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   7378篇
  免费   322篇
  国内免费   20篇
耳鼻咽喉   29篇
儿科学   111篇
妇产科学   105篇
基础医学   844篇
口腔科学   227篇
临床医学   514篇
内科学   1853篇
皮肤病学   124篇
神经病学   603篇
特种医学   343篇
外国民族医学   1篇
外科学   1509篇
综合类   36篇
预防医学   239篇
眼科学   125篇
药学   513篇
中国医学   10篇
肿瘤学   534篇
  2022年   63篇
  2021年   109篇
  2020年   56篇
  2019年   100篇
  2018年   107篇
  2017年   92篇
  2016年   97篇
  2015年   122篇
  2014年   166篇
  2013年   178篇
  2012年   320篇
  2011年   297篇
  2010年   167篇
  2009年   164篇
  2008年   322篇
  2007年   289篇
  2006年   318篇
  2005年   326篇
  2004年   306篇
  2003年   298篇
  2002年   322篇
  2001年   242篇
  2000年   240篇
  1999年   224篇
  1998年   96篇
  1997年   78篇
  1996年   50篇
  1995年   53篇
  1994年   52篇
  1992年   187篇
  1991年   213篇
  1990年   191篇
  1989年   171篇
  1988年   164篇
  1987年   171篇
  1986年   134篇
  1985年   141篇
  1984年   112篇
  1983年   99篇
  1982年   49篇
  1979年   78篇
  1978年   51篇
  1975年   50篇
  1973年   41篇
  1971年   49篇
  1970年   41篇
  1969年   53篇
  1968年   54篇
  1967年   42篇
  1966年   52篇
排序方式: 共有7720条查询结果,搜索用时 15 毫秒
11.
12.
Abstract: Cardiopulmonary support (CPS) requires durability of the oxygenator. The life span of the oxygenator is affected by various clinical factors, including patient condition, perfusion condition, and equipment usage. Predictors for the durability of oxygenators were evaluated clinically in this study. Thirty-two patients, who had undergone CPS during the last 3 years in our institute were assigned to this study. Fifty oxygenators had been used (Capiox SX in 19, CB Maxima in 23, and AL-6000 in 8). Significant predictors for the durability of oxygenators were evaluated by nonparametric survival analysis and proportional hazards regression analysis. Univariate regression analysis revealed 6 significant predictors for the life span of oxygenators. These were the oxygenator type, type of centrifugal pump, acidosis with blood pH less than 7.35, base excess less than -5, blood glutamic-oxaloacetic transaminase (GOT) levels greater than 1,000 IU, and blood lactate dehydrogenase (LDH) levels greater than 3,000 IU. After multivariate analysis, there remained only 2 significant predictors. An oxygenator used with a noncoated CPS system (Capiox SX with Capiox EBS) proved to have a significantly shorter life span than one used with a heparin-coated system (CB Maxima or AL-6000 with CB BP-80) (hazards ratio, 3.588, p = 0.0065). Patient conditions, which revealed acidosis with less than -5 of base excess, significantly shortened the life of the oxygenator (hazards ratio, 3.595, p = 0.0188).  相似文献   
13.
Abstract:  Carbohydrate (Carb) counting is a meal planning approach for patients with diabetes mellitus that focuses on carbohydrate as the primary nutrient affecting postprandial glycemic response. The concept of carb counting is not new. In the early 1990`s the Diabetes Control and Complications Trial (DCCT) used carb counting as one of its education tools. More recently, short acting insulin analogues and insulin pumps have made the role of carb counting important and popular. Carb counting can be used in conjunction with a meal plan to set carbohydrate targets at each meal and snack. It is also used, perhaps more commonly, to estimate carbohydrate intake and adjust insulin around mixed meals and snacks using insulin to carbohydrate ratio. This effectively addresses the variable eating habits of most children and adolescents. The method may be adapted for patients who use a conventional insulin regimen and may meet the needs of patients who use multiple daily injections (MDI) or an insulin pump. Carb counting can make food planning flexible and enjoyable for patients, and the meal planning approach is very important for the physical growth and psychological development of children with diabetes. This paper describes the importance of carb counting for childhood diabetes as well as some of the special aspects associated with it.  相似文献   
14.
Lesions in the thalamus or basal ganglia have rarely been reported in acute disseminated encephalomyelitis (ADEM). We experienced 2 cases of ADEM, in which MRI showed lesions in the thalamus or basal ganglia. Case 1, a 4-year-old boy, had gait disturbance, hyperesthesia and hyperreflexia. MRI (T2 weighted image) showed multiple high intensity areas in the right frontal lobe, bilateral parietal lobes and bilateral thalami. Case 2, a 4-year-old girl, complained of gait disturbance following a febrile episode, and displayed hyperreflexia. Several days later, she had visual disturbance of the left eye. MRI (T2 weighted image) revealed multiple high intensity areas in the dentate nucleus of left cerebellum, left occipital lobe, bilateral caudate nuclei, and the anterior part of bilateral lenticular nuclei. In both cases, CT could not demonstrate these lesions. Both of them were treated with corticosteroid and recovered rapidly. They had no recurrence. MRI is useful in diagnosis and follow-up of ADEM and may reveal lesions other than cerebral or cerebellar white matters.  相似文献   
15.
Aim:  To compare the clinical outcomes of cryopreserved-thawed embryo transfer among patients with a normal menstrual cycle who had natural or hormone-replacement cycles.
Methods:  From January 2004 to June 2006, cryopreserved embryos following conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) were thawed and transferred in a total of 720 natural cycles and 136 hormone-replacement cycles.
Results:  Cryopreserved-thawed embryo transfer in patients who had a natural or hormone-replacement cycle resulted in clinical pregnancy in 43.1% and 40.4%, respectively; a rate of miscarriage of 14.5% and 23.6%, respectively; and a rate of ongoing pregnancy and delivery of 36.5% and 30.9%, respectively. None of these differences were statistically significant.
Conclusions:   Patients with a normal menstrual cycle who have natural or hormone-replacement cycles can be expected to have comparable clinical outcomes with cryopreserved-thawed embryo transfer. (Reprod Med Biol 2007; 6 : 53–57)  相似文献   
16.
17.
18.
19.
20.
OBJECTIVE: The purpose of this study was to develop and characterize human monoclonal antibodies (HuMAb) that neutralize HIV-1. DESIGN: Based upon previous studies involving the generation of HuMAb that neutralize other enveloped viruses, we thought it feasible to generate HuMAb that might neutralize HIV-1. METHODS: A HuMAb was generated by fusing splenic B-cells from an HIV-positive patient with a mouse myeloma cell line. Flow cytometry was used to determine surface reactivity of the HuMAb on HIV-infected and non-infected cells. Radioimmunoprecipitation was employed to elucidate the antigen recognized by the HuMAb. A cell survival assay was used to determine the ability of the HuMAb to neutralize divergent isolates of HIV-1 in the presence or absence of complement. A gp120-CD4 inhibition enzyme-linked immunosorbent assay (ELISA) was developed in order to initiate studies to determine the mechanism of neutralization by the HuMAb. RESULTS: An anti-HIV HuMAb was generated that neutralized two HIV-1 isolates (IIIB and MN) without complement and which neutralized one divergent isolate (RF) and one clinical isolate in the presence of complement. This HuMAb, designated S1-1, was found, by flow cytometric analysis, to react with the surface of HIV-1-infected but not with uninfected cells. Radioimmunoprecipitation analysis demonstrated that S1-1 binds to native HIV gp120, but not dithiothreitol (DTT)-treated gp120. In addition, HuMAb S1-1 did not bind to denatured HIV antigens in Western blot analysis. HuMAb S1-1 effectively inhibited the binding of gp120 to soluble CD4 in ELISA. CONCLUSIONS: These results suggest that the epitope recognized by S1-1 is conformational and conserved among diverse HIV-1 isolates and may represent an uncharacterized HIV neutralizing domain within or close to the CD4 binding domain on gp120. HuMAb S1-1 might have a role to play in vaccine development or passive immunotherapy.  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