全文获取类型
收费全文 | 2470331篇 |
免费 | 178976篇 |
国内免费 | 3825篇 |
专业分类
耳鼻咽喉 | 33459篇 |
儿科学 | 78922篇 |
妇产科学 | 64712篇 |
基础医学 | 363930篇 |
口腔科学 | 66517篇 |
临床医学 | 223489篇 |
内科学 | 481973篇 |
皮肤病学 | 54304篇 |
神经病学 | 196687篇 |
特种医学 | 93378篇 |
外国民族医学 | 500篇 |
外科学 | 372463篇 |
综合类 | 48985篇 |
现状与发展 | 12篇 |
一般理论 | 937篇 |
预防医学 | 191738篇 |
眼科学 | 56845篇 |
药学 | 182846篇 |
11篇 | |
中国医学 | 4773篇 |
肿瘤学 | 136651篇 |
出版年
2021年 | 21534篇 |
2019年 | 21896篇 |
2018年 | 29800篇 |
2017年 | 22494篇 |
2016年 | 25162篇 |
2015年 | 28335篇 |
2014年 | 39861篇 |
2013年 | 59271篇 |
2012年 | 82509篇 |
2011年 | 87739篇 |
2010年 | 51961篇 |
2009年 | 49194篇 |
2008年 | 82099篇 |
2007年 | 87270篇 |
2006年 | 88028篇 |
2005年 | 85497篇 |
2004年 | 81455篇 |
2003年 | 78257篇 |
2002年 | 75668篇 |
2001年 | 110183篇 |
2000年 | 112638篇 |
1999年 | 94953篇 |
1998年 | 28408篇 |
1997年 | 24818篇 |
1996年 | 25047篇 |
1995年 | 23652篇 |
1994年 | 21710篇 |
1993年 | 20473篇 |
1992年 | 72885篇 |
1991年 | 70874篇 |
1990年 | 69098篇 |
1989年 | 66313篇 |
1988年 | 60950篇 |
1987年 | 59701篇 |
1986年 | 55835篇 |
1985年 | 53617篇 |
1984年 | 39957篇 |
1983年 | 33985篇 |
1982年 | 20560篇 |
1979年 | 36333篇 |
1978年 | 26124篇 |
1977年 | 21630篇 |
1976年 | 20711篇 |
1975年 | 22138篇 |
1974年 | 26522篇 |
1973年 | 25136篇 |
1972年 | 23509篇 |
1971年 | 22270篇 |
1970年 | 20475篇 |
1969年 | 19488篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The purpose of this study was to evaluate a new fluorescence polarization immunoassay, TDx, for digitoxin by comparing the results of this assay with those of a radioimmunoassay (RIA). Thirty-three serum samples were obtained from 15 patients during, and for 4 weeks after, a 4-week course of digitoxin therapy. Each sample was separated by centrifugation, coded, and frozen until analysis. At the time of analysis, each sample was divided and analyzed simultaneously by TDx and RIA. Nine samples yielded results less than 2 ng/ml (limit of assay sensitivity) by one or both methods and were excluded from further data analysis. Linear regression analysis of the results of the remaining 24 paired samples (x = TDx, y = RIA) revealed a strong correlation coefficient of r2 = 0.95, slope = 0.95, and a y intercept of -0.99 (y = -0.99 + 0.95x). Additionally, the TDx results were lower than the RIA values in only five of 33 paired samples; and these occurred in four patients who had a significantly lower mean estimated creatinine clearance than that of the other 11 patients (39.0 +/- 9.1 ml/min/1.73 m2 vs. 63.3 +/- 11.8 ml/min/1.73 m2, p less than 0.01). The TDx system is a comparable alternative to the RIA method, but differences in specificity and sensitivity may exist and should be evaluated more thoroughly. 相似文献
992.
993.
Trends in analgesic self-poisoning in West-Fife, 1971-1985 总被引:1,自引:0,他引:1
J J McMurray D B Northridge V A Abernethy A A Lawson 《The Quarterly journal of medicine》1987,65(246):835-843
All admissions for analgesic self-poisoning to a district poisons unit over a 15-year period have been reviewed. During this time overdose with analgesic drugs increased to represent almost half of all admissions for self-poisoning. The types of analgesics taken in overdose also changed significantly during the period of this review. Aspirin and Distalgesic poisoning declined in incidence and more cases of self-poisoning by paracetamol and non-steroidal anti-inflammatory agents were seen. The impact of these changes on the medical management and outcome of deliberate self-poisoning is analysed. The reasons behind the trends described in this paper are assessed and their implications for future prevention and treatment are discussed. 相似文献
994.
995.
996.
Thomas J Birk Rodger D MacArthur Lynn M Lipton Sheldon D Levine 《The Journal of the Association of Nurses in AIDS Care》2002,13(6):20-24
The purpose of this study was to determine whether blood lipid and lipoprotein concentrations varied in 5 men with advanced HIV-1 infection after 12 months of aerobic exercise training. Prior to exercise, the mean baseline cholesterol and high-density lipoprotein cholesterol (HDL-C) serum concentration were each lower, and mean baseline triglyceride concentration was higher compared to a healthy population norm. Consistent exercise training for 12 months failed to significantly (p > .05) alter cholesterol or HDL-C. Triglyceride concentration was significantly (p < .05) elevated above baseline (63 mg/dL) regardless of exercise compliance. The results suggest that long-term exercise training cannot correct lipid profile abnormality, particularly hypertriglyceridemia, common to individuals with advanced HIV-1 infection. 相似文献
997.
998.
Cardiovascular function was studied in anaesthetised male rats which received 50 micrograms/ml of arsenic (as sodium arsenate) in deionised drinking water for 320 days. High urinary excretion of arsenic was found at the end of treatment and the metal accumulated considerably in the kidneys and liver, which both presented slight alterations. No histopathological modifications were evident in other organs. Base line blood pressure, cardiac inotropism, and chronotropism and cardiovascular reactivity to noradrenaline, acetylcholine, angiotensin II, bradykinin, histamine, and serotonin did not differ in exposed or in control animals. In the exposed group, however, there was potentiation of the effects of vascular beta-adrenoceptor stimulation and a reduction in the vascular responsiveness to angiotensin I. Chronic arsenic exposure did not affect the baroreflex sensitivity but was able to induce sympathetic hyperactivity or hypersensitivity, or both, possibly associated with an antivagal action. Our results might help to explain the cardiovascular alterations seen in people chronically exposed to high concentrations of arsenic. 相似文献
999.
1000.
A Messineo R M Filler B Bahoric C Smith A Bahoric 《Journal of pediatric surgery》1991,26(11):1296-1300
A major problem in tracheal transplantation is the restoration of an adequate vascular supply to the transplanted trachea. In 12 piglets, a segment (6 rings) of thoracic trachea was removed and the excised segment was then sutured back in place. In 9 animals (group A), a vascularized omental flap was wrapped around the autotransplanted trachea. In the other 3 pigs (group B), the omentum was not used. Eight of 9 group A pigs were killed, 1 or 2 months later, having had no signs of airway obstruction; the 9th pig was killed after 14 days because of airway obstruction. The 3 pigs in group B were killed after 11 to 13 days because of progressive respiratory obstruction. In the 8 asymptomatic pigs in group A, the omental flap was viable and tracheal growth was normal with no differences in diameter between normal and autotransplanted trachea. Histologically intact cartilage was lined with respiratory epithelium. In the one group A pig who was killed early, the omental flap was necrotic. In this pig and in the 3 group B animals, extensive tracheal necrosis and nonviable cartilage were observed. These findings indicate that in the pig, a 6-ring segment of trachea can be transplanted with vascularization provided by an omental flap. 相似文献