全文获取类型
收费全文 | 997篇 |
免费 | 63篇 |
国内免费 | 1篇 |
专业分类
1061篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 19篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 11篇 |
2017年 | 15篇 |
2016年 | 21篇 |
2015年 | 34篇 |
2014年 | 34篇 |
2013年 | 54篇 |
2012年 | 61篇 |
2011年 | 77篇 |
2010年 | 45篇 |
2009年 | 52篇 |
2008年 | 65篇 |
2007年 | 77篇 |
2006年 | 92篇 |
2005年 | 55篇 |
2004年 | 74篇 |
2003年 | 48篇 |
2002年 | 45篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有1061条查询结果,搜索用时 0 毫秒
1.
Jozef Anné Patrick Verheyen Guido Volckaert Hendrik Eyssen 《Molecular & general genetics : MGG》1985,200(3):506-507
Summary A physical map of the actinophage VWB has been constructed using the restriction endonucleases BglII, ClaI, EcoRI, EcoRV, HindIII, KpnI and SphI. Phage VWB, genome size 47.3 kb, propagates on Streptomyces venezuelae, and it can also lysogenise this species. The three BglII-generated fragments of VWB DNA were cloned in pBR322, and subsequently mapped. In this manner the restriction map of the VWB phage genome was constructed.Abbreviations
dam
DNA adenine methylase activity
- kb
kilobase pairs
- ::
novel joint 相似文献
2.
Ann Depicker Lieve Herman Anni Jacobs Jozef Schell Marc Van Montagu 《Molecular & general genetics : MGG》1985,201(3):477-484
Summary We investigated whether the efficiency of transformation of plant cells by Agrobacterium tumefaciens during cocultivation is limited by the properties of the plant cells or by the infecting bacteria.Therefore, tobacco protoplasts were infected by cocultivation with two different agrobacteria strains carrying Ti plasmids with distinguishable T-DNAs. These T-DNAs cotransform plant cells at a frequency equal to the product of their independent transformation frequencies, which indicates that all plant cells are equally competent. On the other hand, when these T-DNAs are located on the same Ti plasmid vector within one bacterial strain, the cotransformation frequency is significantly higher than the product of the single transformation frequencies. We interpret these results to indicate that transformation is limited more by the establishment of effective bacteria/plant cell interaction than by (i) the process of DNA integration and (ii) by the number of plant cells capable of being transformed by Agrobacterium. We found that most plant cells are transformed by only one or a few agrobacteria. Analysis of the number of T-DNA copies in these clonally transformed lines indicates amplification of the original, infecting T-region copy. 相似文献
3.
4.
5.
6.
7.
8.
Jozef B. Woelke Tibor Bukovinszky Martinus E. Huigens 《Biocontrol Science and Technology》2017,27(6):769-780
Parasitoid wasps of the genus Trichogramma are used worldwide as biological control agents against lepidopteran pests. Trichogramma wasps develop inside eggs of a wide range of host species, most of them moths. They are generally considered as diurnal insects. Here, we investigated whether Trichogramma wasps can also successfully parasitise host eggs at night under controlled laboratory conditions. Eggs of the moth Ephestia kuehniella were offered under dark conditions (scotophase) to females of Trichogramma brassicae and Trichogramma evanescens either from 9:00 PM to 9:00 AM or from 11:00 AM to 5:00 PM at four different temperatures (5°C, 10°C, 15°C and 20°C). Both species are known to parasitise E. kuehniella eggs in the photophase during daytime. The results show that T. brassicae did not parasitise eggs in the scotophase at night and only very few in the artificially induced scotophase during daytime from 10°C to 20°C. In contrast, T. evanescens parasitised more eggs in the dark both at night and artificially induced scotophase during daytime. Parasitism in the scotophase already started at 5°C, with more eggs being parasitised and more offspring being produced at higher temperatures. T. evanescens displayed higher parasitism activity in the induced scotophase during daytime than in the scotophase at night. The present study suggests that Trichogramma are capable of successfully parasitising host eggs at night, even at low temperatures, but that nocturnal activity with respect to parasitism varies between wasp species. 相似文献
9.
Ribosomal RNA sequences (361 or 362 bp) of the second internal transcribed spacer 2 (ITS-2) and a portion of mitochondrial cox1 (423 bp) for Fasciola spp. obtained from specimens collected in indigenous and hybrid goats and sheep in Vietnam were characterized for genotypic status and hybridization/introgression. Alignment of 48 ITS-2 sequences (also those from goats and sheep in this study) indicates that F. gigantica and F. hepatica differ typically from each other at seven sites whereas one of these is a distinguishing deletion (T) at the 327th position in F. gigantica relative to F. hepatica. The isolates from the mountainous goats in the North of Vietnam (Yen Bai province) showed the ITS-2 composition relatively identical to that of F. hepatica. The ITS-2 sequences from populations of Fasciola isolates in goats had probably experienced introgression/hybridization as reported previously in other ruminants and humans. All Vietnamese goat-of-origin specimens had high pairwise percentage of mitochondrial cox1 sequences to F. gigantica (97-100%), and very low identity to F. hepatica (91-93%), suggesting their maternal linkage to be traced to F. gigantica. The presence of hybrid and/or introgressed populations of liver flukes bearing genetic material from both F. hepatica and F. gigantica in the goats/sheep in Vietnam, regardless of indigenous or imported hosts, appears to be the first demonstration from a tropical country. 相似文献
10.
Maize callus cells possess numerous protein bodies which develop as sub-compartments of the endoplasmic reticulum. We localized
maize calreticulin mRNAs and protein in maize callus cells using in situ hybridization and immunocytochemistry. Calreticulin
mRNAs were selectively targeted to the endoplasmic reticulum (ER) subdomains surrounding protein bodies. Profilin mRNAs, used
as a positive control for in situ hybridization experiments, showed distinct and rather diffuse localization pattern. Using
both, immunofluorescence and immunogold electron microscopy localization techniques, calreticulin was found to be enriched
around and within protein bodies in maize callus storage cells. As a positive control for reticuloplasmins, HDEL antibody
revealed labelling of protein bodies and of the nuclear envelope. The identity of protein bodies was confirmed by specific
binding of an α zein antibody. These data suggest that calreticulin mRNA is targeted towards protein body forming subdomains
of the ER, and that calreticulin is localized and enriched in these protein bodies. The possibility that calreticulin plays
an important role in zein retention within the ER and/or its assembly and packaging into protein bodies during protein body
biogenesis in maize callus is discussed. 相似文献