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101.
1 HISTORICAL PROCESS ANDPRESENT SITUATION ON PRIVATEFORESTRY IN CHINABefore 1978, all the private sectors were bannedto own forest tenure in China. At that time, forestwas managed by state-run forest farms, state-runforestry industry bureaus or collectives. When thereform and opening-up policy was initiated inChina, with the implementation of HouseholdResponsibility System (HRS) in rural areas, privatesectors began to participate in forestry. In March1981, the State… 相似文献
102.
综述了植物源农药(包括植物源杀虫剂、植物源杀菌剂、植物源除草剂)的研究和开发应用现状。较详细地介绍了几种典型杀虫植物注要包括楝科植物、豆科鱼藤属植物、卫矛科植物)的杀虫机理和开发应用情况,并讨论了植物源杀虫剂今后研究的几个热点:生物技术在植物源杀虫剂研究中的应用;植物源光活化毒素的研究;杀虫植物资源的进一步调查研究。与植物源杀虫剂相比,植物源杀菌剂和除草剂的研究和应用要少得多。然而目前人们已经在植物体内发现许多具有杀菌、除草活性的物质,因此开发植物资源合成杀菌剂和除草剂具有巨大的潜力。 相似文献
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104.
Synchrony between development of five corn hybrid varieties of various seasonal growing rates (FAO numbers), seasonal flight
pattern of male cotton bollworm, Helicoverpa armigera Hb. (Lepidoptera: Noctuidae), as monitored by pheromone traps, and the subsequent appearance of newly hatched larvae on developing
cobs were studied at Mezőhegyes, South-Hungary, in 2003 and 2004. The phenological stages of corn hybrids were evaluated using
the Iowa State University Scale (R1–R5), the flight of male moths was monitored by large capacity, funnel type of pheromone traps and the appearance of freshly
hatched larvae on developing cobs were counted by visual inspection. The synchrony between the flight peak of male moths and
the peak apperance of L1 larvae on cobs was investigated by cross-correlation. In 2003 (average daily temperatures 20.7°C, average daily relative
humidity 59.9% for the period of 4–18 July) “DK 391”, “DK 443” and “Maraton” hybrid varieties already reached silking stage
(R1) by the time when pheromone traps indicated a peak, at 7 July (peak capture at 3-day intervals 755.5 males/traps). The number
of L1 larvae peaked on developing cobs of these varieties also at 7 July (7.0, 4.0 and 3.8 larvae/50 cobs, respectively). The synchrony
between the flight peak of male moths and the peak appearance of L1 larvae on cobs was proven (LAG = 0). A rather similar trend was observed in “Vilma” hybrid variety: it reached R1 stage at 7 July, and L1 larvae appeared only a few days later (11 July, 3.8 larvae/50 cobs) (LAG = −1). However, “Maxima” hybrid variety reached
R1 stage 1 week later (14 July) than the time of peak captures. Here L1 larvae peaked as late as at 18 July (0.8 larvae/50 cobs), i.e., only after the cob had reached R1 stage (LAG = −3). A reverse order of dates of R1 stage and peak capture was observed in “Maxima” in 2004 (average daily temperatures; 22.5°C, average daily relative humidities
72.6% for the period of 15 July–6 August): it reached R1 stage at 19 July, while peak trap captures were recorded at 6 August (peak capture at 3-day intervals 20.5 males/traps).
L1 larvae were found in the highest numbers on 2 August (1.5 larvae/50 cobs), practically in synchrony with peak caputres (LAG = 0).
“Káma” reached R1 stage in 16 July, and L1 larvae peaked at 2 August (1.3 larvae/50 cobs) (LAG = 0). On the rest of the corn varieties larvae were found only in too
numbers for performing statistical analysis. We conclude that in order to predict the appearance of L1 larvae, the phenological stage of the corn variety and the seasonal flight pattern of moths, as measured by large capacity
pheromone traps, should be considered in combination. If the corn variety already reached R1 stage, L1 larvae appear on cobs as early as the time of peak flight of moths. However, no young larvae appear on cobs despite of high
trap captures, until the corn reaches the R1 stage. These findings are discussed in the view of specifying optimal timing of a pesticide application. 相似文献
105.
106.
论中国的环境税--税收手段治理环境 总被引:2,自引:0,他引:2
环境税是政府通过税收手段矫正制度失灵(市场失灵和政府失灵),实现环境保护和资源保护的一个有效工具。环境税的征收从经济角度为解决我国日益严重的环境问题提供了思路,但目前我国的环境保护税费制度不适应市场经济体制。我国环境税制建设本身需要分为近期和远期规划进行实施,同时需要从宏观方面进行配套建设。 相似文献
107.
大栗鳃金龟自1985年首次在临夏太子山林区发生后,以5年为一周期于1990年、1995年定期发生。该虫以幼虫和成虫在土壤内越冬,也以幼虫和成虫对林木幼苗造成巨大为害。幼虫期采用50%辛硫磷乳剂600倍液、80%敌敌畏乳剂600倍液,防治效果达90%以上。成虫期采用黑光灯诱杀、人工捕捉,25%氧乐菊酿乳剂800倍液或“666”烟剂防治,均能收到很好的效果。 相似文献
108.
我国林业税费体制分析 总被引:1,自引:0,他引:1
随着我国农村税费改革的不断深化,作为农村税费改革一个重要组成部分的林业税费改革越来越引起各级政府和社会有关方面的关注。文章针对我国林业税费改革中的突出问题,在客观、准确地描述现行林业税费体系的基础上,用经济学的方法对林业税费进行分析,提出对我国林业税费改革的建议。 相似文献
109.
110.