全文获取类型
收费全文 | 702篇 |
免费 | 44篇 |
国内免费 | 1篇 |
专业分类
747篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 14篇 |
2015年 | 26篇 |
2014年 | 28篇 |
2013年 | 30篇 |
2012年 | 34篇 |
2011年 | 29篇 |
2010年 | 21篇 |
2009年 | 31篇 |
2008年 | 51篇 |
2007年 | 36篇 |
2006年 | 57篇 |
2005年 | 26篇 |
2004年 | 56篇 |
2003年 | 44篇 |
2002年 | 41篇 |
2001年 | 23篇 |
2000年 | 23篇 |
1999年 | 16篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1971年 | 4篇 |
1966年 | 2篇 |
排序方式: 共有747条查询结果,搜索用时 15 毫秒
71.
Lactic acid bacteria isolated from soy sauce mash in Thailand 总被引:5,自引:0,他引:5
Tanasupawat S Thongsanit J Okada S Komagata K 《The Journal of General and Applied Microbiology》2002,48(4):201-209
Fourteen sphere-shaped and 30 rod-shaped lactic acid bacteria were isolated from soy sauce mash of two factories in Thailand. These strains were separated into two groups, Group A and Group B, by cell shape and DNA-DNA similarity. Group A contained 14 tetrad-forming strains, and these strains were identified as Tetragenococcus halophilus by DNA similarity. Group B contained 30 rod-shaped bacteria, and they were further divided into four Subgroups, B1, B2, B3, and B4, and three ungrouped strains by phenotypic characteristics and DNA similarity. Subgroup B1 contained 16 strains, and these strains were identified as Lactobacillus acidipiscis by DNA similarity. Subgroup B2 included two strains, and the strains were identified as Lactobacillus farciminis by DNA similarity. Subgroup B3 contained five strains. The strains had meso-diaminopimelic acid in the cell wall, and were identified as Lactobacillus pentosus by DNA similarity. The strains tested produced DL-lactic acid from D-glucose. Subgroup B4 contained four strains. The strains had meso-diaminopimelic acid in the cell wall, and they were identified as Lactobacillus plantarum by DNA similarity. Two ungrouped strains were homofermentative, and one was heterofermentative. They showed a low degree of DNA similarity with the type strains tested, and were left unnamed. The distribution of lactic acid bacteria in soy sauce mash in Thailand is discussed. 相似文献
72.
Blue light was found to induce shrinkage of the protoplasts isolated from first-leaf lamina pulvini of 18-day-old Phaseolus vulgaris. The response was transient following pulse stimulation, while it was sustainable during continuous stimulation. No apparent difference was found between flexor and extensor protoplasts. Protoplasts of the petiolar segment located close to the pulvinus showed no detectable response. In the plants used, the pulvinus was fully matured and the petiole was ceasing its elongation growth. When younger, 12-day-old, plants were used, however, the petiolar protoplasts did respond to blue light. The pulse-induced response was similar to that in pulvinar protoplasts, although the response to continuous stimulation was transient and differed from that in pulvinar protoplasts. No shrinkage was induced in pulvinar protoplasts when the far-red-light-absorbing form of phytochrome was absent for a period before blue-light stimulation, indicating that the blue-light responsiveness is strictly controlled by phytochrome. Inhibitors of anion channels and H(+)-ATPase abolished the shrinking response, supporting the view that protoplasts shrink by extruding ions. The response of pulvinar protoplasts is probably involved in the blue-light-induced, turgor-based movement of pulvini. The blue-light responding system in pulvini is suggested to have evolved from that functioning in other growing organs. 相似文献
73.
We investigated the expression of an acquired host resistance against Staphylococcus aureus infection in mice. When C57BL/6 mice were immunized with viable S. aureus and challenged with S. aureus eight weeks later, the elimination of S. aureus from the spleen and liver was enhanced in the immunized mice compared with the nonimmunized mice. When gamma interferon (IFN-gamma(-/-)) mice were immunized and challenged, the bacterial numbers in the organs of immunized mice were comparable to those in the nonimmunized mice, suggesting that IFN-gamma plays a critical role in an acquired host resistance against S. aureus infection. IFN-gamma(-/-) mice produced the lower level of anti-S. aureus immunoglobulin M (IgM) and IgG2a antibodies compared with C57BL/6 mice. To elucidate the role of IFN-gamma produced during a challenge with S. aureus, a single injection of anti-IFN-gamma monoclonal antibody to mice was carried out 1 h before challenge. An acquired resistance against S. aureus infection was inhibited by injecting with anti-IFN-gamma monoclonal antibody. However, anti-IFN-gamma monoclonal antibody treatment failed to modulate anti-S. aureus IgM, IgG1 or IgG2a responses in these animals. These results demonstrated that IFN-gamma is required for an acquired resistance against S. aureus infection in mice. However, IFN-gamma induced during the challenge failed to affect the secondary antibody responses. 相似文献
74.
Sarashina I Yamaguchi H Haga T Iijima M Chiba S Endo K 《Journal of molecular evolution》2006,62(3):307-318
A major shell matrix protein originally obtained from a freshwater snail is a molluscan homologue of Dermatopontins, a group
of Metazoan proteins also called TRAMP (tyrosine-rich acidic matrix protein). We sequenced and identified 14 molluscan homologues
of Dermatopontin from eight snail species belonging to the order Basommatophora and Stylommatophora. The bassommatophoran
Dermatopontins fell into three types, one is suggested to be a shell matrix protein and the others are proteins having more
general functions based on gene expression analyses. N-glycosylation is inferred to be important for the function involved
in shell calcification, because potential N-glycosylation sites were found exclusively in the Dermatopontins considered as
shell matrix proteins. The stylommatophoran Dermatopontins fell into two types, also suggested to comprise a shell matrix
protein and a protein having a more general function. Phylogenetic analyses using maximum likelihood and Bayesian methods
revealed that gene duplication events occurred independently in both basommatophoran and stylommatophoran lineages. These
results suggest that the dermatopontin genes were co-opted for molluscan calcification at least twice independently after the divergence of basommatophoran and
stylommatophoran lineages, or more recently than we have expected.
[Reviewing Editor: Dr. David Pollock] 相似文献
75.
Taniguchi A Tsuchida S Kuno S Mita M Machida T Ioritani N Terai C Yamanaka H Kamatani N 《Nucleosides, nucleotides & nucleic acids》2004,23(8-9):1141-1145
Five mutations in the adenine phosphoribosyltransferase (APRT) gene have been described in Japanese patients with APRT deficiency. We investigated the APRT gene from three patients with APRT deficiency and two novel mutations, G133D and V84M, were determined. 相似文献
76.
G protein-coupled receptors (GPCRs) constitute one of the largest families of genes in the human genome, and are the largest targets for drug development. Although a large number of GPCR genes have recently been identified, ligands have not yet been identified for many of them. Various assay systems have been employed to identify ligands for orphan GPCRs, but there is still no simple and general method to screen for ligands of such GPCRs, particularly of G(i)-coupled receptors. We have examined whether fusion proteins of GPCRs with G protein alpha subunit (Galpha) could be utilized for ligand screening and showed that the fusion proteins provide an effective method for the purpose. This article focuses on the followings: (1) characterization of GPCR genes and GPCRs, (2) identification of ligands for orphan GPCRs, (3) characterization of GPCR-Galpha fusion proteins, and (4) identification of ligands for orphan GPCRs using GPCR-Galpha fusion proteins. 相似文献
77.
The complete nucleotide sequence of the phosphoprotein (P) gene of the Yamagata-1 strain of a defective subacute sclerosing panencephalitis (SSPE) virus was determined. Comparison with the P gene of the Edmonston strain of measles virus (MV) revealed 44 differences of which 23 nucleotides substitutions were identical with those revealed between other SSPE viruses and MV (Cattaneo et al. (1989) Virology 173, 415-425). The consensus sequence of the G insertion site was completely conserved, whereas mRNAs with one or three non-templated G residue insertions were found in addition to the mRNA of the exact genome copy. As a result of the frameshift downstream of the site of G insertion, the cysteine-rich V protein was predicted from the one G-inserted mRNA besides the P and C proteins predicted from the genome-copied mRNA. 相似文献
78.
Staphylococcus aureus lipase (SAL) is known to possess broad substrate specificity for triacylglycerides. We found that a sub-minimum inhibitory concentration of farnesol (1000 mg L(-1)) inhibits this lipase activity on a Mueller-Hinton agar containing 1% Tween substrates. A quantitative lipase assay using p-nitrophenyl palmitate (pNPP) revealed that the inhibitory action of farnesol appears to be the result of the inhibition of lipase activity rather than of its secretion into the culture medium. The inhibition was observed in all the tested 8 methicillin-susceptible S. aureus and 31 methicillin-resistant S. aureus clinical isolates. Using homogeneous lipase purified by hydrophobic interaction chromatography, it was revealed that farnesol could competitively inhibit the lipase activity against the substrate pNPP. 相似文献
79.
Changes in the population structure of Salpa thompsoni from austral mid-summer to autumn off the Adelie Coast, Antarctica, were examined using cluster analysis based on reproductive
states. S. thompsoni was the dominant macrozooplankton species through the research periods although the abundance decreased markedly in autumn.
In both summer and autumn we identified three geographically coherent subpopulations, which were considered to be either a
mating swarm or physical aggregation. Many aggregate forms with an empty (dead) embryo were observed, and the ratio of newborn
solitary forms decreased in autumn, indicating sexual reproduction of the salps was deactivated. The significant reduction
in size of mature solitaries suggested that the capacity of asexual reproduction was also reduced in autumn. In addition to
water temperature decline, the phytoplankton shortage (which was partly caused by high grazing pressure of S. thompsoni during summer) might be the factor causing decline in their own population size in autumn.
Accepted: 25 May 1999 相似文献
80.