全文获取类型
收费全文 | 1957篇 |
免费 | 172篇 |
国内免费 | 2篇 |
出版年
2022年 | 17篇 |
2021年 | 25篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 26篇 |
2017年 | 27篇 |
2016年 | 45篇 |
2015年 | 80篇 |
2014年 | 90篇 |
2013年 | 99篇 |
2012年 | 156篇 |
2011年 | 126篇 |
2010年 | 89篇 |
2009年 | 82篇 |
2008年 | 137篇 |
2007年 | 119篇 |
2006年 | 122篇 |
2005年 | 121篇 |
2004年 | 106篇 |
2003年 | 96篇 |
2002年 | 86篇 |
2001年 | 45篇 |
2000年 | 20篇 |
1999年 | 33篇 |
1998年 | 33篇 |
1997年 | 26篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 26篇 |
1993年 | 20篇 |
1992年 | 25篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 14篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1974年 | 6篇 |
1973年 | 7篇 |
1972年 | 7篇 |
1968年 | 5篇 |
排序方式: 共有2131条查询结果,搜索用时 15 毫秒
21.
PET1402, a nuclear gene required for proteolytic processing of cytochrome oxidase subunit 2 in yeast
Mathias Bauer Meinhardt Behrens Karlheinz Esser Georg Michaelis Elke Pratje 《Molecular & general genetics : MGG》1994,245(3):272-278
The nuclear mutation pet ts1402 prevents proteolytic processing of the precursor of cytochrome oxidase subunit 2 (cox2) in Saccharomyces cerevisiae. The structural gene PET1402 was isolated by genetic complementation of the temperature-sensitive mutation. DNA sequence analysis identified a 1206-bp open reading frame, which is located 215 by upstream of the PET122 gene. The DNA sequence of PET1402 predicts a hydrophobic, integral membrane protein with four transmembrane segments and a typical mitochondrial targeting sequence. Weak sequence similarity was found to two bacterial proteins of unknown function. Haploid cells containing a null allelle of PET1402 are respiratory deficient. 相似文献
22.
Sequence analysis of cohesive ends of the actinophage RP3 genome and construction of a transducible shuttle vector 总被引:2,自引:0,他引:2
Abstract The sequence of the cohesive ends of actinophage RP3 DNA has been determined. As with all other phages of Gram-positive bacteria that have been studied sofar, RP3 DNA has 3'-protruding ends. A shuttle cosmid has been constructed containing this cos area which can be efficiently transduced by phage RP3 to host cells of Streptomyces rimosus . 相似文献
23.
Improved growth and methane production conditions for Methanobacterium thermoautotrophicum 总被引:1,自引:0,他引:1
Elke Gerhard Bertram M. Butsch Ian W. Marison Urs von Stockar 《Applied microbiology and biotechnology》1993,40(2-3):432-437
Methanobacterium thermoautotrophicum was grown on a defined mineral salts medium under strictly anaerobic conditions with H2 and CO2 as the sole energy and carbon sources, respectively. The cultivation medium was optimized with respect to non-organic components including Se(IV), W(VI), N, Ni(II), Fe(II), Co(II) and Mo(VI). Sulphide concentration in the medium was maintained constant using an on-line regulatory system by the addition of 0.5 M Na2S. A maximum supply rate of 0.6 vvm of a mixture of 80% H2 and 20% CO2 was achieved for the gaseous substrates. Under these conditions a specific growth rate of 0.30 h–1 and a cell concentration of 4.8 g cell dry weight (DW) l–1, representing a 140% increase over previously published results, were obtained. The growth yield of 2.3 g DW mol–1 CH4 was similar to published values. However, the overall specific productivity was enhanced from 11 mmol CH4 g–1 DW h–1 to 24 mmol CH4 g–1 DW h–1, corresponding to an improvement of 120%.
Correspondence to: U. von Stockar 相似文献
24.
Glutamate Dehydrogenase Is Not Essential for Glutamate Formation by Corynebacterium glutamicum
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Elke R. Brmann-El Kholy Bernhard J. Eikmanns Marcella Gutmann Hermann Sahm 《Applied microbiology》1993,59(7):2329-2331
Two Corynebacterium glutamicum strains, one being glutamate dehydrogenase (GDH) negative and the other possessing 11-fold-higher specific GDH activity than the parental wild type, were constructed and used to analyze the role of GDH in C. glutamicum. The results indicate (i) that GDH is dispensable for glutamate synthesis required for growth and (ii) that although a high level of GDH increases the intracellular glutamate pool, the level of GDH has no influence on glutamate secretion. 相似文献
25.
Andreas Klöti Victor A. Iglesias Joachim Wünn Peter K. Burkhardt Swapan K. Datta Ingo Potrykus 《Plant cell reports》1993,12(12):671-675
Summary Gene transfer into intact cells was achieved by electroporating zygotic wheat embryos without any special pretreatment. Electroporation was tissue specific in so far as scutellum cells were found to be much more susceptible to gene transfer than other cell types of the embryo. The orientation of the embryos in the electroporation chamber also influenced the number of transformed scutellum cells; during electroporation, as in electrophoresis, the negatively charged plasmid DNA molecules seemed to move towards the positive electrode. Therefore, the embryos were arranged so that the scutella faced the negative electrode. The use of plasmids carrying either two chimeric anthocyanin regulatory genes or a chimeric gusA gene allowed clear identification of transformed cells in the scutellum. On some of the embryos, more than 100 transformed scutellum cells were found after electroporation with single electric pulses of 275 V/cm discharged from a 960-F capacitor and with 100 g DNA/ml electroporation buffer. Using the anthocyanin marker system, visibly transformed cells grew to produce red sectors.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- GUS
-glucuronidase
- MES
2-N-morpholinoethane sulfonic acid 相似文献
26.
Burkhardt JK 《Trends in cell biology》1996,6(4):127-131
The past few years have seen an explosion in the number of molecular motors reported in the literature. By us the energy of hydrolysis, these motors move various organelles along cytoskeletal 'tracks' within the cell. It is thought that some of the specificity of movement resides in receptors on the surface of the cargo organelles, but, in general, little is known about these molecules. In this article, Janis Burkhardt discusses the evidence that the protein kinectin serves as a membrane receptor for kinesin, and describes how motor-receptor proteins may interact with other components of the motility machinery to generate regulated movement of membrane organelles. 相似文献
27.
Johannes Becker-Follmann Andreas Gaa Elke Baùsch Ernst Natt Gerd Scherer Otto von Deimling 《Mammalian genome》1997,8(3):172-177
We have performed a high-resolution linkage analysis for the conserved segment on distal mouse Chromosome (Chr) 8 that is
homologous to human Chr 16q. The interspecific backcross used involved M. m. molossinus and an M. m. domesticus line congenic for an M. spretus segment from Chr 8 flanked by phenotypic markers Os (oligosyndactyly) and e, a coat colormarker. From a total of 682 N2 progeny, the 191 animals revealing a recombination event between these phenotypic markers were typed for 23 internal loci.
The following locus order with distances in cM was obtained: (centromere)–Os–4.1–Mmp2–0.2–Ces1,Es1, Es22–1.2–Mt1,D8Mit15–2.2–Got2, D8Mit11–3.7–Es30–0.3–Es2, Es7–0.9–Ctra1,Lcat–0.3–Cdh1, Cadp, Nmor1, D8Mit12–0.2–Mov34–2.5–Hp,Tat–0.2–Zfp4–1.6–Zfp1,Ctrb–10.9–e. In a separate interspecific cross involving 62 meioses, Dpep1 was mapped together with Aprt and Cdh3 at 12.9 cM distal to Hp, Tat, to the vicinity of e. Our data give locus order for markers not previously resolved, add Mmp2 and Dpep1 as new markers on mouse Chr 8, and indicate that Ctra1 is the mouse homolog for human CTRL. Comparison of the order of 17 mouse loci with that of their human homologs reveals that
locus order is well conserved and that the conserved segment in the human apparently spans the whole long arm of Chr 16.
Received: 30 July 1996 / Accepted: 15 November 1996 相似文献
28.
Enhanced quantitative resistance against fungal disease by combinatorial expression of different barley antifungal proteins in transgenic tobacco 总被引:26,自引:1,他引:25
Guido Jach Birgit Görnhardt John Mundy Jürgen Logemann Elke Pinsdorf Robert Leah Jeff Schell Christoph Maas 《The Plant journal : for cell and molecular biology》1995,8(1):97-109
cDNAs encoding three proteins from barley ( Hordeum vulgare ), a class-II chitinase (CHI), a class-II β-1,3-glucanase (GLU) and a Type-I ribosome-inactivating protein (RIP) were expressed in tobacco plants under the control of the CaMV 35S-promoter. High-level expression of the transferred genes was detected in the transgenic plants by Northern and Western blot analysis. The leader peptides in CHI and GLU led to accumulation of these proteins in the intercellular space of tobacco leaves. RIP, which is naturally deposited in the cytosol of barley endosperm cells, was expressed either in its original cytosolic form or fused to a plant secretion peptide (spRIP). Fungal infection assays revealed that expression of the individual genes in each case resulted in an increased protection against the soilborne fungal pathogen Rhizoctonia solani , which infects a range of plant species including tobacco. To create a situation similar to 'multi-gene' tolerance, which traditional breeding experience has shown to provide crops with a longer-lasting protection, several of these antifungal genes were combined and protection against fungal attack resulting from their co-expression in planta was evaluated. Transgenic tobacco lines were generated with tandemly arranged genes coding for RIP and CHI as well as GLU and CHI. The performance of tobacco plants co-expressing the barley transgenes GLU/ CHI or CHI/RIP in a Rhizoctonia solani infection assay revealed significantly enhanced protection against fungal attack when compared with the protection levels obtained with corresponding isogenic lines expressing a single barley transgene to a similar level. The data indicate synergistic protective interaction of the co-expressed anti-fungal proteins in vivo . 相似文献
29.
Jürgen Kunze Ulrich H. Frenzel Elke Hüttig Frank-Reiner Grosse Hans-Rudolf Wiedemann 《Human genetics》1977,35(2):237-240
Summary We report a newborn with incontinentia pigmenti Bloch-Sulzberger and male phenotype. Chromosome analysis revealed a Klinefelter's syndrome 47,XXY. These findings are compatible with the hypothesis of dominant sexlinked genes carried on the X-chromosome in this disease.
Zusammenfassung Wir berichten über ein neugeborenes Kind mit männlichem Phänotyp bei Incontinentia pigmenti Bloch-Sulzberger. Bei der klinischen Abklärung fand sich die Gonosomenaberration eines Klinefelter-Syndroms 47,XXY. Dieser Befund geht konform mit der Vermutung eines dominant X-gekoppelten Erbganges dieser seltenen Hauterkrankung.相似文献
30.
Kenneth N. Timmis Felipe Cabello Isabel Andrés Alfred Nordheim Hans J. Burkhardt Stanley N. Cohen 《Molecular & general genetics : MGG》1978,167(1):11-19
Summary Detailed examination of the structure of cloned DNA fragments of the R6-5 antibiotic resistance plasmid has revealed a substantial degree of polynucleotide sequence heterogeneity and indicates that sequence rearrangements in plasmids and possibly other replicons occur more frequently than has hitherto been appreciated. The sequence changes in cloned R6-5 fragments were shown in some instances to have occurred prior to cloning, i.e. existed in the original population of R6-5 molecules that was obtained from a single bacterial clone and by several different criteria judged to be homogeneous,and in others to have occurred either during the cloning procedure or during subsequent propagation of hybrid molecules. The molecular changes that are described involved insertion/deletion of the previously characterized IS2 insertion element, formation of a new inverted repeat structure probably by duplication of a preexisting R6-5 DNA sequence, sequence inversion, and loss and gain of restriction endonuclease cleavage sites. 相似文献