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   14004篇
  免费   699篇
  国内免费   49篇
耳鼻咽喉   223篇
儿科学   265篇
妇产科学   140篇
基础医学   1688篇
口腔科学   407篇
临床医学   823篇
内科学   3636篇
皮肤病学   471篇
神经病学   892篇
特种医学   594篇
外科学   2581篇
综合类   45篇
一般理论   3篇
预防医学   380篇
眼科学   131篇
药学   827篇
中国医学   13篇
肿瘤学   1633篇
  2023年   64篇
  2022年   120篇
  2021年   252篇
  2020年   152篇
  2019年   208篇
  2018年   226篇
  2017年   181篇
  2016年   206篇
  2015年   208篇
  2014年   277篇
  2013年   348篇
  2012年   601篇
  2011年   627篇
  2010年   352篇
  2009年   336篇
  2008年   602篇
  2007年   656篇
  2006年   624篇
  2005年   653篇
  2004年   592篇
  2003年   627篇
  2002年   557篇
  2001年   566篇
  2000年   551篇
  1999年   485篇
  1998年   156篇
  1997年   157篇
  1996年   141篇
  1995年   111篇
  1994年   107篇
  1993年   93篇
  1992年   359篇
  1991年   331篇
  1990年   308篇
  1989年   321篇
  1988年   289篇
  1987年   301篇
  1986年   268篇
  1985年   291篇
  1984年   174篇
  1983年   156篇
  1982年   75篇
  1981年   64篇
  1979年   135篇
  1978年   68篇
  1975年   63篇
  1974年   72篇
  1973年   83篇
  1972年   62篇
  1971年   58篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
目的 为了减轻免疫诱导过程中对受体的侵袭 ,进一步探讨以家兔为动物模型 ,通过异体骨髓移植诱导同种皮肤移植免疫耐受。方法 通过骨髓腔内直接注射异体骨髓细胞 ,进行骨髓移植。结果 皮片的平均存活时间是 (88.0± 6 .0 )天 (P <0 .0 0 1 )。为了探讨其普遍性 ,我们用此诱导方法 ,还进行了同种全耳移植。平均存活时间是 (1 4 6 .0± 1 5 .1 )天 ,并有 1只移植耳存活时间已超过 1年 ,未见任何排斥反应。结论 本研究证明了以家兔为动物模型 ,在不使用免疫抑制剂的情况下 ,通过骨髓腔内直接注射异体骨髓细胞 ,进行骨髓移植的方法 ,不仅在皮肤移植上可以诱导长期稳定的特异性免疫耐受 ,而且在实质性器官耳的同种移植上取得了良好的效果  相似文献   
32.
Uterus didelphys with unilateral imperforate vagina is rare. Interestingly, in all reported cases in which the urinary tract was investigated renal agenesis was found on the side of the obstructed hemivagina. We report 2 cases of this unusual and interesting condition, and review the embryogenesis of müllerian duct abnormalities associated with renal agenesis, as well as the clinical findings, diagnosis and management. We stress the importance of prompt and accurate diagnosis, and treatment as a means to avoid unnecessary surgical procedures.  相似文献   
33.
34.
Intact K562 human leukemic cells showed bright membrane immunofluorescence after staining with monoclonal antibody to O-phosphotyrosine (PTyr). Up to 60% of the cells were lysed with mouse, rabbit, or human antibodies to PTyr by a complement-mediated mechanism. A new method has been developed for identifying proteins that have PTyr residues on the outside of cell membrane, and at least two species of PTyr-containing proteins with the molecular weights of 45,000 and 36,000 were identified as the most probable candidates of the antigens responsible for the membrane fluorescence and cell lysis.  相似文献   
35.
New inferior vena caval filters for percutaneous placement were made by attaching filter wires similar to those in the bird's nest inferior vena caval filter onto expandable metallic stents. These stents formed a base on which to anchor the filter to the wall of the inferior vena cava. The stent filter can be introduced through a 12- to 13-French catheter sheath system. The system was successfully tested in 13 dogs.  相似文献   
36.
Insulin and the insulin-like growth factors IGF-I and IGF-II are thought to exert their mitogenic effects in cultured chick embryo fibroblasts and human skin fibroblasts via IGF receptors rather than via insulin receptors. These effects appear to be mediated by the type I subtype of IGF receptor, which is structurally similar to the insulin receptor and exhibits significant cross-reactivity with insulin. As a first step in our long-range goal of defining those features of the IGF-I and IGF-II molecules that confer enhanced mitogenic activity and reactivity with these mitogenic type I IGF receptors, we have prepared two hybrid insulin-IGF molecules and examined their mitogenic and binding activities: (1) A27-insulin, containing an elongated 27-residue A-chain (in which the 6-residue D-domain of IGF-II was added to the carboxy-terminus of the 21-residue A-chain of insulin) combined with the B-chain of insulin; and (2) A insulin-B IGF-1, containing the A-chain of insulin and the synthetic 30-residue B-domain of IGF-I. Both hybrid molecules stimulated DNA synthesis and inhibited 125I-IGF-I binding to type I IGF receptors in both chick embryo and human fibroblast cultures. A27-insulin had considerably greater mitogenic potency and binding potency than A insulin-B IGF-I. Neither hybrid molecule was more potent in these assays than insulin, indicating that the presence of D IGF-II or B IGF-I by itself was not sufficient to increase the mitogenic potency of insulin in fibroblasts. By contrast, A insulin-B IGF-I showed enhanced reactivity with an antiserum to IGF-I. A27-insulin retained significant insulin-like metabolic activity despite the presence of the D-domain of IGF-II.  相似文献   
37.
38.
39.
There have been only 2 previous reports of nonimmunologic hydrops fetalis (NIHF) caused by fetal Kasabach-Merritt syndrome, both of which were pathological studies. This is the first clinical case report of NIHF due to fetal Kasabach-Merritt syndrome that was prenatally diagnosed by sonography, computerized tomography, and percutaneous umbilical blood sampling.  相似文献   
40.
Tuberculous aneurysms of the aorta need early diagnosis and prompt surgical intervention because if untreated, they lead to severe consequences. We report herein, a case of a 63 year old woman who underwent successful resection of a tuberculous pseudoaneurysm which had ruptured into the left upper lobe of the lung after a punch biopsy, performed under bronchoscopy, had caused severe bleeding. Subsequent CT and MRI examinations suggested a fistula between the mass and the aorta and proved useful in establishing the diagnosis of a pseudoaneurysm. We wish to emphasize the need for bronchoscopy to be done carefully because of the risk of inducing massive hemoptysis.  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