全文获取类型
收费全文 | 194篇 |
免费 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 14篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 15篇 |
2012年 | 19篇 |
2011年 | 9篇 |
2010年 | 10篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1964年 | 2篇 |
排序方式: 共有202条查询结果,搜索用时 31 毫秒
11.
Palanduz S Sever MS Oztürk S Taşçioğlu C Karan MA Sönmez G Cefle K Güler K 《Cell biology and toxicology》1999,15(1):13-17
We analyzed the induction of sister chromatid exchange (SCE) by cyclosporin A (CsA) as a marker of genotoxic potential. In 30 patients undergoing renal transplantation, SCE induction was tested before the introduction of CsA and 3 months later. We found that SCE frequency increased significantly at the end of 3 months. To our knowledge, this is the first study demonstrating in vivo induction of SCE by CsA in humans. We conclude that CsA has a genotoxic potential on human lymphocytes. 相似文献
12.
13.
Karan D Chen SJ Johansson SL Singh AP Paralkar VM Lin MF Batra SK 《Biochemical and biophysical research communications》2003,305(3):598-604
As a part of the study to identify genes associated with hormone-refractory stage of human prostate cancer, we have recently identified several genetic and epigenetic changes that seem to be associated with the progression of androgen-sensitive to androgen-independent prostate tumor cells. In the present study, we report a novel gene, macrophage inhibitory cytokine-1 (MIC-1) also known as prostate derived factor (PDF), that was highly expressed in androgen-independent LNCaP-C81 cells and its metastatic variant LNCaP-Ln3 compared to androgen-sensitive LNCaP-C33 cells. The MIC-1/PDF expression was dysregulated (very low to non-detectable) in the androgen-independent PC3 and DU145 cells. Interestingly, serum factors demonstrated a differential regulation of MIC-1/PDF in the androgen-sensitive and the androgen-independent cells of LNCaP cells. Immunohistochemical analysis on 15 prostatic adenocarcinomas showed a weak staining in the benign prostatic glandular area (intensity score 2.38+/-0.25; n=13), while the immunoreactivity was significantly stronger (p<0.05) in areas of adenocarcinoma (score 7.33+/-0.88; n=15). Altogether, these data suggest that the serum factors (including androgens and cytokines) might contribute to the regulation of the MIC-1/PDF gene that seems to be associated with the progression of prostate cancer. 相似文献
14.
In this paper we introduce a preliminary work in which a redox mediator containing polyvinylferrocene immobilized on silica gel particles is synthesized. Carbon paste electrodes prepared with this polymeric mediator were studied for their stability in aqueous media for a month. The results indicated that approximately 70% of the initial activity was retained after a month. A steady state amperometric measurement of this carbon paste electrode containing this mediator and glucose oxidase at different potentials showed a linear relationship at elevated glucose concentration. 相似文献
15.
Dev Karan Neena Dahiya Ashok K. Munjal Patricia Gibert Brigitte Moreteau Ravi Parkash Jean R. David 《Evolution; international journal of organic evolution》1998,52(3):825-831
Desiccation and starvation tolerance were measured along latitudinal transects in three Drosophilid species (Drosophila ananassae, D. melanogaster, and Zaprionus indianus) of the Indian subcontinent. In each case, significant latitudinal clines were observed; desiccation tolerance increased with latitude while starvation tolerance decreased. Such field observations suggest that desiccation and starvation tolerance are fitness related traits that are independently selected in nature and genetically independent. It was, however, difficult to relate these genetic changes with precise climatic variables, except winter temperature. The overall negative correlation between the two traits, which was evidenced in natural populations, contrasts with a positive correlation generally observed in various laboratory selection experiments and that also seems to exist between different species. These observations point to the difficulty of interpreting correlations among fitness-related traits when different evolutionary levels are compared, and also different sets of data, that is, field versus laboratory studies. 相似文献
16.
17.
Rachna Khurana Ram Karan Anand Kumar S. K. Khare 《Journal of plant biochemistry and biotechnology.》2010,19(2):229-233
Indian herbal plant species Lantana indica, Adhatoda vasica, Pandanus furcatus, Tylophora indica and Centella asiatica, traditionally used in ethno medicines to treat common infections and various disorders, have been studied for their antimicrobial and antioxidant activity. The methanolic extracts of the plant leaves exhibited significant and dose-dependent antioxidant activities in DPPH radical scavenging, ferric ion reducing and phosphomolybdate assays. These leaf extracts showed antimicrobial activity against selected Gram +ve and Gram ?ve bacterial strains. A. vasica and L. indica extracts possessed maximum antioxidant and antimicrobial activity, respectively. The activities could be correlated to phenolics and flavonoid content of the leaf extracts which ranged from 30.25 to 91.98 mg GAE g?1 dw leaf extract and 2.67 to 96.45 mg RE g?1 dw leaf extract respectively. The aqueous extracts of plant leaves significantly protected the DNA damage against the oxidative damage caused by hydroxyl radicals. 相似文献
18.
Multiple classification performance of juvenile chimpanzees,normal children,and retarded children 总被引:1,自引:0,他引:1
Anthony D. Hall John T. Braggio James P. Buchanan Ronald D. Nadler David Karan J. Bob Sams 《International journal of primatology》1980,1(4):345-359
The cognitive capacities of juvenile chimpanzees, normal children, and retarded children were evaluated by using a nonverbal,
Piagetian-type multiple classification task. The three groups of subjects were tested with the same two by two stimulus matrix,
which was formed by combining two different colors with two different shapes. On each problem the subjects were required to
select one of four stimulus items from the response tray and place it inside the empty cell of the stimulus matrix. It was
found that the human and nonhuman primates tested were able to select objects with correct color and shape cues (C+/S+)significantly more often than the other objects with only color cues correct (C+/S-), only shape cues correct (C-/S+), or neither cue correct (C-/S-). Although the two groups of human children were able to select the C+/S+ objects about 100% of the time by the end of testing, the normal children required significantly fewer problems than the
retarded children. The juvenile chimpanzees needed significantly more problems than the human subjects before they consistently
selected the C+/S+ object on the first trial and attained a level of correct responding that was above chance. Moreover, their level of performance
did not exceed 70% correct. These data suggest that the human children (both normal and retarded) used a conceptual strategy,
while the juvenile chimpanzees employed a perceptual strategy to solve the multiple classification problems. The relationship
between language and conceptual problem-solving strategies for Piagetiantype tasks is discussed.
Portions of the data reported in this study were presented at the Annual Meeting of the Southern Psychological Association,
Atlanta, Georgia, March 15–18, 1978. 相似文献
19.
20.
Pratik Satya Maya Karan Debabrata Sarkar M. K. Sinha 《Plant Systematics and Evolution》2012,298(7):1257-1270
Two tetraploid species of Hibiscus section Furcaria, H. acetosella and H. radiatus, have an AABB genomic constitution. The diploid species, H. cannabinus (AA) and H. surattensis (BB), were hybridized to develop interspecific alloploid (AB) hybrids. The synthetic interspecific hybrid exhibited intermediate morphological characters, with expression of domestication-related traits, but exhibited higher genomic association with the B genome donor. Evolution of allopolyploids in section Furcaria was found to be associated with mutations in repetitive sequences, leading to higher variation in the tetraploid genome. Allopolyploidization was observed to be associated with both loss of repetitive sequences and appearance of new alleles. Genetic diversity analysis using ISSR and cross-species SSR markers revealed a closer association of diploid genomes and high variability of tetraploid genomes. The evolution of AABB tetraploids in this section possibly took place by hybridization of the A and B genome in geographically isolated regions. 相似文献