全文获取类型
收费全文 | 27064篇 |
免费 | 2860篇 |
国内免费 | 6383篇 |
出版年
2024年 | 51篇 |
2023年 | 591篇 |
2022年 | 798篇 |
2021年 | 1503篇 |
2020年 | 1182篇 |
2019年 | 1455篇 |
2018年 | 1113篇 |
2017年 | 940篇 |
2016年 | 1213篇 |
2015年 | 1683篇 |
2014年 | 2086篇 |
2013年 | 2155篇 |
2012年 | 2713篇 |
2011年 | 2341篇 |
2010年 | 1778篇 |
2009年 | 1655篇 |
2008年 | 1797篇 |
2007年 | 1634篇 |
2006年 | 1491篇 |
2005年 | 1267篇 |
2004年 | 1011篇 |
2003年 | 896篇 |
2002年 | 813篇 |
2001年 | 695篇 |
2000年 | 665篇 |
1999年 | 535篇 |
1998年 | 305篇 |
1997年 | 279篇 |
1996年 | 230篇 |
1995年 | 204篇 |
1994年 | 166篇 |
1993年 | 129篇 |
1992年 | 173篇 |
1991年 | 135篇 |
1990年 | 121篇 |
1989年 | 89篇 |
1988年 | 75篇 |
1987年 | 46篇 |
1986年 | 47篇 |
1985年 | 59篇 |
1984年 | 32篇 |
1983年 | 38篇 |
1982年 | 33篇 |
1981年 | 22篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1958年 | 4篇 |
1957年 | 7篇 |
1954年 | 4篇 |
1953年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Single Cell Transcriptome Amplification with MALBAC 总被引:1,自引:0,他引:1
2.
3.
4.
5.
6.
7.
8.
Integrated species delimitation and conservation implications of an endangered weevil Pachyrhynchus sonani (Coleoptera: Curculionidae) in Green and Orchid Islands of Taiwan 下载免费PDF全文
YEN‐TING CHEN HUI‐YUN TSENG MING‐LUEN JENG YONG‐CHAO SU WEN‐SAN HUANG CHUNG‐PING LIN 《Systematic Entomology》2017,42(4):796-813
Oceanic islands are productive habitats for generating new species and high endemism, which is primarily due to their geographical isolation, smaller population sizes and local adaptation. However, the short divergence times and subtle morphological or ecological divergence of insular organisms may obscure species identity, so the cryptic endemism on islands may be underestimated. The endangered weevil Pachyrhynchus sonani Kôno (Coleoptera: Curculionidae: Entiminae: Pachyrhynchini) is endemic to Green Island and Orchid Island of the Taiwan‐Luzon Archipelago and displays widespread variation in coloration and host range, thus raising questions regarding its species boundaries and degree of cryptic diversity. We tested the species boundaries of P. sonani using an integrated approach that combined morphological (body size and shape, genital shape, coloration and cuticular scale), genetic (four genes and restriction site‐associated DNA sequencing, RAD‐seq) and ecological (host range and distribution) diversity. The results indicated that all the morphological datasets for male P. sonani, except for the colour spectrum, reveal overlapping but statistically significant differences between islands. In contrast, the morphology of the female P. sonani showed minimum divergence between island populations. The populations of P. sonani on the two islands were significantly different in their host ranges, and the genetic clustering and phylogenies of P. sonani established two valid evolutionary species. Integrated species delimitation combining morphological, molecular and ecological characters supported two distinct species of P. sonani from Green Island and Orchid Island. The Green Island population was described as P. jitanasaius sp.n. Chen & Lin, and it is recommended that its threatened conservation status be recognized. Our findings suggest that the inter‐island speciation of endemic organisms inhabiting both islands may be more common than previously thought, and they highlight the possibility that the cryptic diversity of small oceanic islands may still be largely underestimated. 相似文献
9.
Jiefeng He Haichao Zhao Dongfeng Deng Yadong Wang Xiao Zhang Haoliang Zhao Zongquan Xu 《Journal of cellular physiology》2020,235(3):2464-2477
This study aimed to identify significant biomarkers related to the prognosis of liver cancer using long noncoding RNA (lncRNA)-associated competing endogenous RNAs (ceRNAs) analysis. Differentially expressed mRNA and lncRNAs between liver cancer and paracancerous tissues were screened, and the functions of these mRNAs were predicted by gene ontology and pathway enrichment analyses. A ceRNA network consisting of differentially expressed mRNAs and lncRNAs was constructed. LncRNA FENDRR and lncRNA HAND2-AS1 were hub nodes in the ceRNA network. A risk score assessment model consisting of eight genes (PDE2A, ESR1, FBLN5, ALDH8A1, AKR1D1, EHHADH, ADRA1A, and GNE) associated with prognosis were developed. Multivariate Cox regression suggested that both pathologic_T and risk group could be regarded as independent prognostic factors. Furthermore, a nomogram model consisting of pathologic_T and risk group showed a good prediction ability for predicting the survival rate of liver cancer patients. The nomogram model consisting of pathologic_T and a risk score assessment model could be regarded as an independent factor for predicting prognosis of liver cancer. 相似文献
10.