全文获取类型
收费全文 | 82篇 |
免费 | 12篇 |
出版年
2017年 | 2篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 6篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1984年 | 3篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1968年 | 3篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1959年 | 1篇 |
1951年 | 1篇 |
1949年 | 1篇 |
1948年 | 1篇 |
1947年 | 1篇 |
1945年 | 1篇 |
1944年 | 1篇 |
1942年 | 1篇 |
排序方式: 共有94条查询结果,搜索用时 15 毫秒
61.
Claudia Schleger Rosario Heck Fataneh Niketeghad Peter Schirmacher Svetlana Radaeva Franz Oesch Hans Peter Dienes Peter Bannasch Pablo Steinberg 《Experimental cell research》1997,236(2):418
In the present study the establishment and characterization of a nontumorigenic liver epithelial cell line (HACL-1) derived from a human hepatocellular adenoma is described. The HACL-1 cells have a finite life span (i.e., they proliferate for a period of 2 months and then senesce), show cell–cell contact inhibition, do not grow in soft agar, are not tumorigenic when injected in nude mice, and possess a normal diploid karyotype. The cultured cells resemble hepatocytes, but exhibit some features of dedifferentiation. At the ultrastructural level the cells are endowed with round or oval nuclei, abundant cytoplasmic organelles, and varying amounts of glycogen. The rough endoplasmic reticulum is disorganized, while peroxisomes and matrix granules within mitochondria are lacking. HACL-1 cells are cytokeratin 18-positive as well as (transiently) albumin- and α-fetoprotein-positive, but do not express cytokeratin 19. Furthermore, no mutations were observed in exons 5–8 of the tumor suppressor genep53.Taken together these results show that HACL-1 cells are nontumorigenic proliferating liver epithelial cells, which might prove to be of great value in future studies on diverse aspects of human liver cell biology and carcinogenesis. 相似文献
62.
63.
Three visual search experiments examined whether motion is coded as two separate features, speed and direction. Increasing the heterogeneity of the directions in which stimuli moved disrupted detection of a target defined by speed (fast among medium and slow nontargets), suggesting that speed is coded integrally with direction. However, heterogeneity in speed did not disrupt detection of a target moving in a particular direction among nontargets with different directions. This suggests that direction is coded independently of speed. The apparent paradox raised by these contrasting conclusions is consistent with neurophysiological and computational models of motion-detection, which suggest that low-levels of the visual system contain direction-detectors insensitive to speed, while speed is coded at higher levels by detectors which are also sensitive to direction. Evidence consistent with the existence of the latter conjunction detectors was obtained in a final experiment which found search for a conjunction of speed and direction to be parallel. 相似文献
64.
Regulation of perforin activation and pre‐synaptic toxicity through C‐terminal glycosylation
下载免费PDF全文
![点击此处可从《EMBO reports》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Amelia J Brennan Omer Gilan Mark A Dawson James C Whisstock Ruby HP Law Joseph A Trapani Ilia Voskoboinik 《EMBO reports》2017,18(10):1775-1785
Perforin is a highly cytotoxic pore‐forming protein essential for immune surveillance by cytotoxic lymphocytes. Prior to delivery to target cells by exocytosis, perforin is stored in acidic secretory granules where it remains functionally inert. However, how cytotoxic lymphocytes remain protected from their own perforin prior to its export to secretory granules, particularly in the Ca2+‐rich endoplasmic reticulum, remains unknown. Here, we show that N‐linked glycosylation of the perforin C‐terminus at Asn549 within the endoplasmic reticulum inhibits oligomerisation of perforin monomers and thus protects the host cell from premature pore formation. Subsequent removal of this glycan occurs through proteolytic processing of the C‐terminus within secretory granules and is imperative for perforin activation prior to secretion. Despite evolutionary conservation of the C‐terminus, we found that processing is carried out by multiple proteases, which we attribute to the unstructured and exposed nature of the region. In sum, our studies reveal a post‐translational regulatory mechanism essential for maintaining perforin in an inactive state until its secretion from the inhibitory acidic environment of the secretory granule. 相似文献
65.
ERRATUM: Wright LE and Schwarcz HP (1998) Stable Carbon and Oxygen Isotopes in Human Tooth Enamel: Identifying Breastfeeding and Weaning in Prehistory. Am. J. Phys. Anthropol. 106: 1–18. Isotopic ratios were incorrectly printed as percentages (%) rather than units permil (‰). Wherever “breast feeding” and “breast fed” occur, the words should be combined into “breastfeeding” and “breastfed” respectively. The correct information on isotopic ratios is the following: p. 1, Abstract: all % signs should be “‰”; p. 2, column two, last line: “… δ13C values1, have been …”; p. 2, Footnote 1 should read: “Isotope ratios of carbon and oxygen are expressed in δ notation as follows, δ = [(Rsample/Rstandard) − 1] × 1000, where R = 13C/12C for δ13C, and R = 18O/16O for δ18O, and are in units permil, ‰.”; p. 3, column two: all % signs should be “‰”, except for the 23rd line from the bottom, which reads: “… provided 95% of water intake by all infants …”; p. 5: all % signs should be “‰”; p. 6, column one: 8th and 9th line from bottom should be “… mean deviations were 0.029‰ for δ13C and 0.024‰ for δ18O …”; p. 6, column one: 2nd line from bottom should be “… only 0.208‰ for δ13C and only 0.091‰ for δ18O …”; p. 6, column two: top line: “… of 0.5‰ in δ13C and 0.2‰ in δ18O …”; p. 8, 9 and 10: all % signs should be “‰”; p. 11, column two: 7th line from top: “… the lipids are 4-6‰ lighter …”; p. 12, 13 and 14: all % signs should be “‰.” 相似文献
66.
67.
Morphology and Reproductive Processes of the L Forms of Bacteria I. Streptococci and Straphylocci
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Louis Dienes 《Journal of bacteriology》1967,93(2):693-702
The production of L forms from cocci, the conditions necessary for their multiplication, and their morphology have been studied for several years. In each strain studied, only a few organisms produced L forms. Transplants from these grew poorly at first, and growth on agar and in broth became abundant only after long cultivation. Multiplication in the form of small granules was observed only when the organisms were embedded in agar and occasionally in coagulated blood serum. On the surface of hard agar, the organisms increased in size but did not multiply. Abundant growth developed on membrane filters of appropriate size, extending into the filters as branching irregular masses. On gelatin, on most samples of coagulated serum, and on silica gel, the organisms grew to a very large size, and occasionally colonies developed by multiplication of large bodies. This multiplication occurred by irregular enlargement and separation into fragments. Growth in broth and in semisolid agar also occurred by multiplication of large bodies, but, in addition, the development of viable granules was observed inside the large bodies in broth culture. After the L forms began to grow abundantly, their nutritional requirements were simple; they no longer required animal serum. Their ability to multiply and their morphological characteristics depended to a large extent on the physical properties of the environment. 相似文献
68.
Abeba Tesfaye Judith Stift Dragan Maric Qingwen Cui Hans-Peter Dienes Stephen M. Feinstone 《PloS one》2013,8(10)
While the chimpanzee remains the only animal that closely models human hepatitis C virus (HCV) infection, transgenic and immunodeficient mice in which human liver can be engrafted serve as a partial solution to the need for a small animal model for HCV infection. The established system that was based on mice carrying a transgene for urokinase-type plasminogen activator (uPA) gene under the control of the human albumin promoter has proved to be useful for studies of virus infectivity and for testing antiviral drug agents. However, the current Alb-uPA transgenic model with a humanized liver has practical limitations due to the inability to maintain non-engrafted mice as dizygotes for the transgene, poor engraftment of hemizygotes, high neonatal and experimental death rates of dizygous mice and a very short time window for hepatocyte engraftment. To improve the model, we crossed transgenic mice carrying the uPA gene driven by the major urinary protein promoter onto a SCID/Beige background (MUP-uPA SCID/Bg). These transgenic mice are healthy relative to Alb-uPA mice and provide a long window from about age 4 to 12 months for engraftment with human hepatocytes and infection with hepatitis C or hepatitis B (HBV) viruses. We have demonstrated engraftment of human hepatocytes by immunohistochemistry staining for human albumin (30-80% engraftment) and observed a correlation between the number of human hepatocytes inoculated and the level of the concentration of human albumin in the serum. We have shown that these mice support the replication of both HBV and all six major HCV genotypes. Using HBV and HCV inocula that had been previously tittered in chimpanzees, we showed that the mice had approximately the same sensitivity for infection as chimpanzees. These mice should be useful for isolating non-cell culture adapted viruses as well as testing of antiviral drugs, antibody neutralization studies and examination of phenotypic changes in viral mutants. 相似文献
69.
The Isolation of L Type Cultures from Bacteroides with the Aid of Penicillin and Their Reversion into the Usual Bacilli 总被引:15,自引:5,他引:10
Dienes L 《Journal of bacteriology》1948,56(4):445-456
70.
P Schirmacher M W?rsd?rfer K Lübbe D Falke W Thoenes H P Dienes 《Virchows Archiv. B, Cell pathology including molecular pathology》1989,56(6):351-361
In order to characterize better the morphology and immune response in acute necrotizing HSV infection, murine HSV hepatitis was examined. BALB/c mice were inoculated intraperitoneally with 10(6) plaque-forming units (PFU) of HSV-1 (Lenette) and HSV-2 (D316). In both groups half the animals were pretreated with silica particles to block macrophage function. Up to 6 days after infection four mice from each group were sacrificed at daily intervals and the livers were examined by light and electron microscopy, immunohistology, in situ hybridization, combined immunohistology/in situ hybridization and titration of viral PFU. HSV-2 infected mice developed severe necrotizing hepatitis with persistence of HSV in the liver tissue until the end of the study. HSV-1 infected mice rapidly eliminated the virus and revealed only small necrotic foci. Early phase alterations and necrotic phase lesions were distinguished and characterized and morphologic evidence of a direct cytopathic effect of HSV was detected. A specific immune reaction in late stages appeared to be mediated by T4-positive T-lymphocytes. In situ hybridization and immunohistochemistry showed a close correlation with virus titration and were valuable in characterizing early phases and in the assessment of prognosis and differential diagnosis. 相似文献