全文获取类型
收费全文 | 125105篇 |
免费 | 8444篇 |
国内免费 | 2802篇 |
专业分类
耳鼻咽喉 | 366篇 |
儿科学 | 3279篇 |
妇产科学 | 942篇 |
基础医学 | 5849篇 |
口腔科学 | 597篇 |
临床医学 | 19696篇 |
内科学 | 39449篇 |
皮肤病学 | 420篇 |
神经病学 | 3308篇 |
特种医学 | 3124篇 |
外国民族医学 | 1篇 |
外科学 | 13107篇 |
综合类 | 21192篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 5383篇 |
眼科学 | 325篇 |
药学 | 11500篇 |
108篇 | |
中国医学 | 5564篇 |
肿瘤学 | 2136篇 |
出版年
2024年 | 1230篇 |
2023年 | 1987篇 |
2022年 | 3689篇 |
2021年 | 5228篇 |
2020年 | 4970篇 |
2019年 | 4452篇 |
2018年 | 4227篇 |
2017年 | 3849篇 |
2016年 | 4029篇 |
2015年 | 4228篇 |
2014年 | 9421篇 |
2013年 | 9033篇 |
2012年 | 7369篇 |
2011年 | 8157篇 |
2010年 | 6515篇 |
2009年 | 6102篇 |
2008年 | 6030篇 |
2007年 | 6130篇 |
2006年 | 5429篇 |
2005年 | 4861篇 |
2004年 | 3780篇 |
2003年 | 3261篇 |
2002年 | 2599篇 |
2001年 | 2544篇 |
2000年 | 2000篇 |
1999年 | 1838篇 |
1998年 | 1533篇 |
1997年 | 1448篇 |
1996年 | 1272篇 |
1995年 | 1112篇 |
1994年 | 1077篇 |
1993年 | 816篇 |
1992年 | 746篇 |
1991年 | 728篇 |
1990年 | 634篇 |
1989年 | 526篇 |
1988年 | 502篇 |
1987年 | 405篇 |
1986年 | 369篇 |
1985年 | 389篇 |
1984年 | 375篇 |
1983年 | 228篇 |
1982年 | 257篇 |
1981年 | 205篇 |
1980年 | 184篇 |
1979年 | 154篇 |
1978年 | 119篇 |
1977年 | 81篇 |
1976年 | 73篇 |
1975年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
D Mahalanabis H Ashraf MM Rahman GJ Fuchs 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(11):1113-1115
One-hundred and six male children aged 6-23 months with a history of acute watery diarrhoea of less than 72 h duration were randomized to receive either folic acid in a dose of 5 mg at 8-h intervals or placebo for 5 d. There were 54 children in the folic acid group and 52 in the placebo group. The admission characteristics were comparable between the two groups. No significant differences were observed in the intake of oral rehydration solution or stool output between the groups. The mean ± SD of total stool output (g kg−1 ) was 532 ± 476 vs 479 ± 354 and the duration (h) of diarrhoea was 108 ± 68 vs 103 ± 53 in the folic acid vs placebo group, respectively. The findings, therefore, should have a positive influence on preventing the inappropriate use of folic acid in acute diarrhoea. 相似文献
72.
Ignatius KP CHENG 《Nephrology (Carlton, Vic.)》1997,3(1):109-111
Summary: The involvement of the IgA immune system and complement components in IgA glomerulonephritis (IgAGN) has prompted the use of immunosuppressive drugs in therapy, but none has so far been shown to alter the natural course of the disease. Because most patients with IgAGN present during the chronic phase of their illness, at the time when the initiating immune events may no longer be active, nonimmune therapy which targets the common pathway of progressive renal injury is likely to be more useful. There is increasing evidence that angiotensin-converting enzyme inhibitors (ACEI) reduce proteinuria and renal injury in patients with IgAGN, and this effect may be observed in both normotensive and hypertensive patients. Yet to be determined is whether this effect is specific for ACEI and whatever other effective antihypertensive drugs may achieve a similar result. Fish oil has recently been shown to retard the progression of renal failure in patients with aggressive IgAGN, but a narrow therapeutic window appears to exist for this form of treatment. Antiplatelet agents on their own appear to be ineffective but in combination with anticoagulation (low dose warfarin) have been shown to have an antiproteinuric effect and may preserve renal function in patients with progressive disease. Future directions of non-immune therapy of IgAGN include evaluation of the renoprotective effect of angiotensin II receptor antagonists, free-radical scavengers and antilipid drugs. More work should also be done to identify factors which put the patients at risk of developing progressive disease and which predict therapeutic response, as has been done recently with the identification of the deletion polymorphism of the angiotensin-converting enzyme gene as a marker of progressive disease and therapeutic response to ACEI in patients with IgAGN. 相似文献
73.
Splanchnic ischaemia and its role in multiple organ failure 总被引:3,自引:0,他引:3
Multiple organ failure remains the leading cause of death in the intensive care unit. Increasing numbers of investigators have focused their attention on the role of gastrointestinal tract in the pathogenesis of this syndrome. Their data indicate that inadequate gut perfusion leads to a measurable imbalance between oxygen delivery and the needs of the tissues, i.e., ischaemia. Gut ischaemia of sufficient duration impairs gastrointestinal tract barrier function, facilitating the passage of enteric bacterial endotoxin into the circulation. It has been hypothesized that production of tumor necrosis factor α, and other biologic mediators by endotoxin–stimulated macrophages, triggers a generalized and uncontrolled inflammatory response that ultimately leads to multiple organ failure.
Preliminary evidence suggests that survival can be improved significantly if gut ischaemia is promptly identifed and aggressively treated by administration of fluids and inotropic drugs, using gastric intramucosal pH as the therapeutic endpoint. Future studies are needed to determine whether additional treatment modalities can improve outcome once the inflammatory response has fully developed. 相似文献
Preliminary evidence suggests that survival can be improved significantly if gut ischaemia is promptly identifed and aggressively treated by administration of fluids and inotropic drugs, using gastric intramucosal pH as the therapeutic endpoint. Future studies are needed to determine whether additional treatment modalities can improve outcome once the inflammatory response has fully developed. 相似文献
74.
BERND-DIETER GONSKA KEJIANG CAO ANSELM SCHAUMANN AXEL DORSZEWSKI FRIEDERIKE von zur MÜHLEN HEINRICH KREUZER 《Pacing and clinical electrophysiology : PACE》1994,17(3):542-549
The management of patients after catheter ablation of ventricular tachycardia is not well defined. In this article we summarize recently published results and report our own experience. Factors influencing the clinical outcome of these patients and methods to identify patients with an increased risk of recurrence of ventricular tachycardia are discussed. Furthermore, a review is given on current concomitant therapeutic tools including antiarrhythmic drugs and the implantation of an automatic cardioverter defibrillator. 相似文献
75.
Acute toxicity of two pyrethroids,permethrin, and cypermethrin in neonatal and adult rats 总被引:2,自引:0,他引:2
Franco Cantalamessa 《Archives of toxicology》1993,67(7):510-513
The present study aims specifically at obtaining a comparison of the acute toxicity of cypermethrin (CY), a type I pyrethroid, and permethrin (PERM), a type II pyrethroid, administered orally as a single dose to neonatal and adult rats, and at assessing the importance of pyrethroid biotransformation in CY and PERM toxicity through use of drug metabolism inhibitors. Our experiments show that CY is more toxic than PERM to adult and neonatal rats. The sensitivity of neonatal rats both to CY and to PERM toxicity is higher, the younger the animals. CY is much more toxic than PERM in the neonatal rat, compared with the adult. In rats aged 8, 16, and 21 days, pretreatment with piperonil butoxide (PB), a monooxygenase inhibitor, or with tri-o-tolyl phosphate (TOTP), an esterase inhibitor, does not produce significant variations in the lethal effects of CY and PERM. Instead, in the adult rats, a significant increase in CY (X2=5.97;p<0.05) and PERM (X2=4.37;p<0.05) mortality occurred in rats pretreated with esterase inhibitors, whereas no increase in CY and PERM toxicity was found in adult animals pretreated with monooxygenase inhibitor. It was concluded that the higher level of sensitivity of the neonate rat to pyrethroid toxicity is probably due to incomplete development of the enzymes which catalyze the metabolism of pyrethroids in the liver of young animals. It is suggested that ester hydrolysis is an important pyrethroids detoxification reaction in the adult rat. 相似文献
76.
分析了1984~1993年期间47例经治的急性视神经炎患者。治疗应用地塞米松10mg、青霉素480万u静脉点滴7天,随后减量。结果治愈35例(74.47%),好转6例(12.76%),无效2例(4.26%),转院及自动出院各2例。47例中11例治疗效果不好者行筛窦开放术后,视力逐渐恢复正常,显示筛窦开放术有其临床实用价值。 相似文献
77.
L. Bjertnaes J. Vaage S. M. Almdahl M. Lil P. A. Nilsen K. Hansen J. Solbø Å. Jolin R. Hotvedt K. Olafsen A. Bröndbo J. Thoner M. Gilbert O. Hevrøy G. Bjørsvik N. Hesselberg H. Bergland O. Sivertsen 《Acta anaesthesiologica Scandinavica》1996,40(3):293-301
Extracorporeal membrane oxygenation (ECMO) may serve as extracorporeal lung assist (ECLA) in patients with acute respiratory failure (ARF) or as extracorporeal heart assist (ECHA) in patients with low output syndrome (LOS) after open heart surgery. From 1988 to 1992 seven patients underwent ECMO in our hospital; four suffered from ARF and three from LOS. Various bypass techniques were employed. Two ARF patients, aged 58 and 18 years, had veno-venous bypass; in the latter, ECMO was reinstituted as a veno-arterial bypass one week after weaning. In a three-year-old boy, the ECMO outflow tubing was primarily connected to the pulmonary artery, and shortly afterwards relocated to the common carotid artery. In a 31-year-old man with ARF, and three LOS patients, a 56-year-old woman, and two men aged 68 and 70 years, ECMO was veno-arterial with direct access to the ascending aorta. A heparin-coated system was used, and all but one patient, who was treated with warfarin, received a daily low dose of heparin, which was withdrawn after from one to nine days.
Six patients were weaned off ECMO after 4.5 to 21 days. Three ARF patients recovered completely; the child died. In one LOS patient, ECMO was withdrawn due to a poor general condition. Two others were weaned off ECMO and the intra-aortic balloon pump, and the inotropic support was significantly reduced, but both died of multiple system organ failure. Although no firm conclusions can be drawn from these few case reports, the heparin-coated system used as ECLA appears promising, whereas ECHA seems to imply a poor prognosis in patients who are not candidates for cardiac transplantation. 相似文献
Six patients were weaned off ECMO after 4.5 to 21 days. Three ARF patients recovered completely; the child died. In one LOS patient, ECMO was withdrawn due to a poor general condition. Two others were weaned off ECMO and the intra-aortic balloon pump, and the inotropic support was significantly reduced, but both died of multiple system organ failure. Although no firm conclusions can be drawn from these few case reports, the heparin-coated system used as ECLA appears promising, whereas ECHA seems to imply a poor prognosis in patients who are not candidates for cardiac transplantation. 相似文献
78.
Michael H Duong Todd A MacKenzie David J Malenka 《Catheterization and cardiovascular interventions》2005,64(4):471-479
The objectives of this study was to assess the overall effect of N-acetylcysteine (NAC) in preventing radiocontrast-induced nephropathy (RCIN) using all available data in the literature. RCIN is associated with increased morbidity and mortality. Existing randomized trials of NAC are small and show inconsistent results. Prior meta-analyses do not include data from the most current studies. We used standard search protocols to identify all published articles and abstracts of prospective trials using NAC with fluid hydration compared to hydration alone in patients with chronic renal insufficiency undergoing contrast procedures. A rise in serum creatinine by 0.5 mg/dl or 25% above baseline at 48-72 hr after contrast exposure was used as the primary outcome. We identified 14 trials of NAC with 1,584 patients published as full-text articles. Using a random-effects model, the use of oral NAC resulted in a significant reduction in the risk for developing RCIN (RR = 0.57; 95% CI = 0.37-0.84; P = 0.01). This finding did not significantly change in a fixed-effect model (RR = 0.55; 95% CI = 0.42-0.73) or when the data were reanalyzed using only randomized trials in all forms (i.e., articles and abstracts; RR = 0.67; 95% CI = 0.47-0.95). We identified only one important difference between the positive and the negative studies: the cumulative exposure to contrast media (174 vs. 152 ml). Metaregression did not show a significant relationship between contrast volume and the RR of developing RCIN (P > 0.10). In the trials showing benefit for NAC, the treated patients' postprocedure creatinine unexpectedly decreased by 0.21 mg/dl (95% CI = 0.33-0.08). Prophylaxis with NAC significantly reduces the risk for RCIN. The reasons for improvement in serum creatinine in patients treated with NAC are unclear, but may include improved renal blood flow due to NAC and/or vigorous hydration. 相似文献
79.
P M Srivastava P Calafiore R J MacIsaac D L Hare G Jerums L M Burrell 《Diabetic medicine》2004,21(8):945-950
BACKGROUND: Patients with diabetes mellitus have a high incidence of coronary heart disease and congestive heart failure (CHF). Thiazolidinediones (TZD) are a new class of pharmacological agents for the treatment of Type 2 diabetes mellitus, which have many beneficial cardiovascular effects. Peripheral oedema and weight gain have been reported in 4.8% of subjects on TZDs alone, with a higher incidence noted in those receiving combination insulin therapy (up to 15%), but there is limited data on the occurrence of CHF. METHODS AND RESULTS: In this paper, we report on six cases of TZD-induced fluid retention with symptoms and signs of peripheral oedema and/or CHF that occurred in subjects attending our diabetic clinic. The predominant finding in all cases was of diastolic dysfunction. All subjects were obese and hypertensive, with 5/6 having the additional risk factor of LVH, 5/6 subjects had microvascular complications, whilst 3/6 were also on insulin therapy. CONCLUSION: We suggest that obese, hypertensive diabetics may benefit from echocardiographic screening prior to commencement of TZDs, as these agents may exacerbate underlying undiagnosed left ventricular diastolic dysfunction. 相似文献
80.
Jihad R Salameh Morris E Franklin 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2004,8(1):61-64
BACKGROUND AND OBJECTIVES: Laparoscopy in patients with poor cardiac function has been the subject of controversy and is considered by many surgeons a relative contraindication. METHODS: We report the case of a patient who presented with acute cholecystitis and choledocholithiasis concurrent with unstable angina. Our experience in laparoscopic management of patients with calculous biliary disease and severe coronary artery disease is examined. RESULTS: The patient was managed by coronary angioplasty and stenting immediately followed by laparoscopic cholecystectomy and common bile duct exploration under close invasive hemodynamic monitoring and low-pressure pneumoperitoneum. Between 1996 and 2001, 39 patients with coronary artery disease and an ASA class of III or IV underwent laparoscopic cholecystectomy. Eight of these patients (20.5%) had common bile duct stones necessitating laparoscopic common bile duct exploration. No conversions were necessary, and no major morbidity or mortalities occurred. CONCLUSIONS: Laparoscopic cholecystectomy and common bile duct exploration can be safely performed in patients with severe ischemic cardiac disease under close hemodynamic monitoring and a low-pressure pneumoperitoneum (10 to 12 mm Hg). 相似文献