全文获取类型
收费全文 | 58161篇 |
免费 | 4352篇 |
国内免费 | 26篇 |
专业分类
62539篇 |
出版年
2023年 | 232篇 |
2022年 | 723篇 |
2021年 | 1226篇 |
2020年 | 723篇 |
2019年 | 898篇 |
2018年 | 1283篇 |
2017年 | 1124篇 |
2016年 | 1796篇 |
2015年 | 2926篇 |
2014年 | 3267篇 |
2013年 | 3658篇 |
2012年 | 4851篇 |
2011年 | 4669篇 |
2010年 | 2933篇 |
2009年 | 2682篇 |
2008年 | 3684篇 |
2007年 | 3529篇 |
2006年 | 3057篇 |
2005年 | 2846篇 |
2004年 | 2647篇 |
2003年 | 2365篇 |
2002年 | 2052篇 |
2001年 | 1381篇 |
2000年 | 1277篇 |
1999年 | 1073篇 |
1998年 | 507篇 |
1997年 | 397篇 |
1996年 | 309篇 |
1995年 | 273篇 |
1994年 | 263篇 |
1993年 | 227篇 |
1992年 | 380篇 |
1991年 | 354篇 |
1990年 | 309篇 |
1989年 | 267篇 |
1988年 | 208篇 |
1987年 | 194篇 |
1986年 | 169篇 |
1985年 | 167篇 |
1984年 | 125篇 |
1983年 | 136篇 |
1982年 | 108篇 |
1981年 | 95篇 |
1980年 | 90篇 |
1979年 | 103篇 |
1978年 | 86篇 |
1977年 | 84篇 |
1975年 | 70篇 |
1974年 | 99篇 |
1973年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
132.
133.
134.
135.
136.
QuangMinh Nguyen Arya Bagus Boedi Iswanto Geon Hui Son Uyen Thi Vuong Jihyun Lee JinHo Kang Walter Gassmann Sang Hee Kim 《Molecular Plant Pathology》2022,23(9):1390
During pathogenesis, effector proteins are secreted from the pathogen to the host plant to provide virulence activity for invasion of the host. However, once the host plant recognizes one of the delivered effectors, effector‐triggered immunity activates a robust immune and hypersensitive response (HR). In planta, the effector AvrRps4 is processed into the N‐terminus (AvrRps4N) and the C‐terminus (AvrRps4C). AvrRps4C is sufficient to trigger HR in turnip and activate AtRRS1/AtRPS4‐mediated immunity in Arabidopsis; on the other hand, AvrRps4N induces HR in lettuce. Furthermore, AvrRps4N‐mediated HR requires a conserved arginine at position 112 (R112), which is also important for full‐length AvrRps4 (AvrRps4F) processing. Here, we show that effector processing and effector recognition in lettuce are uncoupled for the AvrRps4 family. In addition, we compared effector recognition by lettuce of AvrRps4 and its homologues, HopK1 and XopO. Interestingly, unlike for AvrRps4 and HopK1, mutation of the conserved R111 in XopO by itself was insufficient to abolish recognition. The combination of amino acid substitutions arginine 111 to leucine with glutamate 114 to lysine abolished the XopO‐mediated HR, suggesting that AvrRps4 family members have distinct structural requirements for perception by lettuce. Together, our results provide an insight into the processing and recognition of AvrRps4 and its homologues. 相似文献
137.
138.
139.
Nicholas G Economos Elias Quijano Kelly E W Carufe J
Dinithi
R Perera Peter
M Glazer 《Nucleic acids research》2022,50(10):e59
Despite the rapid and broad implementation of CRISPR-Cas9-based technologies, convenient tools to modulate dose, timing, and precision remain limited. Building on methods using synthetic peptide nucleic acids (PNAs) to bind RNA with unusually high affinity, we describe guide RNA (gRNA) spacer-targeted, or ‘antispacer’, PNAs as a tool to modulate Cas9 binding and activity in cells in a sequence-specific manner. We demonstrate that PNAs rapidly and efficiently target complexed gRNA spacer sequences at low doses and without design restriction for sequence-selective Cas9 inhibition. We further show that short PAM-proximal antispacer PNAs achieve potent cleavage inhibition (over 2000-fold reduction) and that PAM-distal PNAs modify gRNA affinity to promote on-target specificity. Finally, we apply antispacer PNAs for temporal regulation of two dCas9-fusion systems. These results present a novel rational approach to nucleoprotein engineering and describe a rapidly implementable antisense platform for CRISPR-Cas9 modulation to improve spatiotemporal versatility and safety across applications. 相似文献
140.
Sierra Phillips Megan Lameka Christopher Beaumont Nileshkumar Chaudhari Jared Halstrom James Rush Jones Nicholas A. Andrews Ashish Shah 《The Iowa orthopaedic journal》2022,42(1):207
BackgroundIntra-articular injections are a standard therapy and diagnostic tool for a variety of wrist conditions. Accurate needle placement is crucial for proper therapeutic benefit and prevention of complications. While some studies claim accurate needle placement requires imaging, others conclude that anatomical guidance is sufficient. This study aimed to evaluate the accuracy of intra-articular wrist needle placement with the ulnocarpal approach across differing levels of training using clinical anatomy alone.MethodsFourteen fresh-frozen, above-elbow cadaveric specimens were used. Intra-articular needle placement into the wrist via an ulnocarpal approach was attempted by nine study participants: two interns, two junior-level residents, two senior-level residents, two hand fellows, and one attending hand surgeon. Each injection was performed based on clinical examination and landmarks alone. The number of attempts and total time taken for each injection was recorded.ResultsOverall success rate was 71%, (89 of 126 attempts) and did not vary significantly across levels of training. Average time for needle placement among all participants was 10.9 ± 6.5 seconds. Timing of successful intra-articular needle placement (10.4 ± 5.2 seconds) significantly differed between levels. However, timing did not trend in any direction with more or less training. No significant difference was noted in total attempts or attempts with successful outcomes when comparing level of training.ConclusionThe ulnocarpal approach is a viable option for injection or aspiration of the wrist without image guidance. We were unable to show any relevant trends with timing or number of attempts in comparison to level of training. Level of Evidence: V 相似文献