全文获取类型
收费全文 | 5632篇 |
免费 | 424篇 |
国内免费 | 362篇 |
专业分类
6418篇 |
出版年
2024年 | 12篇 |
2023年 | 66篇 |
2022年 | 158篇 |
2021年 | 284篇 |
2020年 | 202篇 |
2019年 | 229篇 |
2018年 | 218篇 |
2017年 | 185篇 |
2016年 | 276篇 |
2015年 | 354篇 |
2014年 | 440篇 |
2013年 | 451篇 |
2012年 | 477篇 |
2011年 | 426篇 |
2010年 | 259篇 |
2009年 | 224篇 |
2008年 | 274篇 |
2007年 | 231篇 |
2006年 | 172篇 |
2005年 | 129篇 |
2004年 | 137篇 |
2003年 | 124篇 |
2002年 | 112篇 |
2001年 | 98篇 |
2000年 | 89篇 |
1999年 | 92篇 |
1998年 | 63篇 |
1997年 | 61篇 |
1996年 | 39篇 |
1995年 | 51篇 |
1994年 | 55篇 |
1993年 | 53篇 |
1992年 | 67篇 |
1991年 | 48篇 |
1990年 | 34篇 |
1989年 | 29篇 |
1988年 | 28篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 22篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 18篇 |
1978年 | 8篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1972年 | 5篇 |
排序方式: 共有6418条查询结果,搜索用时 0 毫秒
51.
柠檬酸是利用微生物代谢生产的一种极为重要的有机酸.广泛应用于食品、饮料、化工、冶金、印染等各个领域。在国外,近10年来,利用固定化细胞生产柠檬酸已获得较广泛的研究〔1-6〕,国内也有学者指出,柠檬酸发酵的趋向是利用固定化细胞进行连续化生产⑺。而国内这方面的研究报道很少〔8,9〕。我们利用海藻酸钙凝胶包埋固定化黑曲霉细胞生产柠檬酸.探讨了碳源种类及其浓度对固定化细胞生产柠檬酸的影响。现将结果报道如下。 相似文献
52.
Yaoyao Hou Yingjun Fan Xian Xia Jicheng Pan Jianjun Hou Xixia Liu Xinpeng Chen 《Acta biochimica et biophysica Sinica》2021,(8):1037-1043
Ubiquitin-specific protease 31 (USP31) is a member of deubiquitinase family that is involved in nuclear factor-κB activation and sarcomagenesis.However,little i... 相似文献
53.
54.
55.
56.
Yujie Huang Ruijuan Liu Xuechao Han Xiaoyan Hou Yonghao Tian Weifang Zhang 《International journal of biological sciences》2022,18(1):112
Persistent infection with high-risk human papillomavirus (HPV) is the main risk factor for cervical cancer. Our mass spectrometry data showed that the Ras-associated binding protein Rab31 was upregulated by HPV; however, little is known regarding the role of Rab31 in the metastasis of cervical cancer cells. In this study, we showed that Rab31 was highly expressed in cervical cancer tissues and cells, and both HPV E6 and E7 promoted the expression of Rab31. Rab31 knockdown inhibited while Rab31 overexpression promoted the migration and invasion capabilities of cervical cancer cells. Additionally, Rab31 knockdown inhibited the epithelial-mesenchymal transition (EMT) and cytoskeletal rearrangement in cervical cancer cells. Furthermore, Rab31 interacted with mitogen-activated protein kinase 6 (MAPK6), and Rab31 knockdown inhibited the expression of MAPK6, which was mainly localized in the cytoplasm. More importantly, Rab31 knockdown promoted and Rab31 overexpression inhibited MAPK6 degradation. Accordingly, MAPK6 overexpression restored the decreased migration potential caused by Rab31 knockdown. Finally, a xenograft mouse model showed that Rab31 knockdown in cervical cancer cells led to reduced tumor growth and impaired lung and liver metastasis in vivo. In conclusion, Rab31 plays a crucial role in cervical cancer metastasis by inhibiting MAPK6 degradation. Thus, Rab31 may serve as a novel therapeutic target to manage cervical cancer. 相似文献
57.
Cheng Long Juan Chen Hua Zhou Tao Jiang Xiang Fang Dong Hou 《Cell cycle (Georgetown, Tex.)》2019,18(3):346-358
Osteosarcoma (OS) is one of the aggressive malignancies for young adults. Cdc20 (cell division cycle 20 homologue) has been reported to exhibit an oncogenic role in OS, suggesting that inhibition of Cdc20 could be a novel strategy for the treatment of OS. Since Cdc20 inhibitors have side effects, it is important to discover the new CDC20 inhibitors with non-toxic nature. In the present study, we determine whether natural agent diosgenin is an inhibitor of Cdc20 in OS cells. We performed MTT, FACS, Wound healing assay, Transwell, Western blotting, transfection assays in our study. We found diosgenin inhibited cell growth and induced apoptosis. Moreover, diosgenin exposure led to inhibition of cell migration and invasion. Notably, diosgenin inhibited the expression of Cdc20 in OS cells. Overexpression of Cdc20 abrogated the inhibition of cell growth and invasion induced by diosgenin. Our data reveal that inhibition of Cdc20 by diosgenin could be helpful for the treatment of patients with OS. 相似文献
58.
双价外壳蛋白基因植物表达载体的构建及马铃薯转基因植株的鉴定 总被引:10,自引:0,他引:10
在克隆了马铃薯X病毒(PVX)、马铃薯Y 病毒(PVY)和马铃薯卷叶病毒(PLRV)的外壳蛋白基因的基础上,构建同时包含PVX和PVY 与PVY 和PLRV 两个外壳蛋白基因植物表达框架的表达载体,通过农杆菌(Agrobacterium tumefaciens)介导转化烟草(Nicotianatabacum )和生产上常用的几个马铃薯(Solanum tuberosum )优良品种:“Favorita”、“虎头”、“克4”。经PCR检测证明外源基因已整合到植物的染色体上,得到批量转基因植株。在转PVX+PVY 外壳蛋白基因的烟草上接种PVX (5 μg/m L)、PVY(20 μg/m L)病毒,得到有一定抗性的植株 相似文献
59.
60.