全文获取类型
收费全文 | 215247篇 |
免费 | 18567篇 |
国内免费 | 4807篇 |
专业分类
耳鼻咽喉 | 3263篇 |
儿科学 | 4128篇 |
妇产科学 | 3587篇 |
基础医学 | 17369篇 |
口腔科学 | 7235篇 |
临床医学 | 19907篇 |
内科学 | 21248篇 |
皮肤病学 | 2428篇 |
神经病学 | 10556篇 |
特种医学 | 5810篇 |
外国民族医学 | 11篇 |
外科学 | 20631篇 |
综合类 | 34659篇 |
现状与发展 | 9篇 |
一般理论 | 24篇 |
预防医学 | 28979篇 |
眼科学 | 2014篇 |
药学 | 21007篇 |
344篇 | |
中国医学 | 26295篇 |
肿瘤学 | 9117篇 |
出版年
2024年 | 958篇 |
2023年 | 4312篇 |
2022年 | 8058篇 |
2021年 | 10598篇 |
2020年 | 10379篇 |
2019年 | 11575篇 |
2018年 | 10233篇 |
2017年 | 8819篇 |
2016年 | 7875篇 |
2015年 | 7348篇 |
2014年 | 14434篇 |
2013年 | 14732篇 |
2012年 | 12998篇 |
2011年 | 13873篇 |
2010年 | 11209篇 |
2009年 | 9672篇 |
2008年 | 9008篇 |
2007年 | 9075篇 |
2006年 | 7762篇 |
2005年 | 6579篇 |
2004年 | 5478篇 |
2003年 | 4850篇 |
2002年 | 3738篇 |
2001年 | 3111篇 |
2000年 | 2734篇 |
1999年 | 2261篇 |
1998年 | 1803篇 |
1997年 | 1612篇 |
1996年 | 1314篇 |
1995年 | 1257篇 |
1994年 | 1145篇 |
1993年 | 1015篇 |
1992年 | 931篇 |
1991年 | 843篇 |
1990年 | 745篇 |
1989年 | 725篇 |
1988年 | 679篇 |
1987年 | 613篇 |
1986年 | 546篇 |
1985年 | 1813篇 |
1984年 | 2094篇 |
1983年 | 1310篇 |
1982年 | 1739篇 |
1981年 | 1209篇 |
1980年 | 1034篇 |
1979年 | 916篇 |
1978年 | 750篇 |
1977年 | 555篇 |
1976年 | 701篇 |
1975年 | 481篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Ihsan A. Badr 《International ophthalmology》1993,17(3):155-160
The region is characterized by diversity in cultural, political, economic and health conditions. Blindness in the region varies from 6.4% to 0.2% with cataract ranking highly as an underlying cause. There is a need to develop national policies to deliver affordable, technically suitable, and cost effective management plans to reduce cataract. Economic, demographic, health, and manpower statistics are essential information to be considered in formulating such policies. 相似文献
42.
鼻部源性突眼的CT分析 总被引:1,自引:0,他引:1
目的:为了提高对鼻部源性突眼的认识。材料和方法:本文19例鼻部源性突眼,其中鼻咽癌7例,鼻咽纤维血管瘤2例,鼻腔纤维血管瘤、恶性肉芽肿和嗅神经母细胞瘤各1例,上颌窦癌和软骨肉瘤各2例,上颌窦恶性肉芽肿、纤维肉瘤和恶性纤维组织细胞瘤各1例,全部病例均作轴位CT扫描,12例加作增强扫描,详细分析了它们CT表现。结果:源于鼻咽的放疗前鼻咽癌和纤维血管瘤,其病变主要位于鼻咽腔和咽旁,后者显著增强并有钙斑,与前者不同;源于上颌窦的肿瘤,病变占据上颌窦的全部或大部分,软骨肉瘤有钙斑且无强化,易与其它肿瘤区别,它们破坏上颌窦顶部进入眼眶;鼻腔嗅神经母细胞瘤在鼻腔和筛窦形成肿块,破坏筛骨眶板侵入眼眶。结论:根据CT所见,可判断突眼原因。 相似文献
43.
Sarah A. Taylor Jacqueline Benedetti David Schuller Stephen P. Richman Goronwy O. Broun Alexander Hantel 《Investigational new drugs》1993,11(2-3):227-229
Summary Twenty-two patients with recurrent or metastatic squamous cell carcinoma of the head and neck were treated with piroxantrone 150 mg/m2 intravenously every 21 days. There were no objective responses. The 95% upper confidence bound for response is 15%. Primary toxicity was hematologic. 相似文献
44.
Rosemary Cant 《Australian Occupational Therapy Journal》1993,40(3):113-121
Newer policies of community care for those with disabilities have resulted in the home becoming the usual site of care. Policy makers must now give attention to the needs of those at home giving this care. This article explores the constraints on sociability opportunities of 73 mothers who were caring for children with disabilities. These opportunities are often built into leisure pursuits for women without caring responsibilities. However, choice of out-of-house leisure activity was circumscribed for the mothers in this study and their reported leisure activities revolved around home and neighbourhood. Even these sites offered limited scope for sociability because of the way in which caring affected domestic space and because of the characteristics of the modern Australian suburb. It is argued in this paper that personal time and personal domestic space are needed by care-givers so their sociability needs can be fulfilled. An understanding of the constraints imposed by use of the home as a place of care may make possible the planning of a rearrangement of domestic space to increase sociability opportunities for carers. 相似文献
45.
T. M. Skerry M.D. M.R.C.V.S. R. Suswillo A. J. El Haj N. N. Ali R. A. Dodds L. E. Lanyon 《Calcified tissue international》1990,46(5):318-326
Summary Previous studies of Alcian blue-induced birefringence in adult avian cortical bone showed that a short period of intermittent
loading rapidly produces an increased level of orientation of proteoglycans within the bone tissue. In the absence of further
loading, this persists for over 24 hours. We have proposed that this phenomenon could provide a means for “capturing” the
effects of transient strains, and so provide a persistent, constantly updated strain-related influence on osteocyte populations
related to the bones' averaged recent strain history, in effect, a “strain memory” in bone tissue. In our present study, we
use the Alcian blue-induced birefringence technique to demonstrate that proteoglycan orientation also occurs after intermittent
loading of both cortical and cancellous mammalian bonein vivo andin vitro. We also show that the change in birefringence is proportional to the magnitude of the applied strain, and that the reorientation
occurs rapidly, reaching a maximal value after only 50 loading cycles. Examination of electron micrographs of bone tissue
after staining with cupromeronic blue allows direct visualization and quantification of the change in proteoglycan orientation
produced by loading. This shows that intermittent loading is associated with a realignment of the proteoglycan protein cores,
bringing them some 5 degrees closer to the direction of collagen fibrils in the bone matrix. 相似文献
46.
放射性肝纤维化过程的定量研究 总被引:6,自引:0,他引:6
经^60Coγ线照射大鼠肝区,通过光镜、电镜和图像分析仪、宣研究了照后1年肝脏的病理改变。结果表明,30Gy组在照射后1年内逐渐发生了放射性肝纤维化病变。在肝纤维化发生过程中,肝细胞内糖原颗凿含量进行性减少,间质中胶原纤维含量进行性增加,网状纤维于照射1-3个月呈进行性增加。 相似文献
47.
A. G. D. Maran J. A. Wilson M. N. Gaze 《European archives of oto-rhino-laryngology》1993,250(3):127-132
Summary Squamous cell carcinoma of the head and neck is a disease predominantly of males and is due to a variety of known environmental irritants, notably cigarette smoke. Dietary, viral and immunological factors may also be relevant. Head and neck squamous cancers express epidermal growth factor receptors and some show weak levels of oestrogen receptor activity, but a reliable serum marker of tumour burden remains to be identified. The prognosis is found to be less favourable in females, in those with advanced T stage, in association with multiple node involvement, especially where extracapsular spread is present and where the T4/T8 ratio is elevated. Administration of heterologous blood during therapy may also have an adverse effect on prognosis. Interested clinicians must remember that most cases are preventable.
Correspondence to: A.G.D. Maran 相似文献
48.
49.
目的:在原核系统中表达并纯化大肠杆菌胞嘧啶脱氨酶(cytosine deaminase,CD),制备鼠抗大肠杆菌CD多克隆抗体,方法:亚克隆CD基因到原核表达载体pMAL-c2和pBV222中,并转化入大肠杆菌DH5α内,诱导表达并纯化MBP-CD和6his-CD融合蛋白,用纯化的MBP-CD融合蛋白免疫小鼠制备多克隆抗体。结果:通过重组质粒的酶切筛选出重组阳性克隆,成功地表达和纯化出MBP-CD和6his-CD融合蛋白,用纯化的MBP-CD成功制备了鼠抗CD多克隆抗体,并用6his-CD和GST-CD重组蛋白进行Western印迹分析,证实了抗体的正确性,结论:应用多克隆抗体可以检测体内外CD基因的表达,为临床前和临床上深入开展CD基因的生物治疗研究提供重要的实验材料。 相似文献
50.
This report describes a model for identifying sets of teaching abilities considered to be effective for medical school teaching staff, based on roles teachers assume and functions they are expected to perform as instructors. The specification of these teaching abilities was the first step in the development of a comprehensive course on Medical Instruction at the Basic Institute of Medical and Agricultural Biology of the State University of Sao Paulo, Botucatu, Brazil, where the senior author is employed. The work was based on the assumption that medical school teachers are expected to assume a variety of teaching roles and that identification and specification of the abilities that define their roles can result in more effective and efficient teaching. 相似文献