全文获取类型
收费全文 | 55222篇 |
免费 | 4809篇 |
国内免费 | 1167篇 |
专业分类
耳鼻咽喉 | 289篇 |
儿科学 | 1147篇 |
妇产科学 | 1420篇 |
基础医学 | 4765篇 |
口腔科学 | 883篇 |
临床医学 | 5654篇 |
内科学 | 7890篇 |
皮肤病学 | 461篇 |
神经病学 | 2045篇 |
特种医学 | 3262篇 |
外国民族医学 | 18篇 |
外科学 | 3998篇 |
综合类 | 8192篇 |
现状与发展 | 3篇 |
预防医学 | 8365篇 |
眼科学 | 360篇 |
药学 | 7089篇 |
122篇 | |
中国医学 | 1981篇 |
肿瘤学 | 3254篇 |
出版年
2024年 | 129篇 |
2023年 | 814篇 |
2022年 | 1584篇 |
2021年 | 2267篇 |
2020年 | 2167篇 |
2019年 | 1873篇 |
2018年 | 1993篇 |
2017年 | 1922篇 |
2016年 | 2018篇 |
2015年 | 1884篇 |
2014年 | 3802篇 |
2013年 | 3999篇 |
2012年 | 3456篇 |
2011年 | 3695篇 |
2010年 | 2802篇 |
2009年 | 2547篇 |
2008年 | 2512篇 |
2007年 | 2577篇 |
2006年 | 2090篇 |
2005年 | 1851篇 |
2004年 | 1606篇 |
2003年 | 1342篇 |
2002年 | 1226篇 |
2001年 | 1064篇 |
2000年 | 931篇 |
1999年 | 868篇 |
1998年 | 697篇 |
1997年 | 703篇 |
1996年 | 648篇 |
1995年 | 581篇 |
1994年 | 571篇 |
1993年 | 446篇 |
1992年 | 453篇 |
1991年 | 422篇 |
1990年 | 354篇 |
1989年 | 360篇 |
1988年 | 302篇 |
1987年 | 251篇 |
1986年 | 238篇 |
1985年 | 315篇 |
1984年 | 266篇 |
1983年 | 161篇 |
1982年 | 224篇 |
1981年 | 190篇 |
1980年 | 168篇 |
1979年 | 156篇 |
1978年 | 105篇 |
1977年 | 109篇 |
1976年 | 95篇 |
1975年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Sung Hee Chung Olof Heimbürger Bengt Lindholm Hi Bahl Lee 《Nephrology, dialysis, transplantation》2005,20(6):1207-1213
BACKGROUND: Dialysis patient mortality remains high, and this high mortality may be due to many factors. In peritoneal dialysis (PD) patients, old age, co-morbid diseases, malnutrition, low residual renal function (RRF) and a high peritoneal transport rate have been shown to influence survival, but the relative importance of these factors may differ between different patient populations. Besides, centre practice patterns may differ between centres and may influence patient survival. In addition, the literature suggests that dialysis patient survival may be better in Asian than in Caucasian patients. METHODS: The influence of centre and patient characteristics on patient survival was investigated in 132 Korean and 106 Swedish incident PD patients, who underwent initial biochemical measurements and assessment of adequacy of dialysis, nutritional status, RRF and peritoneal transport characteristics. RESULTS: At the start of PD, Korean patients had a higher prevalence of diabetes, peritoneal Kt/V(urea), peritoneal creatinine clearance and peritoneal fluid removal, and lower body mass index, RRF and dialysate to plasma creatinine concentration ratio (D/P Cr) compared with Swedish patients. Significantly more patients from Korea were placed on temporary haemodialysis before PD (100 out of 132) when compared with Swedish patients (21 out of 106). During the follow-up, there was a significantly higher rate of transfer to other units in Korea and a significantly higher rate of kidney transplantation in Sweden. On Kaplan-Meier analysis, overall patient survival did not differ and relative risk for death was also not different between the two centres even after adjustment for age, diabetes, cardiovascular disease, RRF and D/P Cr. On Cox proportional hazards multivariate analysis, age, diabetes, RRF and D/P Cr were found to be independent predictors of mortality in the combined cohort of patients. While age, diabetes and D/P Cr were independent predictors of mortality in Korean patients, age and RRF independently predicted mortality in Swedish patients. CONCLUSION: Although there were significant differences in centre and patient characteristics, we were unable to confirm a survival advantage for Korean over Swedish PD patients. The results of this study suggest that the reported difference in survival between Asian and Caucasian dialysis patients may have been due, in part, to differences in centre and patient characteristics rather than to race as such. The genetic influence on patient characteristics remains, however, to be elucidated. 相似文献
22.
不同采血针对新生儿足跟采血成功率的影响 总被引:1,自引:0,他引:1
黄敦年 《安徽卫生职业技术学院学报》2009,8(5):103-103,108
目的:探讨不同采血针在新生儿疾病筛查采血中的采血效果。方法:采用三种采血针分别对2126例(A组)、1786例(B组)、1471例(C组)新生儿进行足跟采血,比较其采血成功率。结果:A、B、C三组之间差异有统计学意义(P〈0.01)。结论:采用7号一次性注射针头采血(C组)可明显提高采血成功率。 相似文献
23.
Christos Varounis Nikolaos Dagres Themistoclis Maounis Demosthenes Panagiotakos Dennis V Cokkinos 《Europace : European pacing, arrhythmias, and cardiac electrophysiology》2007,9(8):633-637
AIMS: The aim of this study was to investigate the significance of simple 24-h Holter (24H) data after electrical cardioversion (CV) for atrial fibrillation (AF) recurrence. METHODS: We prospectively studied 47 consecutive patients subjected to CV, who successfully converted to sinus rhythm. All underwent echocardiography and 24H after CV. AF recurrence was studied at 14 days and 1 month by second 24H or by interim report of AF. RESULTS: About 53.2% remained in sinus rhythm (group I) and the rest recurred to AF (group II). Group I had fewer atrial premature complexes per hour (APC/h) (P = 0.002) and lower maximum (max HR), average, and minimum heart rates compared with group II (all Ps < 0.05). The optimal value of APC/h and max HR with best sensitivity and specificity was 32 APC/h and 90 bpm, respectively. These findings were the predictors of AF recurrence [hazard ratio (HR) = 4.5 with 95% CI = 1.7-11.7 and HR = 4.3 with 95% CI = 1.7-10.9, respectively]. Patients with the combination of both predictors had greater HR of AF recurrence compared with those with < 32 APC/h and max HR < 90 bpm (HR = 8.8 with 95% CI = 2.5-31.4). CONCLUSION: Patients with frequent APC/h and high max HR are at high risk for 1-month AF recurrence after electrical CV. 相似文献
24.
25.
Shelley A. Klemm Richard D. Gordon Terry J. Tunny Wendy L. Finn 《Clinical and experimental pharmacology & physiology》1990,17(3):191-195
1. Plasma potassium and chloride concentrations were raised and plasma renin activity, aldosterone, bicarbonate and arterial pH were reduced in two brothers with the syndrome of hypertension and hyperkalaemia with normal glomerular filtration rate (Gordon's syndrome), on unrestricted or moderately restricted sodium diets. 2. These abnormalities were corrected in both patients within 10 days of severe sodium restriction. 3. Pressor sensitivity to cold and angiotensin II decreased on low sodium diet, associated with a fall in blood pressure. 4. Increasing distal tubular sodium delivery by infusion of normal saline increased fractional excretion of potassium when aldosterone had been stimulated by severely restricted sodium diet, but not when aldosterone levels were low on unrestricted sodium diet. 5. These findings are consistent with excessive sodium reabsorption as the primary renal lesion in Gordon's syndrome, leading to volume expansion and suppression of renin and aldosterone. Severe dietary sodium restriction leading to volume contraction, by stimulating renin and aldosterone and promoting kaliuresis, corrects the abnormalities. 相似文献
26.
HEINER LANGENFELD AXEL KREIN MICHAEL KIRSTEIN LUDWIG BINNER† EUROPEAN PEA CLINICAL INVESTIGATION GROUP 《Pacing and clinical electrophysiology : PACE》1998,21(11):2187-2191
The peak endocardial acceleration (PEA, unit g) shows a near correlation with myocardial contractility during the isometric systolic contraction of the heart (dP/dtmax), with sympathetic activity and, thus, with physiological heart rate modulation. The (Biomechanical Endocardial Sorin Transducer (BEST) sensor is incorporated in the tip of a pacing lead and measures PEA directly near the myocardium. In an international study, the lead was implanted with the dual chamber pacemaker Living-1 (Sorin) in 105 patients. The behavior of the PEA signal was tested under conditions of physical and mental stress and during daily life activities by 24-hour recordings of PEA (PEA Holter) at 1 to 2 months and approximately 1 year after implantation. Implantation of the BEST lead was performed without complications in all patients. The sensor functioned properly in the short- and long-term in 98% of patients. Although PEA values differed from patient to patient, the values closely reflected the variations in sympathetic activity due to physical and mental stress in each patient. During exercise and during daily life activities a close correlation between PEA and heart rate was observed among patients with normal sinus rhythm. Peak endocardial acceleration allows a nearly physiological control of the pacing rate. 相似文献
27.
陈爱华 《南方医科大学学报》1990,(3)
本文用X线电影摄影方法评价了49例左室舒张(充盈)功能的影响因素。冠心病(CAD)组23例,高血压病组12例,正常对照组14例。左室充盈功能或顺应性主要受冠脉病变严重程度的影响。冠脉狭窄程度越重,并有陈旧性心肌梗塞、室壁运动异常、EF下降,则充盈功能受损愈明显。血压、年龄因素对舒张充盈功能的影响较小。在CAD组中,心率与1/3充盈分数呈负相关,与正常化高峰充盈率(NPFR)不相关,而EF则与NPFR相关良好。 相似文献
28.
G. Dewasmes B. Bothorel A. Hoeft V. Candas 《European journal of applied physiology》1993,66(6):542-546
Summary Thermoregulatory sweating [total body (m
sw,b), chest (m
sw,c) and thigh (m
sw,t) sweating], body temperatures [oesophageal (T
oes) and mean skin temperature (T
sk)] and heart rate were investigated in five sleep-deprived subjects (kept awake for 27 h) while exercising on a cycle (45 min at approximately 50% maximal oxygen consumption) in moderate heat (T
air andT
wall at 35° C. Them
sw,c andm
sw,t were measured under local thermal clamp (T
sk,1), set at 35.5° C. After sleep deprivation, neither the levels of body temperatures (T
oes,T
sk) nor the levels ofm
sw, b,m
sw, c orm
sw, t differed from control at rest or during exercise steady state. During the transient phase of exercise (whenT
sk andT
sk,1 were unvarying), them
sw, c andm
sw, t changes were positively correlated with those ofT
oes. The slopes of them
sw, c versusT
oes, orm
sw, t versusT
oes relationships remained unchanged between control and sleep-loss experiments. Thus the slopes of the local sweating versusT
oes, relationships (m
sw, c andm
sw, t sweating data pooled which reached 1.05 (SEM 0.14) mg·cm–2·min–1°C–1 and 1.14 (SEM 0.18) mg·cm–2·min–1·°C–1 before and after sleep deprivation) respectively did not differ. However, in our experiment, sleep deprivation significantly increased theT
oes threshold for the onset of bothm
sw, c andm
sw, t (+0.3° C,P<0.001). From our investigations it would seem that the delayed core temperature for sweating onset in sleep-deprived humans, while exercising moderately in the heat, is likely to have been due to alterations occurring at the central level. 相似文献
29.
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
30.
苯作业工人白细胞降低者的总估校正现患率 总被引:7,自引:0,他引:7
选择乡镇工业苯作业工人4次外周血白细胞计数中的间隔半年的两次数据,应用俘获再俘获法,计算其白细胞降低者的总估校正现患率(ACPR)。结果苯接触组为36.8l%(29.14%~44.48%),对照组为12.71%(7.20%~18.22%)具有显著差异,其相对危险度为2,9。用常规法求得的4次检出率分别是:苯接触组为26.37%,18.73%,27.93%,36.76%;对照组为6。85%,7.38%,7.94%,15.00%。均在其ACPR之95%可信限内,可见ACPR计算方法简便、结果准确,值得推广。对于稳定的人群,可用其每年一次的健康监护资料计算ACPR。 相似文献