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   45577篇
  免费   3044篇
  国内免费   921篇
耳鼻咽喉   360篇
儿科学   1150篇
妇产科学   1198篇
基础医学   5081篇
口腔科学   794篇
临床医学   3954篇
内科学   10809篇
皮肤病学   701篇
神经病学   4122篇
特种医学   1702篇
外国民族医学   2篇
外科学   6132篇
综合类   2083篇
现状与发展   1篇
一般理论   1篇
预防医学   2375篇
眼科学   581篇
药学   3895篇
  8篇
中国医学   958篇
肿瘤学   3635篇
  2023年   400篇
  2022年   1054篇
  2021年   1610篇
  2020年   1025篇
  2019年   1102篇
  2018年   1237篇
  2017年   1022篇
  2016年   1069篇
  2015年   1356篇
  2014年   1769篇
  2013年   2174篇
  2012年   2848篇
  2011年   2854篇
  2010年   1722篇
  2009年   1583篇
  2008年   2420篇
  2007年   2460篇
  2006年   2266篇
  2005年   2146篇
  2004年   1959篇
  2003年   1700篇
  2002年   1531篇
  2001年   1414篇
  2000年   1339篇
  1999年   1243篇
  1998年   454篇
  1997年   334篇
  1996年   355篇
  1995年   272篇
  1994年   254篇
  1993年   210篇
  1992年   673篇
  1991年   570篇
  1990年   538篇
  1989年   550篇
  1988年   457篇
  1987年   419篇
  1986年   402篇
  1985年   315篇
  1984年   260篇
  1983年   211篇
  1982年   117篇
  1979年   211篇
  1978年   128篇
  1977年   111篇
  1974年   122篇
  1973年   125篇
  1972年   122篇
  1971年   110篇
  1969年   102篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
BACKGROUND/PURPOSE: Sensitive skin is a condition associated with reduced tolerance to environmental factors and/or the application of topical products, such as cosmetics. Its pathophysiology has not been fully elucidated and few data are available on its prevalence. The aim of this study was to investigate possible correlation between objective sensitivity and skin surface microrelief. METHODS: During an epidemiological survey conducted for a campaign promoted by International Society of Plastic Dermatology in Italy, 243 adult healthy subjects of both sexes with no evident dermatological disorder but positive to the lactic acid stinging test, were submitted to cyanoacrylate stratum corneum stripping from the volar forearm for the determination of the irregularity of the skin surface microrelief (irregularity skin index (ISI)). RESULTS: A significant correlation was found between intensity of symptoms in stingers and ISI (r(s)=-0.47; P<0.001). CONCLUSION: Sensitive skin is common in the healthy population. ISI can contribute towards the identification of subjects with sensitive skin and the development of more specific skin treatments for this prevalent condition.  相似文献   
32.
OBJECTIVE: The study aims to verify whether phonologic and rapid automatized naming (RAN) deficits are present and associated in Italian dyslexic children and whether they differentially affect dyslexics with and without a history of previous language delay (LD). BACKGROUND: According to the phonologic core deficit hypothesis, dyslexia may stem from impairment of the representation and manipulation of phonemes and may be closely associated with oral language deficits. However, deficits in tasks not requiring fine-grained phonologic representations, such as RAN, have also been described in dyslexic children. METHODS: Thirty-seven children were selected on the basis of a reading deficit and were assigned to 2 groups according to whether or not they had a history of early LD as determined retrospectively by parental report. A battery of reading and writing, verbal working memory, metaphonologic, RAN, and visual search tests were administered. RESULTS: RAN deficits were shared by most dyslexics (with and without a history of LD), whereas phonologic deficits were mainly associated with a previous LD. This last condition did not result in a more profound impairment of reading and writing decoding skills. CONCLUSION: In a shallow orthography such as Italian, RAN, not phonologic deficits, may represent the main cognitive marker of developmental dyslexia.  相似文献   
33.
34.
BACKGROUND: In the central nervous system, several neuropeptides are believed to be involved in the pathophysiology of Alzheimer's disease (AD). Indeed, previous studies have documented that glucagon-like peptide 1 (GLP-1) possesses neurotropic properties and can reduce amyloid-beta peptide levels in the brain in vivo. Moreover, the concentrations of neuropeptide Y (NPY) seem to be altered in the cerebrospinal fluid of patients with AD and in subjects with major depression. Finally, among the modifications induced by aging, a dysregulation of the ghrelin-growth hormone (GH) system has been reported. METHODS: We investigated the plasma concentrations of these neuropeptides in 14 subjects with AD. Data obtained from these patients were compared with data from an age- and weight-matched healthy group. RESULTS: No significant differences were found between the two groups in relation to plasma levels of GLP-1, NPY, ghrelin and GH. Peripheral NPY concentrations were positively correlated with ghrelin levels in both groups, and with plasma GLP-1 concentration only in controls. CONCLUSION: On the basis of our results, peripheral levels of these neuropeptides seem not to serve as biochemical markers of AD.  相似文献   
35.
糖化血红蛋白(Hb)A1c是血糖监测的苇要指标,反映检测前2~3个月的平均血糖水平.慢性肾功能衰竭(CRF)患者存在贫血、酸中毒、氧化应激、胰岛素抵抗、血液透析及促红细胞生成素(EPO)的应用等因素,对HbA1c的测定会造成影响.糖化血清蛋白(GSP)反映检测前2~3周的平均血糖水平,仅受血浆蛋白的影响,几乎不受血红蛋白和EPO治疗等以上因素的影响,且对短时间内的血糖变化更为敏感.将GSP作为糖尿病肾功能衰竭患者血糖监测指标可能比HbA1c更理想.  相似文献   
36.
37.
The introduction of new diagnostic tools for neuroimaging has resulted in the early recognition of congenital brain tumors. In the present report we describe a personal series of 39 children and an International Multicenter Series of 876 children with brain tumors, in whom the diagnosis was obtained during the first 12 months of life. Most of the tumors were located within the supratentorial compartment. In spite of a relatively high operative mortality, surgery still appears to be the more effective therapy. Radiotherapy in this age group is of a scarce value, due to the vulnerability of the infantile brain. At the present time, chemotherapy still plays a controversial role.  相似文献   
38.
AClinicalStudyofReversingLeftVentricularHypertrophyinHypertensivePatientsbyAdalatZhangFumin(张馥敏)XuDi(许迪)YongYonghong(雍永宏)Chen...  相似文献   
39.
40.
The presence of cellular retinoic acid binding protein (cRABP) was analyzed in 13 consecutive patients with large bowel cancer (one right colon and 12 rectum-sigmoid, classified as three Duke B, eight C, and two D). Specimens of neoplastic tissue and of adjacent mucosa were obtained at surgery, and cRABP was determined by an assay based on incubation of partially purified cytosol with labeled retinoic acid and ultracentrifugation in sucrose density gradients. Sixty-one percent of tumors contained detectable levels of cRABP, whereas 58.3% of normal mucosal specimens were positive for cRABP. Among the positive tumors 62.5% contained cRABP also in the corresponding mucosa; in the group of cRABP-negative tumors, 40% showed cRABP in the adjacent mucosa. No correlation could be established with the grading or the stage of the tumors; however, interestingly, 100% (three cases) of gelatinous carcinomas were cRABP positive. Since cRABP seems to be a character of neoplastic cells contrary to normal ones, it would be interesting to investigate the conditions that influence the presence of this protein in normal appearing mucosa adjacent to carcinoma.  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