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   1383095篇
  免费   102433篇
  国内免费   2235篇
耳鼻咽喉   20009篇
儿科学   47383篇
妇产科学   37240篇
基础医学   196405篇
口腔科学   37423篇
临床医学   117796篇
内科学   283694篇
皮肤病学   31352篇
神经病学   108737篇
特种医学   53519篇
外国民族医学   661篇
外科学   208963篇
综合类   27632篇
现状与发展   1篇
一般理论   406篇
预防医学   106147篇
眼科学   30275篇
药学   102076篇
  2篇
中国医学   2958篇
肿瘤学   75084篇
  2019年   11498篇
  2018年   17224篇
  2017年   12377篇
  2016年   13173篇
  2015年   14916篇
  2014年   20015篇
  2013年   30534篇
  2012年   43788篇
  2011年   46285篇
  2010年   26859篇
  2009年   24644篇
  2008年   43153篇
  2007年   46183篇
  2006年   45964篇
  2005年   44830篇
  2004年   43198篇
  2003年   41756篇
  2002年   40725篇
  2001年   66695篇
  2000年   69685篇
  1999年   58749篇
  1998年   15532篇
  1997年   14000篇
  1996年   14436篇
  1995年   13639篇
  1994年   12904篇
  1993年   11930篇
  1992年   45493篇
  1991年   44284篇
  1990年   42928篇
  1989年   40708篇
  1988年   37375篇
  1987年   36718篇
  1986年   34097篇
  1985年   32708篇
  1984年   24436篇
  1983年   20501篇
  1982年   11840篇
  1981年   10794篇
  1979年   21606篇
  1978年   14993篇
  1977年   12694篇
  1976年   11876篇
  1975年   12855篇
  1974年   14932篇
  1973年   14409篇
  1972年   13198篇
  1971年   12008篇
  1970年   11303篇
  1969年   10277篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
Premalignant lesions of the penis include cutaneous horn, balanitis xerotica obliterans, and leukoplakia. The true incidence of progression of each of these to squamous-cell carcinoma is unknown. Bowenoid papulosis, erythroplasia of Queyrat, and Bowen's disease are histologically identical to in situ carcinoma. Although the first is consistently benign, the latter two regularly evolve into invasive cancer. Malignant scrotal lesions include squamous-cell carcinoma, liposarcoma, leiomyosarcoma, basal-cell carcinoma, extramammary Paget's disease, erythroplasia of Queyrat, malignant melanoma, and metastases. Hemangioma can be confused with carcinoma.  相似文献   
92.
Background: The association between aluminium and dialysis encephalopathy and deterioration of the neurological state during desferrioxamine treatment of dialysis patients is well established. At present little is known about the speciation and the mechanisms underlying the element's neurotoxicity. Methods. Aluminium speciation was performed in cerebrospinal fluid samples of acutely aluminium-intoxicated dialysis patients using a recently developed high-performance liquid chromatographic/electro-thermal atomic absorption spectrometric hybrid method. Results: Baseline cerebrospinal fluid aluminium levels of samples taken shortly after the intoxication were low but elevated (5.0±2.0 &mgr;g/l, n=3) as compared to subjects with normal renal function (<1 &mgr;g/l). In contrast to the situation noted in serum and to the iron speciation in cerebrospinal fluid, aluminium was not bound to transferrin but appeared as two distinct compounds, the main fraction eluting at the elution volume of aluminium citrate/silicate. The second compound was not identified. Forty-four hours after desferrioxamine administration the cerebrospinal fluid aluminium levels had increased up to a concentration of 10.3±2.5 &mgr;g/l (n=3). This was accompanied by a change in the speciation profile with aluminium appearing at the elution volume of aluminoxamine. Conclusion: Our findings may contribute to a better understanding of the neurotoxic effects of aluminium and its desferrioxamine chelate in dialysis patients.  相似文献   
93.
94.
The authors aimed at evaluating the impact of psychotraumas in psychiatric outpatients. One hundred forty psychiatric outpatients were consecutively included, without distinction of their current pathology. They filled in an inventory of potentially traumatic experiences, a psychological dissociative experiences scale, a somatoform dissociative experiences questionnaire, and underwent a structured interview for diagnosis of posttraumatic stress disorder (according to the DSM-IV). One hundred subjects related psychological trauma, and 76 patients suffered from posttraumatic stress disorder. Dissociative disorders are found significantly correlated with traumatic experience and to posttraumatic stress disorder. The traumatic impact is found more substantial as the number of events was elevated. This study confirms the elevated prevalence of the psychological traumas and psychotraumatic aftermaths in outpatients of a department of psychiatry, independently from the mental disorder.  相似文献   
95.
96.
Duration of the speech disfluencies of beginning stutterers   总被引:1,自引:0,他引:1  
This study compared the duration of within-word disfluencies and the number of repeated units per instance of sound/syllable and whole-word repetitions of beginning stutterers to those produced by age- and sex-matched nonstuttering children. Subjects were 10 stuttering children [9 males and 1 female; mean age 4:1 (years:months); age range 3:2-5:1), and 10 nonstuttering children (9 males and 1 female; mean age 4:0; age range: 2:10-5:1). Mothers of the stuttering children reported that their children had been stuttering for 1 year or less. One 300-word conversational speech sample from each of the stuttering and nonstuttering children was analyzed for (a) mean duration of sound/syllable repetition and sound prolongation, (b) mean number of repeated units per instance of sound/syllable and whole-word repetition, and (c) various related measures of the frequency of all between- and within-word speech disfluencies. There were no significant between-group differences for either the duration of acoustically measured sound/syllable repetitions and sound prolongations or the number of repeated units per instance of sound/syllable and whole-word repetition. Unlike frequency and type of speech disfluency produced, average duration of within-word disfluencies and number of repeated units per repetition do not differentiate the disfluent speech of beginning stutterers and their nonstuttering peers. Additional analyses support findings from previous perceptual work that type and frequency of speech disfluency, not duration, are the principal characteristics listeners use in distinguishing these two talker groups.  相似文献   
97.
The Authors examine the correlation between hypertensive disorders of pregnancy and fetal growth. The results of a study of 342 pregnancies, confirm a significant correlation between hypertension and fetal growth retardation. These findings, so evident in moderate and severe hypertension, have also been confirmed in cases of mild hypertension. The medical treatment also in the pregnancies with mild hypertension, and a larger utilisation of operative deliveries, determined a decrease in perinatal mortality and morbidity.  相似文献   
98.
Background The appearance of eosinophils is a hallmark sign of the allergic late-phase response (LPR). Eosinophil cationic protein (ECP), a readily measurable product released from activated eosinophils, has so far not been evaluated in the ocular LPR. Objective Two sets of trials were performed in order to investigate changes of local and systemic eosinophil activity and their possible link with symptoms and hyper-reactivity in the allergic LPR in the eye. Methods In the first experiment, ECP was analysed in tears and serum and the clinical reaction was evaluated during a 72-h time–course after a single, high-dose allergen challenge out of season in one eye of 15 pollen-sensitized volunteers. In a second experiment, the hypothesis of an increased clinical response to an allergen challenge in an eye that had been provoked with allergen 48h previously was tested in nine sensitized individuals. Results In the first experiment, symptoms at 10 min and 2, 4, 6, 8 and 24 h significantly exceeded base line scores of the challenged eyes. Tear ECP was significantly elevated in challenged eyes compared to contralateral eyes at 6, 8 and 24 h. In addition, symptoms and ECP release correlated significantly at the 24-h evaluation. Serum ECP remained unchanged throughout the study period. In the second experiment, conjunctival hyperreactivity 48h after an allergen challenge was not confirmed. Conclusion ECP secretion occurs in the experimental ocular LPR and is in part associated with the magnitude of the clinical reaction, which suggests a truly pathogenic role of the activated eosinophil in pollen-induced allergic conjunctivitis.  相似文献   
99.
100.
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