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1.
Litman GW; Rast JP; Shamblott MJ; Haire RN; Hulst M; Roess W; Litman RT; Hinds- Frey KR; Zilch A; Amemiya CT 《Molecular biology and evolution》1993,10(1):60-72
Immunoglobulins are encoded by a large multigene system that undergoes
somatic rearrangement and additional genetic change during the development
of immunoglobulin-producing cells. Inducible antibody and antibody-like
responses are found in all vertebrates. However, immunoglobulin possessing
disulfide-bonded heavy and light chains and domain-type organization has
been described only in representatives of the jawed vertebrates. High
degrees of nucleotide and predicted amino acid sequence identity are
evident when the segmental elements that constitute the immunoglobulin gene
loci in phylogenetically divergent vertebrates are compared. However, the
organization of gene loci and the manner in which the independent elements
recombine (and diversify) vary markedly among different taxa. One striking
pattern of gene organization is the "cluster type" that appears to be
restricted to the chondrichthyes (cartilaginous fishes) and limits
segmental rearrangement to closely linked elements. This type of gene
organization is associated with both heavy- and light-chain gene loci. In
some cases, the clusters are "joined" or "partially joined" in the germ
line, in effect predetermining or partially predetermining, respectively,
the encoded specificities (the assumption being that these are expressed)
of the individual loci. By relating the sequences of transcribed gene
products to their respective germ-line genes, it is evident that, in some
cases, joined-type genes are expressed. This raises a question about the
existence and/or nature of allelic exclusion in these species. The
extensive variation in gene organization found throughout the vertebrate
species may relate directly to the role of intersegmental
(V<==>D<==>J) distances in the commitment of the individual
antibody-producing cell to a particular genetic specificity. Thus, the
evolution of this locus, perhaps more so than that of others, may reflect
the interrelationships between genetic organization and function.
相似文献
2.
Carvalho HF Felisbino SL Covizi DZ Della Colleta HH Gomes L 《Cell and tissue research》2000,300(3):435-446
The elastic tendon of the avian wing has been described by others as a unique structure with elastic properties due to the predominance of elastic fibers in the midsubstance. Further analyses of the tendon have shown it to possess five anatomically distinct regions. Besides the major elastic region, a distally located fibrocartilage and three tendinous regions are present. The tendinous regions connect: (1) the muscle to the elastic region, (2) the elastic region to the fibrocartilage and (3) the latter to the insertion site. The elastic region possesses thick and abundant elastic fibers and very thin, interconnecting collagen fibers. The collagen fibers in the sesamoid fibrocartilage are thick and interwoven, defining spaces occupied by fibrochondrocytes embedded in a non-fibrillar and highly metachromatic matrix. Biochemical analyses have shown that the fibrocartilage has about tenfold the amount of glycosaminoglycans (GAGs) found in the other regions. The main GAG in this region was chondroitin sulfate (CS) (plus keratan sulfate as detected immunocytochemically), while the other regions showed variable amounts of CS, dermatan sulfate (DS) and heparan sulfate. Further analyses have shown that a large CS-bearing proteoglycan is found in the fibrocartilage. The elastic region possesses two main proteoglycans, a large CS-bearing proteoglycan (which reacted with an antibody against keratan sulfate after chondroitinase ABC treatment) and a predominant DS-bearing proteoglycan, which showed immunoreactivity when assayed with an anti-biglycan antibody. The results demonstrate that the elastic tendon is a complex structure with complex regional structural and compositional adaptations, suited to different biomechanical roles. 相似文献
3.
Moreschi E Hernandes L Dantas JA da Silva MA Casaroto AR Bersani-Amado CA 《Histology and histopathology》2010,25(12):1547-1556
The aim of the present study was to evaluate histologically and radiographically the tissue response to dolomite [CaMg(CO3)2] and its osteogenic potential in the repair of bone cavities in the calvaria of rats. A bone defect 10 mm in diameter and 1 mm deep was made in the calvaria of male Wistar rats. The defects were filled with dolomite, inorganic bovine bone (positive control), or coagulum (negative control). The animals were euthanized 7, 15, 30, and 60 days after surgery, and specimens were collected for radiographic and microscopic analyses. The bone defects were processed for paraffin embedding and H&E staining. The histological study revealed that dolomite stimulated a moderate inflammatory response, with programmed cell death in the first 15 days, compared to bovine bone which showed a moderate to intense acute response. In the chronic phase, the inflammatory response was characterized by the occurrence of macrophages organized as epithelioid cells in the dolomite group, and giant cells in the bovine-bone group. Fibrosis developed in all three groups; however, encapsulation of the fragments, reabsorption, and osteoconductive activity occurred only in the defects filled with bovine bone. The radiographic analysis showed that the bovine bone was most efficient in the repair of the defects, followed by the dolomite and the coagulum. This study demonstrated that the dolomite stimulated a moderate acute inflammatory response with programmed cell death, and a chronic inflammatory response by means of the phagocytic mononuclear system. Although osteo-conductive activity was not shown, the dolomite favored the repair process, compared to the coagulum group. 相似文献
4.
Boaz G. Oliveira Maria C. A. Lima Ivan R. Pitta Suely L. Galdino Marcelo Z. Hernandes 《Journal of molecular modeling》2010,16(1):119-127
A theoretical study is presented with the aim to investigate the molecular properties of intermolecular complexes formed by
the monomeric units of polyvinylpyrrolidone (PVP) or polyethyleneglycol (PEG) polymers and a set of four imidazolidine (hydantoine)
derivatives. The substitution of the carbonyl groups for thiocarbonyl in the hydantoin scaffold was taken into account when
analyzing the effect of the hydrogen bonds on imidazolidine derivatives. B3LYP/6-31G(d,p) calculations and topological integrations
derived from the quantum theory of atoms in molecules (QTAIM) were applied with the purpose of examining the N–H⋯O hydrogen
bond strengths formed between the amide group of the hydantoine ring and the oxygen atoms of PVP and PEG polymers. The effects
caused by the N–H⋯O interaction fit the typical evidence for hydrogen bonds, which includes a variation in the stretch frequencies
of the N–H bonds. These frequencies were identified as being vibrational red-shifts because their values decreased. Although
the values of such calculated interaction energies are between 12 and 33 kJ mol−1, secondary intermolecular interactions were also identified. One of these secondary interactions is formed through the interaction
of the benzyl hydrogen atoms with the oxygen atoms of the PVP and PEG structures. As such, we have analyzed the stretch frequencies
on the C–H bonds of the benzyl groups, and blue-shifts were identified on these bonds. In this sense, the intermolecular systems
formed by hydantoine derivatives and PVP/PEG monomers were characterized as a mix of red-shifting and blue-shifting hydrogen-bonded
complexes. 相似文献
5.
Estrogen seems to have an essential role in the fibromuscular growth characteristic of benign prostatic hyperplasia (BPH). This paper describes the effects of chronic estradiol treatment on Guinea pig prostatic stroma at different ages. Tissues from experimental animals were studied by histological and histochemical procedures, morphometric-stereological analysis and transmission electron microscopy (TEM). Marked fibromuscular hypertrophy was observed after estradiol treatment in animals of pre-pubertal and adult ages. Increases in the density and thickness of the collagen and elastic fibers were observed by histochemistry. TEM revealed wide distributions of collagen fibrils and large elastic fibers adjacent to the epithelial basal lamina and between the stromal cells, establishing contacts between them. These results indicate that the Guinea pig prostate simulates the stromal modifications observed in BPH in some aged animals after estrogen treatment at different ages, making it a good model for this disease. 相似文献
6.
An unambiguous, fully ab initio and automated technique denoted AIPAR (ab initio parametrization) implemented in the SJBR program has been proposed to yield intermolecular interaction potentials between polar molecules and water. The AIPAR procedure has been applied to several organic molecules covering a wide range of structure and functional groups, namely methanol, acetone (propanone), methanethiol (methyl mercaptan), imidazole (1,3-diazole), oxazole and furan. The AIPAR-derived sets of parameters compare well with the empirical OPLS ones, mainly when the all-atoms model is employed in the OPLS procedure. Monte Carlo simulations were performed for an aqueous solution of methanol and for an equimolar binary mixture methanol–water using the AIPAR and OPLS parameters. The thermodynamic and geometric results obtained with the parameters obtained with the AIPAR procedure compare favorably with the OPLS simulations, even for the binary mixture, demonstrating the precision, robustness and transferability of the parameters obtained with the AIPAR procedure.Figure Superimposed configurations of water (without the hydrogen atoms) around the methanol molecule obtained with the AGOA procedure. 相似文献
7.
Cleiton Diniz Barros Angélica Amorim Amato Tiago Bento de Oliveira Karime Bicas Rocha Iannini Anekécia Lauro da Silva Teresinha Gonçalves da Silva Elisa Soares Leite Marcelo Zaldini Hernandes Maria do Carmo Alves de Lima Suely Lins Galdino Francisco de Assis Rocha Neves Ivan da Rocha Pitta 《Bioorganic & medicinal chemistry》2010,18(11):3805-3811
Eight new 5-arylidene-3-benzyl-thiazolidine-2,4-diones with halide groups on their benzyl rings were synthesized and assayed in vivo to investigate their anti-inflammatory activities. These compounds showed considerable biological efficacy when compared to rosiglitazone, a potent and well-known agonist of PPARγ, which was used as a reference drug. This suggests that the substituted 5-arylidene and 3-benzylidene groups play important roles in the anti-inflammatory properties of this class of compounds. Docking studies with these compounds indicated that they exhibit specific interactions with key residues located in the site of the PPARγ structure, which corroborates the hypothesis that these molecules are potential ligands of PPARγ. In addition, competition binding assays showed that four of these compounds bound directly to the ligand-binding domain of PPARγ, with reduced affinity when compared to rosiglitazone. An important trend was observed between the docking scores and the anti-inflammatory activities of this set of molecules. The analysis of the docking results, which takes into account the hydrophilic and hydrophobic interactions between the ligands and the target, explained why the 3-(2-bromo-benzyl)-5-(4-methanesulfonyl-benzylidene)-thiazolidine-2,4-dione compound had the best activity and the best docking score. Almost all of the stronger hydrophilic interactions occurred between the substituted 5-arylidene group of this compound and the residues of the binding site. 相似文献
8.
Tendon composition changes according to differentiation, mechanical load, and aging. In this study, we attempted to identify, localize, and quantify type VI collagen in bovine tendons. Type VI collagen was identified by the electrophoretic behavior of the alpha chains and Western blotting, and by rotary shadowing. Type VI collagen was extracted from powdered tendon with three sequential 24-h extractions with 4 M guanidine-HCl. The amount of type VI collagen was determined by enzyme-linked immunosorbent assay for purely tensional areas and for the compressive fibrocartilage regions of the deep flexor tendon of the digits, for the corresponding fetal and calf tendons, and for the extensor digital tendon. The distal fibrocartilaginous region of the adult tendon was richer in type VI collagen than the tensional area, reaching as much as 3.3 mg/g (0.33%) of the wet weight. Calf tendons showed an accumulation of type VI at the fibrocartilage site. Immunocytochemistry demonstrated that type VI collagen was evenly distributed in the tensional areas of tendons but was highly concentrated around the fibrochondrocytes in the fibrocartilages. The results demonstrate that tendons are variable with regard to the presence and distribution of type VI collagen. The early accumulation of type VI collagen in the region of calf tendon that will become fibrocartilage in the adult suggests that it is a good marker of fibrocartilage differentiation. Furthermore, the distribution of type VI collagen in tendon fibrocartilage indicates that it organizes the pericellular environment and may represent a survival factor for these cells. 相似文献
9.
Silva JA Ferrucci DL Peroni LA Abrahão PG Salamene AF Rossa-Junior C Carvalho HF Stach-Machado DR 《Journal of cellular physiology》2012,227(6):2441-2450
Molecular mechanisms responsible for periodontal disease (PD) and its worsening in type 1 Diabetes Mellitus (DM1) remain unknown. Cytokine profile and expression levels of collagenases, Mmp14, and tissue inhibitors were determined, as were the numbers of neutrophils and macrophages in combined streptozotocin-induced DM1 and ligature-induced PD models. Increased IL-23 (80-fold) and Mmp8 expression (25-fold) was found in DM1. Ligature resulted in an IL-1β/IL-6 profile, increased expression of Mmp8, Mmp13, and Mmp14 (but not Mmp1), and transient expression of Timp1 and Reck in non-diabetics. PD in DM1 involved IL-1β (but not IL-6) and IL-23/IL-17, reduced IL-6 and IL-10, sustained Mmp8 and Mmp14, increased Mmp13 and reduced Reck expression in association with 20-fold higher counts of neutrophils and macrophages. IL-23 and Mmp8 expression are hallmarks of DM1. In association with the IL-1/IL-6 (Th1) response in PD, one found a secondary IL-17 (Th17) pathway in non-diabetic rats. Low IL-6/TNF-α suggest that the Th1 response was compromised in DM1, while IL-17 indicates a prevalence of the Th17 pathway, resulting in high neutrophil recruitment. Mmp8, Mmp13, and Mmp14 expression seems important in the tissue destruction during PD in DM1. PD-associated IL-1/IL-6 (Th1), IL-10, and Reck expression are associated with the acute-to-chronic inflammation transition, which is lost in DM1. In conclusion, IL-23/IL-17 are associated with the PD progression in DM1. 相似文献
10.
The suitability of rubber tree clones to Calacarus heveae was inferred from the life cycle, reproduction and survivorship of this mite. The assays were performed under controlled
conditions with leaflets detached from 6-year-old plants. The development of 20 C. heveae individuals on each of the clones GT 1, PB 235 and RRIM 600 was analysed. This experiment was performed four times during
periods when C. heveae was abundant in the field: (P1) November–December 2005, (P2) January–February, (P3) March–April and (P4) May–June 2006. Accordingly,
the leaflets used in each assay represented the physiological condition of the host plant during each period. This approach
allowed us to evaluate the seasonal suitability of rubber tree clones to C. heveae. We observed seasonal differences in the suitability of rubber tree clones to mite attack. The mites reared on the PB235
had a shorter development period, the highest egg production and highest survivorship. This evidence showed that the PB 235
was the most suitable of those tested. We also observed that the leaflets used in the assays during periods P2 and P3 were
the most favourable for the development of C. heveae. This finding emphasises the seasonal suitability of rubber tree leaflets. On the other hand, GT 1 showed higher resistance
against C. heveae than did RRIM 600 and PB 235, primarily during the period from November to February. This result indicated that use of the
GT 1 clone to control the mite might represent an alternative for growers. 相似文献