全文获取类型
收费全文 | 2805篇 |
免费 | 260篇 |
国内免费 | 121篇 |
专业分类
林业 | 314篇 |
农学 | 192篇 |
基础科学 | 80篇 |
381篇 | |
综合类 | 983篇 |
农作物 | 98篇 |
水产渔业 | 211篇 |
畜牧兽医 | 743篇 |
园艺 | 91篇 |
植物保护 | 93篇 |
出版年
2024年 | 36篇 |
2023年 | 90篇 |
2022年 | 170篇 |
2021年 | 216篇 |
2020年 | 179篇 |
2019年 | 169篇 |
2018年 | 111篇 |
2017年 | 143篇 |
2016年 | 119篇 |
2015年 | 124篇 |
2014年 | 162篇 |
2013年 | 190篇 |
2012年 | 179篇 |
2011年 | 211篇 |
2010年 | 167篇 |
2009年 | 173篇 |
2008年 | 137篇 |
2007年 | 142篇 |
2006年 | 98篇 |
2005年 | 71篇 |
2004年 | 55篇 |
2003年 | 57篇 |
2002年 | 27篇 |
2001年 | 28篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 22篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有3186条查询结果,搜索用时 0 毫秒
141.
《Journal of plant nutrition》2013,36(10-11):2253-2265
Abstract T2 tobacco lines overexpressing soybean ferritin in the plastids (+TPs) or apoplasm (AFs) under the regulation of CaMV 35S promoter were grown on MS nutrient solution. After 1 month growth, statuses of six major divalent‐metals (Ca, Cu, Fe, Mg, Mn, and Zn) were measured in leaves and roots. Both +TPs and AFs showed enhanced growth (max. 1.7×) in leaves than the control line. The Fe contents in leaves of +TPs and AFs were significantly larger (1.9–2.8×) than that of the control line. The other metal contents in leaves of +TPs and AFs were almost the same as or less than those of the control line. In contrast to the result of leaves, the growth enhancement in roots was not clear in +TPs, but in AFs. Also, some of the non‐ferrous metal contents in roots of +TPs and AFs were dramatically increased compared with those of the control line (Mn, 1.9–10.4×; Zn, 1.6–2.3×), whereas the differences in content of Fe, Cu, Ca, and Mg were insignificant. These results demonstrated that the ferritin overexpression in apoplasm was as effective for inducing Fe accumulation as that in plastid. Under the normal metal‐balanced condition, even if the activation of Fe uptake related enzymes leads to the accumulation of non‐specific accumulation of divalent metal ions in roots, an Fe loading/unloading system and/or an internal translocator in xylem and phloem might specifically deliver Fe to the upper part of plants. 相似文献
142.
The effects of seed-borne Fusarium spp. and Microdochium nivale infection in spring wheat, winter wheat, and oats in Sweden was investigated in field trials for the agronomic characters yield, thousand kernel weight, grain volume weight, gluten, protein, starch, straw strength, and plant density. Seed with high and low levels of infection was mixed to obtain six infection levels in the proportions of 100/0, 80/20, 60/40, 40/60, 20/80, and 0/100 percent. The seed was untreated or treated with Celest Extra Formula M (CEFM, difenoconazole + fludioxonil) or Celest Formula M (CFM, fludioxonil). In the field trials using untreated seed, there were significant differences between infection levels only for some agronomic characters and levels. Fungicide seed treatment with CEFM in spring wheat had no significant effect on most agronomic characters including yield. In winter wheat and oats, seed treatment with CFM increased yield by 7–11% and plant density by up to 33% while having no effect on other characters. The percentage discoloration of crown roots and stem bases due to Fusarium/Microdochium spp. was also investigated visually in winter wheat and oats and found to increase with higher infection level. Fungicide seed treatment thus mainly increased plant emergence in seed lots with low-to-moderate Fusarium/Microdochium spp. infection and had little or no effects on other agronomic characters. 相似文献
143.
不同种植模式和土壤类型条件下土壤健康的定量评价 总被引:2,自引:0,他引:2
Soil health assessment is an important step toward understanding the potential effects of agricultural practices on crop yield, quality and human health. The objectives of this study were to select a minimum data set for soil health evaluation from the physical, chemical and biological properties and environmental pollution characteristics of agricultural soil and to develop a soil health diagnosis model for determining the soil health status under different planting patterns and soil types in Chongming Island of Shanghai, China. The results showed that the majority of the farmland soils in Chongming Island were in poor soil health condition, accounting for 48.9% of the survey samples, followed by the medium healthy soil, accounting for 32.2% of the survey samples and mainly distributed in the central and mid-eastern regions of the island. The indicators of pH, total organic carbon, microbial biomass carbon and Cd exerted less influence on soil health, while the soil salinization and nitrate accumulation under a greenhouse cropping pattern and phosphate fertilizer shortage in the paddy field had limited the development of soil health. Dichlorodiphenyltrichloroethanes, hexachlorocyclohexanes and Hg contributed less to soil health index (SHI) and showed no significant difference among paddy field, greenhouse and open-air vegetable/watermelon fields. The difference of the SHI of the three soil types was significant at P = 0.05. The paddy soil had the highest SHI values, followed by the gray alluvial soil, and the coastal saline soil was in a poor soil health condition, indicating a need to plant some salt-tolerant crops to effectively improve soil quality. 相似文献
144.
145.
146.
分析了天保工程不同区域存在的基本矛盾和问题,从面临的众多问题中总结归纳出退化天然林恢复与重建、非木质林产品资源开发利用、天然林近自然采育更新和结构调整、工程区防灾减灾和森林健康状况保持、天然林资源动态时空分析与评价等5个重大而急需解决的技术问题;提出了推广应用现有技术成果、针对新问题设立课题研究和引进国际先进理论技术为工程服务的总体对策;并针对5大问题进行深入分析,提出了人工促进退化天然林恢复、森林近自然经营及健康状态监测等解决问题的关键理论和技术要点。 相似文献
147.
干酪具有极高的营养价值和生物学价值,是全球贸易量最大的乳制品之一。随着消费者饮食结构的调整及对干酪营养价值认识的深化,我国的人均干酪消费量也日渐增加,但仍远落后于世界平均水平。我国的干酪还有很大的市场发展空间。阐述了干酪的营养价值,包括蛋白质及功能性多肽、共轭亚油酸、钙和维生素D等活性成分,论述了干酪在防护龋齿、减重及抗肥胖、降血压、抗动脉粥样硬化、缓解骨质疏松、抗肿瘤细胞增生、抗氧化等方面的健康功能研究进展。同时提出了低脂干酪的感官品质及营养功能改善、益生菌干酪开发、干酪抗肿瘤机制及干酪对人体心血管系统的影响研究等未来干酪营养学的研究方向,为干酪的营养价值科普及我国干酪的产业发展提供助力。 相似文献
148.
介绍了玫瑰花的风味成分、营养价值以及与其相关的各种功能性饮料。玫瑰花作为一种具有保健功能的花卉,有很大的食用价值,可以广泛应用于与其相关的各种保健食品的制作。重点介绍了玫瑰花作为食物原料在保健饮料方面的应用。 相似文献
149.
白桂芬 《农产品加工.学刊》2010,(9):82-83
雪莲果叶含有大量的酚酸、类黄酮等活性成分,具有重要的药用价值。利用雪莲果叶制作雪莲果叶保健茶,对进一步提升种植雪莲果生产效益,增加农民经济收入具有重要意义。介绍了雪莲果叶保健茶的保健功能及其制作工艺。 相似文献
150.
Chong Lu 《Asia Pacific viewpoint》2023,64(1):2-16
Using China Migrants Dynamic Survey Project data from 2012 to 2018, this paper evaluates the causal impact of equalisation of basic public health and medical services on the long-term urban settlement intentions of internal migrants by the difference-in-differences approach. The results reveal that the equalisation of basic public health and medical services has a negative impact on the long-term urban settlement intentions of internal migrants of 4%. Male, middle-aged, and unmarried internal migrants have a much stronger negative response, in terms of long-term urban settlement intentions, to changes in basic public health and medical services. Moreover, more recent internal migrants, those in first-tier cities and those in cities in eastern regions also have a much stronger negative response. Mechanism checks imply that the negative impact on the long-term urban settlement intentions of internal migrants is caused by social integration decline after implementation of equalisation of basic public health and medical services. 相似文献