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   845篇
  免费   36篇
  国内免费   4篇
耳鼻咽喉   33篇
儿科学   40篇
妇产科学   31篇
基础医学   54篇
口腔科学   14篇
临床医学   64篇
内科学   178篇
皮肤病学   20篇
神经病学   50篇
特种医学   44篇
外科学   190篇
综合类   12篇
预防医学   24篇
眼科学   41篇
药学   36篇
中国医学   1篇
肿瘤学   53篇
  2023年   9篇
  2022年   14篇
  2021年   24篇
  2020年   24篇
  2019年   28篇
  2018年   32篇
  2017年   23篇
  2016年   23篇
  2015年   27篇
  2014年   22篇
  2013年   50篇
  2012年   71篇
  2011年   91篇
  2010年   31篇
  2009年   25篇
  2008年   58篇
  2007年   47篇
  2006年   60篇
  2005年   45篇
  2004年   34篇
  2003年   42篇
  2002年   44篇
  2001年   17篇
  2000年   11篇
  1999年   11篇
  1998年   2篇
  1997年   2篇
  1996年   3篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1987年   1篇
  1986年   1篇
  1982年   1篇
  1977年   1篇
  1975年   1篇
  1974年   2篇
  1971年   1篇
  1970年   1篇
  1968年   2篇
  1966年   1篇
排序方式: 共有885条查询结果,搜索用时 31 毫秒
81.
82.
BACKGROUND: Even with a functioning gastrointestinal tract, it is not always easy to initiate oral feeding in some neurosurgical patients because of their persistently depressed neurologic status or severe lower cranial nerve palsies. Percutaneous endoscopic gastrostomy (PEG) may be required for long-term feeding in these patients. The purpose of the present study is to report our experience with PEG chosen for establishing an enteral route in patients of neurosurgical intensive care unit (ICU). METHODS: The outcome and complications of PEG in neurosurgical ICU patients of Marmara University Institute of Neurological Science between January 2001 and November 2006 were retrospectively evaluated. RESULTS: Thirty-one patients, with the median age of 51 years (range, 14-78 years) underwent PEG placement. PEG was placed before the craniotomy in 2 patients and after in 29. Indications for PEG were absent gag reflex in 10 patients and low Glasgow Coma Scale score in 21. Before the PEG tube insertion, 18 patients had enteral nutrition by a nasogastric tube and 10 had parenteral nutrition (PN), with a median duration of 14.5 (range, 4-60) and 12 (range, 7-25) days, respectively. Two patients accidentally pulled out the gastrostomy tubes 10 and 11 days after insertion. Buried bumper syndrome developed in 1 patient. Two patients died 8 and 34 days after the procedure in the neurosurgical ICU. Twenty-nine patients were discharged from the hospital while being fed via the PEG tubes. In 11 patients who were able to resume oral feeding, the tube was removed, with a median interval of 62 (range, 25-150) days. Procedure-related mortality, 30-day mortality, and overall mortality of the patients were 0%, 6.4%, and 45%, respectively. CONCLUSION: PEG is a safe and well-tolerated gastrostomy method for neurosurgical ICU patients with depressed neurologic state or severe lower cranial nerve palsies.  相似文献   
83.

Objectives

To evaluate the role of pentraxin-3 (PTX-3) in determining the presence and severity of coronary atherosclerosis in patients with coronary artery disease (CAD).

Subjects and Methods

Ninety-five patients (77 males and 18 females) who underwent elective coronary angiography were enrolled in this study. Patients with heart failure, renal failure, diabetes and thyroid disease were excluded. The study population was divided into 3 groups: individuals with normal coronary arteries, patients with critical CAD (n = 35) and patients with noncritical CAD (n = 36). The association of PTX-3 levels with the presence and severity of CAD and the number of involved vessels were analyzed.

Results

The mean age was 53.40 ± 10.25 years. The PTX-3 levels were significantly higher in patients with CAD than without CAD (146.48 ± 48.52 vs. 109.83 ± 49.06 pg/ml, p < 0.001). A statistically significant difference was found among the 3 groups regarding the severity of CAD (165.66 ± 49.10, 127.83 ± 40.51 and 109.83 ± 49.06 pg/ml, p < 0.001, respectively). The serum PTX-3 levels in normal arteries were 110.4 ± 48.11 pg/ml, in single-vessel disease 132.35 ± 32.96 pg/ml, in 2-vessel disease 142.57 ± 55.88 pg/ml, in 3-vessel disease 156.07 ± 50.53 pg/ml, and in 3-vessel disease 160.50 ± 30.41 pg/ml. After adjusting for baseline confounders, older age (OR = 1.107, 95% CI = 1.027-1.193, p = 0.008) and higher PTX-3 levels (OR = 1.017, 95% CI = 1.003-1.032, p = 0.021) were detected as significant predictors for the presence of CAD.

Conclusions

Higher PTX-3 levels were associated with the presence of CAD and its increased severity in clinically stable patients. Higher PTX-3 levels may be regarded as a novel diagnostic predictor and may offer therapeutic options in the clinic.Key Words: Coronary angiography, Coronary artery disease, Pentraxin-3  相似文献   
84.

Objective

The aim of the study was to investigate the effect of intragastric balloon therapy on left ventricular function and left ventricular mass in a cohort of morbidly obese patients.

Subjects and Methods

A prospective trial was performed in a cohort of 17 class II and class III morbidly obese individuals. The intragastric balloon was retained in the stomach for an average of 6 months. Conventional and tissue Doppler echocardiography were performed in all patients before and after the procedure.

Results

The mean age of the study participants was 36 ± 10 years (range: 18–55). The mean body mass index was significantly decreased following the intragastric balloon insertion procedure (44 ± 8 vs. 38 ± 5, p < 0.001). The left ventricular mass index and left atrial volume index were significantly decreased following the procedure (112 ± 21 vs. 93 ± 17, p = 0.001 and 20 ± 6 vs. 14 ± 5, p = 0.02, respectfully). In addition, the ratio of mitral peak early diastolic velocity to tissue Doppler-derived peak diastolic velocity and tissue Doppler echocardiography-derived left ventricular myocardial performance index were decreased significantly following the procedure (9.5 ± 1.9 vs. 7.7 ± 1.5, p = 0.002 and 0.57 ± 0.11 vs. 0.46 ± 0.06, p = 0.001, respectively).

Conclusions

Intragastric balloon therapy resulted in significant weight reduction in morbidly obese patients. This weight reduction was associated with improved left ventricular function.Key Words: Obesity, Intragastric balloon therapy, Echocardiography, Tissue Doppler  相似文献   
85.
86.
87.
To date, no randomized study has compared different doses of recombinant human granulocyte colony-stimulating factor (rhG-CSF) following submyeloablative mobilization chemotherapy. Therefore, we evaluated the effect of different doses of rhG-CSF following mobilization chemotherapy on yields of CD34+ peripheral blood stem cells (PBSC). Fifty patients were randomized to receive 8 (n = 25) versus 16 microg/kg/d (n = 25) of rhG-CSF following mobilization chemotherapy. The median number of CD34+ cells collected after 8 microg/kg/d of rhG-CSF was 2.36 x 10(6)/kg (range, 0.21-7.80), compared with 7.99 (2.76-14.89) after 16 microg/kg/d (P < 0.001). Twenty out of 25 (80%) patients in the low-dose and 23 out of 25 (92%) in the high-dose rhG-CSF arm underwent high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT). Median days to white blood cell engraftment in patients mobilized with 8 microg/kg and 16 microg/kg of rhG-CSF were 12 (10-20) and 9 (8-11) respectively (P < 0.001). There was no difference between the two groups regarding the other parameters of peritransplant morbidity: days to platelet engraftment (P = 0.10), number of red blood cell (P = 0.56) and platelet transfusions (P = 0.22), days of total parenteral nutrition requirement (P = 0.84), fever (P = 0.93) and antibiotics (P = 0.77), and number of different antibiotics used (P = 0.58). These data showed that higher doses of rhG-CSF following submyeloablative mobilization chemotherapy were associated with a clear dose-response effect based on the collected cell yields. Based on the parameters of peritransplant morbidity, 8 microg/kg/d was as effective as 16 microg/kg/d except for a rapid neutrophil engraftment in the high-dose arm. Therefore, in routine clinical practice, despite some advantage in the use of higher doses of rhG-CSF, lower doses may be used for PBSC collections following chemotherapy-based mobilization regimens in this cost-conscious era.  相似文献   
88.
OBJECTIVE: The efficacy and the effective dose of levothyroxine suppressive therapy in the treatment of benign thyroid nodules are controversial. In this study, we aimed to determine the response of solitary thyroid nodules to low- or high-level TSH suppression in a placebo-controlled, randomized crossover trial. DESIGN: Forty-nine patients with solitary thyroid nodules on palpation were randomized to high-level and low-level TSH suppression groups. In each group, patients were further randomized to placebo and active levothyroxine subgroups. Patients in each subgroup were crossed over to placebo or active levothyroxine at the end of the first year and were then followed up for an additional year. METHODS: TSH levels were suppressed to 0.4-0.6 mIU/ml and < or = 0.01 mIU/ml in the low-level and high-level TSH suppression groups, respectively. Nodule volumes were measured at baseline and every 6 months after the desired level of TSH was reached if the patients were in the active levothyroxine treatment group or every 6 months if they were in the placebo group. RESULTS: In high-level TSH suppression groups, nodule volume decreased significantly at the end of the active treatment periods (4.99 +/- 2.02 ml vs. 3.20 +/- 1.50 ml, P < 0.01, in Group 1; and 3.72 +/- 1.79 ml to 2.05 +/- 0.64 ml, P < 0.001, in Group 2). In the low-level TSH suppression groups, nodule volume also decreased significantly at the end of the active treatment periods (4.43 +/- 1.76 ml vs. 3.04 +/- 1.32, P < 0.05, in Group 3; and 3.59 +/- 0.89 ml to 2.22 +/- 0.59 ml, P < 0.01, in Group 4). Nodule volumes regained their original volumes during the placebo treatment periods. The percentage decline in clinically relevant nodule volume reduction (> or = 50%) was similar in the low-level and high-level TSH suppression groups. CONCLUSION: Low- and high-level TSH suppression were equally effective in reducing nodule volume and thus, considering the complications of high-level TSH suppression, low-level TSH suppression should be used if one considers levothyroxine suppressive therapy to reduce thyroid nodule size.  相似文献   
89.
Allay  JA; Dumenco  LL; Koc  ON; Liu  L; Gerson  SL 《Blood》1995,85(11):3342-3351
Myelosuppression is the dose-limiting toxicity for nitrosourea chemotherapy. This toxicity predominantly involves modification of the O6 position of guanine with an alkyl moiety. The enzyme responsible for repair of O6-alkylguanine adducts, O6-alkylguanine-DNA alkyltransferase (alkyltransferase), is expressed at low levels in bone marrow (BM) cells. High alkyltransferase expression prevents the cytotoxicity and carcinogenicity of nitrosoureas in several transgenic and in vitro gene transfer models. We used gene transfer using a novel myeloproliferative sarcoma virus (MPSV) based retrovirus (vM5MGMT) to express the human alkyltransferase cDNA (MGMT) in human and murine hematopoietic cells. Transduced K562 cells had very high levels of alkyltransferase expression and significantly increased resistance to 1,3-bis (2- chloroethyl) nitrosourea (BCNU) as compared with untransduced K562 cells. Primary murine BM progenitors showed a high transduction efficiency with vM5MGMT and have increased BCNU resistance in vitro. After BM transplantation with vM5MGMT-transduced BM cells and BCNU treatment of these mice, BM, spleen and thymus had a 10- to 40-fold increase in alkyltransferase expression that persisted for at least 23 weeks posttransplantation. Progenitor cells procured from mice expressing high levels of alkyltransferase also had increased resistance to BCNU. Thus, an MPSV-based retroviral vector transduces mouse and human hematopoietic cells at high efficiency and results in high levels of gene expression both in vitro and in vivo. Overexpression of the alkyltransferase protein may protect hematopoietic progenitors from nitrosourea-induced myelosuppression.  相似文献   
90.
Direct stenting (i.e., stenting without balloon predilation) is a novel approach to the percutaneous treatment of coronary artery lesions. This approach, by reducing aggression to the vessel wall and immediately sealing the dissections created by balloon inflation by the endoprosthesis, may also significantly lower the rate of procedural ischemic complications. Our purpose was to measure cardiac troponin T (cTnT), creatine kinase and its isoform CKMB after apparently successful elective stent implantation with conventional stenting (CS) or direct stenting (DS) and to compare the procedural myocardial injury between these 2 approaches. Enzyme levels were measured before and 16 hours post-procedure. A second-generation commercial ELISA cTnT assay (Boehringer Mannheim Corporation) was used to measure cTnT with a cut-off of 0.1 ng/dl. There was no abnormality in any of the 3 enzymes in either group before the procedure. Although the incidence of cTnT was elevated in 4 of 37 patients (10.8%) in the DS group and in 5 out of 23 patients (21.7%) in the CS group at 16 hours post-procedure, these values did not reach statistical significance (p > 0.05). Creatine kinase and CKMB levels were not elevated in any of the patients. CTnT and CKMB measurements are needed to detect this minor myocardial damage. Randomized studies with larger patient populations should be conducted to compare the two different approaches.  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