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   7302篇
  免费   690篇
  国内免费   131篇
耳鼻咽喉   82篇
儿科学   501篇
妇产科学   162篇
基础医学   1520篇
口腔科学   173篇
临床医学   454篇
内科学   494篇
皮肤病学   260篇
神经病学   106篇
特种医学   305篇
外国民族医学   7篇
外科学   999篇
综合类   525篇
预防医学   66篇
眼科学   49篇
药学   265篇
中国医学   88篇
肿瘤学   2067篇
  2024年   23篇
  2023年   123篇
  2022年   181篇
  2021年   312篇
  2020年   293篇
  2019年   281篇
  2018年   260篇
  2017年   240篇
  2016年   272篇
  2015年   309篇
  2014年   443篇
  2013年   532篇
  2012年   326篇
  2011年   332篇
  2010年   279篇
  2009年   283篇
  2008年   332篇
  2007年   322篇
  2006年   309篇
  2005年   237篇
  2004年   255篇
  2003年   180篇
  2002年   158篇
  2001年   174篇
  2000年   144篇
  1999年   133篇
  1998年   130篇
  1997年   153篇
  1996年   105篇
  1995年   89篇
  1994年   100篇
  1993年   84篇
  1992年   69篇
  1991年   75篇
  1990年   49篇
  1989年   70篇
  1988年   39篇
  1987年   36篇
  1986年   52篇
  1985年   60篇
  1984年   53篇
  1983年   31篇
  1982年   42篇
  1981年   36篇
  1980年   28篇
  1979年   31篇
  1978年   21篇
  1977年   15篇
  1976年   13篇
  1975年   7篇
排序方式: 共有8123条查询结果,搜索用时 15 毫秒
11.
We report the case of a patient with a 13-year history of pemphigus vulgaris (PV) treated with immunosuppressive agents, prednisone and mycophenolate mofetil who had developed lesions of Kaposi's sarcoma (KS) on a sole plaque of PV that had been previously treated with intralesional injections of steroids. The lesions were surgically removed and polymerase chain reaction (PCR) demonstrated human herpesvirus-8 (HHV-8) DNA. There were neither recurrences nor later dissemination of KS following gradual decrease of the immunosuppressive therapy. We suggest that the treatment with intralesional steroids may have influenced the local reactivation of a latent infection of the virus, determining the appearance of this localized KS.  相似文献   
12.
目的艾滋病(AIDS),是严重危害人类健康的疾病,临床上症状多变,应提高对AIDS的认识。现将作者在西非工作期间收治的142例AIDS病例的临床表现作一介绍。方法病例均为当地黑人居民,男性89例,女性53例,年龄14~45岁,平均年龄27.65岁。用酶联免疫吸附法和快速法检测患者血清中HIV—1和 HIV—2抗体。结果 HIV—1型25例(35.00%);HIV-2型74例(52.11%);混合型32例(22.53%)。临床表现为脑膜脑炎或脑炎7例(4.93%);肺型27例(19.01%);胃肠道感染84例(59.15%):包括急性48例(33.80%),慢性24例(16.90%),急腹症12例(8.45%);皮肤粘膜损害18例(12.68%):卡波齐肉瘤6例(4.23%),带状疱疹2例(1.41%),皮炎10例(7.04%),病死率19.72%(28/142)。其传播途径以性传播为主,高达78.87%(112/142),其次是密切生活接触,未发现吸毒或输血者。结论艾滋病病死率高,病情复杂,且目前尚无特效药物,必须引起医护人员高度重视。  相似文献   
13.
复方华蟾胶囊抗小鼠肿中瘤作用的实验研究   总被引:2,自引:0,他引:2  
目的了解复方华蟾胶囊抗小鼠移植性肿瘤的作用.方法以小鼠肝癌22(H22)、小鼠肉瘤180(S180)为瘤株,应用动物移植性肿瘤的体内试验法对药物进行抗癌药效学试验.结果复方华蟾胶囊灌胃4,2 g/kg@d,连续14 d,对小鼠移植性肝癌实体型生长有明显的抑制作用,抑瘤率分别为38.09%,30.95%.对小鼠移植性S180实体型生长有明显的抑制作用,抑瘤率分别为34.7%,30.08%.复方华蟾胶囊对荷瘤小鼠的胸腺和脾脏重量无影响.结论复方华蟾胶囊在试验条件下有一定抗肿瘤作用.  相似文献   
14.
The term synovial sarcoma was first proposed for the histologically well defined entity by Knox in 1936. The name was proposed due to the fact that at least the cases reported in the early part showed some resemblance of the tumour to normal synovial tissue histologically. Thereafter, tumours have been diagnosed from areas without synovial tissue. The diagnosis of monophasic tumours can be difficult and immunostains appear to be a good diagnostic tool in those cases. The occurrence in the mandible is extremely rare. This is a case of synovial sarcoma arising in the condyle involving most of the ramus. The tumour was diagnosed as synovial sarcoma with predominant spindle cell component by correlation of histopathology with immunostains (cytokeratin, epithelial membrane antigen, actin and desmin). The patient has been treated with surgery and radiotherapy.  相似文献   
15.
The advent of recombinant DNA technology has led to the identification in the DNA of normal animal cells of over 30 proto-oncogenes that are homologous to retroviral transforming genes. One of these encodes a protein kinase (pp60c-src) of unknown function, that is preferentially synthesized in brain and neural retina. Here the expression of pp60c-src in the peripheral nervous system was examined in sensory neurons from chick dorsal root ganglia with antisera raised against the transforming protein of Rous sarcoma virus (pp60v-src) expressed in Escherichia coli carrying the cloned v-src gene. This antiserum recognizes pp60c-src specifically in normal chicken cells. Western immunoblotting showed that dorsal root ganglia of stage 30 (day 6.5) chick embryos contained elevated levels of pp60c-src. Immunoperoxidase staining of neuron-enriched cultures prepared from chick dorsal root ganglia showed pp60c-src immunoreactivity in cells with neuronal morphology; flat, fibroblastic cells contained no detectable immunoreactivity. Indirect double immunofluorescence with pp60src antibodies and monoclonal antibodies against the 200-kD subunit of neurofilament protein confirmed that the cells expressing pp60c-src were neurons. Ninety-six percent of the neurofilament-positive cells were immunoreactive with pp60src antibodies, and conversely, all pp60c-src-positive cells were immunoreactive with neurofilament antibodies. pp60c-src immunofluorescence appeared to be distributed over the cell body, processes, and growth cones. These results clearly demonstrate that pp60c-src is a product of neurons and is expressed in sensory neurons in culture.  相似文献   
16.
Acute myelogenous leukemia (AMU is a hematologic disorder that is characterized by an abnormal proliferation of immature myeloid cells. Granulocytic sarcomas are clusters of leukemic myeloid cells that may develop as a result of AML. Oral manifestations of AML are common and often involve enlargements of the gingiva and/or mucosal tissue from direct leukemia cell infiltration. We describe the case history of a 50-year-old man who had an ulcera-tive lesion of the oral mucosa that was determined to be a granulocytic sarcoma of AML-M0 subtype. The combination of both the subtype and clinical presentation of the leukemia makes this presentation unusual, and to the best of our knowledge, of a type that has not been previously reported in the literature.  相似文献   
17.
Langerhans cell sarcoma in a patient who underwent transplantation   总被引:1,自引:0,他引:1  
Langerhans cell sarcoma is a rare, aggressive tumour that may metastasize to many organs, likely leading to death of the patient within 1 year. We present the first case described in the literature in a patient who underwent transplantation.  相似文献   
18.
Multidrug resistance (MDR) is an important problem in chemotheraphy for neoplastic disease. In humans, MDR is mainly mediated by P-glycoprotein (P-gp), a product of theMDR1 gene, which acts as a transmembrane protein pump and eliminates chemotherapeutic agents from the cells. Expression of P-gp was immunohistochemically studied by using two monoclonal antibodies, JSB-1 and C-219, on paraffin-embedded sections from 55 patients with soft-tissue sarcoma. The histological diagnosis of tumors was malignant fibrous histiocytoma in 24 cases, liposarcoma in 9, synovial sarcoma in 7, malignant neurogenic tumors in 6, leiomyosarcoma in 5, others in 4. The histological grade was determined on the basis of criteria previously proposed by us. Out of 55 cases, 34 (62%) were positive for P-gp expression. There was a significant difference in P-gp expression between high-grade (90%) and intermediate and low-grade tumors (46%) (P<0.005). Tumors expressing P-gp had a less favorable prognosis than P-gp-negative tumors in the high- and intermediate-grade tumors. The current study demonstrated that the estimation of P-gp expression could be used to select appropriate therapeutic modalities.Abbreviations MDR multidrug resistance - P-gp P-glyco-protein  相似文献   
19.
The CD30 is a surface molecule expressed by Th2-type lymphokine-producing T cells upon activation. CD30-expressing activated T cells release a soluble form of the molecule, which can be detectable both in vitro and in vivo. In the present study, high levels of soluble CD30 were found in peripheral blood and synovial fluid from patients with RA. However, CD30+ CD3+ cells, either CD4+ or CD8+, were significantly present in synovial fluid, but not in peripheral blood, of RA patients. Serum values of soluble CD30 were higher in active than inactive RA patients and directly correlated with rheumatoid factor serum titres. These data strongly support an involvement of CD30+ T cells in the immune processes of rheumatoid synovitis, and may suggest a relationship between Th2-type cytokine-secreting T cells and the pathological response in RA.  相似文献   
20.
The purpose of this study was to validate the hypothesis of neural histogenesis of Ewing's sarcoma of bone and related tumors by light microscopic, electron microscopic, and immunohistochemical analysis. We studied 32 round-cell sarcomas (19 cases of Ewing's sarcoma of bone, 3 extraskeletal Ewing's sarcomas, 5 peripheral primitive neuroectodermal tumors (PNET) and 5 cases of unclassified small round-cell type of neurogenic sarcoma (NS). Immunoreactivity for MIC2 was observed in all cases of Ewing's sarcoma and PNET, and in 1 cases of NS. Positive immunoreactivity for neural markers (NSE, synaptophysin, S-100) was found frequently in some tumors. Ultrastructurally, some specific features of neural differentiation, such as a fragmented basal lamina and neurosecretory granule-like particles, were found even in typical cases of Ewing's sarcoma of bone, which presented without a rosette arrangement and were almost negative for neural immuno-markers, but positive for MIC2. These ultrastructural neural features were observed less frequently in Ewing's sarcoma of bone than in PNET and NS. However, no significant correlation was demonstrated between the immunoreactivity for neural markers and the ultrastructural and histological neural features. These results support the hypothesis of a neural origin of Ewing's sarcoma and related neoplasms, and suggest that some overlapping entity could persist in PNET and Ewing's sarcoma and that this entity could be seen in histological and immunohistochemical studies of both tumors.  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