全文获取类型
收费全文 | 2586233篇 |
免费 | 189311篇 |
国内免费 | 7558篇 |
专业分类
耳鼻咽喉 | 34374篇 |
儿科学 | 85272篇 |
妇产科学 | 71621篇 |
基础医学 | 363939篇 |
口腔科学 | 69775篇 |
临床医学 | 234821篇 |
内科学 | 515938篇 |
皮肤病学 | 62488篇 |
神经病学 | 213627篇 |
特种医学 | 99986篇 |
外国民族医学 | 736篇 |
外科学 | 386800篇 |
综合类 | 50482篇 |
现状与发展 | 5篇 |
一般理论 | 971篇 |
预防医学 | 196564篇 |
眼科学 | 56700篇 |
药学 | 188225篇 |
9篇 | |
中国医学 | 5334篇 |
肿瘤学 | 145435篇 |
出版年
2021年 | 20011篇 |
2019年 | 20670篇 |
2018年 | 29319篇 |
2017年 | 22628篇 |
2016年 | 26255篇 |
2015年 | 29538篇 |
2014年 | 40492篇 |
2013年 | 60509篇 |
2012年 | 80347篇 |
2011年 | 84620篇 |
2010年 | 51071篇 |
2009年 | 49194篇 |
2008年 | 79113篇 |
2007年 | 83960篇 |
2006年 | 85689篇 |
2005年 | 81850篇 |
2004年 | 78839篇 |
2003年 | 76160篇 |
2002年 | 73441篇 |
2001年 | 128482篇 |
2000年 | 131395篇 |
1999年 | 110570篇 |
1998年 | 31281篇 |
1997年 | 27949篇 |
1996年 | 28238篇 |
1995年 | 27403篇 |
1994年 | 25092篇 |
1993年 | 23444篇 |
1992年 | 85217篇 |
1991年 | 81680篇 |
1990年 | 78869篇 |
1989年 | 76111篇 |
1988年 | 69534篇 |
1987年 | 68045篇 |
1986年 | 63596篇 |
1985年 | 60566篇 |
1984年 | 44987篇 |
1983年 | 37978篇 |
1982年 | 22482篇 |
1981年 | 20011篇 |
1979年 | 39011篇 |
1978年 | 27474篇 |
1977年 | 23285篇 |
1976年 | 21529篇 |
1975年 | 22853篇 |
1974年 | 26834篇 |
1973年 | 25410篇 |
1972年 | 23788篇 |
1971年 | 21991篇 |
1970年 | 20216篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
P M Warwick 《European journal of clinical nutrition》1988,42(5):437-444
This study was conducted to follow up healthy subjects from a previous study (Warwick & Williams, 1987) in which favourable dietary changes were achieved during 1 week immediately after dietary advice but were accompanied by reduced energy intakes and weight loss. Twenty-one subjects (8m, 13f; 57 per cent of the original group) participated in the follow-up study. Dietary intakes were measured using 7-d weighed records on three occasions: before, immediately after and 1 year after receiving dietary advice. Intakes 1 year after dietary advice continued to show some of the favourable changes observed immediately after the advice but were not accompanied by reduced energy intakes and weight loss. Intakes before, immediately after, and 1 year after dietary advice respectively were: energy, 9.0, 7.8 and 8.9 MJ/d (2150, 1860 and 2120 kcal/d); fat, 36.9, 32.9 and 31.5 per cent of total energy; carbohydrate, 44.2, 47.9 and 49.6 per cent of total energy; dietary fibre, 32, 36 and 36 g/d; sodium, 116, 97 and 110 mmol/d; and Na:K ratio, 1.4, 1.2 and 1.2 mmol. Nutrient densities for fibre and most micronutrients tended to be higher 1 year after dietary advice than before, but were highest immediately after the advice. Nutrient densities for sodium and total sugars did not vary between the 3 study weeks. It was concluded that our healthy subjects adapted their intakes to maintain energy balance while retaining favourable dietary changes for at least 1 year after dietary advice. 相似文献
993.
994.
995.
A comparative study of two preservative-free tear substitutes in the management of severe dry eye 总被引:1,自引:0,他引:1
M Y Laflamme R Swieca 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》1988,23(4):174-176
Between mid-May and mid-July 1987 we performed a prospective crossover study of two unit-dose preservative-free artificial tear solutions, 1.4% polyvinyl alcohol (Refresh) and 0.1% sodium hyaluronate (Hylorin) in 14 female patients with severe dry eye syndrome. The patients were examined before treatment and after each of two trials with both products. A significant reduction in the mean score for dry-eye-induced keratitis (p = 0.001) and for mucous strands (p = 0.03) was observed following the second of two trials with sodium hyaluronate. A significant reduction in the mean score for burning and irritation was observed with both solutions (p = 0.009). We believe that the elimination of preservatives from artificial tear preparations may substantially reduce the iatrogenic effects of these frequently applied medications. 相似文献
996.
Mr. Charles V. Clark M.D. David J. Ewing 《Documenta ophthalmologica. Advances in ophthalmology》1988,70(4):309-321
Ocular autonomic function was assessed in 4 patients with progressive autonomic failure (PAF) and age-matched control subjects, by measurement of the pupil cycle time, and determination of autonomic denervation hypersensitivity of the iris. Pupil cycle time was abnormal in all patients with PAF; sustained pupil cycling was absent in 5 of the 8 eyes tested of the PAF patients, compared with only 16 eyes from 70 control subjects. Pupil constriction in response to 2.5% methacholine, indicative of parasympathetic denervation hypersensitivity, was significantly increased in patients with PAF (p < 0.001), whilst pupil dilation in response to 0.5% phenylephrine, indicative of sympathetic denervation hypersensitivity, was also significantly higher in the PAF patients (p < 0.001). The results suggest that ocular autonomic function may provide a sensitive early indicator of generalised autonomic dysfunction. 相似文献
997.
998.
J. M. Falletta B. Cushing S. Lauer B. Bell D. H. Mahoney R. Castleberry R. A. Krance 《Investigational new drugs》1990,8(2):167-170
Summary We conducted a phase I clinical study of aziridinylbenzoquinone (Diaziquone, AZQ) given as a 4 hour infusion weekly × 4. Forty-five children with recurrent acute leukemia and 33 children with various advanced solid tumors participated. Severe myelosuppression was the dose limiting toxic effect, occurring in all patients at the upper dose levels. Gastrointestinal and hepatic toxicities were infrequent and not severe. No allergic reactions occurred. Objective tumor regression was noted in 3 of 25 patients with a CNS tumor and in 6 of 45 patients with acute leukemia. For phase II trials the recommended dosage of Diaziquone given by this schedule is 18 mg/M2×4 for patients with a solid tumor, and is 30 mg/M2/week × 4 for children with acute leukemia. 相似文献
999.
Meral T. Ercan Nedim C. M. Gülaldi Işil S. Ünsal Mehmet Aydin İrfan Peksoy Zafer Hasçelik 《Annals of nuclear medicine》1996,10(4):419-423
The present study evaluated99mTc(V) DMSA as an agent for the visualization of inflammatory lesions in comparison to99mTc(HI) DMSA and99mTc-HIG. All three radiopharmaceuticals were prepared with commercial kits.99mTc(V) DMSA was prepared at neutral pH by the addition of first bicarbonate and then pertechnetate to the kit contents. The labeling efficiency was 99% as determined by ITLC. Abscesses were induced by i.m. injection of 50 μl turpentine into the right thighs of 36 Swiss albino mice. Six days later 3.7 MBq of each radiopharmaceutical was i.v. administered to 12 mice. The mice were sacrificed at 1,3,6 and 24 h later. Scintigrams were obtained with a gamma camera. The abscesses were better visualized on scintigrams with99mTc(V) DMSA compared to99mTc(III) DMSA, starting at 1 h. The animals were dissected and the organs were removed, weighed and the radioactivity determined with a gamma counter. The abscess to other tissue ratios were higher with99mTc(V) DMSA than the other radiopharmaceuticals. The max. abscess/muscle ratios were 9.46 ± 3.20 (24 h), 4.19 ± 1.39 (6 h) and 5.98 ± 1.17 (24 h) and max. abscess/blood ratios were 6.22 ± 1.41, 4.09 ± 0.84 and 0.914 ± 0.351 all at 24 h for99mTc(V) DMSA,99mTc(III) DMSA and99mTc-HIG, respectively. Experimental arthritis was produced in 6 New Zealand white rabbits by intra-articular injection of ovalbumin. Four days later 37 MBq of99mTc(V) DMSA and99mTc-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h clearly demonstrated arthritic joints. ROFs over arthritic joints were compared to contralateral normal joints (A/C). The max. A/C ratios were 2.10 ± 0.31 (3 h) and 2.92 ± 0.99 (24 h) for99mTc(V) DMSA and99mTc-HIG, respectively. Our results indicated the feasibility of imaging inflammatory lesions with99mTc(V) DMSA. 相似文献
1000.
B. A. Johnson Donald R. Jasinski Gantt P. Galloway Henry Kranzler Robert Weinreib Raymond F. Anton Barbara J. Mason Michael J. Bohn Helen M. Pettinati Richard Rawson Christopher Clyde 《Psychopharmacology》1996,128(2):206-215
Four hundred and twenty-three alcohol dependent subjects were enrolled into a 12-week randomized, double-blind, placebo-controlled
study to determine the safety and efficacy of the 5-HT2 receptor antagonist, ritanserin (2.5 mg/day or 5 mg/day), in reducing alcohol intake and craving. All subjects received 1
week of single-blind placebo prior to randomization into the 11-week double-blind phase. Additionally, all subjects received
weekly individual sessions of manual-guided cognitive-behavioral therapy. Comparing the single-blind period with endpoint,
there was approximately a 23% reduction in drinks/day; 34% fall in the total number of drinking days/week; 22% decrease in
drinks/drinking day; and a 37% diminution in alcohol craving for all treatment groups. All treatment groups experienced a
beneficial clinical outcome as assessed by the Clinical Global Impression Scale. There was, however, no significant difference
between treatment groups on any of these measures of alcohol drinking, craving, or clinical outcome. Subjects were of relatively
high social functioning at baseline, and this did not change significantly during treatment. Treatment groups did not differ
significantly on either medication compliance or reported adverse events. Ritanserin treatment was associated with a dose-related
prolongation of subjects’ QTc interval recording on the electrocardiogram. These results suggest that alcohol dependent subjects
can show marked clinical improvement within a structured alcohol treatment program. These findings do not support an important
role for ritanserin in the treatment of alcohol dependence.
Received: 30 April 1996/Final version: 3 July 1996 相似文献