全文获取类型
收费全文 | 7933篇 |
免费 | 707篇 |
国内免费 | 573篇 |
专业分类
9213篇 |
出版年
2024年 | 20篇 |
2023年 | 114篇 |
2022年 | 278篇 |
2021年 | 447篇 |
2020年 | 299篇 |
2019年 | 349篇 |
2018年 | 325篇 |
2017年 | 234篇 |
2016年 | 384篇 |
2015年 | 508篇 |
2014年 | 653篇 |
2013年 | 596篇 |
2012年 | 714篇 |
2011年 | 607篇 |
2010年 | 423篇 |
2009年 | 335篇 |
2008年 | 413篇 |
2007年 | 401篇 |
2006年 | 291篇 |
2005年 | 250篇 |
2004年 | 198篇 |
2003年 | 187篇 |
2002年 | 134篇 |
2001年 | 139篇 |
2000年 | 129篇 |
1999年 | 146篇 |
1998年 | 89篇 |
1997年 | 77篇 |
1996年 | 68篇 |
1995年 | 48篇 |
1994年 | 58篇 |
1993年 | 31篇 |
1992年 | 49篇 |
1991年 | 39篇 |
1990年 | 24篇 |
1989年 | 31篇 |
1988年 | 22篇 |
1987年 | 29篇 |
1986年 | 13篇 |
1985年 | 20篇 |
1984年 | 12篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有9213条查询结果,搜索用时 15 毫秒
991.
992.
Purpose: Cervical cancer (CC) is one of the most general gynecological malignancies and is associated with high morbidity and mortality. We aimed to select candidate genes related to the diagnosis and prognosis of CC.Methods: The mRNA expression profile datasets were downloaded. We also downloaded RNA-sequencing gene expression data and related clinical materials from TCGA, which included 307 CC samples and 3 normal samples. Differentially expressed genes (DEGs) were obtained by R software. GO function analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs were performed in the DAVID dataset. Using machine learning, the optimal diagnostic mRNA biomarkers for CC were identified. We used qRT-PCR and Human Protein Atlas (HPA) database to exhibit the differences in gene and protein levels of candidate genes.Results: A total of 313 DEGs were screened from the microarray expression profile datasets. DNA methyltransferase 1 (DNMT1), Chromatin Assembly Factor 1, subunit B (CHAF1B), Chromatin Assembly Factor 1, subunit A (CHAF1A), MCM2, CDKN2A were identified as optimal diagnostic mRNA biomarkers for CC. Additionally, the GEPIA database showed that the DNMT1, CHAF1B, CHAF1A, MCM2 and CDKN2A were associated with the poor survival of CC patients. HPA database and qRT-PCR confirmed that these genes were highly expressed in CC tissues.Conclusion: The present study identified five DEmRNAs, including DNMT1, CHAF1B, CHAF1A, MCM2 and Kinetochore-related protein 1 (KNTC1), as potential diagnostic and prognostic biomarkers of CC. 相似文献
993.
热带胶茶人工群落中土壤动物季节变化的研究 总被引:17,自引:1,他引:17
热带胶茶人工群落中土壤动物季节变化的研究邓晓保(中国科学院昆明生态研究所,650223)SeasonalVariationofSoilAnimalsinMan-MadeRubber-TeaCommunityinTropics.¥DengXi-aoba... 相似文献
994.
一、西藏自然条件概述西藏高原位于北纬27°00′—36°05′,东经78°05′—99°00′内,面积约120万平方公里。境内有东西向和南北向两组大山脉,形成西北高,东南低的地势。在东西向山脉中,由南往北依次有著名的喜马拉雅山、冈底斯山、念青唐古拉山、唐古拉山、喀喇昆仑山和昆仑山。南北向山脉分布在藏东,由伯舒拉岭、他念他翁山等,组成我国著名的横断山区的西半部。境内大部分地区海拔高度在4000米以上,与周围地区相比,相对高差达2000—3000米。这一又高又大的高原,在气候上具有自己的特点;高原内不同地域又有明显分异。(见表一) 相似文献
995.
Wen-Jie Fan He-Ping Li He-Shui Zhu Shi-Ping Sui Pei-Ge Chen Yue Deng Tong-Ming Sui Yue-Ying Wang 《Biotechnology letters》2016,38(11):1839-1849
Objectives
To determine the effect of NF-κB on cell proliferation and apoptosis, we investigate the expression of inflammation and apoptosis-related factors in the bovine mammary epithelial cell line, MAC-T.Results
MAC-T cells were cultured in vitro and MTT and LDH assays used to determine the effects of lipopolysaccharide (LPS) on proliferation and cytotoxicity respectively. RT-PCR and western blotting were used to evaluate the effect of LPS and NF-κB inhibition [pyrrolidine dithiocarbamate (PDTC) treatment] on the expression of inflammation and apoptosis-related factors. LPS significantly inhibited MAC-T cell proliferation in a dose- and time-dependent manner. Furthermore, LPS promoted apoptosis while the NF-кB inhibitor PDTC attenuated this effect. After LPS treatment, the NF-кB signaling pathway was activated, and the expression of inflammation and apoptosis-related factors increased. When PDTC blocked NF-кB signaling, the expression of inflammation and apoptosis-related factors were decreased in MAC-T cells.Conclusions
LPS activates the TLR4/NF-κB signaling pathway, inhibits proliferation and promotes apoptosis in MAC-T cells. NF-кB inhibition attenuates MAC-T cell apoptosis and TLR4/NF-κB signaling pathway. NF-кB inhibitor alleviating MAC-T cell apoptosis is presumably modulated by NF-кB.996.
Astra Dinculescu Rachel M. Stupay Wen-Tao Deng Frank M. Dyka Seok-Hong Min Sanford L. Boye Vince A. Chiodo Carolina E. Abrahan Ping Zhu Qiuhong Li Enrica Strettoi Elena Novelli Kerstin Nagel-Wolfrum Uwe Wolfrum W. Clay Smith William W. Hauswirth 《PloS one》2016,11(2)
Usher syndrome type III (USH3A) is an autosomal recessive disorder caused by mutations in clarin-1 (CLRN1) gene, leading to progressive retinal degeneration and sensorineural deafness. Efforts to develop therapies for preventing photoreceptor cell loss are hampered by the lack of a retinal phenotype in the existing USH3 mouse models and by conflicting reports regarding the endogenous retinal localization of clarin-1, a transmembrane protein of unknown function. In this study, we used an AAV-based approach to express CLRN1 in the mouse retina in order to determine the pattern of its subcellular localization in different cell types. We found that all major classes of retinal cells express AAV-delivered CLRN1 driven by the ubiquitous, constitutive small chicken β-actin promoter, which has important implications for the design of future USH3 gene therapy studies. Within photoreceptor cells, AAV-expressed CLRN1 is mainly localized at the inner segment region and outer plexiform layer, similar to the endogenous expression of other usher proteins. Subretinal delivery using a full strength viral titer led to significant loss of retinal function as evidenced by ERG analysis, suggesting that there is a critical limit for CLRN1 expression in photoreceptor cells. Taken together, these results suggest that CLRN1 expression is potentially supported by a variety of retinal cells, and the right combination of AAV vector dose, promoter, and delivery method needs to be selected to develop safe therapies for USH3 disorder. 相似文献
997.
Rong Hai Lei Zhang YuFang Pei LanJuan Zhao Shu Ran YingYing Han XueZhen Zhu Hui Shen Qing Tian HongWen Deng 《中国科学:生命科学英文版》2012,55(6):516-520
Lean body mass (LBM) and age at menarche (AAM) are two important complex traits for human health. The aim of this study was to identify pleiotropic genes for both traits using a powerful bivariate genome-wide association study (GWAS). Two studies, a discovery study and a replication study, were performed. In the discovery study, 909622 single nucleotide polymorphisms (SNPs) were genotyped in 801 unrelated female Han Chinese subjects using the Affymetrix human genome-wide SNP array 6.0 platform. Then, a bivariate GWAS was performed to identify the SNPs that may be important for LBM and AAM. In the replication study, significant findings from the discovery study were validated in 1692 unrelated Caucasian female subjects. One SNP rs3027009 that was bivariately associated with left arm lean mass and AAM in the discovery samples (P=7.26×10?6) and in the replication samples (P=0.005) was identified. The SNP is located at the upstream of DARC (Duffy antigen receptor for chemokines) gene, suggesting that DARC may play an important role in regulating the metabolisms of both LBM and AAM. 相似文献
998.
Over the past decade there has been a growing acknowledgement that a large proportion of proteins within most proteomes contain disordered regions. Disordered regions are segments of the protein chain which do not adopt a stable structure. Recognition of disordered regions in a protein is of great importance for protein structure prediction, protein structure determination and function annotation as these regions have a close relationship with protein expression and functionality. As a result, a great many protein disorder prediction methods have been developed so far. Here, we present an overview of current protein disorder prediction methods including an analysis of their advantages and shortcomings. In order to help users to select alternative tools under different circumstances, we also evaluate 23 disorder predictors on the benchmark data of the most recent round of the Critical Assessment of protein Structure Prediction (CASP) and assess their accuracy using several complementary measures. 相似文献
999.
1000.
Jiayan Shen Long Li Kehan Xu Kaijun Wang Yiping Du Ting Wu Huipeng Deng 《Luminescence》2023,38(11):1938-1945
A rapid and sensitive strategy was proposed for the detection of fluoranthene (FL), which is a polycyclic aromatic hydrocarbon (PAH), in water samples. In this work, syringe solid-phase extraction (SPE) combined with solid-phase fluorescence spectrometry was used to determine FL in PAHs polluted environmental samples. The fluorescence signals were directly monitored on the membrane surface after FL was enriched by syringe SPE. Under the optimal conditions, the proposed method showed a linear relationship in the concentration range 2–50 μg/L with a correlation coefficient (R2) of 0.998, and the limit of detection was 0.143 μg/L. The recoveries varied from 93.47% to 109.81% in the actual samples, with the relative standard deviations (n = 3) ranging from 2.06% to 6.32%. According to the results, the established method can be applied in the field of rapid detection as it is fast, simple, portable, and highly sensitive, and has strong anti-interference. 相似文献