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排序方式: 共有902条查询结果,搜索用时 16 毫秒
1.
JJ Korelitz ; AE Williams ; MP Busch ; TF Zuck ; HE Ownby ; LJ Matijas ; DJ Wright 《Transfusion》1994,34(10):870-876
BACKGROUND: Most blood centers utilize a confidential unit exclusion (CUE) process, intended to reduce the risk of transfusion-associated infectious diseases by allowing high-risk donors confidentially to exclude their blood from use for transfusion. The effectiveness of this method remains controversial. STUDY DESIGN AND METHODS: Confirmatory or supplemental test results for antibodies to human immunodeficiency virus, human T-lymphotropic virus type I, and hepatitis C virus, as well as hepatitis B surface antigen and syphilis and screening test results for antibodies to hepatitis B core (antigen) and alanine aminotransferase levels were obtained for approximately 1.8 million units donated during 1991 and 1992 at five blood centers within the United States. The prevalences of these infectious disease markers in units that the donors confidentially excluded (CUE+) and units that the donors did not exclude (CUE-) were calculated and examined within demographic subgroups. RESULTS: Units that were CUE+ were 8 to 41 times more likely to be seropositive for antibodies to human immunodeficiency virus and hepatitis C virus, hepatitis B surface antigen, and syphilis and three to four times more likely to react for antibody to hepatitis B core (antigen) or to have elevated alanine aminotransferase levels than units that were CUE- (p < 0.001). The positive predictive value of CUE (the percentage of CUE+ units that were confirmed seropositive for any marker) was 3.5 percent, and the sensitivity of CUE (the percentage of confirmed-seropositive units that were CUE+) was 2.3 percent. CONCLUSION: The current CUE process has low sensitivity and apparently low positive predictive value, and in many cases, it appeared that donors misunderstood it. Yet, CUE was not a “random process,” as CUE+ units were more likely to be seropositive for any infectious disease marker than CUE- units. This suggests that efforts to improve the CUE system may be warranted. As risk factors for transfusion-transmitted infection become more difficult to identify by history-based screening, however, such efforts may have limited effect. 相似文献
2.
Total radical trapping antioxidant potential (TRAP) and exercise 总被引:1,自引:0,他引:1
Sharpe PC; Duly EB; MacAuley D; McCrum EE; Mulholland C; Stott G; Boreham CA; Kennedy G; Evans AE; Trinick TR 《QJM : monthly journal of the Association of Physicians》1996,89(3):223-228
The relationship between physical activity, physical fitness and total
radical trapping antioxidant potential (TRAP) was examined in the Northern
Ireland Health and Activity Survey. This was a cross-sectional population
study (n = 1600) using a two-stage probability sample of the population.
TRAP was calculated using the sum of the individual serum antioxidant
concentrations (urate, protein thiols, ascorbate, alpha tocopherol and
bilirubin) multiplied by their respective stoichiometric values. Physical
fitness was determined by estimation of VO2max by extrapolation from
submaximal oxygen uptake, and physical activity was recorded by
computer-assisted interview. Mean serum TRAP concentrations were
significantly higher in males (653 +/- 8.2 mumol/l, mean +/- SEM) compared
to females (564 +/- 8.0 mumol/l) (p < 0.0001). Both male and female
smokers had significantly lower TRAP values than non-smokers (males p <
0.0001, females p = 0.02). In females, there was a positive relationship of
TRAP with age (p < 0.001) and body mass index (p < 0.001) but a
negative relationship with physical fitness (p < 0.05). The known
beneficial effects of exercise and activity do not appear to be directly
mediated through increased antioxidant status.
相似文献
3.
Fitzmaurice J Glennon M Duffy G Sheridan JJ Carroll C Maher M 《Molecular and cellular probes》2004,18(2):123-132
Real-time PCR assays, based on hybridisation probes and LightCycler technology, were developed for VT 1 and VT 2 genes and applied to the detection and quantitation of DNA and mRNA of Escherichia coli O157:H7. The qualitative consensus PCR assay for the detection of VT 1 and/or VT 2 genes had a detection limit of 100 fg of E. coli O157:H7 genomic DNA and did not detect DNA from 13 non-VTEC isolates. When E. coli O157:H7 was inoculated into minced beef, enriched and recovered by immunomagnetic separation, the real-time consensus PCR assay had a detection limit of log(10)3.5 ml(-1) E. coli O157:H7 cells. Nineteen E. coli O157:H7 isolates, derived from food, bovine samples and human faeces, were analysed and compared for mRNA expression of three genes, VT 1, VT 2 and gapA (housekeeping gene), using quantitative real-time PCR assays. While there was no statistically significant difference for the expression of the VT 1 (p=0.134) or VT 2 (p=0.52) mRNA in the E. coli O157:H7 isolates from food, bovine and human sources, three clinical isolates did show lower expression of VT 2 compared to other isolates in the study. The study indicates that the consensus qualitative real-time PCR assay for VT 1 and VT 2 is rapid and sensitive and that the quantitative assays reported here have the potential to be used as an alternative method to more conventional methods for studying VT 1 and VT 2 virulence gene expression in E. coli O157:H7 with potential application in other pathogenic E. coli species. 相似文献
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