全文获取类型
收费全文 | 5495篇 |
免费 | 803篇 |
国内免费 | 899篇 |
出版年
2024年 | 51篇 |
2023年 | 296篇 |
2022年 | 424篇 |
2021年 | 602篇 |
2020年 | 496篇 |
2019年 | 562篇 |
2018年 | 443篇 |
2017年 | 363篇 |
2016年 | 349篇 |
2015年 | 419篇 |
2014年 | 548篇 |
2013年 | 439篇 |
2012年 | 267篇 |
2011年 | 223篇 |
2010年 | 122篇 |
2009年 | 119篇 |
2008年 | 96篇 |
2007年 | 96篇 |
2006年 | 101篇 |
2005年 | 106篇 |
2004年 | 90篇 |
2003年 | 108篇 |
2002年 | 78篇 |
2001年 | 80篇 |
2000年 | 89篇 |
1999年 | 64篇 |
1998年 | 50篇 |
1997年 | 60篇 |
1996年 | 55篇 |
1995年 | 59篇 |
1994年 | 49篇 |
1993年 | 23篇 |
1992年 | 46篇 |
1991年 | 26篇 |
1990年 | 18篇 |
1989年 | 24篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1985年 | 23篇 |
1984年 | 30篇 |
1983年 | 17篇 |
1982年 | 22篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 1篇 |
排序方式: 共有7197条查询结果,搜索用时 664 毫秒
191.
Vincenzo Forgetta Gary Leveque Joana Dias Deborah Grove Robert Lyons Jr. Suzanne Genik Chris Wright Sushmita Singh Nichole Peterson Michael Zianni Jan Kieleczawa Robert Steen Anoja Perera Doug Bintzler Scottie Adams Will Hintz Volker Jacobi Louis Bernier Roger Levesque Ken Dewar 《Journal of biomolecular techniques》2013,24(1):39-49
As part of the DNA Sequencing Research Group of the Association of Biomolecular Resource Facilities, we have tested the reproducibility of the Roche/454 GS-FLX Titanium System at five core facilities. Experience with the Roche/454 system ranged from <10 to >340 sequencing runs performed. All participating sites were supplied with an aliquot of a common DNA preparation and were requested to conduct sequencing at a common loading condition. The evaluation of sequencing yield and accuracy metrics was assessed at a single site. The study was conducted using a laboratory strain of the Dutch elm disease fungus Ophiostoma novo-ulmi strain H327, an ascomycete, vegetatively haploid fungus with an estimated genome size of 30–50 Mb. We show that the Titanium System is reproducible, with some variation detected in loading conditions, sequencing yield, and homopolymer length accuracy. We demonstrate that reads shorter than the theoretical minimum length are of lower overall quality and not simply truncated reads. The O. novo-ulmi H327 genome assembly is 31.8 Mb and is comprised of eight chromosome-length linear scaffolds, a circular mitochondrial conti of 66.4 kb, and a putative 4.2-kb linear plasmid. We estimate that the nuclear genome encodes 8613 protein coding genes, and the mitochondrion encodes 15 genes and 26 tRNAs. 相似文献
192.
Julio C. González-Olvera Eva González-Jasso Alejandra Rojas-Molina 《Nucleosides, nucleotides & nucleic acids》2013,32(9):642-655
AbstractDegradation of 2′-deoxyribonucleosides in 0.5?M aqueous pyrrolidine at 110?°C proceeds at different rates, ordered as deoxyuridine?>?deoxyadenosine?>?deoxycytidine?>?deoxyguanosine ??deoxythymidine. Deoxyadenosine degradation produces the free base, adenine, while deoxycytidine by deamination produces deoxyuridine, and then uracil. The solvolysis of deoxyadenosine has an activation energy of 23.3?kcal/mol. Ammonolysis is slower than pyrrolidinolysis for deoxyadenosine, but faster for deoxyguanosine. In pyrrolidinolysis of the trinucleotides, d-TGT and d-TAT, the guanine moiety reacts faster than the adenine moiety. These trends are interpreted in terms of the ionization of the guanine moieties under basic conditions, rendering them less susceptible to nucleophilic attack. 相似文献
193.
Antonio Mu?oz-Mérida Juan José González-Plaza Andrés Ca?ada Ana María Blanco Maria del Carmen García-López José Manuel Rodríguez Laia Pedrola M. Dolores Sicardo M. Luisa Hernández Raúl De la Rosa Angjelina Belaj Mayte Gil-Borja Francisco Luque José Manuel Martínez-Rivas David G. Pisano Oswaldo Trelles Victoriano Valpuesta Carmen R. Beuzón 《DNA research》2013,20(1):93-108
Olive breeding programmes are focused on selecting for traits as short juvenile period, plant architecture suited for mechanical harvest, or oil characteristics, including fatty acid composition, phenolic, and volatile compounds to suit new markets. Understanding the molecular basis of these characteristics and improving the efficiency of such breeding programmes require the development of genomic information and tools. However, despite its economic relevance, genomic information on olive or closely related species is still scarce. We have applied Sanger and 454 pyrosequencing technologies to generate close to 2 million reads from 12 cDNA libraries obtained from the Picual, Arbequina, and Lechin de Sevilla cultivars and seedlings from a segregating progeny of a Picual × Arbequina cross. The libraries include fruit mesocarp and seeds at three relevant developmental stages, young stems and leaves, active juvenile and adult buds as well as dormant buds, and juvenile and adult roots. The reads were assembled by library or tissue and then assembled together into 81 020 unigenes with an average size of 496 bases. Here, we report their assembly and their functional annotation. 相似文献
194.
195.
196.
B. Lakshminarayanan C.M. Guinane P.M. O'Connor M. Coakley C. Hill C. Stanton P.W. O'Toole R.P. Ross 《Journal of applied microbiology》2013,114(3):886-898
Aims
To isolate and characterize bacteriocins produced by predominant species of lactic acid bacteria from faeces of elderly subjects.Methods and Results
Screening over 70 000 colonies, from faecal samples collected from 266 subjects, using the indicator organisms Lactobacillus bulgaricus LMG 6901 and Listeria innocua DPC 3572, identified 55 antimicrobial‐producing bacteria. Genomic fingerprinting following ApaI digestion revealed 15 distinct strains. The antimicrobial activities associated with 13 of the 15 strains were sensitive to protease treatment. The predominant antimicrobial‐producing species were identified as Lactobacillus salivarius, Lactobacillus gasseri, Lactobacillus acidophilus, Lactobacillus crispatus and Enterococcus spp. A number of previously characterized bacteriocins, including ABP‐118 and salivaricin B (from Lact. salivarius), enterocin B (Enterococcus faecium), lactacin B (Lact. acidophilus), gassericin T and a variant of gassericin A (Lact. gasseri), were identified. Interestingly, two antimicrobial‐producing species, not generally associated with intestinally derived microorganisms were also isolated: Lactococcus lactis producing nisin Z and Streptococcus mutans producing mutacin II.Conclusion
These data suggest that bacteriocin production by intestinal isolates against our chosen targets under the screening conditions used was not frequent (0·08%).Significance and Impact of the Study
The results presented are important due to growing evidence indicating bacteriocin production as a potential probiotic trait by virtue of strain dominance and/or pathogen inhibition in the mammalian intestine. 相似文献197.
Assessment of human adenovirus removal by qPCR in an advanced water reclamation plant in Georgia,USA
P. Liu O. Herzegh M. Fernandez S. Hooper W. Shu J. Sobolik R. Porter N. Spivey C. Moe 《Journal of applied microbiology》2013,115(1):310-318
Aims
To assess human adenoviruses (HAdVs) removal in an advanced wastewater treatment facility and compare two parallel tertiary treatment methods for the removal of HAdVs.Methods and Results
Tangential flow ultrafiltration was used to concentrate the water samples, and HAdVs were precipitated by polyethylene glycol. HAdVs were detected only by TaqMan real‐time PCR, and HAdV genotype was determined by DNA sequence. HAdVs were detected in 100% of primary clarification influent, secondary clarification effluent and granular media (GM) filtration effluent samples but only in 31·2% of membrane filtration (MF) effluent and 41·7% of final effluent (FE) samples, respectively. The average HAdVs loads were significantly reduced along the treatments but HAdVs were still present in FE. Comparison of two parallel treatments (GM vs MF) showed that MF was technically superior to GM for the removal of HAdVs.Conclusions
These findings indicate that adenoviruses are not completely removed by treatment processes. MF is a better treatment for removal of adenoviruses than GM filtration. Because only qPCR was used, the results only indicate the removal of adenovirus DNA and not the infectivity of viruses.Significance and Impact of the Study
Presence of HAdVs in FE by qPCR suggests a potential public health risk from exposure to the treated wastewater and using the FE for recreational or water reuse purposes should be cautious. 相似文献198.
Romain Philippe Etienne Paux Isabelle Bertin Pierre Sourdille Fréderic Choulet Christel Laugier Hana ?imková Jan ?afá? Arnaud Bellec Sonia Vautrin Zeev Frenkel Federica Cattonaro Federica Magni Simone Scalabrin Mihaela M Martis Klaus FX Mayer Abraham Korol Hélène Bergès Jaroslav Dole?el Catherine Feuillet 《Genome biology》2013,14(6):R64
Background
As for other major crops, achieving a complete wheat genome sequence is essential for the application of genomics to breeding new and improved varieties. To overcome the complexities of the large, highly repetitive and hexaploid wheat genome, the International Wheat Genome Sequencing Consortium established a chromosome-based strategy that was validated by the construction of the physical map of chromosome 3B. Here, we present improved strategies for the construction of highly integrated and ordered wheat physical maps, using chromosome 1BL as a template, and illustrate their potential for evolutionary studies and map-based cloning.Results
Using a combination of novel high throughput marker assays and an assembly program, we developed a high quality physical map representing 93% of wheat chromosome 1BL, anchored and ordered with 5,489 markers including 1,161 genes. Analysis of the gene space organization and evolution revealed that gene distribution and conservation along the chromosome results from the superimposition of the ancestral grass and recent wheat evolutionary patterns, leading to a peak of synteny in the central part of the chromosome arm and an increased density of non-collinear genes towards the telomere. With a density of about 11 markers per Mb, the 1BL physical map provides 916 markers, including 193 genes, for fine mapping the 40 QTLs mapped on this chromosome.Conclusions
Here, we demonstrate that high marker density physical maps can be developed in complex genomes such as wheat to accelerate map-based cloning, gain new insights into genome evolution, and provide a foundation for reference sequencing. 相似文献199.
200.
Maria C Romay Mark J Millard Jeffrey C Glaubitz Jason A Peiffer Kelly L Swarts Terry M Casstevens Robert J Elshire Charlotte B Acharya Sharon E Mitchell Sherry A Flint-Garcia Michael D McMullen James B Holland Edward S Buckler Candice A Gardner 《Genome biology》2013,14(6):R55