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   889篇
  免费   46篇
  国内免费   2篇
耳鼻咽喉   10篇
儿科学   29篇
妇产科学   8篇
基础医学   104篇
口腔科学   52篇
临床医学   130篇
内科学   181篇
皮肤病学   7篇
神经病学   87篇
特种医学   38篇
外科学   114篇
综合类   3篇
预防医学   41篇
眼科学   20篇
药学   34篇
中国医学   9篇
肿瘤学   70篇
  2023年   16篇
  2022年   30篇
  2021年   49篇
  2020年   28篇
  2019年   46篇
  2018年   33篇
  2017年   22篇
  2016年   34篇
  2015年   30篇
  2014年   25篇
  2013年   45篇
  2012年   73篇
  2011年   79篇
  2010年   37篇
  2009年   40篇
  2008年   39篇
  2007年   31篇
  2006年   38篇
  2005年   22篇
  2004年   28篇
  2003年   24篇
  2002年   26篇
  2001年   23篇
  2000年   17篇
  1999年   20篇
  1998年   6篇
  1997年   2篇
  1996年   7篇
  1995年   4篇
  1994年   2篇
  1993年   4篇
  1992年   10篇
  1991年   12篇
  1990年   4篇
  1989年   3篇
  1988年   3篇
  1986年   1篇
  1984年   2篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1972年   2篇
  1971年   1篇
  1970年   4篇
  1969年   1篇
  1968年   2篇
  1967年   3篇
  1966年   2篇
  1965年   1篇
  1964年   1篇
排序方式: 共有937条查询结果,搜索用时 15 毫秒
1.
We assessed the occurrence of atypical adenomatous hyperplasia (AAH) in whole lung lobes with primary cancer lesions. Following surgical resection, tissue specimens were sliced to a thickness of 4 mm (3,641 specimens from 61 cases; mean = 59.7 specimens per case). A total of 119 AAH foci were found and an association was evident in 25 (57%) of 44 adenocarcinomas, 3 (30%) of 10 squamous cell carcinomas, and 2 (29%) of 7 other lung cancers. Histologic evaluation showed that 108 AAH foci were categorized as low-grade and the other 11 as high-grade AAH. These 11 foci of high-grade AAH were present in 7 patients with adenocarcinoma, and in 1 patient there was a synchronous double primary lung adenocarcinoma. High-grade AAH was closely associated with bronchioloalveolar carcinoma (BAC) type adenocarcinoma, and low-grade AAH with non-BAC adenocarcinoma. The mean +/- SD Ki-67 labeling index in high-grade AAH (3.5%+/-2.9%) was significantly higher than for the low-grade index (1.4%+/-1.6%). We propose that foci of high- but not low-grade AAH may be potential precursor lesions of lung adenocarcinoma, especially with the BAC component.  相似文献   
2.
Systemic spread of primary intracranial neoplasms is rare and may be due to ventriculoperitoneal shunt (VPS). The most common tumors to metastasize via VPS are germinoma of the pineal gland and medulloblastoma. We report a case of 16-yr-old girl with central nervous system malignant melanosis who developed subsequent peritoneal implants via VPS. To the best of our knowledge, this patient represents the third reported case of meningeal melanosis or melanoma which metastasized to the peritoneal cavity via VPS. The VPS should be considered as possible mode of systemic spread in patients with primary cranial malignancy. © 1995 Wiley-Liss, Inc.  相似文献   
3.
Soluble human interleukin-6 receptor (sIL-6R) was measured in the serum of 30 healthy individuals, 32 individuals with monoclonal gammopathy of undetermined significance (MGUS), 20 patients with early multiple myeloma (MM) and 54 patients with overt MM. The serum activity recognized by an immunoradiometric assay was determined to be sIL-6R, because of its binding capacity to IL-6 and its molecular mass of 55 kDa. All sera of healthy individuals contained sIL-6R (mean value: 89 ng/ml, range 17-300 ng/ml). Serum sIL-6R levels were increased by 51% in patients with MGUS (mean value: 135 ng/ml, p<0.005), by 44% in patients with early myeloma (mean value: 128 ng/ml, p<0.001) and by 116 % in patients with overt MM (mean value: 193 ng/ml, p<0.001). In patients with MM, a complete lack of correlation (p>0.7) was found between serum sIL-6R levels and other previously recognized prognostic factors in this disease, particularly serum IL-6 levels and those factors related to tumor cell mass. The independence of serum sIL-6R levels on tumor cell mass was directly demonstrated by studying four patients with MM treated with autologous bone marrow transplantation for periods of between 320 and 760 days. These levels were found to be remarkably stable and constant, independent of whether patients relapsed or achieved complete remission. Finally, physiological concentrations of sIL-6R were found to increase by tenfold the sensitivity of human myeloma cell lines to IL-6. These observations suggest a high control of the sIL-6R level in vivo, and, possibly, an important functional role of this circulating protein in patients with monoclonal gammopathies.  相似文献   
4.
A case of primary leptomeningeal fibrosarcoma metastatic to the thyroid gland, diagnosed by fine needle aspiration biopsy is described. The patient, a 39-year-old women was initially diagnosed with a leptomeningeal fibrosarcoma. Sections of the primary tumor studied by electron microscopy showed that the tumor cells have the ultrastructure features of a fibroblast. She underwent tumor resection, followed by chemotherapy and local radiotherapy. Four months later, she presented with dysphagia. Ultrasonography confirmed the presence of a 2-cm mass in the right lobe of thyroid. A fine needle aspiration biopsy was performed. Light microscopy showed interwoven bundles of neoplastic spindle cells similar to the primary tumor, consistent with a metastatic fibrosarcoma. To our knowledge, this is the first report of a primary meningeal fibrosarcoma that metastasized to the thyroid gland, which was diagnosed by a fine needle aspiration biopsy.  相似文献   
5.
6.
BackgroundAcute exacerbations of chronic obstructive pulmonary disease (AECOPD) are serious complications that often require immediate intervention in an emergency department (ED). The aim of this study was to investigate the effect of intravenous magnesium sulphate as an adjuvant in the treatment of AECOPD in the ED.MethodsIn a double-blind, randomized clinical trial, a total of 60 patients with AECOPD presenting to the ED of Imam Khomeini Hospital in Sari, Iran, were included. The study was conducted between September 2016 and February 2018. Eligible patients were randomly allocated into two groups of intervention and control. Patients in the intervention and control groups received intravenous infusion of magnesium sulfate (2 gr) or normal saline over 30 minutes, respectively. For all patients, Borgdyspnea score, forced expiratory volume in one second (FEV1) result and clinical variables of interest were evaluated before the beginning of the intervention, and also 45 minutes and 6 hours after the commencement of intervention.ResultsRegardless of time of evaluation, pulse rate (PR), respiratory rate (RR) and Borg score in intervention group was lower than control group. Also, FEV1 and SPO2 were greater in intervention group compared to control group. However, these differences were not statistically significant (between-subject differences or group effect) (p<0.001). The trends of FEV1, SPO2, PR, RR and Borg score were similar between two groups of study (no interaction effect; P>0.05).ConclusionAccording to the results of this study, it seems that using intravenous magnesium sulfate has no significant effect on SPO2, FEV1, RR, and PR of patients with AECOPD who presented to ED.  相似文献   
7.
8.
Non-small cell lung cancer (NSCLC) is one of the most common types of cancer in the world and has a 5-year survival rate of ~20%. Immunotherapies have shown promising results leading to durable responses, however, they are only effective for a subset of patients. To determine the best therapeutic approach, a thorough and in-depth profiling of the tumour microenvironment (TME) is required. The TME is a complex network of cell types that form an interconnected network, promoting tumour cell initiation, growth and dissemination. The stroma, immune cells and endothelial cells that comprise the TME generate a plethora of cytotoxic or cytoprotective signalling pathways. In this review, we discuss immunotherapeutic targets in NSCLC tumours and how the TME may influence patients' response to immunotherapy.  相似文献   
9.
The purpose of the present article is to study the bending strength of glulam prepared by plane tree (Platanus Orientalis-L) wood layers adhered by UF resin with different formaldehyde to urea molar ratios containing the modified starch adhesive with different NaOCl concentrations. Artificial neural network (ANN) as a modern tool was used to predict this response, too. The multilayer perceptron (MLP) models were used to predict the modulus of rapture (MOR) and the statistics, including the determination coefficient (R2), root mean square error (RMSE), and mean absolute percentage error (MAPE) were used to validate the prediction. Combining the ANN and the genetic algorithm by using the multiple objective and nonlinear constraint functions, the optimum point was determined based on the experimental and estimated data, respectively. The characterization analysis, performed by FTIR and XRD, was used to describe the effect of the inputs on the output. The results indicated that the statistics obtained show excellent MOR predictions by the feed-forward neural network using Levenberg–Marquardt algorithms. The comparison of the optimal output of the actual values obtained by the genetic algorithm resulting from the multi-objective function and the optimal output of the values estimated by the nonlinear constraint function indicates a minimum difference between both functions.  相似文献   
10.
Pathogenic mutations in the FARSB gene are associated with neurodevelopmental disorder involving the brain, liver, and lungs. We report genetic analysis of a family including two affected members with this disorder, which revealed a homozygous pathogenic missense variant, FARSB: NM_005687.4:c.853G > A:p.E285K in both affected patients. The parents were heterozygous for this variant.  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