全文获取类型
收费全文 | 1491篇 |
免费 | 72篇 |
国内免费 | 259篇 |
出版年
2023年 | 26篇 |
2022年 | 32篇 |
2021年 | 45篇 |
2020年 | 55篇 |
2019年 | 53篇 |
2018年 | 41篇 |
2017年 | 51篇 |
2016年 | 48篇 |
2015年 | 50篇 |
2014年 | 66篇 |
2013年 | 91篇 |
2012年 | 44篇 |
2011年 | 78篇 |
2010年 | 50篇 |
2009年 | 54篇 |
2008年 | 82篇 |
2007年 | 87篇 |
2006年 | 71篇 |
2005年 | 56篇 |
2004年 | 61篇 |
2003年 | 57篇 |
2002年 | 49篇 |
2001年 | 48篇 |
2000年 | 47篇 |
1999年 | 42篇 |
1998年 | 44篇 |
1997年 | 37篇 |
1996年 | 25篇 |
1995年 | 42篇 |
1994年 | 38篇 |
1993年 | 35篇 |
1992年 | 23篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 15篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 12篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1974年 | 8篇 |
排序方式: 共有1822条查询结果,搜索用时 31 毫秒
121.
稻瘟病菌致病突变体的REMI诱变与鉴定 总被引:2,自引:0,他引:2
以水稻“爱知旭”(Aichi—aShahi)为寄主,将带选择标记的质粒pCSN43和pBF101为外源DNA,利用限制酶诱导整合(REMI)这种新方法转化稻瘟病菌原生质体,从筛选到的数百个转化体中分离出3个与致病能力密切相关的突变体R2H65、R2H69和R281565。其中,R2H65和R2H69只产生畸形分生孢子,分生孢子的发育和附着胞的形成以及黑色素的合成均受到极大影响,致病性测试证明完全丧失致病能力;R281565的许多表型与野生型的相似,但致病能力却大大降低。 相似文献
122.
A Device for Infecting Adult Tsetse Flies,Glossinaspp., with an Entomopathogenic Fungus in the Field
Nguya K Maniania 《Biological Control》1998,11(3):248-254
Various chamber designs for infecting natural populations ofGlossina pallidipes, G. longipennis,andG. fuscipes fuscipeswith the entomopathogenic fungusMetarhizium anisopliaewere tested in the field. All three species of tsetse flies entered the chambers and became infected with the fungus. Mortality attributed to infection byM. anisopliaeranged from 0 to 76% forG. pallidipes/G. longipennisand from 0 to 80% forG. fuscipes.One design proved to be more efficient than the others in permitting the passage of flies and contaminating them with fungal conidia. Dry conidia ofM. anisopliaein the infection chamber retained their infectivity for more than 21 days in the field. 相似文献
123.
124.
Yoshikazu Horie Dong Mei Li Toshimitu Fukiharu Ruoyu Li Paride Abliz Kazuko Nishimura Duan Li Wang 《Mycoscience》1998,39(2):161-165
Emericella appendiculata, a new species isolated from soil of the Pamire Plateau, is described and illustrated. It is characterized by grayish green
non-ostiolate ascomata surrounded by a thick layer of hülle cells, membranaceous peridium, prototunicate asci, violet-brown,
lenticular ascospores which are ornamented by two stellate equatorial crests, capitate convex surfaces, and long filiform
appendages, and anAspergillus anamorph with biseriate conidiogenous cells. 相似文献
125.
Reduced toxicity and broad spectrum resistance to viral and fungal infection in transgenic plants expressing pokeweed antiviral protein II 总被引:3,自引:0,他引:3
Pokeweed antiviral protein II (PAPII), a 30 kDa protein isolated from leaves of Phytolacca americana, inhibits translation by catalytically removing a specific adenine residue from the large rRNA of the 60S subunit of eukaryotic ribosomes. The protein sequence of PAPII shows only 41% identity to PAP and PAP-S, two other antiviral proteins isolated from pokeweed. We isolated a cDNA corresponding to PAPII and introduced it into tobacco plants. PAPII expressed in transgenic tobacco was correctly processed to the mature form as in pokeweed and accumulated to at least 10-fold higher levels than wild-type PAP. We had previously observed a significant decrease in transformation frequency with PAP and recovered only two transgenic lines expressing 1–2 ng per mg protein. In contrast, eight different transgenic lines expressing up to 250 ng/mg PAPII were recovered, indicating that PAPII is less toxic than PAP. Two symptomless transgenic lines expressing PAPII were resistant to tobacco mosaic virus, potato virus X and the fungal pathogen Rhizoctonia solani. The level of viral and fungal resistance observed correlated well with the amount of PAPII protein accumulated. Pathogenesis-related protein PR1 was constitutively expressed in transgenic lines expressing PAPII. Although PR1 was constitutively expressed, no increase in salicylic acid levels was detected, indicating that PAPII may elicit a salicylic acid-independent signal transduction pathway. 相似文献
126.
127.
128.
Mycelium, oospores and zoospore cysts of Pythium spp. were fed to larvae of the fungus gnat Bradysia impatiens. The fungal structures were all ingested and provided a complete nutritional source for the insect's development from egg to adult. Mycelium seemed the major source of food as only empty fragments were found either in the digestive tract or in larval faeces. Oospores appeared intact and were viable both during passage through the tract and when expelled. Germination of oospores was normal. Most encysted zoospores also survived passage through the gut, although some appeared damaged. After transferring recently-fed larvae to a new food source, oospores were still detected in the digestive tract 48 h later. These results show that the larval stage of B. impatiens may serve as an important vector for Pythium spp. 相似文献
129.
David Mugisho Bugeme Markus Knapp Sunday Ekesi Adenirin Chabi‐Olaye Hamadi Iddi Boga Nguya Kalemba Maniania 《Insect Science》2015,22(1):121-128
The efficacy of aqueous and emulsifiable formulations of the fungus Metarhizium anisopliae isolate ICIPE78 was evaluated on the population density of Tetranychus urticae infesting common bean plants under screenhouse and field conditions. Synthetic acaricide abamectin was included as a check. Bean plants were artificially infested with T. urticae and allowed to multiply. Three treatments were applied in the screenhouse and 1 treatment in field trials. Mite density was recorded 2 d before spraying and weekly postspraying. The number of pods per plant, number of seeds per pod, and the dry weight of seeds per plant were recorded only in the screenhouse trials. In both screenhouse and field trials, fungal formulations applied at the concentration of 108 conidia/mL and the acaricide reduced the population density of mites as compared to the controls. There were significant differences in T. urticae population densities between the treatments at the various post‐spraying sampling dates. In the screenhouse, the mite densities were near zero from 3‐week postspraying in the treated leaves. At 4‐week postspraying, there were no more leaves in the untreated control (T1) and in the control water + Silwet‐L77 (T2). Fungal formulations were as effective as abamectin in reducing mite densities in both screenhouse and field experiments. There were significant differences in the production parameters during the 2 screenhouse trials, with fungal and abamectin treatments generally having the highest yield. Results of this study underline the potential of the M. anisopliae isolate ICIPE78 as an alternative to acaricides for T. urticae management. 相似文献
130.
《Fungal Ecology》2015
The pine weevil is one of the most important pest insects of conifer reforestation areas in Europe. Female pine weevils cover their eggs with chewed bark and feces (frass) resulting in avoidance behavior of feeding conspecifics towards egg laying sites. It has been suggested that microorganisms present in the frass may be responsible for producing deterrent compounds for the pine weevil. The fungi Ophiostoma canum, O. pluriannulatum, and yeast Debaryomyces hansenii were isolated from aseptically collected pine-weevil frass. The isolated fungi were cultured on weevil frass broth and their volatiles were collected by SPME and identified by GC–MS. D. hansenii produced methyl salicylate (MeS) as a major compound, whereas, in addition, O. canum and O. pluriannulatum produced 6-protoilludene. In a multi-choice lab bioassay, MeS strongly reduced pine weevil's attraction to the Pinus sylvestris volatiles. Thus, a fungal metabolite was found that strongly affects the pine weevil host-odor search. 相似文献