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981.
综述了中国2000~2030年瓶颈时期食物安全和农业水资源安全问题的各种预测;讨论了农业科技的对策;提出了实现中国农业现代化及贯彻国家生态环境建设规划(2000~2050)所需优先发展的农业工程科技领域。建议在这些优先领域,大力开展结合各个地区特定条件的国际合作研究和合资经营。开发、推广与实施先进适用型技术。指出这是获得未来潜在市场最高份额以及快速发展的途径。 相似文献
982.
3种淡水鱼肌肉脂质的组成及营养评价 总被引:4,自引:0,他引:4
以拉萨河拉萨裸裂尻鱼(Schizopygopsis younghusbandi)、拉萨裂腹鱼(Schizothorax waltoni)、双须叶须鱼Ptychobarbus dipogon)为材料,研究了其肌肉中脂质的组成和含量。结果显示:10种含量最丰富的脂肪酸分别是饱和脂肪酸16∶0和18∶0;单不饱和和脂肪酸16∶1n-9、18∶1n-9和18∶1n-7;n-3型多不饱和脂肪酸20∶5n-3,22∶5n-3和22∶6n-3和n-6型多不饱和脂肪酸18∶2n-6和20∶4n-6。结果表明拉萨河鱼类的脂肪酸模型跟深海鱼类相似,而且n-3型多不饱和脂肪酸的含量相对较高。 相似文献
983.
为进一步明确毛竹幼苗无土栽培的最佳条件,阐明毛竹N形态响应差异的影响因素,加快毛竹实生苗的培育.研究超纯水、砂和蛭石3种栽培介质,2 mM不同N形态(NH4+-N、NO3--N)以及3种pH值(3.8、5.8、7.8)处理对毛竹幼苗地上部的苗高、叶片数、叶绿素相对含量(SPAD)及地上部生物量的影响.结果表明:在蛭石和水培时,毛竹生长表现出明显的喜铵性,并且在pH为3.8时生长最好;而砂培时,毛竹幼苗生长对NH4+-N和NO3--N以及pH的响应差异都不明显.相关性分析结果表明,对地上部生长的影响为:栽培介质>pH值>N形态.毛竹幼苗生长及对不同N形态的响应受外界环境条件影响,在蛭石中栽培,供应NH4+-N为主、pH值为3.8的营养液,其生长最好.研究结果可为毛竹幼苗的无土栽培和繁育提供理论参考. 相似文献
984.
985.
986.
深圳市宝安区某家禽批发市场通过重新规划功能区、统一设置屠宰车间和代宰档、建立产品质量安全自检快检室、升级改造污水处理系统和清洗消毒设施以及设立全市统一的休市消毒制度和无害化处理制度等一系列升级改造措施,将单一的活禽批发市场,升级改造为集活禽批发、代宰和生鲜销售为一体的综合市场。在监管方面,首创活禽到生鲜禽市场内流向监管的"4联票据许可制",建立系统完善的市场内疫病监测机制以及官方动物检疫电子出证系统+企业(场方)家禽二维码脚锁扣标识系统的双重禽产品检疫与质量追溯体系。针对销售、屠宰时的混禽污染风险,以及市场检验人员不稳定、检疫监管仍有漏洞、活禽经营及屠宰人员疫病防控意识欠缺等问题,提出探索建立产地与家禽批发市场"点对点对接"机制、建立大数据智能化检验检疫管理平台、加强市场品检人员检疫检验培训、强化企业方的动物防疫工作第一责任人意识等建议。深圳市宝安区该家禽批发市场的升级改造作法和监管机制,对于国内其他家禽批发市场具有示范和参考意义。 相似文献
987.
Lv Jinfeng Zhou Chan Zeng Xiu Wang Yongliang Wang Jieping Wang Haiyan Gu Shanlin Wang Xiaoyan 《畜牧与饲料科学》2018,(3)
[Objective] The paper was to sequence the rbc L gene of several species belonging to Morus, and to explore the genetic relationship of Morus plants. [Method] Through DNA extraction, PCR amplification, sequencing, splicing and correction, a total of 56 rbc L gene sequences were obtained. [Result] Alignment results showed that there were 1 279 permutation sites in rbc L sequence of Morus plants; variable sites accounted for6.8% of the total sequence length, and the ratio of transition pairs to transversion pairs(R= si/sv) was 1.2. The rbc L sequence of Broussonetia papyrifera was selected as the outgroup, which was downloaded from Gen Bank. Genetic analysis results showed that M. alba, M. notabilis, M. rubra and Kuisang(the sample of this study) had distant relationship, and the other Morus plants had relatively close relationship. [Conclusion] The results lay a foundation for selection, identification and classification of Morus plants. 相似文献
988.
F. Yang Z. L. Li Q. Shan Z. L. Zeng 《Journal of veterinary pharmacology and therapeutics》2014,37(4):388-393
The pharmacokinetics of doxycycline was studied in plasma after a single dose (20 mg/kg) of intravenous or oral administration to tilapia (Oreochromis aureus × Oreochromis niloticus) reared in fresh water at 24 °C. Plasma samples were collected from six fish per sampling point. Doxycycline concentrations were determined by high‐performance liquid chromatography with a 0.005 μg/mL limit of detection, then were subjected to noncompartmental analysis. Following oral administration, the double‐peak phenomenon was observed, and the first (Cmax1) and second (Cmax2) peaks were 1.99 ± 0.43 μg/mL at 2.0 h and 2.27 ± 0.38 μg/mL at 24.0 h, respectively. After the intravenous injection, a Cmax2 (12.12 ± 1.97 μg/mL) was also observed, and initial concentration of 45.76 μg/mL, apparent elimination rate constant (λz) of 0.018 per h, apparent elimination half‐life (t1/2λz) of 39.0 h, systemic total body clearance (Cl) of 41.28 mL/h/kg, volume of distribution (Vz) of 2323.21 mL/kg, and volume of distribution at steady‐state (Vss) of 1356.69 mL/kg were determined, respectively. While after oral administration, the λz, t1/2λz, and bioavailability of doxycycline were 0.009 per h, 77.2 h, and 23.41%, respectively. It was shown that doxycycline was relatively slowly and incompletely absorbed, extensively distributed, and slowly eliminated in tilapia, in addition, doxycycline might undergo enterohepatic recycling in tilapia. 相似文献
989.
990.
Yunjie Wen Yuefeng Tang Jiong Wen Qi Wang Lingyu Bai Yanan Wang Shiming Su Cuixia Wu Jialong Lv Xibai Zeng 《Soil Use and Management》2021,37(1):151-163
The aggregate formation and stability are controlled by the dynamics of soil organic matters (SOM), but how it is related to SOM chemical composition within different‐sized aggregates is largely unknown during manure fertilization. In this study, the variations of intra‐aggregate organic carbon (OC), including intra‐particulate organic matter (iPOM) and mineral‐associated organic matter, were quantitatively and qualitatively analysed, and then, their effects on aggregate formation and stability were assessed under four treatments: control (CK), mineral fertilizer (NPK), reduced manure (30%M) and manure fertilizers (M). Manure application (M) significantly increased macroaggregate proportion, mean weight diameter (MWD), and OC contents within different‐sized aggregates compared to CK, NPK, and 30%M. The OC accumulation of macroaggregate in M was attributed to OC content increase in silt plus clay subfraction rather than iPOM with more labile organic groups; oppositely, in microaggregate it was located in the relatively stable fine iPOM. The macroaggregate formation and stability were controlled by the fine iPOM within macroaggregates, whose abundant polysaccharide‐C and aliphatic‐C after manure fertilization advanced the microbial growth except for Gram‐positive bacteria, which further promoted macroaggregate formation and stability. The free silt plus clay fraction also affected macroaggregate formation and stability, and its polysaccharide‐C derived from microorganisms or decomposing SOM was positively associated with MWD and macroaggregate proportion. Because polysaccharide‐C can be easily associated with mineral particles, further improving micro‐ or macroaggregation. We conclude that continuous manure fertilization could increase labile SOM accumulation within aggregates and then facilitate microbial growth, which collectively are responsible for aggregate formation and stabilization. 相似文献