全文获取类型
收费全文 | 2361篇 |
免费 | 73篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 92篇 |
妇产科学 | 43篇 |
基础医学 | 202篇 |
口腔科学 | 31篇 |
临床医学 | 151篇 |
内科学 | 686篇 |
皮肤病学 | 37篇 |
神经病学 | 127篇 |
特种医学 | 30篇 |
外科学 | 349篇 |
综合类 | 100篇 |
预防医学 | 323篇 |
眼科学 | 44篇 |
药学 | 129篇 |
中国医学 | 10篇 |
肿瘤学 | 80篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 31篇 |
2021年 | 52篇 |
2020年 | 36篇 |
2019年 | 268篇 |
2018年 | 212篇 |
2017年 | 81篇 |
2016年 | 20篇 |
2015年 | 27篇 |
2014年 | 43篇 |
2013年 | 50篇 |
2012年 | 46篇 |
2011年 | 53篇 |
2010年 | 34篇 |
2009年 | 37篇 |
2008年 | 37篇 |
2007年 | 32篇 |
2006年 | 31篇 |
2005年 | 22篇 |
2004年 | 17篇 |
2003年 | 14篇 |
2002年 | 10篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 10篇 |
1997年 | 6篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 108篇 |
1984年 | 167篇 |
1983年 | 124篇 |
1982年 | 144篇 |
1981年 | 119篇 |
1980年 | 107篇 |
1979年 | 100篇 |
1978年 | 77篇 |
1977年 | 49篇 |
1976年 | 62篇 |
1975年 | 60篇 |
1974年 | 49篇 |
1973年 | 42篇 |
1972年 | 7篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有2438条查询结果,搜索用时 46 毫秒
81.
Rats with or without 0.5% tolbutamide in the diet were injected over a 5-day period with growth hormone, ACTH, cortisol, dexamethasone, or various mixtures of these diabetogenic hormones and the daily alterations in blood glucose (BG), serum (SI), and pancreatic insulin (PI) concentrations followed as well as glucosuria. GH (5 mg/day) increased the insulin concentration in the pancreas and serum without affecting blood glucose. ACTH (80 IU/day) decreased PI and increased SI with only a slight increase in BG. Cortisol and dexamethasone decreased PI and increased SI and BG. The severalfold increase in SI with glucocorticoids always preceded the increase in BG by 12–24 hr. Mixtures of GH with the glucocorticoids increased and quickened the rise in BG and SI and the falls in PI, but the rise in SI always preceded the rise in BG by several hours. During multiple hormonal treatment, PI decreased in magnitude usually for 3–4 days but by the fifth day tended to revert toward normal, showing adaptation. In contrast, BG and SI tended to remain elevated and glucosuria persisted. These data suggest that in spite of the high concentrations of diabetogenic agents used compensatory changes were made by the rat with intact pancreas over a period of 5 or more days. This hormonally induced condition of elevated SI and BG but normal PI is characteristic of insulin resistance. Tolbutamide by itself decreased PI without a rise in SI (except for a temporary increase at 4–8 hr after the first injection) and with only a minor decrease in BG. Most of the changes due to the hormones were accentuated in rats with 0.5% tolbutamide in the diet, suggesting that tolbutamide is diabetogenic because it decreases PI. 相似文献
82.
Takahisa Uchiyama Eliot Corday Samuel Meerbaum Tzu-Wang Lang Pascal Gueret Moysey Povzhitkov Thomas Peter 《The American journal of cardiology》1981,48(4):679-689
Two dimensional echocardiography was applied experimentally in the closed chest dog to quantitate left ventricular function during and immediately after single premature ventricular contractions induced through threshold stimulation at the apex. Coupling intervals were varied over a range from 35 to 85 percent of the R-R interval during normal sinus rhythm (920 to 980 ms). The quality of tomographic echocardiographic images during premature as well as postextrasystolic beats was found to be satisfactory for quantitating short axis section areas at end-diastole and end-systole. A systolic fractional area change was computed from two dimensional echocardiographic measurements to characterize mid ventricular cardiac function, which correlated significantly with peak left ventricular pressure and maximal first derivative of left ventricular pressure (dP/dt). Marked shortening of coupling intervals reduced fractional shortening during premature systole and enhanced the degree of potentiation during the postextrasystolic beat. By contrast, premature beats with relatively long coupling intervals caused less reduction in contraction and only minor postextrasystolic potentiation.Systolic shortening of left ventricular length as well as transverse diameters were studied in a two dimensional echocardiographic long axis cross section. During long coupling intervals contraction was normal except for distinct regional systolic outward “bulging” in the apical region. In contrast, short coupling intervals were associated with a more significant generalized derangement of ventricular wall motion during systole. It is concluded that the two dimensional echocardiographic method can be used to portray and quantitate global as well as regional left ventricular function during disturbances of cardiac rhythm. 相似文献
83.
In the past 10 years, there has been substantial progress in the treatment of patients with acute myelogenous leukemia. Intensive induction chemotherapy and consolidation chemotherapy have increased complete remission rates from 25 percent to more than 70 percent and have extended median survival from six months to more than two years. Attempts to prolong remission with maintenance chemotherapy, immunotherapy, and central nervous system prophylaxis have been less successful. Recent data suggest that the use of intensification chemotherapy or bone marrow transplantation in patients in remission may further reduce or eliminate residual leukemia. As a result of one or more of these advances an increasing proportion of patients, up to 25 percent in some series, are alive and free of disease three to five years following diagnosis. Most data indicate that some of these patients may be cured. In this article, we review the therapeutic interventions responsible for this substantial increase in survival in what was previously a uniformly fatal disease. Recent advances are discussed as are controversies in management and future directions. 相似文献
84.
Radiation heart disease. Analysis of 16 young (aged 15 to 33 years) necropsy patients who received over 3,500 rads to the heart 总被引:3,自引:0,他引:3
Certain clinical and necropsy findings are described in 16 young (aged 15 to 33 years) patients who received greater than 3,500 rads to the heart five to 144 months before death. All 16 had some radiation-induced damage to the heart: 15 had thickened pericardia (five of whom had evidence of cardiac tamponade); eight had increased interstitial myocardial fibrosis, particularly in the right ventricle; 12 had fibrous thickening of the mural endocardium and 13 of the valvular endocardium. Except for valvular thickening, the changes were more frequent in the right side of the heart than in the left, presumably because of higher radiation doses to the anterior surface of the heart. In six of the 16 study patients and in one of 10 control subjects, one or more major epicardial coronary arteries were narrowed from 76 to 100 percent in cross-sectional area by atherosclerotic plaque; one patient had a healed myocardial infarct at necropsy and one died suddenly. In 10 patients and in the 10 control subjects, the four major epicardial coronary arteries were examined quantitatively: 6 percent of the 469 five millimeter segments of coronary artery from the patients were narrowed from 76 to 100 percent (controls = 0.2 percent, p = 0.06) and 22 percent were narrowed from 51 to 75 percent (controls = 12 percent). The proximal portion of the arteries in the patients had significantly more narrowing than the distal portions. The arterial plaques in the patients were largely composed of fibrous tissue; the media were frequently replaced by fibrous tissue, and the adventitia were often densely thickened by fibrous tissue. In five patients, there was focal thickening (with or without luminal narrowing) of the intramural coronary arteries. Thus, radiation to the heart may produce a wide spectrum of functional and anatomic changes but particularly damage to the pericardia and the underlying epicardial coronary arteries. 相似文献
85.
The effect of central nervous system prophylaxis (cranial radiation and intrathecal chemotherapy) on intellectual function was studied in 24 children with acute lymphocytic leukemia. The Wechsler Intelligence tests were administered to these children and to a sample of their healthy siblings, who served as a comparison group. The mean Full Scale IQ was 98.6 for the patients and 112.5 for the sibling controls (p < 0.001 level). Those patients who received central nervous system preventive treatment at a young age exhibited a greater decrement in intellectual abilities than did patients who were older when they received this treatment. In contrast, leukemia patients who had not received central nervous system prophylaxis had IQs that did not differ statistically from those of their siblings. These data suggest that central nervous system prophylaxis may have an adverse effect on the intellectual capability of children with acute lymphocytic leukemia. 相似文献
86.
宁波市医疗中心李惠利医院于2013年通过招募院内外的志愿者组建了“惠民利民”志愿服务队,根据专业特长及病人需要分成了四个组,进行针对性培训,在不同的区域分别开展志愿服务。通过8个月的志愿服务,弥补了医院管理、医院制度和医疗活动中的不足,降低了投诉率,促进医患和谐。本文结合医院实际工作介绍了志愿者服务队的建立、培训、管理的经验和效果,具有现实的指导意义。 相似文献
87.
88.
89.
Marie T. Fluent Jack L. Ferracane James G. Mace Anjali R. Shah Richard B. Price 《Journal of the American Dental Association (1939)》2019,150(12):1051-1058
BackgroundDental light-curing units (LCUs) are powerful sources of blue light that can cause soft-tissue burns and ocular damage. Although most ophthalmic research on the hazards of blue light pertains to low levels from personal electronic devices, computer monitors, and light-emitting diode light sources, the amount of blue light emitted from dental LCUs is much greater and may pose a “blue light hazard.”MethodsThe authors explain the potential risks of using dental LCUs, identify the agencies that provide guidelines designed to protect all workers from excessive exposure to blue light, discuss the selection of appropriate eye protection, and provide clinical tips to ensure eye safety when using LCUs.ResultsWhile current literature and regulatory standards regarding the safety of blue light is primarily based on animal studies, sufficient evidence exists to suggest that appropriate precautions should be taken when using dental curing lights. The authors found it difficult to find on the U.S. Food and Drug Administration database which curing lights had been cleared for use in the United States or Europe and could find no database that listed which brands of eyewear designed to protect against the blue light has been cleared for use. The authors conclude that more research is needed on the cumulative exposure to blue light in humans. Manufacturers of curing lights, government and regulatory agencies, employers, and dental personnel should collaborate to determine ocular risks from blue light exist in the dental setting, and recommend appropriate eye protection. Guidance on selection and proper use of eye protection should be readily accessible.Conclusions and Practical ImplicationsThe Centers for Disease Control and Prevention Guidelines for Infection Control in the Dental Health-Care Setting–2003 and the Occupational Safety and Health Administration Bloodborne Pathogen Standard do not include safety recommendations or regulations that are directly related to blue light exposure. However, there are additional Occupational Safety and Health Administration regulations that require employers to protect their employees from potentially injurious light radiation. Unfortunately, it is not readily evident that these regulations apply to the excessive exposure to blue light. Consequently employers and dental personnel may be unaware that these Occupational Safety and Health Administration regulations exist. 相似文献
90.