全文获取类型
收费全文 | 5069篇 |
免费 | 368篇 |
国内免费 | 3篇 |
专业分类
5440篇 |
出版年
2024年 | 6篇 |
2023年 | 25篇 |
2022年 | 68篇 |
2021年 | 92篇 |
2020年 | 75篇 |
2019年 | 97篇 |
2018年 | 144篇 |
2017年 | 107篇 |
2016年 | 176篇 |
2015年 | 257篇 |
2014年 | 330篇 |
2013年 | 359篇 |
2012年 | 463篇 |
2011年 | 449篇 |
2010年 | 274篇 |
2009年 | 249篇 |
2008年 | 317篇 |
2007年 | 315篇 |
2006年 | 248篇 |
2005年 | 233篇 |
2004年 | 251篇 |
2003年 | 193篇 |
2002年 | 164篇 |
2001年 | 102篇 |
2000年 | 104篇 |
1999年 | 68篇 |
1998年 | 26篇 |
1997年 | 26篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 19篇 |
1991年 | 24篇 |
1990年 | 18篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1982年 | 5篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有5440条查询结果,搜索用时 15 毫秒
71.
Joonam Park Kyu Tae Kim Dae Yang Oh Dahee Jin Dohwan Kim Yoon Seok Jung Yong Min Lee 《Liver Transplantation》2020,10(35)
The digital twin technique has been broadly utilized to efficiently and effectively predict the performance and problems associated with real objects via a virtual replica. However, the digitalization of twin electrochemical systems has not been achieved thus far, owing to the large amount of required calculations of numerous and complex differential equations in multiple dimensions. Nevertheless, with the help of continuous progress in hardware and software technologies, the fabrication of a digital twin‐driven electrochemical system and its effective utilization have become a possibility. Herein, a digital twin‐driven all‐solid‐state battery with a solid sulfide electrolyte is built based on a voxel‐based microstructure. Its validity is verified using experimental data, such as effective electronic/ionic conductivities and electrochemical performance, for LiNi0.70Co0.15Mn0.15O2 composite electrodes employing Li6PS5Cl. The fundamental performance of the all‐solid‐state battery is scrutinized by analyzing simulated physical and electrochemical behaviors in terms of mass transport and interfacial electrochemical reaction kinetics. The digital twin model herein reveals valuable but experimentally inaccessible time‐ and space‐resolved information including dead particles, specific contact area, and charge distribution in the 3D domain. Thus, this new computational model is bound to rapidly improve the all‐solid‐state battery technology by saving the research resources and providing valuable insights. 相似文献
72.
73.
Jung Hwan Kim Kyung Won Shim Yeong Sook Yoon Sang Yeoup Lee Sung Soo Kim Sang Woo Oh 《PloS one》2012,7(9)
Background
Cigarette smoking and obesity are leading public health concerns. Both increase the risk for cardiovascular disease, cancer, and metabolic abnormalities. This study was conducted to assess the association between cigarette smoking and different types of obesity.Methodology/Principal Findings
Two hundred eighty-three visitors to university hospitals located in four main provinces of South Korea were participated. All participants were classified as either current/past or never smokers and were divided into quartiles according to the total pack-years. Body mass index, waist circumference, total body fat percentage, and area of visceral and abdominal subcutaneous fat were measured. These results of each groups were compared. Waist circumference, and visceral fat area showed a J- or U-shaped association with total smoking amount during a lifetime. After restricting the analyses to past/current smokers, we found significant dose-dependent associations of smoking pack-years with abdominal and visceral obesity. Overall obesity measured by body mass index and total body fat percentage did not show such associations. Although current smokers clearly showed significant associations, we could not demonstrate these in past smokers, possibly because of the limited sample size.Conclusions/Significance
Although smokers did not show significant difference in mean body mass index than those who never smoked, they showed more metabolically adverse fat distributions with increasing smoking amounts. This finding suggests that smoking is not beneficial for weight control. Therefore, smoking cessation and avoidance of smoking commencement should be addressed as important public health issues in preventing obesity and related complications. 相似文献74.
The vegetative morphology and life history of Halopteris filicina (Grateloup) Kutzing, collected from Korea, were examined in laboratory culture. Field plants attaining 3–5 cm in height were epilithic, tufted, yellowish-brown, and produced numerous erect axes with alternately distichous branches from compact basal discs. They were cultured under a 12:12 h LD photoperiod at 10°-C, 15°C and 20°C to observe the influence of temperature on reproduction. At 10°C plants grew only vegetatively, whereas at 15°C and 20°C they produced unilocular sporangia. Unispores released from sporangia developed into monoecious, anisogamous gametophytes that formed plurilocular female and male gametangia on the same lateral branches. The zygotes, by fusion of female macrogametes and male microgametes, developed into sporophytes bearing unilocular sporangia, whereas the unfused female gametes germinated parthenogenetically. This species was confirmed to have an isomorphic life history, basically similar to the other species of Sphacelariales. 相似文献
75.
Mayur Nimbadas Devare Yeong Hyeock Kim Joohye Jung Woo Kyu Kang Ki‐Sun Kwon Jeong‐Yoon Kim 《Aging cell》2020,19(6)
Glucose controls the phosphorylation of silent information regulator 2 (Sir2), a NAD+‐dependent protein deacetylase, which regulates the expression of the ATP‐dependent proton pump Pma1 and replicative lifespan (RLS) in yeast. TORC1 signaling, which is a central regulator of cell growth and lifespan, is regulated by glucose as well as nitrogen sources. In this study, we demonstrate that TORC1 signaling controls Sir2 phosphorylation through casein kinase 2 (CK2) to regulate PMA1 expression and cytoplasmic pH (pHc) in yeast. Inhibition of TORC1 signaling by either TOR1 deletion or rapamycin treatment decreased PMA1 expression, pHc, and vacuolar pH, whereas activation of TORC1 signaling by expressing constitutively active GTR1 (GTR1Q65L) resulted in the opposite phenotypes. Deletion of SIR2 or expression of a phospho‐mutant form of SIR2 increased PMA1 expression, pHc, and vacuolar pH in the tor1Δ mutant, suggesting a functional interaction between Sir2 and TORC1 signaling. Furthermore, deletion of TOR1 or KNS1 encoding a LAMMER kinase decreased the phosphorylation level of Sir2, suggesting that TORC1 signaling controls Sir2 phosphorylation. It was also found that Sit4, a protein phosphatase 2A (PP2A)‐like phosphatase, and Kns1 are required for TORC1 signaling to regulate PMA1 expression and that TORC1 signaling and the cyclic AMP (cAMP)/protein kinase A (PKA) pathway converge on CK2 to regulate PMA1 expression through Sir2. Taken together, these findings suggest that TORC1 signaling regulates PMA1 expression and pHc through the CK2–Sir2 axis, which is also controlled by cAMP/PKA signaling in yeast. 相似文献
76.
Bioconjugation of L-3,4-dihydroxyphenylalanine containing protein with a polysaccharide 总被引:1,自引:0,他引:1
Ayyadurai N Prabhu NS Deepankumar K Jang YJ Chitrapriya N Song E Lee N Kim SK Kim BG Soundrarajan N Lee S Cha HJ Budisa N Yun H 《Bioconjugate chemistry》2011,22(4):551-555
We describe the simple bioconjugation strategy in combination of periodate chemistry and unnatural amino acid incorporation. The residue specific incorporation of 3,4-dihydroxy-l-phenylalanine can alter the properties of protein to conjugate into the polymers. The homogeneously modified protein will yield quinone residues that are covalently conjugated to nucleophilic groups of the amino polysaccharide. This novel approach holds great promise for widespread use to prepare protein conjugates and synthetic biology applications. 相似文献
77.
78.
Glioblastoma is an aggressive malignant brain tumor that starts in the brain or spine and frequently recurs after anticancer treatment. The development of an accurate diagnostic system combined with effective cancer therapy is essential to improve prognosis of glioma patients. Peptides, produced from phage display, are attractive biomolecules for glioma treatment because of their biostability, nontoxicity, and small size. In this study, we employed phage display methodology to screen for peptides that specifically recognize the target PKCδ as a novel biomarker for glioma. The phage library screening yielded four different peptides displayed on phages with a 20- to 200-pM Kd value for the recombinant PKCδ catalytic domain. Among these four phage peptides, we selected one to synthesize and tagged it with fluorescein isothiocyanate (FITC) based on the sequence of the PKCδ-binding phage clone. The synthetic peptide showed a relative binding affinity for antibody and localization in the U373 glioma cell. The kinase activity of PKCδ was inhibited by FITC-labeled peptide with an IC50 of 1.4 μM in vitro. Consequently, the peptide found in this study might be a promising therapeutic agent against malignant brain tumor. 相似文献
79.
80.
Il Sang Yoon 《Analytical biochemistry》2010,407(2):205-210
Parkinson’s disease (PD) is a neurodegenerative disease featured by selective loss of substantia nigra neurons. Rotenone administration in animals induces neurodegeneration accompanied by α-synuclein-positive Lewy body-like inclusions, recapturing typical histopathological features of PD. In an effort to screen for small-molecule agents to reverse rotenone-induced cytotoxicity, we developed and validated a sensitive and robust assay with neuroblastoma SK-N-SH cells. This assay was amenable to a high-throughput screening format with Z′ factor of 0.56. Robotic screening of a bioactive compound library led to the identification of carnosic acid that can effectively protect cells from rotenone treatment. Using a high-content image-based assay and Western blot analysis, we demonstrated that carnosic acid protects cells from rotenone stress by significant induction of HSP70 expression. Therefore, the assay reported here can be used to identify novel cytoprotective agents for clinical therapeutics of PD. 相似文献