全文获取类型
收费全文 | 4361543篇 |
免费 | 339860篇 |
国内免费 | 14797篇 |
专业分类
耳鼻咽喉 | 60340篇 |
儿科学 | 139552篇 |
妇产科学 | 114225篇 |
基础医学 | 667166篇 |
口腔科学 | 118106篇 |
临床医学 | 397509篇 |
内科学 | 791258篇 |
皮肤病学 | 107806篇 |
神经病学 | 368871篇 |
特种医学 | 169820篇 |
外国民族医学 | 753篇 |
外科学 | 656825篇 |
综合类 | 121312篇 |
现状与发展 | 24篇 |
一般理论 | 2616篇 |
预防医学 | 360559篇 |
眼科学 | 100987篇 |
药学 | 307832篇 |
26篇 | |
中国医学 | 11941篇 |
肿瘤学 | 218672篇 |
出版年
2021年 | 56308篇 |
2020年 | 35916篇 |
2019年 | 58898篇 |
2018年 | 74473篇 |
2017年 | 57077篇 |
2016年 | 63249篇 |
2015年 | 76166篇 |
2014年 | 110426篇 |
2013年 | 175985篇 |
2012年 | 124714篇 |
2011年 | 129455篇 |
2010年 | 126061篇 |
2009年 | 127765篇 |
2008年 | 115527篇 |
2007年 | 122825篇 |
2006年 | 131540篇 |
2005年 | 125517篇 |
2004年 | 126830篇 |
2003年 | 117015篇 |
2002年 | 106262篇 |
2001年 | 166979篇 |
2000年 | 162049篇 |
1999年 | 148693篇 |
1998年 | 71691篇 |
1997年 | 67633篇 |
1996年 | 65637篇 |
1995年 | 61066篇 |
1994年 | 54981篇 |
1993年 | 51026篇 |
1992年 | 106638篇 |
1991年 | 101398篇 |
1990年 | 97263篇 |
1989年 | 94831篇 |
1988年 | 87158篇 |
1987年 | 85322篇 |
1986年 | 80203篇 |
1985年 | 78361篇 |
1984年 | 65401篇 |
1983年 | 58204篇 |
1982年 | 47199篇 |
1981年 | 43860篇 |
1980年 | 41078篇 |
1979年 | 55104篇 |
1978年 | 44758篇 |
1977年 | 39978篇 |
1976年 | 36847篇 |
1975年 | 36806篇 |
1974年 | 39613篇 |
1973年 | 37758篇 |
1972年 | 35365篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Aim : The study was designed to determine the effect of computerized nutrition information on consumer food choice in two workplace restaurants, one in which customers had to pay for their lunch and the other providing a free lunch. Methods : Customers entering the restaurants were asked to make selections from the menu on a computer screen. The energy, saturated fatty acids, non-milk extrinsic sugars and non-starch polysaccharide content of the meal selected was displayed graphically in proportion to the dietary reference values. They were given the opportunity to change their selected meal and the composition of all meals was recorded. Results : The nutritional composition of the first meal provoked 16% of customers to make a second selection. The proportion of energy in the first selection had been 31% higher for saturated fatty acids and 23% higher for non-milk extrinsic sugars than the first selection made by people who were satisfied with their first choice. In their second attempt they succeeded in reducing both nutrients to levels similar to those present in the meals selected by people who had been satisfied with their first selection. Customers>> selections for non-starch polysaccharide and energy did not differ between the groups. The main changes made by customers to achieve improved second choices were to omit dishes (44%), add dishes (19%), make changes within a menu category (46%), and make changes from one menu category to another (26%). Conclusion : It was concluded that provision of graphical nutrition information on a computer screen could be used by a subset of the users of both restaurants to enable them to improve their menu selections to a similar composition to that selected by the other people who used the computer system. 相似文献
992.
W. F. S. Sellers 《Anaesthesia》1996,51(5):513-513
993.
为研究包钢的原料中所含天然钍对作业工人健康的影响,对5985人的暴露队列进行了17年的流行病学调查。结果发现,作业工人外周血淋巴细胞染色体畸变率随年附加有效剂量的增加而升高(与对照组比较P<0.01)。工龄为5~14年者增加较快,15年后增加缓慢,趋于平衡。尘肺分析结果提示,天然钍可能增强SiO2的致肺纤维化作用。肿瘤死亡率除胃癌外,其余RR均大于1,但无统计学意义。相距一年的两次植物血球凝集素(PHA)皮试反应均有增强,但外周血淋巴细胞离体照射后,染色体畸变未见适应性。女工妊娠期从事钍作业,其所生子女的智力发育无明显异常。 相似文献
994.
A RELIABLE MARKER OF ENDOTHELIAL CELL DYSFUNCTION: DOES IT EXIST? 总被引:19,自引:0,他引:19
995.
996.
S. Süreyya
zbek Remide Arkun Refik Killi Ayenur Memi Aynur Dadeviren Erkan Sevin 《Journal of clinical ultrasound : JCU》1995,23(4):233-238
Image-directed color Doppler ultrasonography (ICDUS) studies of 86 patients with superficial solid masses yielded significantly lower resistive index (RI) values in acute inflammatory lesions, but no significant difference between the maximum systolic flow velocities (S) of the patient groups with malignant, benign, and acute inflammatory lesions. When analyzed separately, the malignant soft-tissue tumor subgroup was shown to have significantly higher mean RI compared to that of the malignant node subgroup. We conclude that RI may be useful in the differentiation of acute inflammatory masses from other pathological entities. Malignant soft-tissue tumors, especially sarcomas, may have different Doppler features from those of carcinomatous tumors. © 1995 John Wiley & Sons, Inc. 相似文献
997.
998.
Ch. Lenzen N. Roewer F. Wappler A. Köchling M. Steinfath J. Sgholz J. Schulte am Esch 《Acta anaesthesiologica Scandinavica》1995,39(3):343-346
Dantrolene seems to be the causal therapy in malignant hyperthermia (MH) crisis but the complex mechanisms of MH and dantrolene therapy are still not fully understood. The influence of dantrolene on ryanodine-induced contractures has been reported in animal studies only. In the present study 20 patients from] 7 families were tested for MH using the protocol of the European Malignant Hyperthermia Group. In addition ryanodine-induced contractures were evaluated following bolus application of 10.0 μmol · 1-1 ryanodine. After pretreatment with 1 μimol · 1-1 dantrolene ryanodine-provoked contractures developed significantly later in MHS (15.8±1.8 min) and MHN (46.0±4.2 min) muscle specimens than after ryanodine alone (MHS 4.8±0.7 min), (MHN 13.7±0.9 min). They were no longer observed in either group after pretreatment with 5 μimol · 1-1 dantrolene. We conclude that dantrolene is able to attenuate ryanodine-induced contractures dose-dependendy, and therefore it is speculated that dantrolene could specifically act at the ryanodine receptor binding site. 相似文献
999.
Kevin L. Greason M.D. Jose A. Acosta M.D. Thomas J. Magrino M.D. Moogil Choe M.D. 《Diseases of the colon and rectum》1996,39(6):702-704
PURPOSE: This study was undertaken to clarify the importance of bleeding vascular ectasia of the colon as the etiology of massive lower gastrointestinal hemorrhage in patients 40 years of age or younger. METHODS: An otherwise healthy 21-year-old male was admitted to a tertiary medical center with massive lower gastrointestinal hemorrhage. Technetium-labeled red blood cell scan, selective visceral angiography, and colonoscopy identified the source of bleeding as vascular abnormality of the descending colon. Segmental colonic resection was performed. RESULTS: Histologic review of the specimen demonstrated a vascular ectasia. The patient recovered uneventfully and has had no further stigmata of hemorrhage. A review of the literature was undertaken to make clear the significance of vascular ectasia as the source for massive colonic hemorrhage in the young adult. CONCLUSION: This is the first report that documents histologically a vascular ectasia as the source of massive lower gastrointestinal hemorrhage in an otherwise healthy patient less than 40 years of age. Vascular ectasia is an uncommon cause of lower gastrointestinal hemorrhage in the young adult.The Chief, Bureau of Medicine and Surgery, Navy Department, Washington, DC, Clinical Investigation Program sponsored this report #84-16-1968-532, as required by HSETCINST 6000.41A. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. 相似文献
1000.