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91.
92.
Transgenic bromoxynil (BX)-resistant spring oilseed rape (Brassica napus L.) was grown commercially in Canada only for two crop seasons – 2000 and 2001. We investigated the persistence of suspected BX-resistant oilseed rape volunteers in a 64-ha wheat field in Saskatchewan, Canada in 2007, 7 years after the BX-resistant cultivar BX Armor was grown. A small oilseed rape volunteer population, estimated at less than 100 plants, was observed in three main areas or patches in the field. These patches were located in low-lying areas that were too wet to plant or spray with herbicides in 2007. Viable seed was collected from 35 mature volunteers and F1 progeny screened with BX at 280 g ai/ha in the greenhouse. Progeny of all of the volunteers were visually rated as BX-resistant; the presence of the Oxy 235 transgene in leaf tissue of progeny of all volunteers was confirmed by PCR analysis. This study has documented the longest persistence of oilseed rape volunteers in Canada. Volunteers were not observed in 2008 or 2009, because of drought conditions in spring of both years. Results support the findings from previous studies that persistence of volunteer oilseed rape populations in western Canada is generally ephemeral or transitory in the absence of seed bank immigration. However, this study shows that oilseed rape transgenes can persist in the environment for a number of years even after all cultivars with the conferred trait are removed from the market. 相似文献
93.
转基因植物潜在的生物入侵问题 总被引:9,自引:0,他引:9
通过对转基因植物安全性和外来物种的生物入侵问题的研究发现,转基因植物作为自然界中本来不存在的外来物种,由于其自身的生态幅宽、繁殖能力强等竞争优势,可以通过花粉散布、种子扩散和杂交等途径造成外缘基因的逃逸,从而导致其对生态环境及生物多样性产生一定的影响。 相似文献
94.
利用阿克苏地区1975-2004年的逐日气象资料,分别采用Penman—Monteith公式与Penman修正公式计算了新疆农一师灌区的参照作物腾发量及其辐射项和空气动力项的逐日均值和旬日均值,比较了2种计算方法的绝对偏差和相对偏差,并对引起偏差的原因进行了分析。 相似文献
95.
转NDR1基因烟草对赤星病和晚疫病的抗性增强 总被引:4,自引:1,他引:4
NDR1(nonrace-specific disease resistance)基因在植物系统获得性抗性的信号传导途径中起着重要的作用,过量表达该基因的拟南芥对不同病原菌的抗性都有提高。利用PCR技术首次克隆了拟南芥Wassilewskija生态型的NDR1基因,与Columbia生态型相比,该基因共有7处碱基不同,引起编码氨基酸变化4处。构建了植物高效表达载体,利用农杆菌介导法转化烟草,经PCR和Southern鉴定,外源基因已整合到植物基因组中。随机挑选10个转基因株系进行抗病性分析,其中3个株系对赤星病和晚疫病的抗性明显增强。 相似文献
96.
以改性填料作为填料组成的膜生物反应器处理某印染废水,考察了系统对污染物去除效果及减缓膜污染方面的作用。结果表明,反应器对COD和NH3-N均有着较高的去除效果,当进出水COD浓度分别为436~1 722 mg/L、43~79 mg/L,进出水NH3-N浓度分别为160~245 mg/L、6.6~16.8 mg/L时,COD、NH3-N的去除率分别为88.99%~96.93%9、0.69%~95.94%。其出水水质达到《城镇污水处理厂污染物排放标准》(GB18918-2002)二级标准。抽吸时间20 min时的膜过滤阻力上升较快,而抽吸时间15 min能较好地维持膜通量,保持膜过滤性能的稳定。在膜通量为11.2 L/(m2.h)情况下,透膜压差随运行时间的递增而呈现缓慢上升的趋势,改性填料对减轻膜污染的贡献明显;ρ(MLVSS)/ρ(MLSS)比值与SOUR的变化趋势基本保持一致,该系统内生物膜含有较高的挥发性有机成分,具有较高的活性。改性填料的投加有效地减轻了膜污染,大大延长了膜清洗的工作周期。 相似文献
97.
Slocombe JO 《Veterinary parasitology》2006,136(2):127-135
Aims of this study with 43 equids naturally infected with Anoplocephala perfoliata in two dose titration trials were to document (i) the usefulness of a critical test with a 48 h treatment to necropsy period, (ii) efficacy of an oral paste of 0.5-2.0 mg praziquantel/kg body weight, and (iii) when after treatment would fecal egg counts provide best estimates of the tapeworm's prevalence in a herd. All feces passed by an equid after treatment and collected in successive 12 h batches were examined for tapeworms. At necropsy, tapeworms were identified as attached to the mucosa or unattached. Tapeworms were examined with a stereoscope and identified as normal or abnormal. Fecal samples were taken for egg counts at treatment and at 6 h intervals thereafter. In 32 of 36 treated equids, efficacy was 100% and mean efficacies for 0.5, 1.0, 1.5 and 2.0 mg praziquantel/kg body weight were 85.5, 99.7, 100 and 100%, respectively. Two equids treated with 0.5 mg praziquantel/kg body weight had low efficacies (5.4 and 38.1%) and normal tapeworms were found attached in the ventral colon and in one equid also in the dorsal colon. In seven untreated equids, tapeworms were primarily in the cecum with 21.3% detached. "Major fragments" or worms without a scolex but otherwise nearly a complete worm were 20.5% of the number of intact worms; they were not included in the efficacy analysis but should be. If the two equids with low efficacy were eliminated and if the number of all tapeworms and major fragments are combined less than 0.5% were in feces within 12 h of treatment, about 20% were in the 12-24 h period, 42% in 24-36h, 24% in 36-48 h and 13.5% in the equids at necropsy. One horse passed all its tapeworms in 24 h. This 48 h test when compared with a 24 h one with no examination of feces was more efficient in use of trial animals and reduced underestimation and overestimation of efficacy. However, a protocol similar to the 48 h test but with a 24 or 36 h post-treatment period should be investigated. The mean egg count peaked 18-24 h after treatment and samples taken at that time would provide the best estimate of prevalence. The Cornell-Wisconsin centrifugal flotation technique had a specificity of 100% and at 18 and 24 h its sensitivity was 94%. A brief discussion on critical and controlled tests for assessing efficacy of an anthelmintic for A. perfoliata is presented. 相似文献
98.
转基因生物技术是现代分子生物技术的一个分支学科,它的开发和应用是人类智慧的产物,人们在利用生物技术造福的同时,也可能带来安全问题,特别是转基因生物技术的滥用对生物多样性、生态环境及人体健康都可能构成危险或潜在的风险,即生态风险问题。各个国家和地区通过制定一系列的法律、法规对转基因生物技术及应用进行监管。我国当前没有关于转基因生物技术生态风险防范的全面而系统的法规体系,在分析和比较国内外转基因生物技术相关立法的基础上,提出相应的完善对策。 相似文献
99.
不同吸附剂对生物质气化焦油去除效果的影响 总被引:3,自引:0,他引:3
[目的]研究有效去除生物质气化焦油的方法。[方法]选用不同的吸附剂,比较吸附剂去除生物质气化焦油的去除效果。[结果]结果表明,锯末吸附法具有原料经济易得、操作方便、吸附率高等优点,有较高的实用价值和推广应用性。[结论]该研究结果为有效地去除生物质气化焦油提供理论指导。 相似文献
100.
研究了玉米秸秆的结构及组成、玉米秸秆中皮、瓤、叶各部分所占的比例及皮与瓤的化学组成,分析探讨了合理的玉米秸秆的皮、瓤、叶分离工艺,对分离后玉米秸秆皮原料的加工处理工艺进行了探索。为确定改性脲醛树脂胶玉米秸秆皮板的制板工艺,通过正交试验对比分析了4个因素(热压时间、热压温度、密度和施胶量)对碎料板性能指标的影响,确定较佳的玉米秸秆皮板生产工艺为:热压温度155℃、热压时间4 min(板厚度10mm)、施胶量12%、密度为0.7 g/m3。 相似文献