全文获取类型
收费全文 | 637篇 |
免费 | 42篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 27篇 |
妇产科学 | 11篇 |
基础医学 | 57篇 |
口腔科学 | 15篇 |
临床医学 | 98篇 |
内科学 | 182篇 |
皮肤病学 | 11篇 |
神经病学 | 27篇 |
特种医学 | 47篇 |
外科学 | 66篇 |
综合类 | 26篇 |
预防医学 | 60篇 |
眼科学 | 3篇 |
药学 | 43篇 |
肿瘤学 | 20篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2018年 | 4篇 |
2016年 | 8篇 |
2015年 | 19篇 |
2014年 | 21篇 |
2013年 | 18篇 |
2012年 | 16篇 |
2011年 | 10篇 |
2010年 | 31篇 |
2009年 | 24篇 |
2008年 | 15篇 |
2007年 | 23篇 |
2006年 | 10篇 |
2005年 | 16篇 |
2004年 | 7篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 12篇 |
1998年 | 32篇 |
1997年 | 20篇 |
1996年 | 25篇 |
1995年 | 12篇 |
1994年 | 16篇 |
1993年 | 15篇 |
1992年 | 8篇 |
1991年 | 18篇 |
1990年 | 9篇 |
1989年 | 21篇 |
1988年 | 17篇 |
1987年 | 12篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1975年 | 5篇 |
1959年 | 15篇 |
1958年 | 16篇 |
1957年 | 14篇 |
1956年 | 10篇 |
1955年 | 15篇 |
1954年 | 19篇 |
1952年 | 5篇 |
1948年 | 4篇 |
排序方式: 共有698条查询结果,搜索用时 15 毫秒
21.
Scollon EJ Carr JA Rintoul DA McMurry ST Cobb GP 《Environmental toxicology and chemistry / SETAC》2012,31(2):336-346
This study evaluated the interactions of flight, fasting, and 1,1,1-trichloro-bis(4-chlorophenyl)ethane (p,p'-DDT) loading on residue metabolism and distribution in recently exposed white-crowned sparrows (Zonotrichia leucophrys). Female sparrows were dosed with 5 mg p,p'-DDT per kg body weight over 3 d. Following 1 d of recovery, sparrows were flown in a wind tunnel for up to 140 min, in 15-min blocks. Food was withheld from the start of the flight period until birds were euthanized. DDT, 1,1-dichloro-2,2-bis(4 chlorophenyl)ethane (DDD), and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) were present in all tissues examined. 1-Chloro-2,2-bis(4-chlorophenyl)ethene (DDμ), 1,1-bis(4-chlorophenyl)ethane (p,p'-DDη), and 2,2-bis(4-chlorophenyl)ethanol (p,p'-DDOH) were not found. Fasting did not significantly affect the rate of residue increase over time in any of the tissues examined. When sparrows flew and fasted simultaneously, fasting seldom contributed to an increase in tissue residues. However, the length of time flown was significantly correlated with increasing toxicant concentrations in the brain, kidney, and liver, effectively demonstrating the potential for brief flights to enhance mobilization of DDT and its metabolites. Dose, flight, and fasting also increased residues in brain tissue. These contaminant redistributions may have important ramifications on the stresses experienced by migratory birds. 相似文献
22.
23.
24.
25.
Effects of a fat-containing meal on sex hormones in men 总被引:1,自引:0,他引:1
A W Meikle J D Stringham M G Woodward M P McMurry 《Metabolism: clinical and experimental》1990,39(9):943-946
The effect of a fat-containing meal on plasma sex steroid concentrations was investigated in normal men. After an overnight fast on two separate occasions, subjects ingested a liquid meal containing either a nonnutritive sweetener (control), or isocaloric meals of mixed calorie sources with either high-fat content or mixed carbohydrate and protein with minimal fat. The order of the meals was alternated. Blood samples were collected at 15-minute intervals and pooled each hour. Sampling began at 7:00 AM and the test meal was ingested at 8:00 AM. Sex steroids, including estrone, estradiol, testosterone, and dihydrotestosterone (DHT), sex hormone-binding globulin (SHBG) capacity, free testosterone concentration, and luteinizing hormone (LH) were determined by either specific radioimmunoassay or dialysis. The fat-containing meal, but not the nonnutritive or mixed carbohydrate and protein meal, resulted in a significant (P less than .01) reduction in total and free testosterone. Estrogens and luteinizing hormone were unaffected by either meal. This is the first documentation, to our knowledge, of the acute effect of a fat-containing meal on sex steroid concentrations in blood. Our observations suggest that a fat-containing meal reduces testosterone concentrations without affecting luteinizing hormone. This might indicate that fatty acids modulate testosterone production by the testes. 相似文献
26.
A. Lonardo P. Loria F. Leonardi A. Borsatti P. Neri M. Pulvirenti A. M. Verrone A. Bagni M. Bertolotti D. Ganazzi N. Carulli POLI.ST.E.N.A. Study Group 《Digestive and liver disease》2002,34(3):204-211
BACKGROUND: Non-alcoholic fatty liver disease is a common reason for hepatological consultation and may herald severe hepatic and extra-hepatic disease. The aetiopathogenesis of this condition is an area of increasing interest. AIM: To evaluate anthropometric and biochemical factors associated to non-alcoholic fatty liver disease in a case-control study. Methods. Demographic and biochemical data of 60 consecutive patients with bright liver absent-to-low alcohol consumption, no evidence of viral, genetic and autoimmune diseases, were compared to those of 60 age- and gender-matched historical controls without fatty liver by univariate and multiple logistic regression analysis. RESULTS: Patients were more often hypertriglyceridaemic, obese and diabetic than controls (p<.01). Mean values of alanine transaminase, gammaglutamyltranspeptidase, triglycerides, uric acid, fasting and log insulin, transferrin percent saturation and ferritin were significantly higher in the patients, while transferrin and quantitative insulin sensitivity check index, a quantitative insulin sensitivity index, were lower. No iron storage was found in those who underwent liver biopsy At univariate analysis the relative risk for non-alcoholic fatty liver disease significantly increased (p<0. 05) with increasing body mass index, fasting insulin, alanine transaminase, uric acid, triglycerides and gammaglutamyltranspeptidase; it decreased with increasing transferrin and quantitative insulin sensitivity check index. Multiple logistic regression analysis disclosed only fasting insulin and uric acid to be independent predictors of non-alcoholic fatty liver disease (p<0.05). CONCLUSIONS: Fasting insulin and serum uric acid levels indicating insulin resistance, but not indices of iron overload, are independent predictors of non-alcoholic fatty liver disease. 相似文献
27.
Silvio ST Tafuri Domenico DM Martinelli Giovanni GC Caputi Annamaria AA Arbore Cinzia CG Germinario Rosa RP Prato 《BMC health services research》2009,9(1):100-5
Background
Mandatory vaccination has contributed to the success of immunisation programmes but voluntary vaccination allows people to be responsible for their own health. There are benefits from both policies and the arguments between them remain subject to debate within and without the scientific community, both nationally and internationally. The aim of this study is to assess the opinions of those who actually work in the Vaccination Service. 相似文献28.
目的 探讨血管新生指标CD34、CD31、vWF、Ⅳ型胶原纤维及层粘连蛋白在肝细胞肝癌(HCC)中的表达及意义 ,同时比较上述几种血管新生因子与增殖细胞核抗原 (PCNA)、病理指标及预后的相关性 ,以便筛选出有效的临床预后指标。方法 采用免疫组化方法 ,对 5 3例肝细胞肝癌的标本进行CD31、CD34、vWF、Ⅳ型胶原纤维及层粘连蛋白的染色、计数 ,并用检测数据与患者的临床资料进行统计分析。结果 统计染色的血管面积后发现 ,CD34与多种临床病理指标无相关性 ;CD31与肝内门静脉浸润相关 ;vWF与肿瘤的TNM分期及肝内门静脉浸润呈正相关 ;CollⅣ与肝内门静脉浸润呈正相关、与术后生存期呈负相关 ;Lam与肝硬化及术中出血量呈负相关、与术后生存期呈正相关。PCNA与肿瘤TNM分期有关。结论 在HCC中 ,CollⅣ、vWF、及CD31为肝细胞肝癌的有效血管新生及预后指标 ;Lam则与肝硬化及术中出血相关 ;PCNA指数肿瘤分期有关 ;CD34不能用作血管新生或预后指标 相似文献
29.
FLORIAN STÖCKIGT M.D. JAN W. SCHRICKEL M.D. RENÉ ANDRIÉ M.D. LARS LICKFETT M.D. 《Journal of cardiovascular electrophysiology》2012,23(11):1254-1257
Atrioesophageal Fistula After Cryoballoon PV Isolation . The risk of atrioesophageal fistula after cryoballoon pulmonary vein isolation is thought to be much lower than after radiofrequency ablation, seeing that no data exist on this complication so far. We report for the first time on the occurrence of an atrioesophageal fistula 4 weeks after cryoballoon ablation at the site of the left inferior pulmonary vein. We suggest that even when using cryothermal ablation technique, an imaging modality to assess the proximity of esophagus and left atrium should be routinely performed to avoid this fatal complication. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1254–1257, November 2012) 相似文献
30.
Labial adhesions are usually seen in early childhood or in the postmenopausal years, but this clinical entity is rarely seen in the reproductive years. We report a case of labial adhesion with acute urinary retention secondary to Bartholin's abscess in a reproductive‐aged woman with normal menstrual periods. We emphasize the possible occurrence of labial adhesion following Bartholin's abscess in the reproductive years with normal estrogen levels. 相似文献