全文获取类型
收费全文 | 137819篇 |
免费 | 3607篇 |
国内免费 | 901篇 |
专业分类
142327篇 |
出版年
2024年 | 52篇 |
2023年 | 175篇 |
2022年 | 566篇 |
2021年 | 912篇 |
2020年 | 568篇 |
2019年 | 683篇 |
2018年 | 12547篇 |
2017年 | 11259篇 |
2016年 | 8706篇 |
2015年 | 2881篇 |
2014年 | 2929篇 |
2013年 | 3253篇 |
2012年 | 7999篇 |
2011年 | 16202篇 |
2010年 | 14057篇 |
2009年 | 10137篇 |
2008年 | 12558篇 |
2007年 | 13978篇 |
2006年 | 2783篇 |
2005年 | 2845篇 |
2004年 | 3099篇 |
2003年 | 2866篇 |
2002年 | 2375篇 |
2001年 | 1552篇 |
2000年 | 1384篇 |
1999年 | 1012篇 |
1998年 | 400篇 |
1997年 | 359篇 |
1996年 | 254篇 |
1995年 | 209篇 |
1994年 | 212篇 |
1993年 | 201篇 |
1992年 | 346篇 |
1991年 | 332篇 |
1990年 | 273篇 |
1989年 | 233篇 |
1988年 | 190篇 |
1987年 | 177篇 |
1986年 | 131篇 |
1985年 | 105篇 |
1984年 | 85篇 |
1983年 | 101篇 |
1982年 | 65篇 |
1981年 | 53篇 |
1980年 | 55篇 |
1979年 | 69篇 |
1978年 | 51篇 |
1974年 | 63篇 |
1972年 | 278篇 |
1971年 | 308篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
Frances M Dupont 《BMC plant biology》2008,8(1):39
Background
By definition, amyloplasts are plastids specialized for starch production. However, a proteomic study of amyloplasts isolated from wheat (Triticum aestivum Butte 86) endosperm at 10 days after anthesis (DPA) detected enzymes from many other metabolic and biosynthetic pathways. To better understand the role of amyloplasts in food production, the data from that study were evaluated in detail and an amyloplast metabolic map was outlined. 相似文献943.
Davoud Nouri Inanlou Bagher Yakhchali Hossein Khanahmad Mossa Gardaneh Hesam Movassagh Reza Ahangari Cohan Mehdi Shafiee Ardestani Reza Mahdian Sirous Zeinali 《Biotechnology letters》2010,32(11):1615-1621
We have developed an integrase-defective lentiviral (LV) vector in combination with a gene-targeting approach for gene therapy
of β-thalassemia. The β-globin gene-targeting construct has two homologous stems including sequence upstream and downstream
of the β-globin gene, a β-globin gene positioned between hygromycin and neomycin resistant genes and a herpes simplex virus
type 1 thymidine kinase (HSVtk) suicide gene. Utilization of integrase-defective LV as a vector for the β-globin gene increased the number of selected clones
relative to non-viral methods. This method represents an important step toward the ultimate goal of a clinical gene therapy
for β-thalassemia. 相似文献
944.
Screening of promoters from metagenomic DNA and their use for the construction of expression vectors
Han SS Lee JY Kim WH Shin HJ Kim GJ 《Journal of microbiology and biotechnology》2008,18(10):1634-1640
This study was focused on the screening of valuable genetic resources, such as promoters from metagenome, and describes a promoter trapping system with a bidirectional probe concept, which can select promoters or operons from various biological resources including metagenomic DNA. A pair of reporters, GFP and DsRed, facing the opposite direction without promoters, is an effective system that can function regardless of the direction of inserted promoters. The feasibility of this system was tested for the isolation of constitutively expressed promoters in E. coli from a soil metagenome, resulting in a potential pool of various promoters for practical application. The analyses of structural organization of the trapped genes demonstrated that constitutively expressible promoters in E. coli were broadly distributed within the metagenome, and suggested that some promoters were useful for the construction of expression vectors. Based on these observations, three constitutive promoters were employed in the expression vector system and their potentials for practical application were evaluated in terms of expression level, protein solubility, and effects on host growth. 相似文献
945.
Jang Hye Jin Choi Ji Yeon Kim Kangjoon Yong Seung Hyun Kim Yeon Wook Kim Song Yee Kim Eun Young Jung Ji Ye Kang Young Ae Park Moo Suk Kim Young Sam Cho Young-Jae Lee Sang Hoon 《Respiratory research》2021,22(1):1-9
IL-35 subunit EBI3 is up-regulated in pulmonary fibrosis tissues. In this study, we investigated the pathological role of EBI3 in pulmonary fibrosis and dissected the underlying molecular mechanism. Bleomycin-induced pulmonary fibrosis mouse model was established, and samples were performed gene expression analyses through RNAseq, qRT-PCR and Western blot. Wild type and EBI3 knockout mice were exposed to bleomycin to investigate the pathological role of IL-35, via lung function and gene expression analyses. Primary lung epithelial cells were used to dissect the regulatory mechanism of EBI3 on STAT1/STAT4 and STAT3. IL-35 was elevated in both human and mouse with pulmonary fibrosis. EBI3 knockdown aggravated the symptoms of pulmonary fibrosis in mice. EBI3 deficiency enhanced the expressions of fibrotic and extracellular matrix-associated genes. Mechanistically, IL-35 activated STAT1 and STAT4, which in turn suppressed DNA enrichment of STAT3 and inhibited the fibrosis process. IL-35 might be one of the potential therapeutic targets for bleomycin-induced pulmonary fibrosis. 相似文献
946.
947.
Gene delivery by lentivirus vectors 总被引:13,自引:0,他引:13
The capacity to efficiently transduce nondividing cells, shuttle large genetic payloads, and maintain stable long-term transgene
expression are attributes that have brought lentiviral vectors to the forefront of gene delivery vehicles for research and
therapeutic applications in a clinical setting. Our discussion initiates with advances in lentiviral vector development and
how these sophisticated lentiviral vectors reflect improvements in safety, regarding the prevention of replication competent
lentiviruses (RCLs), vector mobilization, and insertional mutagenesis. Additionally, we describe conventional molecular regulatory
systems to manage gene expression levels in a spatial and temporal fashion in the context of a lentiviral vector. State of
the art technology for lentiviral vector production by transient transfection and packaging cell lines are explicitly presented
with current practices used for concentration, purification, titering, and determining the safety of a vector stock. We summarize
lentiviral vector applications that have received a great deal of attention in recent years including the generation of transgenic
animals and the stable delivery of RNA interference molecules. Concluding remarks address some of the successes in preclinical
animals, and the recent transition of lentiviral vectors to human clinical trials as therapy for a variety of infectious and
genetic diseases. 相似文献
948.
Cooperation within Actin Filament in Vertebrate Skeletal Muscle 总被引:56,自引:0,他引:56
When actin molecules form “rigor complexes” with nucleotide-free myosin, tropomn binds calcium with greater affinity and in a cooperative response the remaining actin molecules not cornplexed with myosin are “turned on” even though calcium is absent. 相似文献
949.
950.
Genomewide association studies (GWAS) have proven a powerful hypothesis-free method to identify common disease-associated
variants. Even quite large GWAS, however, have only at best identified moderate proportions of the genetic variants contributing
to disease heritability. To provide cost-effective genotyping of common and rare variants to map the remaining heritability
and to fine-map established loci, the Immunochip Consortium has developed a 200,000 SNP chip that has been produced in very
large numbers for a fraction of the cost of GWAS chips. This chip provides a powerful tool for immunogenetics gene mapping. 相似文献