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Gene conversion is a likely cause of mutation in PKD1 总被引:3,自引:0,他引:3
Watnick TJ; Gandolph MA; Weber H; Neumann HP; Germino GG 《Human molecular genetics》1998,7(8):1239-1243
Approximately 70% of the gene responsible for the most common form of
autosomal dominant polycystic kidney disease ( PKD1 ) is replicated in
several highly homologous copies located more proximally on chromosome 16.
We recently have described a novel technique for mutation detection in the
duplicated region of PKD1 that circumvents the difficulties posed by these
homologs. We have used this method to identify two patients with a nearly
identical cluster of base pair substitutions in exon 23. Since pseudogenes
are known to be reservoirs for mutation via gene conversion events for a
number of other diseases, we decided to test whether these sequence
differences in PKD1 could have arisen as a result of this mechanism. Using
changes in restriction digest patterns, we were able to show that these
sequence substitutions are also present in N23HA, a rodent-human somatic
cell hybrid that contains only the PKD1 homologs. Moreover, these changes
were also detected in total DNA from several affected and unaffected
individuals that did not harbor this mutation in their PKD1 gene copy. This
is the first example of gene conversion in PKD1 , and our findings
highlight the importance of using gene-specific reagents in defining PKD1
mutations.
相似文献
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P. H. Joubert C. P. Venter H. F. Joubert I. Hillebrand 《European journal of clinical pharmacology》1985,28(6):705-708
Summary BAY m1099 (a 1-deoxynojirimycin derivative) is a glucose analogue which is an -glucosidase inhibitor. Its effects on post-prandial blood glucose and insulin levels was compared with a placebo in 12 healthy male volunteers (6 Blacks and 6 Whites). It produced a similar, significant depression of post-prandial blood glucose and insulin leveles when the groups were assessed separately and when the data were pooled. Although blood insulin levels in Whites were higher than in Blacks, as previously reported, the difference was not statistically significant and did not appear to influence the response to the drug. BAY 1099 produced no objective or subjective untoward effects and appears to warrant further investigation as an adjuvant to dietary control of diabetes mellitus. 相似文献
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The activity of beta-glucuronidase in methyl-N-nitrosourea-induced rat mammary tumors regressing after ovariectomy was studied. beta-Glucuronidase, acid phosphatase, and beta-hexosaminidase were similarly increased in the lysosome-rich fraction of regressing compared to growing tumors, whereas in the soluble fraction, a 5-fold increase in the activity of beta-glucuronidase midway regression was not paralleled by an increase in the specific activity of the other two enzymes. Results of sedimentability studies indicated an equal stability of the lysosomes at the two tumor conditions. The elevated beta-glucuronidase activity in the soluble fraction was completely precipitable by rabbit monospecific antisera against beta-glucuronidase from other species. The activity in the soluble and in the lysosome-rich fraction showed a similar pH dependence and electrophoretic mobility of immunoreactive subunits, and only minor differences in affinity towards concanavalin A:Sepharose. Thus, the increased "soluble" beta-glucuronidase activity is neither tumor nor cytosol specific. Cell death during tumor regression is believed to occur according to a controlled sequence of event, called apoptosis. Dying cells become apoptotic bodies which are further degraded during phagocytosis by neighboring tumor cells. We discuss that breakage of these bodies during homogenization of the tumor is the cause for the observed increase in soluble beta-glucuronidase activity, while the lysosomes of the ingesting tumor cells remain intact. Physiologically, the enhanced intratumoral availability of beta-glucuronidase and other lysosomal enzymes might facilitate the hydrolysis of conjugates of a variety of xenobiotics and, possibly, also of steroid hormones. 相似文献
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BACKGROUND & AIMS: Shwachman syndrome is an inherited condition with multisystemic abnormalities, including exocrine pancreatic dysfunction. The aim of this study was to evaluate the occurrence and progression of features in a large cohort of patients. METHODS: Clinical records of 25 patients with Shwachman syndrome were reviewed. RESULTS: Mean birth weight (2.92 +/- 0.51 kg) was at the 25th percentile. However, by 6 months of age, mean heights and weights were less than the 5th percentile. After 6 months of age, growth velocity was normal. Severe fat maldigestion due to pancreatic insufficiency was present in early life (fecal fat, 26% +/- 17% of fat intake; age, < 2 years). Serial assessment of exocrine pancreatic function showed persistent deficits of enzyme secretion, but 45% of patients showed moderate age-related improvements leading to pancreatic sufficiency. Neutropenia was the most common hematologic abnormality (88%), but leukopenia, thrombocytopenia, and anemia were also frequently encountered. Patients with hypoplasia of all three bone marrow cellular lines (n = 11) had the worst prognosis; 5 patients died, 2 of sepsis and 3 of acute myelogenous leukemia. Other findings included hepatomegaly and/or abnormal liver function test results and skeletal abnormalities. CONCLUSIONS: A wide and varied spectrum of phenotypic abnormalities among patients with Shwachman syndrome is described. Pancreatic acinar dysfunction is an invariable abnormality. Patients with severe bone marrow involvement may have a guarded prognosis. (Gastroenterology 1996 Dec;111(6):1593-602) 相似文献
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Such J Hillebrand DJ Guarner C Berk L Zapater P Westengard J Peralta C Soriano G Pappas J Francés R Muñoz C Runyon BA 《European journal of gastroenterology & hepatology》2004,16(6):571-577
BACKGROUND/AIMS: Cirrhotic patients with spontaneous bacterial peritonitis show a marked activation of the cytokine cascade, and cytokines induce the synthesis of nitric oxide in vitro. Our aim was to assess whether patients with ascitic fluid infection show increased levels of nitric oxide, and whether this is related to the development of renal impairment. METHODS: Retrospective analysis of prospectively collected specimens from 168 patients with cirrhosis and presence of sterile or infected ascitic fluid. Routine biochemical data together with nitric oxide metabolites, tumour necrosis factor and interleukin-6 were measured. Univariate and multivariate analyses were performed to identify factors related to the development of renal impairment. RESULTS: Patients with infected ascites showed increased serum and ascitic-fluid levels of nitric oxide metabolites and cytokines compared with patients with sterile ascites. A significant direct correlation was observed between serum and ascitic fluid nitric oxide metabolite levels. Multivariate analysis identified ascitic-fluid nitric oxide metabolites as an independent predictor of renal impairment. CONCLUSIONS: The increased serum and ascitic fluid nitric oxide found in patients with infected ascites might induce a deterioration of the increased peripheral vasodilation found in this setting, leading to the development of renal impairment in a series of patients with spontaneous bacterial peritonitis. 相似文献