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51.
Stuart?G.?Dashper Sze?Wei?Liu Eric?C.?ReynoldsEmail author 《International journal of peptide research and therapeutics》2007,13(4):505-516
Dental caries (tooth decay) and periodontal diseases are the most prevalent bacterial infectious diseases of mankind, together
affecting almost the entire population of the world. Both diseases are caused by oral bacteria that exist as components of
a polymicrobial biofilm, known as dental plaque, on the tooth surface. The control of specific types of bacteria and/or total
numbers of bacteria in dental plaque could lead to prevention or resolution of disease. Antimicrobial peptides isolated from
a wide range of natural sources have been known for over 30 years yet little progress had been made in the therapeutic application
of these peptides. This is due in part to the characteristics, including susceptibility to proteolysis, of the cationic amphipathic
antimicrobial peptides that form the majority of peptides discovered to date. Bovine milk is a readily available source of
a range of bioactive peptides. We have isolated and characterized a novel anionic antimicrobial peptide, Kappacin, from bovine
milk. Antibacterial activity of the peptide is increased when it is complexed with zinc ions. We have demonstrated that a
Kappacin:Zn2+ preparation is able to suppress the growth of oral cariogenic bacteria in a biofilm. The Kappacin:Zn2+ antibacterial complex may have potential as an additive to oral care products and other delivery vehicles for the control
of oral disease. 相似文献
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A negative mode liquid chromatography-selected reaction monitoring mass spectrometry (LC-SRM MS) method was developed to detect low concentrations of the diarrhetic shellfish poisoning (DSP) toxins okadaic acid and dinophysistoxin-1 (DTX-1). Detection relies upon monitoring the transition of negative precursor ions [M - H]- to a common fragment ion of m/z 255. Our limit of detection for okadaic acid with this method is 0.5 pg on column. LC-SRM MS has allowed us to detect persistent, low concentrations of DSP toxins from Singapore shellfish. 相似文献
55.
Pey R Bach J Schieren G Gretz N Hafner M 《In vitro cellular & developmental biology. Animal》1999,35(10):571-579
Summary Autosomal dominant polycystic kidney disease (ADPKD) is one of the most frequent human inherited diseases. The main feature
of the disease is the development of renal cysts, first occurring in the proximal tubules, and with time, dominating all segments
of the nephron, leading to end-stage renal disease in 50% of the patients in their fifth decade of life. A therapy for polycystic
kidney disease (PKD) has not yet been developed. Patients coming to end-stage ADPKD require long-term dialysis and/or transplantation.
A suitable animal model to study ADPKD is the spontaneously mutated Han:SPRD (cy/ +) rat, but a method to cultivate Han:SPRD (cy/ +) derived renal cells which preserves their ability to form cyst-like structures in vitro has previously not been reported.
Based on this well-characterized animal model, we developed a cell culture model of renal cyst formation in vitro. When renal
cells of the Han:SPRD (cy/ +) rat were isolated and cultured under conditions that prevent cell-substratum adhesion, large amounts of cyst-like structures
were formed de novo from Han:SPRD (cy/ +) derived renal cells, but only a few from control rat renal cells. In contrast, when cultivated on plastic as monolayer
cultures, Han:SPRD (cy/ +)-derived and control rat-derived renal cells were indistinguishable and did not form cyst-like structures. Immunohistochemical
characterization of the cyst-like structures suggests tubular epithelial origin of the cyst-forming cells. The amount of cysts
formed from Han:SPRD (cy/ +)-derived renal cells grown in a stationary suspension culture is susceptible to modulation by different conditions. Human
cyst fluid and epidermal growth factor both stimulated the formation of cysts from Han:SPRD (cy/ +)-derived renal cells whereas taxol inhibited cystogenesis. In contrast, neither human cyst fluid nor epidermal growth
factor affected the amount of cysts formed by control rat renal cells. As the culture model reported here allows not only
the distinction of PKD-derived tubular epithelium from its normal counterpart, but also the modulation of cyst formation especially
by Han:SPRD (cy/ +)-derived renal cells, it might be a useful prescreening protocol for potential treatments for PKD and thus reduce the
need for animal experiments.
Both authors contributed equally to the work. 相似文献
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57.
Expression patterns of a novel AtCHX gene family highlight potential roles in osmotic adjustment and K+ homeostasis in pollen development 总被引:4,自引:0,他引:4
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Sze H Padmanaban S Cellier F Honys D Cheng NH Bock KW Conéjéro G Li X Twell D Ward JM Hirschi KD 《Plant physiology》2004,136(1):2532-2547
58.
Teo SK Denny KH Stirling DI Thomas SD Morseth SL Hoberman AM 《Birth defects research. Part B, Developmental and reproductive toxicology》2004,71(1):1-16
BACKGROUND : The present work was performed to determine the effect of thalidomide exposure on reproductive function and early embryonic development. METHODS : Twenty‐five female New Zealand White rabbits were orally gavaged with 0, 10, 50, or 100 mg/kg/day thalidomide 14 days prior to mating through to gestation day 7 for a total of 22 days. Treated females were Caesarean‐sectioned approximately 29 days after the date of attempted mating. Following mating with treated females, male rabbits (25/dose) were gavaged with 0, 30, 150, or 500 mg/kg/day beginning 14 days prior to mating with a group of untreated females (25/dose). Doses were administered through mating until the day before sacrifice for a minimum of 56 days. Untreated females were Caesarean‐sectioned 29 days after the last attempted mating. Comprehensive necropsy and histopathology of the reproductive system were performed. RESULTS : Treated females had reduction in body weight gain during gestation. Mating and pregnancy parameters were unaffected by thalidomide. At 100 m/kg, litter averages for corpora lutea, implantations, litter sizes, does with viable fetuses and live fetuses decreased and the number of early resorptions, does with any resorptions, does with all conceptuses resorbed, and the percent resorbed conceptuses per litter increased. The number of early resorptions, the average number of early resorptions per litter, and the percent resorbed conceptuses per litter increased at 10 and 50 mg/kg. There were no thalidomide‐related external fetal malformations. Mating and fertility in male rabbits were unaffected by thalidomide. There was an increased incidence of flaccid testes at 150 and 500 mg/kg and of bilateral small testes in all treated groups. At 500 mg/kg, there was degeneration of the germinal epithelium of the testicles with an increase in multinucleated giant cells in seminiferous tubule and a loss of round and elongating spermatids. CONCLUSIONS : Thalidomide had no adverse effects on mating and fertility in male and female rabbits dosed up to 500 and 100 mg/kg/day, respectively, for 14 days prior to mating. After 56 day of dosing, histopathologic changes with no associated sperm abnormalities were observed in the testicles. Embryonic development NOAEL for treated females mated to untreated males was <10 mg/kg. Corresponding fertility NOAEL for treated males mated to untreated females was 500 mg/kg. Birth Defects Res B 71:1–16, 2004. © 2004 Wiley‐Liss, Inc. 相似文献
59.
Chromosomal instability (CIN) refers to high rates of chromosomal gains and losses and is a major cause of genomic instability of cells. It is thought that CIN caused by loss of mitotic checkpoint contributes to carcinogenesis. In this study, we evaluated the competence of mitotic checkpoint in hepatoma cells and investigated the cause of mitotic checkpoint defects. We found that 6 (54.5%) of the 11 hepatoma cell lines were defective in mitotic checkpoint control as monitored by mitotic indices and flow-cytometric analysis after treatment with microtubule toxins. Interestingly, all 6 hepatoma cell lines with defective mitotic checkpoint showed significant underexpression of mitotic arrest deficient 2 (MAD2), a key mitotic checkpoint protein. The level of MAD2 underexpression was significantly associated with defective mitotic checkpoint response (p<0.001). In addition, no mutations were found in the coding sequences of MAD2 in all 11 hepatoma cell lines. Our findings suggest that MAD2 deficiency may cause a mitotic checkpoint defect in hepatoma cells. 相似文献
60.
The interaction of Ca(2+)-free calmodulin (apoCaM) with the IQ motif corresponding to the calmodulin-binding domain of neurogranin has been studied by nuclear magnetic resonance (NMR) methods. The NMR spectra of uncomplexed apoCaM and apoCaM in complex with the IQ motif recorded at 750 MHz were studied and the backbone assignments of the protein in both forms were obtained by triple-resonance multidimensional NMR experiments. Chemical shift perturbations were used to map the binding surfaces. Only a single set of resonances was observed throughout the titration, indicating that the binding interaction is under fast exchange. Analysis of chemical shift changes indicates that (a) the main interaction and conformational changes occur in the C-terminal domain of calmodulin and (b) linker-1 (residues 40-44) between EF-1 and EF-2, linker-3 (residues 112-117) between EF-3 and EF-4, and the end of the alpha-helix H (residues 145-148) may be involved in the binding process. The dissociation constant (K(d)), estimated by fitting the chemical shift changes against the IQ peptide concentration, ranged from about 1.2 x 10(-5) to 8.8 x 10(-5) M. This result demonstrates that the interaction falls into the weak binding regime. 相似文献