全文获取类型
收费全文 | 123篇 |
免费 | 5篇 |
专业分类
128篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有128条查询结果,搜索用时 0 毫秒
31.
32.
The heat shock protein 90 (hsp90) gene sequence is known to be highly conserved across the species barrier. A PCR-based method was thus utilised in an attempt to sequence the Candida tropicalis hsp90 gene. Primers for PCR were designed from conserved regions of the gene, which were identified by comparing the Saccharomyces cerevisiae and Candida albicans hsp90 gene sequences. Different sets of primers were designed to amplify and obtain overlapping DNA sequences of the C tropicalis gene. PCR was carried out on genomic DNA of Candidca tropicalis and the PCR products were cloned into suitable vector molecules for sequencing. In this way, a 2,070-basepair sequence of the C. tropicalis hsp90 gene was obtained. The PCR-based approach proved to be an easier method of obtain the sequence of a highly conserved gene, as compared to more conventional methods. 相似文献
33.
Outbreak of coagulase negative staphylococcus highly resistant to ciprofloxacin in a leukaemia unit.
B. A. Oppenheim J. W. Hartley W. Lee J. P. Burnie 《BMJ (Clinical research ed.)》1989,299(6694):294-297
OBJECTIVE--To define an outbreak of bacteraemia due to coagulase negative staphylococci highly resistant to ciprofloxacin in a leukaemia unit, investigate the source and mode of spread of the outbreak strain, and assess control measures. DESIGN--The outbreak strain was characterised by five different typing methods. Surveillance of patients, staff, and environment was carried out during the outbreak and five months after control measures were introduced. SETTING--A unit with 10 beds for adults with leukaemia and patients receiving bone marrow transplants. The outbreak occurred during a trial of ciprofloxacin for empirical treatment of neutropenic fevers. INTERVENTIONS--Ciprofloxacin was withdrawn from use in the unit and daily bathing with chlorhexidine gluconate solution started. Main outcome measure--The absence of bacteraemia due to the outbreak strain for five months after control measures. RESULTS--During the study 49 patients developed 21 episodes of bacteraemia due to the outbreak strain, which was ciprofloxacin resistant (minimum inhibitory concentration greater than or equal to 128 mg/l), susceptible to phage 155 A9C, and SII biotype and had characteristic immunoblot and DNA fingerprint features. There was a high amount of colonisation of patients but not staff with this strain, which was also wide spread in the environment. The control measures led to rapid resolution of the outbreak and disappearance of the strain from the unit. CONCLUSIONS--In areas where coagulase negative staphylococcal infections are common doctors must be aware of the possibility of cross infection with single strain, and the availability of more discriminatory methods of typing will facilitate the identification and control of such episodes. 相似文献
34.
Three experiments were carried out to examine the consequences of concurrent infections with Ascaridia galli and Escherichia coli in chickens raised for table egg production. Characteristic pathological lesions including airsacculitis, peritonitis and/or polyserositis were seen in all groups infected with E. coli. Furthermore, a trend for increased mortality rates was observed in groups infected with both organisms which, however, could not be confirmed statistically. The mean worm burden was significantly lower in combined infection groups compared to groups infected only with A. galli. It was also shown that combined infections of E. coli and A. galli had an added significant negative impact on weight gain. 相似文献
35.
Delphine Depoix Sara Rute Marques David JP Ferguson Soraya Chaouch Thomas Duguet Robert E Sinden Philippe Grellier Linda Kohl 《Cellular microbiology》2020,22(3)
Sexual development is an essential phase in the Plasmodium life cycle, where male gametogenesis is an unusual and extraordinarily rapid process. It produces 8 haploid motile microgametes, from a microgametocyte within 15 minutes. Its unique achievement lies in linking the assembly of 8 axonemes in the cytoplasm to the three rounds of intranuclear genome replication, forming motile microgametes, which are expelled in a process called exflagellation. Surprisingly little is known about the actors involved in these processes. We are interested in kinesins, molecular motors that could play potential roles in male gametogenesis. We have undertaken a functional characterization in Plasmodium berghei of kinesin‐8B (PbKIN8B) expressed specifically in male gametocytes and gametes. By generating Pbkin8B‐gfp parasites, we show that PbKIN8B is specifically expressed during male gametogenesis and is associated with the axoneme. We created a ΔPbkin8B knockout cell line and analysed the consequences of the absence of PbKIN8B on male gametogenesis. We show that the ability to produce sexually differentiated gametocytes is not affected in ΔPbkin8B parasites and that the 3 rounds of genome replication occur normally. Nevertheless, the development to free motile microgametes is halted and the life cycle is interrupted in vivo. Ultrastructural analysis revealed that intranuclear mitoses are unaffected whereas cytoplasmic microtubules, although assembled in doublets and elongated, fail to assemble in the normal axonemal ‘9+2' structure and become motile. Absence of a functional axoneme prevented microgamete assembly and release from the microgametocyte, severely reducing infection of the mosquito vector. This is the first functional study of a kinesin involved in male gametogenesis. These results reveal a previously unknown role for PbKIN8B in male gametogenesis, providing new insights into Plasmodium flagellar formation. 相似文献
36.
Background
Comparative genomic data among organisms allow the reconstruction of their phylogenies and evolutionary time scales. Molecular timings have been recently used to suggest that environmental global change have shaped the evolutionary history of diverse terrestrial organisms. Living xenarthrans (armadillos, anteaters and sloths) constitute an ideal model for studying the influence of past environmental changes on species diversification. Indeed, extant xenarthran species are relicts from an evolutionary radiation enhanced by their isolation in South America during the Tertiary era, a period for which major climate variations and tectonic events are relatively well documented. 相似文献37.
GMDD: a database of GMO detection methods 总被引:1,自引:0,他引:1
Wei Dong Litao Yang Kailin Shen Banghyun Kim Gijs A Kleter Hans JP Marvin Rong Guo Wanqi Liang Dabing Zhang 《BMC bioinformatics》2008,9(1):260
Background
Since more than one hundred events of genetically modified organisms (GMOs) have been developed and approved for commercialization in global area, the GMO analysis methods are essential for the enforcement of GMO labelling regulations. Protein and nucleic acid-based detection techniques have been developed and utilized for GMOs identification and quantification. However, the information for harmonization and standardization of GMO analysis methods at global level is needed. 相似文献38.
The demonstration that interleukin 2 (IL-2) is a lectin specific for
oligomannosides allows to understand a new function for this cytokine: as a
bifunctional molecule when bound to its receptor ss, IL-2 associates the
latter which the CD3/TCR complex, interacting with oligosaccharides of CD3
through its carbohydrate-recognition domain (Zanetta et al. , 1996,
Biochem. J., 318, 49-53). This induces the tyrosine phosphorylation of the
IL-2R beta by ++p56(lck) , the first step of the IL-2-dependent signaling.
Since this specific association is disrupted in vitro by oligomannosides
with five and six mannose residues, we made the hypothesis that pathogenic
cells or microorganisms could bind IL-2, consequently disturbing the IL-2-
dependent response. This study shows that the pathogenic yeast Candida
albicans (in contrast with nonpathogenic yeasts) binds high amounts of IL-2
as did cancer cells. In contrast with cancer cells, yeasts do not bind the
Man6GlcNAc2-specific lectin CSL, an endogenous "amplifier of activation
signals" (Zanetta et al. , 1995, Biochem. J., 311, 629-636).
相似文献
39.
40.