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   261016篇
  免费   18583篇
  国内免费   6265篇
林业   29803篇
农学   24293篇
基础科学   8568篇
  47574篇
综合类   27791篇
农作物   19242篇
水产渔业   17255篇
畜牧兽医   77228篇
园艺   7969篇
植物保护   26141篇
  2022年   2299篇
  2021年   4350篇
  2020年   4988篇
  2019年   4686篇
  2018年   4892篇
  2017年   6015篇
  2016年   6368篇
  2015年   6671篇
  2014年   7911篇
  2013年   19099篇
  2012年   8651篇
  2011年   10420篇
  2010年   10537篇
  2009年   10858篇
  2008年   9120篇
  2007年   8537篇
  2006年   9098篇
  2005年   8058篇
  2004年   6180篇
  2003年   5739篇
  2002年   4771篇
  2001年   5325篇
  2000年   5329篇
  1999年   5662篇
  1998年   5227篇
  1997年   5056篇
  1996年   4829篇
  1995年   5382篇
  1994年   4638篇
  1993年   4277篇
  1992年   4040篇
  1991年   4057篇
  1990年   3601篇
  1989年   3400篇
  1988年   2997篇
  1987年   2981篇
  1986年   2689篇
  1985年   2994篇
  1984年   2977篇
  1983年   2887篇
  1982年   2561篇
  1981年   2519篇
  1980年   2499篇
  1979年   2434篇
  1978年   2311篇
  1977年   2201篇
  1976年   2050篇
  1975年   1802篇
  1974年   1821篇
  1973年   1732篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Journal of Plant Diseases and Protection - Gerbera is an important cut flower crop popular throughout the world. In summer months of 2016, gerberas grown in polyhouses of RHREC, GKVK, Bengaluru,...  相似文献   
2.
Journal of Plant Diseases and Protection - The neotropical brown stink bug Euschistus heros (F.) is an important pest for many crops in several countries and its ability to survive on associated...  相似文献   
3.
Asian grapevine leaf rust (AGLR) causes severe crop losses in Brazilian viticulture, mainly in latitudes <25°S. The purpose of this study was to identify the pathogen(s) involved with AGLR in Brazil, based on phylogenetic and morphological analysis and pathogenicity tests. In total, 56 monouredinial isolates from six Brazilian states were identified using the internal transcribed spacer 2 and the large subunit rRNA gene D1/D2 regions. All 50 isolates from the south-central region were classified as Neophysopella tropicalis, and the other six isolates from the north-east region as Neophysopella meliosmae-myrianthae. This result provides evidence that two pathogen introductions from different sources may have occurred in the country. For both species, paraphyses were cylindrical, incurved, aseptate, and hyaline, while urediniospores were short-pedicellate, obovoid or obovoid-ellipsoid, with the wall colourless or pale yellowish, evenly echinulate. Representative isolates from both species caused typical AGLR symptoms on Vitis vinifera 'Merlot' and V. labrusca 'Niagara Rosada'. Overall, regardless of the Neophysopella species, isolates caused similar leaf disease severities. Higher disease severity was observed in Niagara Rosada (average of 40.3% of diseased leaf area) compared to Merlot (20.5%). This study reports, for the first time, the characterization of Neophysopella species associated with AGLR in Brazil.  相似文献   
4.
Journal of Plant Diseases and Protection - Fall armyworm, Spodoptera frugiperda (Noctuidae: Lepidoptera), is an economically important invasive pest infesting maize. Habitat manipulation as a...  相似文献   
5.
Phytoparasitica - Root and crown rot (RCR) caused by Phytophthora capsici is present in all crop production areas of pepper and chili worldwide. This pathogen was recently reported at the Pacific...  相似文献   
6.
Cold plasma, an ionized gas produced by applying an electrical current to air, can be used to produce plasma-activated water (PAW), which has excellent antimicrobial properties. In this study PAW was applied to conidia of Colletotrichum alienum to investigate its impact on conidial germination in vitro. PAW was produced by treating tap, deionized, or distilled water with cold plasma for 30 or 60 min to produce PAW30 or PAW60, each of which was then incubated for up to 24 hr with a conidial suspension of C. alienum in a ratio of 1:1, 1:2, or 1:3 (conidial suspension:PAW), and the percentage germination measured. The greatest reduction in germination occurred when conidia were incubated with PAW60 produced from deionized water or distilled water, for all ratios. For PAW30, deionized water was the most effective for all three ratios, and on this basis, deionized water was selected for all further experiments. PAW produced from smaller volumes of water and at shorter distances from the cold plasma source was more effective at reducing germination. Treatment of conidia with acidified water was not as effective as PAW at inhibiting germination. Nitrates and nitrites were present in the PAW in varying concentrations and may have contributed to the inhibition of germination. PAW retained activity and reduced germination even after storage for 15 days. These findings demonstrate the potential of PAW as a novel treatment for postharvest fungal pathogens.  相似文献   
7.
Ahmad  Gufran  Khan  Abrar A.  Mohamed  Heba I. 《Gesunde Pflanzen》2021,73(4):623-637

Acid rain is one of the major environmental problems that causes plant morphological and physiological disorders. But there are few studies about the impact of acid rain on vegetable crops. This work aimed to study the various effects of simulated acid rain (SAR) at different levels of pH (5.0, 4.5, 4.0, 3.5 or 3.0) on growth, yield, pigment content, protein, carbohydrate, water content in leaves, minerals (NPK), oxidative damage and the activity of various antioxidants in pumpkin. The results show that the plant growth, yield, chlorophyll, carotenoids, protein, carbohydrates, leaf water content, NPK in the leaves of the pumpkin crop decreased significantly with increasing levels of acidity of SAR as compared to the untreated set. H2O2 and MDA are increased by SAR treatment which depends on the level of pH value of SAR. The highest value of hydrogen peroxide and malondialdehyde was recorded at pH 3.0 and lower at pH 5.0 of SAR treatment on the pumpkin crop. In contrast, superoxide dismutase, catalase, nitrate reductase and proline contents were accumulated at pH 3.0 and degraded at pH 5.0 of SAR treatment on pumpkin as compared to control. In conclusion, our findings suggest that pumpkin produces more reactive oxygen species (ROS) scavenging SAR stress through the production of enzyme and non-enzyme antioxidant compounds at 3.0 pH. Meanwhile, growth inhibition as well as the photosynthesis of pumpkin and the magnitude of oxidative damage increased as acidity increased (pH 3.0 of SAR).

  相似文献   
8.
European Journal of Plant Pathology - There are few studies of cucumber roots at the seedling stage infected by Pseudomonas amygdali pv. lachrymans (Pal). We used growth chamber assays to determine...  相似文献   
9.
Journal of Plant Diseases and Protection - Recombinase Polymerase Amplification (RPA) assay was developed for specific detection of Tomato leaf curl New Delhi virus-potato (ToLCNDV [potato]),...  相似文献   
10.
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