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61.
利用人工诱变和体细胞再生技术,选育出可在30℃下生长的坛紫菜耐高温品(Q-1),实验结果表明:(1)在高温(28℃和30℃)下培养15d,Q-1品系的壳孢子成活率分别为76.8%和60.1%,分裂率分别为100%和83%;而对照组野生型(WT)品系的壳孢子成活率分别为15.9%和6.7%,分裂率分别为90.4%和63.8%。Q-1品系的壳孢子成活率和分裂率均远高于WT品系。(2)在常温(24℃)下培养35d的Q-1和WT品系壳孢子苗,在24℃、28℃和30℃组中再分别培养25d,Q-1品系的苗平均体长分别增加了19.4、10.8和2.8倍,而WT品系的苗平均体长分别只增加了7.3、1.7和0.9倍;Q-1品系的苗平均体长分别为WT品系的2.5、5.8和1.9倍。另外,在28℃和30℃中培养15d的WT品系幼苗发生了大面积腐烂;而Q-1品系幼苗没有出现任何烂苗迹象,表现出较好的生长。Q-1品系在海区中试中也表现出很好的耐高温特性。2008年秋季,坛紫菜采苗后遇到了长时间的高温天气,当地传统养殖的坛紫菜野生种发生了大规模腐烂与脱苗,产量大幅度减少;而Q-1品系的苗仍然维持良好的生长势头,没有出现烂苗,取得了高产。由此证实,Q-1品系是既能较快生长又耐高温的品系,有很大的生产应用价值。 相似文献
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There are few studies on flow fields generated by aerators in fish larvae rearing tanks. The flow varies with aeration rates and tank proportions resulting in different larvae survival rates. The effects of aeration rate and aspect ratio AR (the ratio of liquid depth to tank radius) on overall flow patterns were investigated experimentally using flow visualization techniques. Two distinct types of flow patterns, a single-pair vortex system and a two-pair vortex system, were observed as the value of tank aspect ratio varied from about 1.0 to 2.0. In addition, corner vortex structures were observed in both the region between the free surface and the upper sidewall, and between the bottom wall and the lower sidewall of the tank. On the sidewall, reattachment and separation points were found, which were closely related with these vortex structures. 相似文献
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从"用户为中心"的服务理念、"面向用户问题"的服务模式、服务方式趋向个性化、服务内容知识化、服务人员角色以及用户信息行为的变化等几方面对网络环境下信息服务工作内涵的转变进行了阐述,为图书馆转变观念,努力满足用户需求,进一步开拓和创新信息服务工作提供借鉴和指导。 相似文献
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大棚草莓斜纹夜蛾的空间分布型 总被引:1,自引:0,他引:1
斜纹夜蛾Spodoptera litura(Fabricius)是大棚草莓生长初期的重要害虫。为明确斜纹夜蛾在草莓上的时空动态,连片调查了草莓上低龄幼虫数、中高龄幼虫数、受害叶片数以及叶片受害率,利用聚集度指标法、Taylor幂法则和IwaoM-m的回归法进行分析。结果表明低龄幼虫呈明显的聚集分布,中高龄幼虫则呈随机分布或均匀分布,受害叶片和受害率呈明显的聚集分布;通过聚集均数(λ)判断低龄幼虫高密度时λ>2,聚集由于成虫产卵块、初孵幼虫成聚集危害引起;低龄幼虫低密度时λ<2,聚集由植株间距等影响初孵幼虫的扩散因子引起;中高龄幼虫呈随机分布的田块的λ<2。* 相似文献
67.
Organophosphorus pesticides (OPs) are of environmental significance due to their high toxicity to animals. Binding to plasma proteins may effective influence the toxicological properties of xenobiotics. In an attempt to evaluate the affinity of phenthoate (PTA) to bovine serum albumin (BSA) and inhibitory ability of bound PTA to acetylcholinesterase (AChE), we investigated the interactions between phenthoate (PTA) and bovine serum albumin (BSA) using tryptophan fluorescence quenching and subsequent inhibition on AChE activity by PTA. The results showed that PTA caused the fluorescence quenching of BSA because of the formation of a PTA-BSA complex. Quenching constants (Ksv), determined using the Sterns-Volmer equation to provide a measure of the binding affinity between PTA and BSA at 303, 306, 310 and 313 K were (3.4295 ± 0.0763) × 10−4, (3.2446 ± 0.0635) × 10−4, (3.0434 ± 0.0856) × 10−4 and (2.8262 ± 0.0569) × 10−4 M−1, respectively. The thermodynamic parameters, ΔH and ΔS were −25.04 kJ mol−1 and 168.94 J mol−1 K−1, respectively, which indicated that the electrostatic interactions played a major role in PTA-BSA association. The presence of BSA consistently reduced the inhibitory ability of PTA on AChE, with the relative activity being increased from 46.98 to 61.71% for the concentration range of BSA between 0 and 4.0 g L−1. 相似文献
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The timing and magnitude of rainfall events in arid and semiarid regions are expected to change dramatically in future decades, which will likely greatly affect regional carbon cycles. To understand how increases in rainfall affect the diurnal patterns and temperature sensitivities (Q10) of soil respiration (RS) and its key components (i.e. heterotrophic respiration (RH) and autotrophic respiration (RA)), we conducted a manipulative field experiment in a desert ecosystem of Northwest China. We simulated five different scenarios of future rain regimes (0%, 25%, 50%, 75% and 100% increase over local annual mean precipitation) each month from May to September in 2009. We measured RS and RH every three hours on 6 and 16 days after the rain addition, and estimated RA by calculating the difference between RS and RH. We found that rain addition significantly increased the daily mean RS and its components on the two measurement days during the growing season. However, the diurnal pattern was different between the two respiration components. Rain addition significantly increased the daily Q10 value of RH but suppressed that of RA on Day 6. Rain addition had no influence on daily Q10 value of both respiration components on Day 16 when soil moisture was lower. In addition, we observed significantly higher daily Q10 of RH than RA under all five rain addition treatments, indicating that microbial respiration is more temperature sensitive than root respiration in a short-time scale in this desert ecosystem. Thus, partitioning soil respiration into its two components, and analyzing the differential responses of RH and RA to future climate changes should be considered for more accurate predictions of soil respiration and regional carbon cycle in these arid and semiarid regions. 相似文献