全文获取类型
收费全文 | 11373篇 |
免费 | 690篇 |
国内免费 | 73篇 |
专业分类
耳鼻咽喉 | 163篇 |
儿科学 | 406篇 |
妇产科学 | 398篇 |
基础医学 | 1029篇 |
口腔科学 | 360篇 |
临床医学 | 968篇 |
内科学 | 2442篇 |
皮肤病学 | 193篇 |
神经病学 | 546篇 |
特种医学 | 402篇 |
外科学 | 2217篇 |
综合类 | 359篇 |
现状与发展 | 1篇 |
一般理论 | 12篇 |
预防医学 | 710篇 |
眼科学 | 259篇 |
药学 | 915篇 |
中国医学 | 75篇 |
肿瘤学 | 681篇 |
出版年
2023年 | 119篇 |
2022年 | 346篇 |
2021年 | 537篇 |
2020年 | 302篇 |
2019年 | 382篇 |
2018年 | 474篇 |
2017年 | 276篇 |
2016年 | 376篇 |
2015年 | 385篇 |
2014年 | 506篇 |
2013年 | 656篇 |
2012年 | 902篇 |
2011年 | 856篇 |
2010年 | 486篇 |
2009年 | 378篇 |
2008年 | 609篇 |
2007年 | 667篇 |
2006年 | 621篇 |
2005年 | 540篇 |
2004年 | 480篇 |
2003年 | 400篇 |
2002年 | 382篇 |
2001年 | 127篇 |
2000年 | 111篇 |
1999年 | 101篇 |
1998年 | 67篇 |
1997年 | 53篇 |
1996年 | 43篇 |
1995年 | 34篇 |
1994年 | 41篇 |
1993年 | 27篇 |
1992年 | 87篇 |
1991年 | 52篇 |
1990年 | 66篇 |
1989年 | 58篇 |
1988年 | 43篇 |
1987年 | 47篇 |
1986年 | 24篇 |
1985年 | 41篇 |
1984年 | 29篇 |
1983年 | 37篇 |
1982年 | 20篇 |
1980年 | 19篇 |
1979年 | 33篇 |
1978年 | 20篇 |
1977年 | 26篇 |
1976年 | 18篇 |
1974年 | 34篇 |
1973年 | 32篇 |
1972年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Gender-related differences in morbidity and mortality during combined valve and coronary surgery 总被引:1,自引:0,他引:1
Ibrahim MF Paparella D Ivanov J Buchanan MR Brister SJ 《The Journal of thoracic and cardiovascular surgery》2003,126(4):959-964
BACKGROUND: Gender-related differences in morbidity and mortality are well described for coronary artery bypass grafting but are not well understood for combined valve and bypass surgery. METHODS: We reviewed retrospectively the morbidity and mortality of 1570 consecutive patients who underwent combined valve and bypass procedures at the Toronto General Hospital between January 1990 and October 2000. RESULTS: There were 1073 men (68%) and 497 women (32%). The mean ages (+/- 1 SD) of women and men were 69 +/- 9 and 68 +/- 9 years, respectively (P =.02). Of the 1570 total patients, 973 patients (62%) underwent aortic valve and coronary bypass surgery, 481 patients (31%) had mitral valve and coronary bypass operations, and 116 (7%) patients had double or triple valve and coronary bypass operations. Preoperative hypertension (P =.002), diabetes (P =.001), and atrial fibrillation (P =.001) were seen more frequently in women. Body surface area was significantly lower in women (P =.0001). At presentation, more women were in congestive heart failure (69% vs 58%, P =.001) and in New York Heart Association functional class III or IV (25% vs 19%, P =.001). Although there was no difference in the number of women with three or more diseased vessels (32% vs 38%), only 35% of women received three or more grafts compared with 44% of men (P =.001). The use of left internal thoracic grafts, although uncommon in the whole study population (36%), was less common in women than in men (26% vs 41%, P =.001). Multivariable logistic analyses for morbidity and mortality showed female gender to be an independent risk factor. Mitral valve replacement, age, left ventricular dysfunction, New York Heart Association classes III and IV, and association of tricuspid valve disease, diabetes, peripheral vascular disease, and preoperative renal failure were found to be independent risk factors for mortality. CONCLUSION: Female gender is an independent risk factor for combined morbidity and mortality during and after combined valve and coronary bypass surgery. As with isolated coronary artery bypass grafting, women undergoing combined procedures have more premorbid conditions, are more often in heart failure, had an equal incidence of triple vessel disease but received fewer grafts than men, and, therefore, were more frequently incompletely revascularized. 相似文献
102.
T-cell mediated immune responses play a critical role in chronic allograft dysfunction. The complex nature of allograft rejection, particularly with respect to the vast repertoire of alloantigens and their mode of recognition by T cells, presents a major challenge for the design of well-controlled studies into the immunobiology of chronic rejection. The purpose of this study was to develop a rat model with restricted antigenic specificity that develops chronic rejection without any immunologic manipulation to study the T-cell response. PVG.1U allogeneic hearts disparate for one single class I antigen, RT.1A(u), were transplanted into PVG.R8 rat recipients. Grafts from PVG.R8 were used as syngeneic controls. Chronic rejection was studied by histological analysis of the grafted hearts at various time points posttransplantation (20-100 days). Donor specific alloreactive response was studied in a mixed lymphocyte reaction assay. All allografts survived more than 90 days and showed extensive evidence of chronic rejection, which was characterized by interstitial fibrosis, vasculitis, and occlusive myointimal thickening. Chronic rejection was evident by day 20 and most extensive by day 100 posttransplantation. In marked contrast, syngeneic grafts remained free of chronic lesions. Lymphocytes harvested from graft recipients showed a more vigorous proliferative response to allogeneic splenocytes as compared with that of lymphocytes from nai;ve animals. The proliferative response was primarily mediated by CD4(+) T cells recognizing the RT1.A(a) molecule via the indirect pathway. A single class I disparity in this model generates chronic rejection associated with potent CD4(+) T-cell responses induced by the indirect recognition pathway. The use of this antigenically restricted model may facilitate the design of well-controlled studies for the characterization of immune mechanisms responsible for chronic rejection. 相似文献
103.
Sammy Saab Rafik M. Ghobrial Ayman B. Ibrahim Gregg Kunder Francisco Durazo Steven Han Douglas G. Farmer Hasan Yersiz Leonard I. Goldstein Ronald W. Busuttil 《American journal of transplantation》2003,3(9):1167-1172
Hepatitis C (HCV)-positive liver grafts have been increasingly used in patients with decompensated liver disease from HCV because of critical shortage of available organs. Fifty-nine recipients of HCV-positive grafts were matched to patients who received HCV-negative grafts. All recipients were transplanted for HCV liver disease. Matching variables were (1) status, (2) pre-transplant creatinine, (3) recipient age, (4) donor age, (5) warm ischemia time, and (6) year of transplantation. Both unmatched and matched analyses were performed on patient survival, graft survival, and time to HCV recurrence. There was no significant statistical difference in patient, graft, or HCV recurrence-free survival between recipients of HCV-positive and HCV-negative grafts with matched and unmatched analyses (p > 0.05). The 3-year estimates of HCV disease-free survival were 12% (+/- 9%) and 19% (+/- 7%) using HCV-positive and -negative grafts, respectively. The use of HCV-positive grafts in recipients with HCV does not appear to affect patient survival, graft survival, or HCV recurrence when compared with the use of HCV-negative grafts. Our results suggest that HCV-positive grafts can be used in a HCV liver transplant recipient. 相似文献
104.
Siamak?AsgariEmail author Tobias?Engelhorn Anja?Brondics Ibrahim?Erol?Sandalcioglu Dietmar?Stolke 《Neurosurgical review》2003,26(26-4):192-197
Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high. 相似文献
105.
OBJECTIVE: To determine whether antisepsis with povidone-iodine solution applied at the external urethral meatus confers protection against infective complications following transurethral resection of the prostate (TURP) and compare that with antibacterial prophylaxis. METHODS: A total of 167 patients with sterile urine undergoing TURP for benign prostatic hyperplasia (BPH) were prospectively randomized into three groups. Group A, had gauze soaked in saline applied at the urethral meatus (control group). In group B, the gauze was soaked in povidone-iodine instead of saline and group C had a single 1 g i.v. injection of cephradine at induction of anaesthesia with no treatment for the meatus. Bacteraemia, post-operative bacteriuria and other infective complications were compared in the three groups. Associations of bacteriuria at catheter removal and intra-operative bacteraemia with infective complications and with long term bacteriuria were also studied. RESULTS: Bacteriuria rate at catheter removal was not significantly different in the three groups. However, intraoperative bacteraemia and bacterial growth at the external urethral meatus was significantly lower in group C. Bacteriuria at catheter removal was significantly associated with bacterial growth at the meatus but not with long term bacteriuria at 3 months. Bacteriuria at catheter removal could not accurately predict infective complications. CONCLUSION: Post-TURP bacteriuria appears to be preceded by bacterial growth at the external urethral meatus. Antisepsis with povidone-iodine solution application at the meatus does not confer adequate protection against meatal bacterial growth as that obtained by prophylactic antibacterials. Nonetheless, neither antibacterial prophylaxis nor local antisepsis could reduce bacteriuria rate in this study. 相似文献
106.
Eltorai IM Montroy RE Kobayashi M Jakowatz J Guttierez P 《The journal of spinal cord medicine》2002,25(3):191-196
BACKGROUND: The term "Marjolin's ulcer" is now synonymous with malignant transformation, usually ectodermal and rarely mesenchymal, of chronic ulcers, sinus tracts, and burn scars. DESIGN: Literature search and personal experience with 5 patients during a 30-year period in a spinal cord injury center. FINDINGS: Five cases of Marjolin's ulcer diagnosed among approximately 10,000 patients indicate the rarity of the metaplasia. All cases were fatal. CONCLUSIONS: Chronic pressure ulcers of more than 10 years' duration should be biopsied to rule out malignancy, especially with any change in the nature of the ulcer (eg, exuberant granulation and/or bleeding). 相似文献
107.
INTRODUCTION AND OBJECTIVES: Transrectal ultrasound guided biopsy is an essential part in the diagnosis of prostate cancer. Although this procedure is well tolerated by most patients, sometimes it can result in some uneasiness. In this randomised double-blind placebo controlled study, we evaluated the effectiveness of intrarectal lidocaine during TRUS guided biopsy. MATERIALS AND METHODS: 100 consecutive eligible patients who had elevated total prostate specific antigen (tPSA) and/or abnormal digital rectal examination (DRE) were included into this study. Patients were randomised into two groups. Group I received 20 cc of 2% intrarectal lidocaine 20 minutes before transrectal ultrasound guided biopsy and Group II received same amount of serum physiologic. Pain was assessed using a 10 point modified visual analog scale. RESULTS: Mean patient age was 65.5+/-2.5 and 64.5+/-11.5 years, mean tPSA was 12.3+/-3.6 and 11.3+/-1.7 ng/ml, mean biopsy duration was 6.8+/-2.5 and 6.6+/-2.2 minutes, mean pain score during transrectal ultrasound guided biopsy was 4.8+/-2.2 and 4.4+/-2.1 in Groups I and II, respectively. No statistically significant difference was observed with respect to age, tPSA, mean biopsy duration and pain score between these groups. There was only one patient who could not tolerate the procedure at all, and he was paradoxically in the lidocaine group. CONCLUSION: The use of intrarectal lidocaine is not superior to placebo during transrectal prostate biopsy for pain control. 相似文献
108.
Ming Yang Chang Emma Parker Salwa Ibrahim John R Shortland Meguid El Nahas John L Haylor Albert C M Ong 《Nephrology, dialysis, transplantation》2006,21(8):2078-2084
BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited human kidney disease and is caused by germline mutations in PKD1 (85%) or PKD2 (15%). It has been estimated that around 1% of tubular cells give rise to cysts, and cell hyperproliferation has been noted to be a cardinal feature of cystic epithelium. Nevertheless, it is uncertain whether the increase in proliferative index observed is an early or late feature of the cystic ADPKD kidney. METHODS: Two Pkd2 mouse mutants (WS25 and WS183) have been recently generated as orthologous models of PKD2. To determine the effect of Pkd2 dosage on cell proliferation, cyst formation and renal fibrosis, we studied renal tissue from Pkd2(WS25/WS25) and Pkd2(+/-) mice by histological analysis. We also examined the proliferative index in archival nephrectomy tissue obtained from patients with ADPKD and normal controls. RESULTS: The proliferative index of non-cystic tubules in Pkd2 mutant mice as assessed by proliferating cell nuclear antigen and Ki67-positive nuclei was between 1-2%, values 5-10 times higher than control tissue. Similarly, the proliferative index of non-cystic tubules in human ADPKD kidneys was 40 times higher than corresponding controls. In Pkd2 mutant mice, significant correlations were found between the fibrosis score and the mean cyst area as well as with the proliferative index. Of significance, proliferating tubular cells were uniformly positive for polycystin-2 expression in Pkd2(+/-) kidney. CONCLUSION: These results suggest that an increase in cell proliferation is an early event preceding cyst formation and can result from haploinsufficiency at Pkd2. The possible pathogenic link between tubular cell proliferation, interstitial fibrosis and cyst formation is discussed. 相似文献
109.
Ziya Cetinkaya Kazim Esen Ibrahim Hanefi Ozercan Bilal Ustundag Refik Ayten Erhan Aygen 《World journal of emergency surgery : WJES》2006,1(1):37
Background
Ischemia is the most important factor compromises wound healing in colonic anastomosis. Mesenteric vessels are ligated at first while performing colonic resection and following anastomosis. Therefore blood supply of the related segments of colon temporarily interrupted and ischemia can easily occur. This study was carried out to explore whether Bosentan, an endothelin-receptor antagonist, can eliminate vasoconstruction, increase blood flow in the splanchnic area and anastomotic region and therefore possibly facilitate wound healing and prevent intra-abdominal adhesion formation. 相似文献110.