全文获取类型
收费全文 | 8709篇 |
免费 | 790篇 |
国内免费 | 974篇 |
出版年
2024年 | 14篇 |
2023年 | 167篇 |
2022年 | 202篇 |
2021年 | 481篇 |
2020年 | 383篇 |
2019年 | 514篇 |
2018年 | 433篇 |
2017年 | 304篇 |
2016年 | 440篇 |
2015年 | 591篇 |
2014年 | 665篇 |
2013年 | 700篇 |
2012年 | 772篇 |
2011年 | 666篇 |
2010年 | 419篇 |
2009年 | 379篇 |
2008年 | 420篇 |
2007年 | 359篇 |
2006年 | 333篇 |
2005年 | 248篇 |
2004年 | 296篇 |
2003年 | 262篇 |
2002年 | 235篇 |
2001年 | 214篇 |
2000年 | 147篇 |
1999年 | 118篇 |
1998年 | 92篇 |
1997年 | 64篇 |
1996年 | 101篇 |
1995年 | 75篇 |
1994年 | 60篇 |
1993年 | 40篇 |
1992年 | 55篇 |
1991年 | 38篇 |
1990年 | 40篇 |
1989年 | 29篇 |
1988年 | 27篇 |
1987年 | 20篇 |
1986年 | 16篇 |
1985年 | 23篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1979年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Yang Su-Rong Sun Huan-Xin Hu Zhen-Zhen Wang Si-Heng Sun Hui Xue Yin-Jia Ye Chen-Bo 《Sleep and biological rhythms》2017,15(1):57-65
Sleep and Biological Rhythms - Chronic sleep deprivation (SD) is an overwhelming problem in young students. Firstly, we investigated whether different levels of pre-training SD had effects on... 相似文献
3.
4.
5.
Yan Xue Liu Jia Wu Ke-Xin Yang Nan Pan Li-Ben Song Ying Liu Yang Tang Zhong-Hua 《Journal of Plant Growth Regulation》2022,41(6):2421-2434
Journal of Plant Growth Regulation - Early-spring plants are a special type of plant that complete their life cycle promptly in cold, early spring. Very little effort has been made into researching... 相似文献
6.
Genome‐wide detection of CNVs associated with beak deformity in chickens using high‐density 600K SNP arrays 下载免费PDF全文
H. Bai Y. Sun N. Liu Y. Liu F. Xue Y. Li S. Xu A. Ni J. Ye Y. Chen J. Chen 《Animal genetics》2018,49(3):226-236
Beak deformity (crossed beaks) is found in several indigenous chicken breeds including Beijing‐You studied here. Birds with deformed beaks have reduced feed intake and poor production performance. Recently, copy number variation (CNV) has been examined in many species and is recognized as a source of genetic variation, especially for disease phenotypes. In this study, to unravel the genetic mechanisms underlying beak deformity, we performed genome‐wide CNV detection using Affymetrix chicken high‐density 600K data on 48 deformed‐beak and 48 normal birds using penncnv . As a result, two and eight CNV regions (CNVRs) covering 0.32 and 2.45 Mb respectively on autosomes were identified in deformed‐beak and normal birds respectively. Further RT‐qPCR studies validated nine of the 10 CNVRs. The ratios of six CNVRs were significantly different between deformed‐beak and normal birds (P < 0.01). Within these six regions, three and 21 known genes were identified in deformed‐beak and normal birds respectively. Bioinformatics analysis showed that these genes were enriched in six GO terms and one KEGG pathway. Five candidate genes in the CNVRs were further validated using RT‐qPCR. The expression of LRIG2 (leucine rich repeats and immunoglobulin like domains 2) was lower in birds with deformed beaks (P < 0.01). Therefore, the LRIG2 gene could be considered a key factor in view of its known functions and its potential roles in beak deformity. Overall, our results will be helpful for future investigations of the genomic structural variations underlying beak deformity in chickens. 相似文献
7.
Social responsibility links personal behavior with societal expectations and plays a key role in affecting an agent’s emotional state following a decision. However, the neural basis of responsibility attribution remains unclear. In two previous event-related brain potential (ERP) studies we found that personal responsibility modulated outcome evaluation in gambling tasks. Here we conducted a functional magnetic resonance imaging (fMRI) study to identify particular brain regions that mediate responsibility attribution. In a context involving team cooperation, participants completed a task with their teammates and on each trial received feedback about team success and individual success sequentially. We found that brain activity differed between conditions involving team success vs. team failure. Further, different brain regions were associated with reinforcement of behavior by social praise vs. monetary reward. Specifically, right temporoparietal junction (RTPJ) was associated with social pride whereas dorsal striatum and dorsal anterior cingulate cortex (ACC) were related to reinforcement of behaviors leading to personal gain. The present study provides evidence that the RTPJ is an important region for determining whether self-generated behaviors are deserving of praise in a social context. 相似文献
8.
9.
10.
石刁柏已形成细胞的幼嫩胚乳,接种在附加有不同浓度的生长素(NAA)和细胞分裂素(BA)的 MS 培养基上,获得了愈伤组织。愈伤组织的诱导频率随生长素的浓度不同而异,可达65.9—83.1%。将胚乳愈伤组织转移到降低了生长素浓度或只含有低浓度生长素的分化培养基上,可陆续分化芽、根、芽丛和少量胚状体,个别的芽和胚状体能发育成小植株。切取1.5—5cm 长的芽,接种在诱导根的培养基上,或在 IBA50ppm 溶液中浸泡2小时,转移到 MS 基本培养基上,部分芽能生根形成完整植株。 相似文献