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   23944篇
  免费   1792篇
  国内免费   143篇
耳鼻咽喉   210篇
儿科学   937篇
妇产科学   659篇
基础医学   3190篇
口腔科学   380篇
临床医学   2520篇
内科学   4924篇
皮肤病学   515篇
神经病学   2655篇
特种医学   578篇
外科学   2128篇
综合类   156篇
一般理论   37篇
预防医学   3103篇
眼科学   311篇
药学   1486篇
  1篇
中国医学   39篇
肿瘤学   2050篇
  2024年   32篇
  2023年   383篇
  2022年   695篇
  2021年   1207篇
  2020年   758篇
  2019年   1001篇
  2018年   1075篇
  2017年   811篇
  2016年   882篇
  2015年   922篇
  2014年   1208篇
  2013年   1455篇
  2012年   2149篇
  2011年   2168篇
  2010年   1122篇
  2009年   948篇
  2008年   1398篇
  2007年   1329篇
  2006年   1230篇
  2005年   1076篇
  2004年   916篇
  2003年   789篇
  2002年   686篇
  2001年   133篇
  2000年   95篇
  1999年   105篇
  1998年   113篇
  1997年   106篇
  1996年   77篇
  1995年   83篇
  1994年   54篇
  1993年   60篇
  1992年   53篇
  1991年   60篇
  1990年   46篇
  1989年   42篇
  1988年   52篇
  1987年   39篇
  1986年   47篇
  1985年   29篇
  1984年   44篇
  1983年   27篇
  1982年   35篇
  1981年   35篇
  1980年   29篇
  1979年   20篇
  1978年   26篇
  1975年   18篇
  1974年   21篇
  1973年   27篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
We report on a 26-year-old female affected by Noonan syndrome (NS), a congenital disorder characterized by various phenotypic features and congenital anomalies) associated with a variety of autoimmune diseases, including systemic lupus erythematosus, celiac disease, and Hashimoto thyroiditis. Autoimmunity is seldom described in NS and the association between this congenital disease and three autoimmune disorders has not been previously reported. Should the occurrence of autoimmune disorders in NS be confirmed, a relevant clinical and laboratory evaluation of NS patients should be performed in order to clarify whether the immune system involvement represents only an occasional event or is a feature of the disease.  相似文献   
54.
A universal method for selection of surface marker-positive cells is described. The cells, admixed with an excess of surface marker-negative cells, are In-st labelled with a specific biotinylated ligand and then isolated with the aid of monoclonal, anti-biotin coated beads. The method enables selection and isolation of cells with a frequency as low as 10-4. The ligand can be an antigen (for selection of infrequent antibody-producing cells), an antibody (for selection of surface antigen-positive cells) or other molecules (for selection of specific receptor-positive cells).  相似文献   
55.
Total extrusion of the talus without recovery of the bone is a very unusual injury. The authors present a case of a 25-year-old man who sustained an open total enucleation of the talus in a motorcycle accident. The talus was not recovered at the scene of the accident. An immediate tibiocalcaneal stabilization was performed by using an external fixator. In the postoperative period, a polymicrobic infection was observed and treated with parenteral antibiotics. Nine months after injury, the patient developed an infection of both the empty space and the distal third of the tibia. A wound debridement with tibial sequestrectomy and insertion of gentamicin-impregnated polymethylmethacrylate beads was performed. Three months later, after multiple negative bacteriologic examinations, a tibiocalcaneal arthrodesis with staples and autogenous bone graft was performed. Because of a pseudoarthrosis, the patient underwent a revision of the arthrodesis by retrograde tibiocalcaneal nailing, achieving clinical and radiographic success. The definitive treatment of total enucleation of the talus is still controversial because of its rarity and the high rate of complications, such as avascular necrosis, osteomyelitis, and ankle stiffness. In this case, without recovery of the talus, retrograde nailing afforded good stability by bypassing the bone defects.  相似文献   
56.
The levels of insulin-like growth factors 1 and 2 (IGF-1 and IGF-2) and somatomedin B in serum and cerebrospinal fluid (CSF) were investigated in alcoholic patients for 4 weeks after alcohol intake stopped. Throughout the observation period, CSF levels of IGF-2 were significantly decreased compared to those of healthy controls, whereas CSF levels of somatomedin B increased significantly 8 days after alcohol withdrawal and remained elevated throughout the observation period. CSF levels of IGF-2 were significantly correlated to measurements of ventricular enlargement on computed tomography. Somatomedin B levels were significantly correlated to clinical variables such as pulse, temperature, and agitation. No increase in the serum levels of somatomedin B were observed, but an increase in serum IGF levels was found in the patient group.  相似文献   
57.
58.
Lonomia achelous is a caterpillar distributed in southern Venezuela and in northern Brazil that causes an acute hemorrhagic syndrome in people who have contact with its bristles. The effect of the crude hemolymph and its chromatographic fractions (FDII, Lonomin V and Lonomin V-2) on extracellular matrix proteins was studied. The chromatographic fractions show activities similar to plasmin and urokinase. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both lonomins appear as a protein band of 25 kDa under reduced conditions. By exclusion chromatography, the molecular weights of Lonomin V and Lonomin V-2 were 26.5 and 24.5 kDa, respectively. Fibronectin, laminin and vitronectin were degraded by all venom components. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under reduced conditions, shows that lonomins degrade fibronectin in four main fragments of 116, 60, 50 and 30 kDa. Molecular exclusion chromatography in native conditions shows that the molecular masses of these fragments are > or = 300, 62 and 27 kDa. The proteolytic effect of lonomins was abolished by benzamidine/HCl, iodoacetic acid and aprotinin. The extracellular matrix protein degradation together with the fibrino(geno)lytic activity of hemolymph and its fractions could explain, in part, the hemorrhagic syndrome, and the wound dehiscence in persons who have had contact with the L. achelous caterpillar.  相似文献   
59.
This study was conducted to determine whether alcoholic and control subjects respond differently to manipulations that either enhance personal involvement (PI) or reduce negative affect (R, relaxation) on tests of neuropsychological function. In Phase 1, 48 male alcoholics and 36 male control subjects completed neuropsychological tasks under standard instructional sets. In Phase 2, subjects completed equivalent forms of these tests under one of three randomly assigned conditions; the PI condition in which subjects were encouraged to identify specific ways of improving their performance, the R condition in which subjects participated in a short relaxation exercise designed to reduce anxiety, or a No Treatment (NT) condition in which no attempt to manipulate the subjects' involvement or affect was made. Alcoholics were inferior to controls in both Phase 1 and Phase 2 [Fs (1,82) > 5.03, ps < 0.03]. The experimental manipulation differentially affected measures of negative affect and effort in the predicted direction. There were no group x condition interactions. Alcoholic and control subjects responded comparably to the experimental manipulations. This investigation, in combination with others using related manipulations, reinforces the hypothesis that alcohol-related cognitives dysfunction reflects an underlying deficit in brain states.  相似文献   
60.
The evolution of the progressive loss of semantic knowledge of a patient, VZ, with lesions mainly affecting the infero-medial temporal lobes, was followed for two years. At the beginning of the study VZ's performance was mainly characterized by a category-specific deficit for living things and a modality-specific deficit for perceptual attribute knowledge. As time went on, VZ's disorder affected all categories by changing the relationship between category and attribute knowledge. Data show that dissociations may change in the course of progressive cognitive breakdown, depending on both degeneration stage and task demands. VZ's performance is discussed in the light of the most influential theoretical accounts. Methodological suggestions regarding longitudinal studies of degenerative patients are also put forward.  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