全文获取类型
收费全文 | 37792篇 |
免费 | 2063篇 |
国内免费 | 247篇 |
专业分类
耳鼻咽喉 | 285篇 |
儿科学 | 895篇 |
妇产科学 | 830篇 |
基础医学 | 4441篇 |
口腔科学 | 809篇 |
临床医学 | 2840篇 |
内科学 | 9170篇 |
皮肤病学 | 733篇 |
神经病学 | 3929篇 |
特种医学 | 1175篇 |
外国民族医学 | 1篇 |
外科学 | 5636篇 |
综合类 | 202篇 |
一般理论 | 12篇 |
预防医学 | 2115篇 |
眼科学 | 704篇 |
药学 | 2251篇 |
中国医学 | 89篇 |
肿瘤学 | 3985篇 |
出版年
2023年 | 216篇 |
2022年 | 515篇 |
2021年 | 1021篇 |
2020年 | 617篇 |
2019年 | 818篇 |
2018年 | 989篇 |
2017年 | 758篇 |
2016年 | 834篇 |
2015年 | 982篇 |
2014年 | 1372篇 |
2013年 | 1780篇 |
2012年 | 2626篇 |
2011年 | 2614篇 |
2010年 | 1605篇 |
2009年 | 1449篇 |
2008年 | 2320篇 |
2007年 | 2403篇 |
2006年 | 2239篇 |
2005年 | 2153篇 |
2004年 | 2164篇 |
2003年 | 1868篇 |
2002年 | 1861篇 |
2001年 | 681篇 |
2000年 | 554篇 |
1999年 | 547篇 |
1998年 | 411篇 |
1997年 | 337篇 |
1996年 | 319篇 |
1995年 | 294篇 |
1994年 | 222篇 |
1993年 | 219篇 |
1992年 | 347篇 |
1991年 | 301篇 |
1990年 | 292篇 |
1989年 | 273篇 |
1988年 | 227篇 |
1987年 | 190篇 |
1986年 | 197篇 |
1985年 | 178篇 |
1984年 | 174篇 |
1983年 | 120篇 |
1982年 | 92篇 |
1981年 | 87篇 |
1980年 | 55篇 |
1979年 | 73篇 |
1977年 | 59篇 |
1976年 | 48篇 |
1975年 | 47篇 |
1974年 | 52篇 |
1973年 | 49篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Massimo Lemma Andrea Mangini Guido Gelpi Andrea Innorta Paolo Danna Francesco Lavarra Emanuela Piccaluga Carlo Antona 《European journal of cardio-thoracic surgery》2003,24(1):81-5; discussion 85
OBJECTIVE: It is not well established whether the blood flow of arterial composite Y-grafts can efficiently respond to the flow demand of the coronary system early postoperatively. The aim of this study was to evaluate if soon after the operation, arterial composite Y-grafts can increase blood flow in response to an increase in myocardial oxygen consumption (MVO2). METHODS: Twenty-seven patients who received complete arterial myocardial revascularization using the left internal thoracic artery (LITA) and the radial artery (RA) as composite Y-graft gave their consent to a pre-discharge coronary angiography and intravascular flow velocity measurements using a Doppler guide wire. Flow measurements were performed in the LITA main stem, the distal LITA and the RA, both at rest and during atrial pacing at the 85% of the patient age-predicted maximum. The heart rate-systolic blood pressure product was considered as an indirect index of MVO2. Hyperemic flow was determined after injection of adenosine. The flow reserve (FR) was defined as the ratio of blood flow during maximal hyperemia (Qmax) to baseline flow (Qbasal). RESULTS: Atrial pacing increased MVO2 significantly (P<0.000). None of the patients developed ischemic S-T segment modifications or complained of chest pain. Q(basal) increased significantly in the LITA main stem (P=0.001), distal LITA (P=0.041) and RA (P=0.004) while Qmax did not change significantly. As a consequence, the FR decreased in the LITA main stem (P=0.002), distal LITA (P<0.000) and RA (P<0.000) but was not completely exhausted. CONCLUSIONS: Soon after the operation, arterial composite Y-grafts can significantly increase blood flow in response to conditions of increased MVO2, keeping normal the myocardial O2 supply-to-demand ratio. 相似文献
52.
53.
Retroperitoneal leiomyosarcoma mimicking acute appendicitis: laparoscopic management. 总被引:2,自引:0,他引:2
Ferdinando Agresta Paolo De Simone Ivan Michelet Natalino Bedin 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2003,7(2):177-179
BACKGROUND: Retroperitoneal leiomyosarcomas (RLMS) are a challenging clinical entity. The vast majority of patients are operated on when tumors are advanced. We report herein a case of RLMS, mimicking acute appendiceal disease and treated successfully via laparoscopy. METHODS: A 37-year-old woman, para 1, was admitted to our department for right lower quadrant abdominal pain, fever, and leukocytosis. She had no changes in gastrointestinal and urologic function. A physical examination revealed the presence of abdominal guarding, rebound, and a tender mass in the right lower quadrant. The abdominal ultrasound showed an inhomogeneous ovoid mass (6 cm in diameter) located below the cecum, with no definite margins, and consistent with an appendiceal abscess. The patient was referred for laparoscopy. The procedure was performed with the aid of 3 ports: a 12-mm trocar in the umbilicus (open technique), a 10-mm trocar in the left iliac fossa, and a 5-mm one in the supra-pubic space. On inspection of the abdominal cavity, a retroperitoneal 6-cm mass was immediately found below the cecum and the appendix. Neither intraperitoneal seeding nor suspected lymph nodes were present. After dissection of the parietal peritoneum, the mass appeared to be encapsulated and well demarcated from all surrounding structures. It was eventually dissected and removed via a plastic bag. A standard appendectomy was also performed. The postoperative course was uneventful, and the patient was discharged on the 3rd day. The histology analysis of the resected specimen showed a totally excised G2 leiomyosarcoma. The appendix had no signs of inflammation. Postoperatively, the patient underwent a total-body CT-scan, which had no signs of residual or distant disease. No adjuvant therapy was necessary. At an 18-month follow-up, the patient was doing well and was disease free. CONCLUSION: Surgery represents the main therapeutic option for resectable RLMS. Laparoscopy is a useful diagnostic tool that allows safe resection of incidentally discovered, small and well encapsulated RLMS. 相似文献
54.
Vincenzo La Milia Salvatore Di Filippo Monica Crepaldi Simeone Andrulli Lucia Del Vecchio Pietro Scaravilli Giovambattista Virga Francesco Locatelli 《Nephrology, dialysis, transplantation》2004,19(7):1849-1855
BACKGROUND: Sodium removal (NaR) may have a major impact on the survival of peritoneal dialysis patients. The dialysate/plasma sodium concentration ratio (D/P(Na)) is an indirect index of transcellular water transport by aquaporin channels, and thus of ultrafiltration. Sodium concentration can be assessed by means of flame photometry (F), and direct (D-ISE) or indirect ion-selective electrodes (I-ISE), but these methods have different properties. I-ISE is being used increasingly in clinical laboratories. The aim of this study was to evaluate NaR and D/P(Na) using the three different measurement methods. METHODS: We performed peritoneal equilibration tests (PETs) in 44 peritoneal dialysis patients and calculated the NaR. We also calculated D/P(Na) during the test; plasma and dialysate sodium concentrations were measured by F, D-ISE and I-ISE. RESULTS: NaR was lower (P<0.001) with D-ISE (69+/-29 mmol) than with F (81+/-29 mmol) or I-ISE (79+/-28 mmol). D/P(Na) was also lower at baseline (0.92+/-0.02 vs 0.95+/-0.02 and 0.95+/-0.02; P<0.001), after 60 min (0.87+/-0.03 vs 0.90+/-0.03 and 0.90+/-0.03; P<0.001) and at the end of PET (0.88+/-0.04 vs 0.92+/-0.04 and 0.92+/-0.04; P<0.001) when measured by D-ISE in comparison with F and I-ISE, respectively. CONCLUSIONS: NaR and D/P(Na) were lower when measured by the D-ISE method compared with the F and I-ISE methods. NaR and D/P(Na) were similar when measured by F or I-ISE. I-ISE can be used reliably in the evaluation of NaR and D/P(Na) in everyday clinical practice of peritoneal dialysis. 相似文献
55.
Claudio Babiloni Giuliano Binetti Emanuele Cassetta Gloria Dal Forno Claudio Del Percio Florinda Ferreri Raffaele Ferri Giovanni Frisoni Koichi Hirata Bartolo Lanuzza Carlo Miniussi Davide V Moretti Flavio Nobili Guido Rodriguez Gian Luca Romani Serenella Salinari Paolo M Rossini 《Clinical neurophysiology》2006,117(2):252-268
OBJECTIVE: The present study tested the hypothesis that cortical electroencephalographic (EEG) rhythms. change across normal elderly (Nold), mild cognitive impairment (MCI), and Alzheimer's disease (AD) subjects as a function of the global cognitive level. METHODS: Resting eyes-closed EEG data were recorded in 155 MCI, 193 mild AD, and 126 age-matched Nold subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. RESULTS: Occipital delta and alpha 1 sources in parietal, occipital, temporal, and 'limbic' areas had an intermediate magnitude in MCI subjects compared to mild AD and Nold subjects. These five EEG sources presented both linear and nonlinear (linear, exponential, logarithmic, and power) correlations with the global cognitive level (as revealed by mini mental state examination score) across all subjects. CONCLUSIONS: Cortical EEG rhythms change in pathological aging as a function of the global cognitive level. SIGNIFICANCE: The present functional data on large populations support the 'transitional hypothesis' of a shadow zone across normality, pre-clinical stage of dementia (MCI), and AD. 相似文献
56.
Stefano Tamburin Antonio Fiaschi Domenico Idone Piergiorgio Lochner Paolo Manganotti Giampietro Zanette 《Movement disorders》2003,18(11):1316-1324
Hyperexcitability of the motor system has been reported in Parkinson's disease (PD). We evaluate how cutaneous afferents modulate motor excitability in PD patients and whether abnormal modulation is correlated to parkinsonian symptoms. Digital stimulation causes abnormal enhancement of motor responses in patients. This effect may be one of the features of motor hyperexcitability in PD. Cutaneomotor hyperexcitability correlates with clinical scores, suggesting that abnormal processing of cutaneous inputs might contribute to the pathogenesis of parkinsonian symptoms. 相似文献
57.
Pathologic changes during acute Q fever: influence of the route of infection and inoculum size in infected guinea pigs. 总被引:3,自引:1,他引:2 下载免费PDF全文
As assessed by both standard histological staining and immunochemistry, intraperitoneal inoculation of C. burnetii in guinea pigs led to pathologic changes mainly in the liver, whereas intranasal inoculation led to pathologic changes mainly in the lungs. Myocarditis and positive blood cultures were observed only in those animals which received the highest inoculum. We therefore conclude that both the route of infection and the size of the inoculum influence clinical expression in acute Q fever. 相似文献
58.
Laipcarpine (LC), a pyorrolizidine alkaloid, is able to inducea series of chronic and progressive lesions in rat liver, includingalong-lasting block in the cell cycle, the appearance of enlargedhepatocytes (megalocytosis), fibrosis, cirrhosis and malignantneoplasms. In this study the effect of transplantation of normalhepatocytes on the development of LC (80 µmol/kg i.p.).Four weeks later all animals were subjected to 2/3 paroticlhepatectomy (PH). In addition, at the time of PH one group ofrats were transplanted with normal hepatocytes isolated froma syngeneic donor (106 cells/rat via the portal vein), whilethe other group received only the culture medium. All rats werekilled 14 weeks after the operation. Grossly, the liver of ratsexposed to LC followed by PH with no transplantation of normalhepatocytes was small in size (% liver wt/body wt 1.66 ±0.08) and exhibited a few whitish nodules. Histologically, 相似文献
59.
The aim of this study was to determine whether the use of bactericidal coatings or immersion in antibiotic solution reduces or prevents bacterial adhesion onto ureteric stents. Precut segments of full silicone, silver-coated and hydrogel-coated ureteric stents were incubated with two uropathogenic bacterial strains with and without previous immersion in antibiotic solution. Tobramycin, ceftriaxone and ciprofloxacin solutions were used, as these antibiotics are commonly administered for the prophylaxis and treatment of urinary tract infection (UTI). Microbiological analysis showed that immersion of ureteric stents in ceftriaxone and ciprofloxacin yielded a significant reduction of bacterial adhesion, whereas immersion in tobramycin did not. The surface material of the stents had no direct influence on bacterial adhesion. In this experimental study, neither the silver nor the hydrogel coat reduced bacterial adhesion onto ureteric stents whereas immersion in a suitable antibiotic solution significantly reduced and even prevented this phenomenon, probably due to the adhesion of the antibiotic onto the stent surface. Prevention of bacterial adhesion onto ureteric stents is essential to reduce the risk of UTI in connection with these devices. 相似文献
60.
J-H. Longeville P. De La M. Hall P. Dolan A. W. Holt P. E. Lillie J. A. R. Williams R. T. A. Padbury 《HPB surgery》1997,10(3):159-162
We describe a case of giant cavernous haemangioma of the liver with disseminated intravascular coagulopathy (Kasabach-Merritt syndrome) which was cured by orthotopic liver transplant.A 47 year old man presented with bleeding and tender massive hepatomegaly after tooth extraction. Investigations showed disseminated intravascular coagulopathy and a giant hepatic haemangioma involving both lobes of the liver. Initial treatment failed to resolve the coagulopathy and liver resection was attempted. At laparotomy the turnout was unresectable and the only option for cure was to offer a liver transplantation. The orthotopic liver transplant was performed 20 days after initial laparotomy. Subsequently, all coagulation parameters returned to normal and the patient remains well after 12 months. Orthotopic liver transplant can be considered for giant hepatic haemangioma with Kasabach-Merritt syndrome when resection is necessary and a partial hepatectomy is not technically feasible. 相似文献