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   2913篇
  免费   204篇
  国内免费   6篇
耳鼻咽喉   7篇
儿科学   45篇
妇产科学   28篇
基础医学   579篇
口腔科学   21篇
临床医学   270篇
内科学   578篇
皮肤病学   45篇
神经病学   482篇
特种医学   68篇
外科学   397篇
综合类   16篇
预防医学   149篇
眼科学   34篇
药学   183篇
中国医学   1篇
肿瘤学   220篇
  2023年   26篇
  2022年   32篇
  2021年   76篇
  2020年   39篇
  2019年   57篇
  2018年   67篇
  2017年   37篇
  2016年   55篇
  2015年   84篇
  2014年   95篇
  2013年   158篇
  2012年   204篇
  2011年   235篇
  2010年   131篇
  2009年   126篇
  2008年   173篇
  2007年   180篇
  2006年   180篇
  2005年   169篇
  2004年   153篇
  2003年   128篇
  2002年   134篇
  2001年   60篇
  2000年   59篇
  1999年   70篇
  1998年   33篇
  1997年   27篇
  1996年   17篇
  1995年   13篇
  1994年   17篇
  1993年   14篇
  1992年   28篇
  1991年   32篇
  1990年   29篇
  1989年   19篇
  1988年   16篇
  1987年   22篇
  1986年   14篇
  1985年   17篇
  1984年   7篇
  1983年   7篇
  1982年   8篇
  1981年   5篇
  1979年   7篇
  1978年   5篇
  1975年   6篇
  1974年   7篇
  1973年   7篇
  1972年   6篇
  1971年   5篇
排序方式: 共有3123条查询结果,搜索用时 31 毫秒
31.
32.
In this study the functional effectiveness of in vivo macrophage depletion using liposome-encapsulateddichloromethylene bisphosphonate (C12MBP) was examined in the chicken. The main target organs forsystemic liposome-encapsulated C12MBP treatment are the spleen and the liver. Intravenous treatment withC12MBP of B21/B21 chickens, genetically resistant to Marek's disease (MD), before challenge with the very virulent strain RB-lB, increased viral load in the blood and spleen after the first week and up to 6 weeks postinfection. In addition, C12MBP treatment dramatically increased tumour incidence and tumour load, especially in the spleens and livers of sick animals, but without affecting MD-specific mortality of B21/B21 cickens infected with RB-1B at 12 days of age. Nitric oxide (NO) is an important effector of the macrophage and has antiviral and antitumoural properties. NO has been shown to be one of the mechanisms triggered in resistance to Marek's disease. Intravenous treatment with Cl2MBP before infection with RB-1B induced a long-lasting decrease in numbers of macrophages and reduction in splenic inducible NO production associated with an absence of nitrate induction in the serum (up to 6 weeks pi). These results do not identify macrophage and NO production as major effector components in genetic resistance to Marek's disease, but underline their roles in limiting viraemia and tumour development in organs such as the spleen and the liver.  相似文献   
33.
Studies by comparative genome hybridization have suggested that 5p amplification is related to tumor progression in urinary bladder cancer. In this study seven genes (TAS2R, ADCY2, DNAH5, CTNND2, TRIO, ANKH, and MYO10) located to 5p15.31-5p15.1 were analyzed by fluorescence in situ hybridization using a tissue microarray containing samples from tumors and cell lines with known 5p amplification by comparative genome hybridization. Amplification frequency was highest for TRIO, which maps to 5p15.2 and encodes a protein with a putative role in cell-cycle regulation. To further investigate the role of TRIO amplification in bladder cancer, a tissue microarray containing samples from 2317 bladder tumors was used for fluorescence in situ hybridization analysis. TRIO amplification was strongly associated with invasive tumor phenotype, high tumor grade, and rapid tumor cell proliferation (Ki67 LI) (P < 0.0001 each). Only 7 of 456 pTaG1/G2 tumors (1.5%) but 62 of 485 pT1-4 carcinomas (12.8%) had TRIO amplification. TRIO amplification was not associated with poor prognosis. Using a frozen bladder tumor tissue microarray RNA in situ hybridization confirmed that TRIO is up-regulated in amplified tumors. It is concluded that TRIO up-regulation through amplification has a potential role in bladder cancer progression.  相似文献   
34.
Four cases of placental candidiasis, an uncommon complication of rupture of the membranes, are presented. In addition to chorioamnionitis, in one of these cases villitis was also observed. Villitis is a rare occurrence in Candida infection and this represents only the second case in the literature. The involvement of villi may be suggestive of blood-borne infection. However, since neither the mother nor the foetus presented any signs of systemic dissemination, the authors suggest a hypothesis of contamination of the villi from foci of chorioamnionitis.  相似文献   
35.
To clarify how Abeta deposits induce secondary tauopathy, the presence of phosphorylated tau, glycogen synthase kinase 3alpha (GSK3alpha), GSK3beta, cyclin-dependent kinase 5 (CDK5), mitogen-activated protein kinase (MAPK) and fyn were examined in the Tg2576 brain showing substantial brain Abeta amyloidosis and behavioral abnormalities. Phosphorylated tau at Ser199, Thr231/Ser235, Ser396 and Ser413 accumulated in the dystrophic neurites of senile plaques. The major kinase for tau phosphorylation was GSK3beta. Smaller contributions of GSK3alpha, CDK5 and MAPK were suggested. Thus, brain Abeta amyloidosis has a potential role in the induction of tauopathy leading to the mental disturbances of Alzheimer's disease.  相似文献   
36.
The European Journal of Health Economics - Cancer patients have one of the highest health care expenditures (HCE) at the end of life. However, the growth of HCE at the end of life remains poorly...  相似文献   
37.
Eribulin is widely used in the treatment of metastatic breast cancer, with a manageable toxicity profile. This aggressive disease often requires systemic and local treatments, comprising surgery or radiotherapy. However, eribulin is usually discontinued during radiation therapy due to the lack of data concerning the safety of this combination, especially in the setting of repeat locoregional radiation therapy. Our patient was diagnosed with ER positive invasive ductal carcinoma of the left breast initially treated by surgery, radiation therapy, chemotherapy, and hormone therapy. She then received various lines of chemotherapy for multiple triple-negative relapses in the left axillary region. Since October 2020, she has been treated by eribulin. In order to improve local control, it was decided to add local radiation therapy to the region of recurrence in addition to systemic therapy. She underwent radiation therapy concomitantly with eribulin from February to March 2021. Treatment was very well tolerated, and no acute toxicity was reported. This is the first published case of repeat locoregional radiation therapy in combination with eribulin.  相似文献   
38.
Imaging of chest wall disorders.   总被引:10,自引:0,他引:10  
Pathologic processes that may involve the chest wall include congenital and developmental anomalies, inflammatory and infectious diseases, and soft-tissue and bone tumors. Many of these processes have characteristic radiologic appearances that allow definitive diagnosis. Sternal deformities can be visualized at radiography and their severity quantified with computed tomography (CT). In cervical rib, CT with multiplanar reconstruction may demonstrate relevant anatomic detail and the relationship between bone deformity and arterial compression. In Poland syndrome, radiography reveals an area of hyperlucency on the affected side, whereas CT demonstrates the absence of the greater pectoral muscle and clearly depicts associated musculoskeletal anomalies. Tuberculosis typically manifests at radiography and CT as osseous and cartilaginous destruction and soft-tissue masses with calcification and rim enhancement. Aspergillosis involving the chest wall manifests as pulmonary consolidations and permeative osteolytic changes of the rib and spine at CT and as an area of increased signal intensity at T2-weighted magnetic resonance (MR) imaging. Neurogenic tumors and hemangiomas also typically have high signal intensity at T2-weighted MR imaging. Apparent mass extension or unequivocal bone destruction seen at CT or MR imaging may indicate chest wall involvement by lymphoma. Radiologically, soft-tissue sarcomas typically appear as areas of soft-tissue density or attenuation, often associated with necrotic areas of low density or attenuation. At radiography, plasmacytoma typically manifests as well-defined, "punched-out" lytic lesions with associated extrapleural soft-tissue masses. Chondrosarcoma frequently appears as a large, lobulated excrescent mass arising from a rib with scattered flocculent calcifications characteristic of its cartilaginous mix. Familiarity with these radiologic features facilitates accurate diagnosis and optimal patient treatment.  相似文献   
39.
Even complex diagnostic tests may not establish aetiology and degree of erectile dysfunction (ED) in many patients. Therefore, we evaluated a self-report method with a restrictive focus to quality of erections which may yield information sufficient to make an aetiologic diagnosis. We studied 74 patients 25 to 75 years of age with untreated ED. Sexually stimulated erections were quantified and compared to duplexsonographically and clinically evaluated data from pharmacostimulated erections. Patients reported that there was a marked decrease in ability to penetrate the partner, to sustain an erection and of penile rigidity (p < 0.001). Parameters from duplexsonography and clinically assessed response to pharmacostimulation correlated (r = 0.72). Direct comparison of these data with quantified history showed no relation (r = 0.05). Using change in penile volume due to erection as a basis to compare with, showed significant correlation with quantified data from history (r = 0.26-0.34; p < 0.03) and measured parameters from pharmacostimulated erections (r = 0.44-0.55; p < 0.0001). Sexually- and pharmacostimulated erections are proportional to change in penile volume. Although there is a relation between erections emerging from both stimulations, quantifying history on sexually stimulated erections does not qualify to make an aetiologic diagnosis without using complex tests.  相似文献   
40.
Summary In benign hyperplasia marked -glucuronidase and N-acetyl--glucosaminidase activity was seen in the prostatic epithelium whereas the reactions for 5 other glycosidases were only slight or negative. The intensity of the reaction for the glycosidases in prostatic carcinoma was dependent upon the degree of the differentiation. The possible importance of glycosidases for the invasiveness of prostatic carcinoma is briefly discussed.  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