全文获取类型
收费全文 | 955篇 |
免费 | 57篇 |
国内免费 | 1篇 |
出版年
2023年 | 4篇 |
2021年 | 6篇 |
2018年 | 11篇 |
2017年 | 4篇 |
2016年 | 15篇 |
2015年 | 27篇 |
2014年 | 24篇 |
2013年 | 33篇 |
2012年 | 34篇 |
2011年 | 50篇 |
2010年 | 33篇 |
2009年 | 24篇 |
2008年 | 44篇 |
2007年 | 47篇 |
2006年 | 32篇 |
2005年 | 47篇 |
2004年 | 43篇 |
2003年 | 52篇 |
2002年 | 48篇 |
2001年 | 46篇 |
2000年 | 30篇 |
1999年 | 21篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 30篇 |
1991年 | 25篇 |
1990年 | 30篇 |
1989年 | 26篇 |
1988年 | 18篇 |
1987年 | 15篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 15篇 |
1976年 | 6篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1969年 | 8篇 |
1965年 | 5篇 |
排序方式: 共有1013条查询结果,搜索用时 28 毫秒
1.
J Murata I Saiki I Azuma N Nishi 《International journal of biological macromolecules》1989,11(2):97-99
A new type of polypeptide containing the repeating sequence of cell attachment site in laminin, poly(Tyr-Ile-Gly-Ser-Arg), was synthesized by the polymerization procedure with diphenylphosphoryl azide (DPPA). We found that this polypeptide inhibited the metastatic formation in the lung of malignant tumour cells far more effectively than pentapeptide. 相似文献
2.
J Sun N Takahashi H Kakinuma Y Nishi 《Journal of immunology (Baltimore, Md. : 1950)》2001,167(10):5775-5785
Catalytic Abs (catAbs) preferentially evolved in autoimmune MRL/MPJ-lpr/lpr (MRL/lpr) mice upon immunization with the phosphonate transition-state analogue (TSA), but this did not happen in normal BALB/c mice. The majority of the catAbs from MRL/lpr mice were from several independent clones of the same family. Most of them had a lysine at position 95 in the heavy chain (H95), which is at the junctional region. This residue, which interacts with the phosphonate moiety of the TSA and presumably is involved in the catalytic activity, was not changed even after expansive evolution following multiple mutations. By contrast, the majority that arose from BALB/c mice were the non-catAbs, which were quite different in the sequence from the catAbs from MRL/lpr mice, but they were clonally related to one another, so most of them were originated from a single clone. In the MRL/lpr mice, the catalytic subsets that existed in the initial repertoire were effectively captured by the phosphonyl oxygens in the TSA by interacting with the lysine at H95. In the BALB/c mice, however, another noncatalytic subset with only the binding capability directed to a moiety other than the phosphonate moiety was alternatively evolved, because of the lowest abundance or elimination of the catalytic subsets. 相似文献
3.
4.
A respiration-deficient (RD) mutant was isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii. One strain among sixteen glycerol-non-utilizing mutants exhibited vigorous liberation of CO2 but no uptake of O2. Furthermore, this strain lacked cytochrome aa3 and had a reduced level of cytochrome b. The few mitochondria found in cells of this strain contained few or no cristae. Salt tolerance and intracellular accumulation of glycerol by the RD strain were almost equal to that of the wild-type strain in media containing NaCl up to 2.5 M. In media with more than 3 M NaCl, the growth of the RD mutant was retarded and the intracellular accumulation of glycerol was depressed in spite of ample production. 相似文献
5.
Soybean is the most important leguminous crop in Brazil and the nitrogen required for plant growth is supplied byBradyrhizobium bacteria through the symbiotic relation established by the inoculation process. Since 1992, two new strains, CPAC 7 and CPAC
15, which have been shown to increase yields in several field experiments, have been recommended in Brazilian commercial inoculants.
CPAC 15 is a natural variant of theB. elkanii SEMIA 566 strain, and was isolated after several years of adaptation to a Brazilian Cerrado soil, while CPAC 7 is a variant
ofB. japonicum strain CB 1809, selected under laboratory conditions for higher nodulation and yield. The comparison between parental and
variant strains, under greenhouse conditions, showed that both CPAC 15 and CPAC 7 increased N2 fixation rates in relation to the parental strains. The better performance of CPAC 15 was related to an increase in nodule
efficiency (mg N2 fixed mg-1 nodule) while with CPAC 7 the higher N2 fixation rates were due to increased nodulation. Both CPAC 15 and CPAC 7 increased nodule occupancy, when co-inoculated at
a ratio of 1:1 withB. elkanii 29w, in relation to their parental strains. Variant strains also differed from parental in their ability to increase numbers
of root hairs (Hai phenotype) either when inoculated onto plants, or when supernatants of bacteria exposed to seed exudates
were used as inoculants. This results lead to the hypothesis that a modification in some of the “common” nodulation genes
had occurred. However, the increase in Hai phenotype with CPAC 7 was dependent on the soybean cultivar, indicating a possible
alteration in some genotypic specific nodulation gene. Apparently, there were no differences in Nod metabolites produced by
strains CPAC 15 and SEMIA 566, but a more detailed chemical analysis would be required to rule out subtle differences. On
the contrary, significant differences were found between CPAC 7 and the parental strain CP 1809, in the profile of Nod metabolites.
Consequently, it may be possible that diffusable molecules, responsible for Hai phenotype, would be related to nodulation
ability, competiviveness, and N2 fixation, resulting in the higher yields that have been associated with CPAC 7 and CPAC 15. For the CPAC 7 strain, the increase
in Hai phenotype could be atributed to the differences found in the Nod molecules. Consequently, a high degree of physiological
and genetic variability can result from the adaptation of rhizobial strains to the soil. Also, this variability can be found
under laboratory conditions, when searching single colonies with specific properties. ei]Section editor: R O D Dixon 相似文献
6.
7.
8.
9.
Takashi Ohnuki Masahiko Ejiri Masaaki Kizuka Mie Fujiwara Takahide Nishi 《Bioorganic & medicinal chemistry letters》2019,29(2):199-203
We herein report a practical one-step glucuronidation method by biotransformation using Streptomyces sp. SANK 60895. This novel direct method of biotransformation has been shown to be more practical and scalable for glucuronidation than previously reported chemical and enzymatic procedures given its simplicity, high β-selectivity, cost-effectiveness, and reproducibility. We applied the present method to the synthesis of acyl glucuronide and hydroxy-β-glucuronide of mycophenolic acid and compound 4, respectively. This method was also shown to be applicable to the N-glucuronidation of various compounds. 相似文献
10.
Timothy D. Rohrbach Nishi Shah William P. Jackson Erin V. Feeney Samantha Scanlon Robert Gish Ryan Khodadadi Stephen O. Hyde Patricia H. Hicks Joshua C. Anderson John S. Jarboe Christopher D. Willey 《PloS one》2015,10(10)
Translocation to the nucleus of diacylglycerol kinase (DGK)– ζ is dependent on a sequence homologous to the effector domain of Myristoylated Alanine Rich C-Kinase Substrate (MARCKS). These data would suggest that MARCKS could also localize to the nucleus. A single report demonstrated immunofluorescence staining of MARCKS in the nucleus; however, further experimental evidence confirming the specific domain responsible for this localization has not been reported. Here, we report that MARCKS is present in the nucleus in GBM cell lines. We then over-expressed wild-type MARCKS (WT) and MARCKS with the effector domain deleted (ΔED), both tagged with V5-epitope in a GBM cell line with low endogenous MARCKS expression (U87). We found that MARCKS-WT localized to the nucleus, while the MARCKS construct without the effector domain remained in the cytoplasm. We also found that over-expression of MARCKS-WT resulted in a significant increase in total cellular phosphatidyl-inositol (4,5) bisphosphate (PIP2) levels, consistent with prior evidence that MARCKS can regulate PIP2 levels. We also found increased staining for PIP2 in the nucleus with MARCKS-WT over-expression compared to MARCKS ΔED by immunofluorescence. Interestingly, we observed MARCKS and PIP2 co-localization in the nucleus. Lastly, we found changes in gene expression when MARCKS was not present in the nucleus (MARCKS ΔED). These data indicate that the MARCKS effector domain can function as a nuclear localization signal and that this sequence is critical for the ability of MARCKS to regulate PIP2 levels, nuclear localization, and gene expression. These data suggests a novel role for MARCKS in regulating nuclear functions such as gene expression. 相似文献