全文获取类型
收费全文 | 662篇 |
免费 | 45篇 |
国内免费 | 1篇 |
出版年
2024年 | 3篇 |
2023年 | 3篇 |
2022年 | 16篇 |
2021年 | 30篇 |
2020年 | 12篇 |
2019年 | 22篇 |
2018年 | 24篇 |
2017年 | 29篇 |
2016年 | 43篇 |
2015年 | 42篇 |
2014年 | 40篇 |
2013年 | 66篇 |
2012年 | 70篇 |
2011年 | 61篇 |
2010年 | 29篇 |
2009年 | 33篇 |
2008年 | 33篇 |
2007年 | 28篇 |
2006年 | 20篇 |
2005年 | 13篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1973年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有708条查询结果,搜索用时 171 毫秒
111.
Chui-Yao Teh Noor Azmi Shaharuddin Chai-Ling Ho Maziah Mahmood 《Acta Physiologiae Plantarum》2016,38(6):151
Salinity has been shown to be a major factor contributing to low nitrogen availability in plants. To verify the changes in nitrogen metabolism activity as affected by the exogenous application of proline under salt stress and its relation to salt tolerance, in vitro rice shoot apices were used as a model to study the growth performance and changes in nitrogen assimilation activities in two Malaysian rice cultivars MR 220 and MR 253. Results revealed that salt stress greatly reduced the plant height, shoot nitrate (NO3 ?) content, shoot glutamine synthetase (GS), and root nitrate reductase (NR) activities in both cultivars. Supplementation of proline significantly increased the plant height, number of roots, root NO3 ? content, root NR, and root GS activities under salt stress in both cultivars with greater enhancement in MR 253 than MR 220. The results also indicated that MR 253 possessed higher nitrite reductase (NiR) and glutamate synthase (NADH–GOGAT) activities as compared with MR 220 in all tested treatments. It was suggested that the NO3 ? content, NR, and GS activities played important roles in regulating nitrogen metabolism under salt stress. Taken together, it was concluded that the ability of proline in mitigating salt stress-induced damages was correlated with the changes in nitrogen assimilation activities. 相似文献
112.
113.
114.
115.
116.
117.
En route to economical eco‐friendly solvent system in enhancing sustainable recovery of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) copolymer
下载免费PDF全文
![点击此处可从《Engineering in Life Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nik Murniati Nik Man Irdahayu Kannusamy Shantini Kai‐Hee Huong Sevakumaran Vigneswari Nursolehah Abdul Aziz Mohd. Noor Mohd. Azizan Al‐Ashraf Abdullah Amirul 《Engineering in Life Science》2017,17(9):1050-1059
Separation of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) [P(3HB‐co‐4HB)] from bacterial cell matter is a critical step in the downstream process with respect to material quality and eco‐balance as P(3HB‐co‐4HB) is widely used for biomedical applications. Therefore, an efficient and eco‐based extraction of P(3HB‐co‐4HB) using a combination of NaOH and Lysol in digesting the non‐polymeric cell material (NPCM) digestion is developed. The NaOH and Lysol show synergistic influence on the copolymer extraction at a high purity and recovery of 97 and 98 wt% respectively. The optimized cell digestion method was found applicable to a vast batch of cells containing copolymers from various 4HB monomer compositions. At the largest extraction volume of 100 L, P(3HB‐co‐4HB) with a purity of 89 wt% was extracted with a maximum recovery of 90 wt%. The method developed has also eliminated the cell pretreatment step. The extraction method developed in this research has not only produced an economic and efficient copolymer recovery but has also retained the copolymer quality, in term of its molecular weight and thermal properties. It demonstrates a practical and promising downstream processing method in recovering the copolymer effectively from the bacterial biomass. 相似文献
118.
119.
Naqvi RA Hussain A Raish M Noor A Shahid M Sarin R Kukreti H Khan NJ Ahmad S Deo SV Husain SA Pasha ST Basir SF Shukla NK 《DNA and cell biology》2008,27(9):517-525
Even after tremendous molecular studies, early detection,more accurate and sensitive diagnosis, and prognosis of breast cancer appear to be a riddle so far. To stab the enigma, this study is designed to envisage DNA methylation signatures as cancer-specific and stage-specific biomarkers in Indian patients. Rigorous review of scattered scientific reports on aberrant DNA methylation helped us to select and analyze a potential tumor suppressor gene pair (FHIT and p16 genes) in breast cancer patients. Methylation signatures from 232 primary sporadic breast cancer patients were pinpointed by methylation-specific PCR (MSP). To increase the sensitivity, we combined both MSP and expression studies (RT-PCR and Northern blotting) in a reproducible manner. Statistical analysis illustrated that hypermethylation of FHIT gene ( p < 0.0001) and p16 gene ( p=0.04) may be used as a potential diagnostic marker to diagnose the early and locally advanced stages of breast cancer. Additionally, the study authenticates the dependency of methylation and expressional loss of p16 gene on FHIT gene silencing. This observation not only describes the severity of disease when both genes are silenced but also drives to speculate the molecular cross talk between two genes or genetic pathways dictated by them separately. 相似文献
120.
Matsuno Y Deguchi J Hirasawa Y Ohyama K Toyoda H Hirobe C Ekasari W Widyawaruyanti A Zaini NC Morita H 《Bioorganic & medicinal chemistry letters》2008,18(13):3774-3777
Two new cassane-type diterpenes, sucutiniranes A (1) and B (2), have been isolated from the seeds of Bowdichia nitida together with 6alpha-acetoxyvouacapane (3) and 6alpha,7beta-diacetoxyvouacapane (4), and the structures of 1 and 2 were elucidated by using 2D NMR data and chemical correlations. Sucutinirane A (1) and 3 showed a moderate cytotoxicity against human colon carcinoma COLO201 cells, and 6alpha,7beta-diacetoxyvouacapane (4) showed in vitro antiplasmodial activity against parasite Plasmodium falciparum 3D7. 相似文献