首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   151篇
  免费   4篇
林业   15篇
农学   14篇
基础科学   2篇
  51篇
综合类   7篇
农作物   8篇
水产渔业   9篇
畜牧兽医   32篇
园艺   8篇
植物保护   9篇
  2023年   3篇
  2022年   5篇
  2021年   8篇
  2020年   3篇
  2019年   4篇
  2018年   12篇
  2017年   10篇
  2016年   11篇
  2015年   5篇
  2014年   9篇
  2013年   17篇
  2012年   12篇
  2011年   11篇
  2010年   8篇
  2009年   2篇
  2008年   6篇
  2007年   4篇
  2006年   5篇
  2005年   2篇
  2004年   1篇
  2003年   2篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1998年   1篇
  1997年   1篇
  1993年   2篇
  1986年   1篇
  1985年   2篇
  1982年   1篇
  1976年   1篇
  1969年   1篇
  1967年   2篇
排序方式: 共有155条查询结果,搜索用时 15 毫秒
121.
The inheritance of siliqua orientation and seed coat colour in Brassica tournefortii was investigated using four genotypes varying in these two characters. The F1, F2 and backcross generations of two crosses were used for studying the segregation pattern of the traits. The plants were classified for seed colour as having brown or yellow seeds and for siliqua orientation as having upright, semi‐spread or spread siliqua. Seed colour was found to be under monogenic control with brown being dominant over yellow. Siliqua orientation was under digenic polymeric gene action: upright siliqua was produced by the presence of two dominant genes and spread siliqua by two recessive genes. The absence of even a single dominant gene resulted in a third type of siliqua orientation, semi‐spread siliqua.  相似文献   
122.
The interior forest of protected area(PA)recover quickly in terms of greater diversity and structural complexity than peripheral and outsides, which may be due to high plant-frugivore interactions in the interior forest than the disturbed outsides. To describe the structural and functional differences in tree communities from interior to outside forests with in small PA, we quantitatively analyzed the vegetation of Trishna Wildlife Sanctuary, a rich primate habitat of Northeast India. Vegetation was sampled at C10 cm girth at breast height by 10 m 9 500 m sized20 line transects(10 ha) laid in the interior(N = 7),peripheral(N = 7) and outside(N = 6) zones of this sanctuary. All transects were ordinated by Principal Component Analysis based on correlation between diversity and existing disturbance indices. We found significant differences(P \ 0.05) in taxonomic richness and diversity indices between the habitat. Van diagram confirmed greater unique species richness in the interior zone(64) than peripheral(28) and outside(6) zones. Overall density(ha-1) did not differed across the zones, but basal area(m2ha-1) was significantly(P \ 0.01) high in peripheral zone. Vertical distribution of stem density was linearly declined across zones(r2adj[ 0.70; P \ 0.01) with increase in the canopy height. Horizontal distribution of adult stems showed significant inverse quadratic relationship(r2adj[ 0.80; P \ 0.001), which suggests very low density of canopy forming voluminous trees in the interior zone.Immediate protection, restoration and management of interior regions are required to preserve local plant genetic diversity and also to maintain suitable habitat for threatened wildlife.  相似文献   
123.
The influence of dual inoculation of arbuscular mycorrhizal fungi (AMF) and Rhizobium was assessed on garden pea productivity, root morphology and soil fertility during 2011–2012 at Palampur, India, in a medium phosphorus (P) acid Alfisol. Field experimentation comprised 13 treatments involving Rhizobium, AMF and inorganic fertilizers in (RBD) replicated thrice. The dual inoculation of Rhizobium and AMF exhibited nominal effect on pea pod length, pod girth and number of seeds per pod. However, average pod weight (APW) and productivity increased by 14.1 and 20% following dual inoculation, respectively, over generalized recommended nitrogen, phosphorus and potassium (NPK) dose general recommended dose (GRD). Dual inoculation of pea seed with both symbionts sharply increased the root volume (RV), root dry weight (RDW), root weight density (RWD) and root nodules per plant by 34.5, 13.3, 13 and 44%, respectively. Similarly, the highest AMF root colonization was registered under dual-inoculated plots compared to sole application of Rhizobium or AMF. Different treatments including dual-inoculated ones did not alter the soil organic carbon (SOC), available N, K and diethylenetriaminepentaacetic acid (DTPA)-extractable micronutrients iron, zinc, copper and manganese (Fe, Zn, Cu and Mn) status significantly; however, a nominal buildup in the above-mentioned parameters was registered under dual inoculation. Available P status increased to the tune of 6.7 and 8.7% following dual inoculation with Rhizobium and AMF over their respective sole inoculations. Overall, the current study suggests that Glomus–Rhizobium symbiosis has great potential in enhancing productivity through better proliferation of the root system and improved soil fertility status. Furthermore, dual inoculation of AMF and Rhizobium can save up to 25% fertilizer N and P in garden pea in acid Alfisol of the northwestern Himalayas (NWH).  相似文献   
124.
Present investigation studied plant water relations and soil physical properties through AM fungi (Glomus mosseae) to mitigate drought stress in Himalayan acid Alfisol having low water retentivity. Experimentation was carried out at Palampur, India during 2009–2011 in okra–pea cropping system in randomized block design (RBD) replicated thrice with 14 treatments comprising arbuscular mycorrhizal (AM) fungi, varying phosphorus nutrition and irrigation regimes at 40 and 80% available water holding capacity. Integrated use of AM fungi at varying phosphorus (P) levels and irrigation regimes led to significantly higher relative leaf water content (3% each) in okra and pea besides significantly higher xylem water potential (27%) in pea over non-AM fungi counterparts. AM fungi enhanced water-use-efficiency in okra (5–17%) and pea (12–35%) over non–AM fungi counterparts. AM fungi also improved water holding capacity (5–6%) and mean weight diameter of soil particles (4–9%) over non–AM fungi counterparts; but, had nominal or no effect on bulk density. Mycorrhizal plants maintained higher tissue water content imparting greater drought resistance to plants over non–mycorrhizal plants at moisture stress. It is inferred that integrated application of AM fungi and P at varying irrigation regimes improved the plant water relations vis-à-vis drought resistance, crop productivity, WUE, soil aggregation and water holding capacity in okra–pea sequence in Himalayan acid Alfisol.  相似文献   
125.
126.
127.
128.
An entomopathogenic fungus belonging to the genus Hirsutella was found infecting the mango hopper, Idioscopus clypealis (Lethierry) (Hemiptera: Cicadellidae), for the first time in India in September 2011. The report of a natural control agent of mango hopper during the off season has special significance because its outbreak depends upon its residual hibernating population.  相似文献   
129.
Cereal cropping productivity in the Indo‐Gangetic Plain (IGP) of India is declining, which may be overcome by diversification, alternate crop establishment methods and mulching. This study was conducted to determine whether no‐till flat (NTF), permanent raised beds (PRB) and nontraditional ex situ mulching would improve crop and water productivity, economic profitability and soil biological properties in an irrigated maize (Zea mays)–wheat (Triticum aestivum) system (MWS). NTF systems produced 10% higher economic net returns compared with PRBs. Non‐traditional mulching (Sesbania, Jatropha and Brassica) increased yields by >10% and net returns by >12% compared with no‐mulch. The water saving in PRBs compared with NTF systems was 79, 94 and 173 mm/ha in maize, wheat and MWS, respectively. PRBs saved 29.2% of irrigation water and improved the MWS irrigation water productivity (WPI) by 24.5% over NTF. On average, mulching saved 23.8 mm/ha irrigation water over no‐mulch and improved WPI by 12.0%. PRBs with ex situ mulching produced wheat and maize equivalent system yields lower than NTF but improved WPI and soil biological properties. Jatropha and Sesbania mulching improved yield, water saving, WPI and system profitability. In limited irrigation and no crop residue availability conditions, Sesbania, Jatropha and Brassica vegetation material have potential applications for ex situ mulching under PRBs for water saving and NTF for productivity.  相似文献   
130.
Tropical Animal Health and Production - Murrah buffalo heifers (live weight 135?±?17 kg) were fed a total mixed ration without supplementation (CON), or supplemented with...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号