全文获取类型
收费全文 | 536395篇 |
免费 | 27943篇 |
国内免费 | 506篇 |
专业分类
耳鼻咽喉 | 6723篇 |
儿科学 | 17033篇 |
妇产科学 | 12757篇 |
基础医学 | 93565篇 |
口腔科学 | 12459篇 |
临床医学 | 48982篇 |
内科学 | 96765篇 |
皮肤病学 | 12008篇 |
神经病学 | 34805篇 |
特种医学 | 20096篇 |
外国民族医学 | 54篇 |
外科学 | 78772篇 |
综合类 | 7650篇 |
现状与发展 | 2篇 |
一般理论 | 108篇 |
预防医学 | 39038篇 |
眼科学 | 11995篇 |
药学 | 41944篇 |
1篇 | |
中国医学 | 1141篇 |
肿瘤学 | 28946篇 |
出版年
2021年 | 3987篇 |
2018年 | 5822篇 |
2017年 | 4204篇 |
2016年 | 4971篇 |
2015年 | 5483篇 |
2014年 | 7276篇 |
2013年 | 10698篇 |
2012年 | 15889篇 |
2011年 | 17692篇 |
2010年 | 10144篇 |
2009年 | 8998篇 |
2008年 | 15975篇 |
2007年 | 17715篇 |
2006年 | 17197篇 |
2005年 | 16547篇 |
2004年 | 16128篇 |
2003年 | 15509篇 |
2002年 | 15064篇 |
2001年 | 22622篇 |
2000年 | 23184篇 |
1999年 | 19114篇 |
1998年 | 5305篇 |
1997年 | 4418篇 |
1996年 | 4431篇 |
1995年 | 4175篇 |
1992年 | 14498篇 |
1991年 | 15887篇 |
1990年 | 16039篇 |
1989年 | 15737篇 |
1988年 | 14415篇 |
1987年 | 14280篇 |
1986年 | 13264篇 |
1985年 | 12791篇 |
1984年 | 9459篇 |
1983年 | 8059篇 |
1982年 | 4204篇 |
1979年 | 9016篇 |
1978年 | 6435篇 |
1977年 | 5204篇 |
1976年 | 5549篇 |
1975年 | 6662篇 |
1974年 | 7461篇 |
1973年 | 7224篇 |
1972年 | 6654篇 |
1971年 | 6377篇 |
1970年 | 5942篇 |
1969年 | 5525篇 |
1968年 | 5206篇 |
1967年 | 4657篇 |
1966年 | 3994篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
991.
992.
The objective of this study was to estimate the incidence of hip fracture in the canton of Vaud, Switzerland (total population 584 000), for the period 1986–1991 using routine hospital discharge data collected by the Cantonal Service of Statistical Research and Information (SCRIS). For the survey period, the estimated average annual crude incidence rate of hip fractures was 167 per 100 000 persons aged 20 or older (241 for women and 84 for men). For the population aged 50 years or older, the crude incidence rate was 388 per 100 000 persons (546 for women and 185 for men). The average annual age-specific rates rose exponentially by successive 5-year age groups. The median age of patients at the time of the fracture was 82 years in women and 74 years in men. There was no significant difference between the total number of cervical and trochanteric fractures. Between the ages of 20 and 84 years, the cumulative risk for a woman to be admitted to hospital with a hip fracture was twice that of a man (15.8% vs 7.8%). From 1986 to 1991, the age- and sex-adjusted incidence, like the ratio of cervical to trochanteric fractures, did not show any significant trend, although it was consistent with an increase in men (p=0.09). However, the annual number of fractures rose from 644 to 776, particularly among very aged men. The mean length of stay in the acute care hospital fell from 38 days in 1986 to 25 days in 1991. Finally, the comparison of these results with those obtained in 1986 for the same population from more exhaustive sources has confirmed the provision of a consistent, although overestimated, assessment of hip fracture incidence by means of these routine hospital statistics in the canton of Vaud, Switzerland. 相似文献
993.
994.
995.
J Alió M Lude?a A Millan V Caballero V Guinaldo 《Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift für Augenheilkunde》1988,196(4):192-199
The authors present the results of a transmission electron-microscopic study performed on a tissue sample obtained by an intraocular fine-needle aspiration biopsy in a case of retinoma. The ultrastructural study showed that the tumor was composed mainly of granular osmiophilic material which contained some tumor cells. These cells showed peculiar ultrastructural characteristics, which demonstrated their neural character, and appeared in different degenerative stages. Apparently, this is the first case in whom ultrastructural technique have been applied to study an intraocular tumor sample obtained by intraocular fine-needle aspiration biopsy, and the first case of retinoma studied by such a diagnostic approach. 相似文献
996.
V B Nakagawara 《Journal of the American Optometric Association》1988,59(12):925-928
An eye protection program is needed in occupational medicine policies. Typical eye injuries and eye accidents, as they relate to occupational accidents, justify the management advocating such a program. A recommended model for a functional eye protection program is provided and defined. 相似文献
997.
Central sensory and motor conduction in vitamin B12 deficiency. 总被引:7,自引:0,他引:7
V Di Lazzaro D Restuccia D Fogli R Nardone S Mazza P Tonali 《Electroencephalography and clinical neurophysiology》1992,84(5):433-439
Four patients with subacute combined degeneration were studied through upper and lower limb SEPs recorded with a non-cephalic reference montage and through cortical and spinal magnetic stimulation. Clinical signs were confined to the lower limbs in 3 patients; the remaining patient presented only paraesthesiae in 4 limbs. Median nerve SEPs showed a normal cervical N13 response with a significant increase of central conduction time concerning exclusively the P9-P14 interpeak interval. Central motor conduction to upper and lower limb muscles was abnormal. Nerve conduction studies provided no evidence of peripheral nerve involvement. These electrophysiological findings suggest that in vitamin B12 deficiency the higher segments of the cervical cord are usually affected first and that central sensory and motor conduction studies are sensitive methods for detecting such damage. 相似文献
998.
Disease processes in the peritoneum, omentum, and mesentery occasionally are not recognized at radiologic examination. The authors have used computed tomography (CT) to categorize the radiologic appearances of the more common abnormalities into three basic patterns: (a) solid but relatively well-defined masses, (b) cystic-appearing masses, and (c) ill-defined or infiltrative processes. The most common solid masses to affect these anatomic regions are secondary neoplasms, which are associated with enhancement of the peritoneum on contrast material-enhanced CT scans and, typically, ascites. The various cystic-appearing masses (including cystic lymphangioma, cystic mesothelioma, teratoma, and loculated ascites) and infiltrating masses (such as peritoneal mesothelioma, retractile mesenteritis, desmoid, and carcinoid) must be differentiated on the basis of clinical findings and additional imaging findings (eg, CT depiction of fat and calcium in teratomas and the radiating appearance of carcinoids). Although the CT appearances of some of the abnormalities overlap, classifying them by pattern is helpful in narrowing the range of the differential diagnosis. 相似文献
999.
We describe the types of aggressive behaviour and determine their prevalence in a sample of hospitalized elderly psychiatric patients. Data were obtained by nurse ratings of aggressive behaviour using the recently developed Rating Scale for Aggressive Behaviour in the Elderly; 90 patients were rated over a 3-d period. Nearly half the sample were at least mildly aggressive; the frequencies of some specific types of aggressive behaviour were high. In contrast, the frequency of injuries and the use of restraints and medication for aggressive behaviour were low. Some correlates of the aggressive behaviour were also analysed. 相似文献
1000.