全文获取类型
收费全文 | 9947篇 |
免费 | 570篇 |
国内免费 | 86篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 308篇 |
妇产科学 | 118篇 |
基础医学 | 1149篇 |
口腔科学 | 444篇 |
临床医学 | 883篇 |
内科学 | 2387篇 |
皮肤病学 | 230篇 |
神经病学 | 796篇 |
特种医学 | 473篇 |
外科学 | 1632篇 |
综合类 | 18篇 |
一般理论 | 1篇 |
预防医学 | 537篇 |
眼科学 | 93篇 |
药学 | 458篇 |
中国医学 | 11篇 |
肿瘤学 | 987篇 |
出版年
2024年 | 17篇 |
2023年 | 128篇 |
2022年 | 222篇 |
2021年 | 442篇 |
2020年 | 207篇 |
2019年 | 329篇 |
2018年 | 404篇 |
2017年 | 265篇 |
2016年 | 268篇 |
2015年 | 302篇 |
2014年 | 391篇 |
2013年 | 463篇 |
2012年 | 666篇 |
2011年 | 732篇 |
2010年 | 424篇 |
2009年 | 393篇 |
2008年 | 615篇 |
2007年 | 597篇 |
2006年 | 568篇 |
2005年 | 559篇 |
2004年 | 505篇 |
2003年 | 452篇 |
2002年 | 369篇 |
2001年 | 165篇 |
2000年 | 138篇 |
1999年 | 121篇 |
1998年 | 73篇 |
1997年 | 68篇 |
1996年 | 55篇 |
1995年 | 45篇 |
1994年 | 38篇 |
1993年 | 38篇 |
1992年 | 58篇 |
1991年 | 46篇 |
1990年 | 42篇 |
1989年 | 41篇 |
1988年 | 38篇 |
1987年 | 34篇 |
1986年 | 33篇 |
1985年 | 26篇 |
1984年 | 21篇 |
1983年 | 24篇 |
1982年 | 18篇 |
1980年 | 11篇 |
1979年 | 15篇 |
1977年 | 16篇 |
1975年 | 14篇 |
1974年 | 12篇 |
1973年 | 13篇 |
1968年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Capussotti L Ferrero A Sgotto E Viganò L Muratore A Polastri R 《Hepato-gastroenterology》2007,54(77):1557-1559
We report a case of a 37-year-old woman who was referred to a peripheral hospital with severe abdominal pain, vomiting and hemorrhagic shock. Ultrasonography and CT scan showed a large ruptured adenoma of the right liver. Because of hemodynamic instability, she underwent laparotomy with gauze packing and then she was referred to our department with a bleeding persisting at a rate of about 100 mL per hour from the abdominal drain. She underwent relaparotomy and a ruptured liver cell adenoma with a huge hepatic hematoma completely involving the right liver and part of segment 4 was confirmed. Considering the size of the lesion and the presence of a large hematoma, a right hepatectomy with anterior approach was performed. In case of emergency liver resections, the anterior approach is preferable not only to avoid tumor manipulation and the risk of its rupture, but mainly to reduce liver bleeding and to prevent sudden fall of the blood pressure due to inferior vena cava twisting in a hemodynamically instable patient. Intraoperative blood loss was 1500 mL. The postoperative course was uneventful. The patient is doing well ten months after operation. 相似文献
992.
Francesco Martino Pasquale Pignatelli Eliana Martino Francesco Morrone Roberto Carnevale Serena Di Santo Barbara Buchetti Lorenzo Loffredo Francesco Violi 《Journal of the American College of Cardiology》2007,49(19):1974-1981
OBJECTIVES: The aim of the study was to analyze the behavior of oxidative stress and its interplay with CD40L, a protein that is implicated in atherosclerosis, in hypercholesterolemic children. BACKGROUND: Oxidative stress has been suggested to play a major role in premature atherosclerosis. METHODS: Forty-one children with hypercholesterolemia (mean age 9.28 +/- 0.5 years) and 40 children with normocholesterolemia (mean age 9.02 +/- 0.69 years) were matched for gender and age. Within each group, children were classified as having or not having a family history of cardiovascular disease. Serum levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, and plasma levels of soluble CD40L (sCD40L) were measured in each child. In a subgroup of children with high (n = 8) or normal (n = 8) levels of serum cholesterol, platelet p38 mitogen-activated protein (MAP) kinase phosphorylation, a protein involved in the activation of nicotinamide adenine dinucleotide phosphate oxidase, was determined. RESULTS: Children with hypercholesterolemia had higher values of 8-OHdG and sCD40L compared with control subjects (0.55 +/- 0.06 ng/ml vs. 0.21 +/- 0.02 ng/ml, p < 0.001 and 0.55 +/- 0.04 ng/ml vs. 0.19 +/- 0.03 ng/ml, p < 0.001, respectively). A significant correlation between 8-OHdG and sCD40L was observed in children with high (r = 0.676, p < 0.001) or normal (r = 0.878, p < 0.001) levels of cholesterol. Children with a family history of cardiovascular disease tended to have higher values of 8-OHdG and sCD40L, but the difference was not significant. Analysis of platelet p38 MAP kinase showed that it was phosphorylated more in children with hypercholesterolemia compared with control subjects (36.8 +/- 5.8 AU vs. 8.0 +/- 4.5 AU, p < 0.001 respectively). CONCLUSIONS: Children with hypercholesterolemia have an early increase of oxidative stress that may be responsible for up-regulation of CD40L and potentially predispose to premature atherosclerosis. 相似文献
993.
Beretta L Caronni M Raimondi M Ponti A Viscuso T Origgi L Scorza R 《Clinical rheumatology》2007,26(2):168-172
Lung involvement constitutes nowadays the major cause of morbidity and mortality in scleroderma patients. Pulmonary fibrosis
in systemic sclerosis (SSc) is thought to be the consequence of interstitial inflammation. Early diagnosis and treatment of
active alveolitis is essential to prevent the deterioration of pulmonary function, improving outcome in SSc patients. The
aim of the study was to investigate the effect of 1-year treatment with oral cyclophosphamide (CYC) on the evolution of interstitial
lung disease in scleroderma patients with a diagnosis of active alveolitis. An open-label one-arm monocenteric study was conducted
on 33 scleroderma patients with active alveolitis—defined as the presence of areas of ‘ground-glass attenuation’ on high-resolution
computed tomography and a recent deterioration in lung function—treated with oral CYC 2 mg kg−1 day−1 for 1 year and medium-low dose steroids (prednisone 25 mg for 3 months and then tapered to 5 mg/day). Results showed that
diffusing capacity for carbon monoxide (DLco) values remained stable after 6 months of treatment and significantly increased
after 12 months (2.06±1.38, 2.21±1.62 and 2.39±1.64 mmol/min/kPa, at baseline/6/12 months, respectively; p<0.001 12th month vs baseline) vital capacity (VC) values slightly increased (i.e. stabilised) in the same time frame (2.46±0.71,
2.41±0.76 and 2.56±0.75 l). Accordingly, the vast majority of our patients (n=29, 87.9%) presented a DLco and/or a VC improvement or stabilisation with respect to baseline. Favourable results were more
likely to be observed in patients with a lower Wells’ radiological grade (grade I). In 25 patients followed up for further
12 months after the interruption of therapy, VC and DLco remained stable. Thus, long-term therapy with oral CYC is effective
in ameliorating and/or stabilising lung function in scleroderma patients with active alveolitis, with beneficial effects lasting
up to 1 year after interruption. The higher efficacy in those patients with an early pulmonary disease stage and a lower radiological
grade underlies the importance of an early diagnosis and intervention. 相似文献
994.
Viazzi F Leoncini G Ratto E Falqui V Parodi A Conti N Derchi LE Tomolillo C Deferrari G Pontremoli R 《American journal of hypertension》2007,20(12):1276-1282
BACKGROUND: Subclinical renal damage and hyperuricemia are not uncommon in patients with primary hypertension. Whether mild hyperuricemia reflects a subclinical impairment of renal function or contributes to its development is currently debated. We investigated the relationship between serum uric-acid levels and the occurrence of early signs of kidney damage. METHODS: Four hundred eighteen patients with primary hypertension were studied. Albuminuria was measured as the albumin-to-creatinine ratio, and creatinine clearance was estimated by the formula of Cockcroft and Gault. Interlobar resistive index and renal abnormalities, ie, the renal volume-to-resistive index ratio, were evaluated by renal Doppler and ultrasound. RESULTS: Uric acid was directly related to resistive index (P = .007) in women and to albuminuria (P = .04) in men, and was inversely related to the renal volume-to-resistive index ratio in both men (P = .005) and women (P = .02). Patients with uric-acid levels above the median showed a higher prevalence of microalbuminuria (14% v 7%, P = .012) and of renal abnormalities (41% v 33%, P = .007). Moreover, when creatinine clearance was taken as a covariate, patients with increased uric-acid levels showed higher albuminuria and resistive indices, and a lower renal volume-to-resistive index ratio. Even after adjustment for several risk factors, each standard deviation increase in serum uric acid entailed a 69% higher risk of microalbuminuria, and a 39% greater risk of ultrasound detectable renal abnormalities. CONCLUSIONS: Mild hyperuricemia is associated with early signs of renal damage, ie, microalbuminuria and ultrasound-detectable abnormalities, regardless of the glomerular filtration rate in primary hypertension. 相似文献
995.
Ghiadoni L Versari D Magagna A Kardasz I Plantinga Y Giannarelli C Taddei S Salvetti A 《Journal of hypertension》2007,25(2):361-366
DESIGN AND PARTICIPANTS: A double-blind, crossover, randomized study was designed to evaluate the effect of 3-month treatment with a lower versus a higher antihypertensive dosage of ramipril (5 or 10 mg/day) on nitric oxide (NO)-dependent vasodilation in 46 untreated patients with essential hypertension. Radial artery flow-mediated dilation (FMD), before and after the intra-arterial infusion of NG-monomethyl-L-arginine (L-NMMA), to block NO synthase, and the response to sublingual glyceril trinitrate (GTN, 25 microg) were measured at baseline and after the two treatment periods as a change in artery diameter (computerized system from ultrasound scans). Plasma angiotensin II and oxidative stress markers were also assessed. RESULTS: FMD was significantly (P < 0.01) lower in hypertensive patients (4.6 +/- 1.8%) than in normotensive subjects (7.1 +/- 2.6%), whereas the response to GTN was similar. L-NMMA significantly (P < 0.001) inhibited FMD in normotensive but not in hypertensive subjects. Mean 24-h ambulatory blood pressure, plasma angiotensin II and oxidative stress marker levels were similarly reduced at the end of the two treatment periods. Both dosages of ramipril significantly (P < 0.001) increased FMD (5 mg: 5.9 +/- 2.1%; 10 mg: 6.3 +/- 2.4%) without modifying the response to GTN. However, compared with baseline (11 +/- 19%), the inhibiting effect of L-NMMA on FMD (NO-dependent FMD) was significantly (P < 0.01) greater with ramipril 10 mg (49 +/- 12%) than 5 mg per day (38 +/- 15%). The improvement in FMD and NO-dependent FMD was not related to changes in plasma levels of angiotensin II or markers of oxidative stress. CONCLUSION: Treatment with ramipril at a higher dosage induced a greater improvement in NO-dependent vasodilation compared with the lower antihypertensive dosage in hypertensive patients. 相似文献
996.
Sanchís J Bodí V Llácer A Facila L Martínez-Brotons A Insa L Chorro FJ 《Revista espa?ola de cardiología》2004,57(5):382-387
INTRODUCTION AND OBJECTIVES: The mechanism responsible for elevated C-reactive protein levels (inflammation of the ruptured atherosclerotic plaque or myocardial necrosis) in acute coronary syndromes is controversial. The aim of this study was to investigate the relationship between C-reactive protein levels and angiographic complexity of the culprit lesion and troponin elevation in patients with non-ST elevation acute coronary syndromes. PATIENTS AND METHOD: The study group consisted of 125 patients with single-vessel disease. Troponin-I and C-reactive protein were measured, and the complexity of the culprit lesion was analyzed (TIMI flow and thrombus). Information on age, sex, smoking habit, hypertension, hypercholesterolemia and diabetes was obtained from the medical record. RESULTS: The quartile distribution of C-reactive protein showed more patients with TIMI flow < 3 (31%, 28%, 18%, and 55%; P=.02), thrombus (3%, 6%, 7%, and 28%; P=.007) and troponin-I elevation (19%, 44%, 50%, and 66%; P=.003) in the fourth quartile. Multivariate analysis showed both thrombus (OR = 4.1; 95% CI, 1.2-14.3; P=.03) and troponin elevation (OR = 2.6; 95% CI, 1.1-6.3; P=.03) to be associated with C-reactive protein > 18 mg/L (fourth quartile cut-off). When treated as a continuous variable, higher levels of C-reactive protein were also associated with thrombus (P=.02) and troponin elevation (P=.003). No other clinical variables were related with C-reactive protein levels. CONCLUSIONS: Both angiographic complexity of the culprit lesion and elevated troponin level are related with increased C-reactive protein levels in non-ST elevation acute coronary syndromes. 相似文献
997.
López Montes A Lorenzo I Pérez Martínez J 《Nefrología : publicación oficial de la Sociedad Espa?ola Nefrologia》2004,24(Z3):85-88
We report the case of a 37-years-old woman with inappropriate antidiuretic hormone syndrome due to an attack of acute porphyria. The patient was admitted to our hospital for abdominal pain, sleepiness and pink urine. Family and personal history were normal. Seven days before the admission the patient had a laparoscopy operation for endometriosis in her left ovary. The patient had had two normal pregnancies. The physical examination was normal, the skin turgor was good and no edema was present, the blood pressure was 140/90 mmHg. Her serum sodium was 114 mEq/L, serum osmolality 243 mOsm/kg, urine sodium 146 mEq/L and urine osmolality 457 mOsm/kg. Values from laboratory examination revealed a normal peripheral haematogram, a normal kidney function, normal liver, adrenal and thyroid function. The urine tested for amino-levulinic acid, coproporphyrin and uroporphyrin was strongly positive. These findings are compatible with Porphyria Variegata or Coproporphyria Hereditary. A diagnosis of Porphyria acute with SIADH was made, and water fluid restriction, i.v. hypertonic saline infusion and furosemide to correct the hyponatremia was begun. In 1966, lesions of the median eminence of the hypothalamus and both hypothalamic -hypophyseal tracts were described in a patient with Porphyria acute intermittent and SIADH. It was suggested that SIADH occurred because of damage to these areas of the brain from excessive exposure to porphyrins. 相似文献
998.
De Ferrari GM Klersy C Ferrero P Fantoni C Salerno-Uriarte D Manca L Devecchi P Molon G Revera M Curnis A Sarzi Braga S Accardi F Salerno-Uriarte JA;ALPHA Study Group 《European journal of heart failure》2007,9(5):502-509
BACKGROUND: Estimates of the prevalence of atrial fibrillation (AF) in heart failure (HF) originate from patients enrolled in clinical trials. AIMS: To assess the prevalence and clinical correlates of AF among HF patients in everyday clinical practice from HF patients screened for the T-wave ALternans in Patients with Heart fAilure (ALPHA) study; to investigate the correlation between AF and functional status. METHODS AND RESULTS: Consecutive patients (N=3513) seen at nine Heart Failure Clinics were studied; 21.4% were in AF. AF prevalence was greater with increasing age (OR 1.04/year, p<0.001) in non-ischaemic cardiomyopathy (OR 2.34, p<0.001) and with increasing NYHA class (p<0.0001). Multiple logistic regression predictors of AF were age >70 years (OR 2.35), NYHA class II III or IV vs class I (OR 1.8, 4.4 and 3.1) and non-ischaemic cardiomyopathy (OR 3.2). A logistic model indicated that AF was associated with a 2.5 OR of being in NYHA class III-IV vs I-II while accounting for age, gender, left ventricular ejection fraction (LVEF), and aetiology of HF. CONCLUSIONS: The prevalence of AF in HF patients exceeds 20%, and increases with age and functional class. The presence of AF leads to a more severe NYHA class, indicating that AF contributes to the severity of heart failure. 相似文献
999.
Usefulness of C-reactive protein and left ventricular function for risk assessment in survivors of acute myocardial infarction 总被引:2,自引:0,他引:2
Sanchis J Bodí V Llácer A Núñez J Facila L Ruiz V Blasco M Sanjuán R Chorro FJ 《The American journal of cardiology》2004,94(6):766-769
The additional prognostic information provided by C-reactive protein (CRP) to parameters of left ventricular function in survivors of acute myocardial infarction (AMI) was investigated in 665 patients (326 with ST elevation and 339 with non-ST elevation). Cox multivariable analysis identified the following predictors of 6-month cardiac death: age (per 5 years hazard ratio [HR] 1.2, 95% confidence interval [CI] 1.1 to 1.4, p = 0.004), Killip class >I at presentation (HR 2.4, 95% CI 1.3 to 4.5, p = 0.0001), a reduced ejection fraction (per 5% HR 1.3, 95% CI 1.2 to 1.4, p = 0.0001), and greater CRP (per 5 mg/L HR 1.02, 95% CI 1.01 to 1.04, p = 0.02); the C-index of the model was 0.77 without and 0.78 with CRP. CRP is associated with mortality in addition to age and parameters of ventricular function (Killip class and ejection fraction) in survivors of AMI, although the relevance of its additive predictive role seems marginal. 相似文献
1000.
Immunoglobulin gene analysis reveals 2 distinct cells of origin for EBV-positive and EBV-negative Burkitt lymphomas 下载免费PDF全文
Bellan C Lazzi S Hummel M Palummo N de Santi M Amato T Nyagol J Sabattini E Lazure T Pileri SA Raphael M Stein H Tosi P Leoncini L 《Blood》2005,106(3):1031-1036
The normal counterpart of the neoplastic B cells in Burkitt lymphoma (BL) is still unclear. Based on immunoglobulin gene rearrangement studies, some authors suggest an origin from germinal center cells and others from memory B cells. However, most of these studies rely on cell lines or on a small series of cases. To help clarify the cell of origin of BL, semi-nested polymerase chain reaction (PCR) was performed to amplify the VDJ rearrangements of the immunoglobulin heavy chain (V(H)) genes, and the resultant amplificates were sequenced for comparison with known germline V(H) segments. The results of this approach revealed that all cases (15 endemic BL [eBL], 10 sporadic BL [sBL], and 6 AIDS-related BL) harbor mutated V(H) genes, with different mutation ranges among the 3 types of BL. The eBL and AIDS-related forms showed considerably higher mutation rates than the sBL form (5.1%, 5.4%, and 1.5%, respectively). The mutations in eBL and AIDS-related BL also showed signs of antigen selection, whereas no signs of antigen selection were found in sBL. Finally, after subcloning the amplificates, sequence analysis revealed no signs of ongoing mutations in any of the cases analyzed. Given that one of the main differences between eBL and AIDS-related BL on the one hand and sBL on the other hand is the association with Epstein-Barr virus (EBV), we compared EBV-positive and EBV-negative BLs independently of their geographic origin and HIV status. The differences in the number of somatic mutations and antigen selection were even more evident when this approach was used. According to our molecular results, it appears that EBV-positive and EBV-negative BL may originate from 2 distinct subsets of B cells, pointing to a particular role for the germinal-center reaction in the pathogenesis of these tumors. The different types of C-MYC translocation reported in BL may also be related to the different stages of B-cell maturation. 相似文献