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51.
Several cultural techniques were tested for establishment of nitrogen fixing soybeans on heavy-clay, acid sulfate soils of different fertility at two locations. Holes of 2.5 cm deep were made by inserting a pointed pole into the surface soil. Soybean seeds were dropped into the holes and covered with either (i) Rhizobium inoculant, molybdenum (0.5 kg Mo/ha) and ash from burned rice husks (0.2 t/ha) or (ii) Rhizobium inoculant, molybdenum and local soil instead of the ash. Additional treatments evaluated were the use or absence of tillage and the presence or absence of a rice straw mulch (5 t/ha). Soybean plants treated with ash had the highest number of nodules per plant. The combination of mulching and ash treatments produced the highest soybean grain yields. Without ash all treatments produced low grain yields. Tillage had no effect.  相似文献   
52.
In this study, a novel three-compartmented electrochemical bioreactor (3-CEB) was designed in an effort to overcome the disadvantages of the two-compartmented electrochemical bioreactor (2-CEB) separated with a cation-selective membrane for enrichment of strict anaerobes. The 3-CEB was comprised of an anode, outlet, and a cathode compartment. The outlet compartment was positioned between the anode and cathode compartment, and it was separated with the anode side by a rubber plate and with the cathode side by a porous glass membrane. A platinum wire bridging the anode and outlet compartment operated as a redox passage, however, through which no material could permeate. Butyrate fermentation bacteria were enriched on the basis of the metabolite production. Butyrate generated by strict anaerobes was significantly more abundant in the 3-CEB than in the 2-CEB. Acetic acid and lactic acid generated by facultative anaerobes was relatively higher in the 2-CEB than in the 3-CEB. Meanwhile, butyrate was not generated in the bioreactor utilized for the control test, to which the electrochemical potential was not charged. In a continuous culture using the 3-CEB, the majority of the glucose was fermented to butyrate, and the acetate additionally supplied to the bacterial culture was metabolically reduced to butyrate. More lactate than butyrate was generated from glucose in the 2-CEB.  相似文献   
53.
Applied Microbiology and Biotechnology - Streptomyces peucetius ATCC 27952 produces two major anthracyclines, doxorubicin (DXR) and daunorubicin (DNR), which are potent chemotherapeutic agents for...  相似文献   
54.
Cat eye syndrome (CES) is a developmental disorder with multiple organ involvement, associated with the duplication of a 2-Mb region of 22q11.2. Using exon trapping and genomic sequence analysis, we have isolated and characterized a gene, CECR1, that maps to this critical region. The protein encoded by CECR1 is similar to previously identified novel growth factors: IDGF from Sarcophaga peregrina (flesh fly) and MDGF from Aplysia californica (sea hare). The CECR1 gene is alternatively spliced and expressed in numerous tissues, with most abundant expression in human adult heart, lung, lymphoblasts, and placenta as well as fetal lung, liver, and kidney. In situ hybridization of a human embryo shows specific expression in the outflow tract and atrium of the developing heart, the VII/VIII cranial nerve ganglion, and the notochord. The location of this gene in the CES critical region and its embryonic expression suggest that the overexpression of CECR1 may be responsible for at least some features of CES, particularly the heart defects.  相似文献   
55.
In mammalian cells, 8-oxoguanine DNA glycosylase-1 (OGG1) is the main DNA glycosylase for the removal of 8-oxoguanine (8-oxoG). 8-oxoG, one of the most common products of the oxidative attack of DNA, is a premutagenic lesion that accumulates spontaneously at high frequencies in the genome. In this study, Ogg1 mRNA expression was detected throughout embryonic development in mice. In situ hybridization showed that in the neonatal brain, Ogg1 expression was detected in a distinct layer of cells in the medial wall of the lateral ventricle, which may correspond to ependymal cells, and in some scattered cells in the subventricular zone (SVZ), a brain region rich in neural stem/progenitor cells. Using neurospheres as a model for the study of neural stem/progenitor cells, we found that both the expression and activity of Ogg1 were high in neurospheres derived from newborn mice and decreased in adults and upon induction of cell differentiation. Furthermore, Ogg1 was shown to be the major DNA glycosylase initiating 8-oxoG repair in neurospheres. Our results strongly indicate that enhanced DNA repair capacity is an important mechanism by which neural stem/progenitor cells maintain their genome.  相似文献   
56.
Down-regulation of quorum-sensing based pathways is an important but yet poorly understood process in bacterial gene regulation. In this study, we show that the gene regulator plnC not only acts as an activator gene in the quorum-sensing based bacteriocin production in Lactobacillus plantarum C11, but it also concurrently codes for truncated forms that were shown to repress bacteriocin production. By amino acid N-terminal sequencing and DNA sequence analysis, the truncated species of PlnC are believed to be translated from alternative start codons located in the so-called receiver domain of the regulator. To analyse the structure–function relationship of truncated species of PlnC, we performed a series of systematic truncation mutations: ten in the receiver domain, one in the hinge region and two in the C-terminal DNA-binding domain. It was revealed that any truncation mutation containing a disrupted receiver domain together with an intact DNA-binding domain displayed a repressive effect on bacteriocin production. Such a gene repression mechanism mediated by truncated regulators was also found in two other quorum-sensing based bacteriocin systems (spp in L. sakei LTH673 and NC8-pln in L. plantarum NC8), suggesting that this mode of repression might represent a common means applied by bacteria to down-regulate certain quorum-sensing based pathways. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
57.
We present here the x-ray structures of the progesterone receptor (PR) in complex with two mixed profile PR modulators whose functional activity results from two differing molecular mechanisms. The structure of Asoprisnil bound to the agonist state of PR demonstrates the contribution of the ligand to increasing stability of the agonist conformation of helix-12 via a specific hydrogen-bond network including Glu(723). This interaction is absent when the full antagonist, RU486, binds to PR. Combined with a previously reported structure of Asoprisnil bound to the antagonist state of the receptor, this structure extends our understanding of the complex molecular interactions underlying the mixed agonist/antagonist profile of the compound. In addition, we present the structure of PR in its agonist conformation bound to the mixed profile compound Org3H whose reduced antagonistic activity and increased agonistic activity compared with reference antagonists is due to an induced fit around Trp(755), resulting in a decreased steric clash with Met(909) but inducing a new internal clash with Val(912) in helix-12. This structure also explains the previously published observation that 16α attachments to RU486 analogs induce mixed profiles by altering the binding of 11β substituents. Together these structures further our understanding of the steric and electrostatic factors that contribute to the function of steroid receptor modulators, providing valuable insight for future compound design.  相似文献   
58.
A comprehensive, unbiased inventory of synuclein forms present in Lewy bodies from patients with dementia with Lewy bodies was carried out using two-dimensional immunoblot analysis, novel sandwich enzyme-linked immunosorbent assays with modification-specific synuclein antibodies, and mass spectroscopy. The predominant modification of alpha-synuclein in Lewy bodies is a single phosphorylation at Ser-129. In addition, there is a set of characteristic modifications that are present to a lesser extent, including ubiquitination at Lys residues 12, 21, and 23 and specific truncations at Asp-115, Asp-119, Asn-122, Tyr-133, and Asp-135. No other modifications are detectable by tandem mass spectrometry mapping, except for a ubiquitous N-terminal acetylation. Small amounts of Ser-129 phosphorylated and Asp-119-truncated alpha-synuclein are present in the soluble fraction of both normal and disease brains, suggesting that these Lewy body-associated forms are produced during normal metabolism of alpha-synuclein. In contrast, ubiquitination is only detected in Lewy bodies and is primarily present on phosphorylated synuclein; it therefore likely occurs after phosphorylated synuclein has deposited into Lewy bodies. This invariant pattern of specific phosphorylation, truncation, and ubiquitination is also present in the detergent-insoluble fraction of brain from patients with familial Parkinson's disease (synuclein A53T mutation) as well as multiple system atrophy, suggesting a common pathogenic pathway for both genetic and sporadic Lewy body diseases. These observations are most consistent with a model in which preferential accumulation of normally produced Ser-129 phosphorylated alpha-synuclein is the key event responsible for the formation of Lewy bodies in various Lewy body diseases.  相似文献   
59.
During the process of spindle-chromosome complex depletion in the oocyte, it is unclear whether both gamma-tubulin and nuclear mitotic apparatus protein 1 (NUMA1), which are required for mitotic organization and spindle assembly, are removed. The role of the donor cell centrosome and donor nuclear NUMA1 in the initial spindle morphogenesis and chromosome remodeling also remains unclear. In the present study, we show that in the mouse, the level of gamma-tubulin in the poles and around the metaphase II spindle declines significantly, whereas only approximately 10% of NUMA1 is removed during spindle-chromosome complex depletion in the recipient oocyte. This process does not impede initial spindle morphogenesis and is regulated by the centrosome of the donor cumulus cell. Retaining the donor cell centrosome establishes a monopolar spindle, whereas prior removal of the centrosome by a narrow-bore micropipette leads to bipolar spindle formation. Our data show that the centrosome of the donor cell regulates initial spindle morphogenesis and that the donor cumulus cell NUMA1 compensates for the deficiency in recipient NUMA1 during the formation of metaphase-like structures after nuclear transfer. Full-term offspring of cloned mice were obtained after injection of donor cells only with a pipette having an inner diameter of 7-8 microm, which retained the donor cell centrosome. In contrast, removing the donor cell centrosome with a small pipette impaired preimplantation development and prevented full-term development. In conclusion, the initial spindle assembly of a metaphase-like spindle is regulated by the centrosome from the donor cell in the mouse.  相似文献   
60.
Intracellular malaria parasites require lipids for growth and replication. They possess a prokaryotic type II fatty acid synthesis (FAS II) pathway that localizes to the apicoplast plastid organelle and is assumed to be necessary for pathogenic blood stage replication. However, the importance of FAS II throughout the complex parasite life cycle remains unknown. We show in a rodent malaria model that FAS II enzymes localize to the sporozoite and liver stage apicoplast. Targeted deletion of FabB/F , a critical enzyme in fatty acid synthesis, did not affect parasite blood stage replication, mosquito stage development and initial infection in the liver. This was confirmed by knockout of FabZ , another critical FAS II enzyme. However, FAS II-deficient Plasmodium yoelii liver stages failed to form exo-erythrocytic merozoites, the invasive stage that first initiates blood stage infection. Furthermore, deletion of FabI in the human malaria parasite Plasmodium falciparum did not show a reduction in asexual blood stage replication in vitro . Malaria parasites therefore depend on the intrinsic FAS II pathway only at one specific life cycle transition point, from liver to blood.  相似文献   
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