全文获取类型
收费全文 | 2180篇 |
免费 | 152篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 106篇 |
妇产科学 | 19篇 |
基础医学 | 242篇 |
口腔科学 | 134篇 |
临床医学 | 231篇 |
内科学 | 355篇 |
皮肤病学 | 43篇 |
神经病学 | 442篇 |
特种医学 | 147篇 |
外科学 | 210篇 |
综合类 | 107篇 |
一般理论 | 26篇 |
预防医学 | 139篇 |
眼科学 | 23篇 |
药学 | 153篇 |
中国医学 | 1篇 |
肿瘤学 | 59篇 |
出版年
2021年 | 19篇 |
2020年 | 13篇 |
2019年 | 27篇 |
2018年 | 26篇 |
2017年 | 22篇 |
2016年 | 35篇 |
2015年 | 23篇 |
2014年 | 45篇 |
2013年 | 78篇 |
2012年 | 66篇 |
2011年 | 78篇 |
2010年 | 64篇 |
2009年 | 62篇 |
2008年 | 79篇 |
2007年 | 140篇 |
2006年 | 79篇 |
2005年 | 94篇 |
2004年 | 83篇 |
2003年 | 61篇 |
2002年 | 63篇 |
2001年 | 57篇 |
2000年 | 64篇 |
1999年 | 83篇 |
1998年 | 70篇 |
1997年 | 50篇 |
1996年 | 41篇 |
1995年 | 41篇 |
1994年 | 41篇 |
1993年 | 55篇 |
1992年 | 56篇 |
1991年 | 59篇 |
1990年 | 65篇 |
1989年 | 72篇 |
1988年 | 69篇 |
1987年 | 47篇 |
1986年 | 53篇 |
1985年 | 49篇 |
1984年 | 26篇 |
1983年 | 31篇 |
1982年 | 20篇 |
1981年 | 14篇 |
1980年 | 24篇 |
1979年 | 20篇 |
1978年 | 30篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1975年 | 12篇 |
1973年 | 10篇 |
1967年 | 11篇 |
1966年 | 15篇 |
排序方式: 共有2443条查询结果,搜索用时 15 毫秒
1.
2.
顺铂聚乳酸微球的药物释放特性及肝动脉栓塞研究 总被引:5,自引:0,他引:5
对顺铂聚乳酸微球进行了体外药物释放和家犬肝动脉栓塞研究。该微球粒径范围为50~200μm,平均粒径为115.76±35.94μm,顺铂含量为37.16%(W/W);体外药物释放机制符合Higuchi方程;肝动脉栓塞后8h,肝组织顺铂浓度高达21.55±12.18μg/g,明显高于肝动脉灌注顺铂组:3.16±0.09μg/g(P<0.05);肝动脉栓塞组的顺铂血浓峰值、各取血点浓度及曲线下面积AUC皆低于肝动脉灌注顺铂组。可望达到提高栓塞部位的药物疗效,降低全身毒副反应的作用。 相似文献
3.
Changing attentional demands in left hemispatial neglect. 总被引:1,自引:0,他引:1
R F Kaplan M Verfaellie M E Meadows L R Caplan M S Pessin L D DeWitt 《Archives of neurology》1991,48(12):1263-1266
Seven variations of a letter cancellation test were used to examine how varying attentional demands affect hemispatial neglect in patients with right hemisphere lesions. While the 14 targets always remained in the same location, the number of distractors (zero, nine, 28, or 82) as well as their complexity (one letter or nine different letters) were varied. The percentage of targets canceled in the left hemispace was linearly related to the number of distractors. There were no differences between the complexity conditions. In a second study, the same 14 targets were presented but the distractors (zero, 14, or 41) were all placed on the right. Increasing the number of distractors on the right increased neglect on both sides of the space. Taken together, these results suggest that, while the limited attentional resources of the left hemisphere are biased toward the right hemispace, the absence of contralateral attentional demands allows these resources to be directed ipsilaterally. 相似文献
4.
PC Chamyal A Mehta SL Ojha JR Bhardwaj 《Indian journal of otolaryngology and head and neck surgery》1991,43(1):26-27
Primary tuberculous pathology in nasolpolypi is a rare condition. A case of bilateral ethmoidal polypi with tubercular lesion diagnosed on histopathologlcal examination is being reported and the available relevant literature has been reviewed. 相似文献
5.
Diagnosis and treatment of ischemic stroke 总被引:6,自引:0,他引:6
L R Caplan 《JAMA》1991,266(17):2413-2418
6.
7.
BACKGROUND: Many patients with asthma or chronic obstructive pulmonary diseaseuse their medication inhalers incorrectly. General practitioners,pharmacists and other health care providers do not always havethe opportunity to instruct patients in correct inhaler technique. OBJECTIVE: To find out whether the inhaler technique and respiratory symptomsof patients can be improved after instruction by practice assistants. METHODS: Single blind, randomized intervention study in which 48 patientswho had been using a dry powder inhaler for at least one monthtook part. Their inhaler technique was videotaped on two visitswith a two-week interval between visits. The inhaler techniqueon the videos was subsequently scored by two experts on ninecriteria. At both visits the patients completed a questionnaireabout their respiratory symptoms. After the first video, 25patients were randomly chosen to receive instruction from oneof six practice assistants who had followed a one evening courseabout inhaler instruction, and who had been issued an instruction-set. RESULTS: The patients who received instruction had a significantly greaterreduction in number of mistakes at the second visit than thepatients who did not (P = 0.01). The instructed patients alsoreported less dyspnoea at the second visit (P = 0.03). No effectof instruction was found on wheezing, cough and sputum production. CONCLUSION: The inhaler technique of patients can be improved significantlyby the instruction of patients by trained practice assistants,possibly resulting in less dyspnoea. Keywords. Administration-inhalation, obstructive lung diseases, airways symptoms, patient-education, general practice. 相似文献
8.
E Seidman N LeLeiko M Ament W Berman D Caplan J Evans S Kocoshis A Lake K Motil J Sutphen 《Journal of pediatric gastroenterology and nutrition》1991,12(4):424-438
Malnutrition, characterized by weight loss, growth failure and micronutrient depletion, are prominent features of inflammatory bowel disease (IBD) in the pediatric age group. Accurate evaluation of the patient's nutritional status and appropriate nutritional support, whether enteral or parenteral, constitute integral parts of the management of the growing child with IBD. Over the past two decades, a number of studies have supported the potential use of nutritional therapy to induce remission and to control disease activity in symptomatic Crohn's disease. More recently, preliminary studies on the use of dietary supplements of marine-oil-derived omega-3 fatty acids have also indicated a beneficial effect in IBD patients. In parallel with these clinical trials, scientific research has recently focused on the concept that specific dietary alterations can modulate the immune response. Components of the diet that may have particular relevance to mucosal immunity and the pathogenesis of IBD include polyunsaturated fatty acids, nucleotides, and amino acids such as glutamine and arginine. Future research in the interactions between specific nutrients and the immune system will likely increase our understanding of the causes of IBD, as well as enhance the development of novel nutritional therapies for IBD patients. 相似文献
9.
Kinnison ML; Perler BA; Kaufman SL; Mitchell SE; Kadir S; Williams GM; White RI Jr 《Radiology》1986,160(3):727-730
In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications. 相似文献
10.
Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance 总被引:3,自引:0,他引:3
Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy. 相似文献