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   1259篇
  免费   72篇
  国内免费   21篇
耳鼻咽喉   45篇
儿科学   114篇
妇产科学   11篇
基础医学   109篇
口腔科学   50篇
临床医学   115篇
内科学   290篇
皮肤病学   30篇
神经病学   18篇
特种医学   265篇
外科学   81篇
综合类   18篇
预防医学   49篇
眼科学   12篇
药学   66篇
中国医学   1篇
肿瘤学   78篇
  2024年   3篇
  2023年   4篇
  2022年   3篇
  2021年   13篇
  2020年   8篇
  2019年   11篇
  2018年   15篇
  2017年   15篇
  2016年   20篇
  2015年   28篇
  2014年   23篇
  2013年   43篇
  2012年   6篇
  2011年   12篇
  2010年   37篇
  2009年   65篇
  2008年   26篇
  2007年   40篇
  2006年   40篇
  2005年   34篇
  2004年   26篇
  2003年   23篇
  2002年   16篇
  2001年   15篇
  2000年   22篇
  1999年   27篇
  1998年   81篇
  1997年   93篇
  1996年   84篇
  1995年   65篇
  1994年   63篇
  1993年   79篇
  1992年   16篇
  1991年   13篇
  1990年   16篇
  1989年   38篇
  1988年   28篇
  1987年   20篇
  1986年   27篇
  1985年   25篇
  1984年   14篇
  1983年   11篇
  1982年   12篇
  1981年   27篇
  1980年   17篇
  1979年   6篇
  1978年   8篇
  1977年   15篇
  1976年   13篇
  1975年   5篇
排序方式: 共有1352条查询结果,搜索用时 15 毫秒
101.
Morrison  MC; Lee  MJ; Stafford  SA; Saini  S; Mueller  PR 《Radiology》1990,176(2):574-576
The authors present two cases of percutaneous cecostomy performed with a modified approach previously described for percutaneous gastrostomy and cholecystostomy. T-fastener devices were used to affix the cecum to the anterior abdominal wall; thus, the potential problem of fecal spillage was prevented. In both cases, adequate fecal drainage was provided without complication.  相似文献   
102.
We describe three patients who had typical features of hairy cell leukemia (HCL) and multiple myeloma (MM) at the same time. In two, both diagnoses were made within a short period of time, and in the third, HCL had been present for 2 yr before the appearance of a paraprotein, bone lesions, and plasma-cell infiltrates established the diagnosis of MM. Although this association has not been previously reported, cases of HCL with osteolytic lesions or a paraprotein band have been described. The cases described may represent clinical manifestations of closely related disorders arising from divergent differentiation from a common B-cell precursor rather than a chance association.  相似文献   
103.
Petzer  AL; Eaves  CJ; Lansdorp  PM; Ponchio  L; Barnett  MJ; Eaves  AC 《Blood》1996,88(6):2162-2171
Elevated numbers of primitive Philadelphia chromosome-positive (Ph+) progenitors, including long-term culture-initiating cells (LTC-IC) as well as colony-forming cells (CFC), have been previously described in the blood of patients with chronic myeloid leukemia (CML) in chronic phase with high white blood cell counts. In the present study, which focused primarily on an analysis of circulating progenitors present in such patients at diagnosis, we discovered the frequent and occasionally exclusive presence of circulating normal (Ph-) LTC-IC, often at levels above those seen for LTC-IC in the blood of normal individuals. The presence of detectable numbers of circulating Ph- LTC-IC was independent of the fact that the same peripheral blood samples also contained elevated numbers of predominantly or exclusively Ph+ CFC. Interestingly, both the Ph+ and Ph- LTC-IC in these samples were CD34+CD71- and variably CD38- and Thy-1+, as previously documented for LTC-IC in normal marrow. Thus, neither CD38 nor Thy-1 expression was useful for discriminating between Ph+ and Ph- LTC-IC in mixed populations. Nevertheless, an association of these phenotypes with LTC- IC function did allow highly enriched (> 5% pure) suspensions of either Ph+ or Ph- LTC-IC to be obtained from selected samples of CML blood in which the initial LTC-IC population was either predominantly Ph+ or Ph- , respectively. These findings suggest that the mechanisms causing mobilization of leukemic stem cells in untreated CML patients may affect their normal counterparts. They also indicate a possible new source of autologous cells for the support of intensive therapy of CML patients. Finally, they provide a method for obtaining the most highly purified populations of Ph+ LTC-IC described to date. This method should be useful for further analyses of the molecular activities of these very primitive neoplastic cells.  相似文献   
104.
目的 与开腹胆囊切除术相比,腹腔镜胆囊切除术(LC)有减少术后不适和较少的创作,但仍有改进的余地。方法:为进一步减轻手术创伤,我们引进了针式腹间胆囊切除术,共29例。结果 平均手术时间为75分钟,19例当天出院,10例隔天出院,其中1例是胆总管探查。结论 针式航空 镜胆囊切除术是一种可靠的技术。  相似文献   
105.
A protein S deficient family presenting a variant protein S molecule in plasma and platelets is described. The propositus, age 20, and two brothers suffered from venous thrombotic disease. The propositus, the only family member studied while taking oral anticoagulants, had a protein S antigen (ag) level of 17% and undetectable activity. As demonstrated by immunoblotting both the propositus and one clinically affected brother (42% ag, 7% activity) presented variant protein S molecules of 65,000 molecular weight (mol wt) while the other clinically affected brother (64% ag, 11% activity) had only protein S with normal electrophoretic mobility of 70,000 mol wt. The mother had normal protein S levels (93% ag, 100% activity) but had both normal and variant protein S molecules and based on her functional protein S data a normal anticoagulant activity of the variant molecule is suggested. One asymptomatic but protein S deficient sister (68% ag, 9% activity) as well as the asymptomatic protein S deficient father (59% ag, 10% activity) had only protein S molecules of 70,000 mol wt. The variant protein S bound to C4b-binding protein in plasma, and differed from normal protein S in carbohydrate content. Platelets of each family member contained the same immunoblotting pattern of normal and variant protein S forms as found in plasma, consistent with the hypothesis that protein S gene expression involves codominant expression of two alleles that is similar in cells that control the synthesis of both platelet and plasma forms of protein S.  相似文献   
106.
107.
108.
Gastrointestinal teratomas are uncommon, benign neoplasms that occur primarily in children. A retrospective review of five cases (two gastric, one pancreatic, one mesenteric, and one in the lesser omentum) is presented with emphasis on the computed tomographic and ultrasonographic appearances. Principal findings are a well-defined mass with separate cystic and solid components of varying proportions, discrete areas with densities similar to that of fat, or coarse, globular calcifications within the solid component. Recognition of these findings may allow the radiologist to make a correct preoperative diagnosis of teratoma.  相似文献   
109.
Cerebrospinal fluid rhinorrhea: depiction with MR cisternography in dogs   总被引:2,自引:0,他引:2  
Canine cerebrospinal fluid rhinorrhea, which occurs frequently in purebred beagles, was demonstrated in two dogs on magnetic resonance images after cisternal introduction of gadolinium-DTPA dimeglumine.  相似文献   
110.
Atrial-level shunts: sensitivity and specificity of MR in diagnosis   总被引:4,自引:0,他引:4  
  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