全文获取类型
收费全文 | 3581篇 |
免费 | 192篇 |
国内免费 | 7篇 |
出版年
2022年 | 15篇 |
2021年 | 35篇 |
2020年 | 24篇 |
2019年 | 34篇 |
2018年 | 57篇 |
2017年 | 35篇 |
2016年 | 59篇 |
2015年 | 107篇 |
2014年 | 116篇 |
2013年 | 203篇 |
2012年 | 179篇 |
2011年 | 244篇 |
2010年 | 138篇 |
2009年 | 157篇 |
2008年 | 222篇 |
2007年 | 244篇 |
2006年 | 228篇 |
2005年 | 240篇 |
2004年 | 235篇 |
2003年 | 222篇 |
2002年 | 221篇 |
2001年 | 37篇 |
2000年 | 39篇 |
1999年 | 49篇 |
1998年 | 61篇 |
1997年 | 31篇 |
1996年 | 41篇 |
1995年 | 42篇 |
1994年 | 35篇 |
1993年 | 48篇 |
1992年 | 35篇 |
1991年 | 26篇 |
1990年 | 30篇 |
1989年 | 27篇 |
1988年 | 28篇 |
1987年 | 29篇 |
1986年 | 27篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 19篇 |
1982年 | 15篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1975年 | 7篇 |
1973年 | 6篇 |
1968年 | 7篇 |
1965年 | 5篇 |
排序方式: 共有3780条查询结果,搜索用时 15 毫秒
81.
Hajime Sakaguchi Hiromi Hagiwara Yoshihiro Fukumori Yutaka Tamaura Minoru Funaki Shigehisa Hirose 《FEMS microbiology letters》1993,107(2-3):169-173
Abstract The magnetic bacterium Magnetospirillum magnetotacticum prefers a microaerobic habitat and should be able to sense oxygen. Therefore, the bacterium was cultured under atmospheres containing 0–5% O2 and analyzed for oxygen-dependent changes in the levels of its protein components by sodium dodecyl sulfate-polyccrylamide gel electrophoresis (SDS-PAGE). The analysis revealed a marked anaerobic induction of a 140-kDa protein, which was suppressed when M. magnetotacticum was switched from microaerobic (<1% O2 ) to aerobic (>1% O2 ) growth conditions. Although its function remains to be determined, the 140-kDa protein may serve as a useful tool to gain insight into the physiology of the organism. 相似文献
82.
83.
Masahiko Saito Tomohiro Fukuhara Satoshi Kamimura Hiroyuki Ichikawa Hiroyuki Yoshida Tomoyuki Koganezawa Yutaka Ie Yasunari Tamai Hyung Do Kim Hideo Ohkita Itaru Osaka 《Liver Transplantation》2020,10(7)
Controlling the energetics and backbone order of semiconducting polymers is essential for the performance improvement of polymer‐based solar cells. The use of fluorine as the substituent for the backbone is known to effectively deepen the molecular orbital energy levels and coplanarize the backbone by noncovalent interactions with sulfur of the thiophene ring. In this work, novel semiconducting polymers are designed and synthesized based on difluoronaphthobisthiadiazole (FNTz) as a new family of naphthobisthiadiazole (NTz)–quaterthiophene copolymer systems, which are one of the highest performing polymers in solar cells. The effect of the fluorination position on the energetics and backbone order is systematically studied. It is found that the dependence of the solar cell fill factor on the active layer thickness is very sensitive to the fluorination position. It is thus further investigated and discussed how the structural features of the polymers influence the photovoltaic parameters as well as the diode characteristics and bimolecular recombination. Further, the polymer with fluorine on both the naphthobisthiadiazole and quaterthiophene moieties exhibits a quite high power conversion efficiency of 10.8% in solar cells in combination with a fullerene. It is believed that the results would offer new insights into the development of semiconducting polymers. 相似文献
84.
85.
Journal of Plant Research - The article Molecular mechanisms mediating root hydrotropism 相似文献
86.
Takumi Chinen Kaho Yamazaki Kaho Hashimoto Ken Fujii Koki Watanabe Yutaka Takeda Shohei Yamamoto Yuka Nozaki Yuki Tsuchiya Daisuke Takao Daiju Kitagawa 《The Journal of cell biology》2021,220(2)
The pericentriolar material (PCM) that accumulates around the centriole expands during mitosis and nucleates microtubules. Here, we show the cooperative roles of the centriole and PCM scaffold proteins, pericentrin and CDK5RAP2, in the recruitment of CEP192 to spindle poles during mitosis. Systematic depletion of PCM proteins revealed that CEP192, but not pericentrin and/or CDK5RAP2, was crucial for bipolar spindle assembly in HeLa, RPE1, and A549 cells with centrioles. Upon double depletion of pericentrin and CDK5RAP2, CEP192 that remained at centriole walls was sufficient for bipolar spindle formation. In contrast, through centriole removal, we found that pericentrin and CDK5RAP2 recruited CEP192 at the acentriolar spindle pole and facilitated bipolar spindle formation in mitotic cells with one centrosome. Furthermore, the perturbation of PLK1, a critical kinase for PCM assembly, efficiently suppressed bipolar spindle formation in mitotic cells with one centrosome. Overall, these data suggest that the centriole and PCM scaffold proteins cooperatively recruit CEP192 to spindle poles and facilitate bipolar spindle formation. 相似文献
87.
Takahashi Yumiko Sarkar Juli Yamada Jumpei Matsunaga Yutaka Nonaka Yudai Banjo Mai Sakaguchi Ryo Shinya Terunaga Hatta Hideo 《Journal of physiology and biochemistry》2021,77(3):469-480
Journal of Physiology and Biochemistry - To identify factors that influence post-exercise muscle glycogen repletion, we compared the glycogen recovery after level running with downhill running, an... 相似文献
88.
89.
90.