首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4383篇
  免费   118篇
  国内免费   15篇
耳鼻咽喉   145篇
儿科学   182篇
妇产科学   209篇
基础医学   273篇
口腔科学   241篇
临床医学   389篇
内科学   876篇
皮肤病学   107篇
神经病学   239篇
特种医学   168篇
外科学   972篇
综合类   75篇
一般理论   1篇
预防医学   143篇
眼科学   175篇
药学   177篇
中国医学   5篇
肿瘤学   139篇
  2024年   9篇
  2023年   22篇
  2022年   32篇
  2021年   76篇
  2020年   59篇
  2019年   75篇
  2018年   87篇
  2017年   66篇
  2016年   94篇
  2015年   92篇
  2014年   119篇
  2013年   165篇
  2012年   270篇
  2011年   294篇
  2010年   156篇
  2009年   139篇
  2008年   330篇
  2007年   412篇
  2006年   406篇
  2005年   388篇
  2004年   286篇
  2003年   246篇
  2002年   232篇
  2001年   118篇
  2000年   97篇
  1999年   87篇
  1998年   13篇
  1997年   17篇
  1996年   9篇
  1995年   10篇
  1994年   5篇
  1993年   4篇
  1992年   26篇
  1991年   18篇
  1990年   18篇
  1989年   4篇
  1988年   3篇
  1987年   2篇
  1986年   5篇
  1985年   4篇
  1982年   2篇
  1977年   2篇
  1974年   3篇
  1972年   2篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
排序方式: 共有4516条查询结果,搜索用时 15 毫秒
41.
BACKGROUND: Lipoprotein(a) [Lp(a)] is an important risk factor in the pathogenesis of coronary artery disease because of its thrombogenic and atherogenic properties. Lp(a) also displays another property by acting as an acute phase reactant. METHODS: In this work, the study group consisted of 20 male patients having coronary artery bypass under cardiopulmonary bypass (CPB). Preoperative and postoperative levels of plasma total cholesterol, triglyceride, apolipoprotein A1 (Apo A1), apolipoprotein B (Apo B), alpha-1 antitrypsin (a1-AT), alpha-2 macroglobulin (alpha 2-MG), alpha-1 acid glycoprotein (alpha 1-AG), Lp(a) were measured in all patients one day before and after the 1st, 2nd, 4th, and 10th days of CPB. RESULTS: It was observed that the levels of Lp(a) levels gradually reached the preoperative levels at the 10th postoperative day period. Observed change of the Lp(a) levels was similar to that of the other acute phase proteins which are synthesized and released from liver. In contrast, alpha 2-MG has shown different behaviour in terms of operative values. The changes observed for all these 3 parameters were found to be statistically significant (p<0.01). CONCLUSIONS: The data has indicated that Lp(a) levels show similar progress with alpha 2-MG levels. It can be concluded that serum levels of Lp(a) after coronary arterial bypass decrease depending upon several factors and reach basal levels at the end of a 10 day-period of postoperation. The main cause for this decrease might result from the contact of blood with foreign surfaces of the heart-lung machine.  相似文献   
42.
Procalcitonin (PCT) is increasingly recognised as an important diagnostic parameter in clinical evaluation of the critically ill. This prospective study was designed to investigate PCT as a diagnostic marker of infection in critically ill patients with sepsis. Eighty-five adult ICU patients were studied. Four groups were defined on the basis of clinical, laboratory and bacteriologic findings as systemic inflammatory response syndrome (SIRS) (n = 10), sepsis (n = 16), severe sepsis (n = 18) and septic shock (n = 41). Data were collected including C-reactive protein (CRP), PCT levels and Sequential Organ Failure Assessment and Acute Physiology and Chronic Health Evaluation II scores on each ICU day. PCT levels were significantly higher in patients with severe sepsis and septic shock (19.25 +/- 43.08 and 37.15 +/- 61.39 ng/ml) than patients with SIRS (0.73 +/- 1.37 ng/ml) (P < 0.05 for each comparison). As compared with SIRS patients, plasma PCT levels were significantly higher in infected patients (21.9 +/- 47.8 ng/ml), regardless of the degree of sepsis (P < 0.001). PCT showed a higher sensitivity (73% versus 35%) and specificity (83% versus 42%) compared to CRP in identifying infection as a cause of the inflammatory response. Best cut-off levels were 1.31 ng/ml for PCT and 13.9 mg/dl for CRP. We suggest that PCT is a more reliable marker than CRP in defining infection as a cause of systemic inflammatory response.  相似文献   
43.
Secondary septorhinoplasty often requires a large amount of tissue, and autogenous costal cartilage is one type of grafting material that can be used in these cases. In this study, 20 patients with severe nasal deformity received autogenous costal cartilage grafts. Nineteen of the 20 cases were revisions. Costal cartilage grafts were used for structural and nonstructural purposes in these patients. Follow-up ranged from 8 to 32 months. The complications included 1 patient with early wound infection and 3 with minor warping. There were no problems with graft resorption or extrusion. Other than temporary pain, there were also no complications at the donor sites. We conclude that the autogenous costal cartilage graft is an outstanding material for volume filling and structural support when large amounts of tissue are needed in septorhinoplasty.  相似文献   
44.

Background

Biliary complications are important during liver transplantation because of their effect on recipient and graft survival, incidence, and the long treatment period. These complications are associated with 50% morbidity and 30% mortality rates in recent studies. One of the most important reasons for biliary anastomosis complications is arterial ischemia. We present the results of our telescopic biliary anastomosis technique performed on the mucosa of the main biliary duct.

Patients and Methods

Fifty-six cases of telescopic biliary reconstruction were performed in 203 patients during 2015. Fifty cases and 52 patients who underwent standard reconstruction were chosen and compared. All patients had been scanned retrospectively. Statistical analyses were conducted with χ2 and Mann-Whitney U tests for the complications that occurred during the first 3 months. A P value <.05 was considered significant.

Results

No clinical or demographic differences were detected between the groups. About 90% of both groups were living donor liver transplantation cases. Five (10%) anastomotic leaks occurred in telescopic reconstruction group (n = 50), and 13 (25%) occurred in the standard reconstruction group (n = 52; P < .05).

Conclusion

The arterial blood supply is better if the biliary anastomosis is made on the mucosal side of the main biliary duct. Early period anastomotic leaks may decrease significantly.  相似文献   
45.
The objectives of this study are to determine risk factors associated with deep sternal wound infections (DSWIs) following cardiac surgery, and to describe their impact on long-term survival. Data was obtained from a departmental database. Analysis included 7,978 consecutive patients who underwent cardiac surgery between 1997 and 2003. To identify risk factors for DSWI, regression analysis was performed. The probability scores obtained from logistic regression were used for propensity analysis of 2 groups. Kaplan-Meier analysis with log-rank test and Cox proportional hazard models were then used in survival analysis. DSWI developed in 123 of 7,978 patients (1.5%). Preoperative predictors of DSWI were body mass index >30 kg/m(2) (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1 to 2.4; P < 0.05), diabetes mellitus (OR, 2.4; 95% CI, 1.6 to 3.4; P < 0.001), urgent operation (OR, 1.7; 95% CI, 1.2 to 2.6; P < 0.05), smoking history within past year (OR, 2.7; 95% CI, 1.5 to 4.9; P < 0.001), smoking history within past 2 weeks (OR, 2.6; 95% CI, 1.5 to 4.5; P < 0.001), and a history of stroke (OR, 1.9; 95% CI, 1.1 to 3.1; P < 0.005). In addition, total length of hospital stay (OR, 1.01; 95% CI, 1.01 to 1.02; P < 0.05) and sepsis and/or endocarditis following surgery (OR, 5.1; 95% CI, 2.9 to 9.0; P < 0.001) were also predictive of DSWI. Patients with DSWI had a prolonged total length of hospital stay (40.3 days versus 16.1 days; P < 0.001), and higher 30-day mortality (1.6% versus 7.3% in DSWI group, P < 0.05). There were no differences between groups in 4-year and 8-year survival rates, with 77.2% and 61.8%, respectively, in patients with DSWI compared with 78.0% and 67.5% in patients without DSWI (P = 0.16). After adjustments for preoperative, intraoperative, and postoperative factors, the adjusted hazard ratio of long-term mortality for patients with DSWI was 0.9 (95% CI, 0.6 to 1.2, P = 0.39). Though DSWIs are associated with increased early mortality, patients undergoing cardiac surgery complicated by DSWI do not experience worse long-term survival.  相似文献   
46.
BACKGROUND: To evaluate the effect of povidone-iodine liposome hydrogel on colonic anastomosis. METHODS: 70 Wistar-Albino male rats were randomly divided into seven groups. The left colon was transected and end-to-end anastomosis was performed. PVP-I liposome hydrogel was applied around the anastomoses in groups 2 and 5. Colonic bursting pressures and tissue hydroxyproline contents were measured on postoperative days 3 and 7. RESULTS: PVP-I application did not cause any difference in the bursting pressures on postoperative day 3, but anastomotic strength was significantly increased by the use of PVP-I on postoperative day 7. The use of PVP-I liposome hydrogel had no effect on the level of perianastomotic hydroxyproline on postoperative day 3 but had positive effects on postoperativeday 7. CONCLUSIONS: We concluded that the beneficial effects of PVP-I liposome hydrogel might be due to the combination of broad-spectrum antimicrobial activity of PVP-I with the drug delivery properties and moisturizing molecular film effects of the liposome hydrogel.  相似文献   
47.
Nephrotoxicity is a major complication of acetaminophen (APAP), a widely used analgesic and antipyretic drug, and there is no specific treatment for APAP-induced renal damage. It has been reported that reactive oxygen metabolites or free radicals are important mediators of APAP toxicity. In this study, the protective role of melatonin (MLT) on APAP-induced nephrotoxicity was investigated in rats. For this purpose, nephrotoxicity was induced in male Wistar albino rats by intraperitoneal (i.p.) administration of a single dose of 1,000 mg/kg APAP. Some of these rats also received i.p. melatonin (10 mg/kg) 20 min after administration of APAP. The rats were sacrificed 24 h after administration of APAP. Urea and creatinine levels were measured in the blood, and levels of malondialdehyde (MDA) and glutathione (GSH), and glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) activity were determined in renal tissue. Serum urea and creatinine levels increased significantly as a result of APAP nephrotoxicity. A significant increase in MDA and decreases in GSH level and GSH-Px, CAT, and SOD activity indicated that APAP-induced renal damage was mediated through oxidative stress. Significant beneficial changes were noted in serum and tissue oxidative stress indicators in rats treated with MLT. These biochemical observations were supplemented by histopathological examination of kidney sections, which revealed that MLT also reduced the severity of APAP-induced histological alterations in the kidney. These results indicate that administration of APAP causes oxidative stress to renal tissue and that MLT protects against the oxidative damage associated with APAP.  相似文献   
48.
The metabolic syndrome (MS) is a known cardiovascular risk factor in the general population and a common problem among renal transplant recipients. This study investigated whether MS after renal transplantation affected long-term graft function.We included 112 transplants at our center between 2000 and 2002. We excluded patients with the presence of pretransplant diabetes or nonstable renal function at 1 year after transplantation. We evaluated parameters such as demographic features, medications, smoking history, body mass index, daily proteinuria, blood pressure, number of HLA mismatches, number of acute rejection episodes, delayed graft function, and laboratory parameters. Patients were followed for a mean of 69.86 ± 21.94 months. The prevalence of MS was determined using the National Cholesterol Education Program—Adult Treatment Panel III criteria.At 1 year after transplant, 28.6% of subjects had MS, whereas only 10.7% had MS before transplantation. Among 27.7% of patients graft failure had occurred during the follow-up; MS was more frequent among these individuals compared with those displaying stable renal function (51.6% vs 19.8%; P = .002). Older donor age, delayed graft function, acute rejection episodes, smoking history, MS, proteinuria, serum creatinine level, and C-reactive protein were associated with graft failure. Upon multivariate Cox regression analysis, patients with MS at 1 year after transplantation showed an increased risk for graft failure (relative risk, 0.22; 95% confidence interval, 0.06-0.75; P = .016). Older donor age and proteinuria level were other independent risk factors for graft failure.The MS was a prominent risk factor for graft failure. Because MS is a cluster of modifiable risk factors, early identification of patients at risk and intervention in due time may improve graft survival.  相似文献   
49.
F. Ersoz  S. Arikan  O. Ozcan  E. Sentatar 《Hernia》2009,13(5):565-567
Small bowel perforation caused by direct blunt trauma to an inguinal hernia has rarely been reported. In this report, we present a patient with terminal ileum perforation after direct blunt trauma to an inguinal hernia region. Both perforation and hernia repair were managed surgically in the same stage. This case demonstrates that leaving an inguinal hernia unrepaired may lead to dangerous outcomes, such as intestinal strangulation and perforation. Inguinal hernias with intestinal perforation need urgent surgical intervention. It is possible to repair the intestinal perforation and inguinal hernia in the same operation.  相似文献   
50.
Bozkurt G  Ziyal IM  Akbay A  Dal D  Can B  Ozcan OE 《Acta neurochirurgica》2005,147(1):99-100; discussion 100
'Silk cocoon' appearance on spinal angiography is pathognomonic to differentiate paragangliomas from several vascular tumors and malformations of cauda-filar region.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号