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   71321篇
  免费   9040篇
  国内免费   370篇
耳鼻咽喉   1245篇
儿科学   1785篇
妇产科学   1906篇
基础医学   7337篇
口腔科学   4138篇
临床医学   9679篇
内科学   15947篇
皮肤病学   1250篇
神经病学   6782篇
特种医学   2727篇
外科学   10027篇
综合类   379篇
现状与发展   12篇
一般理论   44篇
预防医学   6287篇
眼科学   1123篇
药学   3623篇
  1篇
中国医学   65篇
肿瘤学   6374篇
  2024年   192篇
  2023年   1408篇
  2022年   980篇
  2021年   1764篇
  2020年   1945篇
  2019年   1452篇
  2018年   2501篇
  2017年   2338篇
  2016年   2738篇
  2015年   2852篇
  2014年   3676篇
  2013年   4843篇
  2012年   4529篇
  2011年   4681篇
  2010年   3695篇
  2009年   4072篇
  2008年   4003篇
  2007年   4060篇
  2006年   3826篇
  2005年   3697篇
  2004年   3306篇
  2003年   3071篇
  2002年   2803篇
  2001年   796篇
  2000年   615篇
  1999年   853篇
  1998年   1056篇
  1997年   935篇
  1996年   936篇
  1995年   729篇
  1994年   603篇
  1993年   566篇
  1992年   406篇
  1991年   379篇
  1990年   343篇
  1989年   360篇
  1988年   317篇
  1987年   292篇
  1986年   275篇
  1985年   302篇
  1984年   256篇
  1983年   255篇
  1982年   274篇
  1981年   226篇
  1980年   184篇
  1979年   144篇
  1978年   154篇
  1977年   174篇
  1976年   125篇
  1975年   134篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The goal of this longitudinal study was to investigate the precursors of early reading development in 52 children with cerebral palsy at kindergarten level in comparison to 65 children without disabilities. Word Decoding was measured to investigate early reading skills, while Phonological Awareness, Phonological Short-term Memory (STM), Speech Perception, Speech Production and Nonverbal Reasoning were considered reading precursors. Children with cerebral palsy lag behind on all reading precursors at the beginning of the second year of kindergarten. For the children without disabilities, early reading skills in Grade 1 were best predicted by Phonological Awareness and Phonological STM while Speech Production was the most important predictor of early reading success for the children with cerebral palsy, followed by Phonological Awareness and Speech Perception. Furthermore, for children with cerebral palsy, Speech Production appears to dominate reading development, as Speech Production measured at the beginning of the second year of kindergarten was strongly predictive of all other reading precursors measured at the end of the second year of kindergarten. The results of this study reveal that children with cerebral palsy with additional speech impairments are at risk for limited literacy development. Clinical implications are discussed.  相似文献   
82.
83.
84.
85.
86.
Treating hypertension reduces the rates of myocardial infarction, stroke, and renal disease; however, clinical trial experience suggests that monotherapy is not likely to be successful for achieving goal blood pressure (BP) levels in many hypertensive patients. In multiple recent clinical trials including various subsets of hypertensive patients, the achievement of BP goal has typically required the combination of 2 or more medications, particularly in patients with BP levels >160/100 mm Hg. When initiating combination therapy for hypertension, careful consideration must be given to the choice of medication. Clinical trial evidence has shown the efficacy of various combinations of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, and diuretics in reducing BP and cardiovascular risk. Ongoing trials should provide additional guidance on the optimal choice of combination regimens in specific clinical settings.  相似文献   
87.
PURPOSE: The purpose of this study was to measure spectrophotometrically the color stability of pigmented A-2186 silicone maxillofacial elastomer with 10% by volume of titanium white dry earth opacifier before and after exposure to microwave energy over a simulated 1.5-year period of microwave sterilization. Materials AND METHODS: A-2186 silicone elastomer opacified with titanium white dry earth pigment, pigmented with 5 cosmetic dry earth pigment colors [no pigment (control) group (Pc), red (Pr), yellow ochre (Py), burnt sienna (Po), and a mixture of Pr + Py + Po color group (P3)], was used in this study. Each of the 5 experimental groups consisted of 5 specimens. All specimens were placed in a 250 ml glass beaker filled with 150 ml of water (replenished for each microwave exposure). An exposure of 6 minutes was used 18 times (simulating 1.5 years of microwave sterilization with one 6 minute exposure monthly). Reflectance values were measured by spectrophotometer. Three- and two-way analyses of variance with repeated measures were performed for the color difference (DeltaE*) with the factors of group/color/months, and group/months, respectively. Means were compared by Tukey Honest Significant Difference (HSD) multiple range test calculated at the 0.05 level of significance using SPSS. RESULTS: The trained human eye can detect color changes (DeltaE*) greater than 1.0. Most DeltaE* values of the red pigment group at all intervals and the mixed pigment group at 15- and 18- month intervals increased significantly greater than 1.0 (p < 0.001) compared with the control group. Yellow and burnt sienna groups remained the most color stable over time with DeltaE* values below 0.35. CONCLUSIONS: Lack of color stability of red dry earth pigmented A-2186 silicone maxillofacial elastomers was clinically significant after 12-month exposure to microwave energy as compared with yellow, burnt sienna, and opacified A-2186 dry earth pigments.  相似文献   
88.
Summary The aim of the present study was to investigate the discriminative power of a series of variables (including determination of depressive symptomatology by means of a visual analogue scale, determination of personality traits by means of the Karolinska Scales of Personality, determination of monoamine metabolites in CSF, platelet MAO activities, serum cortisol before and after dexamethasone suppression and urinary melatonin) in differentiating (a) chronic pain patients from healthy subjects, and (b) patients with idiopathic pain syndromes from patients with neurogenic pain syndromes. Separately each of the measures gave a significant but often low contribution to the discrimination, while a combination of several measures gave a complete discrimination both between healthy subjects and patients with chronic pain syndromes and between patients with idiopathic and neurogenic pain syndromes, respectively.Supported in part by grants from the Swedish Medical Research Council (grants no. 3371, 4145 and 5740) and by a grant from Stiftelsen Söderström-Königska Sjukhemmet  相似文献   
89.
90.
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