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   2615篇
  免费   190篇
  国内免费   18篇
耳鼻咽喉   21篇
儿科学   60篇
妇产科学   34篇
基础医学   325篇
口腔科学   61篇
临床医学   214篇
内科学   827篇
皮肤病学   45篇
神经病学   192篇
特种医学   120篇
外科学   332篇
综合类   11篇
预防医学   73篇
眼科学   17篇
药学   159篇
中国医学   1篇
肿瘤学   331篇
  2024年   5篇
  2023年   48篇
  2022年   90篇
  2021年   155篇
  2020年   68篇
  2019年   104篇
  2018年   111篇
  2017年   95篇
  2016年   82篇
  2015年   95篇
  2014年   102篇
  2013年   122篇
  2012年   168篇
  2011年   161篇
  2010年   111篇
  2009年   84篇
  2008年   120篇
  2007年   110篇
  2006年   103篇
  2005年   91篇
  2004年   81篇
  2003年   96篇
  2002年   75篇
  2001年   47篇
  2000年   41篇
  1999年   50篇
  1998年   21篇
  1997年   17篇
  1996年   9篇
  1995年   5篇
  1994年   6篇
  1993年   11篇
  1992年   37篇
  1991年   39篇
  1990年   44篇
  1989年   41篇
  1988年   32篇
  1987年   25篇
  1986年   22篇
  1985年   29篇
  1984年   15篇
  1983年   11篇
  1982年   5篇
  1981年   5篇
  1980年   4篇
  1979年   5篇
  1977年   3篇
  1976年   8篇
  1973年   3篇
  1965年   3篇
排序方式: 共有2823条查询结果,搜索用时 15 毫秒
41.
42.
Pulmonary inflammatory pseudotumor is rare. A 34-year-old woman visited our hospital due to an abnormal chest shadow. Computed tomograhy showed a nodule in the right upper lobe. Bronchoscopy showed a polypoid endobronchial nodule obstructing most of the orifice of B2a. The nodule was white, glossy, and smooth, and it seemed to be covered with bronchial mucosa. However, transbronchial biopsy could not facilitate a diagnosis. To obtain a definitive diagnosis, we performed lobectomy of the right upper lobe using video-assisted thoracic surgery and removed the nodule completely. The pathologic diagnosis made during surgery was inflammatory pseudotumor. Immunohistochemical examination showed proliferating spindle cells were positive for vimentin and smooth muscle actin, but negative for epithelial markers. These findings were consistent with the staining pattern of inflammatory pseudotumor previously reported. Careful follow-up is necessary to detect any sign of local recurrence and distant metastases.  相似文献   
43.
We investigated the time-course changes in bone destruction in rats with collagen-induced arthritis (CIA). The synovial–cartilage junction (SCJ) and epiphyseal bone marrow of the femoral posteromedial condyle in CIA rats were evaluated histologically and immunohistologically at 2, 3, 4, 6, and 8 weeks after sensitization. Two weeks after sensitization, tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells formed resorption lacunae on the lateral side of the cortical bone under the SCJ. No resorption lacunae were observed in bone marrow. Three weeks after sensitization, resorption lacunae on the lateral side of the cortical bone expanded, but no bone marrow invasion by pannus was observed. In bone marrow, many TRAP-positive multinuclear cells appeared and formed resorption lacunae in subchondral bone. Four weeks after sensitization, cortical bone was destroyed, and pannus had invaded the bone marrow. After six weeks, trabecular bone and subchondral bone plate were extensively resorbed by TRAP-positive cells. Bone destruction in CIA began with the appearance of TRAP-positive cells on the lateral side of the cortical bone under the SCJ, followed by the TRAP-positive multinuclear cells in bone marrow, which were morphologically unconnected to the SCJ lesions. These histological findings suggested that bone destruction in the early stage of arthritis occurred in two anatomically different regions.  相似文献   
44.
This study aimed to perform cluster analysis in patients with chronic pain to extract groups with similar circadian rhythms and compare neuropathic pain and psychological factors among these groups to identify differences in pain-related outcomes. A total of 63 community-dwellers with pain lasting at least 3 months and Numerical Rating Scale scores of ≥2 were recruited from 3 medical institutions. Their pain circadian rhythms were evaluated over 7 days by measuring pain intensity at 6-time points per day using a 10-cm visual analog scale. Cluster analysis was performed using 6 variables with standardized visual analog scale values at 6-time points for individual participants to extract groups with similar pain circadian rhythms. The results of the Neuropathic Pain Symptom Inventory and psychological evaluations in each group were compared using the Kruskal–Wallis test. The results revealed 3 clusters with different circadian rhythms of pain. The total and evoked pain subscale Neuropathic Pain Symptom Inventory scores differed among the 3 clusters. The results suggest that a thorough understanding of circadian pain rhythms in chronic pain patients may facilitate the performance of activities of daily living and physical exercise from the perspective of pain management.  相似文献   
45.
Amyloidosis associated with chronic lymphocytic leukemia.   总被引:2,自引:0,他引:2  
Chronic lymphocytic leukemia (CLL), the most common form of leukemia in Western countries, rarely induces glomerular disease, but membranoproliferative glomerulonephritis or immunotactoid glomerulopathy has been reported. The proliferating cells in CLL are of mature B-cell origin and produce monoclonal immunoglobulin (Ig), thus leading to various kinds of autoimmune disorders or immunotactoid glomerulopathy. Although there have been a few reported cases of amyloidosis accompanying CLL, the type of amyloid fibrils has not been demonstrated nor described in detail, particularly regarding monoclonal Ig productivity. We report a rare case of amyloidosis associated with CLL, in which we detected ?-light chain type monoclonal Ig in the sera, urine, and on the surface membrane of lymphocytes, and discuss an association between monoclonal Ig-related disease and non-Hodgkin's lymphoma.  相似文献   
46.
Sinus of Valsalva aneurysm (SVA) arises frequently in the right coronary sinus, and ventricular septal defect (VSD) is a prevalent coexistent cardiac abnormality. A 38-year-old asymptomatic male diagnosed with VSD on cardiac catheterization in his childhood, was referred to our hospital for the change in intensity of his cardiac murmur pointed out by his family physician. A grade V continuous murmur was auscultated with a thrill loudest at the forth left sternal border. Although, transthoracic and transesophageal echocardiography and cardiac catheterization have showed the ruptured right coronary sinus aneurysm, it was difficult to demonstrate coexistence of a doubly committed subarterial VSD. Three-dimensional echocardiography could provide clear images for diagnosis of the VSD closely adjacent to the ruptured SVA. The defect was confirmed at surgery.  相似文献   
47.
We report an unexpected cause of a febrile patient with huge splenomegaly. A 32-year-old patient with fever and huge splenomegaly was admitted to our hospital. Diagnostic splenectomy revealed that the enlarged spleen adhered strongly to the abdominal organs. Pathologically, the splenic parenchyma showed no malignant cells, and the soft tissue adjacent to the splenic hilum showed a proliferation of fibroblastic or myofibroblastic spindle cells with fibrosis and lymphoplasmacytic infiltration. These findings lead to a diagnosis of peritoneal fibrosis, and an administration of 50 mg/day of prednisolone alleviated all the symptoms. The differential diagnosis of huge splenomegaly with fever usually includes hematolymphoid malignancies and infectious diseases; however, our case was diagnosed as idiopathic retroperitoneal fibrosis. Our case suggests that when we see patients with fever and huge splenomegaly, differential diagnosis should include retroperitoneal fibrosis.  相似文献   
48.
Asian H5 highly pathogenic avian influenza viruses (HPAIVs) that possess the clade 2.3.4.4 HA gene have been identified in wild birds and poultry since late 2014 in both Europe and North America (N. America). Clade 2.3.4.4 H5 HPAIVs of the H5N8 subtype have been isolated in both regions, whereas reassortment viruses with NA N1 and N2 subtypes of the North American (N. American). avian lineage have only been identified in N. America. The HA genes of those isolates were closely related to genes of the HPAIVs that have caused massive outbreaks in poultry in Korea since January 2014. The outbreaks caused by those viruses and the genetic relatedness of their HA and NA genes are reviewed in this study. Although the illegal movement of poultry and poultry products cannot be ruled out as a cause of intercontinental and intracontinental dissemination of clade 2.3.4.4 H5 HPAIVs during the winter of 2014–2015, transmission of the viruses by infected migratory birds appears to be a more plausible mechanism for their dissemination. In particular, the involvement of migratory birds in HPAIV transmission between Asia and N. America is highly likely because of the reassortments between H5N8 HPAIV and the N. American lineage avian influenza viruses. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
49.
A linear combination fitting in sulfur K-edge X-ray absorption near edge structure (S-XANES) measurements reveals each fraction of monosulfidic, disulfidic and polysulfidic linkages in solvent extracted sulfur cross-linked isoprene rubbers. The sulfidic linkage of a disulfidic type is found for the first time to be dominant when zinc stearate and N-(1,3-benzothiazol-2-ylsulfanyl)cyclohexanamine are used as the activator and accelerator, respectively, for the sulfur cross-linking reaction at 140 °C. The presence of the bridging bidentate zinc/stearate complex as an intermediate for the sulfur cross-linking reaction is supposed to induce the generation of abundant disulfidic linkages in the rubber networks. This unexpected observation is of use for the material design of high performance rubber products with anti-aging and thermal stabilities. S-XANES is a powerful tool that was used to reveal the characteristics of the sulfur cross-linking of rubber. These results will contribute to the development of rubber science and technology.

The bridging bidentate zinc/stearate complex, an intermediate for the sulfur cross-linking reaction, supposedly induces an abundance of disulfidic linkages in the rubber network.  相似文献   
50.
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