全文获取类型
收费全文 | 9338篇 |
免费 | 627篇 |
国内免费 | 689篇 |
出版年
2024年 | 17篇 |
2023年 | 99篇 |
2022年 | 219篇 |
2021年 | 447篇 |
2020年 | 312篇 |
2019年 | 385篇 |
2018年 | 371篇 |
2017年 | 282篇 |
2016年 | 363篇 |
2015年 | 587篇 |
2014年 | 678篇 |
2013年 | 735篇 |
2012年 | 832篇 |
2011年 | 786篇 |
2010年 | 458篇 |
2009年 | 427篇 |
2008年 | 489篇 |
2007年 | 408篇 |
2006年 | 367篇 |
2005年 | 308篇 |
2004年 | 259篇 |
2003年 | 237篇 |
2002年 | 187篇 |
2001年 | 174篇 |
2000年 | 151篇 |
1999年 | 141篇 |
1998年 | 104篇 |
1997年 | 95篇 |
1996年 | 83篇 |
1995年 | 73篇 |
1994年 | 82篇 |
1993年 | 66篇 |
1992年 | 71篇 |
1991年 | 66篇 |
1990年 | 66篇 |
1989年 | 52篇 |
1988年 | 32篇 |
1987年 | 35篇 |
1986年 | 22篇 |
1985年 | 27篇 |
1984年 | 11篇 |
1983年 | 17篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1950年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 879 毫秒
151.
152.
Tao Cong-Qi Ding Yi Zhao Yang-Jie Cui Heng-Lin 《Journal of microbiology (Seoul, Korea)》2020,58(2):105-112
Journal of Microbiology - Two halophilic archaeal strains, SHR37T and NEN6, were isolated from salt lakes located in the Tibet and Xinjiang regions of China. The two strains were found to form a... 相似文献
153.
Yanan Liu Tongjun Sun Yulin Sun Yanjun Zhang Ana Radoji
i Yuli Ding Hainan Tian Xingchuan Huang Jiameng Lan Siyu Chen Alberto Ruiz Orduna Kewei Zhang Reinhard Jetter Xin Li Yuelin Zhang 《The Plant cell》2020,32(12):4002
The plant defense hormone salicylic acid (SA) is perceived by two classes of receptors, NPR1 and NPR3/NPR4. They function in two parallel pathways to regulate SA-induced defense gene expression. To better understand the roles of the SA receptors in plant defense, we systematically analyzed their contributions to different aspects of Arabidopsis (Arabidopsis thaliana) plant immunity using the SA-insensitive npr1-1 npr4-4D double mutant. We found that perception of SA by NPR1 and NPR4 is required for activation of N-hydroxypipecolic acid biosynthesis, which is essential for inducing systemic acquired resistance. In addition, both pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) are severely compromised in the npr1-1 npr4-4D double mutant. Interestingly, the PTI and ETI attenuation in npr1-1 npr4-4D is more dramatic compared with the SA-induction deficient2-1 (sid2-1) mutant, suggesting that the perception of residual levels of SA in sid2-1 also contributes to immunity. Furthermore, NPR1 and NPR4 are involved in positive feedback amplification of SA biosynthesis and regulation of SA homeostasis through modifications including 5-hydroxylation and glycosylation. Thus, the SA receptors NPR1 and NPR4 play broad roles in plant immunity. 相似文献
154.
Bin Zhu Shaoying Pan Juanjuan Liu Suli Wang Ying Ni Linlin Xiao Quhao Wei You Peng Zhiyong Ding Wenli Zhao 《Cell biology international》2020,44(2):456-466
Despite the improvement in acute myeloid leukemia (AML) treatments, most patients had a poor prognosis and suffered from chemoresistance and disease relapse. Therefore, there is an urgent need for elucidation of mechanism(s) underlying drug resistance in AML. In the present study, we found that AML cells showed less susceptibility to adriamycin (ADR) in the presence of hypoxia, while inhibition of hypoxia‐inducible factor 1α (HIF‐1α) by CdCl2 can make AML cells re‐susceptibile to ADR even under hypoxia. Moreover, HIF‐1α is overexpressed and plays an important role in ADR‐resistance maintenance in resistant AML cells. We further found hypoxia or induction of HIF‐1α can significantly upregulate yes‐associated protein (YAP) expression in AML cells, and resistant cells express a high level of YAP. Finally, we found that YAP may not only enhance HIF‐1α stability but also promote HIF‐1α's activity on the target gene pyruvate kinase M2. In conclusion, our data indicate that HIF‐1α or YAP may represent a therapeutic target for overcoming resistance toward adriamycin‐based chemotherapy in AML. 相似文献
155.
Li H. X. Liu R. Q. Zhang H. M. Cao Z. X. Zhu L. X. Li Y. Y. Ding W. J. Chen Y. H. Deng Y. 《Russian Journal of Bioorganic Chemistry》2020,46(3):306-311
Russian Journal of Bioorganic Chemistry - AIDS/HIV is a serious life-threatening and public health problem that urges for new antiviral drugs to control. A bis-indole alkaloid voacamine has been... 相似文献
156.
Jingyi Ding Samantha K. Travers Manuel Delgado‐Baquerizo David J. Eldridge 《Global Change Biology》2020,26(2):709-720
Woody plant encroachment is a major land management issue. Woody removal often aims to restore the original grassy ecosystem, but few studies have assessed the role of woody removal on ecosystem functions and biodiversity at global scales. We collected data from 140 global studies and evaluated how different woody plant removal methods affected biodiversity (plant and animal diversity) and ecosystem functions (plant production, hydrological function, soil carbon) across global rangelands. Our results indicate that the impact of removal is strongly context dependent, varying with the specific response variable, removal method, and traits of the target species. Over all treatments, woody plant removal increased grass biomass and total groundstorey diversity. Physical and chemical removal methods increased grass biomass and total groundstorey biomass (i.e., non‐woody plants, including grass biomass), but burning reduced animal diversity. The impact of different treatment methods declined with time since removal, particularly for total groundstorey biomass. Removing pyramid‐shaped woody plants increased total groundstorey biomass and hydrological function but reduced total groundstorey diversity. Environmental context (e.g., aridity and soil texture) indirectly controlled the effect of removal on biomass and biodiversity by influencing plant traits such as plant shape, allelopathic, or roots types. Our study demonstrates that a one‐size‐fits‐all approach to woody plant removal is not appropriate, and that consideration of woody plant identity, removal method, and environmental context is critical for optimizing removal outcomes. Applying this knowledge is fundamental for maintaining diverse and functional rangeland ecosystems as we move toward a drier and more variable climate. 相似文献
157.
158.
159.
Shan-Shan Su Bao-Peng Li Chun-Lin Li Fang-Rui Xiu Dong-Yan Wang 《Bioscience, biotechnology, and biochemistry》2020,84(6):1123-1130
ABSTRACTThe purpose of this study was to explore the functional implication of microRNA-218 (miR-218) in diabetic nephropathy (DN) through high-glucose-stimulated renal proximal tubule impairment. Biological function experiments showed that miR-218 and inflammatory factors TNF-α and IL-1β were highly expressed in renal proximal tubule under high-glucose conditions. Inhibiting miR-218 alleviated renal tubular cell injury, which was represented by miR-218 inhibitor facilitating renal tubular cell vitality whilst reducing its apoptosis and levels of inflammation factors. In addition, we confirmed that miR-218 directly targeted GPRC5A and negatively regulated its expression. Co-transfection assay showed that overexpression of GPRC5A accentuated the mitigated action of miR-218 inhibitor on renal proximal tubule cell injury induced by high-glucose. Accordingly, these data indicated that downregulation of miR-218 can assuage high-glucose-resulted renal tubular cell damage, and its ameliorative effect was achieved by negative regulation of GPRC5A, which provides a novel direction for unearthing the pathogenesis and even further biological treatment of DN. 相似文献
160.
Guo Kaiqiang Cao Yin Li Zan Zhou Xiaoxiao Ding Rong Chen Kejing Liu Yan Qiu Yingkun Wu Zhen Fang Meijuan 《Amino acids》2020,52(5):793-809
Amino Acids - Glycine plays a key role in rapidly proliferating cancer cells such as A549 cells. Targeting glycine metabolism is considered as a potential means for cancer treatment. However, the... 相似文献