全文获取类型
收费全文 | 416篇 |
免费 | 18篇 |
国内免费 | 33篇 |
专业分类
林业 | 15篇 |
农学 | 49篇 |
基础科学 | 16篇 |
43篇 | |
综合类 | 193篇 |
农作物 | 46篇 |
水产渔业 | 12篇 |
畜牧兽医 | 37篇 |
园艺 | 30篇 |
植物保护 | 26篇 |
出版年
2024年 | 2篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 20篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 21篇 |
2014年 | 28篇 |
2013年 | 27篇 |
2012年 | 35篇 |
2011年 | 44篇 |
2010年 | 31篇 |
2009年 | 36篇 |
2008年 | 32篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 3篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
排序方式: 共有467条查询结果,搜索用时 78 毫秒
31.
32.
绿色荧光蛋白基因gfp在苏云金芽胞杆菌中表达的初步研究 总被引:2,自引:0,他引:2
将携带蜡状芽胞杆菌特异启动子的gfpmut3a基因克隆到穿梭载体pHT30 4后 ,电转化至苏云金芽胞杆菌BMB171,CryB、IPS78 11、4Q7、HD 80 2 1中。通过荧光显微镜和Bio assayReader对含重组质粒pGFP 30 4的 5个受体菌分别进行荧光检测及定量分析。结果表明 ,gfpmut3a基因仅在苏云金芽胞杆菌无晶体突变株BMB171、CryB、IPS78 11、4Q7中表达并可检测得到菌体发光 ,并建立了一套适合于苏云金芽胞杆菌的GFP标记与检测方法。 相似文献
33.
短季棉子叶荧光动力学及SOD酶活性的研究 总被引:12,自引:2,他引:12
短季棉早熟不早衰类型品种中棉16的可变荧光(Fv)、第二波(S-M)持续时间长,比早衰型晚5天消失,说明其光合磷酸化,CO#-2同化能力和PSⅡ、PSⅠ间电子传递能力强。同时叶绿素降解速度缓慢。SOD酶前期活性高,后期下降快,使之既早熟又不早衰。早熟早衰型品种中棉10的Fv、S-M最先消失,叶绿素降解速度快,SOD酶活性在整个暗处理过程一直最低,说明清除有害自由基能力差,故早熟又过早衰老。晚熟型辽棉7的荧光动力学过程,叶绿素降解速度以及前期SOD酶活性居中,但其中叶绿素绝对含量在衰老全过程中居首位。后期SOD酶活性高于其他品种,这可能与延缓衰老及晚熟有关。 相似文献
34.
[目的]为农药污染的治理提供有价值的参考和依据。[方法]在pH值6.40的Clark-Lubs缓冲溶液中,加入碱性藏花红(ST)与一定浓度的十二烷基苯磺酸钠(SDBS),测定荧光强度,再加入有机磷农药,检测荧光强度变化,据此建立测定有机磷农药残留总量的新方法。[结果]有机磷农药残留总量荧光法测定的优化条件为:在室温下,以ST+SDBS为反应体系,ST浓度为5.0×10-6mol/L,SDBS浓度为9.0×10-4mol/L,缓冲溶液pH值为6.40,缓冲溶液用量为1.0 ml,溶液中甲醇的用量控制在10%以内。[结论]试验所建立的测定方法已成功用于土壤中有机磷农药残留总量的检测。 相似文献
35.
吲唑酯是一种新的植物生长调节剂,对于它的分析国内尚未见报道.为了探讨吲唑酯的稳定性和残留量,我们对分析方法进行了研究,发现吲唑酯有明显的荧光现象,测定了它的标准激发光谱和荧光光谱谱图,并由此鉴定了我院合成的吲唑酯。利用高效液相色谱紫外、荧光双检测器双通道检测,对吲唑酯及乳剂进行了定量分析,同一样品紫外和荧光检测结果基本一致,由此确立了一套从固体样品、乳剂到极低浓度溶液的色谱、光谱测定条件。方法优越性:样品不需预处理,用量极少(几微毫),快速(几分钟),干扰很少(尤其荧光检测),线性范围宽(可达10~5),检测下限很低(荧光可达1ppb)。分析结果表明,吲唑酯乳剂存放3年含量稍有下降。 相似文献
36.
肉鸡心脏热应激损伤和热休克蛋白mRNA转录水平的相关性 总被引:7,自引:1,他引:7
通过分光光度计、组织病理学和荧光定量反转录PCR检测技术,研究肉鸡心脏热应激损伤和热休克蛋白mRNA 变化的相关性。试验结果显示,热应激过程中肌酸激酶和谷丙转氨酶的活性呈现波动性变化,肌酸激酶的变化更明显;心脏的组织病理学变化主要表现为心肌纤维变性和坏死;热应激过程中HSC70 mRNA也呈现波动性变化,而 HSP70 mRNA水平呈现上升趋势。结果提示,HSC70 mRNA与肌酸激酶活性变化呈现一定负相关,HSC70有可能作为心脏热应激损伤的标志物。 相似文献
37.
用荧光显微镜技术观察药用野生稻(Oryza officinalis Wall)和转基因水稻的不亲和性 总被引:9,自引:0,他引:9
采用荧光显微镜技术观察转基因水稻花粉在药用野生稻柱头上的萌发及在花柱内的生长过程,以明确两者之间不亲和性发生的阶段,为判断其能否发生基因漂流提供依据。结果表明,两种转基因栽培稻(Y003和99t)的花粉在药用野生稻柱头上的萌发率均比药用野生稻自花授粉的低,花粉管在花柱中的生长速度较慢,且分别在到达花柱中部(Y003)或花柱基部(99t)时停止生长,顶端异常膨大,杂交子房逐渐萎缩,结实率为0。药用野生稻与栽培稻杂交不亲和的原因是花粉管在花柱中停止生长、不能进入胚囊完成受精,在自然条件下转基因栽培稻中的外源基因 相似文献
38.
Response of hot pepper (Capsicum annuum L.) to mulching practices under planted greenhouse condition
Yin-Li Liang Xing WuJuan-Juan Zhu Mao-Juan ZhouQiang Peng 《Agricultural Water Management》2011,99(1):111-120
Mulch is considered a desirable management technology for conserving soil moisture, improving soil temperature and soil quality. This study aimed to investigate soil conditions and hot pepper (Capsicum annuum L.) performance in terms of leaf photosynthetic capacity, fruit yield and quality, and irrigation water use efficiency (IWUE) under such practices in greenhouse condition. A field experiment across 3 years was carried out with four types of mulch (without mulch [CK], wheat straw mulch [SM], plastic film mulch [FM], and combined mulch with plastic film and wheat straw [CM]). Mulch could improve soil physical properties regardless of mulch materials. FM and CM treatments improved soil moistures status and soil temperature in comparison to CK control, while SM increased soil water content and decreased soil temperature. Mulch increased leaf net photosynthesis rate (PN), stomatal conductance to water vapor (gs), intercellular CO2 concentration (Ci), and transpiration rate (E), but declined instant water use efficiency (WUEi). No significant effect of mulch application on chlorophyll fluorescence was existent for the entire growth season. Fruit yield and irrigation water use efficiency (IWUE) showed some increment under all the mulch conditions. Compared to CK, the yield was enhanced by 82.3%, 65.0%, and 111.5% in 2008; 38.1%, 17.4%, and 46.5% in 2009; and 14.3%, 6.5%, and 19.6% in 2010 under SM, FM, and CM conditions, respectively. Although FM produced better fruit quality than other treatments, CM is the recommended practice for hot pepper cultivation in greenhouse condition due to working well to facilitate soil condition (moisture and temperature), plant growth, and marketable yield. 相似文献
39.
40.
The biodegradation of polycyclic aromatic hydrocarbons (PAHs) via free-living and attached micro-organisms in soil/water systems was observed in order to examine the variability in the community dynamics and physiological profiles of the micro-organisms. As determined by fluorescence in situ hybridization (FISH), the Domain Bacteria, consisting of three phyla α-, β- and γ-Proteobacteria, reached 41.27–56.05% of all organisms in the soil/water system for PAH biodegradation. Among the free-living species, Proteobacteria, including Brevundimonas (Pseudomonas) diminuta, Caulobacter spp., Mycoplana bullata, Acidovorax spp. and Pseudomonas aeruginosa were found to be dominant—making up 93.51–99.80% of the population—and therefore seem to be associated with PAH biodegradation. Total plate count numbers and the count of Pseudomonas sp. present in the free-living population increased to between 103 and 106 CFU ml−1 when clay with very low organic matter content was used as the matrix for PAH degradation. However, total plate count microbial numbers increased to only 101–102 CFU ml−1 using natural soil from Taichung containing 1.883% organic matter. The soil organic content (SOM) seemed to affect the mass transfer of PAH in soil, leading to the difference in PAH biodegradation. Two different approaches, which included community-level physiological profiling (CLPP) and ectoenzymatic activities, were used to explain the functional diversity between free-living and attached bacteria. The free-living and attached bacterial communities from the clay system showed proportionately greater differences using CLPP. Relatively high levels of esterases, aminopeptidases and some specific glycolysis-gluconeogenesis enzymes gave an identifiable correlation with PAH biodegradation. The differences in bacterial composition, numbers and physiological characteristics show that free-living and attached micro-organisms may play different biochemical roles in PAH degradation in soil. 相似文献