全文获取类型
收费全文 | 462篇 |
免费 | 36篇 |
专业分类
498篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 17篇 |
2014年 | 12篇 |
2013年 | 12篇 |
2012年 | 19篇 |
2011年 | 32篇 |
2010年 | 21篇 |
2009年 | 21篇 |
2008年 | 22篇 |
2007年 | 21篇 |
2006年 | 29篇 |
2005年 | 17篇 |
2004年 | 26篇 |
2003年 | 33篇 |
2002年 | 21篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 10篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1971年 | 3篇 |
1967年 | 2篇 |
1964年 | 3篇 |
排序方式: 共有498条查询结果,搜索用时 15 毫秒
71.
72.
Bent Larsen 《Animal genetics》1982,13(2):115-121
The F system of three Danish cattle breeds as determined by four specific anti-sera is described. In the Jersey breed three alleles are recognised. In the Danish cattle breeds there was no indication of a null allele. However, the phenotypes observed in zebu cattle by means of four reagents suggest the presence of at least six alleles in the bovine F system. Furthermore, the data show that the factors V1 and V2 do not form a linear subtype system in all cattle breeds. 相似文献
73.
Twenty-three strains of Sphaerophorus necrophorus, isolated from animal pathological processes, were characterized. The two biotypes of Fievez (1963) were recognized, differing in colony morphology, cell morphology, degree of hemolysis, growth modus in broth, and hemagglutination. The following characters were shared by all strains: Gram-negative, anaerobic, nonsporeforming, immotile rods, producing acid from fructose, glucose, mannose, maltose, and (variably) from galactose, but not from arabinose, xylose, lactose, saccharose, cellobiose, melezitose, adonitole, sorbitole, mannitole, and salicine. Terminal pH in glucose medium was 5.77 ± 0.17. Growth was not inhibited by 0.008 % brilliant green, but was partially inhibited by 10 % ox bile. Indole was produced. Nitrate was not reduced. A lecitinase was present. Proteolytic properties were present. Threonine was deaminated. The fatty acids: acetic, propionic, and butyric acid were produced in medium both with and without glucose. 相似文献
74.
Lars Hagerman Bent Vismann 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2001,171(8):695-699
Dialysed haemocyanin from the isopod Saduria entomon had a considerably increased oxygen affinity (lower P50) and Bohr factor (-1.71) compared to native haemocyanin (Bohr factor -1.36) indicating that dialysis removes a small molecule size modulating factor decreasing the affinity of native haemolymph. Dialysed haemocyanin had a slightly lower co-operativity (2.42 +/- 0.3) than native haemocyanin (2.9 +/- 0.2). L-Lactate (10 mmol l(-1)) improved oxygen affinity by 1-1.5 torr while urate had no effect. Mg2+ affected affinity in a pH-dependent manner (Bohr-factor increased to -1.67) while Ca2+ had no effect on the Bohr factor but increased affinity with ca 1 torr. Thiosulphate changed the Bohr factor to -1.75 to -1.82, similar to dialysed blood. Co-operativity was in neither case affected. The haemocyanin characteristics of S. entomon are similar to those of crustaceans from hydrothermal vents. These characteristics are probably general for crustaceans that are more or less permanently exposed to sulphide. 相似文献
75.
K J Bent 《Journal of general microbiology》1967,49(2):195-200
76.
77.
78.
Alterations in plant growth and in root hormone levels of lodgepole pines inoculated with rhizobacteria. 总被引:1,自引:0,他引:1
The presence of other soil microorganisms might influence the ability of rhizobacterial inoculants to promote plant growth either by reducing contact between the inoculant and the plant root or by interfering with the mechanism(s) involved in rhizobacterially mediated growth promotion. We conducted the following experiments to determine whether reductions in the extent of growth promotion of lodgepole pine mediated by Paenibacillus polymyxa occur in the presence of a forest soil isolate (Pseudomonas fluorescens M20) and whether changes in plant growth promotion mediated by P. polymyxa (i) are related to changes in P. polymyxa density in the rhizosphere or (ii) result from alterations in root hormone levels. The extent of plant growth, P. polymyxa rhizosphere density, and root hormone concentrations were determined for lodgepole pine treated with (i) a single growth-promoting rhizobacterial strain (P. polymyxa L6 or Pw-2) or (ii) a combination of bacteria: strain L6 + strain M20 or strain Pw-2 + strain M20. There was no difference in the growth of pines inoculated with strain L6 and those inoculated with strain L6 + strain M20. However, seedlings inoculated with strain Pw-2 had more lateral roots and greater root mass at 12 weeks after inoculation than plants inoculated with strain Pw-2 + strain M20. The extent of growth promotion mediated by P. polymyxa L6 and Pw-2 in each treatment was not correlated to the average population density of each strain in the rhizosphere. Bacterial species-specific effects were observed in root hormone levels: indole-3-acetic acid concentration was elevated in roots inoculated with P. polymyxa L6 or Pw-2, while dihydrozeatin riboside concentration was elevated in roots inoculated with P. fluorescens M20. 相似文献
79.
Palanichelvam K Oger P Clough SJ Cha C Bent AF Farrand SK 《Molecular plant-microbe interactions : MPMI》2000,13(10):1081-1091
Agrobacterium tumefaciens Chry5, which is particularly virulent on soybeans, induces tumors that produce a family of Amadori-type opines that includes deoxyfructosyl glutamine (Dfg) and its lactone, chrysopine (Chy). Cosmid clones mapping to the right of the known oncogenic T-region of pTiChry5 conferred Amadori opine production on tumors induced by the nopaline strain C58. Sequence analysis of DNA held in common among these cosmids identified two 25-bp, direct repeats flanking an 8.5-kb segment of pTiChry5. These probable border sequences are closely related to those of other known T-regions and define a second T-region of pTiChry5, called T-right (TR), that confers production of the Amadoriopines. The oncogenic T-left region (TL) was located precisely by identifying and sequencing the likely border repeats defining this segment. The two T-regions are separated by approximately 15 kb of plasmid DNA. Based on these results, we predicted that pKYRT1, a vir helper plasmid derived from pTiChry5, still contains all of TR and the leftmost 9 kb of TL. Consistent with this hypothesis, transgenic Arabidopsis thaliana plants selected for with a marker encoded by a binary plasmid following transformation with KYRT1 co-inherited production of the Amadori opines at high frequency. All opine-positive transgenic plants also contained TR-DNA, while those plants that lacked TR-DNA failed to produce the opines. Moreover, A. thaliana infected with KYRT1 in which an nptII gene driven by the 35S promoter of Cauliflower mosaic virus was inserted directly into the vir helper plasmid yielded kanamycin-resistant transformants at a low but detectable frequency. These results demonstrate that pKYRT1 is not disarmed, and can transfer Ti plasmid DNA to plants. A new vir helper plasmid was constructed from pTiChry5 by two rounds of sacB-mediated selection for deletion events. This plasmid, called pKPSF2, lacks both of the known T-regions and their borders. pKPSF2 failed to transfer Ti plasmid DNA to plants, but mobilized the T-region of a binary plasmid at an efficiency indistinguishable from those of pKYRT1 and the nopaline-type vir helper plasmid pMP90. 相似文献
80.
The intention of this review is to provide an overview of current methodologies employed in the rapidly developing field of ocular proteomics with emphasis on sample preparation, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Appropriate sample preparation for the diverse range of cells and tissues of the eye is essential to ensure reliable results. Current methods of protein staining for 2D-PAGE, protein labelling for two-dimensional difference gel electrophoresis, gel-based expression analysis and protein identification by MS are summarised. The uses of gel-free MS-based strategies (MuDPIT, iTRAQ, ICAT and SILAC) are also discussed. Proteomic technologies promise to shed new light onto ocular disease processes that could lead to the discovery of strong novel biomarkers and therapeutic targets useful in many ophthalmic conditions. 相似文献