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   32893篇
  免费   1632篇
  国内免费   152篇
耳鼻咽喉   415篇
儿科学   581篇
妇产科学   580篇
基础医学   4398篇
口腔科学   1180篇
临床医学   2607篇
内科学   7738篇
皮肤病学   799篇
神经病学   2430篇
特种医学   1309篇
外科学   5432篇
综合类   221篇
一般理论   2篇
预防医学   1052篇
眼科学   511篇
药学   2220篇
中国医学   46篇
肿瘤学   3156篇
  2022年   276篇
  2021年   607篇
  2020年   284篇
  2019年   432篇
  2018年   602篇
  2017年   431篇
  2016年   477篇
  2015年   573篇
  2014年   755篇
  2013年   835篇
  2012年   1313篇
  2011年   1426篇
  2010年   781篇
  2009年   725篇
  2008年   1276篇
  2007年   1352篇
  2006年   1382篇
  2005年   1419篇
  2004年   1381篇
  2003年   1324篇
  2002年   1338篇
  2001年   1239篇
  2000年   1402篇
  1999年   1223篇
  1998年   401篇
  1997年   288篇
  1996年   302篇
  1995年   279篇
  1994年   248篇
  1993年   235篇
  1992年   818篇
  1991年   774篇
  1990年   692篇
  1989年   707篇
  1988年   697篇
  1987年   679篇
  1986年   684篇
  1985年   605篇
  1984年   438篇
  1983年   357篇
  1979年   345篇
  1978年   235篇
  1977年   205篇
  1975年   198篇
  1974年   236篇
  1973年   218篇
  1972年   200篇
  1971年   215篇
  1970年   205篇
  1969年   229篇
排序方式: 共有10000条查询结果,搜索用时 734 毫秒
41.
42.
HTLV-I seroprevalence in patients with malignancy   总被引:5,自引:0,他引:5  
Since many malignancies often occur in patients with smoldering type adult T-cell leukemia (ATL) (5 of 18 cases in this report), the relationship between HTLV-I (human T-cell leukemia virus type I) infection, which is closely associated with ATL, with other malignancies in an HTLV-I endemic area was examined. Among the 394 patients with malignancies and who had not had blood cell transfusions, 61 (15.5%) tested positive for HTLV-I antibody. The prevalence was significantly higher in males older than age 40 years and females of all ages compared to age- and sex-matched healthy individuals. The overall seroprevalence (26.1%) in 291 patients with malignancies and who had had blood cell transfusions was higher than that of those who had not had blood transfusions. There was no significant correlation between the site of malignancy and antibody prevalence. These results suggest the possibility that development of malignancy may contribute to expression of latent HTLV-I infection and that HTLV-I infection may contribute to the risk of other malignancies.  相似文献   
43.
Intralobar pulmonary sequestration associated with asymptomatic aspergillosis is a rare case. We describe the case of a 65-year-old woman with intrapulmonary sequestration, anomalous systemic arterial supply to the left lower lobe and aspergillosis who underwent left lower lobectomy and ligation of an anomalous artery by Video-Assisted Thoracoscopic surgery (VATS). Pathological examination showed the parenchymal distortion and chronic inflammation. Aspergillus were found in the cyst. VATS lobectomy for intralobar pulmonary sequestration is a safe and valid procedure.  相似文献   
44.
A 65-year-old woman with diabetes mellitus and chronic otitis media developed headache, fever, and hoarseness, all of which did not responded to the oral antibiotics. As stiff neck and lower cranial nerve palsies appeared, bacterial meningitis was suspected. Neurological examination revealed the right hearing disturbance, right recurrent laryngeal nerve palsy, left sternocleidomastoid muscle atrophy and bilateral tongue atrophy. The CSF examination revealed mild pleocytosis and elevated protein, but no bacterial organism was cultured from the CSF. CT scans showed bilateral mastoiditis, and the right mastoid process and a posterior part of the petrous bone were eroded, indicating the exposed bony structures to the posterior fossa. MRI scans demonstrated the thickening of the dura mater of the posterior fossa and the right cerebellar tentorium. This is a rare example of bacterial pachymeningitis of the posterior fossa, the clinical symptoms and MRI findings of which resolved solely by antimicrobial agents without corticosteroid.  相似文献   
45.
46.
A case of generalized eruptive histiocytoma (GEH) was evaluated and examined histopathologically and ultrastructurally. A 24-year-old male had an episode of high fever and drug-induced eruption prior to the appearance of multiple skin lesions. Uniform, red to dark-red papular lesions appeared on his cheeks and then became generalized. The lesions were composed of a massive dermal infiltrate of histiocytes, which had oval nuclei and amphophilic cytoplasm. The cytoplasm contained unique annular structures, myeloid bodies and vacuoles. The specificity of these structures is as yet unknown. Reactive stimulation rather than neoplastic proliferation may be a causative factor in GEH.  相似文献   
47.
The findings in twenty-two patients with insulinoma were reviewed, as continuous efforts should be made to establish preoperative localization of the tumor. Superselective arteriography and percutaneous, transhepatic portal vein and pancreatic venous catheterization are highly recommended approaches. At the time of surgical intervention, a cautious exploration of the pancreas after thorough mobilization is most important. Recent use of intraoperative ultrasonography increases the likelihood of finding these occult tumors which locate deeply in the head of the pancreas. Apart from the diagnostic problems, we wish to emphasize the high incidence of malignancy (7/22, 31.8 per cent) in our series. Althout patients with malignant isulinoma had a much better prognosis compared to those with a pancreatic ductal malignancy, pancreatic resection with regional lymphnode dissection seems to be a rational procedure. Enucleation can be done when intraoperative findings of the tumor and regional lymphonode indicate no malignant features and no multiple lesions. However, at the first operation, enucleation is still a procedure of choice, even for the malignant insulinoma in the head with a well-defined capsule and no metastatic lesions, the objective being to avoid a duodenopancreatectomy or total pancreatectomy. These data were reported at the 30th Congress of Société Internationale de Chirurgie, Hamburg, Germany, 1983  相似文献   
48.
Idiopathic membranous nephropathy in two brothers   总被引:1,自引:0,他引:1  
Idiopathic membranous nephropathy has been reported rarely to develop in genetic association with certain HLA antigens. This paper describes two male siblings presenting with nephrotic syndrome with histologically proven membranous nephropathy. The younger brother maintained a normal renal function with slight proteinuria during the 3 years of follow-up, but the older one experienced a rapid decline in renal function and had to be put on maintenance hemodialysis. No clinical evidence of contributory underlying disease such as malignancy or systemic lupus erythematosus could be found. HLA typing was carried out in the two patients and in members of their family. Several HLA antigens were found to be shared by the two patients. However, the HLA antigens which have been reported to be associated with idiopathic membranous nephropathy were not found in either of them.  相似文献   
49.
Summary The histogenesis of stromal cells in capillary hemangioblastoma has been the subject of debate. The light and electron microscopic studies of hemangioblastomas presented here showed pericytic and leiomyoblastic features in stromal cells. Cells cultured by the monolayer method showed similar features to those of the original tumors. Immunohistochemical studies for glial fibrillary acidic protein and factor VIII/von Willebrand factor indicated that stromal cells were antigenically distinct from astrocytes and endothelial cells. These findings suggest that stromal cells are closely related to pericytes and smooth muscle cells, and support Rhodin's speculation that pericytes serve as a precursor to smooth muscle cells.  相似文献   
50.
The byproducts P-1 and P-2, which were produced during the synthesis of porcine secretin, were isolated in pure form from the crude secretin by HPLC. These were identified by a combination of amino acid analysis, enzymatic digestion, and isocratic or linear gradient reversed-phase (RP)-HPLC. The amino acid compositions of P1 and P2, determined by amino acid analysis after acid hydrolysis, were found to be the same as those of porcine secretin without distinction between L-and D-amino acids. But, HPLC of their digestive fragments with trypsin and alpha-chymotrypsin differed from that of secretin. The fragments, S7-12 of P-1 and S13-21 of P-2 were determined to be different from the corresponding fragments obtained from secretin by HPLC analysis of their digestive fragments. The amino acid composition of each acid hydrolysate, following digestion with D-amino acid oxidase, was found to have less leucine or alanine content than secretin. The HPLC analysis of the fragments from P-1 and P-2 by tryptic and alpha-chymotryptic digestion showed that they are the same as those from synthetic D-Leu10 secretin or D-Ala17 secretin, respectively. Consequently, P-1 and P-2 are concluded to be the secretin diastereoisomers, D-Leu10 and D-Ala17 secretin, respectively.  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