全文获取类型
收费全文 | 3299749篇 |
免费 | 244287篇 |
国内免费 | 6781篇 |
专业分类
耳鼻咽喉 | 48029篇 |
儿科学 | 106652篇 |
妇产科学 | 94928篇 |
基础医学 | 469492篇 |
口腔科学 | 95925篇 |
临床医学 | 289586篇 |
内科学 | 640406篇 |
皮肤病学 | 74320篇 |
神经病学 | 264540篇 |
特种医学 | 127601篇 |
外国民族医学 | 1189篇 |
外科学 | 503845篇 |
综合类 | 75908篇 |
现状与发展 | 9篇 |
一般理论 | 1105篇 |
预防医学 | 249599篇 |
眼科学 | 78357篇 |
药学 | 245261篇 |
8篇 | |
中国医学 | 6960篇 |
肿瘤学 | 177097篇 |
出版年
2018年 | 32877篇 |
2016年 | 28453篇 |
2015年 | 32203篇 |
2014年 | 45254篇 |
2013年 | 68831篇 |
2012年 | 92208篇 |
2011年 | 98320篇 |
2010年 | 58352篇 |
2009年 | 55446篇 |
2008年 | 93091篇 |
2007年 | 100140篇 |
2006年 | 101441篇 |
2005年 | 98864篇 |
2004年 | 95228篇 |
2003年 | 91629篇 |
2002年 | 89925篇 |
2001年 | 151611篇 |
2000年 | 155704篇 |
1999年 | 131516篇 |
1998年 | 37504篇 |
1997年 | 33786篇 |
1996年 | 33333篇 |
1995年 | 31533篇 |
1994年 | 29316篇 |
1993年 | 27359篇 |
1992年 | 103240篇 |
1991年 | 100316篇 |
1990年 | 98219篇 |
1989年 | 95286篇 |
1988年 | 88298篇 |
1987年 | 86629篇 |
1986年 | 82538篇 |
1985年 | 78653篇 |
1984年 | 59442篇 |
1983年 | 50867篇 |
1982年 | 30631篇 |
1981年 | 27511篇 |
1979年 | 55579篇 |
1978年 | 39575篇 |
1977年 | 33840篇 |
1976年 | 31547篇 |
1975年 | 34602篇 |
1974年 | 41101篇 |
1973年 | 39879篇 |
1972年 | 37936篇 |
1971年 | 35095篇 |
1970年 | 33199篇 |
1969年 | 31690篇 |
1968年 | 29850篇 |
1967年 | 26377篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Dr. Arthur A. Dunk MRCP Natasha Kyprianou MSc Peter Davies PhD Howard C. Thomas PhD FRCP 《Digestive diseases and sciences》1988,33(4):472-476
Castrated or sham-operated male athymic mice were inoculated with cells from the human hepatocellular carcinoma cell line PLC/PRF/5. There were no significant differences between the two groups with respect to the number of animals developing tumors, the time to tumor development, or the subsequent rate of increase in either tumor base area or mouse serum alpha-fetoprotein concentration. Androgen receptors were assayed in nuclei obtained from three separate liver cancer cell lines and from normal adult human liver. Similar concentrations, ranging from 235 to 550 fmol/mg DNA, of nuclear androgen receptors were detected in all tissues. Low percentages of androgen receptors were retained on DNA-cellulose. Although the presence of receptors implies the potential for metabolic effects of androgens in normal and malignant liver, our in vivostudies suggest that castration does not alter significantly the growth of liver cancer xenografts in athymic mice. 相似文献
994.
995.
A surgical technique was used to establish chronic intestinal ulcers in Sprague-Dawley rats. A 2-cm-long segment of the distal ileum was excised and left attached on the mesentery. The ileum was reanastomosed. The excluded ileal segment formed a 'cyst' of various sizes. Initially, the anastomoses healed well, but after 6-8 weeks para-anastomotic ulcers developed in more than 50% of the rats. Histopathology showed a chronic inflammatory reaction with a predominance of mononuclear cells and increased numbers of eosinophilic granulocytes. The surface of the ulcers was covered with bacteria. Penetrating ulcers with fistula formation occurred. It is concluded that this experimental model may be useful for time sequential studies of the development of chronic and ulcerative ileitis. It may also be used to study the effect of medical and surgical regimens for the treatment of non-specific chronic inflammatory bowel disease. 相似文献
996.
P V Fragola C Autore G Ruscitti A Picelli M Borzi D Cannata M Sangiorgi 《Giornale italiano di cardiologia》1988,18(1):52-54
Eighty-nine first-degree relatives of 22 patients with an established diagnosis of hypertrophic cardiomyopathy underwent electrocardiographic and echocardiographic screening. Scalar electrocardiogram was abnormal in 30/89 (33.7%) relatives. Of these thirty, eleven had definite evidence of hypertrophic cardiomyopathy at echo; one had borderline hypertrophy and was considered neither affected nor unaffected; four had questionable signs of hypertrophy. The remaining 14 relatives had normal echo-cardiograms. Fifty-nine relatives (66.3%) had normal electrocardiograms; at echo 3 were considered to have borderline hypertrophy, 16 had questionable signs of hypertrophy and 40 were normal. In relatives of patients with hypertrophic cardiomyopathy an abnormal electrocardiogram may reflect different morphologic conditions: a real hypertrophic cardiomyopathy or a myocardial hypertrophy of uncertain significance. Furthermore, in these categories of subjects, an abnormal electrocardiogram with normal echo must be considered with caution. 相似文献
997.
Biological activity of partially purified digitalis-like substance and Na-K-ATPase inhibitor in rats
T Morise S Okamoto H Takasaki M Ikeda R Takeda F Kiuti Y Tuda 《Japanese circulation journal》1988,52(11):1309-1316
In order to study the biological activity of endogenous digitalis-like substance (DLS) and Na-K-ATPase inhibitor (ATPI), human urine was partially purified and administered to rats, and its effects on the urinary volume, urinary Na excretion and blood pressure (BP) were determined. In addition, the effect on myocardial Na-K-ATPase activity was also measured. After the extraction of 40L of urine with a reversed phase cartridge column (S-fraction), 20 ml of chloroform was added and extraction was repeated. The chloroform layer was applied to an open silica gel column, and at a fraction with ethylacetate: methanol (60: 40, T-1 fraction), DLS and ATPI were eluted at the highest concentration. The water layer was treated with charcoal (D-1 fraction). The acute administration of K-1, T-1 fraction to rats in vivo caused significant rises in urinary volume, urinary Na excretion and BP. In chronic administration of K-1 fraction, urinary Na excretion was significantly elevated and myocardial Na-K-ATPase activity was also significantly suppressed. These results suggest that DLS and ATPI cause increase in the urinary volume and urinary Na excretion and also possess a hypertensive action; and moreover, these substance may affect the heart like cardiotonic steroids and regulate BP by increasing cardiac contractility. 相似文献
998.
G N J Tytgat 《Acta chirurgica. Supplement》2002,(587):77-81
A true comparison of long-term medical and surgical treatment in gastro-oesophageal reflux disease (GORD) is impossible as few studies have been carried out with adequate randomisation of the patients and long-term evaluation of quality of life. In general the control of the reflux symptoms is roughly equal with medical and surgical treatment. However, surgery can cause other symptoms such as dysphagia or non-specific epigastric discomfort or pain in some patients, which reduces the overall efficacy in controlling the symptoms. Based on a cost utility analysis, Heudebert et al. came to the conclusion that medical treatment was their preferred strategy for most patients with severe erosive oesophagitis. 相似文献
999.
Gil Bolotin Frederik H. van der Veen Roberto Lorusso Tamir Wolf Robert Sachner Rona Shofti Jan J. Shreuder Gideon Uretzky 《European journal of cardio-thoracic surgery》2002,21(6):975-980
Objective: Descending and ascending aortomyoplasty are two surgical procedures intended to induce hemodynamic benefits similar to those of the intra-aortic-balloon-pump (IABP). To date, there have been no studies comparing the two surgical techniques. The objective of this study was to compare coronary blood flow augmentation and afterload reduction as produced by descending and ascending aortomyoplasty counterpulsation Methods: Twenty-two mongrel dogs (18–35 kg) underwent IABP application (n=7), descending (n=8), or ascending (n=7) aortomyoplasty. Left anterior descending (LAD) coronary artery blood flow was measured using a Transonic Doppler flow probe. Left ventricular pressure as well as aortic pressures proximal and distal to either the aortomyoplasty site or the IABP position were monitored continuously. Results: Descending aortomyoplasty induced higher elevation in the LAD blood flow during assisted beats (27% from 10.8±4 to 13.8±6 ml/min, P<0.001) than that induced by either ascending aortomyoplasty (19% from 11.7±5 to 14±5 ml/min, P<0.001) or IABP counterpulsation (18% from 8.6±3 to 10.2±4 ml/min, P<0.001). Conversely, while ascending aortomyoplasty reduced the left ventricular end-diastolic pressure by 16% (from 60±18 to 50±22 mmHg, P<0.001), similar to the 16% after load reduction achieved by the IABP counterpulsation, descending aortomyoplasty failed to induce afterload reduction. Conclusions: Descending aortomyoplasty produces higher coronary blood flow augmentation than either ascending aortomyoplasty or IABP. However, afterload reduction comparable to that achieved by IABP was observed only with ascending aortomyoplasty and not with descending aortomyoplasty. 相似文献
1000.
Cardiovascular calcification in end-stage renal disease. 总被引:13,自引:1,他引:12
Cardiovascular diseases are common in patients with end-stage renal disease (ESRD) and cardiovascular morbidity and mortality among dialysis patients are substantially higher than in the general population. The reasons for this high incidence are multiple. They include traditional factors such as hypertension, diabetes, dyslipidaemia, sodium overload, and elevated homocysteine levels as well as disturbances of mineral metabolism, specifically abnormalities in phosphorus and calcium homeostasis. This review will describe the specific cardiovascular complications related to calcifications in ESRD, the implications of the abnormalities of mineral metabolism in its pathogenesis and the current imaging techniques available for the detection of cardiovascular calcifications. Excess of calcium load contributes to the development of cardiac calcifications; therefore, alternative strategies to diminish exogenous calcium load should be considered in patients with ESRD. 相似文献