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排序方式: 共有203条查询结果,搜索用时 15 毫秒
91.
West DS Bursac Z Quimby D Prewitt TE Spatz T Nash C Mays G Eddings K 《Obesity (Silver Spring, Md.)》2006,14(10):1825-1831
Objective: To characterize sugar‐sweetened beverage intake of college students. Research Methods and Procedures: Undergraduates in an urban southern community campus were surveyed anonymously about sugared beverage consumption (soda, fruit drinks, energy drinks, sports drinks, sweet ice tea) in the past month. Results: Two hundred sixty‐five undergraduates responded (66% women, 46% minority, 100% of volunteers solicited). Most students (95%) reported sugared beverage intake in the past month, and 65% reported daily intake. Men were more likely than women to report daily intake (74% vs. 61%, p = 0.035). Soda was the most common sugar‐sweetened beverage. Black undergraduates reported higher sugared beverage intake than whites (p = 0.02), with 91% of blacks reporting sugar‐sweetened fruit drink intake in the past month and 50% reporting daily consumption. Mean estimated caloric intake from combined types of sugar‐sweetened beverages was significantly higher among black students than whites, 796 ± 941 vs. 397 ± 396 kcal/d (p = 0.0003); the primary source of sugar‐sweetened beverage calories among blacks was sugared fruit drinks (556 ± 918 kcal/d). Younger undergraduates reported significantly higher intake than older students (p = 0.025). Discussion: Self‐reported sugar‐sweetened beverage consumption among undergraduates is substantial and likely contributes considerable non‐nutritive calories, which may contribute to weight gain. Black undergraduates may be particularly vulnerable due to higher sugared beverage intake. Obesity prevention interventions targeting reductions in sugar‐sweetened beverages in this population merit consideration. 相似文献
92.
Emma L Hesketh John RP Knight Rosemary HC Wilson James PJ Chong Dawn Coverley 《Cell cycle (Georgetown, Tex.)》2015,14(3):333-341
The minichromosome maintenance complex (MCM2-7) is the putative DNA helicase in
eukaryotes, and essential for DNA replication. By applying serial extractions to mammalian
cells synchronized by release from quiescence, we reveal dynamic changes to the
sub-nuclear compartmentalization of MCM2 as cells pass through late G1 and early S phase,
identifying a brief window when MCM2 becomes transiently attached to the nuclear-matrix.
The data distinguish 3 states that correspond to loose association with chromatin prior to
DNA replication, transient highly stable binding to the nuclear-matrix coincident with
initiation, and a post-initiation phase when MCM2 remains tightly associated with
chromatin but not the nuclear-matrix. The data suggests that functional MCM complex
loading takes place at the nuclear-matrix. 相似文献
93.
Cells adherent on a cyclically stretched substrate with a periodically varying uniaxial strain are known to dynamically reorient nearly perpendicular to the strain direction. We investigate the dynamic reorientation of rat embryonic and human fibroblast cells over a range of stretching frequency from 0.0001 to 20 s−1 and strain amplitude from 1% to 15%. We report quantitative measurements that show that the mean cell orientation changes exponentially with a frequency-dependent characteristic time from 1 to 5 h. At subconfluent cell densities, this characteristic time for reorientation shows two characteristic regimes as a function of frequency. For frequencies below 1 s−1, the characteristic time decreases with a power law as the frequency increases. For frequencies above 1 s−1, it saturates at a constant value. In addition, a minimum threshold frequency is found below that no significant cell reorientation occurs. Our results are consistent for the two different fibroblast types and indicate a saturation of molecular mechanisms of mechanotransduction or response machinery for subconfluent cells within the frequency regime under investigation. For confluent cell layers, we observe similar behaviors of reorientation under cyclic stretch but no saturation in the characteristic time with frequency, suggesting that cell-cell contacts can play an important role in the response machinery of cells under mechanical strain. 相似文献
94.
Palmer MJ McSwain JL Spatz MD Tucker JS Essenberg RC Sauer JR 《Insect biochemistry and molecular biology》1999,29(1):43-51
The salivary glands of ixodid ticks are central to tick feeding and to survival during off-host periods. They produce and secrete a number of molecules critical to maintaining the complex host-vector interface and to maintaining osmotic balance. We have previously shown that a cyclic AMP-dependent protein kinase (cAPK) is involved in the mechanism of salivary gland secretion. We have now cloned cDNAs encoding three isoforms of the catalytic subunit (cAPK-C) of the cAPK from Amblyomma americanum, which are probably produced from alternative RNA processing of a single cAPK-C gene. The cDNAs contain unique N-termini of variable lengths that are linked to a common region containing the alpha A helix, catalytic core, and a C-terminal tail. The common region is highly similar to both insect and vertebrate cAPK-Cs. We have examined mRNA profiles in whole ticks and in isolated salivary glands throughout feeding and find that a single cAPK-C isoform is expressed in the salivary glands of both unfed and feeding females. 相似文献
95.
Steinmetz NF Bock E Richter RP Spatz JP Lomonossoff GP Evans DJ 《Biomacromolecules》2008,9(2):456-462
The development of multilayered thin film assemblies containing (bio)molecules is driven by the need to miniaturize sensors, reactors, and biochips. Viral nanoparticles (VNPs) have become popular nanobuilding blocks for material fabrication, and our research has focused on the well-characterized plant virus Cowpea mosaic virus (CPMV). In a previous study, we have reported the construction of multilayer VNP assemblies. Here we extend these studies by providing further details on the formation and properties of arrays that are made by the alternating deposition of biotinylated CPMV particles and streptavidin molecules. Array formation was followed in real time by a quartz crystal microbalance with dissipation monitoring. Our data provide indications that multiple interactions between biotin and streptavidin not only promote the assembly of a multilayered structure but also generate cross-links within each layer of CPMV particles. The degree of intralayer and interlayer cross-linking and hence the mechanical properties and order of the array can be modulated by the grafting density and spacer length of the biotin moieties on the CPMV particles. 相似文献
96.
A microtransfer technique for micropattern fabrication using a dithiol macromolecular linker is suggested by transferring a conventionally photolithography-prepared gold microarray on a hard inorganic substrate to a polymeric substrate. The linker was synthesized by end-capping a poly(ethylene glycol) (PEG) chain by the thiol groups. The efficiency of this technique is demonstrated by the transfer of gold microdots from glass to a cell-adhesion-resistant PEG hydrogel, which was formed by polymerizing PEG diacrylate macromers. The stability and biocompatibility of the resulting polymeric-inorganic hybrid material and cell-adhesion contrast of the patterned surface is confirmed by preliminary cell experiments. 相似文献
97.
Silvia Vincent‐Naulleau Catherine Le Chalony Jean‐Jacques Leplat Stphan Bouet Christiane Bailly Alain Spatz Philippe Vielh Marie‐Franoise Avril Yves Tricaud Joseph Gruand Vratislav Horak Grard Frelat Claudine Geffrotin 《Pigment cell & melanoma research》2004,17(1):24-35
Spontaneous animal tumors appear to be highly suitable models to study human oncology and cancer therapy. The aim of this study was to characterize the clinical and histological features of hereditary melanocytic lesions found in the French herd of melanoblastoma‐bearing Libechov minipigs (MeLiM) and their Duroc crossbreeds. Clinically, we discriminated between three types of melanocytic skin lesions, which offer a lesion continuum from lentigo to metastatic melanomas. More than 70% of these lesions appear on piglets before they are 3 months old and preferentially on homogeneous black coat piglets. The incidence of melanoma reaches 50% in MeLiM. Most of the highly invasive melanomas regressed spontaneously in the first year of the piglet's life and the regression was followed by hair, skin and iris depigmentation. A histopathological study was conducted according to the human melanoma classification. Except for lentigo maligna, we observed the three main types of human melanoma in swine [superficial spreading melanoma (SSM), nodular or unclassified melanoma] with an excess of SSM (59–67%). The histological events leading to total spontaneous regression are chronologically described. The genetic predisposition, the high incidence of melanoma, the clinical and histopathological features similar to the human disease and the high rate of spontaneous regression offer an opportunity to use this model for studying genetic events controlling melanoma development and regression and the biological mechanisms involved in oncogenesis and anti‐cancerous self‐defense. 相似文献
98.
Kaye AM Spatz M Waisman A Sasson S Tamir S Vaya J Somjen D 《The Journal of steroid biochemistry and molecular biology》2001,76(1-5):85-93
The phenomenon of mutual annihilation of action between 17β estradiol (E2) and a selective estrogen receptor modulator (SERM), previously described in prepubertal rat diaphysis, epiphysis and uterus, has been investigated in ROS 17/2.8 rat osteoblastic cells and in transiently co-transfected cells in culture. In ROS 17/2.8 cells, the estrogen-induced marker enzyme creatine kinase B (CKB) was stimulated by raloxifene, tamoxifen and tamoxifen methiodide to a specific activity equal to or greater than that induced by 10 nM E2. However, when a fully inhibitory dose of any of these SERMS was given simultaneously with E2, no stimulation of CK activity resulted. Therefore, SERMS can be full agonists when acting alone, but complete antagonists to a super-physiological dose of estrogen. It is expected that excess tamoxifen would prevent the action of a SERM, but that the agonist activity of a SERM is abolished by 1000-fold less estrogen is a phenomenon without obvious explanation by classical pharmacology of competitive inhibition. To probe the mechanism of this interaction further, a ckb-CAT reporter plasmid, plus the human receptor expression plasmid, HEO, was transfected transiently into several cell types. In MCF-7 cells, a 1:10 ratio of E2 to tamoxifen produced mutual annihilation, but the same ratio in ROS 17/2.8 or HeLa cells led to synergistic stimulation. In HeLa cells, co-transfected with the more efficient wild-type estrogen receptor plasmid, HEGO, synergy was demonstrated only at sub-saturation levels of HEGO. We speculate that, in the presence of estradiol and a SERM, not only active homodimers would be formed, but also hetero-dimers of estrogen-liganded and tamoxifen-liganded receptor monomers, depending on the molar ratio of their ligands and their relative affinities. The resulting hetero-dimer conformation would change the specific receptor surface for interactions with the growing number of co-activators and co-repressors, structural changes which could help to explain the mutual annihilation and synergy phenomena and their cell selectivity. 相似文献
99.
ET-1- and NO-mediated signal transduction pathway in human brain capillary endothelial cells 总被引:6,自引:0,他引:6
Chen Y McCarron RM Golech S Bembry J Ford B Lenz FA Azzam N Spatz M 《American journal of physiology. Cell physiology》2003,284(2):C243-C249
Previous studies have demonstratedthat functional interaction between endothelin (ET)-1 and nitric oxide(NO) involves changes in Ca2+ mobilization and cytoskeletonin human brain microvascular endothelial cells. The focus of thisinvestigation was to examine the possible existence of analogousinterplay between these vasoactive substances and elucidate theirsignal transduction pathways in human brain capillary endothelialcells. The results indicate that ET-1-stimulated Ca2+mobilization in these cells is dose-dependently inhibited by NOR-1 (anNO donor). This inhibition was prevented by ODQ (an inhibitor ofguanylyl cyclase) or Rp-8-CPT-cGMPS (an inhibitor of proteinkinase G). Treatment of endothelial cells with 8-bromo-cGMP reducedET-1-induced Ca2+ mobilization in a manner similar to thatobserved with NOR-1 treatment. In addition, NOR-1 or cGMP reducedCa2+ mobilization induced by mastoparan (an activator of Gprotein), inositol 1,4,5-trisphosphate, or thapsigargin (an inhibitorof Ca2+-ATPase). Interestingly, alterations in endothelialcytoskeleton (actin and vimentin) were associated with these effects.The data indicate for the first time that the cGMP-dependent proteinkinase colocalizes with actin. These changes were accompanied byaltered levels of phosphorylated vasodilator-stimulated phosphoprotein, which were elevated in endothelial cells incubated with NOR-1 andsignificantly reduced by ODQ or Rp-8-CPT-cGMPS. The findings indicate a potential mechanism by which the functionalinterrelationship between ET-1 and NO plays a role in regulatingcapillary tone, microcirculation, and blood-brain barrier function. 相似文献
100.
Clinical and histopathological characterization of cutaneous melanomas in the melanoblastoma-bearing Libechov minipig model 总被引:3,自引:0,他引:3
Vincent-Naulleau S Le Chalony C Leplat JJ Bouet S Bailly C Spatz A Vielh P Avril MF Tricaud Y Gruand J Horak V Frelat G Geffrotin C 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》2004,17(1):24-35
Spontaneous animal tumors appear to be highly suitable models to study human oncology and cancer therapy. The aim of this study was to characterize the clinical and histological features of hereditary melanocytic lesions found in the French herd of melanoblastoma-bearing Libechov minipigs (MeLiM) and their Duroc crossbreeds. Clinically, we discriminated between three types of melanocytic skin lesions, which offer a lesion continuum from lentigo to metastatic melanomas. More than 70% of these lesions appear on piglets before they are 3 months old and preferentially on homogeneous black coat piglets. The incidence of melanoma reaches 50% in MeLiM. Most of the highly invasive melanomas regressed spontaneously in the first year of the piglet's life and the regression was followed by hair, skin and iris depigmentation. A histopathological study was conducted according to the human melanoma classification. Except for lentigo maligna, we observed the three main types of human melanoma in swine [superficial spreading melanoma (SSM), nodular or unclassified melanoma] with an excess of SSM (59-67%). The histological events leading to total spontaneous regression are chronologically described. The genetic predisposition, the high incidence of melanoma, the clinical and histopathological features similar to the human disease and the high rate of spontaneous regression offer an opportunity to use this model for studying genetic events controlling melanoma development and regression and the biological mechanisms involved in oncogenesis and anti-cancerous self-defense. 相似文献