全文获取类型
收费全文 | 30114篇 |
免费 | 2397篇 |
国内免费 | 2029篇 |
出版年
2024年 | 52篇 |
2023年 | 381篇 |
2022年 | 844篇 |
2021年 | 1691篇 |
2020年 | 1034篇 |
2019年 | 1340篇 |
2018年 | 1280篇 |
2017年 | 928篇 |
2016年 | 1273篇 |
2015年 | 1857篇 |
2014年 | 2209篇 |
2013年 | 2476篇 |
2012年 | 2766篇 |
2011年 | 2459篇 |
2010年 | 1480篇 |
2009年 | 1276篇 |
2008年 | 1504篇 |
2007年 | 1312篇 |
2006年 | 1152篇 |
2005年 | 941篇 |
2004年 | 791篇 |
2003年 | 664篇 |
2002年 | 594篇 |
2001年 | 535篇 |
2000年 | 470篇 |
1999年 | 483篇 |
1998年 | 269篇 |
1997年 | 290篇 |
1996年 | 292篇 |
1995年 | 282篇 |
1994年 | 253篇 |
1993年 | 179篇 |
1992年 | 276篇 |
1991年 | 185篇 |
1990年 | 151篇 |
1989年 | 151篇 |
1988年 | 92篇 |
1987年 | 85篇 |
1986年 | 60篇 |
1985年 | 68篇 |
1984年 | 29篇 |
1983年 | 32篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
921.
922.
Yu-Lingzi Zhou Michael S. Caterino Dong Ren Adam Ślipiński 《Cladistics : the international journal of the Willi Hennig Society》2020,36(5):521-539
In order to place a newly discovered species Antigracilus costatus gen. sp. n. from the Lower Cretaceous Yixian Formation (China) and to assess previously unplaced fossil taxa, we investigated the relationships of extant and extinct lineages of Histeridae based on three data sets: (i) 69 morphological characters belonging to 48 taxa (representing all 11 subfamilies and 15 of 17 tribes of modern Histeridae); (ii) partitioned alignment of 6030 bp from downloaded nucleotide sequences (28S, CAD, COI, 18S) of 50 taxa (representing 10 subfamilies and 15 of 17 tribes of modern Histeridae); and (iii) a combined morphological and molecular dataset for 75 taxa. Phylogenetic analyses of the morphology and combined matrices recovered the new Lower Cretaceous taxon as a sister group to remaining Histeridae and it is placed in †Antigracilinae subfam. n. †Antigracilinae constitutes the earliest record of Histeridae from the Lower Cretaceous Yixian Formation (∼125 Myr), backdating the minimum age of the family by 25 Myr from the earliest Cenomanian (~99 Myr) to the Barremian of the Cretaceous Period. Our molecular phylogeny supports Histeridae to be divided into seven different clades, with currently recognised subfamilies Abraeinae (sensu lato), Saprininae, Chlamydopsinae, and Histerinae (sensu lato) recovered as monophyletic, while Dendrophilinae, Onthophilinae, and Tribalinae are polyphyletic taxa. The Burmese amber species †Pantostictus burmanicus Poinar & Brown is placed as a sister group to the tribe Plegaderini (Abraeinae) and was assigned as a new tribe Pantostictini trib. n. Both molecular and combined phylogenies recovered the subfamilies Trypanaeinae and Trypeticinae deeply within the subfamily Abraeinae (sensu lato), and they are downgraded into Trypanaeini stat. n. and Trypeticini stat. n. 相似文献
923.
Molecular Biology Reports - Blumeria graminis f. sp. tritici, the causal agent of wheat powdery mildew disease, can occur at all stages of the crop and constantly threatens wheat production. To... 相似文献
924.
Duan Xianlan Zhao Lian Jin Wancun Xiao Qinxin Peng Yani Huang Gan Li Xia DaSilva-Arnold Sonia Yu Haibo Zhou Zhiguang 《Molecular biology reports》2020,47(10):7557-7566
Molecular Biology Reports - The main pathogenesis of type 1 diabetes mellitus (T1DM) is autoimmune-mediated apoptosis of pancreatic islet β cells. We sought to characterize the function of... 相似文献
925.
Ji Jie Xu Min-Xue Qian Tian-Yang Zhu Sheng-Ze Jiang Feng Liu Zhao-Xiu Xu Wei-Song Zhou Juan Xiao Ming-Bing 《Molecular biology reports》2020,47(8):6091-6103
Molecular Biology Reports - Cervical cancer is the leading cause of cancer-related death among women worldwide. Identifying an effective treatment with fewer side effects is imperative, because all... 相似文献
926.
Molecular Biology Reports - Chondrocytes are the sole cell type present within cartilage, and play pivotal roles in controlling the formation and composition of health cartilage. Chondrocytes... 相似文献
927.
Li Wanting Ye Anqi Ao Luyao Zhou Lin Yan Yunyi Hu Yahui Fang Weirong Li Yunman 《Neurochemical research》2020,45(10):2258-2277
Neurochemical Research - Stroke is the fifth leading cause of death worldwide and is a main cause of disability in adults. Neither currently marketed drugs nor commonly used treatments can promote... 相似文献
928.
Qian Wang Xiao-Ping Li Xi Zhou Chun-Fen Yang Zhu Zhu 《Journal of cellular biochemistry》2020,121(10):4108-4119
This study aimed to identify the association between lnc-LAMC2-1:1 polymorphism rs2147578 and the recurrence of ovary cancer, as well as to study the underlying mechanism of rs2147578 in ovary cancer. Real-time polymerase chain reaction, Western blot analysis, immunohistochemistry, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Logrank test, and Kaplan-Meier analysis were carried out to explore the role of rs2147578 in ovary cancer. No obvious difference was observed concerning all clinical characteristics among 90 patients genotyped as CC (N = 28), CG (N = 38), and GG (N = 24) in their rs2147578 polymorphism. In addition, the subjects carrying the CC genotype had longer recurrence-free survival time and showed a lower level of malignancy compared with those carrying CG and GG genotypes. Lnc-LAMC2-1:1 and miR-128 were lowly expressed in the CC group, while deleted in colorectal cancer (DCC) was highly expressed in the CC group. Furthermore, DCC was identified as a target gene of miR-128, and miR-128 mimics decreased the luciferase activity of cells cotransfected with wild-type DCC 3′-untranslated region. Lnc-LAMC2:1-1 directly targeted and affected miR-128 expression, and the G allele in lnc-LAMC2-1:1 rs2147578 upregulated miR-128 expression. Transfection with a miR-128 precursor evidently downregulated the expression of lnc-LAMC2-1:1, miR-128, and DCC expression, but did not affect the expression of ABCC5 and body mass index. Finally, miR-128 precursor promoted cell proliferation and inhibited cell apoptosis. Compared with lnc-LAMC2-1:1 rs2147578C allele, the G allele increases the risk of ovarian cancer by reducing the binding between lnc-LAMC2-1:1 and miR-128-3p, which in turn further decreases the expression of DCC and inhibits cell apoptosis. 相似文献
929.
930.
Zhou Peilu Khan Rayyan Li Qiyao Liu Guangliang Xu Na Yang Yinju Wang Yi Wang Shusheng Chen Aiguo 《Plant Molecular Biology Reporter》2020,38(1):1-13
Plant Molecular Biology Reporter - Low temperature is among the most significant abiotic stresses restricting geographical distribution of plants and reducing crop productivity. However, the... 相似文献