全文获取类型
收费全文 | 68900篇 |
免费 | 5714篇 |
国内免费 | 1770篇 |
专业分类
耳鼻咽喉 | 52篇 |
儿科学 | 3043篇 |
妇产科学 | 624篇 |
基础医学 | 4915篇 |
口腔科学 | 237篇 |
临床医学 | 9254篇 |
内科学 | 21420篇 |
皮肤病学 | 270篇 |
神经病学 | 1041篇 |
特种医学 | 1954篇 |
外科学 | 7278篇 |
综合类 | 12311篇 |
现状与发展 | 4篇 |
一般理论 | 3篇 |
预防医学 | 2985篇 |
眼科学 | 128篇 |
药学 | 6253篇 |
77篇 | |
中国医学 | 4006篇 |
肿瘤学 | 529篇 |
出版年
2024年 | 161篇 |
2023年 | 1111篇 |
2022年 | 1830篇 |
2021年 | 2736篇 |
2020年 | 3014篇 |
2019年 | 2674篇 |
2018年 | 2540篇 |
2017年 | 2408篇 |
2016年 | 2232篇 |
2015年 | 2264篇 |
2014年 | 4619篇 |
2013年 | 4844篇 |
2012年 | 3860篇 |
2011年 | 4144篇 |
2010年 | 3308篇 |
2009年 | 3140篇 |
2008年 | 3105篇 |
2007年 | 3293篇 |
2006年 | 2896篇 |
2005年 | 2696篇 |
2004年 | 2191篇 |
2003年 | 1985篇 |
2002年 | 1745篇 |
2001年 | 1566篇 |
2000年 | 1268篇 |
1999年 | 1273篇 |
1998年 | 1075篇 |
1997年 | 1020篇 |
1996年 | 802篇 |
1995年 | 768篇 |
1994年 | 766篇 |
1993年 | 576篇 |
1992年 | 567篇 |
1991年 | 493篇 |
1990年 | 396篇 |
1989年 | 369篇 |
1988年 | 320篇 |
1987年 | 295篇 |
1986年 | 278篇 |
1985年 | 313篇 |
1984年 | 263篇 |
1983年 | 155篇 |
1982年 | 190篇 |
1981年 | 163篇 |
1980年 | 136篇 |
1979年 | 115篇 |
1978年 | 103篇 |
1977年 | 82篇 |
1976年 | 75篇 |
1975年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
41.
Twenty-four patients treated with 150 mg amitriptyline per day for an episode of major depression underwent a standardized heart rate analysis (HRA) before therapy and after 14 days. The battery of cardiovascular reflex tests included the determination of the coefficient of variation (CV) while resting and during deep respiration, a spectral analysis of heart rate, the heart rate response to standing, and the Valsalva manoeuvre. The results of the initial HRA did not differ from a group of 24 normal control subjects matched for age and sex. On day 14 of treatment the patients showed significantly reduced values of heart rate variability in all tests (P<0.0001), probably due to the anticholinergic side effects of amitriptyline. Heart rate increased form 78.1 to 93.6 bpm on average (P<0.0001). Abnormal CV at rest was registered in 96% of the patients; during deep respiration 29% showed abnormal CV results. An abnormal spectral analysis was found in 100% of the cases (low frequency peak: 42%, mid-frequency peak: 100%, high frequency peak: 79%). The heart rate response to standing was abnormal in 75% and the Valsalva test in 33% of the cases. Eighty-eight percent of the patients fulfilled the criteria of a cardiovascular autonomic neuropathy under the conditions of amitriptyline therapy. As yet, the consequences of these changes for the patients have not been sufficiently elucidated. 相似文献
42.
In a cohort of 3383 men aged 53 to 74 in the Copenhagen Male Study we investigated the association between ischaemic heart disease (IHD) and the Lewis blood group, assigned to chromosome 19. Among men with the Le(a-b-) phenotype, 8% had a history of non-fatal myocardial infarction, among others the frequency was 4%. The corresponding odds ratio was (95% confidence interval: CI) 1.9 (1.2-3.0) P < 0.01, men with Le(a-b-) had a risk-factor profile and pattern of disease resembling that of Reaven's syndrome X. In a subsequent prospective study 343 men with arteriosclerotic stigmas were excluded. The men had their morbidity and mortality recorded over the next 4 years. One-hundred-and-one men suffered IHD; 26 dying from IHD. In total 162 men died. Men with Le(a-b-) had an increased risk of death from IHD compared with others. Adjusted for age, relative risk (RR) (95% CI) was: 4.4 (1.9-10.3), P < 0.001, and for all causes of mortality: RR = 1.6 (1.0-2.6), P < 0.05. Men with the Le(a-b-) phenotype had an increased risk of an IHD event compared to men with other phenotypes (RR = 1.6 (0.9-2.8), P = 0.10) and a significantly higher IHD case fatality rate (RR = 2.8 (1.5-5.2), P = 0.01). The finding that the Le(a-b-) phenotype is a genetic marker of IHD risk may have implications in terms of prevention. The Le(a-b-) phenotype may also contribute to providing an explanation for the substantial ethnic differences found in the incidence of IHD. The similar risk-factor profile and pattern of disease found between Le(a-b-) men and individuals with Reaven's syndrome X is hypothesized to be due to a close genetic relationship on chromosome 19. 相似文献
43.
分别采用联合火箭免疫电泳技术和酶法对49例冠心病患者和50例健康人血清载脂蛋白 A_1(apoA_1),载脂蛋白 B_(100)(apoB_(100)),以及血清总胆固醇(TC)、甘油三酯(TG),高密度脂蛋白胆固醇(HDL—ch)的含量进行了测定。结果冠心病患者血清 apoB_(100)(0.99±0.26g/L)明显高于健康人(0.62±0.18g/L);而apoA_1/apoB_(100)比值(1.22±0.35)则明显低于健康人(2.12±0.49);TC,TG,HDL-ch 的含量亦有统计学意义。提示,在预示冠心病危险因素的各种脂类及脂蛋白中,以 apoB_(100)增高 apoA_1/apoB_(100)比值降低最为灵敏,最为准确,且高于单纯测定TC,TG 和 HDL-ch。 相似文献
44.
Treatment of rat heart grafts with PUVA, the combination of the photosensitizer 8-methoxypsoralen and longwave ultraviolet light, leads to a prolonged transplant survival in allogeneic recipients. A PUVA treatment of the recipient rats, performed for 7 consecutive days after transplantation, prolonged graft survival even more effectively. This may be due to the systemic immunomodulatory effects of PUVA in the recipient. One of the mediators is urocanic acid, which is transformed by ultraviolet light in the skin from its trans- to the cis-isomer, which, in turn, acts as a mediator on the immune system. An injection of cisurocanic acid into graft recipients for 7 consecutive days after transplantation resulted in prolonged graft survival; in 40% of the rats, permanent graft acceptance was observed. The significance of these results for clinical organ transplantation is discussed. 相似文献
45.
46.
David Langton Diana Way Lisbeth Trigg Duncan Blake Barry McGrath 《Clinical and experimental pharmacology & physiology》1990,17(3):219-223
1. The effects of graded treadmill exercise on renal blood flow (RBF) were examined in seven rabbits, in which congestive heart failure (CHF) was produced by the administration of doxorubicin, 1 mg/kg, twice weekly for 8 weeks, and in seven controls. A third group of five rabbits underwent doxorubicin treatment with the addition of surgical section of the left renal sympathetic nerve. 2. During submaximal exercise, there was a small reduction in RBF in controls, which was greatly exaggerated in CHF. 3. In both control and heart failure rabbits, there was a precipitous fall in RBF as exercise fatigue developed. 4. Renal sympathectomy ablated these changes in RBF during exercise. 5. It is concluded that in heart failure there is an exaggerated, sympathetically mediated, diversion of blood flow away from the kidney. The onset of exercise fatigue in both normal and heart failure rabbits is accompanied by a marked intensification of this process. 相似文献
47.
在海拔3417m对18名健康世居藏族和16名移居汉族用Jeager气体代谢自动分析系统和心阴抗图测定了无氧阈和最大摄氧量时的SV、CO、PEP/LVET和SaO2。结果显示:在海拔3417m测得AT值明显低于海平面;世居藏族AT出现较晚,并且AT时的功率、VO2、MV、HR、CO、SV均高于移居汉族,而PET/LVET比值小于移居组;两组的SV峰值出现时间不同,蕊居组在AT或AT以后出现的占72% 相似文献
48.
Risk factors for coronary heart disease among inpatients who have mild intellectual disability and mental illness 总被引:1,自引:1,他引:0
S. Merriman C. Haw J. Kirk & J. Stubbs 《Journal of intellectual disability research : JIDR》2005,49(5):309-316
Background Coronary heart disease (CHD) is a major cause of morbidity and mortality in the UK. The aim of this study was to screen inpatients with mild or borderline intellectual disability, many of whom also have mental illness, for risk factors for CHD. Methods Cross sectional survey. Participants were interviewed, measured and had blood samples taken. Results Of the 53 participants, 20 (37.7%) were overweight and 18 (34.0%) obese. The mean body mass index (BMI) of those participants prescribed regular antipsychotics was higher than those who were not. Nine (20.9%) had waist circumference measurements placing them at increased risk of CHD and 21 (48.8%) were at substantially increased risk. Twenty-eight (52.8%) were current smokers. Of the 49 participants who had their blood pressure measured, 3 (6.1%) had readings above the reference range. Of the 19 participants who had random blood tests, one (5.3%) had an elevated cholesterol level. Conclusions In this population there was a high prevalence of two risk factors for CHD (obesity and smoking), requiring ongoing monitoring and long-term measures to reduce risk. 相似文献
49.
50.
①目的 了解猪同种原位心脏移植术后早期一氧化氮 (NO)、一氧化氮合酶 (NOS)含量的变化 ,及其与早期缺血再灌注损伤的关系。②方法 建立猪同种原位心脏移植模型。供心在移植前低温保存 (Thomas液 ,4℃ ) 4h ,移植成功心脏复搏后 2h取材。应用组织化学方法测定心肌组织中NO、NOS的含量 ,应用核酸原位末端标记法 (TUNEL)测定心肌细胞凋亡指数 ,作为评价心肌缺血再灌注损伤的指标。以正常心肌及单纯缺血心肌组织作为对照。③结果 移植后心肌组织NO、NOS的含量较缺血组与正常组低 ,差异有显著意义 (F =2 7.2 2 9、16 .2 0 3,q =5 .716~ 6 .4 12 ,P <0 .0 1)。移植组心肌细胞凋亡指数与正常组及缺血组比较明显升高 ,差异有显著性(F =16 3.884 ,q =7.4 82、6 .975 ,P <0 .0 1)。心肌组织NO、NOS含量与心肌细胞凋亡指数呈负相关关系 (r =- 0 .886、- 0 .795 ,P <0 .0 1)。④结论 猪心脏移植后早期心肌缺血再灌注损伤所致的细胞死亡主要表现为心肌细胞凋亡 ;再灌注期间内源性NO、NOS的减少参与了心脏移植后早期缺血再灌注损伤的发生 相似文献