全文获取类型
收费全文 | 851篇 |
免费 | 160篇 |
国内免费 | 5篇 |
出版年
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 20篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 26篇 |
2015年 | 49篇 |
2014年 | 25篇 |
2013年 | 49篇 |
2012年 | 70篇 |
2011年 | 61篇 |
2010年 | 38篇 |
2009年 | 37篇 |
2008年 | 44篇 |
2007年 | 42篇 |
2006年 | 48篇 |
2005年 | 39篇 |
2004年 | 31篇 |
2003年 | 34篇 |
2002年 | 29篇 |
2001年 | 24篇 |
2000年 | 28篇 |
1999年 | 15篇 |
1998年 | 10篇 |
1997年 | 17篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 12篇 |
1993年 | 15篇 |
1992年 | 24篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 20篇 |
1988年 | 17篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1979年 | 8篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有1016条查询结果,搜索用时 31 毫秒
181.
Lu Yuyun Voon Marilyn Kai Wen Chua Jian-Yong Huang Dejian Lee Pin-Rou Liu Shao-Quan 《Applied microbiology and biotechnology》2017,101(21):7853-7863
Applied Microbiology and Biotechnology - This is a first study on using two non-Saccharomyces yeasts, Torulaspora delbrueckii Biodiva and Pichia kluyveri FrootZen to produce durian wine via... 相似文献
182.
Fisetin provides antidepressant effects by activating the tropomyosin receptor kinase B signal pathway in mice
下载免费PDF全文
![点击此处可从《Journal of neurochemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yamin Wang Bin Wang Jiaqi Lu Haixia Shi Siyi Gong Yufan Wang Ronald C. Hamdy Balvin H. L. Chua Lingli Yang Xingshun Xu 《Journal of neurochemistry》2017,143(5):561-568
183.
Xiaocong Tian Jun Jin Shangqin Yuan Chee Kai Chua Shu Beng Tor Kun Zhou 《Liver Transplantation》2017,7(17)
Three‐dimensional (3D) printing, a layer‐by‐layer deposition technology, has a revolutionary role in a broad range of applications. As an emerging advanced fabrication technology, it has drawn growing interest in the field of electrochemical energy storage because of its inherent advantages including the freeform construction and controllable 3D structural prototyping. This article focuses on the topic of 3D‐printed electrochemical energy storage devices (EESDs), which bridge advanced electrochemical energy storage and future additive manufacturing. Basic 3D printing systems and material considerations are described to provide a fundamental understanding of printing technologies for the fabrication of EESDs. The performance metrics of 3D‐printed EESDs are then given and the related performance optimization strategies are discussed. Next, the recent advances of 3D‐printed EESDs, including sandwich‐type and in‐plane architectures, are summarized. Conclusions and future perspectives with some unique challenges and important directions are then discussed. It can be expected that, with the help of 3D printing technology, the development of advanced electrochemical energy storage systems will be greatly promoted. 相似文献
184.
185.
Siu T Li Y Nagasawa J Liang J Tehrani L Chua P Jones RE Defeo-Jones D Barnett SF Robinson RG 《Bioorganic & medicinal chemistry letters》2008,18(14):4191-4194
This letter details the attenuation of hERG in a class of Akt inhibitors through heteroatom insertions into aromatic rings. The development of a cell-active dual Akt 1 and 2 inhibitors devoid of hERG activity is discussed using structure–activity relationships. 相似文献
186.
In a previous study, the conserved arginine residue at position 306 of Streptomyces clavuligerus deacetoxycephalsoporin C synthase (scDAOCS), when mutated to leucine, resulted in 191% increase in converting ampicillin to its expanded cephalosporin moiety compared with that of the wild-type enzyme. However, the role of this residue in eliciting the improved enzymatic activity is not well understood. In this study, probing the molecular basis of amino acid substitutions at position 306 has underscored its importance for engineering various improvements in the ring expansion activity. Structural modeling using SwissPdbViewer revealed that R306 is surrounded by a hydrophobic cleft formed by residues Y184, L186, W297, I298, and V303. Hence, the improved activity achieved by the R306L mutation was probably because of better hydrophobic packing in this region. To evaluate the role of amino acids at position 306 of scDAOCS and its influence on the molecular status of the enzyme at this locality, alteration to 18 other amino acids was done by site-directed mutagenesis. The effects of each substitution on the enzyme activity were determined by bioassay using penicillin substrates: ampicillin, penicillin G, phenethicillin, and carbenicillin. Results obtained showed a drastic reduction in enzyme activity when R306 was replaced with charged or polar residues, thus emphasizing the importance of hydrophobic packing around this site. The bioassay results also illustrated that apart from leucine, substitutions to nonpolar residues, isoleucine and methionine, were able to improve the ampicillin conversion activity of scDAOCS by 168 and 113% of the wild-type enzyme activity, respectively. Similar trend of effects from each mutation was also observed for penicillin G, phenethicillin, and carbenicillin conversions. The enhanced enzyme activities were supported by spectrophotometric assay indicating that all these mutants have lower K(m) values (R306L: 1.09 mM; R306I: 2.64 mM; R306M: 5.68 mM) than the wild-type enzyme (8.33 mM), resulting in improvement in the enzyme's substrate binding affinity. Hence, this mutational study of amino acids situated at 306 of scDAOCS has provided a better understanding of the significance of specific amino acid residues at this position which can improve its ring-expansion activity when given a plethora of beta-lactam substrates to generate corresponding, possibly new, cephalosporins. 相似文献
187.
188.
Quantitative identification of teratoma tissues formed by human embryonic stem cells with TeratomEye
Steve Kah Weng Oh Pauline Chua Koh Lin Foon Emily Ng Angela Chin Andre Boon Hwa Choo Rajagopalan Srinivasan 《Biotechnology letters》2009,31(5):653-658
An automated vision system, TeratomEye, was developed for the identification of three representative tissue types: muscle,
gut and neural epithelia which are commonly found in teratomas formed from human embryonic stem cells. Muscle tissue, a common
structure was identified with an accuracy of 90.3% with high specificity and sensitivity greater than 90%. Gut epithelia were
identified with an accuracy of 87.5% with specificity and sensitivity greater than 80%. Neural epithelia which were the most
difficult structures to distinguish gave an accuracy of 47.6%. TeratomEye is therefore useful for the automated identification
of differentiated tissues in teratoma sections. 相似文献
189.
Olivier Lefebvre Wai K. Ooi Zhe Tang Md. Abdullah-Al-Mamun Daniel H.C. Chua How Y. Ng 《Bioresource technology》2009,100(20):4907-4910
Microbial fuel cells (MFCs) are considered as a promising way for the direct extraction of biochemical energy from biomass into electricity. However, scaling up the process for practical applications and mainly for wastewater treatment is an issue because there is a necessity to get rid of unsustainable platinum (Pt) catalyst. In this study, we developed a low-cost cathode for a MFC making use of sputter-deposited cobalt (Co) as the catalyst and different types of cathode architecture were tested in a single-chambered air-cathode MFC. By sputtering the catalyst on the air-side of the cathode, increased contact with ambient oxygen significantly resulted in higher electricity generation. This outcome was different from previous studies using conventionally-coated Pt cathodes, which was due to the different technology used. 相似文献
190.