全文获取类型
收费全文 | 608篇 |
免费 | 31篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 8篇 |
妇产科学 | 15篇 |
基础医学 | 48篇 |
口腔科学 | 16篇 |
临床医学 | 116篇 |
内科学 | 134篇 |
皮肤病学 | 67篇 |
神经病学 | 37篇 |
特种医学 | 1篇 |
外科学 | 73篇 |
综合类 | 2篇 |
一般理论 | 2篇 |
预防医学 | 29篇 |
眼科学 | 3篇 |
药学 | 76篇 |
肿瘤学 | 6篇 |
出版年
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 13篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2011年 | 5篇 |
2010年 | 20篇 |
2009年 | 23篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 16篇 |
1997年 | 23篇 |
1996年 | 37篇 |
1995年 | 22篇 |
1994年 | 22篇 |
1993年 | 32篇 |
1992年 | 26篇 |
1991年 | 32篇 |
1990年 | 13篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 20篇 |
1986年 | 23篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 13篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1971年 | 4篇 |
1967年 | 3篇 |
1965年 | 5篇 |
1963年 | 3篇 |
1961年 | 4篇 |
1959年 | 4篇 |
1958年 | 11篇 |
1957年 | 13篇 |
1956年 | 7篇 |
1955年 | 16篇 |
1954年 | 5篇 |
1949年 | 9篇 |
1948年 | 5篇 |
排序方式: 共有639条查询结果,搜索用时 15 毫秒
1.
Psychometric data are presented which examine the validity of using the concentration of benzoylecgonine in urine, a major metabolite of cocaine, as a measure of drug use, in studies of drug abuse treatments. In such research the standard biological indicator of drug use is usually a qualitative urine drug test, which merely indicates the presence or absence of a drug or its metabolite. A quantitative (i.e. continuous) outcome measure, such as the concentration of a drug or its metabolite in a biological fluid, has substantially more statistical power than a dichotomous measure and should, therefore, prove a more sensitive measure of drug use when viewed from a measurement perspective. Data from two placebo-controlled clinical trials of fluoxetine as an adjunct to treatment for cocaine abuse are analyzed to address this issue. Results indicate that urine benzoylecgonine level is closely related to self-reports of drug use and is independent of levels of anxiety, depression and hopelessness. 相似文献
2.
CHARLES STEADMAN CLINTON TEAGUE PAUL KERLIN OWEN HARRIS KEVIN HOURIGAN JOHN SAMPSON 《Journal of gastroenterology and hepatology》1987,2(5):459-466
Collagenous colitis is characterized by the presence of a thick subepithelial collagen band in the colonic mucosa. The condition was diagnosed on rectal biopsy in 10 patients (one male, nine females) who presented with watery diarrhoea. Although rectal mucosal erythema was present in three and ulceration in two, the mucosa was of normal endoscopic appearance in five of the patients. There was marked variability in the thickness of the submucosal collagen band, both between and within individuals. Empirical drug therapy included sulphasalazine, glucocorticoids and antidiarrhoeals. All patients reported symptomatic improvement. 相似文献
3.
4.
HELEN J. GILL JAMES L. MAGGS STEPHEN MADDEN MUNIR PIRMOHAMED & B. KEVIN PARK 《British journal of clinical pharmacology》1996,42(3):347-353
1 Cytochrome P450-mediated bioactivation of sulphamethoxazole to a hydroxylamine has been implicated in the hypersensitivity reactions associated with co-trimoxazole administration. Inhibiting the formation of the hydroxylamine may be one method of preventing the high frequency of toxicity which is observed in HIV-infected patients. Therefore, in this study, we have investigated the ability of fluconazole and ketoconazole, known cytochrome P450 inhibitors, to inhibit the formation of sulphamethoxazole hydroxylamine.
2 Ten healthy male volunteers were given co-trimoxazole (800 mg sulphamethoxazole and 160 mg trimethoprim) alone or 1 h after either fluconazole (150 mg) or ketoconazole (200 mg) in a randomized fashion with a washout period of at least 1 week between each phase. Urine was collected for 24 h, and sulphamethoxazole and its metabolites were quantified by electrospray LC-MS.
3 Ketoconazole had no effect on the urinary recovery of sulphamethoxazole or any of its metabolites. In contrast, fluconazole significantly ( P <0.001) inhibited the formation of sulphamethoxazole hydroxylamine by 50.0±15.1%. Fluconazole also inhibited the oxidation of sulphamethoxazole to the 5-methylhydroxy and 5-methylhydroxy acetate metabolites by 69.9±15.8% and 64.0±12.0%, respectively, but had no effect on the amount of sulphamethoxazole, N4 -acetyl sulphamethoxazole, or sulphamethoxazole N1 -glucuronide excreted in urine.
4 The potential clinical benefit of using fluconazole to prevent hypersensitivity to co-trimoxazole in patients with AIDS needs to be assessed in a prospective study using both metabolite formation and the clinical occurrence of adverse reactions as end-points. 相似文献
2 Ten healthy male volunteers were given co-trimoxazole (800 mg sulphamethoxazole and 160 mg trimethoprim) alone or 1 h after either fluconazole (150 mg) or ketoconazole (200 mg) in a randomized fashion with a washout period of at least 1 week between each phase. Urine was collected for 24 h, and sulphamethoxazole and its metabolites were quantified by electrospray LC-MS.
3 Ketoconazole had no effect on the urinary recovery of sulphamethoxazole or any of its metabolites. In contrast, fluconazole significantly ( P <0.001) inhibited the formation of sulphamethoxazole hydroxylamine by 50.0±15.1%. Fluconazole also inhibited the oxidation of sulphamethoxazole to the 5-methylhydroxy and 5-methylhydroxy acetate metabolites by 69.9±15.8% and 64.0±12.0%, respectively, but had no effect on the amount of sulphamethoxazole, N
4 The potential clinical benefit of using fluconazole to prevent hypersensitivity to co-trimoxazole in patients with AIDS needs to be assessed in a prospective study using both metabolite formation and the clinical occurrence of adverse reactions as end-points. 相似文献
5.
JOHN P. BOURKE LYNNE HOWELL ALAN MURRAY WILLIAM E. HILL J. CAMPBELL COWAN KEVIN BEATT JOAN ERRINCTON STUART JAMESON RONALD G. GOLD 《Pacing and clinical electrophysiology : PACE》1989,12(8):1419-1425
A randomized prospective study was undertaken to compare the electrical performances of three permanent, endocardial, tined pacing leads with different electrode designs--sintered platinum, vitreous carbon, and porous carbon. Ninety-nine patients received one of the leads (S80 31; 423S 32; S100 36). Acute R wave amplitude and ST elevation of the native endocardial electrogram, voltage threshold, impedance, and current flow at four pulse durations (0.25-1.0 msec) were measured. Voltage thresholds were measured noninvasively at each of four pulse durations at 2 days and 1, 3, and 6 months after implantation. No significant differences were found in sensing properties, or current flow at threshold at 0.5 msec pulse duration. The 423S lead had a significantly higher impedance at threshold and both a higher impedance and lower current flow at 5 V. No significant differences in threshold voltages were found between the three leads at any pulse duration, at any of the assessed times after implantation. Six-month thresholds for the S80, 423S, and S100 leads were 1.18 +/- 0.35, 1.17 +/- 0.29, and 1.06 +/- 0.38 V respectively at 0.5 msec pulse duration. Differences between 'high performance' pacing leads need to be of a greater order of magnitude before they can be exploited to give any real clinical advantage to patients. 相似文献
6.
Purified secretory acetylcholinesterase (sAChE) from Trichostrongylus colubriformis was used as a candidate vaccine against mixed T. colubriformis, Haemonchus contortus and C. oncophora challenge infections of sheep. Cross species protection was achieved with an average reduction in worm burden of all species of 31%, rising to 58% in individual cases. There was no consistent reduction in faecal egg counts and increases in anti-T. colubriformis sAChE IgG antibody levels following vaccination were modest. We suggest that improved antigen delivery systems will result in increased host protection. 相似文献
7.
KEVIN R. BISHOP MSN ARNP MOLLY DOUGHERTY Ph D ARNP RUTH MOONEY Ph D ARNP PHYLLIS GIMOTTY Ph D BRADFORD WILLIAMS MD 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1992,21(5):401-406
OBJECTIVE: To examine factors that affect pelvic muscle response to 12 weeks of pelvic muscle exercise. DESIGN: Repeated measures design in which intravaginal pressures during pelvic muscle contractions were recorded at baseline and after four exercise levels. SETTING: College of Nursing research site in Gainesville, Florida. PARTICIPANTS: Eighty-five parous, community-dwelling women, aged 35-78 years and without incontinence as a primary concern. INTERVENTIONS: A 12-week graded program of regular (three times per week, every other day) pelvic muscle exercise at home. MAIN OUTCOME MEASURES: The hypotheses were that younger age, lower parity, higher baseline intravaginal pressures, and adherence to the pelvic muscle exercise program each would result in significant improvement in maximum intravaginal pressures. RESULTS: The only factor showing significance in predicting a successful outcome was age (t = -2.29, df = 41, one-tail probability = .0136). CONCLUSIONS: Regular, graded exercise over several weeks is needed to build pelvic muscles, and some women who exercise do not improve. Although the reasons for not improving are unclear, age is a significant factor. 相似文献
8.
9.
KEVIN RYAN M.D. RAJAT S. SANYAL M.D. LUIZ PINHEIRO M.D. NAVIN C. NANDA M.D. 《Echocardiography (Mount Kisco, N.Y.)》1992,9(3):277-285
Our experience in using biplane transesophageal echocardiography in the assessment of coarctation of the aorta is described. 相似文献
10.
Parents of young babies attended evening classes on prevention of sleeping problems in pre-school children. The aim was to test the consumer-appeal of this preventative approach. Content focused on individual behavioural differences in babies as well as adaptation of parenting strategies to avoid some of the common pitfalls in the management of sleep-related behaviours. Parents' views were obtained and were favourable. Results are discussed in terms of the timing and format of similar prevention programmes. 相似文献