全文获取类型
收费全文 | 737篇 |
免费 | 35篇 |
专业分类
林业 | 92篇 |
农学 | 19篇 |
基础科学 | 5篇 |
281篇 | |
综合类 | 71篇 |
农作物 | 16篇 |
水产渔业 | 30篇 |
畜牧兽医 | 185篇 |
园艺 | 14篇 |
植物保护 | 59篇 |
出版年
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 12篇 |
2020年 | 13篇 |
2019年 | 16篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 16篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 48篇 |
2012年 | 34篇 |
2011年 | 45篇 |
2010年 | 26篇 |
2009年 | 22篇 |
2008年 | 41篇 |
2007年 | 46篇 |
2006年 | 38篇 |
2005年 | 32篇 |
2004年 | 33篇 |
2003年 | 35篇 |
2002年 | 31篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 15篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1991年 | 7篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 10篇 |
1982年 | 4篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1972年 | 7篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1969年 | 6篇 |
1968年 | 3篇 |
1967年 | 7篇 |
1966年 | 5篇 |
1965年 | 6篇 |
1963年 | 3篇 |
排序方式: 共有772条查询结果,搜索用时 62 毫秒
771.
Arsenic in Rice Soils and Potential Agronomic Mitigation Strategies to Reduce Arsenic Bioavailability: A Review 总被引:1,自引:0,他引:1
Soils used for rice (Oryza sativa L.) cultivation in some areas contain high concentrations of arsenic (As) due to irrigation with groundwater containing As and intensive use of agrochemicals or industrial residues containing As. To restrict rice uptake of As in these soils, approaches to reduce As input and bioavailability must be considered. One approach to reduce As input into rice soils or uptake by rice is cultivating rice under aerobic, intermittent flooding, or alternate wetting and drying (AWD) conditions, rather than in submerged soils, or use of irrigation water low in As. For reducing As bioavailability in soil, aerobic or AWD rice culture and application of biochar, sulfur (S), and/or rice polish to soil are promising. Moreover, use of As-hyperaccumulating plant species (e.g., Pteris vittata L.) in rotation or combinations with favourable plant species (e.g., Azolla, Chlorella, or Nannochloropsis species) can also be promoted, in addition to using rice cultivars that are tolerant to As. Though applications of high doses of phosphorus (P), iron (Fe), and silicon (Si) fertilizers have shown promise in many instances, these methods have to be practiced carefully, because negative effects have also been reported, although such incidents are rare. Major factors affecting As speciation and bioavailability in soil are chemical properties such as redox status, pH, and Fe, P, Si, and S concentrations, physical properties such as texture and organic matter, and biological properties such as methylation activity by soil microorganisms. However, as many of these factors interact, long-term examination under field conditions is needed before measures are recommended for and implemented in farmers' fields. 相似文献
772.
The role of soil chemical properties,land use and plant diversity for microbial phosphorus in forest and grassland soils
下载免费PDF全文
![点击此处可从《植物养料与土壤学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Elisabeth Sorkau Steffen Boch Runa S. Boeddinghaus Michael Bonkowski Markus Fischer Ellen Kandeler Valentin H. Klaus Till Kleinebecker Sven Marhan Jörg Müller Daniel Prati Ingo Schöning Marion Schrumpf Jan Weinert Yvonne Oelmann 《植物养料与土壤学杂志》2018,181(2):185-197
Management intensity modifies soil properties, e.g., organic carbon (Corg) concentrations and soil pH with potential feedbacks on plant diversity. These changes might influence microbial P concentrations (Pmic) in soil representing an important component of the P cycle. Our objectives were to elucidate whether abiotic and biotic variables controlling Pmic concentrations in soil are the same for forests and grasslands, and to assess the effect of region and management on Pmic concentrations in forest and grassland soils as mediated by the controlling variables. In three regions of Germany, Schwäbische Alb, Hanich‐Dün, and Schorfheide‐Chorin, we studied forest and grassland plots (each n = 150) differing in plant diversity and land‐use intensity. In contrast to controls of microbial biomass carbon (Cmic), Pmic was strongly influenced by soil pH, which in turn affected phosphorus (P) availability and thus microbial P uptake in forest and grassland soils. Furthermore, Pmic concentrations in forest and grassland soils increased with increasing plant diversity. Using structural equation models, we could show that soil Corg is the profound driver of plant diversity effects on Pmic in grasslands. For both forest and grassland, we found regional differences in Pmic attributable to differing environmental conditions (pH, soil moisture). Forest management and tree species showed no effect on Pmic due to a lack of effects on controlling variables (e.g., Corg). We also did not find management effects in grassland soils which might be caused by either compensation of differently directed effects across sites or by legacy effects of former fertilization constraining the relevance of actual practices. We conclude that variables controlling Pmic or Cmic in soil differ in part and that regional differences in controlling variables are more important for Pmic in soil than those induced by management. 相似文献