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31.
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9-(2-膦酰甲氧乙基)腺嘌呤及其位置异构体3-(2-膦酰甲氧乙基)腺嘌呤的合成和抗病毒活性研究 总被引:1,自引:0,他引:1
Phosphonylmethoxyethyl)adenine (1),PMEA,an acyclic nucleotide withbroad-spectrum antiviral activity was synthesized with some modifications of Holy's procedure.Simutaneously,an N-3 regioisomer(2)of PMEA and a by-preduct, formaldehyde di-[2-(9-adenyl)ethyl] acetal(7)were seperated by silica gel chromatography in the ratio of 50:10:1.Compound(2)and(7) are new compounds that we have not yet found in literatures. The structure of them weredetermined with 1HNMR,2DNMR, MS and Spot test.Antiviral test showed that N-3 isomer(2)completely lost activity against both HIV-1 and HSV-1 in vitro. It seems that regiospecificity of theacyclic nucleotide structure is important for antiviral activity. 相似文献
34.
Hoos A. D'Incan C. Gissmann L. Altmann A. Momburg F. Nindl I. Osen W. Schönning BH. Jochmus I. 《Archives of virology》1996,141(3-4):449-458
Archives of Virology - The low expression of major histocompatibility complex (MHC) class I antigens on human papillomavirus (HPV)-infected cervical carcinoma cells may be responsible for an... 相似文献
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36.
Quantitative liver function in patients with rheumatoid arthritis treated with low-dose methotrexate: a longitudinal study 总被引:4,自引:0,他引:4
Beyeler C; Reichen J; Thomann SR; Lauterburg BH; Gerber NJ 《Rheumatology (Oxford, England)》1997,36(3):338-344
The objectives were to determine quantitative liver function prospectively
in patients with rheumatoid arthritis (RA) treated with low-dose
methotrexate (MTX), to search for risk factors for a loss of quantitative
liver function and to assess the relationship between quantitative liver
function and histological staging. A total of 117 patients with RA (ACR
criteria, 85 women, mean age 59 yr) had measurements of galactose
elimination capacity (GEC), aminopyrine breath test (ABT) and liver enzymes
[aspartate amino transferase (AST), alanine amino transferase (ALT),
alkaline phosphatase (AP), 7-glutamyl transferase (GGT), bile acids,
bilirubin, albumin] before treatment with weekly i.m. MTX injections and
every year thereafter. In 16 patients, liver biopsies were performed.
Before the introduction of MTX, mean GEC was 6.6 mg/min/kg [5th to 95th
percentile (5-95 PC) 5.1- 8.5; reference range 6.0-9.1] and mean ABT was
0.80% kg/mmol (5-95 PC 0.42-1.30: reference range 0.6-1.0). During
treatment with MTX [mean weekly dose 11.8 mg (5-95 PC 5.4-20.2), mean
observation period 3.8 yr (5-95 PC 0.4-6.9)], significant declines of GEC
(-0.12 mg/min/kg per year. t = 3.30, P < 0.002) and ABT (-0.06% kg/mmol
per year, t = 4.81, P < 0.001) were observed. Negative correlations were
found between the annual change in GEC and GEC at baseline (Rs = -0.40, P
< 0.0001), and the annual change in ABT and ABT at baseline (Rs = -0.43,
P < 0.0001). No correlations were found between the annual change in GEC
or ABT and weekly MTX dose, age or percentage of increased liver enzymes,
and no effect of a history of alcohol consumption > 30 g/week became
evident. Two patients with Roenigk grade III had impaired quantitative
liver function, while 14 patients with Roenigk grades I and II exhibited a
high variability of GEC and ABT from normal to abnormal values. The
continuous declines in GEC and ABT observed deserve attention in patients
with prolonged treatment. Patients with a low GEC or ABT at baseline seem
not to be at increased risk for a further loss of quantitative liver
function. An impaired GEC or ABT does not necessarily concur with hepatic
fibrosis on histological examination.
相似文献
37.
Different methods were used to assay diphtheria toxin sensitivity of fibroblast and heart cell cultures from chicken embryos of various ages. As defined by inhibition of protein synthesis, fibroblasts from 18-day and younger embryos respond more rapidly to toxin than fibroblasts from older embryos. The response of heart cells cultures is independent of the age of the embryos and is similar to the response of fibroblasts from 18-day embryos. Since the EF-2 content is 10-fold less in fibroblasts from 21-day-old embryos, the different responses of protein synthesis to intoxication appear to reside at the membrane level. Cytotoxicity assays in cell culture and in vivo toxin sensitivity assays show that cells from both young and old embryos, as well as whole embryos, are equally sensitive to toxin. Thus, short-term (5-h) measurements of inhibition of protein synthesis are insufficient for determining the relative sensitivity of cells to intoxication as defined by cell death. 相似文献
38.
A highly sensitive and specific radioimmunoassay has been developed for Pseudomonas aeruginosa alkaline protease. Production of alkaline protease was found to be strain variable and medium dependent. 相似文献
39.
Pseudomonas aeruginosa exoenzyme S: an adenosine diphosphate ribosyltransferase distinct from toxin A. 总被引:37,自引:3,他引:34
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B H Iglewski J Sadoff M J Bjorn E S Maxwell 《Proceedings of the National Academy of Sciences of the United States of America》1978,75(7):3211-3215
Pseudomonas aeruginosa exoenzyme S is an adenosine diphosphate ribosyltransferase distinct from Pseudomonas toxin A. Exoenzyme S catalyzes the transfer of radioactivity from all portions of radiolabeled NAD+ except nicotinamide. Digestion of the radiolabeled product(s) formed in the presence of [adenine-14C]NAD+ and exoenzyme S with snake venom phosphodiesterase yields only AMP, suggesting that ADP-ribose is present as monomers and not as poly(ADP-ribose). Exoenzyme S does not catalyze the transfer of ADP-ribose from NAD+ to elongation factor 2, as do toxin A and diphtheria toxin, but to one or more other proteins present in crude extracts of wheat germ or rabbit reticulocytes and in partially purified preparations of elongation factor I. The ADP-ribosyltransferase activity of exoenzyme S is distinct from toxin A by several tests: it is not neutralized by toxin A antibody, it is destroyed rather than potentiated by pretreatment with urea, and it is more heat stable. These latter observations and the substrate specificity suggest that exoenzyme S is different from any previously described prokaryotic ADP-ribosyltransferase. 相似文献
40.
Effect of formalin toxoiding on Pseudomonas aeruginosa toxin A: biological, chemical, and immunochemical studies. 总被引:6,自引:4,他引:2
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We investigated the effect of Formalin toxoiding on the biological, chemical, and immunological activities of Pseudomonas aeruginosa toxin A. Formalin treatment alone resulted in a 1,000-fold decrease in toxin-induced cell cytotoxicity and altered the antigenicity of the toxin A molecule without adversely affecting enzymatic activity. Competitive blocking experiments indicated that Formalin-mediated detoxification proceeded via alterations in a region of the toxin molecule other than the active site of the enzyme. The addition of lysine to Formalin-toxin mixtures not only increased the rate and extent of detoxification and antigenic alteration, but also completely destroyed enzymatic activity. The immunogenicities of different toxoids varied substantially. Upon dialysis and storage, Formalin-derived toxoids underwent partial toxic reversion, whereas a Formalin-lysine-derived toxoid did not. The sodium dodecyl sulfate-polyacrylamide gel patterns of Formalin- and Formalin-lysine-treated toxins indicated that these treatments caused the formation of a heterogenous group of high-molecular-weight species and produced substantial changes in the electrophoretic mobility of toxin A. 相似文献