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971.
Exposure of biological materials to ionizing radiation often induces clustered DNA damage. The mutagenicity of clustered DNA damage can be analyzed with plasmids carrying a clustered DNA damage site, in which the strand bias of a replicating plasmid (i.e., the degree to which each of the two strands of the plasmid are used as the template for replication of the plasmid) can help to clarify how clustered DNA damage enhances the mutagenic potential of comprising lesions. Placement of a mismatch near a clustered DNA damage site can help to determine the strand bias, but present plasmid-based methods do not allow insertion of a mismatch at a given site in the plasmid. Here, we describe a polymerization-based method for constructing a plasmid containing clustered DNA lesions and a mismatch. The presence of a DNA lesion and a mismatch in the plasmid was verified by enzymatic treatment and by determining the relative abundance of the progeny plasmids derived from each of the two strands of the plasmid. 相似文献
972.
Takashi Nobusawa Misaki Kamei Hiroaki Ueda Naoya Matsushima Hiroshi Yamatani Makoto Kusaba 《Plant physiology》2021,186(1):767
The cytochrome P450 CYP78A5/KLUH in Arabidopsis thaliana is predicted to be involved in the synthesis of a mobile signal molecule that has a pleiotropic function that is distinct from classical phytohormones. CYP78A5 has five close relatives in Arabidopsis. We first investigated their functions, focusing on the plastochron, leaf size, and leaf senescence. Our analyses revealed that CYP78A5 and CYP78A7 are involved in the plastochron and leaf size, and CYP78A6 and CYP78A9 are involved in leaf senescence. Complementation analyses using heterologous promoters and expression analyses suggested that CYP78A isoforms have a common biochemical function and are functionally differentiated via organ-specific expression. The altered meristem program1 (amp1) carboxypeptidase mutant shows a phenotype very similar to that of the cyp78a5 mutant. Complementation analyses using boundary and organizing center-specific promoters suggested that both CYP78A5 and AMP1 act in a non-cell-autonomous manner. Analyses of multiple cyp78a mutants and crosses between cyp78a and amp1 mutants revealed that AMP1/LIKE AMP1 (LAMP1) and CYP78A isoforms regulate plastochron length and leaf senescence in the same genetic pathway, whereas leaf size is independently regulated. Furthermore, we detected feedback regulation between CYP78A6/CYP78A9 and AMP1 at the gene expression level. These observations raise the possibility that AMP1 and CYP78A isoforms are involved in the synthesis of the same mobile signal molecule, and suggest that AMP1 and CYP78A signaling pathways have a very close, albeit complex, functional relationship.ALTERED MERISTEM PROGRAM1 and isoforms of the cytochrome P450 CYP78A regulate plastochron and leaf senescence in non-cell-autonomous/organ-specific manners, and have a close, albeit complex, and functional relationship. 相似文献
973.
Yoshiyuki Sasajima Yusuke Kohama Miki Kojima-Misaizu Naoya Kurokawa Yuko Hara Jinhua Dong Masaki Ihara Hiroshi Ueda 《Molecular biotechnology》2014,56(10):953-961
Alkaline phosphatases (APs) are a family of dimeric metalloenzymes that has been utilized in many areas due to its ability to hydrolyze a variety of phosphomonoesters. While mammalian APs have higher specific activity than prokaryotic APs, they are generally less thermostable. To cultivate the possibility to confer mammalian APs with higher thermostability as well as high activity, we focused on human AP isozymes. Among the four isozymes of human APs, placental AP (PLAP) retains the highest thermostability, while intestinal AP (IAP) has the highest specific activity. Since the two APs display high homology, a series of chimeric enzymes were made in a secreted form to analyze their properties. Surprisingly, chimeric APs with IAP residues at the N-terminal and PLAP residues at the C-terminal regions showed higher specific activity than PLAP, while keeping thermostability as high as PLAP. Especially, one showed similar specific activity to IAP, while showing slower inactivation than PLAP after incubation at 75 °C. Interestingly, the mutant also showed higher resistance to uncompetitive inhibitors Phe and Leu than their parent enzymes, possibly due to increased hydrophilicity of the active site entrance residues. The obtained chimera will be useful as a novel reporter in various assays including gene hybridization. 相似文献
974.
Jing Wang Naoya Tochio Aya Takeuchi Jun-ichi Uewaki Naohiro Kobayashi Shin-ichi Tate 《Biochemical and biophysical research communications》2013
HMGB1 (high-mobility group B1) is a ubiquitously expressed bifunctional protein that acts as a nuclear protein in cells and also as an inflammatory mediator in the extracellular space. HMGB1 changes its functions according to the redox states in both intra- and extra-cellular environments. Two cysteines, Cys23 and Cys45, in the A-domain of HMGB1 form a disulfide bond under oxidative conditions. The A-domain with the disulfide bond shows reduced affinity to cisplatin modified DNA. We have solved the oxidized A-domain structure by NMR. In the structure, Phe38 has a flipped ring orientation from that found in the reduced form; the phenyl ring in the reduced form intercalates into the platinated lesion in DNA. The phenyl ring orientation in the oxidized form is stabilized through intramolecular hydrophobic contacts. The reorientation of the Phe38 ring by the disulfide bond in the A-domain may explain the reduced HMGB1 binding affinity towards cisplatinated DNA. 相似文献
975.
Yuka Koyama Katsuyoshi Matsunami Hideaki Otsuka Takakazu Shinzato Yoshio Takeda 《Phytochemistry》2010,71(5-6):675-681
From a 1-BuOH-soluble fraction of a MeOH extract of the leaves of Microtropis japonica, collected in the Okinawa islands, six ent-labdane glucosides, named microtropiosides A–F, were isolated together with one known acyclic sesquiterpene glucoside. Their structures were elucidated by a combination of spectroscopic analyses, and their absolute configurations determined by application of the β-d-glucopyranosylation-induced shift-trend rule in 13C NMR spectroscopy and the modified Mosher’s method. 相似文献
976.
Yamaya Tomoyuki; Tanno Hiromi; Hirose Naoya; Watanabe Sachiko; Hayakawa Toshihiko 《Plant & cell physiology》1995,36(7):1197-1204
When rice seedlings, after the growth for 26 days in water alone,were transferred to nutrient medium contained 1 mM NH4Cl, thelevel of NADH-dependent glutamate synthase (GOGAT) protein andthe activity of the enzyme increased more than 10-fold in root,but not in shoots. Both the level of the protein and the activityreached a maximum within 24 h. NH4Cl was effective at concentrationsas low as 50 µM. A supply of either 1 mM NaNO3 or 0.5mM NH4NO3 also caused such increases, but NHa4Cl was most effective.A supply of glutamine or glutamate was less effective. The increasewas specific to NADH-GOGAT and little change was observed inthe levels of ferredoxin-GOGAT and glutamine synthetase isoproteinsin roots. These inducible increases in the levels of NADH-GOGATprotein and in its activity were greater in the root-tip regionthan at the base of the root. Both 6-methylpurine and cycloheximidecompletely inhibited the effects of NH4Cl. Moreover, the mRNAfor NADH-GOGAT in rice roots accumulated markedly within 12h of the start of a supply of NH4Cl. A possible role for therapid response of NADH-GOGAT to a supply of NH4C1 is discussed. (Received May 18, 1995; Accepted July 10, 1995) 相似文献
977.
Sickle cell disease (SCD) is one of the most common life-threatening monogenic diseases affecting millions of people worldwide. Allogenic hematopietic stem cell transplantation is the only known cure for the disease with high success rates, but the limited availability of matched sibling donors and the high risk of transplantation-related side effects force the scientific community to envision additional therapies. Ex vivo gene therapy through globin gene addition has been investigated extensively and is currently being tested in clinical trials that have begun reporting encouraging data. Recent improvements in our understanding of the molecular pathways controlling mammalian erythropoiesis and globin switching offer new and exciting therapeutic options. Rapid and substantial advances in genome engineering tools, particularly CRISPR/Cas9, have raised the possibility of genetic correction in induced pluripotent stem cells as well as patient-derived hematopoietic stem and progenitor cells. However, these techniques are still in their infancy, and safety/efficacy issues remain that must be addressed before translating these promising techniques into clinical practice. 相似文献
978.
Siyu Chen Yoshiyuki Manabe Naoya Minamoto Naoka Saiki 《Bioscience, biotechnology, and biochemistry》2016,80(10):1874-1878
We have elucidated the cooperative stabilization of proteins by sugars, amino acids, and other protein-stabilizing agents using a new and simple assay system. Our system determines the protein-stabilizing ability of various compounds by measuring their ability to protect hemoglobin from denaturation. Hemoglobin denaturation was readily measured by quantitative changes in its ultraviolet–visible absorption spectrum. The efficiency of our assay was confirmed using various sugars such as trehalose and sucrose that are known to be good protein stabilizers. We have also found that mixtures of two different types of protein stabilizers resulted in a cooperative stabilizing effect on protein. 相似文献
979.
How do environmental factors influence life cycles and development? An experimental framework for early‐diverging metazoans
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Thomas C. G. Bosch Maja Adamska René Augustin Tomislav Domazet‐Loso Sylvain Foret Sebastian Fraune Noriko Funayama Juris Grasis Mayuko Hamada Masayuki Hatta Bert Hobmayer Kotoe Kawai Alexander Klimovich Michael Manuel Chuya Shinzato Uli Technau Seungshic Yum David J. Miller 《BioEssays : news and reviews in molecular, cellular and developmental biology》2014,36(12):1185-1194
980.