全文获取类型
收费全文 | 244篇 |
免费 | 33篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 14篇 |
2015年 | 14篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 15篇 |
2011年 | 16篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 13篇 |
2007年 | 8篇 |
2006年 | 10篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1994年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1971年 | 1篇 |
1969年 | 2篇 |
1964年 | 1篇 |
1962年 | 2篇 |
1960年 | 1篇 |
排序方式: 共有277条查询结果,搜索用时 687 毫秒
261.
H. J. Eysenck Mollie Tarrant Myra Woolf L. England 《BMJ (Clinical research ed.)》1960,1(5184):1456-1460
262.
Myra Sellinger Weihong Xu Anita Pathil Wolfgang Stremmel Walee Chamulitrat 《Experimental biology and medicine (Maywood, N.J.)》2015,240(2):252-260
An increase of toxic bile acids such as glycochenodeoxycholic acid occurs during warm ischemia reperfusion causing cholestasis and damage in hepatocytes and intrahepatic biliary epithelial cells. We aim to test antiapoptosis effects of ursodeoxycholyl lysophosphatidylethanolamide under cholestatic induction by glycochenodeoxycholic acid treatment of mouse hepatocytes and hypoxia induction by cobalt chloride treatment of intrahepatic biliary epithelial cancer Mz-ChA-1cell line. Such treatments caused marked increases in apoptosis as evidenced by activation of caspase 3, caspase 8 and poly (ADP-ribose) polymerase-1. Co-treatment with ursodeoxycholyl lysophosphatidylethanolamide significantly inhibited these increases. Interestingly, ursodeoxycholyl lysophosphatidylethanolamide was able to increase expression of antiapoptotic cellular FLICE-inhibitory protein in both cell types. Ursodeoxycholyl lysophosphatidylethanolamide also prevented the decreases of myeloid cell leukemia sequence-1 protein in both experimental systems, and this protection was due to ursodeoxycholyl lysophosphatidylethanolamide’s ability to inhibit ubiquitination-mediated degradation of myeloid cell leukemia sequence-1, and to increase the phosphorylation of GSK-3β. In addition, ursodeoxycholyl lysophosphatidylethanolamide was able to prevent the decreased expression of another antiapoptotic cellular inhibitor of apoptosis 2 in cobalt chloride-treated Mz-ChA-1 cells. Hence, ursodeoxycholyl lysophosphatidylethanolamide mediated cytoprotection against apoptosis during toxic bile-acid and ischemic stresses by a mechanism involving accumulation of cellular FLICE-inhibitory protein, myeloid cell leukemia sequence-1 and cellular inhibitor of apoptosis 2 proteins. Ursodeoxycholyl lysophosphatidylethanolamide may thus be used as an agent to prevent hepatic ischemia reperfusion. 相似文献
263.
Myra J. Shulman 《Environmental Biology of Fishes》1985,13(2):81-92
Synopsis Observations were made on intra- and interspecific aggressive interactions among the fishes living in the rubble/sand coral reef habitat in St. Croix, U. S. Virgin Islands. Four species (beaugregory — Stegastes leucostictus; ocean surgeonfish — Acanthurus bahianus; doctor fish — A. chirurgus; common squirrelfish — Holocentrus rufus) which sheltered in holes on the reef all actively defended one to several shelter sites at dusk. Short-term shelter side fidelity was observed in three of these four species. Agonistic interactions over both food and shelter occurred during the daytime but much less frequently than agonistic interactions over shelter at dusk. Dominance in intraspecific aggression was determined almost completely by the relative sizes of the individuals involved, with the larger individuals dominating in 95–98% of all encounters. A similar, but less strong, relationship between size and dominance existed for interactions between closely related species. For aggressive encounters between unrelated species, however, both relative sizes and species identity determined the outcome. Species, both diurnal and nocturnal, which strongly defend several shelter sites may have a strong and disproportionate impact on the sheltering behavior of other fishes. Intraspecific and interspecific defense of shelter sites may determine the patterns of mortality that result from predation, thereby influencing population abundances and assemblage composition. 相似文献
264.
Crustecdysone, the hormone responsible for onset and regulation of the molt cycle in Crustacea, causes an increase in ionic coupling of cells of the hepatopancreas concomitant with the events of the molt. Hepatopancreatic tissue incubated for up to 4 hr in modified Eagle Basal Medium containing crustecdysone, exhibited an approximate 29% decrease in intercellular resistance as compared with tissue incubated in control medium. This represents a 29% increase in ionic coupling between hepatopancreatocytes following treatment with crustecdysone. Examination of platinum replicas of freeze-fractured, crustecdysone-treated hepatocyte plasma membrane revealed that most of the gap junction plaques were round with tightly packed intramembrane particles; a condition indicative of highly coupled cells. Similar preparations of control plasmalemmae demonstrated many gap junction plaques which were round or irregular in shape with very loosely packed particles and were indicative of uncoupled junctions. Results of this study are identical to those from a previous investigation of the electrophysiology and freeze-fracture morphology of hepatopancreatocytes during the molt cycle (McVicar and Shivers, 1984), and are thus presumed to reflect a crustecdysone-controlled increase in cell communications in vivo. 相似文献
265.
266.
John A. Wijsman Richard R. Shivers 《In vitro cellular & developmental biology. Animal》1998,34(10):777-784
Summary Studies of brain microvessel endothelial cell physiology and blood-brain barrier properties are often hampered by the requirement
of repeatedly producing and characterizing primary endothelial cell cultures. The use of viral oncogenes to produce several
immortalized brain microvessel cell lines has been reported. The resulting cell lines express many properties of the blood-brain
barrier phenotype but do not completely mimic primary endothelial cells in culture. As immortalized brain microvessel endothelial
cell lines have not yet been produced from mice, we transformed mouse brain endothelial cells with the adenovirus E1A gene
using a retroviral vector (DOL). Eight of 11 clones produced exhibited an endothelial-like cobblestone morphology and were
characterized as endothelial with a panel of antibodies, lectins, and ultrastructural criteria. These cells are endothelial
in origin and share ultrastructural features with primary cultures of endothelial cells. Examination of freeze fracture and
transmission electron micrographs show adherens junctions exist between the transformed cells, and culture in astrocyte-conditioned
medium induces the formation of gap junctions. This is one indication that responses to astrocyte-derived factors are retained
by the transformed cell lines. 相似文献
267.
The New York Bight possesses a diverse assemblage of phytoplanktonwhere seasonal periods of high growth are dominated by several,chain-forming diatoms and a pico-nanoplankton component Thecomposition is similar to other regions of the northeasternshelf, producing late winter-early spring and fall maxima. 相似文献
268.
David L. Williamson David I. Blaustein Rhea J. C. Levine Myra J. Elfvin 《Current microbiology》1979,2(3):143-145
An antiserum made against sodium dodecyl sulfate-denatured actin from invertebrates and coupled to horseradish peroxidase
specifically stains the wall-free prokaryoteSpiroplasma citri. The results of experiments with spiroplasmas reported here, coupled with the report of the extraction from them of an actin-like
protein, suggest that these highly motile organisms possess an actin-like mediated mechanism of motility. 相似文献
269.
270.
Lefke P. Karaviti Arlene B. Mercado Myra B. Mercado Phyllis W. Speiser Mimi Buegeleisen Christopher Crawford Lida Antonian Perrin C. White Maria I. New 《The Journal of steroid biochemistry and molecular biology》1992,41(3-8):445-451
The most common enzymatic defect of steroid synthesis is adrenal steroid 21-hydroxylase deficiency. Inhibited formation of cortisol causes increased pituitary release of ACTH, driving the adrenal cortex to overproduce androgens, whose synthesis does not involve the 21-hydroxylase enzyme. This hormonal setting is established in the embryonic period and affects development of genetic females, misdirecting differentiation of the external genitalia toward male type. At birth, the genitalia are visibly ambiguous (enlarged clitoris, fused labia) or in some cases even male in appearance {phallus with urethral opening, rugated scrotal sac), leading to wrong sex assignment. Adrenal steroid 21-hydroxylase deficiency is the most common basis of female pseudohermaphroditism. These females, however, have normal fertility and potential for gestation (gonads are functional and the internal duct-derived structures are well-formed), thus the sex of rearing should always be female. Management is by life-long hormonal (glucocorticoid) replacement, with surgical correction of the genital ambiguity. Prenatal diagnosis of 21-hydroxylase deficiency, first possible by steroid assay of the amniotic fluid, has utilized HLA typing for identification of loci (antigens B and DR) in close linkage with the 21-hydroxylase gene, and now increasingly relies on DNA analysis for linked HLA or C4 genes or for mutant 21-hydroxylase alleles directly by molecular genetic techniques. The most recent clinical advance is a program of combined prenatal diagnosis with karyotyping and suppression of fetal androgen production in genetic females by steroid administration to the mother. This is the first instance of an inborn metabolic error to be prenatally treated.
A series of 85 managed pregnancies is reported on, including accuracy of diagnosis, response of the mother to steroid treatment, and outcome for treated and untreated male and female fetuses (of 77 born by 6/91). Prenatal diagnosis by current techniques is accurate. Normal growth and development patterns postnatally suggest that dexamethasone treatment is safe. 相似文献