全文获取类型
收费全文 | 288篇 |
免费 | 23篇 |
专业分类
311篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 10篇 |
2012年 | 15篇 |
2011年 | 11篇 |
2010年 | 9篇 |
2009年 | 11篇 |
2008年 | 13篇 |
2007年 | 11篇 |
2006年 | 7篇 |
2005年 | 13篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1971年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有311条查询结果,搜索用时 15 毫秒
131.
Tissue distribution of ia antigens: Ia on spermatozoa,macrophages, and epidermal cells 总被引:2,自引:2,他引:0
Direct cytotoxic tests and absorption studies demonstrated thatI-region associated antigens (Ia) are not restricted to lymphocytes. Ia was found on spermatozoa, macrophages, and on epidermal cells, whereas Ia was absent from brain, liver, kidney, and fibroblasts. The possible biological meaning of these observations is discussed. 相似文献
132.
Mixed lymphocyte reaction (MLR) stimulation by purified T and B lymphocytes and thymocytes was studied. The MLR gene products involved were localized to theH-2 complex by the use of congenic mice differing atH-2, and to loci within theH-2 complex through the use of congenic mice bearing recombinant chromosome 17. Stimulation by T cells was investigated in detail. The role of small amounts of contaminating B lymphocytes, and that of backstimulation, was found to be of minor importance. T cells and thymocytes stimulated as well as or better than B cells in combinations differing in theI, S, and possibly parts of theD end, thus suggesting that these genetic regions control cell-surface products expressed on both T and B lymphocyte populations.Abbreviations used in this paper are MLR
mixed lymphocyte reaction
- GVHR
graft-versus-host reaction
- CML
cell-mediated lympholysis
- Thy-1
the gene for the T-cell antigens, synonymous with
- Thy-1.1
synonym for
AKR
- Thy-1.2
synonym for
C3H
- MHC
major histocompatibility complex
-
Ir genes
immune response genes linked to the MHC
- LPS
E. coli 055.35 lipopolysaccharide
For the genetic nomenclature of theH-2 complex (H-2K, H-2D, I, S, D regions,Ia, etc.) see Kleinet al. 1974, and Shreffleret al. 1974. 相似文献
133.
The capping of Ia antigens does not induce redistribution of Fc receptors (FcR) on B lymphocytes. This rules out the possibility of a unidirectional association between Ia and FcR such as has been reported to link Ig and FcR. Ia-capping was achieved with hapten-sandwich antibodies devoid of Fc regions: hapten-conjugated Fab anti-Ia followed by (Fab')2 anti-hapten antibody. Three different immune complex systems were used to label FcR. With fluorescent double labeling, Ia and FcR were readily distinguished. The independent labeling and surface mobility of Ia and FcR are considered in connection with reports of the inhibition of FcR by anti-Ia antibodies. 相似文献
134.
Floriano PN Christodoulides N Romanovicz D Bernard B Simmons GW Cavell M McDevitt JT 《Biosensors & bioelectronics》2005,20(10):2079-2088
We report here the adaptation of our electronic microchip technology towards the development of a new method for detecting and enumerating bacterial cells and spores. This new approach is based on the immuno-localization of bacterial spores captured on a membrane filter microchip placed within a flow cell. A combination of microfluidic, optical, and software components enables the integration of staining of the bacterial species with fully automated assays. The quantitation of the analyte signal is achieved through the measurement of a collective response or alternatively through the identification and counting of individual spores and particles. This new instrument displays outstanding analytical characteristics, and presents a limit of detection of approximately 500 spores when tested with Bacillus globigii (Bg), a commonly used simulant for Bacillus anthracis (Ba), with a total analysis time of only 5 min. Additionally, the system performed well when tested with real postal dust samples spiked with Bg in the presence of other common contaminants. This new approach is highly customizable towards a large number of relevant toxic chemicals, environmental factors, and analytes of relevance to clinical chemistry applications. 相似文献
135.
Li S Floriano PN Christodoulides N Fozdar DY Shao D Ali MF Dharshan P Mohanty S Neikirk D McDevitt JT Chen S 《Biosensors & bioelectronics》2005,21(4):574-580
This paper presents disposable protein analysis chips with single- or four-chamber-constructed from poly(dimethylsiloxane) (PDMS) and silicon. The chips are composed of a multilayer stack of PDMS layers that sandwich a silicon microchip. This inner silicon chip features an etched array of micro-cavities hosting polymeric beads. The sample is introduced into the fluid network through the top PDMS layer, where it is directed to the bead chamber. After reaction of the analyte with the probe beads, the signal generated on the beads is captured with a CCD camera, digitally processed, and analyzed. An established bead-based fluorescent assay for C-reactive protein (CRP) was used here to characterize these hybrid chips. The detection limit of the single-chamber protein chip was found to be 1 ng/ml. Additionally, using a back pressure compensation method, the signals from each chamber of the four-chamber chip were found to fall within 10% of each other. 相似文献
136.
McDevitt RE Malamas MS Manas ES Unwalla RJ Xu ZB Miller CP Harris HA 《Bioorganic & medicinal chemistry letters》2005,15(12):3137-3142
The syntheses of a series of 2-arylindene-1-ones as potent ligands of ERbeta and ERalpha are described. Several compounds exhibited high potency and moderate selectivity for the ERbeta receptor. X-ray and modeling studies were used to understand ligand binding orientation and observed affinity. 相似文献
137.
Timothy J. Abram Curtis R. Pickering Alexander K. Lang Nancy E. Bass Rameez Raja Cynthia Meena Amin M. Alousi Jeffrey N. Myers John T. McDevitt Ann M. Gillenwater Nadarajah Vigneswaran 《Translational oncology》2018,11(2):477-486
Fanconi anemia (FA) is a hereditary genomic instability disorder with a predisposition to leukemia and oral squamous cell carcinomas (OSCCs). Hematopoietic stem cell transplantation (HSCT) facilitates cure of bone marrow failure and leukemia and thus extends life expectancy in FA patients; however, survival of hematologic malignancies increases the risk of OSCC in these patients. We developed a “cytology-on-a-chip” (COC)–based brush biopsy assay for monitoring patients with oral potentially malignant disorders (OPMDs). Using this COC assay, we measured and correlated the cellular morphometry and Minichromosome Maintenance Complex Component 2 (MCM2) expression levels in brush biopsy samples of FA patients’ OPMD with clinical risk indicators such as loss of autofluorescence (LOF), HSCT status, and mutational profiles identified by next-generation sequencing. Statistically significant differences were found in several cytology measurements based on high-risk indicators such as LOF-positive and HSCT-positive status, including greater variation in cell area and chromatin distribution, higher MCM2 expression levels, and greater numbers of white blood cells and cells with enlarged nuclei. Higher OPMD risk scores were associated with differences in the frequency of nuclear aberrations and differed based on LOF and HSCT statuses. We identified mutation of FAT1 gene in five and NOTCH-2 and TP53 genes in two cases of FA patients’ OPMD. The high-risk OPMD of a non-FA patient harbored FAT1, CASP8, and TP63 mutations. Use of COC assay in combination with visualization of LOF holds promise for the early diagnosis of high-risk OPMD. These minimally invasive diagnostic tools are valuable for long-term surveillance of OSCC in FA patients and avoidance of unwarranted scalpel biopsies. 相似文献
138.
Recently, a group of diplomonads has been found to use a genetic code in
which TAA and TAG encode glutamine rather than termination. To survey the
distribution of this characteristic in diplomonads, we sought to identify
TAA and TAG codons at positions where glutamine is expected in genes for
alpha-tubulin, elongation factor-1 alpha, and the gamma subunit of
eukaryotic translation initiation factor-2. These sequences show that the
variant genetic code is utilized by almost all diplomonads, with the genus
Giardia alone using the universal genetic code. Comparative phylogenetic
analysis reveals that the switch to this genetic code took place very early
in the evolution of diplomonads and was likely a single event. Termination
signals and downstream untranslated regions were also cloned from three
Hexamita genes. In all three of these genes, the predicted TGA termination
codon was found at the expected position. Interestingly, the untranslated
regions of these genes are high in AT. This is incongruent with the coding
regions, which are comparatively GC-rich.
相似文献
139.
Sequential alterations in the ultrastructure of blood platelets observed during the clotting of human platelet-rich plasma are described, with emphasis on disintegration of the platelet. As the clotting reaction proceeds, aliquots of citrated and recalcified citrated plasma are fixed by adding buffered OsO4. After recalcification a lag period of about 10 minutes is followed by an interval of rapidly occurring changes which include reorientation of cytoplasmic contents, progressive central degeneration, and disruption of the platelet limiting membrane. Shortly thereafter vesicular platelet remains are seen at the peripheries of loosely arranged and widely spaced masses of granular material. As clot retraction proceeds, these masses gradually come closer together, become more and more compact, and finally disappear. At the same time the vesicles undergo progressive disintegration until at the end of the experiment, 2 hours after recalcification, only a few are found randomly distributed in a dense clot. The significance of progressive disintegration and the origin of the vesicles observed in the later stages of the experiment are discussed in relation to clot formation and clot retraction. 相似文献
140.
Denise B. O’Meara Allan D. McDevitt David O’Neill Andrew P. Harrington Peter Turner William Carr Michael Desmond Colin Lawton Ferdia Marnell Sarah Rubalcava Emma Sheehy David P. Sleeman David Tosh Catherine Waters Catherine O’Reilly 《Acta theriologica》2018,63(2):173-184
The Eurasian red squirrel’s (Sciurus vulgaris) history in Ireland is largely unknown, but the original population is thought to have been driven to extinction by humans in the seventeenth century, and multiple records exist for its subsequent reintroduction in the nineteenth century. However, it is currently unknown how these reintroductions affect the red squirrel population today, or may do so in the future. In this study, we report on the development of a DNA toolkit for the non-invasive genetic study of the red squirrel. Non-invasively collected red squirrel samples were combined with other samples collected throughout Ireland and previously published mitochondrial DNA (mtDNA) data from Ireland, Great Britain and Continental Europe to give an insight into population genetics and historical introductions of the red squirrel in Ireland. Our findings demonstrate that the Irish red squirrel population is on a national scale quite genetically diverse, but at a local level contains relatively low levels of genetic diversity, and there is also evidence of genetic structure. This is likely an artefact of the introduction of a small number of genetically similar animals to specific sites. A lack of continuous woodland cover in Ireland has prevented further mixing with animals of different origins that may have been introduced even to neighbouring sites. Consequently, some of these genetically isolated populations are or may in the future be at risk of extinction. The Irish red squirrel population contains mtDNA haplotypes of both a British and Continental European origin, the former of which are now extinct or simply not recorded in contemporary Great Britain. The Irish population is therefore important in terms of red squirrel conservation not only in Ireland, but also for Great Britain, and should be appropriately managed. 相似文献