全文获取类型
收费全文 | 429篇 |
免费 | 30篇 |
出版年
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 20篇 |
2017年 | 7篇 |
2016年 | 16篇 |
2015年 | 12篇 |
2014年 | 30篇 |
2013年 | 31篇 |
2012年 | 28篇 |
2011年 | 27篇 |
2010年 | 16篇 |
2009年 | 17篇 |
2008年 | 20篇 |
2007年 | 19篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 15篇 |
2002年 | 5篇 |
2001年 | 10篇 |
2000年 | 23篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 10篇 |
1979年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1956年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有459条查询结果,搜索用时 93 毫秒
81.
82.
83.
Ujjal Das Krishnendu Manna Amitava Khan Mahuya Sinha Sushobhan Biswas Aaveri Sengupta 《Free radical research》2017,51(1):47-63
The present study was aimed to evaluate the radioprotective effect of ferulic acid (FA), a naturally occurring plant flavonoid in terms of DNA damage and damage related alterations of repair pathways by gamma radiation. FA was administered at a dose of 50?mg/kg body weight for five consecutive days prior to exposing the swiss albino mice to a single dose of 10?Gy gamma radiation. Ionising radiation induces oxidative damage manifested by decreased expression of Cu, Zn-SOD (SOD stands for super oxide dismutase), Mn-SOD and catalase. Gamma radiation promulgated reactive oxygen species (ROS) mediated DNA damage and modified repair pathways. ROS enhanced nuclear translocation of p53, activated ATM (ataxia telangiectasia-mutated protein), increased expression of GADD45a (growth arrest and DNA-damage-inducible protein) gene and inactivated Non homologous end joining (NHEJ) repair pathway. The comet formation in irradiated mice peripheral blood mononuclear cells (PBMC) reiterated the DNA damage in IR exposed groups. FA pretreatment significantly prevented the comet formation and regulated the nuclear translocation of p53, inhibited ATM activation and expression of GADD45a gene. FA promoted the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and activated NHEJ repair pathway to overcome ROS mediated oxidative stress and DNA damage. Therefore, the current study stated that FA can challenge the oxidative stress by (i) inducing nuclear translocation of Nrf2, (ii) scavenging ROS, and (iii) activating NHEJ DNA repair process. 相似文献
84.
The challenges of understanding glycolipid functions: An open outlook based on molecular simulations
Moutusi Manna Tomasz Róg Ilpo Vattulainen 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2014,1841(8):1130-1145
Glycolipids are the most complex lipid type in cell membranes, characterized by a great diversity of different structures and functions. The underlying atomistic/molecular interactions and mechanisms associated with these functions are not well understood. Here we discuss how atomistic and molecular simulations can be used to shed light on the role of glycolipids in membrane structure and dynamics, receptor function, and other phenomena related to emergence of diseases such as Parkinson's. The cases we discuss highlight the challenge to understand how glycolipids function in cell membranes, and the significant added value that one would gain by bridging molecular simulations with experiments. This article is part of a Special Issue entitled Tools to study lipid functions. 相似文献
85.
Suman Kanungo Bandana Sen Thandavarayan Ramamurthy Dipika Sur Byomkesh Manna Gururaja P. Pazhani Goutam Chowdhury Puja Jhunjhunwala Ranjan K. Nandy Hemanta Koley Mihir Kumar Bhattacharya Sanjay Gupta Gaurav Goel Bindu Dey Thungapathra M G. Balakrish Nair Amit Ghosh Dilip Mahalanabis 《PloS one》2014,9(7)
Background
A live oral cholera vaccine VA 1.4 developed from a non-toxigenic Vibrio cholerae O1 El Tor strain using ctxB gene insertion was further developed into a clinical product following cGMP and was evaluated in a double-blind randomized placebo controlled parallel group two arm trial with allocation ratio of 1∶1 for safety and immunogenicity in men and women aged 18–60 years from Kolkata, India.Method
A lyophilized dose of 1.9×109 CFU (n = 44) or a placebo (n = 43) reconstituted with a diluent was administered within 5 minutes of drinking 100 ml of a buffer solution made of sodium bicarbonate and ascorbic acid and a second dose on day 14.Result
The vaccine did not elicit any diarrhea related adverse events. Other adverse events were rare, mild and similar in two groups. One subject in the vaccine group excreted the vaccine strain on the second day after first dose. The proportion of participants who seroconverted (i.e. had 4-folds or higher rise in reciprocal titre) in the vaccine group were 65.9% (95% CI: 50.1%–79.5%) at both 7 days (i.e. after 1st dose) and 21 days (i.e. after 2nd dose). None of the placebo recipients seroconverted. Anti-cholera toxin antibody was detected in very few recipients of the vaccine.Conclusion
This study demonstrates that VA 1.4 at a single dose of 1.9×109 is safe and immunogenic in adults from a cholera endemic region. No additional benefit after two doses was seen.Trial Registration
Clinical Trials Registry-India, National Institute of Medical Statistics (Indian Council of Medical Research) CTRI/2012/04/002582 相似文献86.
87.
88.
Nutritional and cultural conditions for production of poly-3-hydroxybutyric acid byAzotobacter chroococcum 总被引:1,自引:0,他引:1
Free-living nitrogen-fixing bacteria have been identified as a potential source of poly-3-hydroxybutyric acid (PHB). Systematic
study of this ability of N2-fixing organisms has lead to the isolation of an efficient strain, identified asAzotobacter chroococcum. Nutritional requirements and cultural conditions for optimal production of PHB by this strain under laboratory conditions
were determined. In N-free liquid medium containing 2% glucose, the strain accumulated PHB up to 68% of its cell dry mass.
Glucose and mannitol were found to be the best carbon sources, while organic nitrogen compounds were preferred as nitrogen
source. Maximum yield (3.3 g/L) was obtained with 0.2% bactopeptone supplementation. Inorganic phosphate at a concentration
suboptimal for growth had some growth-promoting effect. Under oxygen limiting conditions, biomass production was enhanced
but a different response was obtained for PHB production. 相似文献
89.
Datta S Adak R Chakraborty P Haldar AK Bhattacharjee S Chakraborty A Roy S Manna M 《Experimental parasitology》2012,130(1):39-47
The present study intends to evaluate the role of radio-attenuated leishmania parasites as immunoprophylactic agents for experimental murine visceral leishmaniasis. BALB/c mice were immunized with gamma (γ)-irradiated Leishmania donovani. A second immunization was given after 15 days of first immunization. After two immunizations, mice were infected with virulent L. donovani promastigotes. Protection against Kala-azar (KA) was estimated from spleen and liver parasitic burden along with the measurement of nitrite and superoxide anion generation by isolation of splenocytes and also by T-lymphocyte helper 1(Th1) and T-lymphocyte helper 2(Th2) cytokines release from the experimental groups. It was observed that BALB/c mice having prior immunization with radio-attenuated parasites showed protection against L. donovani infection through higher expression of Th1 cytokines and suppression of Th2 cytokines along with the generation of protective free radicals. The group of mice without prior priming with radio-attenuated parasites surrendered to the disease. Thus it can be concluded that radio-attenuated L. donovani may be used for. 相似文献
90.
S Mohanty S Saha D Md S Hossain A Adhikary S Mukherjee A Manna S Chakraborty M Mazumdar P Ray K Das J Chakraborty G Sa T Das 《Cell death & disease》2014,5(1):e1021
With the existing knowledge of ATM''s role in therapeutic resistance, the present study aimed at identifying the molecular mechanisms that influence ATM to oscillate between chemoresistance and chemosensitivity. We observed that the redox status of tumors functions as a major determinant of ATM-dependent ‘resistance-to-apoptosis'' molecular switch. At a low reactive oxygen species (ROS) condition during genotoxic insult, the ATM/sumoylated-IKKγ interaction induced NFκB activation that resisted JNK-mediated apoptosis, whereas increasing cellular ROS restored ATM/JNK apoptotic signaling. A search for the upstream missing link revealed that high ROS induces oxidation and ubiquitin-mediated degradation of PIASγ, thereby disrupting PIASγ-IKKγ cross talk, a pre-requisite for IKKγ sumoylation and subsequent NFκB activation. Interruption in the PIASγ-mediated resistance pathway channels ATM signaling toward ATM/JNK pro-death circuitry. These in vitro results also translated to sensitive and resistant tumor allograft mouse models in which low ROS-induced resistance was over-ruled in PIASγ knockout tumors, while its overexpression inhibited high ROS-dependent apoptotic cues. Cumulatively, our findings identified an unappreciated yet critical combinatorial function of cellular ROS and PIASγ in regulating ATM-mediated chemosensitization of resistant tumors. Thus, therapeutic strategies employing ROS upregulation to inhibit PIASγ during genotoxic therapy may, in future, help to eliminate the problems of NFκB-mediated tumor drug resistance. 相似文献