全文获取类型
收费全文 | 739140篇 |
免费 | 51628篇 |
国内免费 | 1473篇 |
专业分类
耳鼻咽喉 | 9447篇 |
儿科学 | 23925篇 |
妇产科学 | 18110篇 |
基础医学 | 114799篇 |
口腔科学 | 20814篇 |
临床医学 | 66058篇 |
内科学 | 142905篇 |
皮肤病学 | 16705篇 |
神经病学 | 51921篇 |
特种医学 | 26902篇 |
外国民族医学 | 76篇 |
外科学 | 110943篇 |
综合类 | 14978篇 |
现状与发展 | 2篇 |
一般理论 | 160篇 |
预防医学 | 52521篇 |
眼科学 | 16720篇 |
药学 | 56350篇 |
3篇 | |
中国医学 | 2481篇 |
肿瘤学 | 46421篇 |
出版年
2021年 | 6097篇 |
2019年 | 5949篇 |
2018年 | 8509篇 |
2017年 | 6612篇 |
2016年 | 7399篇 |
2015年 | 8208篇 |
2014年 | 11109篇 |
2013年 | 16370篇 |
2012年 | 22073篇 |
2011年 | 23177篇 |
2010年 | 13661篇 |
2009年 | 12691篇 |
2008年 | 21457篇 |
2007年 | 23073篇 |
2006年 | 23473篇 |
2005年 | 22046篇 |
2004年 | 21635篇 |
2003年 | 20494篇 |
2002年 | 20031篇 |
2001年 | 37581篇 |
2000年 | 38055篇 |
1999年 | 31535篇 |
1998年 | 8366篇 |
1997年 | 7055篇 |
1996年 | 7312篇 |
1995年 | 6939篇 |
1994年 | 6393篇 |
1992年 | 23743篇 |
1991年 | 23671篇 |
1990年 | 22932篇 |
1989年 | 22790篇 |
1988年 | 20625篇 |
1987年 | 19951篇 |
1986年 | 19034篇 |
1985年 | 17817篇 |
1984年 | 13030篇 |
1983年 | 11044篇 |
1982年 | 6075篇 |
1979年 | 11764篇 |
1978年 | 8326篇 |
1977年 | 7000篇 |
1976年 | 6719篇 |
1975年 | 7443篇 |
1974年 | 8653篇 |
1973年 | 8290篇 |
1972年 | 7785篇 |
1971年 | 7262篇 |
1970年 | 7001篇 |
1969年 | 6443篇 |
1968年 | 5897篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
971.
972.
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
973.
A structured discourse strategy, employing child echoic imitations and adult expansion, was used to teach 5 autistic children two-term semantic relations. The 5 male preschoolers in late Stage I of linguistic development were exposed systematically to two-term semantic relations in a structured dialogue with a clinician. A combined multiple baseline and AB(A) design was used to examine the relationship between the clinician expansions and the children's subsequent spontaneous imitations and spontaneous productions. The results showed that an increase in modeling and expansion was related to an increase in the children's initial spontaneous imitations of two-term relations. Further, following the increase in spontaneous imitations, spontaneous productions of the two-term relations increased and were maintained, whereas spontaneous imitations subsequently decreased. 相似文献
974.
975.
Sixty children aged 5-13 years with moderately severe asthma took part in a double-blind, placebo-controlled trial of ketotifen. The design incorporated a 22 week study period, the addition of ketotifen or placebo to the current medication, and a controlled withdrawal of the regular therapy. Children receiving ketotifen showed significantly lower mean numbers of asthma attacks and less absence from school. The addition of ketotifen to existing treatment was associated with marginally significant changes in rates of day and night wheezing. In the second phase of study, additional therapy was withdrawn from both the ketotifen and placebo groups which resulted in a high (percentage) withdrawal. Children receiving ketotifen did not have a significantly lower failure rate than those given placebo. 相似文献
976.
P. T. Wakode P. L. Joshi M. N. Mahore 《Indian journal of otolaryngology and head and neck surgery》1989,41(4):138-140
Nasal Cytogram is a simple, economical and reliable investigation. Although its utility was recognised as early s1927, it has not gained much popularity. Here an attempt is madeto assess the efficacy of nasal cytology in the light of histology, to diagnose various nasal conditions.127 cases of common rhinological problem were studied at Govt. Medical College, Nagpur. This investigation was found to be simple,
reliable & economical. 相似文献
977.
978.
979.
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
980.
The effects of sulfated cholecystokinin (CCK-8S) and glucose on insulin secretion and polyphosphoinositide (PPI) metabolism were studied in isolated rat islets. Both agonists stimulate PPI hydrolysis, inositol phosphate accumulation, 3H efflux from [3H]inositol-prelabeled tissue, and 45Ca efflux from prelabeled cells. However, the effects of CCK-8S on PPI metabolism are considerably greater than those of glucose. Furthermore, the effects of CCK-8S on PPI and Ca2+ metabolism are observed whether islets are incubated in either 2.75 or 7 mM glucose, but CCK-8S only stimulates insulin secretion (a biphasic response) when the higher glucose concentration is present. Addition of 1 microM forskolin to islets incubated in media containing 2.75 mM glucose does not influence basal insulin secretion but sensitizes the islets to the action of CCK-8S. In the presence of forskolin, CCK-8S induces a very marked first phase but no second phase of insulin secretion. We postulate that CCK-8S acts in this tissue via receptor-linked PPI hydrolysis, leading to an inositol trisphosphate-induced Ca2+ efflux. These receptor-mediated effects of CCK-8S are not altered either by the ambient glucose concentration or the cAMP content of the islets, but these two factors determine the responsiveness of the islets (in terms of insulin secretion) to a given CCK-8S signal. 相似文献