全文获取类型
收费全文 | 2386608篇 |
免费 | 168327篇 |
国内免费 | 4471篇 |
专业分类
耳鼻咽喉 | 35194篇 |
儿科学 | 75482篇 |
妇产科学 | 69704篇 |
基础医学 | 340670篇 |
口腔科学 | 69882篇 |
临床医学 | 202661篇 |
内科学 | 464854篇 |
皮肤病学 | 52088篇 |
神经病学 | 187830篇 |
特种医学 | 93771篇 |
外国民族医学 | 778篇 |
外科学 | 369847篇 |
综合类 | 53050篇 |
现状与发展 | 7篇 |
一般理论 | 711篇 |
预防医学 | 170962篇 |
眼科学 | 56335篇 |
药学 | 181207篇 |
5篇 | |
中国医学 | 4989篇 |
肿瘤学 | 129379篇 |
出版年
2018年 | 21632篇 |
2015年 | 21463篇 |
2014年 | 29848篇 |
2013年 | 45718篇 |
2012年 | 60968篇 |
2011年 | 65080篇 |
2010年 | 38671篇 |
2009年 | 36856篇 |
2008年 | 62896篇 |
2007年 | 68453篇 |
2006年 | 69412篇 |
2005年 | 67788篇 |
2004年 | 65527篇 |
2003年 | 63606篇 |
2002年 | 62742篇 |
2001年 | 109038篇 |
2000年 | 112208篇 |
1999年 | 95304篇 |
1998年 | 26302篇 |
1997年 | 23799篇 |
1996年 | 23460篇 |
1995年 | 22163篇 |
1994年 | 20986篇 |
1993年 | 19312篇 |
1992年 | 75677篇 |
1991年 | 73978篇 |
1990年 | 72865篇 |
1989年 | 71110篇 |
1988年 | 66268篇 |
1987年 | 65109篇 |
1986年 | 62217篇 |
1985年 | 59247篇 |
1984年 | 44378篇 |
1983年 | 38104篇 |
1982年 | 22758篇 |
1981年 | 20437篇 |
1979年 | 42373篇 |
1978年 | 30087篇 |
1977年 | 26040篇 |
1976年 | 24083篇 |
1975年 | 26947篇 |
1974年 | 31900篇 |
1973年 | 30876篇 |
1972年 | 29565篇 |
1971年 | 27545篇 |
1970年 | 25860篇 |
1969年 | 24979篇 |
1968年 | 23482篇 |
1967年 | 20799篇 |
1966年 | 19437篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Summary. Twenty artificial periapical lesions confined to cancellous bone were prepared at the apices of first and second mandibular molars of human cadavers. The lesions emphasized removal of the lamina dura and preparation of a 'halo' lesion surrounding the root apex, plus the addition of a simulated sclerotic border. Radiographs taken before and after creation of the lesions were scored by three examiners for detectable lesions Cross-sections of the lesions were assessed for the extent of bone destruction. Periapical lesions confined to cancellous bone were detected in 80 per cent of cases, and the presence of a sclerotic border tended to enhance visualization, although not in all cases. Intentional cortical involvement also improved detection of lesions. The anatomical features of the periapical area appear to promote the visualization of lesions which might not be detected in other locations. 相似文献
992.
The thesis of this article is that deficits in language and communication contribute to behavior problems in childhood. Mentally retarded children show a range of deficits in language and communication compared with normals; they are also at increased risk for behavior problems. The evidence suggests that these deficits are quantitative rather than qualitative. In addition, these linguistic deficits may contribute independently to the development of behavior disorders insofar as the linguistic deficit interferes with the child's ability to make himself understood or to understand others. 相似文献
993.
Magnetic resonance imaging in planning limb-salvage surgery for primary malignant tumors of bone 总被引:4,自引:0,他引:4
M Sundaram M H McGuire D R Herbold M K Wolverson E Heiberg 《The Journal of bone and joint surgery. American volume》1986,68(6):809-819
In defining the linear extent of a malignant tumor in a long bone, radiographs, computerized tomography, and scintigraphy are routinely employed, especially when non-ablative surgery is being considered. The drawbacks of these modalities in defining the true intracompartmental extent of disease within a bone can largely be overcome with the use of magnetic resonance imaging. We did a prospective analysis of magnetic resonance imaging in sixteen consecutive patients with a primary malignant tumor of a long bone, and it showed that this modality has clinical promise of being more precise than the other modalities in defining the true proximal and distal extent of a tumor in a long bone. Coronal images permit easier planning of surgical techniques for salvage of a limb using an allograft than do a multiplicity of transverse images. 相似文献
994.
995.
M Herbst H Fritz H G Nüsslein B J Manger J R Kalden R Sauer 《Strahlentherapie und Onkologie》1986,162(1):25-30
Eleven patients with refractory rheumatoid arthritis were submitted to a total lymphoid irradiation up to a dose of 20 Gy. A constant improvement of clinical symptoms was observed in four out of the eleven patients already during the treatment and in the other patients not later than two months after. The frequency of attacks decreased and the number of joints involved in the attack was reduced. Morning rigidity and joint swellings decreased. One patient developed joint empyemas 4 and 26 months after the treatment. Four patients died in the meantime. In two patients the cause of death were renal insufficiency and a postoperative cardiogenic shock associated with generalized amyloidosis. The third patient died because of a toxically induced left cardiac decompensation with sepsis that could not be controlled by antibiotic drugs and multiple joint empyemas. The fourth patient developed an abscess after surgical treatment of a Kaposi syndrome. She died three months later from acute left cardiac decompensation. The therapy induced a lymphocytopenia with decrease of T helper lymphocytes and unchanged number of T suppressor lymphocytes. The constant therapy results of total lymphoid irradiation in primary chronic polyarthritis is probably due to this modification in the immune regulation. 相似文献
996.
997.
Anticoagulant drugs are known to have an effect on tumour growth. However, the mechanisms by which they act are poorly understood, and have therefore been investigated in this study. Wistar rats were given eight weekly subcutaneous injections of azoxymethane, at a dose of 10 mg kg-1 week-1. Following this they were randomized into two groups: a control group, which received no further treatment, and a warfarin treated group, which received warfarin at 'non-therapeutic' doses in their drinking water, for a further 8 weeks. Pairs of rats from each group were killed at 5-weekly intervals from 10 to 35 weeks after the first azoxymethane injection. At 40 weeks all remaining rats were killed. Samples of colonic mucosa from the descending colon and rectum were taken for scanning electron microscopy. The number of microadenomas per low power field was determined in both groups at each time interval. Tumour incidence and distribution were noted in animals killed at 40 weeks. The median number of microadenomas was significantly lower in warfarin treated animals than in controls at all time intervals. Tumour number was also significantly decreased by warfarin treatment (27 in azoxymethane treated animals, 10 in animals receiving azoxymethane and warfarin, P less than 0.05). The distribution of tumours along the colon was similar to that seen previously, following 12 weeks of azoxymethane. These effects occurred despite the non-concurrent administration of azoxymethane and warfarin. 相似文献
998.
G Bussone L La Mantia E A Parati F Frediani E Lamperti A Boiardi C Peccarisi A M Tortorano M A Viviani 《European neurology》1986,25(4):256-261
A case of cryptococcal meningoencephalitis, as presented by a hypertensive hydrocephalus, is described. To our knowledge, this is the 24th case described in Italy since 1953. The diagnosis was made with ventricular fluid examination: the patient was successfully treated with amphotericin B and 5-fluorocytosine, thus avoiding the risks of surgical treatment of hydrocephalus. Early diagnosis and proper therapy are necessary in order to decrease the high lethality of cryptococcosis. 相似文献
999.
Myectomy versus myotomy as an adjunct to membranectomy in the surgical repair of discrete and tunnel subaortic stenosis 总被引:1,自引:0,他引:1
J Lavee L Porat A Smolinsky J Hegesh H N Neufeld D A Goor 《The Journal of thoracic and cardiovascular surgery》1986,92(5):944-949
The results of membranectomy and deep myectomy in the left ventricular outflow tract were compared to those of membranectomy and myotomy in 42 patients who underwent surgical repair of discrete and tunnel subaortic stenosis. Fifteen consecutive patients (Group A) underwent membranectomy and myotomy, and 27 consecutive patients (Group B) underwent membranectomy and myectomy. Two patients of Group A and nine of Group B had tunnel subaortic stenosis. The preoperative mean (+/- standard deviation) peak systolic gradients across the left ventricular outflow tract in patients with discrete subaortic stenosis types I and II were 64 +/- 29 mm Hg in Group A and 52 +/- 3 mm Hg in Group B (p = not significant). In the patients with tunnel subaortic stenosis the preoperative mean gradients were 97 +/- 74 mm Hg in Group A and 73 +/- 26 mm Hg in Group B (p = not significant). In patients with discrete subaortic stenosis types I and II, postoperative catheterization at a mean follow-up of 21 months revealed residual mean gradients of 29 +/- 24 mm Hg in Group A and 10 +/- 13 mm Hg in Group B (p less than 0.01). In the patients with tunnel subaortic stenosis, the postoperative mean gradients were 25 +/- 7 and 30 +/- 30 mm Hg in Groups A and B, respectively (p = not significant). We conclude that in the surgical management of discrete subaortic stenosis types I and II, deep myectomy (in addition to membranectomy) produces better relief of the left ventricular outflow obstruction than do membranectomy and myotomy. In patients with tunnel subaortic stenosis myectomy is less effective than in the non-tunnel type but still produces acceptable results and may delay radical procedures to a later age. 相似文献
1000.
Osteomalacia and bone disease arising from aluminum 总被引:2,自引:0,他引:2