全文获取类型
收费全文 | 6905篇 |
免费 | 77篇 |
国内免费 | 42篇 |
出版年
2023年 | 76篇 |
2022年 | 91篇 |
2021年 | 40篇 |
2020年 | 22篇 |
2019年 | 32篇 |
2018年 | 28篇 |
2017年 | 27篇 |
2016年 | 21篇 |
2015年 | 30篇 |
2014年 | 214篇 |
2013年 | 171篇 |
2012年 | 149篇 |
2011年 | 169篇 |
2010年 | 129篇 |
2009年 | 138篇 |
2008年 | 150篇 |
2007年 | 167篇 |
2006年 | 149篇 |
2005年 | 317篇 |
2004年 | 478篇 |
2003年 | 381篇 |
2002年 | 248篇 |
2001年 | 256篇 |
2000年 | 202篇 |
1999年 | 253篇 |
1998年 | 200篇 |
1997年 | 152篇 |
1996年 | 242篇 |
1995年 | 283篇 |
1994年 | 263篇 |
1993年 | 238篇 |
1992年 | 230篇 |
1991年 | 194篇 |
1990年 | 159篇 |
1989年 | 145篇 |
1988年 | 152篇 |
1987年 | 123篇 |
1986年 | 116篇 |
1985年 | 77篇 |
1984年 | 91篇 |
1983年 | 20篇 |
1982年 | 65篇 |
1981年 | 64篇 |
1980年 | 61篇 |
1979年 | 42篇 |
1978年 | 40篇 |
1977年 | 41篇 |
1976年 | 40篇 |
1974年 | 12篇 |
1972年 | 16篇 |
排序方式: 共有7024条查询结果,搜索用时 31 毫秒
1.
《Molecular & cellular proteomics : MCP》2023,22(1):100480
Alternative ORFs (AltORFs) are unannotated sequences in genome that encode novel peptides or proteins named alternative proteins (AltProts). Although ribosome profiling and bioinformatics predict a large number of AltProts, mass spectrometry as the only direct way of identification is hampered by the short lengths and relative low abundance of AltProts. There is an urgent need for improvement of mass spectrometry methodologies for AltProt identification. Here, we report an approach based on size-exclusion chromatography for simultaneous enrichment and fractionation of AltProts from complex proteome. This method greatly simplifies the variance of AltProts discovery by enriching small proteins smaller than 40 kDa. In a systematic comparison between 10 methods, the approach we reported enabled the discovery of more AltProts with overall higher intensities, with less cost of time and effort compared to other workflows. We applied this approach to identify 89 novel AltProts from mouse liver, 39 of which were differentially expressed between embryonic and adult mice. During embryonic development, the upregulated AltProts were mainly involved in biological pathways on RNA splicing and processing, whereas the AltProts involved in metabolisms were more active in adult livers. Our study not only provides an effective approach for identifying AltProts but also novel AltProts that are potentially important in developmental biology. 相似文献
2.
Volatile chemicals in the environment provide ethologically important information to many animals. However, how animals learn to use this information is only beginning to be understood. This review highlights recent experimental advances elucidating olfactory learning in rodents, ranging from adaptations to the environment to task-dependent refinement and multisensory associations. The broad range of phenomena, mechanisms, and brain areas involved demonstrate the complex and multifaceted nature of olfactory learning. 相似文献
3.
《Chemical Speciation and Bioavailability》2013,25(1-4):75-77
AbstractIn this paper, we describe a series of laboratory experiments which quantify the rate of Cr6+ reduction by Fe0. The main goal of these experiments was to determine the removal efficiency of Cr6+ by iron. The results indicate that Fe0 reduces Cr6+ to Cr3+ under alkaline and slightly acidic conditions. The removal efficiency rises with an increase of the initial concentration of Cr6+ (1 mg/L to 10 mg/L) when the quantity of Fe0 is stable. The removal efficiency increases as the quantity of Fe0 is raised when other conditions are constant. The removal efficiency would not be affected by other inorganic ions unless they were present at very high concentrations. When the initial concentration Cr6+ is 10mg/L and pH is 6.5–7.7, the final concentration of Cr6+ in effluent is less than 0.05 mg/L and the total Fe is less than 0.3 mg/L in effluent. 相似文献
4.
Age-related changes in amounts of myelin proteins from rat sciatic nerve or spinal root were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). In the aged peripheral nerve myelin, the relative amounts of band 105K and proteins X and Y increased, whereas those of proteins P0 and P1 and band 190K decreased. Band 105K purified by preparative SDS-PAGE exhibited three bands of 105K, 28K, and 21K at the second electrophoresis. A repeated SDS-PAGE did not improve the purity of bank 105K, but increased the ratio of 21K to 28K. Compared with P0 protein, band 105K has a very similar peptide map pattern and amino acid composition, as well as the identical NH2 terminal residue, isoleucine. These findings suggest that band 105K is an aggregate form of P0 protein and its fragment, 21K. The 21K protein is a distinct entity from X protein. The quantitative and qualitative alterations in myelin proteins, as we report here, may reflect continuing demyelination and remyelination in aged peripheral nerves. 相似文献
5.
6.
7.
Marta Menga Rosa Trotta Rosella Scrima Consiglia Pacelli Veronica Silvestri Claudia Piccoli Nazzareno Capitanio Arcangelo Liso 《生物化学与生物物理学报:疾病的分子基础》2018,1864(3):685-699
Fever-like hyperthermia is known to stimulate innate and adaptive immune responses. Hyperthermia-induced immune stimulation is also accompanied with, and likely conditioned by, changes in the cell metabolism and, in particular, mitochondrial metabolism is now recognized to play a pivotal role in this context, both as energy supplier and as signaling platform. In this study we asked if challenging human monocyte-derived dendritic cells with a relatively short-time thermal shock in the fever-range, typically observed in humans, caused alterations in the mitochondrial oxidative metabolism. We found that following hyperthermic stress (3 h exposure at 39 °C) TNF-α-releasing dendritic cells undergo rewiring of the oxidative metabolism hallmarked by decrease of the mitochondrial respiratory activity and of the oxidative phosphorylation and increase of lactate production. Moreover, enhanced production of reactive oxygen and nitrogen species and accumulation of mitochondrial Ca2+ was consistently observed in hyperthermia-conditioned dendritic cells and exhibited a reciprocal interplay. The hyperthermia-induced impairment of the mitochondrial respiratory activity was (i) irreversible following re-conditioning of cells to normothermia, (ii) mimicked by exposing normothermic cells to the conditioned medium of the hyperthermia-challenged cells, (iii) largely prevented by antioxidant and inhibitors of the nitric oxide synthase and of the mitochondrial calcium porter, which also inhibited release of TNF-α. These observations combined with gene expression analysis support a model based on a thermally induced autocrine signaling, which rewires and sets a metabolism checkpoint linked to immune activation of dendritic cells. 相似文献
8.
The spectra of k-mer frequencies can reveal the structures and evolution of genome sequences. We confirmed that the trimodal spectrum of 8-mers in human genome sequences is distinguished only by CG2, CG1 and CG0 8-mer sets, containing 2,1 or 0 CpG, respectively. This phenomenon is called independent selection law. The three types of CG 8-mers were considered as different functional elements. We conjectured that (1) nucleosome binding motifs are mainly characterized by CG1 8-mers and (2) the core structural units of CpG island sequences are predominantly characterized by CG2 8-mers. To validate our conjectures, nucleosome occupied sequences and CGI sequences were extracted, then the sequence parameters were constructed through the information of the three CG 8-mer sets respectively. ROC analysis showed that CG1 8-mers are more preference in nucleosome occupied segments (AUC > 0.7) and CG2 8-mers are more preference in CGI sequences (AUC > 0.99). This validates our conjecture in principle. 相似文献
9.
《Molecular & cellular proteomics : MCP》2023,22(2):100479
Neuropeptides regulate animal physiology and behavior, making them widely studied targets of functional genetics research. While the field often relies on differential -omics approaches to build hypotheses, no such method exists for neuropeptidomics. It would nonetheless be valuable for studying behaviors suspected to be regulated by neuropeptides, especially when little information is otherwise available. This includes nictation, a phoretic strategy of Caenorhabditis elegans dauers that parallels host-finding strategies of infective juveniles of many pathogenic nematodes. We here developed a targeted peptidomics method for the model organism C. elegans and show that 161 quantified neuropeptides are more abundant in its dauer stage compared with L3 juveniles. Many of these have orthologs in the commercially relevant pathogenic nematode Steinernema carpocapsae, in whose infective juveniles, we identified 126 neuropeptides in total. Through further behavioral genetics experiments, we identify flp-7 and flp-11 as novel regulators of nictation. Our work advances knowledge on the genetics of nictation behavior and adds comparative neuropeptidomics as a tool to functional genetics workflows. 相似文献
10.
The Circadian Clock Gene Circuit Controls Protein and Phosphoprotein Rhythms in Arabidopsis thaliana