全文获取类型
收费全文 | 4502篇 |
免费 | 288篇 |
国内免费 | 13篇 |
出版年
2023年 | 36篇 |
2022年 | 70篇 |
2021年 | 237篇 |
2020年 | 123篇 |
2019年 | 133篇 |
2018年 | 151篇 |
2017年 | 145篇 |
2016年 | 184篇 |
2015年 | 245篇 |
2014年 | 287篇 |
2013年 | 381篇 |
2012年 | 348篇 |
2011年 | 321篇 |
2010年 | 232篇 |
2009年 | 201篇 |
2008年 | 204篇 |
2007年 | 199篇 |
2006年 | 158篇 |
2005年 | 128篇 |
2004年 | 122篇 |
2003年 | 112篇 |
2002年 | 110篇 |
2001年 | 66篇 |
2000年 | 67篇 |
1999年 | 52篇 |
1998年 | 16篇 |
1997年 | 28篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 14篇 |
1993年 | 22篇 |
1992年 | 36篇 |
1991年 | 23篇 |
1990年 | 21篇 |
1989年 | 17篇 |
1988年 | 27篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 17篇 |
1984年 | 27篇 |
1983年 | 15篇 |
1982年 | 20篇 |
1980年 | 11篇 |
1978年 | 12篇 |
1976年 | 8篇 |
1974年 | 10篇 |
1973年 | 10篇 |
1971年 | 9篇 |
1969年 | 7篇 |
1967年 | 9篇 |
排序方式: 共有4803条查询结果,搜索用时 15 毫秒
91.
Qadir Sami Ullah Raja Vaseem Siddiqui Weqar A. Alyemeni Mohammed Nasser Ahmad Parvaiz 《Journal of Plant Growth Regulation》2021,40(4):1450-1465
Journal of Plant Growth Regulation - Increased dependence on thermal power has resulted in a significant increase in the generation of fly ash (FA), which exacerbates environmental... 相似文献
92.
Zhanhuai Wang Lindsay M. Hopson Stephanie S. Singleton Xiaochun Yang Wilma Jogunoori Raja Mazumder Vincent Obias Paul Lin Bao-Ngoc Nguyen Michael Yao Larry Miller Jon White Shuyun Rao Lopa Mishra 《生物化学与生物物理学报:疾病的分子基础》2021,1867(10):166179
Emerging data show a rise in colorectal cancer (CRC) incidence in young men and women that is often chemoresistant. One potential risk factor is an alteration in the microbiome. Here, we investigated the role of TGF-β signaling on the intestinal microbiome and the efficacy of chemotherapy for CRC induced by azoxymethane and dextran sodium sulfate in mice. We used two genotypes of TGF-β-signaling-deficient mice (Smad4+/? and Smad4+/?Sptbn1+/?), which developed CRC with similar phenotypes and had similar alterations in the intestinal microbiome. Using these mice, we evaluated the intestinal microbiome and determined the effect of dysfunctional TGF-β signaling on the response to the chemotherapeutic agent 5-Fluoro-uracil (5FU) after induction of CRC. Using shotgun metagenomic sequencing, we determined gut microbiota composition in mice with CRC and found reduced amounts of beneficial species of Bacteroides and Parabacteroides in the mutants compared to the wild-type (WT) mice. Furthermore, the mutant mice with CRC were resistant to 5FU. Whereas the abundances of E. boltae, B.dorei, Lachnoclostridium sp., and Mordavella sp. were significantly reduced in mice with CRC, these species only recovered to basal amounts after 5FU treatment in WT mice, suggesting that the alterations in the intestinal microbiome resulting from compromised TGF-β signaling impaired the response to 5FU. These findings could have implications for inhibiting the TGF-β pathway in the treatment of CRC or other cancers. 相似文献
93.
94.
Jennifer C. Erasmus Kasia Smolarczyk Helena Brezovjakova Noor F. Mohd-Naim Encarnacin Lozano Karl Matter Vania M.M. Braga 《The Journal of cell biology》2021,220(6)
Rac1 GTPase is hyperactivated in tumors and contributes to malignancy. Rac1 disruption of junctions requires its effector PAK1, but the precise mechanisms are unknown. Here, we show that E-cadherin is internalized via micropinocytosis in a PAK1–dependent manner without catenin dissociation and degradation. In addition to internalization, PAK1 regulates E-cadherin transport by fine-tuning Rab small GTPase function. PAK1 phosphorylates a core Rab regulator, RabGDIβ, but not RabGDIα. Phosphorylated RabGDIβ preferentially associates with Rab5 and Rab11, which is predicted to promote Rab retrieval from membranes. Consistent with this hypothesis, Rab11 is activated by Rac1, and inhibition of Rab11 function partially rescues E-cadherin destabilization. Thus, Rac1 activation reduces surface cadherin levels as a net result of higher bulk flow of membrane uptake that counteracts Rab11-dependent E-cadherin delivery to junctions (recycling and/or exocytosis). This unique small GTPase crosstalk has an impact on Rac1 and PAK1 regulation of membrane remodeling during epithelial dedifferentiation, adhesion, and motility. 相似文献
95.
Khan Md. Idrish Raja Kamilya Dibyendu Choudhury Tanmoy Gon Tripathy Partha Sarathi Rathore Gaurav 《Probiotics and antimicrobial proteins》2021,13(6):1572-1584
Probiotics and Antimicrobial Proteins - In this study, a bacterial strain COFCAU_P1, isolated from the digestive tract of a freshwater teleost rohu (Labeo rohita), was identified as Bacillus... 相似文献
96.
BS Sabna Thankappan Bency Mahendran Ramasamy Muthusamy Gayathri Femil selta Daniel Raja Angayarkanni Jayaraman 《Probiotics and antimicrobial proteins》2021,13(4):993-1004
Probiotics and Antimicrobial Proteins - Gamma-aminobutyric acid (GABA) is a principal inhibitory neurotransmitter in the central nervous system and is produced by irreversible decarboxylation of... 相似文献
97.
Chorong Park Chen Peng M. Julhasur Rahman Sherry L. Haller Loubna Tazi Greg Brennan Stefan Rothenburg 《PLoS pathogens》2021,17(1)
The antiviral protein kinase R (PKR) is an important host restriction factor, which poxviruses must overcome to productively infect host cells. To inhibit PKR, many poxviruses encode a pseudosubstrate mimic of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2), designated K3 in vaccinia virus. Although the interaction between PKR and eIF2α is highly conserved, some K3 orthologs from host-restricted poxviruses were previously shown to inhibit PKR in a species-specific manner. To better define this host range function, we compared the sensitivity of PKR from 17 mammals to inhibition by K3 orthologs from closely related orthopoxviruses, a genus with a generally broader host range. The K3 orthologs showed species-specific inhibition of PKR and exhibited three distinct inhibition profiles. In some cases, PKR from closely related species showed dramatic differences in their sensitivity to K3 orthologs. Vaccinia virus expressing the camelpox virus K3 ortholog replicated more than three orders of magnitude better in human and sheep cells than a virus expressing vaccinia virus K3, but both viruses replicated comparably well in cow cells. Strikingly, in site-directed mutagenesis experiments between the variola virus and camelpox virus K3 orthologs, we found that different amino acid combinations were necessary to mediate improved or diminished inhibition of PKR derived from different host species. Because there is likely a limited number of possible variations in PKR that affect K3-interactions but still maintain PKR/eIF2α interactions, it is possible that by chance PKR from some potential new hosts may be susceptible to K3-mediated inhibition from a virus it has never previously encountered. We conclude that neither the sensitivity of host proteins to virus inhibition nor the effectiveness of viral immune antagonists can be inferred from their phylogenetic relatedness but must be experimentally determined. 相似文献
98.
Bindu S. Mayi Jillian A. Leibowitz Arden T. Woods Katherine A. Ammon Alphonse E. Liu Aarti Raja 《PLoS pathogens》2021,17(1)
Neuropilin-1 (NRP-1), a member of a family of signaling proteins, was shown to serve as an entry factor and potentiate SARS Coronavirus 2 (SARS-CoV-2) infectivity in vitro. This cell surface receptor with its disseminated expression is important in angiogenesis, tumor progression, viral entry, axonal guidance, and immune function. NRP-1 is implicated in several aspects of a SARS-CoV-2 infection including possible spread through the olfactory bulb and into the central nervous system and increased NRP-1 RNA expression in lungs of severe Coronavirus Disease 2019 (COVID-19). Up-regulation of NRP-1 protein in diabetic kidney cells hint at its importance in a population at risk of severe COVID-19. Involvement of NRP-1 in immune function is compelling, given the role of an exaggerated immune response in disease severity and deaths due to COVID-19. NRP-1 has been suggested to be an immune checkpoint of T cell memory. It is unknown whether involvement and up-regulation of NRP-1 in COVID-19 may translate into disease outcome and long-term consequences, including possible immune dysfunction. It is prudent to further research NRP-1 and its possibility of serving as a therapeutic target in SARS-CoV-2 infections. We anticipate that widespread expression, abundance in the respiratory and olfactory epithelium, and the functionalities of NRP-1 factor into the multiple systemic effects of COVID-19 and challenges we face in management of disease and potential long-term sequelae. 相似文献
99.
Rahman Md. Mokhlesur Jahan Hawa Rabbe Md. Fazle Chakraborty Moumita Salauddin Md. 《EcoHealth》2021,18(1):31-43
EcoHealth - Global amphibian populations are facing a novel threat, chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), which is responsible for the severe decline of a... 相似文献
100.
Farhan Haq Salmaan Sharif Adnan Khurshid Aamer Ikram Imran Shabbir Muhammad Salman Abdul Ahad Muhammad Suleman Rana Aroosha Raja Nazish Badar Hanaa Tashkandi Turki Al Amri Esam I. Azhar Mohammed S. Almuhayawi Steve Harakeh Muhammad Faraz Arshad Malik 《Saudi Journal of Biological Sciences》2021,28(1):942