: 4 April 1997 相似文献
42.
连作大豆土壤病原菌的分离及其致病性的研究 总被引:5,自引:2,他引:5
在微生物3大类群中,细菌总数在整个大豆生育期内占绝对优势,重茬低于正茬,花期、结荚期尤为明显;放线菌数量总体变幅不大,花期、成熟期重茬高于正茬,而苗期则相反;真菌数量变化很大,重茬高于正茬,花期最为显著。在连作大豆根际土壤中,有益真菌减少,有害真菌增加。将真菌优势菌群中的尖镰孢菌、半裸镰孢菌和粉红粘帚菌回接大豆,均产生不同程度的致病性,导致大豆根腐病的发生,花期前后(38~50d)病症明显。3菌株毒素粗提物对大豆毒害性试验结果表明:大豆发芽率显著降低,植株生长受阻。 相似文献
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The exotic earthworm invasion in hardwood forests of the northern United States is associated with many ecosystem-level changes. However, less is known about the effects of the invasion on the composition of the soil microbial community through which ecosystem-level changes are mediated. Further, earthworm effects on soil microbial community composition have not been well studied in the field. To evaluate changes in bacterial and fungal abundance associated with the earthworm invasion we quantified bacterial and fungal biomass by microscopic counts in paired earthworm-invaded (earthworm) and earthworm-free (reference) plots in five forest stands in central New York (USA). Earthworms significantly increased the ratio of bacteria to fungi on an area basis (per m2), by more than two times in mid-summer and early autumn. While this effect was associated primarily with the lack of the fungal-dominated organic horizon in earthworm plots, a higher ratio of bacteria to fungi in the surface 5 cm mineral soil also contributed as it developed between spring and mid-summer. Earthworm reduction of fungal biomass was confirmed by substantially lower growth of fungal hyphae into mesh sand bags in earthworm compared to reference plots. Burrowing activity by the earthworm Lumbricus terrestris increased the ratio of bacteria to fungi over the short-term within earthworm plots, introducing small-scale spatial heterogeneity associated with burrows. Our study suggests that the exotic earthworm invasion in these northern hardwood forests markedly increased the ratio of bacteria to fungi by eliminating the fungal-rich organic horizon, and was associated localized increases in bacterial vs. fungal abundance in mineral soil, setting the stage for future research into linkages between the earthworm invasion, bacterial and fungal abundance, and ecosystem processes. 相似文献
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46.
嗜热真菌对蘑菇促生机制的研究 总被引:2,自引:0,他引:2
嗜热真菌是蘑菇堆肥二次发酵后培养阶段的主要微生物类群。它们在堆肥中的数量及活性与蘑菇的产量有很大的相关性。本文综述了近年来,国外以嗜热色串孢(Scytalidiumthermophilum)为典型种,研究其对蘑菇菌丝促生作用的生物机制的主要成果,国外主要研究了嗜热色串孢在堆肥中的分布、数量,生长动力学特性以及呼吸机制等,同时发现嗜热色串孢的呼吸作用形成适宜的CO2浓度可使得蘑菇菌丝尽早占料,获取生态优势,本文还介绍了国内有关嗜热真菌的研究及应用。 相似文献
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48.
高效脂肪酶产生真菌的筛选、鉴定及产酶条件优化 总被引:2,自引:0,他引:2
研究旨在筛选高产脂肪酶活性的菌株,并鉴定其菌属及确定其最佳产酶条件。采集富含油脂的土壤,通过溴甲酚紫平板法进行菌株分离筛选,并采用橄榄油乳化法测定脂肪酶活力。利用真菌ITS序列通用引物进行PCR扩增,将测序结果Blast比对,并建系统发育树。采用正交试验设计优化产酶条件。通过筛选得到1株产脂肪酶的真菌菌株GW-1,经鉴定为黑曲霉Aspergillus niger。经单因素试验和正交试验得到该菌的最佳产酶条件为:葡萄糖0.5%、黄豆粉2.0%、橄榄油1.0%、MgSO4.7H2O 0.1%、pH值9.0、接种量8%、装液量50 ml/250 ml、发酵4 d。在此发酵条件下,其产酶活力可达39.82 U/(ml.min)。试验结果显示,访菌株在产脂肪酶能力上具有显著优越性,且菌株GW-1产酶活力较优化前高出19.96 U/(ml.min),提高了100.50%。 相似文献
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