全文获取类型
收费全文 | 1721508篇 |
免费 | 140947篇 |
国内免费 | 25794篇 |
专业分类
耳鼻咽喉 | 21227篇 |
儿科学 | 49889篇 |
妇产科学 | 45677篇 |
基础医学 | 238323篇 |
口腔科学 | 42915篇 |
临床医学 | 170370篇 |
内科学 | 330939篇 |
皮肤病学 | 36282篇 |
神经病学 | 134373篇 |
特种医学 | 65327篇 |
外国民族医学 | 676篇 |
外科学 | 241470篇 |
综合类 | 81806篇 |
现状与发展 | 79篇 |
一般理论 | 512篇 |
预防医学 | 129147篇 |
眼科学 | 40900篇 |
药学 | 130107篇 |
336篇 | |
中国医学 | 20596篇 |
肿瘤学 | 107298篇 |
出版年
2022年 | 17056篇 |
2021年 | 26931篇 |
2020年 | 18759篇 |
2019年 | 22289篇 |
2018年 | 27699篇 |
2017年 | 22377篇 |
2016年 | 23374篇 |
2015年 | 29974篇 |
2014年 | 39837篇 |
2013年 | 48338篇 |
2012年 | 67503篇 |
2011年 | 73093篇 |
2010年 | 43658篇 |
2009年 | 39011篇 |
2008年 | 60780篇 |
2007年 | 63422篇 |
2006年 | 63939篇 |
2005年 | 62188篇 |
2004年 | 54028篇 |
2003年 | 51149篇 |
2002年 | 48317篇 |
2001年 | 79151篇 |
2000年 | 81515篇 |
1999年 | 69552篇 |
1998年 | 22232篇 |
1997年 | 20729篇 |
1996年 | 19761篇 |
1995年 | 18597篇 |
1994年 | 16519篇 |
1993年 | 14578篇 |
1992年 | 48243篇 |
1991年 | 45519篇 |
1990年 | 43299篇 |
1989年 | 41124篇 |
1988年 | 37494篇 |
1987年 | 36425篇 |
1986年 | 33762篇 |
1985年 | 32008篇 |
1984年 | 24235篇 |
1983年 | 20303篇 |
1982年 | 12390篇 |
1979年 | 20849篇 |
1978年 | 14623篇 |
1977年 | 12147篇 |
1976年 | 11405篇 |
1975年 | 11661篇 |
1974年 | 14048篇 |
1973年 | 13577篇 |
1972年 | 12669篇 |
1971年 | 11496篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
本文报告用间接免疫荧光法检测特异性IgG抗体对流行性出血热的诊断意义。53例不同病期的出血热患者的血清,其间接荧光抗体的阳性率为49/53(占92.45%)。有77.36%的患者血清,检出IgG抗体的时间是在发病后的1~2周。血清中IgG的滴度与疾病的严重性无密切相关。另25例非EHF患者,其血清特异性IgG抗体均为阴性。可见检测特异性IgG抗体对EHF的诊断颇为有用。 相似文献
994.
A H Myers B Rosner H Abbey W Willet M J Stampfer C Bain R Lipnick C Hennekens F Speizer 《American journal of public health》1987,77(5):628-630
We analyzed smoking behavior of 91,651 married female nurses, aged 30-55 years in 1976. The prevalence of smoking was similar among all birth cohorts. The largest percentage increase in starting to smoke occurred between ages 15 and 25 years; by age 25, 50 per cent had started smoking. The cessation rate was lowest in earlier birth cohorts and among nurses starting to smoke at earlier ages. The cessation rate increased substantially between 1963-73 compared with the period 1948-58. 相似文献
995.
P M Schulz S C Schulz S C Goldberg P Ettigi R J Resnick R O Friedel 《The Journal of nervous and mental disease》1986,174(8):457-463
Relatives of 22 schizotypal probands were evaluated for lifetime psychiatric diagnoses. Forty-four (N = 44) of the 97 available relatives were interviewed directly using the Diagnostic Interview Schedule. The rates of psychiatric diagnoses were compared with those of sixty-six (N = 66) of 140 relatives of 30 depressed patients. Family history of mental illness was ascertained by the informant method on the remainder of relatives of both proband groups. The rate of depression found in the relatives of schizotypal patients was 52% in those directly interviewed and 25.7% when informants' reports on unavailable relatives are pooled with direct interview data. These rates were not significantly higher than those found for the relatives of depressed probands (34.8% by direct interview and 21% including reports from informants). The high rates of depression in the relatives of schizotypal probands may indicate that schizotypal personality is associated with affective disorder and not only with schizophrenia. However, the high rates may be due to the presence of depressive character traits in relatives, which inflate the rates of dysthymic disorder and other chronic depressive disorders in the relatives of borderline patients. 相似文献
996.
Numerous surveys at the national and regional level have demonstrated that large inequalities in infant health status exist in Southern Africa. Few studies have assessed infant mortality at the intra-urban scale of geographic analysis. Comparisons between infant mortality rates from different areas are made even more meaningful if the data are divided into two primary categories based on period-of-death; these being the neonatal and post-neonatal components. This study presents the results of a survey undertaken in Metropolitan Cape Town (population 1.6 million) during 1982. The aim was to determine the spatial variation of neonatal and post-neonatal mortality at the suburb (or community) level within the city. Overall, a total of 36,789 live births and 928 infant deaths were recorded; 53.4% in the neonatal period and 46.6% in the post-neonatal period. The mean infant mortality rate was 25.2 per 1000 live births; the neonatal mortality rate and post-neonatal mortality rate being 13.5/1000 and 11.7/1000, respectively. A marked range in death rates was evident for both components. For the neonatal category it was 0.0-49.9/1000 and 0.0-40.0/1000 for the post-neonatal period. The generally low post-neonatal mortality rate among the 69 suburbs studied has made the neonatal component the dominant contributor to the infant mortality rate. However, in the lowest socio-economic areas the post-neonatal mortality rate was responsible for over 60% of infant deaths.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
997.
998.
999.
1000.
Nerve growth factor (NGF) and NGF receptors were measured in cortex and hippocampus of rats treated with drugs affecting cholinergic neurotransmission. High (Kd= 0.045nM) and low (Kd= 21nM) affinity125I-NGF binding sites were present in both cortical and hippocampal membranes with hippocampus containing higher numbers of both sites than cortex. Chronic treatment of rats with the muscarinic receptor antagonist scopolamine (5 mg/kg, twice daily) decreased the density of high- and low-affinity sites by 50–90% in cortical and hippocampal membranes. These changes were seen after 7 days, but not 3 days, of scopolamine treatment. Chronic infusion of physostigmine (1 mg/kg/day) using minipumps increased the number of high- and low-affinity sites in cortex 3- and 6-fold, respectively. The changes in receptor-binding parameters induced by physostigmine were transient as they were evident after 3 days of treatment, but returned to control levels after 7 days. NGF content in cortex and hippocampus was reduced by about 50% following 7, but not 3, days of chronic physostigmine infusion. In contrast, scopolamine treatment failed to change NGF levels in the cholinergic neuronal target regions but it decreased NGF content in the septal area. The content of NGF mRNA in the cortex measured by Northern blot analysis failed to change following either scopolamine or physostigmine treatment. The results suggest that levels of NGF and NGF receptors in the target regions of cholinergic neurons are regulated by the extent of cholinergic neurotransmitter activity. 相似文献