全文获取类型
收费全文 | 9674篇 |
免费 | 927篇 |
国内免费 | 1236篇 |
出版年
2024年 | 42篇 |
2023年 | 196篇 |
2022年 | 428篇 |
2021年 | 696篇 |
2020年 | 519篇 |
2019年 | 556篇 |
2018年 | 516篇 |
2017年 | 393篇 |
2016年 | 532篇 |
2015年 | 675篇 |
2014年 | 864篇 |
2013年 | 834篇 |
2012年 | 992篇 |
2011年 | 852篇 |
2010年 | 470篇 |
2009年 | 471篇 |
2008年 | 494篇 |
2007年 | 435篇 |
2006年 | 322篇 |
2005年 | 276篇 |
2004年 | 245篇 |
2003年 | 157篇 |
2002年 | 175篇 |
2001年 | 80篇 |
2000年 | 86篇 |
1999年 | 65篇 |
1998年 | 51篇 |
1997年 | 47篇 |
1996年 | 34篇 |
1995年 | 41篇 |
1994年 | 37篇 |
1993年 | 23篇 |
1992年 | 29篇 |
1991年 | 31篇 |
1990年 | 31篇 |
1989年 | 33篇 |
1988年 | 14篇 |
1987年 | 19篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1977年 | 5篇 |
1973年 | 3篇 |
1966年 | 2篇 |
1962年 | 2篇 |
1950年 | 2篇 |
1940年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 614 毫秒
131.
132.
The relationship between rs3746444 T>C single-nucleotide polymorphism (SNP) in microRNA (mir)-499 and risk of gastric cancer (GC) has been widely investigated. However, the association was still unconfirmed. Here, we first recruited 490 GC patients and 1476 controls, and conducted a case-control study. And we did not find any association between rs3746444 T>C SNP polymorphism and risk of GC. Subsequently, we conducted a meta-analysis to explore the association of mir-499 rs3746444 polymorphism with GC development. Two authors searched the PubMed and EMBASE databases up to October 15, 2019 independently. Finally, nine literatures involving 12 independent studies were included. In total, 3954 GC cases and 9745 controls were recruited for meta-analysis. The results suggested that allele model, homozygote model and recessive model could increase the risk of overall GC (P = 0.002, 0.009 and 0.013, respectively). When we excluded the studies violated HWE, this association was also found in allele model (P = 0.020) and dominant model (P= 0.044). In subgroup analyses, we identified that rs3746444 SNP in mir-499 increased the risk of GC in Asians and gastric cardiac adenocarcinoma (GCA) subgroups. No significant bias of selection was found (all P>0.1). Test of sensitivity analysis indicated that our findings were stable. Additionally, we found that the power value was 0.891 in the allele model, suggesting the reliability of our findings. In summary, our analysis confirmed the association between rs3746444 and the risk of GC, especially in Asians and in patients with GCA. 相似文献
133.
Yuhua Chen Hao Zhou Zhendong Wang Zhanghao Huang Jinjie Wang Miaosen Zheng Xuejun Ni Lei Liu 《Bioscience reports》2021,41(5)
Background: Esophageal cancer (ESCA) is one of the most commonly diagnosed cancers in the world. Tumor immune microenvironment is closely related to tumor prognosis. The present study aimed at analyzing the competing endogenous RNA (ceRNA) network and tumor-infiltrating immune cells in ESCA.Methods: The expression profiles of mRNAs, lncRNAs, and miRNAs were downloaded from the Cancer Genome Atlas database. A ceRNA network was established based on the differentially expressed RNAs by Cytoscape. CIBERSORT was applied to estimate the proportion of immune cells in ESCA. Prognosis-associated genes and immune cells were applied to establish prognostic models basing on Lasso and multivariate Cox analyses. The survival curves were constructed with Kaplan–Meier method. The predictive efficacy of the prognostic models was evaluated by the receiver operating characteristic (ROC) curves.Results: The differentially expressed mRNAs, lncRNAs, and miRNAs were identified. We constructed the ceRNA network including 23 lncRNAs, 19 miRNAs, and 147 mRNAs. Five key molecules (HMGB3, HOXC8, HSPA1B, KLHL15, and RUNX3) were identified from the ceRNA network and five significant immune cells (plasma cells, T cells follicular helper, monocytes, dendritic cells activated, and neutrophils) were selected via CIBERSORT. The ROC curves based on key genes and significant immune cells all showed good sensitivity (AUC of 3-year survival: 0.739, AUC of 5-year survival: 0.899, AUC of 3-year survival: 0.824, AUC of 5-year survival: 0.876). There was certain correlation between five immune cells and five key molecules.Conclusion: The present study provides an effective bioinformatics basis for exploring the potential biomarkers of ESCA and predicting its prognosis. 相似文献
134.
135.
Molecular and Cellular Biochemistry - Spermatogenesis is usually accompanied throughout mammalian lifetime, transmitting genetic information to the next generation, which is mainly dependent on the... 相似文献
136.
Hao Yu-Qin Liu Ke-Wei Zhang Xin Kang Shu-Xia Zhang Kun Han Wurihan Li Li Li Zhe-Hai 《Molecular and cellular biochemistry》2021,476(3):1455-1465
Molecular and Cellular Biochemistry - Melanoma ranks second in aggressive tumors, and the occurrence of metastasis in melanoma results in a persistent drop in the survival rate of patients.... 相似文献
137.
Jin Hao Kim Hak Sung Yu Seung Taek Shin Sae Ron Lee Sung Hee Seo Geom Seog 《Molecular biology reports》2021,48(2):1171-1180
Molecular Biology Reports - A large body of research has demonstrated a synergistic anticancer effect between docosahexaenoic acid (DHA) and standard chemotherapy regimens against colorectal cancer... 相似文献
138.
Shou-Yin Li Cong Chen Zhi-Yi Jia Qing Li Zhi-Zhen Tang Man-Fang Zhong Han Zhu De-Jun Hao 《Journal of Applied Entomology》2021,145(6):530-542
The weevil Pagiophloeus tsushimanus Morimoto (Coleoptera: Curculionidae), native to Eastern Asia, is a wood-boring pest that causes severe damage to camphor trees (Cinnamomum sp.) in Shanghai, China. Other Lauraceae tree species that grew sympatrically with this pest in close proximity could face a potential threat. To assess the potential risks of host shift, we explored the phenotypic associations between preference and performance in P. tsushimanus reared on three Lauraceae tree species. In a no-choice experiment offering branches of each plant as diet material and oviposition sites, we found that individuals reared on Cinnamomum camphora (L.) Presl (Laurales: Lauraceae) exhibited the strongest performance with shorter development time, higher survival and growth rate in the immature stage, longer longevity and greater fecundity in adults. In contrast, those on novel Lauraceae tree species (Cinnamomum chekiangensis Nakai and Phoebe chekiangensis Shang) had difficulty completing their whole life cycle due to significantly lower survival and reproduction. In a multiple-choice experiment, C. camphora was established as the preferred host. However, we found that the larval experiences on the non-preferred host plants contributed to an increased preference for that plant species. These results indicated that both the preference-performance hypothesis and the Hopkins’ host selection principle are applicable in this weevil under experimental conditions. It is possible that although the weevil performed poorly on two novel Lauraceae tree species, under favourable conditions their surviving offspring could evolve into a new host-specific population. Consequently, this weevil pest needs to be monitored on these novel Lauraceae tree species. 相似文献
139.
TzuCheng Sung YiPeng Jiang JheYu Hsu QingDong Ling Hao Chen Suresh S. Kumar Yung Chang ShihTien Hsu Qingsong Ye Akon Higuchi 《Cell proliferation》2021,54(3)
IntroductionIt is important to prepare ‘hypoimmunogenic’ or ‘universal’ human pluripotent stem cells (hPSCs) with gene‐editing technology by knocking out or in immune‐related genes, because only a few hypoimmunogenic or universal hPSC lines would be sufficient to store for their off‐the‐shelf use. However, these hypoimmunogenic or universal hPSCs prepared previously were all genetically edited, which makes laborious processes to check and evaluate no abnormal gene editing of hPSCs.MethodsUniversal human‐induced pluripotent stem cells (hiPSCs) were generated without gene editing, which were reprogrammed from foetal stem cells (human amniotic fluid stem cells) with mixing 2‐5 allogenic donors but not with single donor. We evaluated human leucocyte antigen (HLA)‐expressing class Ia and class II of our hiPSCs and their differentiated cells into embryoid bodies, cardiomyocytes and mesenchymal stem cells. We further evaluated immunogenic response of transient universal hiPSCs with allogenic mononuclear cells from survival rate and cytokine production, which were generated by the cells due to immunogenic reactions.ResultsOur universal hiPSCs during passages 10‐25 did not have immunogenic reaction from allogenic mononuclear cells even after differentiation into cardiomyocytes, embryoid bodies and mesenchymal stem cells. Furthermore, the cells including the differentiated cells did not express HLA class Ia and class II. Cardiomyocytes differentiated from transient universal hiPSCs at passage 21‐22 survived and continued beating even after treatment with allogenic mononuclear cells. 相似文献
140.
Chen Zhang Qisheng Zuo Man Wang Hao Chen Nana He Jing Jin Tingting Li Jingyi Jiang Xia Yuan Jiancheng Li Xiang Shi Ming Zhang Hao Bai Yang Zhang Qi Xu Hengmi Cui Guobin Chang Jiuzhou Song Hongyan Sun Yani Zhang Guohong Chen Bichun Li 《Journal of cellular physiology》2021,236(2):1391-1400
The development of primordial germ cells (PGCs) undergoes epigenetic modifications. The study of histone methylation in regulating PGCs is beneficial to understand the development and differentiation mechanism of germ stem cells. Notably, it provides a theoretical basis for directed induction and mass acquisition in vitro. However, little is known about the regulation of PGC formation by histone methylation. Here, we found the high enrichment of H3K4me2 in the blastoderm, genital ridges, and testis. Chromatin immunoprecipitation sequencing was performed and the results revealed that genomic H3K4me2 is dynamic in embryonic stem cells, PGCs, and spermatogonial stem cells. This trend was consistent with the H3K4me2 enrichment in the gene promoter region. Additionally, narrow region triggered PGC‐related genes (Bmp4, Wnt5a, and Tcf7l2) and signaling pathways (Wnt and transforming growth factor‐β). After knocking down histone methylase Mll2 in vitro and vivo, the level of H3K4me2 decreased, inhibiting Cvh and Blimp1 expression, then repressing the formation of PGCs. Taken together, our study revealed the whole genome map of H3K4me2 in the formation of PGCs, contributing to improve the epigenetic study in PGC formation and providing materials for bird gene editing and rescue of endangered birds. 相似文献