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   2513篇
  免费   87篇
  国内免费   11篇
耳鼻咽喉   107篇
儿科学   163篇
妇产科学   121篇
基础医学   210篇
口腔科学   102篇
临床医学   219篇
内科学   488篇
皮肤病学   48篇
神经病学   124篇
特种医学   86篇
外科学   550篇
综合类   27篇
预防医学   61篇
眼科学   37篇
药学   83篇
中国医学   1篇
肿瘤学   184篇
  2024年   1篇
  2023年   18篇
  2022年   28篇
  2021年   50篇
  2020年   32篇
  2019年   55篇
  2018年   62篇
  2017年   60篇
  2016年   77篇
  2015年   87篇
  2014年   100篇
  2013年   153篇
  2012年   210篇
  2011年   192篇
  2010年   117篇
  2009年   88篇
  2008年   175篇
  2007年   207篇
  2006年   177篇
  2005年   198篇
  2004年   162篇
  2003年   116篇
  2002年   95篇
  2001年   29篇
  2000年   35篇
  1999年   25篇
  1998年   10篇
  1997年   9篇
  1996年   10篇
  1995年   2篇
  1994年   6篇
  1993年   5篇
  1992年   4篇
  1991年   6篇
  1990年   3篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1969年   1篇
  1961年   1篇
排序方式: 共有2611条查询结果,搜索用时 15 毫秒
11.
The aim of this prospective study was to determine the diagnostic value of Tc-99m MDP scintimammography (SMG) for the detection of breast cancer in patients with breast masses and to compare the results with Tc-99m MIBI scintimammography. Twenty patients, categorized as suspicious, positive or benign for breast cancer according to the mammographic findings were included in the study. Dual phase Tc-99m MIBI and Tc-99m MDP SMG were performed in the prone lateral position within 5 days of each other. Although early and late Tc-99m MIBI SMG showed equal (90.4%) sensitivity, the specificity of late Tc-99m MIBI (87.5%) was found superior to early (62.5%) imaging. The overall sensitivity and specificity of early Tc-99m MDP SMG were 71.4% and 62.5%, respectively. Although late Tc-99m MDP imaging showed 100% specificity, its sensitivity was only 23.8%. In the patients with palpable masses, both early Tc-99m MDP and Tc-99m MIBI showed equal sensitivity (100%), but the sensitivity of early Tc-99m MIBI (37.5%) was found slightly higher than Tc-99m MDP (25.0%) for nonpalpable breast lesions. The sensitivity of Tc-99m MIBI and Tc-99m MDP SMG in detecting metastatic axillary involvement was 66.6% and 50%, respectively. High sensitivity and specificity together with its low cost, easy availability and the possibility of detecting bone metastases seems to make Tc-99m MDP a contributive agent in the evaluation of breast lesions as an alternative to Tc-99m MIBI.  相似文献   
12.
In hypersensitive reactions to native L‐asparaginase, either premedication and desensitization or substitution with polyethylene glycol conjugated asparaginase (PEG‐ASP) is preferred. Anaphylaxis with PEG‐ASP is rare. An 8‐year‐old girl and a 2.5‐year‐old boy, both diagnosed as having acute lymphoblastic leukemia, presented with native L‐asparaginase hypersensitivity and substitution with PEG‐ASP was preferred. They received a premedication (methylprednisolone, hydroxyzine and ranitidine) followed by desensitization with PEG‐ASP infusion. Both patients developed anaphylaxis with peg‐asparaginase. These are the first reported cases of anaphylactic reaction to PEG‐ASP, despite the application of both premedication and desensitization. Anaphylaxis with PEG‐ASP is very rare and premedication and desensitization protocols may not prevent these hypersensitive reactions.  相似文献   
13.

Background

Spinal myxopapillary ependymomas (MPEs) are slowly growing ependymal gliomas with preferential manifestation in young adults. The aim of this study was to assess the outcome of patients with MPE treated with surgery, radiotherapy (RT), and/or chemotherapy.

Methods

The medical records of 183 MPE patients (male: 59%) treated at the MD Anderson Cancer Center and 11 institutions from the Rare Cancer Network were retrospectively reviewed. Mean patient'' age at diagnosis was 35.5 ± 15.8 years. Ninety-seven (53.0%) patients underwent surgery without RT, and 86 (47.0%) were treated with surgery and/or RT. Median RT dose was 50.4 Gy. Median follow-up was 83.9 months.

Results

Fifteen (8.2%) patients died, 7 of unrelated cause. The estimated 10-year overall survival was 92.4% (95% CI: 87.7–97.1). Treatment failure was observed in 58 (31.7%) patients. Local failure, distant spinal relapse, and brain failure were observed in 49 (26.8%), 17 (9.3%), and 11 (6.0%) patients, respectively. The estimated 10-year progression-free survival was 61.2% (95% CI: 52.8–69.6). Age (<36 vs ≥36 y), treatment modality (surgery alone vs surgery and RT), and extent of surgery were prognostic factors for local control and progression-free survival on univariate and multivariate analysis.

Conclusions

In this series, treatment failure of MPE occurred in approximately one third of patients. The observed recurrence pattern of primary spinal MPE was mainly local, but a substantial number of patients failed nonlocally. Younger patients and those not treated initially with adjuvant RT or not undergoing gross total resection were significantly more likely to present with tumor recurrence/progression.  相似文献   
14.
The aim of this study was to examine prenatal diagnosis of double-outlet right ventricle (DORV)-associated anomalies and prognosis of each case. Medical records were reviewed of fetuses with DORV who had fetal echocardiography at our institution from 2002 to 2006. Pre- and postnatal diagnosis and outcome were compared and evaluated. Twenty-one fetuses were diagnosed with DORV. The pregnancy was terminated in seven cases. Three cases had chromosomal abnormalities; three cases, hypoplastic left ventricle; and one case, encephalocele. Accurate prenatal diagnosis of the ventricular septal defect, outflow obstruction, and great artery relationship was achieved in 14 of 16 cases (87.5%). Only 2 of 13 live-born cases survived beyond 6 months. The overall prognosis for fetuses with DORV is poor. DORV is found in fetuses with a huge spectrum of associated cardiac and extracardiac anomalies. Careful assessment by fetal echocardiography can determine important anatomic details with adequate correctness for precise counseling.  相似文献   
15.
16.
BACKGROUND: The molecular mechanisms in malignant transformation of laryngeal mucosa are unknown; many clinical and pathological factors affect prognosis. We investigated a possible correlation between overexpression of p53, proliferating cell nuclear antigen (PCNA), and c-erbB-2, and the clinicopathologic features of laryngeal squamous cell carcinoma (SCC) and clarify their prognostic value. MATERIAL/METHODS: Thirty-three men with laryngeal SCC participated; all underwent primary surgery or surgery plus radiotherapy between 1999 and 2004 at our department. Paraffin sections of laryngeal SCC were immunohistochemically stained for p53, PCNA, and c-erbB-2. RESULTS: Overall, p53 overexpression was found in 16 patients. There was no relation between p53 immunohistochemical staining and tumor region. PCNA immunostaining was significantly stronger in supraglottic tumors compared with glottic tumors. Immunostaining of c-erbB-2 was not different in either location. There was no relation between the T stage of the tumor and p53 and c-erbB-2 immunostaining. However, there was a statistically significant positive correlation between the PCNA staining and T stage (stronger staining was present in T3 and T4 stages than in T1 and T2 stages). CONCLUSIONS: We could not find a statistically significant correlation between p53, PCNA, and c-erbB-2 and lymph node status, histologic differentiation, and survival rate. We demonstrated only a statistically significant positive correlation between PCNA staining and T stage. These data suggest that overexpression of p53, PCNA, and c-erbB-2 is not prognostic in laryngeal SCC.  相似文献   
17.
BackgroundInflammatory bowel diseases (IBDs), Crohn's disease, and ulcerative colitis are considered to be chronic inflammatory disorders implicated with recurrent tissue damage to the intestine. There is a positive correlation between platelet–leukocyte aggregates and ischemic vascular risk. There are limited data about the relationship between platelet–leukocyte aggregates and IBD. This study was designed to determine whether platelet–leukocyte aggregates increase in IBD, and whether a relationship exists between the elevation of platelet–leukocyte aggregates and disease activity.MethodsA total of 20 patients with IBD (16 with ulcerative colitis and 4 with Crohn's disease) and 20 healthy controls participated in our study. Nine patients were in active-phase IBD, whereas 11 patients were in inactive phase. To show the presence of thrombocyte aggregates, the monoclonal antibodies such as Isotype IgG1 mouse antihuman CD42b-PE (phycoerythrin) (Beckman Coulter IMI417), Isotype IgG1 mouse antihuman CD45-FITC (fluorescein isothiocyanate) (Beckman Coulter IM0782), and Isotype IgG2a mouse antihuman CD45RO-FITC (Beckman Coulter IMI247) were used. Additionally, the values of platelet–neutrophil aggregates were measured in peripheral blood samples using flow cytometry techniques.ResultsThe levels of platelet–leukocyte aggregates in blood samples were found to be significantly higher during both the active and inactive phases in patients with IBD. There were no statistically significant differences between active-phase and inactive-phase patients.ConclusionWe determined that the patient group had significantly higher platelet–leukocyte aggregate levels compared with the control group. This finding suggests that platelet–leukocyte aggregates may play a role in the development of IBD.  相似文献   
18.
The mineral content of 43 honey samples from the middle regions of Turkey was investigated. Minerals were determined by inductively coupled plasma-atomic emission spectrophotometer. Calcium, potassium, sodium and phosphorus were the most abundant of the elements in all the studied honeys, with average concentrations ranging between 40.13 and 189.69 mg/kg for calcium, 161.01 and 598.62 mg/kg for potassium, 9.34 and 45.9 mg/kg for sodium, and 460.11 and 3,776.96 mg/kg for phosphorus. Cluster analysis of the honey data revealed that the mineral content of Çorum and Konya honeys was closer as they formed a cluster at a similarity level of 60%.  相似文献   
19.
20.
Thalidomide is shown to be an effective treatment for mucocutaneous symptoms of Behcet's disease (BD). In this study, the effects of thalidomide on peripheral blood mononuclear cells were investigated ex vivo. In an open prospective study, ten patients were given 200 mg/day thalidomide for 12 weeks and cluster of differentiation 4 (CD4), CD8, CD11a, CD11b, CD16, CD18, CD28, CD44, CD45RO, CD45RA, CD56, CD120a and γδ+ T cells were analysed with flow cytometry at 0, 3, 7, 30 and 90 days. Two patients were excluded from the analysis for attacks of uveitis within the first 2 weeks. At day 7, tumour necrosis factor-α (TNF-α) receptor+ (CD120a; 12% vs 5%), CD8/CD11b+ (12% vs 6%) and CD16/CD56+ (16% vs 9%) cells decreased in BD patients compared to day 0. On the other hand, CD4+CD45RO+ T cells (24% vs 34%) at day 30 and γδ+ T cells (11% vs 21%) at day 90 increased after treatment. These results suggest that thalidomide tends to decrease TNF-α receptor levels, CD8/CD11b+ T cells and natural killer cells in early treatment and increases CD4+CD45RO+ memory T and γδ+ T cells later in BD.  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