全文获取类型
收费全文 | 6329篇 |
免费 | 438篇 |
国内免费 | 1篇 |
出版年
2024年 | 6篇 |
2023年 | 26篇 |
2022年 | 89篇 |
2021年 | 135篇 |
2020年 | 97篇 |
2019年 | 149篇 |
2018年 | 193篇 |
2017年 | 138篇 |
2016年 | 248篇 |
2015年 | 355篇 |
2014年 | 410篇 |
2013年 | 485篇 |
2012年 | 634篇 |
2011年 | 535篇 |
2010年 | 390篇 |
2009年 | 321篇 |
2008年 | 450篇 |
2007年 | 424篇 |
2006年 | 340篇 |
2005年 | 297篇 |
2004年 | 311篇 |
2003年 | 244篇 |
2002年 | 184篇 |
2001年 | 50篇 |
2000年 | 44篇 |
1999年 | 47篇 |
1998年 | 41篇 |
1997年 | 18篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1980年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1965年 | 2篇 |
排序方式: 共有6768条查询结果,搜索用时 31 毫秒
111.
BackgroundWe investigated the relationship between genetic alterations and 18F-FDG PET/CT findings in head and neck squamous cell carcinoma (HNSC).MethodsUsing mRNA-sequences of HNSC samples (480 patients) from the Cancer Genome Atlas (TCGA) portal, gene coexpression networks were constructed via a weighted correlation network analysis (WGCNA) algorithm, and their association with the tumor-to-blood signal ratio on 18F-FDG PET/CT data (21 patients) was explored. An elastic-net regression model was developed to estimate the PET tumor-to-blood ratio from the gene networks and to derive an FDG signature score (FDGSS). The FDGSS was evaluated with regard to clinical variables and general mutational profiles, as well as alterations to oncogenic signaling pathways.FindingsThe FDGSS values differed across clinical stages (p = 0.027), HPV-status (p< 0.001), and molecular subtypes of HNSC (p< 0.001). Multivariate Cox regression demonstrated that FDGSS was an independent predictor for overall (p = 0.019) and progression-free survival (p = 0.024). FDGSS positively correlated with total mutation rate (p = 0.016), aneuploidy (p < 0.001), and somatic copy number alteration scores (p < 0.001). CDKN2A in the cell cycle pathway (q = 0.014) and the TP53 gene in the TP53 pathway (q = 0.005) showed significant differences between high and low FDGSS patients.ConclusionFDGSS based on the gene coexpression network was associated with the mutational landscape of HNSC. 18F-FDG PET/CT is therefore a valuable tool for the in vivo imaging of these cancers, being able to visualize the glucose metabolism of the tumor and allow inferences to be made on the underlying genetic alterations in the tumor. 相似文献
112.
113.
Min-Young Song Chi-Yeol Kim Muho Han Hak-Seung Ryu Sang-Kyu Lee Li Sun Zuhua He Young-Su Seo Patrick Canal Pamela C. Ronald Jong-Seong Jeon 《Molecules and cells》2013,35(4):327-334
The required for Mla12 resistance (RAR1) protein is essential for the plant immune response. In rice, a model monocot species, the function of Oryza sativa RAR1 (OsRAR1) has been little explored. In our current study, we characterized the response of a rice osrar1 T-DNA insertion mutant to infection by Magnaporthe oryzae, the causal agent of rice blast disease. osrar1 mutants displayed reduced resistance compared with wild type rice when inoculated with the normally virulent M. oryzae isolate PO6-6, indicating that OsRAR1 is required for an immune response to this pathogen. We also investigated the function of OsRAR1 in the resistance mechanism mediated by the immune receptor genes Pib and Pi5 that encode nucleotide binding-leucine rich repeat (NB-LRR) proteins. We inoculated progeny from Pib/osrar1 and Pi5/osrar1 heterozygous plants with the avirulent M. oryzae isolates, race 007 and PO6-6, respectively. We found that only Pib-mediated resistance was compromised by the osrar1 mutation and that the introduction of the OsRAR1 cDNA into Pib/osrar1 rescued Pib-mediated resistance. These results indicate that OsRAR1 is required for Pib-mediated resistance but not Pi5-mediated resistance to M. oryzae. 相似文献
114.
115.
Na Na Kim Hyun Suk Shin Young Jae Choi Yuzo Yamamoto Kosuke Fukaya Hiroshi Ueda 《Marine and Freshwater Behaviour and Physiology》2013,45(6):397-410
Migrating fish such as salmonids are affected by external environmental factors and salinity changes are particularly important, influencing spawning migration. The aim of this study was to test whether changes in salinity would affect the expression of the hypothalamic-pituitary-gonadal (HPG) axis hormones (gonadotropin-releasing hormones (GnRHs) [salmon GnRH and chicken GnRH-II], GnRH receptors [GnRHR1 and GnRHR5], and mRNA of the gonadotropin hormone [GTH] subunits [GTHα, follicle stimulating hormone β, and luteinizing hormone β]) in chum salmon (Oncorhynchus keta). Fish were progressively transferred from seawater (SW) through 50% SW to freshwater (FW), and the relationship between the osmoregulatory hormone prolactin (PRL) and sexual maturation was determined. The expression and activity of HPG hormones and their receptors, and levels of estradiol-17β and PRL increased after fish were transferred to FW, demonstrating that changes in salinity stimulate the HPG axis and PRL production in migrating chum salmon. These findings reveal details about the role of the endocrine system in maintaining homeostasis and stimulating sexual maturation and reproduction in response to salinity changes in this species. 相似文献
116.
Insu Jeon Ji-Yong Bae Jin-Hong Park Taek-Rim Yoon Mitsugu Todo Masaaki Mawatari 《Computer methods in biomechanics and biomedical engineering》2013,16(1):103-112
To investigate the biomechanical effect of collars, finite element analyses are carried out through two hip joints that are implanted using collared and collarless stems, respectively, and an intact hip joint model. For the analyses, the sacrum, coxal bone, and the cancellous and cortical bones of a femur are modelled using finite elements based on X-ray computed tomographic images taken from a 27-year-old woman. From the results, it is found that a collar with perfect calcar contact prevents stem subsidence and decreases the proximal–lateral gap and the lateral stem tilting. Therefore, it can impart reasonable biomechanical stability for total hip arthroplasty. However, its low load transmission ability and increased stem tilting effect due to the imperfect contact between the collar and the calcar are found to be serious problems that need to be solved. Results of clinical follow-up are presented for supporting the computational results. 相似文献
117.
118.
119.
Byoung-Shik Shim Jung-ah Choi Ho-Hyun Song Sung-Moo Park In Su Cheon Ji-Eun Jang Sun Je Woo Chung Hwan Cho Min-Suk Song Hyemi Kim Kyung Joo Song Jae Myun Lee Suhng Wook Kim Dae Sub Song Young Ki Choi Jae-Ouk Kim Huan Huu Nguyen Dong Wook Kim Young Yil Bahk Cheol-Heui Yun Man Ki Song 《Journal of microbiology (Seoul, Korea)》2013,51(1):130-135
Influenza viruses are respiratory pathogens that continue to pose a significantly high risk of morbidity and mortality of humans worldwide. Vaccination is one of the most effective strategies for minimizing damages by influenza outbreaks. In addition, rapid development and production of efficient vaccine with convenient administration is required in case of influenza pandemic. In this study, we generated recombinant influenza virus hemagglutinin protein 1 (sHA1) of 2009 pandemic influenza virus as a vaccine candidate using a well-established bacterial expression system and administered it into mice via sublingual (s.l.) route. We found that s.l. immunization with the recombinant sHA1 plus cholera toxin (CT) induced mucosal antibodies as well as systemic antibodies including neutralizing Abs and provided complete protection against infection with pandemic influenza virus A/CA/04/09 (H1N1) in mice. Indeed, the protection efficacy was comparable with that induced by intramuscular (i.m.) immunization route utilized as general administration route of influenza vaccine. These results suggest that s.l. vaccination with the recombinant non-glycosylated HA1 protein offers an alternative strategy to control influenza outbreaks including pandemics. 相似文献
120.
Three, six, nine, and twelve V of electric pulse (EP) was applied to a culture of Weissella cibaria SKkimchi1 in MRS medium and kimchi-making culture (KMC). Viable cell number of SKkimchi1 in MRS medium was decreased in proportion to pulse intensity but that of bacteria in KMC was not. Lactic acid and ethanol produced by SKkimchi1 tended to be decreased in proportion to EP intensity but acetic acid was proportionally increased to EP intensity. Lactic acid, ethanol, and propionic acid produced in KMC were proportionally decreased, but acetic acid was proportionally increased to the EP intensity. Bacterial community and diversity in KMC were analyzed based on culture time by a temperature gradient gel electrophoresis (TGGE) technique. Most bacterial communities grown in freshly prepared kimchi belonged to Bacillus genus. Lactic acid bacteria responsible for kimchi fermentation began to grow on day 4, and were completely substituted for Bacillus genus on day 8, but some Bacillus genus began to grow again on day 12. However, bacterial community diversities were not different based on varying EP intensity. 相似文献