全文获取类型
收费全文 | 46679篇 |
免费 | 3404篇 |
国内免费 | 19篇 |
出版年
2023年 | 145篇 |
2022年 | 124篇 |
2021年 | 785篇 |
2020年 | 568篇 |
2019年 | 682篇 |
2018年 | 1027篇 |
2017年 | 906篇 |
2016年 | 1477篇 |
2015年 | 2322篇 |
2014年 | 2666篇 |
2013年 | 2980篇 |
2012年 | 3940篇 |
2011年 | 3780篇 |
2010年 | 2395篇 |
2009年 | 2189篇 |
2008年 | 3037篇 |
2007年 | 2913篇 |
2006年 | 2547篇 |
2005年 | 2361篇 |
2004年 | 2161篇 |
2003年 | 1865篇 |
2002年 | 1613篇 |
2001年 | 1299篇 |
2000年 | 1226篇 |
1999年 | 982篇 |
1998年 | 376篇 |
1997年 | 322篇 |
1996年 | 228篇 |
1995年 | 209篇 |
1994年 | 207篇 |
1993年 | 172篇 |
1992年 | 326篇 |
1991年 | 295篇 |
1990年 | 266篇 |
1989年 | 226篇 |
1988年 | 173篇 |
1987年 | 163篇 |
1986年 | 131篇 |
1985年 | 105篇 |
1984年 | 77篇 |
1983年 | 84篇 |
1982年 | 63篇 |
1981年 | 53篇 |
1980年 | 54篇 |
1979年 | 69篇 |
1978年 | 51篇 |
1977年 | 50篇 |
1976年 | 43篇 |
1975年 | 42篇 |
1974年 | 63篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Sun Jin Kim Samuel T. Hatch Andrew S. Dixon Shawn C. Owen 《Biotechnology and bioengineering》2019,116(7):1575-1583
Expressing, isolating, and characterizing recombinant proteins is crucial to many disciplines within the biological sciences. Different molecular tagging technologies have been developed to enable each individual step of protein production, from expression through purification and characterization. Monitoring the entire production process requires multiple tags or molecular interactions, because no individual tag has provided the comprehensive breadth of utility. An ideal molecular tag is small and does not interrupt expression, solubility, folding or function of the protein being purified and can be used throughout the production process. We adapted and integrated a split-luciferase system (NanoBiT®, Promega ®) to perform the range of techniques essential to protein production. We developed a simple method to monitor protein expression in real time to optimize expression conditions. We constructed a novel affinity chromatography system using the split-luciferase system to enable purification. We adapted western blot analysis, enzyme-linked immunosorbent assay, and cell-based bioassay to characterize the expressed proteins. Our results demonstrate that a single-tag can fulfill all aspects needed throughout protein production. 相似文献
992.
Chae Rin Park Won Jong Rhee Kyu Won Kim Byeong Hee Hwang 《Biotechnology and bioengineering》2019,116(7):1567-1574
On-site genetic detection needs to develop a sensitive and straightforward biosensor without special equipment, which can detect various genetic biomarkers. Hybridization chain reaction (HCR) amplifying signal isothermally could be considered as a good candidate for on-site detection. Here, we developed a novel genetic biosensor on the basis of enzyme-free dual-amplification of universal hybridization chain reaction (uHCR) and hemin/G-quadruplex horseradish peroxidase (HRP)-mimicking DNAzyme. The uHCR is the strategy which enables simple design for multiple target detection by the introduction of target-specific trigger hairpin without changing the whole system according to a target change. Also, HRP-mimicking DNAzyme could produce a sensitive and quantitative colorimetric signal with increased stability with a limit of detection (LOD) of 5.67 nM. The universality of the uHCR biosensor was proven by the detection of four different targets (miR-21, miR-125b, KRAS-Q61K, and BRAF-V600E) for cancer diagnosis. The uHCR biosensor showed specificity that could discriminate single-nucleotide polymorphism. Moreover, the uHCR biosensor could detect targets in the diluted serum sample. Overall, the uHCR biosensor demonstrated the potential for field testing with a simple redesign without complicated steps or special equipment using a universal hairpin system and enzyme-free amplification. This strategy could enable stable and sensitive detection of a variety of targets. Therefore, it could be applied to urgent detection of various pathogens, remote diagnosis, and self-screening of diseases. 相似文献
993.
Kim M. Keppler-Noreuil Julie C. Sapp Marjorie J. Lindhurst Thomas N. Darling Jasmine Burton-Akright Mohammadhadi Bagheri Eva Dombi Ashlyn Gruber Paul F. Jarosinski Staci Martin Neera Nathan Scott M. Paul Ronald E. Savage Pamela L. Wolters Brian Schwartz Brigitte C. Widemann Leslie G. Biesecker 《American journal of human genetics》2019,104(3):484-491
994.
995.
Yeongseon Park Yuseob Kim 《Evolution; international journal of organic evolution》2019,73(8):1564-1577
Temporally varying selection is known to maintain genetic polymorphism under certain restricted conditions. However, if part of a population can escape from selective pressure, a condition called the “storage effect” is produced, which greatly promotes balanced polymorphism. We investigate whether seasonally fluctuating selection can maintain polymorphism at multiple loci, if cyclically fluctuating selection is not acting on a subpopulation called a “refuge.” A phenotype with a seasonally oscillating optimum is determined by alleles at multiple sites, across which the effects of mutations on phenotype are distributed randomly. This model resulted in long‐term polymorphism at multiple sites, during which allele frequencies oscillate heavily, greatly increasing the level of nonneutral polymorphism. The level of polymorphism at linked neutral sites was either higher or lower than expected for unlinked neutral loci. Overall, these results suggest that for a protein‐coding sequence, the nonsynonymous‐to‐synonymous ratio of polymorphism may exceed one. In addition, under randomly perturbed environmental oscillation, different sets of sites may take turns harboring long‐term polymorphism, thus making trans‐species polymorphism (which has been predicted as a classical signature of balancing selection) less likely. 相似文献
996.
Moccetti Paolo Siwertsson Anna Kjær Runar Amundsen Per-Arne Præbel Kim Tamayo Ana-Maria Peris Power Michael Knudsen Rune 《Hydrobiologia》2019,829(1):281-290
Hydrobiologia - Lipid biomarkers in sediments, which are indicative of biological production, provide important information regarding the environmental conditions in and around lakes, and can be... 相似文献
997.
Lee Jun-Won Oh Ji Eun Rhee Ki-Jong Yoo Byung-Su Eom Young Woo Park Sang Wook Lee Ji Hyun Son Jung-Woo Youn Young Jin Ahn Min-Soo Ahn Sung-Gyun Kim Jang-Young Lee Seung-Hwan Yoon Junghan 《Molecular and cellular biochemistry》2019,453(1-2):197-203
Molecular and Cellular Biochemistry - Electron transfer occurs through heme-Fe across the cytochrome c protein. The current models of long range electron transfer pathways in proteins include... 相似文献
998.
Chung Hyung-Joo Kim Muwoong Jung Junyang Jeong Na Young 《Neurochemical research》2019,44(8):1964-1976
Neurochemical Research - Schwann cells are essential glial cells in the peripheral nervous system (PNS), and dysfunction of Schwann cells can induce various peripheral neurodegenerative diseases.... 相似文献
999.
1000.
Eun Hye Lee Jin Hak Shin Seon Sook Kim Hanbyeol Lee Se-Ran Yang Su Ryeon Seo 《Journal of cellular physiology》2019,234(5):6854-6864
Laurus nobilis Linn. (Lauraceae), commonly known as Bay, has been used as a traditional medicine in the Mediterranean and Europe to treat diverse immunological disorders. Although the effects of L. nobilis on immunosuppression have been reported, the detailed underlying mechanism remains unclear. In this study, to elucidate the anti-inflammatory mechanism of L. nobilis, we examined the effect of L. nobilis leaf extract on inflammasome activation in mouse bone marrow-derived macrophages. L. nobilis leaf extract inhibited NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome activation, which was associated with caspase-1 activation, interleukin-1β secretion, and apoptosis-associated speck-like protein containing a CARD (ASC) pyroptosome complex formation. We also observed that 1,8-cineole, the major component of L. nobilis extract, consistently suppressed NLRP3 inflammasome activation. Furthermore, L. nobilis leaf extract attenuated the in vivo expression of proinflammatory cytokines in an acute lung injury mouse model. Our results provide the first evidence that L. nobilis leaf extract modulates inflammatory signaling by suppressing inflammasome activation. 相似文献