全文获取类型
收费全文 | 1308236篇 |
免费 | 99143篇 |
国内免费 | 5201篇 |
专业分类
耳鼻咽喉 | 16697篇 |
儿科学 | 41463篇 |
妇产科学 | 35532篇 |
基础医学 | 194712篇 |
口腔科学 | 35723篇 |
临床医学 | 123610篇 |
内科学 | 254329篇 |
皮肤病学 | 27782篇 |
神经病学 | 104143篇 |
特种医学 | 48457篇 |
外国民族医学 | 285篇 |
外科学 | 183147篇 |
综合类 | 33514篇 |
现状与发展 | 18篇 |
一般理论 | 573篇 |
预防医学 | 107660篇 |
眼科学 | 29229篇 |
药学 | 97115篇 |
36篇 | |
中国医学 | 4832篇 |
肿瘤学 | 73723篇 |
出版年
2021年 | 11649篇 |
2019年 | 11450篇 |
2018年 | 15099篇 |
2017年 | 11832篇 |
2016年 | 12659篇 |
2015年 | 15054篇 |
2014年 | 20505篇 |
2013年 | 29636篇 |
2012年 | 40698篇 |
2011年 | 43378篇 |
2010年 | 25129篇 |
2009年 | 23963篇 |
2008年 | 39932篇 |
2007年 | 42662篇 |
2006年 | 42197篇 |
2005年 | 41110篇 |
2004年 | 39213篇 |
2003年 | 37739篇 |
2002年 | 36468篇 |
2001年 | 57357篇 |
2000年 | 58221篇 |
1999年 | 49363篇 |
1998年 | 14258篇 |
1997年 | 13026篇 |
1996年 | 13269篇 |
1995年 | 12490篇 |
1994年 | 11607篇 |
1992年 | 38537篇 |
1991年 | 37951篇 |
1990年 | 36707篇 |
1989年 | 35469篇 |
1988年 | 32899篇 |
1987年 | 32194篇 |
1986年 | 30668篇 |
1985年 | 28874篇 |
1984年 | 22011篇 |
1983年 | 19224篇 |
1982年 | 11381篇 |
1979年 | 20950篇 |
1978年 | 15393篇 |
1977年 | 12790篇 |
1976年 | 11845篇 |
1975年 | 12811篇 |
1974年 | 15588篇 |
1973年 | 15362篇 |
1972年 | 14512篇 |
1971年 | 13552篇 |
1970年 | 12786篇 |
1969年 | 12066篇 |
1968年 | 11229篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
901.
902.
E W Richards M Abu Khaled C L Watkins C L Long 《Nutrition (Burbank, Los Angeles County, Calif.)》1991,7(5):344-346
Nuclear magnetic resonance (NMR) spectroscopy has been reported as an alternative method for quantitating deuterium oxide concentrations in the evaluation of total-body-water in humans. However, the presence of dissolved plasma proteins results in an underestimation of deuterium NMR (2H-NMR) intensity ratios, thereby causing an overestimation (5-6%) of total-body-water (TBW) values determined from nonsublimed patient plasma samples. We demonstrate that plasma samples must be corrected for the volume percentage of water in plasma. Correction of initial 2H-NMR intensity ratios with a factor of 0.93 results in intensity ratios comparable to those determined from plasma samples subjected to vacuum sublimation to remove all plasma solutes. 相似文献
903.
904.
Electronystagmography (ENG) was performed on 127 dizzy patients and the findings were compared with the diagnosis obtained with a comprehensive neurological test battery. ENG was found to be abnormal in 49 (39%) of the patients: 19 with unilateral vestibular hyporeactivity, eight with directional preponderance, 12 with spontaneous or undirectional positional nystagmus, eight with abnormal smooth pursuit, and 13 with other abnormalities. Among the patients with abnormal ENGs, established central nervous system lesions were found in 28 cases (19 of these infratentorial lesions); nine peripheral vestibular lesions and five undefined vestibular lesions were found. Patients with normal ENGs showed fewer peripheral vestibular lesions and more dizziness of psychogenic aetiology. Almost half the patients with infratentorial lesions had normal ENGs. Patients with rotatory vertigo had fewer ENG abnormalities than those with other types of dizziness. These results suggest that ENG alone is of limited value in the diagnosis of dizziness. A comprehensive test battery is needed to establish the diagnosis. 相似文献
905.
The paper reviews existing reports on relations between pathologies leading to malabsorption and dental lesion in children. The following dental alterations are reported in the literature: delayed eruption of deciduous teeth, hypoplasia of enamel and dental caries. These lesions have been observed in gastrointestinal pathologies, for example, coeliac disease, chronic diarrhea and recurrent vomiting, intolerance of cow's milk protein, Crohn's disease and salmonellosis. The delayed eruption of deciduous teeth and hypoplasia of the enamel are certainly correlated to malabsorption and maldigestion, especially if these are protracted over time. Dental caries may be due to poor oral hygiene, poor diet and to the presence of modified calcification. Only a comparative study with a control group will enable the effective prevalence to be assessed. 相似文献
906.
Taurine in pediatric nutrition: review and update 总被引:2,自引:0,他引:2
G E Gaull 《Pediatrics》1989,83(3):433-442
Taurine was long considered an end product of the metabolism of the sulfur-containing amino acids, methionine and cyst(e)ine. Its only clearly recognized biochemical role had been as a substrate in the conjugation of bile acids. Taurine is found free in millimolar concentrations in animal tissues, particularly those that are excitable, rich in membranes, and generate oxidants. Various lines of evidence suggest one major nutritional role as protecting cell membranes by attenuating toxic substances and/or by acting as an osmoregulator. The totality of evidence suggests that taurine is nonessential in the rodent, it is an essential amino acid in the cat, and it is conditionally essential in man and monkey. Absence from the diet of a conditionally essential nutrient does not produce immediate deficiency disease but, in the long term, can cause problems. Taurine is now added to many infant formulas as a measure of prudence to provide improved nourishment with the same margin of safety for its newly identified physiologic functions as that found in human milk. Such supplementation can be justified by the finding of improved fat absorption in preterm infants and in children with cystic fibrosis, as well as by salutary effects on auditory brainstem-evoked responses in preterm infants. Experimental findings in animal models and in human cell models provide further justification for taurine supplementation of infant formulas. 相似文献
907.
L R Baker W J Mallinson M C Gregory E A Menzies W R Cattell H N Whitfield W F Hendry J E Wickham A M Joekes 《British journal of urology》1987,60(6):497-503
Sixty patients with idiopathic retroperitoneal fibrosis presenting between 1965 and 1984 are reviewed. Their mean age at presentation was 56 years and the male:female ratio was 3:1. The commonest presenting symptoms were flank and abdominal pain, weight loss, nausea and polyuria. Physical examination was usually normal, expect for the presence of hypertension. Anaemia and elevation of erythrocyte sedimentation rate were usually present. Proteinuria was found in less than a third of patients at presentation and significant bacteriuria was uncommon. The correct diagnosis was made or suspected in very few patients before referral. The cumulative actuarial survival rate was 86% at 1 year and 78% at 2 years. Seventeen patients died; they were significantly older and more uraemic at the time of referral than those who survived. A few patients did well with either corticosteroid therapy or ureterolysis alone. In the majority, both operation and steroid treatment were necessary. In bilateral obstruction with residual function in both kidneys, bilateral ureterolysis proved superior to unilateral operation (each followed by steroid therapy) in conserving renal function. Operation alone or steroid therapy alone should be considered in cases where steroids or surgery respectively present particular hazards. The less traumatic unilateral operation should be considered in poor risk patients and in those whose renal function is absent on one side. In many survivors, disease activity has persisted for many years. Life-long follow-up is recommended. 相似文献
908.
909.
910.