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   1351篇
  免费   71篇
  国内免费   5篇
耳鼻咽喉   50篇
儿科学   51篇
妇产科学   52篇
基础医学   83篇
口腔科学   26篇
临床医学   102篇
内科学   311篇
皮肤病学   10篇
神经病学   69篇
特种医学   91篇
外科学   329篇
综合类   27篇
预防医学   21篇
眼科学   44篇
药学   35篇
中国医学   1篇
肿瘤学   125篇
  2024年   2篇
  2023年   11篇
  2022年   15篇
  2021年   27篇
  2020年   13篇
  2019年   35篇
  2018年   45篇
  2017年   30篇
  2016年   53篇
  2015年   58篇
  2014年   72篇
  2013年   98篇
  2012年   114篇
  2011年   87篇
  2010年   61篇
  2009年   62篇
  2008年   103篇
  2007年   112篇
  2006年   91篇
  2005年   90篇
  2004年   76篇
  2003年   53篇
  2002年   71篇
  2001年   14篇
  2000年   6篇
  1999年   4篇
  1998年   6篇
  1997年   4篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   2篇
  1992年   2篇
  1989年   1篇
  1985年   1篇
  1983年   1篇
  1981年   1篇
  1980年   1篇
排序方式: 共有1427条查询结果,搜索用时 14 毫秒
81.
Durmus M  Ender G  Kadir BA  Nurcin G  Erdogan O  Ersoy MO 《Anesthesia and analgesia》2003,96(5):1336-9, table of contents
Tracheal intubation may be accomplished with remifentanil and a non-opioid IV anesthetic without a muscle relaxant. In this study, we evaluated in double-blinded, prospective, randomized manner the dose requirements for remifentanil with thiopental without muscle relaxant administration to obtain clinically acceptable intubation conditions and cardiovascular responses. After premedication with midazolam 0.03 mg/kg IV, 105 patients were randomized equally to one of three study groups, each receiving the following: remifentanil 2 micro g/kg (Group I), 3 micro g/kg (Group II), and 4 micro g/kg (Group III). Remifentanil was administered over 30 s, and anesthesia was induced with thiopental 5 mg/kg. Tracheal intubation conditions were assessed by the anesthesiologist performing the intubation as: (a) excellent, (b) satisfactory, (c) fair, and (d) unsatisfactory. There were no statistically significant differences among groups regarding to demographic data. Blood pressure and heart rate did not increase in any group after accomplishing intubation. There was a significant improvement in intubation conditions between Groups I and II, I and III, and II and III (P < 0.001). We conclude that remifentanil 4 micro g/kg administered before thiopental 5 mg/kg provided excellent or satisfactory intubation conditions in 94% of patients and prevented cardiovascular responses to intubation. IMPLICATIONS: We evaluated in a double-blinded manner the dose requirements for remifentanil with thiopental without muscle relaxants for obtaining acceptable intubation condition. Our results show that remifentanil 4 micro g/kg administered before thiopental provided excellent or satisfactory intubation condition in 94% of patients.  相似文献   
82.
BACKGROUND AND OBJECTIVES: Serum soluble intercellular adhesion molecule-1 (sICAM-1) and total sialic acid (TSA) are related to the metastatic potential of cancer cells. The purpose of the present investigation was to determine sICAM-1 and TSA levels in colorectal carcinoma and correlate their levels with the cancer stage. METHODS: The sera from 65 patients with colorectal cancer (18 at Dukes' B, 24 at Dukes' C, 23 at Dukes' D) were extracted before treatment. The concentrations of sICAM-1 and TSA were measured by enzyme-linked immunoassay and the thiobarbituric acid method, respectively, and compared with those from a healthy control group (n = 42). RESULTS: Mean serum sICAM-1 and TSA levels were found to be higher in the total patient group than in the control group (P < 0.0001). The concentrations of sICAM-1 and TSA were significantly higher in patients with Dukes' C and Dukes' D. The correlations between sICAM-1 and TSA became more significant as the stage of the disease increased (r = 0.58, P < 0.05 in Dukes' B, r = 0.88, P < 0.01 in Dukes' C and r = 0.81, P < 0.01 in Dukes' D). CONCLUSIONS: The results of this investigation indicate that sICAM-1 and TSA are the best of the tested markers. These markers should prove useful for monitoring malignant disease stage and for evaluating the effectiveness of various therapeutic approaches for colorectal carcinomas.  相似文献   
83.
84.
JC virus (JCV) is a polyomavirus infecting greater than 80% of the human population early in life. Replication of this virus in oligodendrocytes and astrocytes results in the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) in immunocompromised individuals, most notably acquired immunodeficiency syndrome (AIDS) patients. Moreover, recent studies have pointed to the association of JCV with a variety of brain tumors, including medulloblastoma. The JCV genome encodes for viral early protein, including large and small T antigens and the newly discovered isoform T', at the early phase of infection and the structural proteins VP1, VP2, and VP3 at the late stage of the lytic cycle. In addition, the late gene is responsible for the production of a small nonstructural protein, agnoprotein, whose function is not fully understood. Here, we have summarized some aspects of the JCV genome structure and function, and its associated diseases, including PML and brain tumors.  相似文献   
85.
The present retrospective study aims to determine the clinical value of thymidine labelling index (TLI) together with other established clinical and biological factors in 116 locally advanced breast cancer (LABC) patients treated with anthracycline-based neoadjuvant chemotherapy, surgery, adjuvant chemotherapy and radiotherapy. TLI was determined in 71 LABC patients with a median of 2.62% (0–23.64%) and a mean of 4.71%±5.54. As a result of neoadjuvant chemotherapy, 85 patients (73%) responded to chemotherapy (CT), whereas 31 patients were unresponsive (27%). No relationship has been found between the pretreatment biological variables including TLI, estrogen receptor (ER), progesteron receptor (PgR) status and clinical parameters such as the chemotherapy response rates and axillary lymph node involvement following chemotherapy. Median follow-up was 35 months (18–97 months) and the 3-year overall survival (OS) and disease free survival (DFS) rates were 71.6% and 52.2%, respectively. In univariate analysis, patients with inflammatory breast cancer, high TLI-index (2.62%), lymph node (LN) positivity or >3 positive lymph nodes following neoadjuvant chemotherapy and without any response to neoadjuvant chemotherapy were found to have worse DFS and OS-rates and high local and systemic recurrence rates. In multivariate analysis, TLI was estimated as the most powerful independent factor affecting the OS in LABC patients among the other established clinical and biological parameters (p=0.02). These results suggest that TLI is an important independent indicator of clinical outcome in patients with LABC and these patients with high TLI levels require more effective treatment modalities.  相似文献   
86.
Spinal metastasis of occult lung carcinoma causing cauda equina syndrome.   总被引:1,自引:0,他引:1  
Cauda equina syndrome (CES) may be caused by tumor, herniated disc, trauma and spinal infections. However, CES due to occult lung cancer has not been reported in the literature. A 50-year-old man presented with a subacute CES caused by an intradural metastasis of an adenocarcinoma of the lung to the lumbosacral cauda fibers. His lumbosacral magnetic resonance imaging (MRI), showed a well-demarcated, intradural extramedullary mass lesion resembling a neurinoma at the L4/5 level. The patient underwent an L4-L5 laminectomy. The operative findings were also suggestive of neurinoma with involvement of three nerve roots, and a well-demarcated tumor without infiltration into the subarachnoid space. Although the findings of the operation were suggestive of neurinoma, final pathological diagnosis revealed metastatic carcinoma. Immunohistochemistry revealed clear cell adenocarcinoma metastasis. Chest X-ray and high resolution contrasted pulmonary computed tomography were normal. Positron emission tomography (PET) showed a lung mass, at the left apex. The patient was treated with chemotherapy and post-operative spinal radiotherapy was also performed. The CES resolved after the operation and the patient was followed up for 2 years with no recurrence. MRI of intradural cauda equina metastasis may be similar to that of intradural nerve sheath tumor. Surgery and postoperative radiotherapy may be effective for the treatment of CES due to lung carcinoma. Definitive diagnosis is by histopathological examination with immunohistochemistry. If the primary cancer cannot be detected by conventional radiological techniques, PET may be helpful.  相似文献   
87.
AIMS: Heart rate turbulence (HRT) and heart rate variability (HRV) have been shown to be independent and powerful predictors of mortality in a specific group of cardiac patients. However, the predictive values of HRV alone is modest and information on HRV in patients with mitral valve prolapse (MVP) has so far been conflicting. In addition, no studies have previously evaluated HRT in patients with MVP. To define better the effects of MVP on cardiac autonomic function, we assessed HRT and time-domain parameters of HRV in patients with MVP. METHODS AND RESULTS: Fifty patients with MVP and 70 controls without MVP were investigated. The diagnosis of MVP was confirmed by cross-sectional echocardiography in the parasternal long-axis view and apical 4-chamber view. The HRV and turbulence analysis were assessed from a 24-hour Holter recording. When HRT parameters were compared, the values of the HRT onset and slope were significantly lower in MVP patients than in the controls group (-0.109+/-0.207 vs. -0.289+/-0.170%, P=0.001 and 8.6+/-7.2 vs. 11.5+/-7.4 ms/RRI, P=0.043, respectively) and the number of patients who had abnormal HRT onset was significantly higher in the MVP group than in controls (15 vs. 8, P=0.011). In addition, HRV parameters were not statistically different between the two groups. CONCLUSION: Although we found that the decrease in HRV parameters was not significantly different between MVP patients and controls, HRT variables (especially HRT onset) were significantly lower in MVP patients. Therefore, in our opinion, HRT is an attractive, easily applicable, and better way of non-invasive risk prediction compared with another non-invasive risk predictor, HRV.  相似文献   
88.
Antidepressants are drugs used for the treatment of many psychiatric conditions including depression. There are findings suggesting that these drugs might have genotoxic, carcinogenic, and/or mutagenic effects. Therefore, the present in vitro study is intended to investigate potential genotoxic and cytotoxic effects of the antidepressants escitalopram (selective serotonin reuptake inhibitor) and doxepin (Tricyclic antidepressant) on human peripheral lymphocytes cytokinesis-block micronucleus (CBMN), sister chromatid exchange (SCE), and single cell gel electrophoresis (alkaline comet assay) were used for the purpose of the study. In the study, four different concentrations of both drugs (1, 2.5, 5, and 10?µg/mL) were administered to human peripheral lymphocytes for 24?h. The tested concentrations of both drugs were found to exhibit no cytotoxic and mitotic inhibitory effects. SCE increase caused by 5 and 10?µg/mL of escitalopram was found statistically significant, while no statistically significant increase was observed in DNA damage and micronucleus (MN) formation. Moreover, the increase caused by doxepin in MN formation was not found statistically significant. Besides, 10?µg/mL of doxepin was demonstrated to significantly increase arbitrary unit and SCE formation. These findings suggest that the investigated concentrations of escitalopram and doxepin were non-cytotoxic but potentially genotoxic at higher concentrations.  相似文献   
89.
Purpose This study was designed to review the outcomes of emergent treatment of sigmoid colon volvulus. Methods The records of 827 patients were reviewed retrospectively. Results The mean age was 57.9 years (range, 10 weeks to 98 years), and 688 patients (83.2 percent) were male. Nonoperative reduction was applied in 575 patients (barium enema in 13, rigid sigmoidoscopy in 351, and flexible sigmoidoscopy in 211, with rectal tube placement in all patients). The results were as follows: success of 78.1 percent, mortality of 0.9 percent, complication of 3 percent, and early recurrence of 3.3 percent. Surgical treatment was performed on 393 patients (detorsion in 46, mesosigmoidopexy in 56, exteriorization in 4, resection with Hartmann’s procedure in 146, resection with Mikulicz procedure in 14, resection with primary anastomosis in 51, tube cecostomy and colonic cleansing with resection in 75, and laparotomy in 1). The results were as follows: mortality of 15.8 percent, complication of 37.2 percent, early recurrence of 0.8 percent, and late recurrence of 6.7 percent. Conclusions Nonoperative reduction is the initial treatment of sigmoid colon volvulus, and flexible sigmoidoscopy with rectal tube placement can be used successfully. Patients in whom bowel gangrene or peritonitis is present or nonoperative treatment is unsuccessful need emergency surgery. In surgical treatment, resection and primary anastomosis is the first choice, and it can be performed with acceptable mortality and morbidity rates if the patient is stable and a tension-free anastomosis is possible. Nondefinitive procedures have high recurrence rates; thus, definitive surgical techniques must be preferred.  相似文献   
90.
Thymic hyperplasia is a common phenomenon in both children and young adults after chemotherapy and may explain the finding of a mediastinal mass in patients with malignant lymphoma after complete remission. In the present study, we report 5 cases with malignant lymphoma presenting with a mediastinal mass on CT scan after completion of chemotherapy diagnosed as thymic hyperplasia by PET-CT imaging. We retrospectively analyzed 5 patients who presented with anterior mediastinal masses a median of 4 months (range 3–6) after achieving complete remission following successful treatment for malignant lymphoma. Three patients were diagnosed with Hodgkin’s lymphoma (HL) and the others with non-Hodgkin’s lymphoma (NHL). The median age of the patients was 23 (range of 18–47). PET-CT was performed on these patients to determine the characteristics of a mass which had been detected on CT. PET-CT was performed for all patients, and the thymic masses demonstrated only mild FDG uptake considered to be consistent with thymic hyperplasia. During a median of 24 months of follow-up, all patients were recurrence-free with a median survival of 15 months (range 10–26 months). It is important to be aware of the possibility of thymic hyperplasia after chemotherapy to avoid misdiagnosis or over-staging of disease, as well as unnecessary biopsies, especially when the presenting anterior mediastinal mass was originally located near the thymus on CT scan. Mild FDG PET uptake was sufficient for the diagnosis of benign disease in the cases in this study.  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