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   3712篇
  免费   207篇
  国内免费   6篇
耳鼻咽喉   40篇
儿科学   137篇
妇产科学   113篇
基础医学   462篇
口腔科学   55篇
临床医学   219篇
内科学   882篇
皮肤病学   84篇
神经病学   294篇
特种医学   226篇
外科学   573篇
综合类   93篇
一般理论   1篇
预防医学   140篇
眼科学   160篇
药学   277篇
中国医学   11篇
肿瘤学   158篇
  2023年   34篇
  2022年   54篇
  2021年   114篇
  2020年   51篇
  2019年   76篇
  2018年   114篇
  2017年   72篇
  2016年   95篇
  2015年   119篇
  2014年   151篇
  2013年   153篇
  2012年   274篇
  2011年   282篇
  2010年   149篇
  2009年   127篇
  2008年   181篇
  2007年   202篇
  2006年   185篇
  2005年   155篇
  2004年   171篇
  2003年   134篇
  2002年   117篇
  2001年   107篇
  2000年   88篇
  1999年   63篇
  1998年   32篇
  1997年   19篇
  1996年   17篇
  1995年   15篇
  1992年   44篇
  1991年   34篇
  1990年   39篇
  1989年   33篇
  1988年   28篇
  1987年   31篇
  1986年   34篇
  1985年   25篇
  1984年   29篇
  1983年   20篇
  1982年   19篇
  1979年   14篇
  1978年   16篇
  1977年   16篇
  1975年   13篇
  1974年   15篇
  1973年   15篇
  1972年   12篇
  1970年   12篇
  1968年   14篇
  1967年   14篇
排序方式: 共有3925条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
A rich collection of empirical findings accumulated over the past three decades attests to the diversity of traits that constitute the autism phenotypes. It is unclear whether subsets of these traits share any underlying causality. This lack of a cohesive conceptualization of the disorder has complicated the search for broadly effective therapies, diagnostic markers, and neural/genetic correlates. In this paper, we describe how theoretical considerations and a review of empirical data lead to the hypothesis that some salient aspects of the autism phenotype may be manifestations of an underlying impairment in predictive abilities. With compromised prediction skills, an individual with autism inhabits a seemingly “magical” world wherein events occur unexpectedly and without cause. Immersion in such a capricious environment can prove overwhelming and compromise one’s ability to effectively interact with it. If validated, this hypothesis has the potential of providing unifying insights into multiple aspects of autism, with attendant benefits for improving diagnosis and therapy.  相似文献   
66.
Entertainment-education is an effective health communication strategy that combines or embeds educational messages into entertainment programs to bring about social and behavior change. For years, scholars have considered how entertainment-education works. Some contemporary theories posit that entertainment-education does not engender behavior change directly but does so through mediating variables. This study adds to the literature on this topic by exploring the direct relationship between exposure and social norms instead of their relationship through behavior as a mediator. Novel to this study is the use of encoded exposure, a continuous and recognition-based measure of exposure that includes ever watching, recall, involvement, and dose in its operationalization. Using cross-sectional data from Kyunki … Jeena Issi Ka Naam Hai, an entertainment-education program in India, this exploratory analysis indicates a positive and significant relationship between encoded exposure and social norms. How can this finding be applied to future programs? Questions remain, and replication is needed, but if it is not essential to go through behavior in order to change social norms, then implications emerge for the theory and practice of entertainment-education.  相似文献   
67.
The study evaluated the effect of commercial preparation of deltamethrin, Butox®, and fluoride (F?) co-exposure on the brain antioxidant status and cholinesterase activity in rats. Group A was untreated. Group B was gavaged Butox®, providing deltamethrin at the dose rate of 1.28?mg per kg body weight per day. Group C was administered F?, as NaF, in drinking water providing 20?ppm F?. Group D received both deltamethrin and F? at the same dosages as groups B and C, respectively. Although, glutathione S-transferase activity was induced only in Butox® alone treated group, the activities of superoxide dismutase and catalase were inhibited in all treatment groups when compared to the control group. Elevated lipid peroxidation was observed in the groups exposed to F?. The activity of erythrocyte acetylcholinesterase (AChE) was inhibited in Butox® treated groups, whereas brain AChE activity was inhibited in all treatment groups. In conclusion, both deltamethrin (given as Butox®) and F? inhibit AChE activity and produce oxidative stress in brain with F? producing more oxidative damage. However, compared to the individual exposures, the co-exposure of these chemicals does not produce any exacerbated alteration in these biochemical parameters.  相似文献   
68.
69.
Background: Extrahepatic portal venous obstruction (EHPVO) developing due to thrombotic occlusion of the portal vein in children is generally considered a benign disease. Whether hepatic dysfunction develops in these patients in the absence of a gastrointestinal bleed has not been well studied. Materials and methods: Forty‐three patients with EHPVO who had not bled in the last 3 months were studied. Patients were divided into those with (group I) or without ascites (group II). Matched cirrhotic patients with ascites (group III) served as controls. Clinical, biochemical, ultrasonographic, and histopathological evaluation was carried out. Portal biliopathy was assessed in five patients in group I and in 12 patients in group II by cholangiography. Results: Of 43 EHPVO patients, ascites was seen in nine (21%) patients (group I). Thirty‐four patients had no ascites (group II). Serum ALT (54±24 vs. 34±10 IU/l, P<0.01), albumin (3.2±0.3 vs. 3.7±0.4 g/dl, P<0.01), and prothrombin time difference (9.0±4.5 vs. 2.4±1.9 s, P<0.05) were deranged in patients in group I compared with group II. Patients in group I were 4 years older, and the duration of portal hypertension was longer than in group II (11.5 vs. 5.6 year, P<0.05). Portal biliopathy changes were significantly more severe in group I than in group II patients. Ascites was high gradient in all the patients in group I and the serum‐ascitic albumin gradient was comparable between groups I and III. None of the EHPVO patients, but four cirrhotic patients, developed spontaneous bacterial peritonitis during a follow‐up of 11±4 months. Conclusions: Hepatic dysfunction in the form of ascites and deranged liver functions is not uncommon in patients with EHPVO, more so in patients with prolonged portal hypertension. Based on our data it would be worthwhile to study whether prolonged portal vein thrombosis in EHPVO patients could lead to progressive liver disease.  相似文献   
70.
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