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   27119篇
  免费   2101篇
  国内免费   1413篇
耳鼻咽喉   280篇
儿科学   292篇
妇产科学   377篇
基础医学   3172篇
口腔科学   590篇
临床医学   2918篇
内科学   5627篇
皮肤病学   248篇
神经病学   1340篇
特种医学   948篇
外国民族医学   11篇
外科学   3451篇
综合类   3178篇
一般理论   2篇
预防医学   1266篇
眼科学   643篇
药学   2557篇
  15篇
中国医学   965篇
肿瘤学   2753篇
  2024年   50篇
  2023年   318篇
  2022年   667篇
  2021年   1067篇
  2020年   728篇
  2019年   714篇
  2018年   828篇
  2017年   666篇
  2016年   734篇
  2015年   999篇
  2014年   1215篇
  2013年   1042篇
  2012年   1714篇
  2011年   1846篇
  2010年   1087篇
  2009年   889篇
  2008年   1427篇
  2007年   1354篇
  2006年   1338篇
  2005年   1317篇
  2004年   995篇
  2003年   958篇
  2002年   898篇
  2001年   764篇
  2000年   837篇
  1999年   775篇
  1998年   454篇
  1997年   378篇
  1996年   355篇
  1995年   343篇
  1994年   247篇
  1993年   223篇
  1992年   428篇
  1991年   386篇
  1990年   309篇
  1989年   292篇
  1988年   281篇
  1987年   267篇
  1986年   244篇
  1985年   203篇
  1984年   138篇
  1983年   101篇
  1982年   61篇
  1981年   68篇
  1979年   67篇
  1978年   58篇
  1977年   43篇
  1975年   50篇
  1974年   52篇
  1969年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Polycythemia vera (PV) is a clonal disease of the hematopoietic stem cell characterized by a hyperplasia of marrow erythropoiesis, granulocytopoiesis, and megakaryocytopoiesis. We previously reported that highly purified PV blood burst-forming units-erythroid (BFU-E) are hypersensitive to recombinant human interleukin-3 (rIL-3). Because these cells may be only a subset, and not representative of marrow progenitors, we have now studied partially purified marrow hematopoietic progenitor cells. Dose-response experiments with PV marrow BFU-E showed a 38-fold increase in sensitivity to rIL-3 and a 4.3-fold increase in sensitivity to recombinant human erythropoietin (rEpo) compared with normal marrow BFU-E. In addition, PV marrow colony-forming units-granulocyte-macrophage (CFU-GM) and CFU-megakaryocyte (CFU-MK) also showed a marked hypersensitivity to rIL-3 and to human recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF). Dose-response curves with rGM-CSF and blood BFU-E showed a 48-fold increase in sensitivity. No effect of rIL-4, rIL-6, human recombinant granulocyte-CSF (rG-CSF), or macrophage-CSF (rM-CSF) was evident, nor was there any effect of PV cell-conditioned medium on normal BFU-E, when compared with normal cell-conditioned medium. Autoradiography with 125I-rEpo showed an increase in Epo receptors after maturation of PV BFU-E to CFU-E similar to that shown with normal BFU-E, but no increase of specific binding of 125I-rIL-3 by PV CD34+ cells was seen compared with normal CD34+ cells. These studies show that PV marrow hematopoietic progenitor cells are hypersensitive to rIL-3 and rGM-CSF, similar to PV blood BFU-E. While the mechanism does not appear to be due to enhanced binding of rIL-3, the hypersensitivity of PV progenitor cells to IL-3 and GM-CSF may be a key factor in the pathogenesis of PV.  相似文献   
92.
豚鼠中耳(听泡)内滴入0.5%、1%、2%环丙沙星与庆大霉素滴耳液7天或21天,借助光镜和扫描电镜观察内耳的显微和超微结构变化。结果证明环丙沙星对内耳没有明显的毒性作用。庆大霉素则使耳蜗明显受损,以底回为重,Corti’s器外毛细胞坏死较多,内毛细胞及支持细胞病变较轻。位觉斑耳石脱落,毛细胞纤毛粘连、脱落。壶腹嵴中央区纤毛也缺失。本实验对客观评价环丙沙星对内耳的作用及临床使用提供了形态学资料。  相似文献   
93.
The Raz four-corner suspension for the treatment of severe (grades 3 and 4) cystocele has yielded poor results, and is the subject of this paper. During a 10-month period from June 1988 to April 1989, 27 patients with severe cystocele and genuine stress incontinence were treated by the Raz four-corner suspension. Each patient had full preoperative urodynamic evaluation. Twenty-two patients were available for follow-up examinations at 3.5–4 years. At the 6-week postoperative examination all patients had excellent support of the anterior vaginal wall, including the restoration of the anterolateral vaginal wall sulci. However, within 10 months, 6 patients had recurrence of cystoceles of grade 2 or more. These results led to the abandonment of this procedure. On long-term follow-up examination at 3.5–4 years, 59% (13/22) of the patients had recurrence of cystoceles of grade 2 or more. The possible causes for these poor results are discussed. At present therefore, the Raz four-corner suspension for severe cystoceles is not recommended.  相似文献   
94.
A 14-year-old girl was admitted because of cough, chest pain and hemosputum. Chest roentgenogram on admission showed a pneumothorax and a cavitary lesion with niveau formation in the right lung and cystic lesions in the bilateral lung fields. After bed rest and intravenous administration of antibiotics for two weeks, the right lung inflated well and the niveau formation disappeared, and the patient was discharged. One week later, she was readmitted with sudden-onset severe dyspnea, caused by bilateral pneumothoraces. Emergency tube thoracostomy and wedge resection of the bullous lesion was performed. Macroscopically, multiple small cystic changes were seen on the surface of the right lung. Histological examination revealed nodular proliferations of smooth muscle cells in the interstitium and vessel walls in the lung, which contained slit-like lymphatic channels. The diagnosis of pulmonary lymphangiomyomatosis was made. In this case, we could not measure receptors for estrogen and progesterone. Recently, hormonal therapy and oophorectomy have been reported as being useful. Tamoxifen (Norvadex) was therefore initiated, and the patient has remained well with slight dyspnea on exertion. There has been no recurrence of pneumothorax. Lymphangiomyomatosis is a rare disease of unknown etiology which occurs exclusively in women, mostly in those of reproductive age. We report a 14-year-old female patient with lymphangiomyomatosis associated with repeated pneumothorax, who had been under treatment for epilepsy. We believe this case to be of importance because of the long discussed relation between pulmonary lymphangiomyomatosis and tuberous sclerosis.  相似文献   
95.
96.
Thrombocytopenia is a frequent finding following living donor hepatectomy. It appears more pronounced in right graft donors than in left graft donors. This study analyzed postoperative thrombocytopenia in 20 living liver donors and examined the change of endogenous thrombopoietin (TPO) in its recovery. Platelet count, TPO level, fibrinogen degradation product (FDP), and D-Dimer were measured before surgery and on postoperative days (PODs) 1, 2, 3, 5, 7, and 14. Concurrently, liver and spleen volumes were calculated by computed tomography. Platelet count on POD 3 was significantly lower in right graft donors than in left graft donors (13.0 +/- 3.7 x 10(4)/microL vs. 16.8 +/- 4.0 x 10(4)/microL, P = 0.039) but recovered by POD 7 in all donors. Postoperative elevations of FDP and D-Dimer were significantly higher in right graft donors than in left graft donors. TPO level rose immediately after surgery, peaked on POD 5 in left graft donors and on POD 7 in right graft donors, and fell nearly to preoperative levels by POD 14. Postoperative TPO level per liver volume was significantly higher in right graft donors than in left graft donors. In conclusion, thrombocytopenia following living donor hepatectomy resolved within the first week regardless of graft type and was mainly associated with increasing consumption of circulating platelets, possibly due to intrahepatic and splenic congestion. With a reduced number of circulating platelets, TPO level rapidly increases. Also, with reduced consumption of platelets related to recovery from surgery, thrombocytopenia should resolve. As a consequence, TPO level would be expected to fall.  相似文献   
97.
在心脏手术中应用多普勒彩色超声心动仪直接探测和观察19例患者,其中风湿性心瓣膜病11例、先天性心脏病7例、左心房粘液瘤1例。风心病及左房粘液瘤患者手术前、中检查的结果基本一致;先心病术前诊断符合率为84.2%(5/7),术中诊断符合率为100%。本文对检查结果作了分析讨论,并提出符合我国情况的有关检查设想。  相似文献   
98.
研究了77例长沙地区孕、产妇的宫颈排毒(CMV)情况及母、婴的免疫状态,并对宫颈排毒及CMV一IgM阳性的母亲所生小孩进行临床追踪。结果显示:孕妇宫颈排毒率为4.5%,抗CMV-IgG和抗CMV-IgM阳性率分别为77%和13%,59例脐血CMV-IgM阴性。宫颈排毒的3例其抗体检测抗CMV-IgG均阳性,抗CMV-IgM仅一例阳性。作者认为,对妊娠期活动性CMV感染的诊断,仅检测抗CMV-IgG和抗CMV-IgM抗体滴度仍不足,尚须结合病毒分离和其它检测手段。  相似文献   
99.
The surgical management in papillary thyroid cancer has been highly controversial. In the Department of Surgery (II), Kanazawa University Hospital, the surgical management especially for cervical lymph node metastases has changed since 1973 from a conservative approach to an aggressive one. In order to determine whether an aggressive approach is warranted, a retrospective multivariate analysis was carried out on 106 cases of papillary thyroid cancer. The patients have been followed for 10-28 years. Multivariate analysis was conducted following Cox's model. By this analysis, aggressive management appeared to have no impact on survival or relapse-free survival. However, age, sex, tumor size, and cervical lymphadenopathy were confirmed to be important prognostic factors in survival and/or relapse-free survival.  相似文献   
100.
A Ikoma  N Nakamura  T Miyazaki  M Maeda 《Surgery》1992,111(5):595-600
We report a 64-year-old woman with double cancer of the gallbladder and the common bile duct associated with anomalous junction of the pancreaticobiliary ductal system. Eleven previous cases have been reported to date. From analysis of the 12 cases reviewed, including our patient, double cancer of the gallbladder and the common bile duct accompanied by anomalous junction of the pancreaticobiliary ductal system is characterized by the predominance of well-differentiated and superficial cancer.  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