全文获取类型
收费全文 | 238篇 |
免费 | 12篇 |
专业分类
250篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 6篇 |
2013年 | 22篇 |
2012年 | 14篇 |
2011年 | 17篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 14篇 |
2007年 | 19篇 |
2006年 | 19篇 |
2005年 | 15篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有250条查询结果,搜索用时 0 毫秒
101.
A general procedure for the cross-linking of enzyme to DNA has been developed for use as a nonradioactive probe. In this method, DNA is transaminated with diaminopropane to introduce primary amino groups into the cytosine residues. Then the amino groups are converted to thiol groups using a heterobifunctional cross-linker. The thiolated DNA is conjugated with the maleimide-introduced enzyme. With this method, alkaline phosphatase was cross-linked to a single-stranded DNA (sspUCRf1). The conjugate was able to detect 5 pg of target DNA (pUCf1 plasmid, 3.2 kbp) fixed onto the nitrocellulose membrane, using a colorimetric assay. The enzyme-conjugated DNA was applied to "the universal probe system," which consisted of two single-stranded DNA probes (a primary probe and a labeled secondary probe). Using alkaline phosphatase-conjugated sspUCRf1 DNA as the secondary probe, the c-myc gene and HBV DNA were detected effectively on Southern and dot-blot hybridization. 相似文献
102.
We determined the homogeneous nucleation temperature depression, ΔTf,hom, the equilibrium melting point depression, ΔTm, and the value λ, which can be obtained from the linear relationship ΔTf,hom = λΔTm, for aqueous solutions of PEG (200-20,000 g mol−1), PVP (10,000, 35,000, 40,000 g mol−1), and dextran (10,000 g mol−1) in the concentration range 0-40 wt% using the emulsion method. The molecular weight dependence of Tf,hom, Tm, and λ in PEG aqueous solutions was found to change in the vicinity of Mw 600-1540 at all concentrations. In addition, it was confirmed that for all of the polymers studied, there was a good linear relationship between λ and the logarithmic value of the self-diffusion coefficient D0 of the solute molecule. These results indicate that the parameters that describe non-equilibrium freezing, such as Tf,hom and λ, are dependent on solution properties such as viscosity and self-diffusion of solute molecules. 相似文献
103.
Shintani N Suetake S Hashimoto H Koga K Kasai A Kawaguchi C Morita Y Hirose M Sakai Y Tomimoto S Matsuda T Baba A 《Regulatory peptides》2005,126(1-2):123-128
104.
Fujii H Itoh Y Yamaguchi K Yamauchi N Harano Y Nakajima T Minami M Okanoue T 《Biochemical and biophysical research communications》2004,322(3):1052-1058
CCR6 is the receptor of chemokine CCL20. In the present study, we demonstrated that the surface expression of CCR6 was enhanced on the human HCC cell lines (HuH7, PLC/PRF/5, and HepG2) especially on HuH7 cells, but not on HLE or HLF cells. These HCC cell lines (HuH7, PLC/PRF/5, and HepG2) especially the HuH7 cells secreted a significant amount of CCL20 spontaneously, whereas HLE or HLF did not. Stimulation by CCL20 up-regulated the mRNA expression of CCR6 in HuH7 cells and significantly enhanced the growth of HuH7 cells. CCL20-stimulated growth of HuH7 cells was abrogated by the inhibition of downstream signal transduction pathway mediated by p44/42 MAPK, but not by p38 MAPK or SAPK/JNK. CCR6 expression in human HCC tissues was confirmed by RT-PCR. These results indicate that the growth of a proportion of human HCC cells may be mediated by CCL20-CCR6 axis, like HuH7 cells, in an autocrine or paracrine manner. 相似文献
105.
Shintani N Hashimoto H Tanaka K Kawaguchi C Tomimoto S Baba A 《Regulatory peptides》2004,123(1-3):155-159
PACAP exerts multiple activities as a hormone and neurotransmitter, and has been proposed to play vital roles in a variety of neuronal functions. PACAP is also involved in insulin secretion from pancreatic beta-cells. Recently, we and other groups demonstrated that PACAP-deficient mice (PACAP(-/-)) are viable, but suffer from increased postnatal mortality. To ascertain whether this high mortality is rescued by overexpression of PACAP in peripheral tissue (such as pancreas), we performed a genetic cross between PACAP(-/-) and our recently developed transgenic mice overexpressing PACAP in pancreatic beta-cells; and then examined the survival rate of their F2 progeny. PACAP(-/-) mice were segregated into two groups based on mortality as well as body weight gain: PACAP(-/-) that survived >20 days of age with normal weight gain and PACAP(-/-) that died before 20 days with a marked weight loss. Kaplan-Meier survival analysis demonstrated that PACAP(-/-) mice and those carrying the PACAP transgene have similarly lower survival probability compared with their heterozygous littermates that served as positive controls. Further study using additional tissue-specific transgenic or knockout mouse models will be required to determine the causative defects underlying the high mortality of PACAP(-/-) mice. 相似文献
106.
107.
108.
Knockdown of the mitochondria‐localized protein p13 protects against experimental parkinsonism 下载免费PDF全文
Naoki Inoue Sae Ogura Atsushi Kasai Takanobu Nakazawa Kazuya Ikeda Shintaro Higashi Ayako Isotani Kousuke Baba Hideki Mochizuki Harutoshi Fujimura Yukio Ago Atsuko Hayata‐Takano Kaoru Seiriki Yusuke Shintani Norihito Shintani Hitoshi Hashimoto 《EMBO reports》2018,19(3)
Mitochondrial dysfunction in the nigrostriatal dopaminergic system is a critical hallmark of Parkinson's disease (PD). Mitochondrial toxins produce cellular and behavioural dysfunctions resembling those in patients with PD. Causative gene products for familial PD play important roles in mitochondrial function. Therefore, targeting proteins that regulate mitochondrial integrity could provide convincing strategies for PD therapeutics. We have recently identified a novel 13‐kDa protein (p13) that may be involved in mitochondrial oxidative phosphorylation. In the current study, we examine the mitochondrial function of p13 and its involvement in PD pathogenesis using mitochondrial toxin‐induced PD models. We show that p13 overexpression induces mitochondrial dysfunction and apoptosis. p13 knockdown attenuates toxin‐induced mitochondrial dysfunction and apoptosis in dopaminergic SH‐SY5Y cells via the regulation of complex I. Importantly, we generate p13‐deficient mice using the CRISPR/Cas9 system and observe that heterozygous p13 knockout prevents toxin‐induced motor deficits and the loss of dopaminergic neurons in the substantia nigra. Taken together, our results suggest that manipulating p13 expression may be a promising avenue for therapeutic intervention in PD. 相似文献
109.
Masakazu Kataoka Norihito Kuno Takashi Horiguchi Tatsuji Seki Toshiomi Yoshida 《Molecular genetics and genomics : MGG》1994,242(2):130-136
The replication of the 11 kb conjugative multicopy Streptomyces plasmid pSN22 was analyzed. Mutation and complementation analyses indicated that the minimal region essential for plasmid replication was located on a 1.9 kb fragment of pSN22, containing a trans-acting element encoding a replication protein and a cis-acting sequence acting as a replication origin. Southern hybridization showed that minimal replicon plasmids accumulated much more single-stranded plasmid molecules than did wild-type pSN22. Only one strand was accumulated. A 500 by fragment from the pSN22 transfer region was identified which reduced the relative amount of single-stranded DNA, when added in the native orientation to minimal replicon plasmids. This 500 by DNA sequence may be an origin for second-strand synthesis. It had no effect on the efficiency of co-transformation, plasmid incompatibility, or stability. The results indicate that pSN22 replicates via single-stranded intermediates by a rolling circle mechanism. 相似文献
110.
Ueoka-Nakanishi H Hori N Ishida K Ono N Yamashino T Nakamichi N Mizuno T 《Bioscience, biotechnology, and biochemistry》2011,75(11):2148-2154
Sessile plants must continuously adjust their growth and development to optimize photosynthetic activity under ever-fluctuating light conditions. Among such light responses in plants, one of the best-characterized events is the so-called shade avoidance, for which a low ratio of the red (R):far-red (FR) light intensities is the most prominent stimulus. Such shade avoidance responses enable plants to overtop their neighbors, thereby enhancing fitness and competitiveness in their natural habitat. Considerable progress has been achieved during the last decade in understanding the molecular mechanisms underlying the shade avoidance responses in the model rosette plant, Arabidopsis thaliana. We characterize here the fundamental aspects of the shade avoidance responses in the model legume, Lotus japonicus, based on the fact that its phyllotaxis (or morphological architecture) is quite different from that of A. thaliana. It was found that L. japonicus displays the characteristic shade avoidance syndrome (SAS) under defined laboratory conditions (a low R:FR ratio, low light intensity, and low blue light intensity) that mimic the natural canopy. In particular, the outgrowth of axillary buds (i.e., both aerial and cotyledonary shoot branching) was severely inhibited in L. japonicus grown in the shade. These results are discussed with special emphasis on the unique aspects of SAS observed with this legume. 相似文献