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   1149篇
  免费   34篇
  国内免费   1篇
耳鼻咽喉   14篇
儿科学   93篇
妇产科学   50篇
基础医学   85篇
口腔科学   56篇
临床医学   92篇
内科学   225篇
皮肤病学   23篇
神经病学   47篇
特种医学   33篇
外科学   209篇
综合类   10篇
预防医学   23篇
眼科学   16篇
药学   23篇
中国医学   6篇
肿瘤学   179篇
  2024年   2篇
  2023年   10篇
  2022年   15篇
  2021年   33篇
  2020年   39篇
  2019年   38篇
  2018年   36篇
  2017年   24篇
  2016年   35篇
  2015年   38篇
  2014年   40篇
  2013年   58篇
  2012年   92篇
  2011年   76篇
  2010年   52篇
  2009年   60篇
  2008年   87篇
  2007年   93篇
  2006年   85篇
  2005年   70篇
  2004年   79篇
  2003年   55篇
  2002年   45篇
  2001年   3篇
  2000年   4篇
  1999年   2篇
  1997年   4篇
  1995年   1篇
  1994年   1篇
  1992年   4篇
  1991年   2篇
  1990年   1篇
排序方式: 共有1184条查询结果,搜索用时 15 毫秒
71.
BACKGROUND: The risk of ipsilateral breast tumor recurrence (IBTR) after breast-conserving therapy (BCT) is associated with treatment and tumor-related variables, such as surgical margin status and the use of systemic therapy, and these variables have changed over time. Correspondingly, the authors of the current study hypothesized that the contemporary multidisciplinary management of breast carcinoma would lead to an improvement in IBTR rates after BCT. METHODS: Between 1970 and 1996, 1355 patients with pathologic Stage I-II invasive breast carcinoma underwent BCT (breast-conserving surgery and adjuvant radiation therapy) at The University of Texas M. D. Anderson Cancer Center. Contemporary methods of analyzing surgical margins were in routine use by 1994. To analyze the effect of this variable and others, patient and tumor characteristics and IBTR rates in patients treated during 1994-1996 were compared with those in patients treated from 1970 to 1993. RESULTS: Characteristics were similar in patients treated during 1994-1996 (n = 381) and those treated before 1994 (n = 974) except for patients aged >50 years (63.3% vs. 51.7%, P < 0.001), and patients who had a family history of breast carcinoma (37.9% vs. 30.8%, P = 0.017). Patients treated after 1994 were less likely to have positive or unknown margins (2.9 % vs. 24.1 %, P = 0.0001), more likely to receive chemotherapy (40.5% vs. 26%, P < 0.001), and more likely to receive hormonal therapy (33.3% vs. 19.4%, P < 0.001), but less likely to receive radiation boosts to the primary tumor bed (59.8% vs. 89%, P < 0.001). The 5-year cumulative IBTR rate was significantly lower among patients treated in 1994-1996 than among patients treated before 1994 (1.3% vs. 5.7%, P = 0.001) largely because of the drop in IBTR rates among patients aged < or = 50 years (1.4 % vs. 9.1 %, P = 0.0001). On multivariate analysis, age > 50 (hazards ratio [HR] = 0.401; P = 0.0001), presence of negative surgical margins (HR = 0.574; P = 0.017), and use of adjuvant hormonal therapy (HR = 0.402; P = 0.05) were independent predictors of improved 5-year IBTR-free survival. On subgroup analysis, use of chemotherapy was associated with increased IBTR-free survival among women aged < or = 50 years (HR = 0.383; P = 0.001). Although 5-year cumulative IBTR rates were lower among women aged > 50 years than among younger women before 1994 (2.6 % vs. 9.1%, P < 0.0001), no such difference was found in the group treated in 1994-1996 (1.2 % for age > 50 yrs vs. 1.4 % for < or = 50 yrs, P = 0.999). CONCLUSIONS: The IBTR rate after BCT appears to be declining, especially among patients < 50 years of age. However, long-term follow-up is necessary to confirm this finding. This finding may reflect changes in surgical approaches and pathologic evaluation as well as an increased use of systemic therapy. The current low incidence of IBTR with multidisciplinary management of breast carcinoma may result in more patients choosing BCT over mastectomy.  相似文献   
72.
BACKGROUND AND OBJECTIVE: The aim of our study was to investigate, in rabbits with hydrochloric (HCl) acid-induced Acute Lung Injury (ALI), the effects of intra-tracheal (i.t.) dexamethasone administration on neutrophil and platelet counts, plasma malonyl dialdehyde (MDA) level, histopathology, and arterial blood gases. METHODS: Twenty-eight New Zealand rabbits were randomly divided into a control (n = 14) and dexamethasone groups (n = 14). Anesthesia was applied with ketamine (50 mg kg(-1) h(-1), i.m.) and tracheostomy was performed. Both groups received 2 ml kg(-1) HCl (hydrochloric acid) i.t.. Five minutes later, 0.9% saline was given to the controls while the other group received i.t. dexamethasone. MDA levels of the plasma, neutrophil and platelet counts, and arterial blood gases were recorded at the beginning of the study and then at two and five hours. The rabbits were ventilated in pressure control mode for 5 hours. At the end of the study, the lungs were examined by light microscopy and the changes evaluated on a scale of 0 to 4. RESULTS: Neutrophil and platelets counts (p < 0.01) and PaO2 (p < 0.05) were greater in the dexamethasone group than the controls at five hours. Plasma MDA level (p < 0.01) and PaCO2 (p < 0.01) were greater in the control group. Histopathological changes were less severe in the dexamethasone group. CONCLUSION: Giving dexamethasone i.t. may have beneficial effects on the development of ALI.  相似文献   
73.
Cryptogenic cirrhosis (CC) is diagnosed in 5-30% of cirrhotic patients overall and 7% of patients who undergo liver transplantation for cirrhosis. In our series of patients transplanted for CC, pre-transplant clinical and histological data and the post-transplant course were reexamined in an attempt to identify the aetiology. Among the 881 patients transplanted in our centre between 1987 and 2000, 28 patients with a median age of 46 yr (range: 18-69) at transplantation were initially classified as having CC. Two patients were excluded because of intense ischaemic lesions caused by chemoembolization prevented histological analysis of the native liver (n = 1) and because of cryptic HBV infection (n = 1). Among the remaining 26 patients, four groups were individualized: (i) patients with chronic inflammatory liver disease with autoimmune features (n = 14, 54%); (ii) patients with features suggestive of non-alcoholic fatty liver disease (n = 3, 11.5%); (iii); patients with incomplete septal cirrhosis (ISC) and vascular liver disease (n = 3), and (iv) patients with unresolved CC (n = 6, 23%). In the autoimmune liver disease group, the median International Autoimmune Hepatitis score was 12.5 (range: 11-19) after reevaluation and review of the post-transplantation course was helpful to confirm the diagnosis with the occurrence of active graft hepatitis in nine patients, with autoantibodies in five patients. The vascular group was characterized by lesions of obliterative portal venopathy and ISC in all native livers. Diagnosis of NAFLD was based on the clinical background of obesity and/or type 2 diabetes and the presence of steatosis or steatohepatitis in native livers and graft biopsies. A definite aetiological diagnosis can be achieved in the majority of patients initially diagnosed with CC. Autoimmune liver disease emerged as the main aetiology (14 of 26 patients, 54%) and frequently recurred on the grafted liver (nine cases). In all cases a precise diagnosis is obviously of practical interest for better management of post-transplant survey and treatment.  相似文献   
74.
An inflammatory myofibroblastic tumor is an uncommon benign tumor located in various organs that can be misdiagnosed as a malignant neoplasm. We herein present two patients with ileocecal inflammatory myofibroblastic tumors. An abdominal mass was detected in a 13-year-old girl and a 15-year-old boy who presented with paleness, fatigue, intermittent fever, and night sweating. The radiological findings confirmed a mass originating from the ileocecal region. The presumptive diagnosis was Burkitt’s lymphoma. The histopathological diagnosis was inflammatory myofibroblastic tumor. After a surgical resection, all systemic symptoms rapidly resolved. Inflammatory myofibroblastic tumor is a rare pseudosarcomatous clinical and pathological entity. Although this tumor is more commonly reported in the lung, it can be detected in extrapulmonary sites, including the mesentery. Because the choice of treatment for this tumor is conservative surgery, an accurate preoperative analysis is important to avoid any unnecessary aggressive surgical intervention or other therapeutic approaches.  相似文献   
75.
OBJECTIVE: Invasive lobular carcinoma (ILC) presents special challenges to treating physicians because of the diffuse infiltrative growth pattern. As sentinel lymph node dissection (SLND) is rapidly replacing axillary lymph node dissection (ALND) in the management of patients with early-stage breast cancer, we sought to evaluate the safety of SLND in providing axillary control in breast cancer patients with lobular histology and a negative sentinel node. METHODS: We identified 239 patients with T1-2,N0,M0 lobular breast cancer from the prospective databases of 2 institutions; all were treated between March 1994 and December 2003. RESULTS: A total of 202 patients had SLND and 37 had SLND followed by ALND. There was no significant difference between the 2 groups with respect to tumor size, presence of lymphovascular invasion, estrogen receptor (ER)/progesterone receptor (PR) and HER-2/neu status, type of breast surgery, margin status, or nuclear grade. Use of chemotherapy, radiation, and hormonal therapy was not significantly different between groups. At a median follow-up of 48 months in the ALND group and 26 months in the SLND group (range 6 to 80 months), none of the 202 patients in the SLND group had experienced an axillary recurrence, while 2 (5.4%) of the 37 patients who underwent ALND had experienced an axillary recurrence. CONCLUSIONS: SLND provided axillary control equivalent to that of ALND for patients with lobular breast cancer. SLND alone appears to be adequate axillary management of patients with lobular breast cancer and a negative sentinel node.  相似文献   
76.
BACKGROUND AND PURPOSE: Earlier studies have shown an association between mood disorders and sleep regulation. Total or partial sleep deprivation was demonstrated to have rapid antidepressive effects in depression. Depressive symptoms recur after one night of recovery sleep, but relapse is less when patients are receiving medication. In this study, we examined the subjective sleep quality changes with the antidepressive therapy using partial sleep deprivation plus sertraline and sertraline monotherapy in patients with major depressive disorder. PATIENTS AND METHODS: Thirteen patients received six partial sleep deprivation therapies in addition to sertraline; the sleep schedule on deprivation nights started at 11:00 p.m. and ended at 3:00 a.m. Eleven patients were treated with sertraline monotherapy as a control group. Six nights of partial sleep deprivation were completed in the first two weeks. Subjective sleep quality was evaluated with the Pittsburgh Sleep Quality Index (PSQI); depression and the accompanying anxiety were also assessed at baseline and at the end of the fourth week. RESULTS: The late partial sleep deprivation (LPSD) group showed less increase in estimated sleep duration and less significant improvement in subjective sleep quality than the control group. Although decreased sleep latency and increased sleep efficiency are associated with the sleep deprivation, contrary results were found in our study. CONCLUSIONS: In conclusion, changes in subjective sleep quality could occur relative to the combined partial sleep deprivation therapy and to pharmacotherapy and must be differentiated from the rapid effects of sleep deprivation therapy and objective polysomnographic measures.  相似文献   
77.
In this study, 136 febrile neutropenic episodes were overviewed retrospectively. Factors affecting treatment success and cost were analyzed. Twenty percent of the episodes were microbiologically documented and 51% of the bacterial isolates were gram negatives. The most commonly used empirical therapies in febrile episodes were the combination of two drugs (58.0%), monotherapy (14.8%), and antibiotics plus fluconazole (20.6%). In lymphoproliferative tumors duration of fever and discharge from the hospital were longer. Administration of the hematopoietic growth factors shortened neither the duration of neutropenia nor fever and hospitalization. Treatment costs were higher in lymphoproliferative tumors, in bacteremia, and in episodes where glycopeptides, antifungal drugs, and hematopoietic growth factors were used. In conclusion, duration of neutropenia was a significant independent predictive factor for duration of fever. In the lymphoproliferative tumors, duration of fever was longer and cost of treatment was more than in the solid tumors.  相似文献   
78.
Expression of c-kit proto-oncogene product in breast tissue   总被引:3,自引:0,他引:3  
The proto-oncogene c-kit encodes a transmembrane tyrosine kinase growth factor receptor. Stem cell factor, the receptor ligand, plays an important role in the development of certain neoplasms. c-kit is selectively and competitively bound by STI-571, a newly developed tyrosine kinase inhibitor. Several investigators report conflicting results concerning its expression, especially in malignant breast lesions. The objective of this study was to better characterize the expression of c-kit within the spectrum of breast epithelium (normal breast epithelium, nonneoplastic lesions, and breast carcinoma). Seventy-seven randomly selected breast tissue samples, each containing normal breast epithelium (21), invasive breast carcinoma (41), in situ breast carcinoma (29), papilloma (8), fibroadenoma (5), fibrocystic change (11), and/or metastatic breast carcinoma (4), were immunostained with polyclonal rabbit antihuman c-kit (Dako, Carpenteria, CA) at a dilution of 1:200. The staining was interpreted as negative if no cells were immunoreactive, weak positive if 5% of the cells were immunoreactive, and positive if more than 5% of the cells were immunoreactive. Appropriate positive and negative controls were used. The observed staining was cytoplasmic, with highlighting of the nuclear membrane. Normal breast epithelium was positive in all cases. More than half of the cases of hyperplastic changes and benign neoplasms (fibroadenoma and papilloma) were positive. Only 10% of invasive and in situ carcinomas showed positivity for c-kit. c-kit is consistently expressed in normal breast epithelium, variably expressed in benign breast lesions, and poorly expressed in breast carcinoma. These data suggest that c-kit may play a role in breast tumor progression and may therefore have diagnostic, prognostic, and therapeutic implications.  相似文献   
79.
BACKGROUND: Patients with chronic renal failure (CRF) are restricted in physical, emotional and social dimensions of life due to their treatment and their comorbid medical conditions. We aimed to evaluate the effects of a 12-week exercise program on the functional capacity, functional mobility, walking capacity, quality of life and depression in patients with renal failure on hemodialysis (HD). METHODS: Twenty patients with renal failure on HD were included and 14 of them completed the study. The patients went through a 12-week exercise program of 90 min/day, 3 days a week. Exercise and walking capacity, functional mobility, psychological status and quality of life were evaluated pre- and post-training. RESULTS: Following the exercise, peak oxygen consumption, exercise duration and peak workload improved significantly (respectively, p=0.006, p=0.002 and p=0.002). There were significant improvements in the sit-to-stand-to-sit test and the 6- min walk test (p<0.001 and p=0.002). There was a significant reduction in the depression score (p<0.001). Both physical component scale (PCS) and mental component scale (MCS) of the Kidney Disease Quality of Life Short-Form 36 (SF-36) questionnaire showed significant increases (respectively, p=0.002 and p=0.004). CONCLUSION: The application of an appropriate exercise program would improve psychological status and quality of life, as well as work capacity in long-term maintenance HD patients.  相似文献   
80.
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