全文获取类型
收费全文 | 799篇 |
免费 | 30篇 |
国内免费 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 12篇 |
2015年 | 24篇 |
2014年 | 41篇 |
2013年 | 58篇 |
2012年 | 52篇 |
2011年 | 44篇 |
2010年 | 22篇 |
2009年 | 25篇 |
2008年 | 43篇 |
2007年 | 48篇 |
2006年 | 43篇 |
2005年 | 74篇 |
2004年 | 52篇 |
2003年 | 47篇 |
2002年 | 55篇 |
2001年 | 6篇 |
2000年 | 17篇 |
1999年 | 10篇 |
1998年 | 14篇 |
1997年 | 13篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 4篇 |
1967年 | 1篇 |
排序方式: 共有830条查询结果,搜索用时 17 毫秒
821.
Pioglitazone inhibits cancer cell growth through STAT3 inhibition and enhanced AIF expression via a PPARγ‐independent pathway 下载免费PDF全文
822.
Masanobu Yamamoto Yutaka Ichikawa Tadamichi Oba 《Palaeogeography, Palaeoclimatology, Palaeoecology》2005,229(3):179-186
In order to understand the responses of terrestrial vegetation in central Japan to global climate changes, we have generated the record of lignin composition from Core MD01-2421 off central Japan in the NW Pacific during the last 145,000 years by tetramethylammonium hydroxide (TMAH)-pyrolysis-gas chromatography-mass spectrometry (GC/MS). The relative abundance of lignin was significantly low in early MIS-1 and MIS-5e and higher in MIS-5c to early MIS-4. This reflects glacial-interglacial changes in sea level and riverine runoff. The ratio of syringyl (S)- to vanillyl (V)-phenols (S / V ratio), which is a contribution index of angiosperms against gymnosperms, was lower in MIS-2, MIS-4 and MIS-6, reflecting the glacial-interglacial variation of air temperature. The ratio of cinnamyl (C)- to vanillyl (V)-phenols (C / V ratio), which indicates the contribution of grasses, was higher in late MIS-2, early-mid MIS-3 and MIS-6. The periods of higher C / V ratio correspond to the periods of lower sea surface temperatures (SSTs), suggesting a dry and cold climate in late MIS-2, mid-MIS-3 and MIS-6. 相似文献
823.
Streptococcus pyogenes upregulates arginine catabolism to exert its pathogenesis on the skin surface
824.
825.
Astringent compounds were applied to oral epithelium of theclawed toad, Xenopus laevis, and rapidly rising and highly sensitiveresponses could be recorded from the whole glossopharyngealnerve, but not at all from the trigeminal nerve. The responseto 10 mM tannic acid decreased progressively with repetitiveapplication. These responses to tannic acid, however, recoveredcompletely by treating with chemicals capable of forming stronghydrogen and hydrophobic bonds. These chemical bondings aregenerally recognized as a model for polyphenol (tannin)-proteininteractions based on physico-chemical measurements in vitro.The high affinities of these chemicals for tannic acid may beeffective in releasing both bonds in the interaction of tannicacid with the receptor molecules. Our results provide in vivoevidence for this model. Chem. Senses 21: 459465, 1996. 相似文献
826.
827.
828.
829.
Hideki Komatsu Tadao Kakizoe Tadao Niijima Takashi Kawachi Takashi Sugimura 《Mutation research》1982,93(2):439-446
The effect of dietary restriction on sperm-head morphology in BDF1 mice was studied. The food intake of the ice was restricted to 2.0 or 1.5 g/day during the whole experimental period, while control animals were fed ad libitum. The average food intake of control mice was 4.2 ± 0.5 g/day. The frequencies of abnormal sperm in food-restricted mice remained at the basal level for the first 2 weeks. In week 3, the frequencies of abnormal sperm increased only in mice on the severely restricted diet (1.5 g/day). In week 5, the frequencies of abnormal sperm increased significantly in both restricted groups, and a negative correlation between the food intake and the frequency of abnormal sperm was observed. These results suggest that sperm abnormalities are not always the results of exogenous mutagen-induced damage 相似文献
830.
Yohei Shimura Yuu Hirose Naomi Misawa Yasunori Osana Hiroshi Katoh Haruyo Yamaguchi Masanobu Kawachi 《DNA research》2015,22(6):403-412
The cyanobacterial genus Leptolyngbya is widely distributed throughout terrestrial environments and freshwater. Because environmental factors, such as oxygen level, available water content, and light intensity, vary between soil surface and water bodies, terrestrial Leptolyngbya should have genomic differences with freshwater species to adapt to a land habitat. To study the genomic features of Leptolyngbya species, we determined the complete genome sequence of the terrestrial strain Leptolyngbya sp. NIES-2104 and compared it with that of the near-complete sequence of the freshwater Leptolyngbya boryana PCC 6306. The greatest differences between these two strains were the presence or absence of a nitrogen fixation gene cluster for anaerobic nitrogen fixation and several genes for tetrapyrrole synthesis, which can operate under micro-oxic conditions. These differences might reflect differences in oxygen levels where these strains live. Both strains have the genes for trehalose biosynthesis, but only Leptolyngbya sp. NIES-2104 has genetic capacity to produce a mycosporine-like amino acid, mycosporine-glycine. Mycosporine-glycine has an antioxidant action, which may contribute to adaptation to terrestrial conditions. These features of the genomes yielded additional insights into the classification and physiological characteristics of these strains. 相似文献