全文获取类型
收费全文 | 36547篇 |
免费 | 2038篇 |
国内免费 | 107篇 |
专业分类
耳鼻咽喉 | 455篇 |
儿科学 | 2140篇 |
妇产科学 | 737篇 |
基础医学 | 4656篇 |
口腔科学 | 818篇 |
临床医学 | 2584篇 |
内科学 | 7391篇 |
皮肤病学 | 843篇 |
神经病学 | 1982篇 |
特种医学 | 846篇 |
外科学 | 5098篇 |
综合类 | 1349篇 |
一般理论 | 15篇 |
预防医学 | 2140篇 |
眼科学 | 1566篇 |
药学 | 3531篇 |
中国医学 | 276篇 |
肿瘤学 | 2265篇 |
出版年
2023年 | 243篇 |
2022年 | 682篇 |
2021年 | 1189篇 |
2020年 | 656篇 |
2019年 | 878篇 |
2018年 | 1069篇 |
2017年 | 734篇 |
2016年 | 970篇 |
2015年 | 1014篇 |
2014年 | 1367篇 |
2013年 | 1780篇 |
2012年 | 2458篇 |
2011年 | 2497篇 |
2010年 | 1403篇 |
2009年 | 1253篇 |
2008年 | 1817篇 |
2007年 | 1790篇 |
2006年 | 1803篇 |
2005年 | 1432篇 |
2004年 | 1418篇 |
2003年 | 1219篇 |
2002年 | 1034篇 |
2001年 | 835篇 |
2000年 | 878篇 |
1999年 | 740篇 |
1998年 | 313篇 |
1997年 | 217篇 |
1996年 | 226篇 |
1995年 | 221篇 |
1994年 | 181篇 |
1993年 | 152篇 |
1992年 | 500篇 |
1991年 | 407篇 |
1990年 | 433篇 |
1989年 | 399篇 |
1988年 | 357篇 |
1987年 | 356篇 |
1986年 | 348篇 |
1985年 | 323篇 |
1984年 | 262篇 |
1983年 | 219篇 |
1979年 | 230篇 |
1978年 | 148篇 |
1977年 | 180篇 |
1976年 | 140篇 |
1975年 | 172篇 |
1974年 | 182篇 |
1973年 | 183篇 |
1972年 | 173篇 |
1971年 | 161篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The natural history of occult spinal dysraphism in children is one of progressive and unpredictable neurological deficit. The modern role of neurosurgery is in the prevention of deterioration rather than correction of established disability. A prospective study was carried out on 40 consecutive patients to analyse the referral pattern of children with this condition. The age, reason for referral, clinical history and source of referral was recorded in each case. The reason for referral varied with age. Of the 40 patients studied, only 12 were found to be without neurological deficit at the time of referral. The incidence of progressive neurological deterioration increased with increasing age. The referral source in different age groups varied, but in all age groups relatively few were referred by the general paediatricians or paediatric neurologists. For optimum surgical results, early referral and treatment is desirable and should become our objective. 相似文献
92.
A new antibiotic, SQ 30,957, 4-diazo-3-methoxy-2,5-cyclohexadien-1-one, has been isolated from fermentation broths of Penicillium funiculosum. The structure (1) was deduced from its spectroscopic properties and its degradation reaction. SQ 30,957 has excellent activity against anaerobic bacteria such as Clostridium and Bacteroides and has moderate activity against aerobic bacteria. The compound has an LD50 of less than 17 mg/kg in mice by intraperitoneal administration. 相似文献
93.
Raymond Cochrane Sukhwant Singh Bal 《Social psychiatry and psychiatric epidemiology》1987,22(4):181-191
Summary Data are presented on rates of admission for schizophrenia for the native born and the four largest foreign born populations living in England in 1981 (Irish, Indian, Pakistani and Caribbean born). These data show that, in general, the foreign born have higher rates of admission for schizophrenia, and a higher proportion of all diagnoses accounted for by this disorder than do the native born. The exception is Pakistani born women who have conspicuously low rates. Five hypotheses are examined to account for these differences. The apparently high rates of schizophrenia found for the Indian born of both sexes, and Pakistani born men can be accounted for to a large extent by the demographic differences that exist between them and the native born. The Irish born residents of England have rates comparable with the Irish in Ireland who also show much higher rates than do the native English. There is no completely satisfactory account for the very high rates found for Caribbean born men and women but a combination of adverse post migration experiences and tendency to misdiagnose schizophrenia in this group is offered as a tentative explanation for at least some of the excess. The low rates of admission for schizophrenia of Pakistani women is attributed to a tendency on their part to opt out of the formal mental health system after an initial encounter, possibly to return to their native land. 相似文献
94.
95.
In the present study 108 full time workers employed in various sections of a railway workshop and exposed to smoke and irritant fumes, and 45 matched control subjects from local administrative staff were investigated to find prevalence of chronic bronchitis. In all 18 (16.7%) workers and 4 (8.9%) control subjects had clinical evidence of chronic bronchitis. Peak expiratory flow rate less than 300 L/min was observed in 54.6% workers and 2.2% control subjects. A significantly higher prevalence of chronic bronchitis was seen in workers. The advancing age, smoking and duration of exposure had significant influence on prevalence of chronic bronchitis. 相似文献
96.
97.
Magnetic field tomography of coherent thalamocortical 40-Hz oscillations in humans. 总被引:20,自引:6,他引:14
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
U Ribary A A Ioannides K D Singh R Hasson J P Bolton F Lado A Mogilner R Llinás 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(24):11037-11041
This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible the three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, we illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects. 相似文献
98.
Summary A newly designed attachment device of the multipurpose head frame (Sugita) for Neuronavigator (Watanabe) is presented with an illustrative case of glioblastoma in an eloquent area. This has extended the usefulness of the neuronavigator for those who prefer and use the multipurpose head frame, while the requirements for keeping a stereotactic combination and the original concept of the multipurpose head frame, as well as that of the neuronavigator have been kept undisturbed. 相似文献
99.
Malathion induced changes in the serum proteins and hematological parameters of an Indian catfish Heteropneustes fossilis (Bloch) 总被引:2,自引:0,他引:2
100.
N. C. Sharma R. Bhatia S. Singh P. C. John S. Kumar H. Singh 《Epidemiology and infection》1994,112(1):45-49
A total of 675 strains of Salmonella bareilly received from different parts of India and France during 1959-92 were phage typed using six bacteriophages. Overall typability achieved was 90.8% with 23 distinct phage types excluding a group of untypable strains. Phage types have been defined in octal code. Simpson''s coefficient was applied for diversity index having a value of 0.839. This system was found to be reproducible, stable and epidemiologically useful. 相似文献