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251.
HMGB1 expression and release by bone cells 总被引:5,自引:0,他引:5
Charoonpatrapong K Shah R Robling AG Alvarez M Clapp DW Chen S Kopp RP Pavalko FM Yu J Bidwell JP 《Journal of cellular physiology》2006,207(2):480-490
Immune and bone cells are functionally coupled by pro-inflammatory cytokine intercellular signaling networks common to both tissues and their crosstalk may contribute to the etiologies of some immune-associated bone pathologies. For example, the receptor activator of NF-kappaB ligand (RANKL)/osteoprotegerin (OPG)/receptor activator of NF-kappaB (RANK) signaling axis plays a critical role in dendritic cell (DC) function as well as bone remodeling. The expression of RANKL by immune cells may contribute to bone loss in periodontitis, arthritis, and multiple myeloma. A recent discovery reveals that DCs release the chromatin protein high mobility group box 1 (HMGB1) as a potent immunomodulatory cytokine mediating the interaction between DCs and T-cells, via HMGB1 binding to the membrane receptor for advanced glycation end products (RAGE). To determine whether osteoblasts or osteoclasts express and/or release HMGB1 into the bone microenvironment, we analyzed tissue, cells, and culture media for the presence of this molecule. Our immunohistochemical and immunocytochemical analyses demonstrate HMGB1 expression in primary osteoblasts and osteoclasts and that both cells express RAGE. HMGB1 is recoverable in the media of primary osteoblast cultures and cultures of isolated osteoclast precursors and osteoclasts. Parathyroid hormone (PTH), a regulator of bone remodeling, attenuates HMGB1 release in cultures of primary osteoblasts and MC3T3-E1 osteoblast-like cells but augments this release in the rat osteosarcoma cell line UMR 106-01, both responses primarily via activation of adenylyl cyclase. PTH-induced HMGB1 discharge by UMR cells exhibits similar release kinetics as reported for activated macrophages. These data confirm the presence of the HMGB1/RAGE signaling axis in bone. 相似文献
252.
H. Fredrick Vernay Eliezer S. Rachaman Ronald Eby Conrad Schuerch 《Carbohydrate research》1980,78(2):267-273
Several 1-O-sulfonyl derivatives of d-galactopyranose having a participating benzoyl or p-methoxybenzoyl group at O-2 were synthesized from the corresponding d-galactopyranosyl chloride derivatives by use of silver p-toluenesulfonate or trifluoroethanesulfonate in acetonitrile. The reaction of the derivatives with several alcohols in various solvents at different times and temperatures served as model reactions to determine the best conditions for synthesizing stereoselectively β-d-galactopyranosides in high yields. This method was used to prepare, in good yield, several β-d-galactopyranosyl-containing disaccharides. 相似文献
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255.
Technical note: Modeling primate occlusal topography using geographic information systems technology
L. Flynn Zuccotti Malcolm D. Williamson W. Fredrick Limp Peter S. Ungar 《American journal of physical anthropology》1998,107(1):137-142
Most functional analyses of primate tooth form have been limited to linear or area measurements. Such studies have offered but a limited glimpse at differences in occlusal relief among taxa. Such differences in dental topography may relate to tooth function and, so, have considerable implications for the inference of diet from fossil teeth. In this article, we describe a technique to model and compare primate molars in three dimensions using Geographic Resources Analysis Support System (GRASS) software. We examine unworn lower second molars of three extant hominoids with known differences in diet (Gorilla gorilla, Pan troglodytes, and Pongo pygmaeus), and two fossil forms, (Afropithecus turkanesis and Dryopithecus laietanus). First, we obtained approximately 400 landmarks on the occlusal surfaces of each tooth using an electromagnetic digitizer. Raster “terrain models” of occlusal surfaces were then created by interpolation of the coordinate data. We used GRASS terrain analysis automated techniques to quantify the volumes and slopes of individual cusps. We also used the GRASS watershed technique to identify the volume of liquid that would accumulate in each tooth's basin (a measure of basin area), and the directions and intensity of drainage over the occlusal surface. In sum, GRASS shows considerable potential for the characterization and comparison of tooth surfaces. Furthermore, techniques described here are not limited to the study of teeth, but may be broadly applicable to studies of skulls, joints, and other biological structures. Am J Phys Anthropol 107:137–142, 1998. © 1998 Wiley-Liss, Inc. 相似文献
256.
Agnes Nanyonjo Fredrick Makumbi Patrick Etou G?ran Tomson Karin K?llander for the inSCALE study group 《PloS one》2013,8(11)
Objective
To compare caretakers’ perceived quality of care (PQC) for under-fives treated for malaria, pneumonia and diarrhoea by community health workers (CHWs) and primary health facility workers (PHFWs).Methods
Caretaker rated PQC for children aged (2-59) months treated by either CHWs or PHFWs for a bought of malaria, pneumonia or diarrhoea was cross-sectionally compared in quality domains of accessibility, continuity, comprehensiveness, integration, clinical interaction, interpersonal treatment and trust. Child samples were randomly drawn from CHW (419) and clinic (399) records from eight Midwestern Uganda districts. An overall PQC score was predicted through factor analysis. PQC scores were compared for CHWs and PHFWs using Wilcoxon rank-sum test. Multinomial logistic regression models were used to specify the association between categorized PQC and service providers for each quality domain. Finally, overall PQC was dichotomized into “high” and “low” based on median score and relative risks (RR) for PQC-service provider association were modeled in a “modified” Poisson regression model.Results
Mean (SD) overall PQC was significantly higher for CHWs 0.58 (0 .66) compared to PHFWs -0.58 (0.94), p<0.0001. In “modified” Poisson regression, the proportion of caretakers reporting high PQC was higher for CHWS compared to PHFWs, RR=3.1, 95%CI(2.5-3.8). In multinomial models PQC was significantly higher for CHWs compared to PHFWs in all domains except for continuity.Conclusion
PQC was significantly higher for CHWs compared to PHFWs in this resource constrained setting. CHWs should be tapped human resources for universal health coverage while scaling up basic child intervention as PQC might improve intervention utilization. 相似文献257.
Paul W. Webala George Muriuki Fredrick Lala Alice Bett 《African Journal of Ecology》2006,44(3):363-370
Species richness and diversity of rodents and insectivores were investigated at relict forest patches of Mukogodo, Laikipia, Kenya using Sherman's live traps and pitfall traps. Two hundred and nineteen individuals were captured in 3021 trap‐nights. There were eleven species in two taxonomic groups, Rodentia and Insectivora. Two other rodent species were sighted but not captured. Thirteen bats belonging to four species (Epomophorous wahlbergi, Pipistrellus kuhlii, Scotophilus dingani and Nycteris thebaica) were opportunistically trapped using mist nets. Two of the four species accumulation curves for forest patches did not reach an asymptote. Species richness and diversity were highest at Kurikuri compared with other patches because of habitat variability. The results support the prediction that forest disturbance and degradation lead to an increase in generalist species as compared with specialists and highlight the importance of relict afromontane forests in the conservation of small mammals in Kenya. 相似文献
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259.
Fredrick Van Goor Jeffrey I. Goldberg Anderson O. L. Wong Richard M. Jobin John P. Chang 《Cell and tissue research》1994,276(2):253-261
To better understand neuroendocrine regulation and the intracellular mechanisms mediating pituitary-hormone release, it is necessary to study the physiology of identified single cells. We have developed a system to identify gonadotropin, growth-hormone, and prolactin cells in primary cultures of goldfish pituitary cells. Using Nomarski differential interference-contrast microscopy, the unique morphologies of discrete subpopulations of cells were characterized. To aid in the initial characterization of different pituitary-cell types, a discontinuous Percoll density-gradient cell-separation technique was developed. This method provided fractions enriched with functional gonadotropin, growth-hormone, and prolactin cells. The morphology of each cell type was initially characterized in enriched fractions of immunofluorescently labelled cells using differential interference-contrast microscopy. The cell type-specific morphologies were then confirmed in live pituitary-cell cultures. Gonadotropin, growth-hormone, and prolactin cells were correctly identified in live pituitary-cell cultures. Gonadotropin, growth-hormone, and prolactin cells were correctly identified in live mixed cultures in 92, 94, and 100% of the trials, respectively. The ability to directly identify cells in primary cultures allows the physiological study of identified single cells with minimal pretreatment. 相似文献
260.
Frederick Haraka Tracy R. Glass George Sikalengo Anna Gamell Alex Ntamatungiro Christoph Hatz Marcel Tanner Hansjakob Furrer Manuel Battegay Emilio Letang 《PloS one》2015,10(4)