全文获取类型
收费全文 | 1459篇 |
免费 | 102篇 |
专业分类
1561篇 |
出版年
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 10篇 |
2018年 | 21篇 |
2017年 | 22篇 |
2016年 | 24篇 |
2015年 | 66篇 |
2014年 | 67篇 |
2013年 | 72篇 |
2012年 | 120篇 |
2011年 | 116篇 |
2010年 | 70篇 |
2009年 | 57篇 |
2008年 | 93篇 |
2007年 | 83篇 |
2006年 | 103篇 |
2005年 | 93篇 |
2004年 | 80篇 |
2003年 | 74篇 |
2002年 | 85篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 18篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 13篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 13篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 12篇 |
1976年 | 3篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1968年 | 3篇 |
1964年 | 3篇 |
排序方式: 共有1561条查询结果,搜索用时 15 毫秒
101.
The list of genetic diseases caused by mutations that affect mRNA translation is rapidly growing. Although protein synthesis is a fundamental process in all cells, the disease phenotypes show a surprising degree of heterogeneity. Studies of some of these diseases have provided intriguing new insights into the functions of proteins involved in the process of translation; for example, evidence suggests that several have other functions in addition to their roles in translation. Given the numerous proteins involved in mRNA translation, it is likely that further inherited diseases will turn out to be caused by mutations in genes that are involved in this complex process. 相似文献
102.
Genome sequencing and analysis of the versatile cell factory Aspergillus niger CBS 513.88 总被引:1,自引:0,他引:1
Pel HJ de Winde JH Archer DB Dyer PS Hofmann G Schaap PJ Turner G de Vries RP Albang R Albermann K Andersen MR Bendtsen JD Benen JA van den Berg M Breestraat S Caddick MX Contreras R Cornell M Coutinho PM Danchin EG Debets AJ Dekker P van Dijck PW van Dijk A Dijkhuizen L Driessen AJ d'Enfert C Geysens S Goosen C Groot GS de Groot PW Guillemette T Henrissat B Herweijer M van den Hombergh JP van den Hondel CA van der Heijden RT van der Kaaij RM Klis FM Kools HJ Kubicek CP van Kuyk PA Lauber J 《Nature biotechnology》2007,25(2):221-231
103.
Activation tagging using the En-I maize transposon system in Arabidopsis 总被引:21,自引:0,他引:21
Marsch-Martinez N Greco R Van Arkel G Herrera-Estrella L Pereira A 《Plant physiology》2002,129(4):1544-1556
A method for the generation of stable activation tag inserts was developed in Arabidopsis using the maize (Zea mays) En-I transposon system. The method employs greenhouse selectable marker genes that are useful to efficiently generate large populations of insertions. A population of about 8,300 independent stable activation tag inserts has been produced. Greenhouse-based screens for mutants in a group of plants containing about 2,900 insertions revealed about 31 dominant mutants, suggesting a dominant mutant frequency of about 1%. From the first batch of about 400 stable insertions screened in the greenhouse, four gain-in-function, dominant activation-tagged, morphological mutants were identified. A novel gain-in-function mutant called thread is described, in which the target gene belongs to the same family as the YUCCA flavin-mono-oxygenase that was identified by T-DNA activation tagging. The high frequency of identified gain-in-function mutants in the population suggests that the En-I system described here is an efficient strategy to saturate plant genomes with activation tag inserts. Because only a small number of primary transformants are required to generate an activation tag population, the En-I system appears to be an attractive alternative to study plant species where the present transformation methods have low efficiencies. 相似文献
104.
Hu X Hansen BM Eilenberg J Hendriksen NB Smidt L Yuan Z Jensen GB 《FEMS microbiology letters》2004,233(1):45-52
The plasmid pHT73 containing cry1Ac and tagged with an erythromycin resistance gene was transferred from Bacillus thuringiensis subspecies kurstaki KT0 to several Bacillus cereus group strains by conjugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and phase contrast microscopy showed that the transconjugants containing plasmid pHT73 could express Cry1Ac toxin and produce bipyramidal crystalline inclusion bodies during sporulation. The study demonstrated that pHT73 could be transferred to B. thuringiensis subsp. kurstaki, several B. cereus strains and Bacillus mycoides. Under non-selective conditions, the stability of the pHT73 plasmid in the transconjugants was found to be 58.2-100% after 100 generations and 4-96% after 200 generations. The variations are mainly caused by the choice of receptor strain. 相似文献
105.
UCP3 has been postulated to function in the defense against lipid-induced oxidative muscle damage (lipotoxicity). We explored this hypothesis during cachexia in rats (zymosan-induced sepsis), a condition characterized by increased oxidative stress and supply of fatty acids to the muscle. Muscle UCP3 protein content was increased 2, 6 and 11 days after zymosan injection. Plasma FFA levels were increased at day 2, but dropped below control levels on days 6 and 11. Muscular levels of the lipid peroxidation byproduct 4-hydroxy-2-nonenal (4-HNE) were increased at days 6 and 11 in zymosan-treated rats, supporting a role for UCP3 in modulating lipotoxicity during cachexia. 相似文献
106.
Inge Everaert Antien Mooyaart Audrey Baguet Ana Zutinic Hans Baelde Eric Achten Youri Taes Emile De Heer Wim Derave 《Amino acids》2011,40(4):1221-1229
Carnosine is found in high concentrations in skeletal muscles, where it is involved in several physiological functions. The
muscle carnosine content measured within a population can vary by a factor 4. The aim of this study was to further characterize
suggested determinants of the muscle carnosine content (diet, gender and age) and to identify new determinants (plasma carnosinase
activity and testosterone). We investigated a group of 149 healthy subjects, which consisted of 94 men (12 vegetarians) and
55 women. Muscle carnosine was quantified in M. soleus, gastrocnemius and tibialis anterior using magnetic resonance proton
spectroscopy and blood samples were collected to determine CNDP1 genotype, plasma carnosinase activity and testosterone concentrations. Compared to women, men have 36, 28 and 82% higher
carnosine concentrations in M. soleus, gastrocnemius and tibialis anterior muscle, respectively, whereas circulating testosterone
concentrations were unrelated to muscle carnosine levels in healthy men. The carnosine content of the M. soleus is negatively
related to the subjects’ age. Vegetarians have a lower carnosine content of 26% in gastrocnemius compared to omnivores. In
contrast, there is no difference in muscle carnosine content between omnivores with a high or low ingestion of β-alanine.
Muscle carnosine levels are not related to the polymorphism of the CNDP1 gene or to the enzymatic activity of the plasma carnosinase. In conclusion, neither CNDP1 genotype nor the normal variation in circulating testosterone levels affects the muscular carnosine content, whereas vegetarianism,
female gender and increasing age are the factors associated with reduced muscle carnosine stores. 相似文献
107.
Julija Romanuka Heidi van den Bulke Robert Kaptein Rolf Boelens Gert E. Folkers 《Protein expression and purification》2009,67(2):104-112
NMR studies of structural aspects of allosteric regulation by the Lac repressor requires overexpression and isotope labeling of the protein. The size of the repressor makes it a challenging target, putting constraints on both expression conditions and sample preparation methods to overcome problems associated with studies of larger proteins by NMR. We optimized protocols for the production of deuterated functionally active thermostable dimeric Lac repressor and its core domain mutants. The Lac repressor core domain has never been obtained as a recombinant protein, possibly due to the observed toxicity to the host cells. We overcame the core domain induced toxicity by co-expression of this domain with the full length Lac repressor, combined with a stringent control of culture conditions. Significant overexpression was only obtained if during all stages of pre-culturing the bacteria were kept in their exponential growth phase at low density. The sensitivity of NMR measurements is dramatically affected by buffer conditions; we therefore used a thermofluor buffer optimization screen to determine the optimal buffer conditions. The combined thermofluor and NMR screening method yielded thermostable fully functional Lac repressor domain samples suitable for high-resolution NMR studies. The optimized procedures to adapt Escherichia coli to growth in D2O, to overcome toxicity, and to optimize protein sample conditions provides a broad range of universally applicable techniques for production of larger proteins for NMR spectroscopy. 相似文献
108.
Sara Borin Francesca Mapelli Eleonora Rolli Bongkeun Song Craig Tobias Markus C. Schmid Gert J. De Lange Gert J. Reichart Stefan Schouten Mike Jetten Daniele Daffonchio 《Extremophiles : life under extreme conditions》2013,17(2):289-299
To extend the knowledge of anaerobic ammonium oxidation (anammox) habitats, bacterial communities were examined in two hypersaline sulphidic basins in Eastern Mediterranean Sea. The 2 m thick seawater–brine haloclines of the deep anoxic hypersaline basins Bannock and L’Atalante were sampled in intervals of 10 cm with increasing salinity. 15N isotope pairing incubation experiments showed the production of 29N2 and 30N2 gases in the chemoclines, ranging from 6.0 to 9.2 % salinity of the L’Atalante basin. Potential anammox rates ranged from 2.52 to 49.65 nmol N2 L?1 day?1 while denitrification was a major N2 production pathway, accounting for more than 85.5 % of total N2 production. Anammox-related 16S rRNA genes were detected along the L’Atalante and Bannock haloclines up to 24 % salinity, and the amplification of the hydrazine synthase genes (hzsA) further confirmed the presence of anammox bacteria in Bannock. Fluorescence in situ hybridisation and sequence analysis of 16S rRNA genes identified representatives of the marine anammox genus ‘Candidatus Scalindua’ and putatively new operational taxonomic units closely affiliated to sequences retrieved in marine environments that have documented anammox activity. ‘Scalindua brodae’ like sequences constituted up to 84.4 % of the sequences retrieved from Bannock. The anammox community in L’Atalante was different than in Bannock and was stratified according to salinity increase. This study putatively extends anammox bacterial habitats to extremely saline sulphidic ecosystems. 相似文献
109.
Georgakopoulou S van der Zwan G Bassi R van Grondelle R van Amerongen H Croce R 《Biochemistry》2007,46(16):4745-4754
In this work we modeled the circular dichroism (CD) spectrum of LHCII, the main light harvesting antenna of photosystem II of higher plants. Excitonic calculations are performed for a monomeric subunit, taken from the crystal structure of trimeric LHCII from spinach [Liu, Z. F., Yan, H. C., Wang, K. B., Kuang, T. Y., Zhang, J. P., Gui, L. L., An, X. M., and Chang, W. R. (2004) Nature 428, 287-292]. All of the major features of the CD spectrum above 450 nm are satisfactorily reproduced, and possible orientations of the Chl and carotenoid transition dipole moments are identified. The obtained modeling parameters are used to simulate the CD spectra of two complexes with altered pigment composition: a mutant lacking Chls a 611-612 and a complex lacking the carotenoid neoxanthin. By removing the relevant pigment(s) from the structure, we are able to reproduce their spectra, which implies that the alteration does not disturb the overall structure. The CD spectrum of trimeric LHCII shows a reversed relative intensity of the two negative bands around 470 and 490 nm as compared to monomeric LHCII. The simulations reproduce this reversal, indicating that it is mainly due to interactions between chromophores in different monomeric subunits, and the trimerization does not induce observable changes in the monomeric structure. Our simulated spectrum resembles one of two different trimeric CD spectra reported in literature. We argue that the differences in the experimental trimeric CD spectra are caused by changes in the strength of the monomer-monomer interactions due to the differences in detergents used for the purification of the complexes. 相似文献
110.
Gebruers K Brijs K Courtin CM Fierens K Goesaert H Rabijns A Raedschelders G Robben J Sansen S Sørensen JF Van Campenhout S Delcour JA 《Biochimica et biophysica acta》2004,1696(2):213-221
Two types of proteinaceous endoxylanase inhibitors occur in different cereals, i.e. the TAXI [Triticum aestivum endoxylanase inhibitor]-type and XIP [endoxylanase inhibiting protein]-type inhibitors. The present paper focuses on the TAXI-type proteins and deals with their structural characteristics and the identification, characterisation and heterologous expression of a TAXI gene from wheat. In addition, to shed light on the mechanism by which TAXI-type endoxylanase inhibitors work, the enzyme specificity, the optimal conditions for maximal inhibition activity, the molar complexation ratio and the inhibition kinetics of the inhibitors are explained and the effect of mutations of an endoxylanase on the inhibition by TAXIs is discussed. 相似文献