全文获取类型
收费全文 | 929篇 |
免费 | 54篇 |
专业分类
983篇 |
出版年
2022年 | 8篇 |
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 19篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 49篇 |
2014年 | 50篇 |
2013年 | 46篇 |
2012年 | 72篇 |
2011年 | 62篇 |
2010年 | 38篇 |
2009年 | 43篇 |
2008年 | 49篇 |
2007年 | 50篇 |
2006年 | 47篇 |
2005年 | 43篇 |
2004年 | 52篇 |
2003年 | 36篇 |
2002年 | 39篇 |
2001年 | 16篇 |
2000年 | 7篇 |
1999年 | 14篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有983条查询结果,搜索用时 13 毫秒
31.
Tina L. Yuan Arnaud Amzallag Rachel Bagni Ming Yi Shervin Afghani William Burgan Nicole Fer Leslie A. Strathern Katie Powell Brian Smith Andrew M. Waters David Drubin Ty Thomson Rosy Liao Patricia Greninger Giovanna T. Stein Ellen Murchie Eliane Cortez Frank McCormick 《Cell reports》2018,22(7):1889-1902
32.
Eliane V. Wolf Annett Zei?ler Oliver Vosyka Evelyn Zeiler Stephan Sieber Steven H. L. Verhelst 《PloS one》2013,8(8)
Rhomboids are intramembrane serine proteases that play diverse biological roles, including some that are of potential therapeutical relevance. Up to date, rhomboid inhibitor assays are based on protein substrate cleavage. Although rhomboids have an overlapping substrate specificity, substrates cannot be used universally. To overcome the need for substrates, we developed a screening assay using fluorescence polarization activity-based protein profiling (FluoPol ABPP) that is compatible with membrane proteases. With FluoPol ABPP, we identified new inhibitors for the E. coli rhomboid GlpG. Among these was a structural class that has not yet been reported as rhomboid inhibitors: β-lactones. They form covalent and irreversible complexes with the active site serine of GlpG. The presence of alkyne handles on the β-lactones also allowed activity-based labeling. Overall, these molecules represent a new scaffold for future inhibitor and activity-based probe development, whereas the assay will allow inhibitor screening of ill-characterized membrane proteases. 相似文献
33.
Felipe de Oliveira Fernandes Sérgio Ricardo de Oliveira Vitor Klein Marcella Araújo do Amaral Carneiro Pio Colepicolo Eliane Marinho-Soriano 《Journal of applied phycology》2017,29(2):695-705
The genus Gracilaria is one of the most important sources of agar in the world. In Brazil, Gracilaria birdiae is the main commercially exploited species; however, overexploitation has contributed to the depletion of natural beds. In order to obtain more information so as to consolidate G. birdiae cultivation, studies under laboratory (indoor and outdoor) and field (sea and shrimp pond) conditions were conducted to evaluate the effects of fertilizer pulses on biomass and relative growth rate (RGR) of this species. The following nutrient sources used were (T1) shrimp-pond effluent, (T2) fertilizer for aquarium plants (Mbreda), and (T3) fertilizer extract of Ascophyllum nodosum (Acadian). Significant differences for growth were recorded over time for all treatments in both outdoor and field conditions (p < 0.001). The highest RGRs were recorded for treatments that used pulses of commercial fertilizers (T2 and T3) and the lowest for treatment using shrimp-pond effluent pulses (T1). The analysis of the nutrient content in tissue also showed a relationship between growth and nitrogen and phosphorus accumulation in the algal tissues. The N/P ratio indicated a significant effect on the growth of G. birdiae and the highest RGRs were registered for seedlings with a N/P ratio ≥16 (T2 and T3). In conclusion, the best results were recorded for the Mbreda and Acadian commercial fertilizers. However, although no significant differences were detected between growth and the two fertilizers (T2 and T3), the seedlings cultivated under Acadian pulses showed a better performance against environmental stress caused by reduced salinity. 相似文献
34.
35.
Isabel C.M. Fensterseifer Mário R. Felício Eliane S.F. Alves Marlon H. Cardoso Marcelo D.T. Torres Carolina O. Matos Osmar N. Silva Timothy K. Lu Maurício V. Freire Natan C. Neves Sónia Gonçalves Luciano M. Lião Nuno C. Santos William F. Porto Cesar de la Fuente-Nunez Octavio L. Franco 《生物化学与生物物理学报:生物膜》2019,1861(7):1375-1387
Infections caused by Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa foremost among them, constitute a major worldwide health problem. Bioinformatics methodologies are being used to rationally design new antimicrobial peptides, a potential alternative for treating these infections. One of the algorithms used to develop antimicrobial peptides is the Joker, which was used to design the peptide PaDBS1R6. This study evaluates the antibacterial activities of PaDBS1R6 in vitro and in vivo, characterizes the peptide interaction to target membranes, and investigates the PaDBS1R6 structure in contact with mimetic vesicles. Moreover, we demonstrate that PaDBS1R6 exhibits selective antimicrobial activity against Gram-negative bacteria. In the presence of negatively charged and zwitterionic lipids the structural arrangement of PaDBS1R6 transits from random coil to α-helix, as characterized by circular dichroism. The tertiary structure of PaDBS1R6 was determined by NMR in zwitterionic dodecylphosphocholine (DPC) micelles. In conclusion, PaDBS1R6 is a candidate for the treatment of nosocomial infections caused by Gram-negative bacteria, as template for producing other antimicrobial agents. 相似文献
36.
Borges E Vuaden FC Cognato Gde P Fauth Mda G Bonan CD Turcato G Rossi IC Dias RD 《Journal of experimental zoology. Part A, Comparative experimental biology》2004,301(11):891-897
In the present study, the glucose concentration in the haemolymph and glycogen levels were determined in the various body parts of the Helix aspersa snail after feeding lettuce ad libitum and after various periods of starvation. To characterize the effect of starvation on nucleotidase activity, enzyme assays were performed on membranes of the nervous ganglia and digestive gland. Results demonstrated the maintenance of the haemolymph glucose concentration for up to 30 days of starvation, probably due to the consumption of glycogen from the mantle. In the nervous ganglia, depletion of glycogen occurs progressively during the different periods of starvation. No significant changes were observed on ATP and ADP hydrolysis in the membranes of nervous ganglia and no alterations in Ca2+ -ATPase and Mg2+ -ATPase occurred in the membranes of the digestive gland of H. aspersa during the different periods of starvation. Although there were no changes in the enzyme activities during starvation, they could be modulated by effectors in situ with concomitant changes in products/reactants during starvation. 相似文献
37.
38.
Rapid quantitative detection of Listeria monocytogenes in meat products by real-time PCR 总被引:2,自引:0,他引:2
Rodríguez-Lázaro D Jofré A Aymerich T Hugas M Pla M 《Applied and environmental microbiology》2004,70(10):6299-6301
We describe a quick and simple method for the quantitative detection of Listeria monocytogenes in meat products. This method is based on filtration, Chelex-100-based DNA purification, and real-time PCR. It can detect as few as 100 CFU/g and quantify as few as 1,000 CFU/g, with excellent accuracy compared to that of the plate count method. Therefore, it is a promising alternative for the detection of L. monocytogenes in meat products. 相似文献
39.
Ferreira EO Salvador MJ Pral EM Alfieri SC Ito IY Dias DA 《Zeitschrift für Naturforschung. C, Journal of biosciences》2004,59(7-8):499-505
A new aurone 1 and two known substances, aurantiamide acetate (2) and tiliroside (3), were isolated from the ethanolic extract of Gomphrena agrestis. The structural determination of 1 was based on spectroscopic and spectrometric data. The substance was defined as (E)-3'-O-beta-D-glucopyranosyl-4,5,6,4'-tetrahydroxy-7,2'-dimethoxyaurone. Biological activity of the ethanolic crude extract and isolated compounds against bacteria, fungi and Leishmania amazonensis amastigotes was evaluated. This appears to be the first report documenting aurone and aurantiamide compounds in the Amaranthaceae family. In the evaluation of biological activity the ethanolic extract of G. agrestis and compounds 1, 2, and 3 were shown to be active mainly against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. 相似文献
40.