全文获取类型
收费全文 | 1148篇 |
免费 | 43篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 35篇 |
妇产科学 | 6篇 |
基础医学 | 89篇 |
口腔科学 | 36篇 |
临床医学 | 120篇 |
内科学 | 445篇 |
皮肤病学 | 11篇 |
神经病学 | 23篇 |
特种医学 | 225篇 |
外科学 | 41篇 |
综合类 | 36篇 |
预防医学 | 36篇 |
眼科学 | 18篇 |
药学 | 26篇 |
肿瘤学 | 46篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 14篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 22篇 |
2013年 | 22篇 |
2012年 | 39篇 |
2011年 | 44篇 |
2010年 | 41篇 |
2009年 | 40篇 |
2008年 | 48篇 |
2007年 | 54篇 |
2006年 | 44篇 |
2005年 | 46篇 |
2004年 | 37篇 |
2003年 | 31篇 |
2002年 | 39篇 |
2001年 | 34篇 |
2000年 | 15篇 |
1999年 | 27篇 |
1998年 | 46篇 |
1997年 | 56篇 |
1996年 | 51篇 |
1995年 | 49篇 |
1994年 | 48篇 |
1993年 | 30篇 |
1992年 | 15篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 21篇 |
1988年 | 31篇 |
1987年 | 14篇 |
1986年 | 29篇 |
1985年 | 27篇 |
1984年 | 12篇 |
1983年 | 18篇 |
1982年 | 18篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 10篇 |
1976年 | 15篇 |
1975年 | 4篇 |
1969年 | 1篇 |
排序方式: 共有1197条查询结果,搜索用时 17 毫秒
121.
BACKGROUND: Polyethylene glycol (PEG) has been shown to potentiate antigen-antibody reactions. STUDY DESIGN AND METHODS: To investigate the utility of PEG in pretransfusion testing, a blinded comparison study of PEG and a low-ionic-strength additive solution (LISS) was conducted. A total of 500 patient samples were tested in parallel with reagent antibody-detection cells using blind-coded PEG and LISS potentiators. RESULTS: In 34 (34%) of 100 samples with known antibodies in the Rh, Kell, Duffy, Kidd, and MNS systems, PEG antiglobulin reactions were stronger (total score, 382) than LISS antiglobulin reactions (total score, 216), and in 66 cases (66%), they were equal to those of LISS. Of 400 samples without detectable antibodies, 384 were negative with PEG and LISS, and 16 were positive in PEG tests and negative in LISS. Seven of the 16 were clinically important antibodies (D, 1; E, 3; Fya, 1; Jka; 1; Jkb, 1), and four were clinically benign antibodies (Le(a), 2; McCc, 1; Sda, 1). Five of the 16 demonstrated inconclusive PEG reactions, for a false-positive rate of 5 in 400 (1.3%). Of the 500 samples, none was negative in PEG tests and positive in LISS (0% false-negative rate). CONCLUSION: Although PEG demonstrates a relatively high false-positive rate, PEG is more sensitive than LISS in detecting clinically significant antibodies. 相似文献
122.
A Lorentz ; A Jendrissek ; KU Eckardt ; M Schipplick ; PM Osswald ; A Kurtz 《Transfusion》1991,31(7):650-654
The variations in plasma erythropoietin (EPO) concentration during preoperative deposit of autologous blood were studied in 12 patients (8 men, 4 women). Four donations were scheduled at weekly intervals. A predonation hemoglobin concentration of 11 g per dL (110 g/L) was required. Hemoglobin concentration decreased from 14.3 +/- 1.1 g per dL (143 +/- 11 g/L) (mean +/- SD) before the first donation to 11.7 +/- 0.7 g per dL (117 +/- 7 g/L) on Day 22 (p less than or equal to 0.0001). Reticulocyte counts increased from a median of 31,800 (range, 4900-95,000) per microL (median, 32 x 10(9)/L [range, 5-95 x 10(9)/L]) to 93,800 (16,800-194,900) per microL (median, 94 x 10(9)/L [range, 17-195 x 10(9)/L]) on Day 28 (p less than or equal to 0.01). Plasma EPO concentration was 17.8 +/- 5.1 mU per mL prior to the first donation and displayed a small and transient peak after each donation. A sustained elevation followed each peak. Although plasma EPO concentration differed significantly from the baseline value after the first donation, only the peak concentrations after the second (35.5 +/- 15.5 mU/mL), third (38.0 +/- 14.5 mU/mL), and fourth (36.1 +/- 11.0 mU/mL) donations exceeded the normal range. The moderate, biphasic increase in plasma EPO concentration and the moderate increase in erythropoiesis suggest two strategies in autologous blood donation that should be investigated with respect to efficiency and safety: 1) more aggressive donation schemes, which reduce donation intervals and/or the minimum hemoglobin concentration and 2) the administration of recombinant human EPO. 相似文献
123.
Transmission of hepatitis G virus in patients with angioedema treated with steam-heated plasma concentrates of C1 inhibitor 总被引:2,自引:0,他引:2
F De Filippi; R Castelli ; M Cicardi ; R Soffredini ; MG Rumi ; E Silini ; PM Mannucci ; M Colombo 《Transfusion》1998,38(3):307-311
BACKGROUND: Hepatitis G virus (HGV) is a blood-borne flavivirus that may cause acute and chronic transfusion-transmitted infections. Patients with complement component 1 (C1) inhibitor (C1-INH) deficiency may acquire blood-borne infections through infusion of plasma concentrates. STUDY DESIGN AND METHODS: Serum samples from 84 patients with C1-INH deficiency (19 who received unmodified C1-INH concentrates, 23 who received steam-heated concentrates, and 42 untreated patients) were tested for HGV RNA and hepatitis C virus (HCV) RNA by a nested polymerase chain reaction (PCR). The samples were also tested for antibodies to the E2 envelope protein of HGV (anti-HGV) and to HCV with enzyme-linked immunosorbent assays. RESULTS: Nine (11%) patients had serum HGV RNA; that is, 7 (17%) of 42 patients previously treated with C1-INH concentrates and 2 of 42 previously untreated patients. HGV RNA was as common in the 19 patients treated with unmodified concentrates as in the 23 given steam-heated concentrates (16 vs. 17%, p = 0.60). Anti-HGV was more common among the recipients of unmodified concentrates than among those given steam-heated concentrates (26 vs. 0%, p = 0.014). HCV RNA was more frequently detected in treated patients than in untreated patients (33 vs. 7%, p = 0.005) and in the 19 recipients of unmodified concentrates than in the 23 treated with steam-heated concentrates (58 vs. 16%, p = 0.003). Only one HGV RNA- seropositive patient had elevated serum aminotransferase activity, compared to 11 with HCV RNA. CONCLUSION: HGV was transmitted by both unmodified and steam-heated concentrates, but it caused persistent viremia in a minority of the cases and was rarely associated with liver disease. 相似文献
124.
BACKGROUND: Individuals with epilepsy or seizure disorders are restricted from donating blood because of concern that they are prone to adverse donor reactions such as syncope and convulsions. A study evaluating whether that concern is warranted is reported. STUDY DESIGN AND METHODS: During a 2-year period beginning in 1987, blood donors in Maryland with a history of seizures were actively recruited by the American Red Cross. Adverse donor reactions were classified as "slight", indicating dizziness and nausea without loss of consciousness; "moderate," denoting syncope; and "severe," indicating convulsive syncope. RESULTS: There were 329,143 satisfactory blood donations; 613 individuals reporting a history of seizures donated blood a total of 723 times. Among donors with seizures, 186 (35.7%) were taking antiepileptic medication, and 61 (8.4%) had had one or more seizures in the preceding year. Individuals with seizures had a low incidence of adverse reactions (3.34%). Although this incidence was slightly higher than that in the entire population (2.24%), the difference was not significant. In particular, the risk of syncope with or without convulsive activity was low for people with seizures (0.21%) and not significantly greater than that in other donors (0.28%). CONCLUSION: Individuals with seizures or epilepsy are not at greater risk for adverse reactions after blood donation, and major restrictions on their participation as blood donors are not warranted. 相似文献
125.
P M Ridker 《Annals of internal medicine》1999,130(11):933-937
Myocardial infarction often occurs among persons without traditional risk factors, and it has been hypothesized that assessment of "novel" markers may help identify persons who are prone to premature atherothrombosis. However, when considering the clinical utility of screening for any new marker for cardiovascular disease, physicians should consider whether there is a standardized and reproducible assay for the marker of interest; whether there is a consistent series of prospective epidemiologic studies indicating that baseline elevations of the novel marker predict future risk; and whether assessment of the novel marker adds to the predictive value of other plasma-based risk factors, specifically, the ratio of total cholesterol to high-density lipoprotein cholesterol. In this article, these criteria are used to evaluate five promising markers of cardiovascular risk: lipoprotein(a), total plasma homocysteine, fibrinolytic capacity, fibrinogen, and high-sensitivity C-reactive protein. Background is also provided to assist physicians in deciding whether one or more of these novel markers deserve clinical consideration in general outpatient settings. 相似文献
126.
Little DM; Farrell JG; Cunningham PM; Hickey DP 《QJM : monthly journal of the Association of Physicians》1997,90(10):641-642
Systemic donor infection is regarded as being an absolute contraindication
to cadaveric organ donation for transplantation. This is largely due to
fear of transmitting pathogenic organisms to the immunosuppressed
recipient. However, due to the current shortage of organs available for
transplantation, clinicians are faced with the option of using organs from
'non-ideal' donors, such as those patients with documented evidence of
infection. We report the successful outcome of six orthotopic liver
transplants, 11 renal transplants, one combined heart lung transplant and
one simultaneous kidney and pancreas transplant with organs from eight
donors in whom bacterial meningitis (n = 7) and acute bacterial
epiglottitis (n = 1) were the antecedent causes of death.
相似文献
127.
128.
Jean‐Philippe Brandel MD Craig A. Heath MD Mark W. Head PhD Etienne Levavasseur PhD Richard Knight MD Jean‐Louis Laplanche PharmD PhD Jan PM. Langeveld PhD James W. Ironside MD Jean‐Jacques Hauw MD Jan Mackenzie Annick Alpérovitch MD Robert G. Will MD Stéphane Haïk MD PhD 《Annals of neurology》2009,65(3):249-256
129.
We tested the hypothesis that natriuretic peptide precursor A gene polymorphisms are significantly associated with blood pressure progression and incident hypertension among healthy, middle-aged women. We performed a prospective cohort study among 18 437 white women participating in the Women's Health Study who were free of hypertension at baseline. Two previously characterized single nucleotide polymorphisms within the natriuretic peptide precursor A gene (rs5063 G>A and rs5065 T>C) were genotyped. Blood pressure progression at 48 months and incident hypertension during the entire follow-up according to the different genotypes and inferred haplotypes were assessed by logistic regression and Cox proportional hazards models, respectively. At 48 months, 47.4% of women had blood pressure progression. The odds ratio (95% CIs) for blood pressure progression associated with the rs5063 variant was 0.85 (0.76 to 0.94; P=0.002). For the rs5065 variant, the corresponding odds ratio was 0.94 (0.88 to 1.00; P=0.050). During 9.8 years of follow-up, 29.6% of women developed incident hypertension. Hazard ratios (95% CIs) for incident hypertension were 0.88 (0.80 to 0.96; P=0.005) for the rs5063 variant and 0.95 (0.90 to 1.00; P=0.068) for the rs5065 variant. The odds ratios (95% CIs) of blood pressure progression for the G-T, G-C, and A-T haplotypes were 1.0 (referent), 0.91 (0.85 to 0.98; P=0.007), and 0.80 (0.71 to 0.89; P<0.001), respectively. For incident hypertension, the corresponding hazard ratios were 1.0 (referent), 0.95 (0.90 to 1.01; P=0.095), and 0.90 (0.81 to 0.99; P=0.031), respectively. If corroborated by other large-scale, prospective studies, our findings indicate that the natriuretic peptide precursor A gene plays a significant role in blood pressure regulation and development of hypertension. 相似文献
130.
C-reactive protein (CRP) levels are a complex phenotype with both genetic and environmental determinants. Recent work has
highlighted the impact of genetic variants within the CRP gene as well as other candidate genes, often chosen for their role in the inflammatory pathway, on CRP levels. Emerging work
shows the association of such genetic variants in CRP not only to CRP levels, but also to variation of CRP levels in the acute phase response. Work on the relation of genetic
variants within CRP to cardiovascular disease has had varied results. Whole-genome association studies to investigate the genetic determinants
of CRP levels in an unbiased manner are ongoing. 相似文献