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   1470篇
  免费   45篇
  国内免费   8篇
耳鼻咽喉   35篇
儿科学   102篇
妇产科学   60篇
基础医学   75篇
口腔科学   70篇
临床医学   112篇
内科学   274篇
皮肤病学   28篇
神经病学   74篇
特种医学   58篇
外科学   408篇
综合类   22篇
一般理论   1篇
预防医学   28篇
眼科学   47篇
药学   53篇
中国医学   6篇
肿瘤学   70篇
  2023年   14篇
  2022年   19篇
  2021年   27篇
  2020年   19篇
  2019年   29篇
  2018年   20篇
  2017年   23篇
  2016年   46篇
  2015年   50篇
  2014年   57篇
  2013年   102篇
  2012年   110篇
  2011年   97篇
  2010年   71篇
  2009年   66篇
  2008年   103篇
  2007年   119篇
  2006年   103篇
  2005年   99篇
  2004年   107篇
  2003年   81篇
  2002年   78篇
  2001年   12篇
  2000年   9篇
  1999年   8篇
  1998年   4篇
  1997年   7篇
  1996年   6篇
  1995年   9篇
  1994年   5篇
  1993年   7篇
  1992年   4篇
  1991年   1篇
  1990年   5篇
  1989年   1篇
  1987年   1篇
  1986年   2篇
  1967年   1篇
  1908年   1篇
排序方式: 共有1523条查询结果,搜索用时 15 毫秒
101.
BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a rare disease that is fatal if it is not treated. Therapeutic plasma exchange (TPE) has resulted in excellent remission and survival rates in TTP patients. MATERIAL AND METHODS: We describe our experience with 52 TTP patients treated with TPE during the past eight years (65% of the patients were females; patient median age=34 years, range: 17-73). TPE was carried out 1-1.5 times plasma volume. Fresh frozen plasma (FFP) or cryosupernatant plasma (CSP) was used as the replacement fluid. TPE was performed daily until normalization of serum LDH and recovery of the platelet count to >150 x 10(9)/dL; TPE was then slowly tapered. Clinical, laboratory data, the number of TPE, other given therapy modalities, treatment outcomes and survival rate were evaluated retrospectively. RESULTS: Overall response (OR) and complete response (CR) rates were 77% and 60%, respectively. Response was excellent in 82.8% of the patients with primary TTP among whom 74.2% were CR. Additionally, there were statistical differences in terms of CR rate between patients with primary TTP and secondary TTP (74.2% vs. 29.4%; p=0.005). OR and CR rates were 79% and 57.9% in patients on TPE alone and 75.8% and 60.6% in patients on TPE+prednisolone, respectively (p=1 and p=0.8). Additionally, there were no statistical differences in terms of OR and CR rates between patients on TPE with FFP and CSP (p=0.25 and p=0.16, respectively). The presence of fever and the number of TPE were statistically important factors influencing the probability of response in multivariate logistic regression analysis (p<0.01 and p<0.01, respectively). Additionally, in multivariate Cox's regression analysis, the probability of survival was higher in patients who were responsive to treatment compared to patients who were unresponsive (p<0.001). CONCLUSION: TPE is an effective treatment for primary TTP; however, it may be used as adjunctive therapy for secondary TTP until it is under control. The addition of steroids to TPE had no advantage compared to TPE alone. CSP as replacement fluid is not superior compared to FFP. Fever appears to be a bad prognostic indicator. Therefore, prolonged treatment with TPE may be needed in patients with fever.  相似文献   
102.
BACKGROUND: Diagnosis of tuberculous pleuritis is difficult because of its nonspecific clinical presentation and decreased efficiency of traditional diagnostic methods. We investigated the use of procalcitonin (PCT) concentration in tuberculous pleuritis diagnosis. METHODS: A prospective clinical study was performed with two different patient groups. A total of 28 patients were included: 18 with tuberculosis and 10 with nontuberculous pleurisy. Serum and pleural fluid PCT concentrations were evaluated before treatment. RESULTS: Serum and pleural fluid PCT concentrations were statistically different between tuberculous and nontuberculous pleurisy groups (P = 0.012 and P = 0.004, respectively), even though they were not elevated in relation to the cut-off level of 0.5 ng/mL. A positive and significant correlation was detected between serum and pleural fluid PCT levels (r = 0.49, P = 0.008). Diagnostic specificity and sensitivity values for serum and pleural fluid PCT in discriminating tuberculous from nontuberculous pleurisy were 80% and 72.2%, and 90% and 66.7% at the 0.081 and 0.113 ng/mL cut-off values, respectively. CONCLUSION: Relative to the current cut-off level of 0.5 ng/mL, PCT concentration is not a useful parameter for the diagnosis of tuberculous pleurisy. Because there were PCT levels in patients with tuberculous pleurisy that were below the current cut-off level but were significantly different from those of the nontuberculous group, the use of PCT should be further investigated.  相似文献   
103.
The myocardial performance index (MPI) reflects global ventricular function. Chronic hypervolemia and uremia may negatively affect the myocardium of both ventricles. The aims of this study were to investigate how chronic renal failure (CRF) affects biventricular MPI and to determine whether preload reduction by hemodialysis (HD) affects left ventricular MPI (LVMPI) and right ventricular MPI (RVMPI) in CRF. Twenty-one patients with CRF (group 1) were examined 1 hour before and 1 hour after an HD session and 1 7 healthy control patients (group 2) were examined once by echocardiography. The MPI for each ventricle was calculated as the sum of isovolumic time intervals divided by the ejection time. Before HD, the LVMPI of group 1 was similar to that in group 2 (P≫.05), but the RVMPI of group 1 was significantly higher (P=.007). After the HD session, LVMPI and RVMPI remained unchanged (P>.05 for both). The LVMPI and RVMPI were not correlated either before or after HD in group 1 (P>.05 for both), whereas they were correlated in group 2 (r= 0.671, P=.003). Chronic renal failure causes isolated RV dysfunction, as reflected by increased RVMPI values. Preload reduction by HD does not affect LVMPI or RVMPI. Patients with CRF also do not exhibit the correlation of LVMPI and RVMPI that is observed in healthy individuals.  相似文献   
104.
Liquefied petroleum gas (LPG), which is used as a type of fuel, is stored as a liquid under high pressure in tanks. Immediate and sudden explosion of these tanks can release a large amount of gas and energy into the environment and can result in serious burns. In this study, the cases of 18 patients injured due to LPG burns in five incidents were examined, along with their epidemiologic features. The authors also investigated the causes of the LPG tank explosions. Inhalation injury was present in 11 cases with varying degrees of severity, and 7 patients subsequently required mechanical ventilation. The explosions resulted from weakening of the tank wall (n = 2), crash impact (n = 2), and gas leakage from the tank (n = 1). LPG-powered cars are becoming more popular because of their lower operational costs. However, LPG tanks can be hazardous in the event of a tank explosion. Burns caused by explosions of the LPG tanks in cars have significant mortality and morbidity. This danger must be taken into account and public awareness must be increased.  相似文献   
105.
End-stage renal disease is closely associated with changes in bone and mineral metabolism. In recent times, osteoporosis has become important among hemodialysis (HD) patients. In this study, the investigators sought to evaluate the relationship between bone mineral density (BMD) and biochemical markers of bone turnover among HD patients. A total of 70 uremic patients on a maintenance HD program for at least 1 y were enrolled in the study. All patients were treated with conventional bicarbonated HD for 5 h through the use of low-flux hollow-fiber dialyzers. Bone densitometry was measured by dual energy x-ray absorptiometry in the lumbar spine (LS) and the femoral neck (FN). BMD was classified according to World Health Organization criteria on the basis of BMD T scores. Biochemical bone turnover markers such as calcium, phosphorus, ionized calcium, intact parathyroid hormone, alkaline phosphatase, plasma bicarbonate, blood pH, serum albumin, and hematocrit levels were measured before the HD session in the morning. Male patients (n=37; 52.9%; mean age, 46.2+/-17.0 y) were assigned to a single study group, and female patients (n=33; 47.1%; mean age, 44.0+/-13.1 y) to another. Mean duration of HD treatment was 33.7+/-28.5 mo in females and 33.0+/-26.0 mo in males. Among all patients, BMD T scores in the osteopenia/osteoporosis range were observed at the LS in 58 patients (82.8%) and at the FN in 45 patients (64.3%). According to BMD measurements in FN T score, 10% of patients (n=7) were osteoporotic, 54.3% (n=38), osteopenic, and 35.7% (n=25), normal. On the other hand, in LS T score, the results were 47.1% (n=33) osteoporotic, 35.7% (n=25), osteopenic, and 17.1% (n=12), normal. No statistically significant association was found in osteopenia/osteoporosis between sexes according to FN and LS T score (P=.542, P=.267, respectively). No significant relationship was noted between BMD and biochemical markers of bone turnover. A positive correlation was found between FN T scores of BMD and age (r=.413, P=.000). BMD T scores within the range of scores for osteopenia/osteoporosis were observed in 78.5% of patients at the LS and in 58.5% of patients at the FN. The investigators concluded that no correlation could be found between markers of bone turnover and bone mass measurements in both skeletal regions. LS T score results were worse than FN T score results. Elevated alkaline phosphastase levels combined with high intact parathyroid hormone levels are predictive of renal osteodystrophy but not of adynamic bone disease/osteoporosis.  相似文献   
106.
Vogt-Koyanagi-Harada (VKH) disease is a rare inflammatory ocular disorder that is characterized by bilateral granulomatous panuveitis, neuropathy, and aseptic meningitis, along with various extraocular manifestations. VKH disease has been reported to be associated with various immune disorders. In this report, a case of VKH disease is presented that is associated with mesenteric vascular disease and intestinal necrosis, with an emphasis on the fact that this is the first case documented in the literature of both diseases occurring simultaneously.  相似文献   
107.
Rhabdomyosarcoma (RMS) is rare disease in adults (age >or= 16 years). The data from randomized prospective trials are scarce; the clinical outcome of these patients seems poor with the currently available treatment strategies. In this study, we report a single institution's experience in the treatment of adult RMS. We reviewed the medical records of patients with RMS who were >or= 16 years and have been treated in our institution between 1988 and 2003 retrospectively. We analyzed the survival outcome of these patients and the prognostic impact of clinical/pathological factors on their survival. In total, 23 patients with RMS were identified. Median age was 26 years (range, 16-72 years). Majority of patients were male (n: 17, 73.9%), and had large tumors (>or= 5 cm, n: 13, 56.5%), localized disease (N0, M0, n: 12, 52.2%), and embryonal histology (n: 10, 43.5%). Median overall survival was 31.3 months, and the 3-year progression-free survival and overall survival rates were 19.9% and 34.94%, respectively. Patients with smaller tumors (< 5 cm) (p < 0.04), local disease (p < 0.01), and normal lactic dehydrogenase (LDH) level (p < 0.01) at the time of diagnosis were found to have better survival outcome. The tumor size, serum LDH level, and metastatic disease at the time of diagnosis are potential predictors of outcome in patients with adult RMS. Adult RMS is an aggressive disease with poor survival despite treatment. The data from prospective, randomized multicenter trials are necessary in order to improve the clinical outcome of adult RMS patients.  相似文献   
108.
The relationship between cardiac shape and the age of patients with hypertrophic cardiomyopathy (HCM) has been established, and echocardiography has been accepted as the best method to quantitate ventricular cavity geometry. Recently, real-time three-dimensional volumetric data have demonstrated that children and young, middle-aged, and elderly patients with HCM have different morphologic and prognostic characteristics. This review discusses the importance of phenotypic expression and describes secondary factors that may affect ventricular cavity geometry during the progression of HCM.  相似文献   
109.
BACKGROUND: Hepatitis B (HBV) and C (HCV) viruses are the most common viruses that cause viral infections among the hemodialysis patients. OBJECTIVES: To assess the prevalence of HBV and HCV in predialytic chronic kidney disease (CKD) patients. DESIGN: A cross-sectional study. SUBJECTS: 171 consecutive predialytic CKD patients. MEASUREMENTS: Third-generation micro-ELISA assay was used for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core (anti-HBc) and surface antibody (anti-HBs), secretory form of hepatitis B envelop antigen (HBeAg), antibody to secretory form of hepatitis B envelop antigen (anti-HBe), and ELISA for antibody to hepatitis C virus (anti-HCV). RESULTS: The main causes of CKD were 29.8% diabetic nephropathy, 19.9% chronic glomerulonephritis, 16.3% hypertensive nephrosclerosis, 14.0% unknown, 5.3% amyloidosis, 4.7% autosomal-dominant polycystic kidney disease, 4.1% chronic tubuluointerstitial nephritis, 3.5% malignancies, 1.7% benign prostatic hypertrophy, 0.6% Alport syndrome. The seroprevalence of hepatitis was: HBsAg 10.5%, anti-HBc 36.8%, anti-HBs 28.7%, HBeAg 5.3%, anti-HBe 32.7%, anti-HCV 7% and HBsAg+anti-HCV 0.6%. CONCLUSIONS: The seroprevalence of HBsAg and anti-HCV among predialytic CKD patients was similar to our patients in hemodialysis program.  相似文献   
110.
Due to current advances and growing experience in the management of coronavirus Disease 2019 (COVID-19), the outcome of COVID-19 patients with severe/critical illness would be expected to be better in the second wave compared with the first wave. As our hospitalization criteria changed in the second wave, we aimed to investigate whether a favorable outcome occurred in hospitalized COVID-19 patients with only severe/critical illness. Among 642 laboratory-confirmed hospitalized COVID-19 patients in the first wave and 1121 in the second wave, those who met World Health Organization (WHO) definitions for severe or critical illness on admission or during follow-up were surveyed. Data on demographics, comorbidities, C-reactive protein (CRP) levels on admission, and outcomes were obtained from an electronic hospital database. Univariate analysis was performed to compare the characteristics of patients in the first and second waves. There were 228 (35.5%) patients with severe/critical illness in the first wave and 681 (60.7%) in the second wave. Both groups were similar in terms of age, gender, and comorbidities, other than chronic kidney disease. Median serum CRP levels were significantly higher in patients in the second wave compared with those in the first wave [109 mg/L (interquartile range [IQR]: 65–157) vs. 87 mg/L (IQR: 39–140); p < 0.001]. However, intensive care unit admission and mortality rates were similar among the waves. Even though a lower mortality rate in the second wave has been reported in previous studies, including all hospitalized COVID-19 patients, we found similar demographics and outcomes among hospitalized COVID-19 patients with severe/critical illness in the first and second wave.  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