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   702篇
  免费   22篇
  国内免费   7篇
耳鼻咽喉   9篇
儿科学   38篇
妇产科学   43篇
基础医学   69篇
口腔科学   7篇
临床医学   61篇
内科学   190篇
皮肤病学   12篇
神经病学   53篇
特种医学   9篇
外科学   75篇
综合类   5篇
预防医学   30篇
眼科学   22篇
药学   58篇
肿瘤学   50篇
  2024年   1篇
  2023年   8篇
  2022年   5篇
  2021年   16篇
  2020年   18篇
  2019年   10篇
  2018年   15篇
  2017年   17篇
  2016年   16篇
  2015年   31篇
  2014年   29篇
  2013年   31篇
  2012年   45篇
  2011年   64篇
  2010年   32篇
  2009年   28篇
  2008年   66篇
  2007年   68篇
  2006年   63篇
  2005年   49篇
  2004年   56篇
  2003年   25篇
  2002年   22篇
  2001年   5篇
  2000年   3篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
排序方式: 共有731条查询结果,搜索用时 78 毫秒
61.
Colitis cystica profunda (CCP) is an uncommon benign condition characterized by mucin-filled cysts located in the submucosa, frequently associated with the solitary ulcer and rectal prolapse syndromes. The diagnosis of this entity is important as it can mimic rectal cancer and therefore may result in unnecessary surgical resection. Endoscopic examination and barium enema findings are suggestive but not specific, neither are superficial biopsy findings. Transrectal ultrasound is helpful in the diagnosis by imaging the layers of the rectal wall. The authors report a 16-year-old male with a rectal lesion mimicking malignant mass on endoscopic examination. The lesion was defined as CCP, based on MR imaging findings which disclosed multiple noninfiltrating submucosal cysts, confirmed by histopathological examination. To our knowledge, this is the first case of CCP in the radiology literature describing MRI findings.  相似文献   
62.
Although moderate alcohol consumption seems to be protective against atherosclerosis, coronary artery disease rate increases with its higher doses. Platelet aggregation is an important process which contributes to the atherosclerosis. The aim of this study was to determine whether heavy ethanol consumption stimulates or inhibits platelet aggregation. Fourteen adult male Wistar rats were used. Ethanol (7.2%, v/v) in a modified liquid diet was given to eight rats for 21 days, which mimicked characteristics similar to human chronic alcoholism. Six rats constituted the control group. Adenosine diphophate (ADP) and collagen-induced platelet aggregation was measured in whole blood. We found reduced ADP-induced mean maximal aggregation in the alcoholic rat group compared to the control group at dose of 5 microM (p < 0.005). We also found decreased platelet aggregation responses to collagen in the alcoholic group (p < 0.006 for 2 microg/ml collagen, and p < 0.05 for 5 microg/ml collagen). In conclusion, chronic heavy ethanol consumption results in the decreased platelet aggregation in a rat model of alcoholism. Therefore, increased mortality from coronary artery disease in chronic alcoholism may be explained by other factors such as dietary imbalances and coexisting conditions, which include hypertension and depression.  相似文献   
63.
In this article, we aimed to reduce the effects of geometric errors and measurement noise on the inverse problem of Electrocardiography (ECG) solutions. We used the Kalman filter to solve the inverse problem in terms of epicardial potential distributions. The geometric errors were introduced into the problem via wrong determination of the size and location of the heart in simulations. An error model, which is called the enhanced error model (EEM), was modified to be used in inverse problem of ECG to compensate for the geometric errors. In this model, the geometric errors are modeled as additive Gaussian noise and their noise variance is added to the measurement noise variance. The Kalman filter method includes a process noise component, whose variance should also be estimated along with the measurement noise. To estimate these two noise variances, two different algorithms were used: (1) an algorithm based on residuals, (2) expectation maximization algorithm. The results showed that it is important to use the correct noise variances to obtain accurate results. The geometric errors, if ignored in the inverse solution procedure, yielded incorrect epicardial potential distributions. However, even with a noise model as simple as the EEM, the solutions could be significantly improved.  相似文献   
64.
Recent studies have indicated that bone marrow stromal cells (BMSCs) have significant tropism towards glioma which makes them play an important role in carrying genes/drugs to inhibit the growth of glioma as cell vehicles. But BMSCs may differentiate into neural cells under entocranial environment and few researches support the idea that neurally differentiated bone marrow stromal cells (N-D-BMSCs) still hold the capacity of migrating to the tumor sites. The aim of our study was to investigate the tropism of N-D-BMSCs towards C6 glioma. In vitro migration assay was employed by transwell co-culture system and Student's t-test analysis indicated that N-D-BMSCs had the significant tropism towards C6 glioma-conditioned medium (GCM) (P < 0.01). Furthermore, the vascular endothelial growth factor (VEGF) bioactivity of the C6 GCM was neutralized by the anti-rat VEGF antibody and our data suggested that the VEGF from C6 GCM hold chemoattraction for N-D-BMSCs and some other cytokines from the C6 GCM may be responsible for the chemoattraction for N-D-BMSCs. In vivo migration assay was carried out with cells transplantation and one way ANOVA analysis indicated that the tropism of N-D-BMSCs towards C6 glioma sites presented time variation (P-value = 2.9E−20). Moreover, multiple comparisons for the time variables with the Student's t-test and the results suggested that the migration capacity of N-D-BMSCs towards C6 glioma sites reach the peak on the 7th day after transplantation. These results demonstrate that N-D-BMSCs as well as BMSCs have significant tropism towards C6 glioma.  相似文献   
65.
66.
PURPOSE OF REVIEW: The purpose of this review is to help neurologists understand new concepts in hereditary neuropathies, from the clinician's point of view, in the molecular era after the burst of information regarding peripheral nerve biology. RECENT FINDINGS: Recent studies have focused on understanding the pathomechanisms involved in hereditary neuropathies. In the past year identification of new genes has slowed down since scientists have concentrated more on the function of genes causing Charcot-Marie-Tooth disease and Schwann cell-axon interactions to reveal the molecular cell biology of the disease. Animal models for the most common subtypes of human Charcot-Marie-Tooth disease are now available. SUMMARY: Rapid advances in the molecular genetics and cell biology of hereditary neuropathies have highlighted the great genetic complexity of Charcot-Marie-Tooth disease. The evolution from a simple clinical classification to a complex molecular one has not facilitated our understanding of the disease. Moreover, the new molecular classification is not simple to use as different mutations of the same gene produce a range of phenotypes. The clinicians have to look for specific clinical and electrophysiological clues to direct the patient to appropriate genetic testing.  相似文献   
67.
68.

Objective

The aim of this study was to investigate bone protective effects of risedronate, atorvastatin, raloxifene and clomiphene citrate in ovariectomized rats.

Methods

Our study was conducted on 63 rats at Experimental Research Center of Celal Bayar University. Six-month-old rats were divided into seven groups. There were five drug administered ovariectomized groups, one ovariectomized control group without drug administration and one non-ovariectomized control group without drug administration. Eight weeks postovariectomy, rats were treated with the bisphosphonate risedronate sodium, the statin atorvastatin, the estrogen 17β-estradiol and the selective estrogen receptor modulators (SERMs) raloxifene hydrochloride and clomiphene citrate by gavage daily for 8 weeks. At the end of the study, rats were killed under anesthesia. For densitometric evaluation, left femurs and tibiae were removed. Left femurs were also used to measure bone volume. Right femurs were used for three-point bending test.

Results

Compared to ovariectomized group, femur cortex volume increased significantly in non-ovariectomized group (p = 0.016). Compared to non-ovariectomized group, distal femoral metaphyseal and femur midshaft bone mineral density values were significantly lower in ovariectomized group (p = 0.047). In ovariectomy + atorvastatin group, whole femur and femur midshaft bone mineral density and three-point bending test maximal load values were significantly higher than ovariectomized group (p = 0.049, 0.05, and 0.018). When compared to the ovariectomized group, no significant difference was found with respect to femoral maximum load values in groups treated with risedronate, estrogen, raloxifene and clomiphene (p = 0.602, 0.602, 0.75, and 0.927). In ovariectomy + risedronate group, femur midshaft bone mineral density values were significantly higher than the values in ovariectomized group (p = 0.023). When compared to ovariectomized group, no significant difference was found with respect to femur midshaft bone mineral density values in groups treated with estrogen, raloxifene and clomiphene (p = 0.306, 0.808, and 0.095).

Conclusions

While risedronate sodium prevented the decrease in bone mineral density in ovariectomized rats, atorvastatin maintained mechanical characteristics of bone and also prevented the decrease in bone mineral density as risedronate sodium.  相似文献   
69.
Neuroendocrine (NE) carcinoma of the breast is extremely rare and constitutes less than 0.1% of all breast tumors. Only a few studies are currently available in the literature and a standard approach to treating this tumor has yet to be established. The aim of this study was to apply pathological treatment modalities in clinical practice and to select the most appropriate treatment accordingly. Six female patients were diagnosed with primary NE carcinoma of the breast. The patients underwent modified radical mastectomy with axillary dissection. Pathological specimens were stained with hematoxylin and eosin and an immunohistochemical panel of antibodies [neuron-specific enolase (NSE), chromogranin, synoptophysin, estrogen and progesterone receptor, c-erbB2 and Ki-67]. The results showed that tumor size ranged from 2 to 4.5?cm in diameter. Lymph node metastasis was detected in 4 (67%) patients. Estrogen and progesterone receptor expression was found in 5 (83%) patients. None of the patients expressed c-erbB2. Chromogranin was found to be positive in 5 (83%) patients. Synoptophysin expression was detected in 5 (83%) patients. NSE was stained in 4 (67%) patients. An intraductal component was found in 5 (83%) patients. Lymphovascular invasion was found in 5 (83%) patients. Adjuvant chemotherapy was administered to patients with a Ki-67 index of ≥10%. Radiotherapy was administered to 4?(67%)?patients, and 4?(67%) patients received hormonal therapy. The mean follow-up time was 31.1?months (range?12-52). All 6 patients survived, although following chemotherapy and tamoxifen, the disease progressed in 1?patient who received second-line hormonal therapy. In conclusion, NE carcinoma of the breast is a distinct entity. Management of this rare tumor may include surgery and radiotherapy depending on the size of the tumor and lymph node status. However, the exact role of chemotherapy and hormonal therapy has yet to be established. Adjuvant chemotherapy is recommended for patients with a Ki-67 index of ≥10%, and hormonal treatment appears to be feasible in patients who are positive for estrogen and/or progesterone receptor.  相似文献   
70.

Background

The main goal of this study was to evaluate the feasibility and effectivity of triweekly docetaxel/cisplatin followed by weekly docetaxel/cisplatin concomitantly with radiotherapy with or without surgery in locally advanced non–small-cell lung cancer (NSCLC) patients.

Materials and Methods

Thirty five patients with locally advanced NSCLC were enrolled. Combination chemotherapy with triweekly docetaxel/cisplatin (75 mg/m2) was administered as induction regimen. After induction chemotherapy, patients were evaluated for surgery if their disease subsequently downstaged. Six cycles of weekly docetaxel/cisplatin (20 mg/m2) concurrently with radiotherapy up to a 60 Gy were administered after induction chemotherapy with or without surgery. Response, toxicity, time-to-progression and overall survival were evaluated.

Results

Twelve patients with stage IIIA-N2 and 23 patients with stage IIIB-T4N0-2 were evaluated (median age, 54 years). After 94 cycles of induction chemotherapy, partial response was achieved in 20 patients, 9 patients had stable disease and six had progressive disease. After overall treatment, 6 patients achieved complete response, 19 patients had partial response, 8 patients had progressive disease, and 2 patients had stable disease. Two patients experienced grade 3-4 pulmonary toxicity and 1 patient experienced grade 3 esophageal toxicity. Six patients underwent surgery. Median overall survival for all patients was 15 months and time-to-progression was 13 months with a median follow-up of 22 months.

Conclusion

Triweekly docetaxel plus cisplatin followed by weekly docetaxel plus cisplatin concomitantly with radiotherapy is effective and feasible and seems to be an alternative option for patients who have locally advanced NSCLC. Surgery may provide additional benefit for patients whose disease adequately downstaged after induction chemotherapy.  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