全文获取类型
收费全文 | 835篇 |
免费 | 50篇 |
国内免费 | 25篇 |
专业分类
林业 | 23篇 |
农学 | 49篇 |
基础科学 | 16篇 |
54篇 | |
综合类 | 268篇 |
农作物 | 72篇 |
水产渔业 | 3篇 |
畜牧兽医 | 93篇 |
园艺 | 10篇 |
植物保护 | 322篇 |
出版年
2024年 | 4篇 |
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 19篇 |
2020年 | 30篇 |
2019年 | 28篇 |
2018年 | 16篇 |
2017年 | 40篇 |
2016年 | 46篇 |
2015年 | 25篇 |
2014年 | 51篇 |
2013年 | 63篇 |
2012年 | 60篇 |
2011年 | 55篇 |
2010年 | 27篇 |
2009年 | 39篇 |
2008年 | 35篇 |
2007年 | 41篇 |
2006年 | 36篇 |
2005年 | 40篇 |
2004年 | 39篇 |
2003年 | 38篇 |
2002年 | 21篇 |
2001年 | 27篇 |
2000年 | 11篇 |
1999年 | 19篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 6篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1991年 | 4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 |
1982年 | 2篇 |
排序方式: 共有910条查询结果,搜索用时 15 毫秒
31.
Orobanche amethystea Thuill.,O. loricata Reichenb. andO. pubescens D’Urv. were found to parasitize the roots of cultivated plants in Israel.Orobanche pubescens is known from the local flora, and was now found to cause damage in parsley fields and toTropaeolum majus L. (nasturtium) in ornamental gardens.Orobanche amethystea andO. loricata are known as occasional weeds in Europe and were recently found for the first time in Israel.Orobanche amethystea densely populated vetch fields in Israel, andO. loricata was found in ornamental gardens. A key for the identification ofOrobanche species in cultivated areas in Israel is given, based on morphological features.
http://www.phytoparasitica.org posting Jan. 13, 2002. 相似文献
32.
在2001~2002年两年间,应用百草敌、2,4-D丁酯乳油、2-甲-4-氯丙酸及混合药剂对青海大学农牧学院草业科学系试验地草坪杂草进行防除试验。结果表明:百草敌、2,4-D丁酯乳油及混合药剂I对几种主要杂草防除效果比较好,与对照相比30 d能达100%,而且两种混合药剂有增效作用,扩大了除草剂的使用范围。 相似文献
33.
Grass species were grown in plots, as pure stands or mixed with wheat, after a sequence of wheat crops in which take-all ( Gaeumannomyces graminis var. tritici ) had developed. Annual brome grasses maintained take-all inoculum in the soil as well as wheat (grown as a continuous sequence), and much better than cultivated species with a perennial habit. Take-all developed more in wheat grown after Anisantha sterilis (barren brome) or Bromus secalinus (rye brome), with or without wheat, than in continuous grass-free wheat in the same year, where take-all decline was apparently occurring. It was equally or more severe, however, in wheat grown after Lolium perenne (rye-grass) or Festuca arundinacea (tall fescue), despite these species having left the least inoculum in the soil. It was most severe in plots where these two grasses had been grown as mixtures with wheat. It is postulated that the presence of these grasses inhibited the development of take-all-suppressive microbiota that had developed in the grass-free wheat crops. The effects of the grasses appeared to be temporary, as amounts of take-all in a second subsequent winter wheat test crop were similar after all treatments. These results have important implications for take-all risk in wheat and, perhaps, other cereal crops grown after grass weed-infested cereals or after set-aside or similar 1-year covers containing weeds or sown grasses, especially in combination with cereal volunteers. They also indicate that grasses might be used experimentally in wheat crop sequences for investigating the mechanisms of suppression of, and conduciveness to, take-all. 相似文献
34.
Anna Johansson Jan-Kees C. Goud Christina Dixelius 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(2):139-149
Verticillium longisporum is a soil-borne fungal pathogen causing vascular wilt of Brassica crops. This study was conducted to enhance our knowledge on the host range of V. longisporum. Seven crop species (barley, oat, oilseed rape, pea, red clover, sugar beet and wheat) and five weed species (barren brome,
black-grass, charlock, cleavers and scentless mayweed) all common in southern Sweden were evaluated for infection by response
to V. longisporum. Oat, spring wheat, oilseed rape, scentless mayweed and charlock inoculated with V. longisporum in a greenhouse showed stunting to various degrees close to the fully ripe stage. Based on the extent of microsclerotia formation,
explants were separated into four groups: for pea and wheat, <5% of the samples had formed microsclerotia; for scentless mayweed,
5–10%; for oat, 10–20%; and for charlock and oilseed rape >80%. The results suggest that plant species outside the Brassicaceae can act as reservoirs of V. longisporum inoculum. Soil inoculum densities in nine fields were monitored over a period of 12 months, which ranged from 1 to 48 cfu
g−1 soil. Density of microsclerotia was lowest just after harvest, reaching its maximum six months later. No significant correlation
between inoculum density in soil and disease incidence on oilseed rape plants was found. However, the data suggest that a
threshold of 1 cfu g−1 soil is needed to cause disease on oilseed rape. Species identification based on microsclerotia morphology and PCR analysis
showed that V. longisporum dominated in soil of seven, and V. dahliae in two of the nine fields studied. 相似文献
35.
36.
通过对贵德县常牧乡切扎村毒草危害状况的调查,毒草危害面积为0.63×104hm2,基本摸清了其分布情况及危害程度,并提出了防治建议,对于今后开展防治工作具有指导意义。 相似文献
37.
38.
R. J. Hillocks 《Integrated Pest Management Reviews》1998,3(3):155-167
Weed control is one of the most important crop protection activities undertaken in both intensive and low-input farming systems. However, even under intensive systems, crop protection which is less dependent on pesticides may require that weeds be managed to obtain a balance between crop and non-crop vegetation to encourage an increase in natural enemies of crop pests. In the low-input farming systems which sustain much of the rural population of Africa, weed control is usually done by hand and clean weeding is often beyond the labour resources of the farming family. The vegetational diversity of peasant agriculture in Africa to which weeds make their contribution, helps to decrease the risk of disease and pest epidemics. In addition to the pest control benefits of a diverse agroecosystem, weeds contribute to the resource base of the rural community, providing a source of secondary foods, medicines and insecticides. Weed control within an integrated crop protection system appropriate to the needs of the resource-poor farmer, requires that weeds are managed in such a way that their biodiversity is maintained and the more useful species retained within the field or field margin. Those weeds with high food potential or which have pesticidal or medicinal properties might be deliberately encouraged within the crop or field margins. Certain weed species may harbour important pests or diseases of local crops and therefore should be selectively removed. The paper reviews and discusses the literature on the beneficial and deleterious effects of weeds and argues for a weed management strategy which balances the effects of weed competition on crop production with the ethnobotanical and pest control attributes of individual weed species and weed communities. 相似文献
39.
T. J. Hodgson 《Southern Forests》2013,75(1):37-42
An N-P-K fertilizer trial with Pinus elliottii was analysed to provide regression equations of height and dry mass on soil nutrient levels. Response surfaces and isoquants were plotted. The technique is used to demonstrate the derivation of fertilizer recommendations for the raising of seedlings to predetermined standards. 相似文献
40.
《Journal of Crop Improvement》2013,27(2):43-119
Summary The importance, characteristics, positive and negative impacts, and future role of weeds as an integral part of the natural and agroecosystems are evaluated and discussed. Interference between plants in nature and the importance of differentiating between competition and allelopathy are interpreted. Allelopathy as one component of weed/crop interference, allelochemicals from weed species and their possible mechanism of action are listed and discussed. Weed species with inhibitory action against cultivated crops, other weed species, and plant pathogens, as well as self-inhibitory (autopathic) species are reviewed. Stimulatory or inhibitory allelopathic effects of different crop plants, trapping and catching species, and the potential of allelopathic weeds in inhibiting or stimulating certain parasitic weed species are discussed and evaluated. Allelopathy as a mechanism and future strategy for agricultural pest control and farm management and the potential use and development of some allelochemicals as natural pesticides or plant growth regulators are also considered and discussed. 相似文献