全文获取类型
收费全文 | 640篇 |
免费 | 31篇 |
国内免费 | 2篇 |
出版年
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 14篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 18篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 40篇 |
2012年 | 52篇 |
2011年 | 31篇 |
2010年 | 36篇 |
2009年 | 22篇 |
2008年 | 39篇 |
2007年 | 27篇 |
2006年 | 32篇 |
2005年 | 30篇 |
2004年 | 26篇 |
2003年 | 21篇 |
2002年 | 26篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 7篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有673条查询结果,搜索用时 15 毫秒
631.
Emergence of novel pandemic viral disease CoVid-19 and its mutational behaviour are alarming. The potential use of nano-biotechnology in combating CoVid-19 is promising. We glean available data to explore such possibility in this short note. 相似文献
632.
Madan L. Gupta 《Journal of biological physics》1973,1(1):17-25
The current literature is critically examined as regards to the applicability of statistical mechanics to the dipole model in order to describe phase transition in biological membranes. The numerical calculations in this context are shown to be speculative and model dependent. Implications of the X-ray diffraction studies on membranes are discussed and it is deduced that only the perpendicular orientation of the dipoles in the polar layer is consistent with the X-ray diffraction data.The author wishes to thank Drs. L. David Roper and E. Keith Hege for many helpful comments. 相似文献
633.
Beta‐turns in beta‐hairpins have been implicated as important sites in protein folding. In particular, two residue β‐turns, the most abundant connecting elements in beta‐hairpins, have been a major target for engineering protein stability and folding. In this study, we attempted to investigate and update the structural and sequence properties of two residue turns in beta‐hairpins with a large data set. For this, 3977 beta‐turns were extracted from 2394 nonhomologous protein chains and analyzed. First, the distribution, dihedral angles and twists of two residue turn types were determined, and compared with previous data. The trend of turn type occurrence and most structural features of the turn types were similar to previous results, but for the first time Type II turns in beta‐hairpins were identified. Second, sequence motifs for the turn types were devised based on amino acid positional potentials of two‐residue turns, and their distributions were examined. From this study, we could identify code‐like sequence motifs for the two residue beta‐turn types. Finally, structural and sequence properties of beta‐strands in the beta‐hairpins were analyzed, which revealed that the beta‐strands showed no specific sequence and structural patterns for turn types. The analytical results in this study are expected to be a reference in the engineering or design of beta‐hairpin turn structures and sequences. Proteins 2014; 82:1721–1733. © 2014 Wiley Periodicals, Inc. 相似文献
634.
635.
636.
T. S. Rana Kamalesh S. Mahar Madan M. Pandey S. K. Srivastava A. K. S. Rawat 《Physiology and Molecular Biology of Plants》2013,19(2):231-237
In the present study, molecular (DAMD and ISSR) and chemical (α and β-asarone contents) markers were used to characterize the A. calamus genotypes procured from different parts of India. The cumulative analysis carried out for both DAMD and ISSR markers revealed 24.71 % polymorphism across all genotypes of A. calamus. The clustering patterns of the genotypes in the UPGMA tree showed that the genotypes are diverse, and did not show any specific correlation with their geographical provenances, reflecting the low level of genetic diversity and a high genetic differentiation among the genotypes from the same localities. All the 27 genotypes of A. calamus were also analyzed for α and β-asarone contents, and percentage of essential oil. The genotype (Ac13) from Kullu (Himachal Pradesh) showed maximum (9.5 %) percentage of oil, whereas corresponding minimum (2.8 %) was obtained from the genotypes from Pangthang (Sikkim). Similarly, the highest α and β-asarone contents (16.82 % and 92.12 %) were obtained from genotypes from Renuka (Himachal Pradesh) and Udhampur (Jammu & Kashmir), while lowest α and β-asarone contents (0.83 % and 65.96 %) resulted from Auranwa (Uttar Pradesh) and Pangthang (Sikkim) genotypes, respectively. A. calamus harbours tremendous economic value, and it is therefore, important to identify the genotypes with low α and β-asarone contents for its commercial utilization. Further, this study will help in evaluation and documentation of a large number of diverse genotypes for their value traits. 相似文献
637.
Pankaj Kumar Jain Vijai K. Gupta Hardik Pathak Madan Lowry D. P. Jaroli 《World journal of microbiology & biotechnology》2010,26(8):1419-1426
The biodegradability of petroleum hydrocarbons such as polycyclic aromatic hydrocarbons (PAHs) and n-branched alkanes etc. of 2T engine oil were studied in aqueous media using bacterial strain isolated from petroleum contaminated
soil of high altitude. Out of five petroleum degrading bacterial strain one of the most growing bacteria was identified as
Enterobacter strain by morphological, physiological, biochemical and partial sequencing of 16S rDNA. This strain was capable of degrading
75 ± 3% of n-alkanes, 32 ± 5% PAHs, and the abiotic loss was 24 ± 6% during 10 days incubation period. 85 ± 2% of n-alkanes and 51 ± 3% PAHs were biodegraded in 20 days. The abiotic loss during this period was 15 ± 3%. In 30 days of incubation
period 98% ± 1% n-alkanes and 75 ± 3% PAHs were degraded. As expected abiotic losses were smaller with increasing long chain alkanes and PAH’s
concentration. An increment in oil degradation was correlated to an increase in cell number indicating that the bacterial
isolate was responsible for the oil degradation. The hydrocarbon contents were measured by Shimadzu QP-2000 Gas chromatography/mass
spectrometry by ULBON HR-1 column. 相似文献
638.
L Akshayaa Thangavelu Lakshmi Ezhilarasan Devaraj Anitha Roy S Raghunandhakumar P Sivaperumal Sheba David Kamal Dua Dinesh Kumar Chellappan 《Bioinformation》2020,16(11):878
Design and development of effective anti-virals in combating CoVid-19 is a great challenge worldwide. Known drugs such as chloroquine, lopinavir, favipiravir and remdesivir are used in the management of CoVid - 19. It is known that Ivermectin and remdesivir both are effective against filoviruses, paramyxo viruses. Available data also shows that ivermectin and remedesivir repress the replication of SARS-CoV-2. Thus, we document the potential use of ivermectin and remdesivir in the management of CoVid -19. 相似文献
639.