全文获取类型
收费全文 | 288篇 |
免费 | 4篇 |
国内免费 | 2篇 |
出版年
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2014年 | 6篇 |
2013年 | 3篇 |
2012年 | 10篇 |
2011年 | 17篇 |
2010年 | 14篇 |
2009年 | 17篇 |
2008年 | 12篇 |
2007年 | 22篇 |
2006年 | 19篇 |
2005年 | 26篇 |
2004年 | 21篇 |
2003年 | 7篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1993年 | 2篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1987年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1977年 | 2篇 |
1971年 | 4篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1961年 | 2篇 |
1959年 | 2篇 |
1958年 | 4篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1954年 | 2篇 |
1953年 | 4篇 |
1952年 | 4篇 |
1951年 | 1篇 |
1949年 | 4篇 |
1948年 | 1篇 |
1938年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有294条查询结果,搜索用时 15 毫秒
21.
Leem JY Park DS Suh EY Hur JH Oh HW Park HY 《Archives of insect biochemistry and physiology》2007,66(4):204-213
A new antimicrobial peptide, cryptonin, was isolated and characterized from the adult Korean blackish cicada, Cryptotympana dubia. It consists of 24 amino acid residues and has a molecular weight of 2,704 Da on mass spectroscopy. The predicted alpha-helical structure analysis and increased helix percent in 40% trifloroethanol of cryptonin suggests that it belongs to the typical linear alpha-helix forming peptide. Binding of the biotin-labeled cryptonin at the surface of E. coli cells and increased influx of propidium iodide in E. coli after cryptonin treatment indicates that it kills microbial cells by binding bacterial cell surfaces and disrupting the cell permeability. Cryptonin showed strong antibacterial (MIC 1.56-25 microg/ml) and antifungal (MIC 3.12-50 microg/ml) activities against tested bacteria and fungi including two antibiotic-resistant bacterial strains; methicilin-resistant S. aureus and vancomycin-resistant Enterococci (MIC 25 microg/ml, each). 相似文献
22.
The molecular mechanisms involved in the ability of yeast cells to adapt and respond to oxidative stress are of great interest
to the pharmaceutical, medical, food, and fermentation industries. In this study, we investigated the time-dependent, cellular
redox homeostasis ability to adapt to menadione-induced oxidative stress, using biochemical and proteomic approaches in Saccharomyces cerevisiae KNU5377. Time-dependent cell viability was inversely proportional to endogenous amounts of ROS measured by a fluorescence
assay with 2′,7′-dichlorofluorescin diacetate (DCFHDA), and was hypersensitive when cells were exposed to the compound for
60 min. Morphological changes, protein oxidation and lipid peroxidation were also observed. To overcome the unfavorable conditions
due to the presence of menadione, yeast cells activated a variety of cell rescue proteins including antioxidant enzymes, molecular
chaperones, energy-generating metabolic enzymes, and antioxidant molecules such as trehalose. Thus, these results show that
menadione causes ROS generation and high accumulation of cellular ROS levels, which affects cell viability and cell morphology
and there is a correlation between resistance to menadione and the high induction of cell rescue proteins after cells enter
into this physiological state, which provides a clue about the complex and dynamic stress response in yeast cells. 相似文献
23.
E Hyun SHIN Hyun Kyung KIM Chan PARK Dong‐Kyu LEE Hyesook KANG Kyu Sik CHANG 《Entomological Research》2011,41(4):157-160
The susceptibility of Culex tritaeniorhynchus collected from Gwangju, Jeollabuk Province, Republic of Korea (ROK) to insecticides was evaluated under laboratory conditions using ten insecticides (7 pyrethroids and 3 organophosphates) that are currently applied by local public health centers in the ROK. Based on the values of median lethal concentration (LC50), Cx. tritaeniorhynchus larvae were most susceptible to chlorpyrifos (0.006 ppm), fenitrothion (0.022 ppm), fenthion (0.035 ppm) and bifenthrin (0.038 ppm), and were least susceptible to esbiol (1.722 ppm). In comparative resistance tests, the resistance ratios (RRs) of seven insecticides were compared among each other using two strains of Cx. tritaeniorhynchus that were collected from the same locality during 1992 and 2010. Culex tritaeniorhynchus demonstrated significantly increased RRs to pyrethroids over time, while demonstrating decreased RRs among the organophosphates. Among the pyrethroids, permethrin had the highest RR values of 182.1‐ and 833.3‐fold differences, followed by etofenprox with RRs of 138.4‐ and 224.1‐fold differences in values of LC50 and concentration that produced 90% mortality (LC90), respectively. Culex tritaeniorhynchus strains demonstrated the least amount of change in susceptibility to the organophosphates, chlorpyrifos, fenitrothion and fenthion with 0.020‐, 0.019‐ and 0.001‐fold differences in resistance ratios (RRLC50), respectively. 相似文献
24.
E‐Hyun SHIN Wook‐Gyo LEE Kyu‐Sik CHANG Young‐Mi CHOI Hee‐Il LEE Longzhu JIN Jixu LI Longnan CHEN Dong‐Kyu LEE Chan PARK 《Entomological Research》2011,41(1):36-38
Adult mosquito surveillance was conducted using black light traps in August of 2006 and 2007 at Wangging county and Yanji city, Jilin Province, China to identify the distribution of anopheline mosquitoes in northern China. A total of 2459 female mosquitoes comprising three genera and eight species including Anopheles (Anopheles) lesteri, An. (Ano.) kleini, An. (Ano.) pullus, Culex inatomii, Cx. orientalis, Cx. pipiens, Cx. bitaeniorhynchus and Aedes vexans nipponii were collected. The most commonly collected species was An. kleini which had not been previously reported from China. Anopheles sinensis sensu stricto is commonly collected throughout China, but was not collected from these areas. 相似文献
25.
Cho O Choi KY Zylstra GJ Kim YS Kim SK Lee JH Sohn HY Kwon GS Kim YM Kim E 《Biochemical and biophysical research communications》2005,327(3):656-662
Sphingomonas yanoikuyae B1 possesses several different multicomponent oxygenases involved in metabolizing aromatic compounds. Six different pairs of genes encoding large and small subunits of oxygenase iron-sulfur protein components have previously been identified in a gene cluster involved in the degradation of both monocyclic and polycyclic aromatic hydrocarbons. Insertional inactivation of one of the oxygenase large subunit genes, bphA1c, results in a mutant strain unable to grow on naphthalene, phenanthrene, or salicylate. The knockout mutant accumulates salicylate from naphthalene and 1-hydroxy-2-naphthoic acid from phenanthrene indicating the loss of salicylate oxygenase activity. Complementation experiments verify that the salicylate oxygenase in S. yanoikuyae B1 is a three-component enzyme consisting of an oxygenase encoded by bphA2cA1c, a ferredoxin encoded by the adjacent bphA3, and a ferredoxin reductase encoded by bphA4 located over 25kb away. Expression of bphA3-bphA2c-bphA1c genes in Escherichia coli demonstrated the ability of salicylate oxygenase to convert salicylate to catechol and 3-, 4-, and 5-methylsalicylate to methylcatechols. 相似文献
26.
27.
28.
29.
30.
DONG‐SEOK KIM SOOK‐YOUNG KIM SEONG‐JOON MOON JIN‐HO CHUNG KYU‐HAN KIM KWANG‐HYUN CHO KYOUNG‐CHAN PARK 《Pigment cell & melanoma research》2001,14(2):110-115
Ceramide is a bioactive sphingolipid that mediates a variety of cell functions. However, the effects of ceramide on cell growth and the melanogenesis of melanocytes are not known. In the present study, we investigated the actions of cell‐permeable ceramide and its possible role in the signaling pathway of a spontaneously immortalized mouse melanocyte cell line, Mel‐Ab. Our results show that C2‐ceramide inhibits DNA synthesis in Mel‐Ab cells and G361 human melanoma cells in a dose‐dependent manner. Cell cycle analysis confirmed the inhibition of DNA synthesis by a reduction in the S phase. To investigate the ceramide signaling pathway, we studied whether C2‐ceramide is able to influence extracellular signal‐regulated kinase (ERK) and/or Akt/protein kinase B (PKB) activation. We demonstrated that phosphorylated Akt/PKB is decreased by C2‐ceramide, whereas phosphorylated ERK was only slightly affected. Therefore, the C2‐ceramide‐induced inactivation of Akt/PKB may be closely related to the reduced cell proliferation of Mel‐Ab cells. Furthermore, we assessed the effects of C2‐ceramide on the pigmentation of Mel‐Ab cells. The results obtained showed that the melanin content of cells was significantly reduced by C2‐ceramide at concentrations in the range of 1–10 μM, and that the pigmentation‐inhibiting effect of C2‐ceramide is much greater than that of kojic acid at 1–100 μM. In addition, we found that the activity of tyrosinase is reduced by C2‐ceramide treatment. Our results demonstrate that C2‐ceramide reduces the pigmentation of Mel‐Ab cells by inhibiting tyrosinase activity. 相似文献