全文获取类型
收费全文 | 23711篇 |
免费 | 2032篇 |
国内免费 | 2篇 |
出版年
2021年 | 181篇 |
2020年 | 138篇 |
2019年 | 166篇 |
2018年 | 408篇 |
2017年 | 426篇 |
2016年 | 465篇 |
2015年 | 427篇 |
2014年 | 534篇 |
2013年 | 860篇 |
2012年 | 1510篇 |
2011年 | 1646篇 |
2010年 | 883篇 |
2009年 | 613篇 |
2008年 | 1415篇 |
2007年 | 1456篇 |
2006年 | 1393篇 |
2005年 | 1253篇 |
2004年 | 1219篇 |
2003年 | 1119篇 |
2002年 | 1141篇 |
2001年 | 858篇 |
2000年 | 970篇 |
1999年 | 475篇 |
1998年 | 263篇 |
1997年 | 210篇 |
1996年 | 248篇 |
1995年 | 225篇 |
1994年 | 203篇 |
1993年 | 214篇 |
1992年 | 217篇 |
1991年 | 188篇 |
1990年 | 192篇 |
1989年 | 181篇 |
1988年 | 177篇 |
1987年 | 173篇 |
1986年 | 152篇 |
1985年 | 207篇 |
1984年 | 221篇 |
1983年 | 179篇 |
1982年 | 230篇 |
1981年 | 199篇 |
1980年 | 175篇 |
1979年 | 174篇 |
1978年 | 150篇 |
1977年 | 137篇 |
1976年 | 129篇 |
1975年 | 119篇 |
1974年 | 129篇 |
1973年 | 111篇 |
1972年 | 93篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
971.
Werner J. Geldenhuys Robert Skolik Mary E. Konkle Michael A. Menze Timothy E. Long Aaron R. Robart 《Bioorganic & medicinal chemistry letters》2019,29(7):901-904
Nutrient-deprivation autophagy factor-1 (NAF-1, miner1; gene cisd2) is part of the [2Fe-2S]-containing protein family which includes mitoNEET (gene cisd1) and MiNT (miner2; gene cisd3). These proteins are redox active and are thought to play an important role in cellular energy homeostasis with NAF-1 playing a critical role in calcium regulation and aging. To date, no studies have investigated potential ligand interaction with NAF-1. Here we show that the thiazolidinediones pioglitazone and rosiglitazone along with the mitoNEET ligand, NL-1, bind to NAF-1 with low micromolar affinities. Further, we show that overexpression of NAF-1 in hepatocellular carcinoma (HepG2) cells reduces inhibition of mitochondrial respiration by pioglitazone. Our findings support the need for further efforts of the rational design of selective NAF-1 ligands. 相似文献
972.
973.
Swift Candice L. Brown Jennifer L. Seppälä Susanna O’Malley Michelle A. 《Journal of industrial microbiology & biotechnology》2019,46(9-10):1427-1433
Journal of Industrial Microbiology & Biotechnology - Anaerobic gut fungi are biomass degraders that form syntrophic associations with other microbes in their native rumen environment. Here,... 相似文献
974.
Winter Susanne Zaplata Markus Klemens Rzanny Michael Schaaf Wolfgang Fischer Anton Ulrich Werner 《Plant Ecology》2019,220(4-5):499-509
Plant Ecology - Ecological multifunctionality quantifies the functional performance of various important plant traits and increases with growing structural habitat heterogeneity, number of plant... 相似文献
975.
Soumitra Paul Chowdhury Doreen Babin Martin Sandmann Samuel Jacquiod Loreen Sommermann Søren Johannes Sørensen Andreas Fliessbach Paul Mäder Joerg Geistlinger Kornelia Smalla Michael Rothballer Rita Grosch 《Environmental microbiology》2019,21(7):2426-2439
Long-term agricultural fertilization strategies gradually change soil properties including the associated microbial communities. Cultivated crops recruit beneficial microbes from the surrounding soil environment via root exudates. In this study, we aimed to investigate the effects of long-term fertilization strategies across field sites on the rhizosphere prokaryotic (Bacteria and Archaea) community composition and plant performance. We conducted growth chamber experiments with lettuce (Lactuca sativa L.) cultivated in soils from two long-term field experiments, each of which compared organic versus mineral fertilization strategies. 16S rRNA gene amplicon sequencing revealed the assemblage of a rhizosphere core microbiota shared in all lettuce plants across soils, going beyond differences in community composition depending on field site and fertilization strategies. The enhanced expression of several plant genes with roles in oxidative and biotic stress signalling pathways in lettuce grown in soils with organic indicates an induced physiological status in plants. Lettuce plants grown in soils with different fertilization histories were visibly free of stress symptoms and achieved comparable biomass. This suggests a positive aboveground plant response to belowground plant–microbe interactions in the rhizosphere. Besides effects of fertilization strategy and field site, our results demonstrate the crucial role of the plant in driving rhizosphere microbiota assemblage. 相似文献
976.
Marta Tischer Michał Gorczak Błażej Bojarski Julia Pawłowska Christel Hoffeins Hans Werner Hoffeins Marta Wrzosek 《Fungal biology》2019,123(11):804-810
Three new fossils of saprotrophic fungi are presented and described from Baltic amber, dated to Eocene epoch (Paleogene, upper to mid-Eocene). All belong to Ascomycota and are represented by hyphae as well as asexual reproduction structures allowing to assign them to present genera, respectively Periconia, Penicillium and Scopulariopsis. These material provide both the first and the oldest known fossil record of the mentioned taxa, making these data valuable for the knowledge about the evolutionary history of the Ascomycota. 相似文献
977.
978.
979.
Markus Oberpaul Stephan Brinkmann Michael Marner Sanja Mihajlovic Benedikt Leis Maria A. Patras Christoph Hartwig Andreas Vilcinskas Peter E. Hammann Till F. Schäberle Marius Spohn Jens Glaeser 《Microbial biotechnology》2022,15(2):415-430
High-throughput platforms facilitating screening campaigns of environmental samples are needed to discover new products of natural origin counteracting the spreading of antimicrobial resistances constantly threatening human and agricultural health. We applied a combination of droplet microfluidics and fluorescence-activated cell sorting (FACS)-based technologies to access and assess a microbial environmental sample. The cultivation performance of our microfluidics workflow was evaluated in respect to the utilized cultivation media by Illumina amplicon sequencing of a pool of millions of droplets, respectively. This enabled the rational selection of a growth medium supporting the isolation of microbial diversity from soil (five phyla affiliated to 57 genera) including a member of the acidobacterial subgroup 1 (genus Edaphobacter). In a second phase, the entire diversity covered by 1071 cultures was used for an arrayed bioprospecting campaign, resulting in > 6000 extracts tested against human pathogens and agricultural pests. After redundancy curation by using a combinatorial chemical and genomic fingerprinting approach, we assigned the causative agents present in the extracts. Utilizing UHPLC-QTOF-MS/MS-guided fractionation and microplate-based screening assays in combination with molecular networking the production of bioactive ionophorous macrotetrolides, phospholipids, the cyclic lipopetides massetolides E, F, H and serratamolide A and many derivatives thereof was shown. 相似文献
980.
Seletzky JM Noak U Fricke J Welk E Eberhard W Knocke C Büchs J 《Biotechnology and bioengineering》2007,98(4):800-811
Scale-up from shake flasks to fermenters has been hampered by the lack of knowledge concerning the influence of operating conditions on mass transfer, hydromechanics, and power input. However, in recent years the properties of shake flasks have been described with empirical models. A practical scale-up strategy for everyday use is introduced for the scale-up of aerobic cultures from shake flasks to fermenters in batch and continuous mode. The strategy is based on empirical correlations of the volumetric mass transfer coefficient (k(L) a) and the pH. The accuracy of the empirical k(L) a correlations and the assumptions required to use these correlations for an arbitrary biological medium are discussed. To determine the optimal pH of the culture medium a simple laboratory method based on titration curves of the medium and a mechanistic pH model, which is solely based on the medium composition, is applied. The effectiveness of the scale-up strategy is demonstrated by comparing the behavior of Corynebacterium glutamicum on lactic acid in shake flasks and fermenters in batch and continuous mode. The maximum growth rate (micro(max) = 0.32 h(-1)) and the oxygen substrate coefficient (Y O2 /S= 0.0174 mol/l) of C. glutamicum on lactic acid were equal for shake flask, fermenter, batch, and continuous cultures. The biomass substrate yield was independent of the scale, but was lower in batch cultures (Y(X/S) = 0.36 g/g) than in continuous cultures (Y(X/S) = 0.45 g/g). The experimental data (biomass, respiration, pH) could be described with a simple biological model combined with a mechanistic pH model. 相似文献