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   3967篇
  免费   190篇
  国内免费   31篇
耳鼻咽喉   26篇
儿科学   91篇
妇产科学   35篇
基础医学   926篇
口腔科学   50篇
临床医学   181篇
内科学   771篇
皮肤病学   161篇
神经病学   380篇
特种医学   123篇
外科学   542篇
综合类   10篇
预防医学   75篇
眼科学   132篇
药学   226篇
中国医学   7篇
肿瘤学   452篇
  2023年   21篇
  2022年   23篇
  2021年   84篇
  2020年   41篇
  2019年   75篇
  2018年   69篇
  2017年   55篇
  2016年   61篇
  2015年   72篇
  2014年   103篇
  2013年   123篇
  2012年   170篇
  2011年   195篇
  2010年   101篇
  2009年   98篇
  2008年   234篇
  2007年   215篇
  2006年   242篇
  2005年   302篇
  2004年   287篇
  2003年   308篇
  2002年   285篇
  2001年   55篇
  2000年   42篇
  1999年   69篇
  1998年   78篇
  1997年   83篇
  1996年   52篇
  1995年   62篇
  1994年   50篇
  1993年   55篇
  1992年   50篇
  1991年   27篇
  1990年   30篇
  1989年   43篇
  1988年   22篇
  1987年   25篇
  1986年   32篇
  1985年   20篇
  1984年   25篇
  1983年   22篇
  1982年   8篇
  1981年   12篇
  1980年   23篇
  1978年   16篇
  1977年   10篇
  1976年   11篇
  1975年   8篇
  1970年   8篇
  1969年   9篇
排序方式: 共有4188条查询结果,搜索用时 31 毫秒
1.
2.
BACKGROUND: To understand the immunopathological features of oral lichen planus (OLP), we analyzed the expression of chemokines in the epithelial cell layers. Methods: Epithelia from OLP or healthy gingiva were collected by laser microdissection. The chemokine and chemokine receptor expressions in the epithelia were analyzed by DNA microarray. RESULTS: High levels of MIP-3alpha/LARC/CCL20 and its receptor CCR6 were expressed in the lesional epithelia. Furthermore, DC-CK1/CCL18, ELC/CCL19, SDF-1/CXCL12 and CXCR4 expressions were also increased. Immunohistologial analysis showed that high numbers of Langerhans cells (LCs) were present in the epithelia of OLP. Lesional epithelia also expressed high levels of the ligands specific for CXCR3 (e.g. MIG/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11) and CCR5 (e.g. RANTES/CCL5). CONCLUSIONS: Infiltration of LCs is orchestrated by CCR6. Further, LCs residing in the lesional epithelia may be a mature phenotype. Moreover, infiltration of T cells in OLP could be mediated by signaling pathways through CXCR3 and CCR5.  相似文献   
3.
Surgical treatment for subacute pulmonary arterial thromboembolism has previously been considered to be inappropriate. We undertook a pulmonary arterial thrombectomy and removal of a floating right heart thrombus in a patient who had been symptomatic for over a month. The pulmonary arterial pressure, which had been equal to the systemic pressure preoperatively, decreased gradually and almost normalized one month postoperatively. Pulmonary perfusion scintigraphy revealed a dramatic improvement and the patient returned to normal life activities.  相似文献   
4.
OBJECTIVE: A joint study was undertaken by the Japanese Society of Renal Cancer to investigate the present status of partial nephrectomy in Japan and to speculate about what may be the indications for partial nephrectomy in patients with renal cell carcinoma. METHODS: Data were tabulated for 469 patients from participating medical institutions and various clinical factors were investigated with regard to disease progression (local recurrence and distant metastasis). RESULTS: Disease progression was observed in 21 patients (4.5%). No significant relation to disease progression was observed for sex, laterality, tumor histology, grade and tumor size. Although patients with solitary tumors displayed excellent prognosis irrespective of tumor diameter, patients with multiple tumors displayed a high likelihood of disease progression. Patients older than 77 years old and patients with imperative indication were found to have a poorer prognosis. CONCLUSION: In patients with solitary tumors, partial nephrectomy can be actively performed, even if the patient displays elective indications and the tumor is >4 cm in diameter. In patients displaying multiple tumors with imperative indications, the decision whether to perform partial nephrectomy should be made by the patients and their physicians after considering the impact on curability and the quality of life.  相似文献   
5.
Coiled bodies and interfascicular threads are conspicuous white matter abnormalities of brains of patients with progressive supranuclear palsy (PSP). Both structures are argyrophilic and immunoreactive for the microtubule-binding protein tau. This report concerns the ultrastructural localization of interfascicular threads and their relationship to coiled bodies in five PSP patients. We showed for the first time that abnormal tubules with a 13- to 15-nm diameter and fuzzy outer contours were the common structures of coiled bodies in the oligodendroglial perikarya and of interfascicular threads. Moreover, the tubules were immunolabeled by anti-tau antibodies. The abnormal tau-positive tubules of interfascicular threads were located in the inner loop of the myelin sheath. Our study further indicated that the thread-like structures in the white matter comprised, at least in part, oligodendroglial processes, and that they were also present in gray matter. We consider that the formation of coiled bodies in the perikarya and of interfascicular threads represents a common cytoskeletal abnormality of the oligodendroglia of PSP patients. Moreover, even though the white matter alterations of PSP resemble those of corticobasal degeneration, there are certain ultrastructural differences in the abnormal oligodendroglial tubules of the two diseases. Received: 4 October 1996 / Accepted: 6 December 1996  相似文献   
6.
Non-progressive juvenile spinal muscular atrophy of the distal upper limb (Hirayama's disease) occurs predominantly in men in the second decade with unilateral weakness of the fingers and hand, and atrophy of the hand and forearm. The symptoms generally progress for 3-4 years after onset and then stop. Since the second decade is a very important period starting one's career, early stopping of the progression and possibly the improvement are essential. On the bases of the neuroradiological studies, a forward displacement of the posterior wall of the dural canal at the lower cervical level on neck flexion is presumed to be the main pathogenetic mechanism in this disease. On neck flexion, the spinal cord is compressed anteroposteriorly at C7 and C8 segmental levels. Pathological studies suggested that chronic microcirculatory disturbances in the spinal cord as the result of repeated flexion of the neck might produce necrosis of the anterior horns. We used a cervical collar for the prevention of neck flexion in 14 patients in the early stage and compared the results with those of 18 patients who had natural courses. In the therapy group, muscle weakness of the affected hand improved in 5 patients and the progression of the disease was stopped in 8 patients with the duration of 1.8 +/- 1.2 years, whereas the duration of progression of the natural course group was 2.9 +/- 1.6 years. Only one patient who could not tolerate the use of collar showed a slight progression. These results suggest that the cervical collar is a useful therapeutic tool in this disease.  相似文献   
7.
We describe a 54-year-old woman with primary pulmonary adenocarcinoma showing a characteristic papillary architecture and prominent cilia formation. Immunohistochemically, the tumor cells were positive for carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA) and Leu Ml, and negative for lactoferrin and surfactant apoprotein. An ultrastructural study also indicated differentiation toward bronchial surface epithelial cells. To our knowledge, this type of neoplasm has not been reported as peripheral-type adenocarcinoma of the lung. Acta Pathol Jpn 42: 745–750, 1992.  相似文献   
8.
A case of hepatic infarction with portal thrombosis is reported. A 63-year-old woman with liver cirrhosis and esophageal varices was admitted for treatment of the esophagel varices. Endoscopic variceal ligation (EVL) and endoscopic injection sclerotherapy (EIS) were performed. Two months later, she experienced right hypochondralgia and right flank pain. Serum transaminase levels were suddenly elevated, and computed tomography scans of the liver showed multiple small nodular lesions. Her condition worsened, and she died of hepatic failure. Autopsy revealed splenic and portal vein thrombosis, multiple hepatic infarction, and evidence of chronic pancreatitis. We believe that liver cirrhosis and chronic pancreatitis were the main risk factors for the portal thrombosis, and the treatment for esophageal varices appeared to have triggered the thrombosis. The hepatic infarction was caused by the portal thrombosis.  相似文献   
9.
Clinicopathologlc and mucin histochemical characteristics of 90 cases of ovarian mucinous borderline tumors (MBT) of Intestinal (IMET) and müllerian types (MMBT) were studied to determine whether IMBT and MMBT constitute distinct tumor subtypes. The IMBT (77 cases, 78 lesions) contained goblet cells, absorptive cells and endocrine cells, which represented Intestinal differentiation. The average diameter of IMBT was 13.4 cm. Five patients (6.5%) had stage III disease wtth pseudomyxoma perltonel and one of them died from tumor. Approximately 50% of IMBT demonstrated gastrointestinal characteistics on mucin histochemistry. The MMBT (13 cases, 14 lesions) consisted of mumus columnar cells and eosinophilic cells, with no Intestinal differentiation. MMBT accounted for 15.2% of MBT. MMBT averaged 8.4 cm in diameter, and 29% were associated with endometriosls of the ipsilateral ovary. All patients with MMBT had stage I disease, and none suffered from pseudomyxoma peritonel. All patients whose follow-up data were available were alive and well, without evidence of tumor recurrence. The mucin histochemical findings in MMBT resembled those of noml endocervix. Results of the present study suggest that IMBT and MMBT have different characteristics and constitute distinct subtypes of MBT.  相似文献   
10.
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