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   4341篇
  免费   227篇
  国内免费   35篇
耳鼻咽喉   62篇
儿科学   97篇
妇产科学   105篇
基础医学   566篇
口腔科学   93篇
临床医学   315篇
内科学   1178篇
皮肤病学   100篇
神经病学   376篇
特种医学   84篇
外科学   340篇
综合类   21篇
预防医学   361篇
眼科学   117篇
药学   339篇
中国医学   30篇
肿瘤学   419篇
  2024年   4篇
  2023年   31篇
  2022年   81篇
  2021年   133篇
  2020年   89篇
  2019年   111篇
  2018年   139篇
  2017年   90篇
  2016年   98篇
  2015年   128篇
  2014年   145篇
  2013年   195篇
  2012年   353篇
  2011年   329篇
  2010年   181篇
  2009年   158篇
  2008年   312篇
  2007年   297篇
  2006年   287篇
  2005年   248篇
  2004年   234篇
  2003年   221篇
  2002年   220篇
  2001年   46篇
  2000年   39篇
  1999年   47篇
  1998年   37篇
  1997年   35篇
  1996年   34篇
  1995年   30篇
  1994年   25篇
  1993年   17篇
  1992年   26篇
  1991年   20篇
  1990年   20篇
  1989年   17篇
  1988年   16篇
  1987年   8篇
  1986年   8篇
  1985年   14篇
  1984年   7篇
  1983年   6篇
  1982年   6篇
  1981年   6篇
  1980年   6篇
  1979年   5篇
  1978年   7篇
  1977年   4篇
  1976年   4篇
  1975年   4篇
排序方式: 共有4603条查询结果,搜索用时 0 毫秒
81.
Neurological Sciences - The Frontal Assessment Battery (FAB) is a neuropsychological tool largely used to assess executive functions. Prior studies found a marked ceiling effect for the prehension...  相似文献   
82.
BACKGROUND: Although prior studies used the 66-item Rapid Estimate of Adult Literacy in Medicine (REALM instrument) for literacy assessment, researchers may require a shorter, validated instrument when designing interventions for clinical contexts. OBJECTIVE: To develop and validate a very brief literacy assessment tool, the REALM-Short Form (REALM-SF). PATIENTS: The model development, validation, and field testing validation samples included 1336, 164, and 50 patients, respectively. SETTING: General medicine and subspecialty clinics and medicine inpatient wards. DESIGN: For development and validation samples, indicator variables for REALM instrument items were evaluated as potential predictors of REALM instrument score by stepwise multiple regression analysis with subsequent bootstrap and confirmatory factor analysis of selected items. Pearson correlations compared REALM-SF and REALM instrument scores and kappa analyses compared grade level assignments. For the field testing validation sample, Pearson correlations compared Wide Range Achievement Test and REALM-SF scores. RESULTS: The REALM-SF included 7 items with stable model coefficients and 1 underlying linear factor. REALM-SF and REALM instrument scores were highly correlated in development (r = 0.95, P < 0.001) and validation (r = 0.94, P < 0.001) samples. There was excellent agreement between REALM-SF and REALM instrument grade-level assignments when dichotomized at the 6th grade (development: 97% agreement, K = 0.88, P < 0.001; validation: 88% agreement, K = 0.75, P < 0.001) and 8th grade levels (development: 94% agreement, K = 0.78, P < 0.001; validation: 84% agreement, K = 0.67, P < 0.001). REALM-SF and Wide Range Achievement Test scores were highly correlated (r = 0.83, P < 0.001) in field testing validation. CONCLUSIONS: The REALM-SF provides researchers a brief, validated instrument for assessing patient literacy in diverse research settings.  相似文献   
83.
The modern removable partial denture (RPD), in response to the increased esthetic demands of our patients, is no longer acceptable if it requires visible buccal and facial clasp arms for retention. By eliminating the bracing arm and having its functions taken by paralleled guide planes and precise, positive rests, the retentive element, a lingual circumferential wire clasp arm, will provide the same amount of retentive force as if it were placed on the buccal surface and will not be visible. Designs for the major connector either plate the lingual surface of the abutment or, as in a lingual bar, leave that surface open. Both of these situations are adaptable to the lingual retentive clasp and are illustrated in this article. CLINICAL SIGNIFICANCE: Design features such as metal clasps needed for the retention of RPDs can be very unsightly, creating an esthetic problem. This article reviews the concepts for creating lingual clasp arms that enhance the esthetic quality of prostheses.  相似文献   
84.
Genetic studies have demonstrated that nonsyndromic cleft is composed of two separate entities: the cleft palate only and cleft of the lip, alveolus with or without cleft palate; both have a heterogeneous genetic background and environmental factors contribute to the onset of these malformations. The role of transforming growth factor alpha (TGF-A) was considered possible, but conflicting results have been reported. To detect if TGF-A is involved in the onset of cleft diseases, a series of patients with nonsyndromic clefts and control subjects were analyzed with regard to protein expression. Forty-three patients with nonsyndromic clefts and 21 unaffected subjects were enrolled in this study. Paraffin-embedded specimens were matched with TGF-A antibody and then scanned with a computerized image analyzer. TGF-A was scored as absent, moderately (from 10% to 30%), and highly expressed in epithelium, gland, and muscle. Data were statistically analyzed with a Kruskal-Wallis test. Comparison between control subjects and patients with clefts showed that only gland and epithelium reached a significant P value. A subsequent comparison between cleft of the lip, alveolus with or without cleft palate and cleft palate only groups demonstrated a statistically significant difference only for gland. TGF-A was decreasingly expressed in unaffected, cleft of the lip, alveolus with or without cleft palate, and patient with cleft palate only and thus further strength has been given to its role in the onset of the disease.  相似文献   
85.
Fonsecaea pedrosoi is the most common etiologic agent of chromoblastomycosis. F. pedrosoi and other dematiaceous fungi are usually identified by morphologic studies. We have developed a duplex polymerase chain reaction (PCR) targeting the ribosomal DNA for rapid and more specific identification of the genus Fonsecaea. DNA samples from 103 isolates of Fonsecaea species and other dematiaceous fungi were amplified by PCR using universal and specific primers targeting ITS1-5.8S-ITS2 region of the ribosomal DNA. Universal primers were used for detection of non-Fonsecaea DNA. Fonsecaea-specific PCR product was found in 70 (68.0%) isolates including 4 strains that did not develop conidiogenesis. Thirty non-Fonsecaea and 3 Fonsecaea compacta isolates were negative by duplex PCR. These results were confirmed by DNA sequencing analysis indicating the high specificity of the duplex PCR assay. In conclusion, the duplex PCR is a rapid and specific assay for identification of Fonsecaea isolates mainly for the strains that are difficult to identify by morphologic methods.  相似文献   
86.
Hepatotoxicity related to HDS is a growing global health issue. We have undertaken a systematic review of published case reports and case series from LA from 1976 to 2020 to describe the clinical features of HDS related hepatotoxicity in this region. We search in PubMed, Web of Science, Scopus and specific LA databases according to PRISMA guidelines. Only HILI cases published in LA that met criteria for DILI definition were included. Duplicate records or reports that lacked relevant data that precluded establishing causality were excluded. Finally, 17 records (23 cases) were included in this review. Centella asiatica, Carthamus tinctorius, and Herbalife® were the most reported HDS culprit products, the main reason for HDS consumption was weight loss. The clinical characteristics of HDS hepatotoxicity in our study were compared to those of other studies in the USA, Europe and China showing a similar signature with predominance of young females, hepatocellular damage, a high rate of ALF and mortality, more frequent inadvertent re‐challenge and chronic damage. This study underscores the challenge in causality assessment when multi‐ingredients HDS are taken and the need for consistent publication practice when reporting hepatotoxicity cases due to HDS, to foster HDS liver safety particularly in LA.  相似文献   
87.
88.
Friedreich's ataxia is a rare degenerative neuromuscular disorder, caused by a homozygous GAA triplet repeat expansion in the frataxin (FXN) gene, with a broad clinical phenotype characterized by progressive gait and limb ataxia, dysarthria, and loss of lower limb reflexes; cardiac involvement is represented by hypertrophic cardiomyopathy, ventricular arrhythmias, and sudden cardiac deaths. Currently, no definite therapy is available, while many drugs are under investigation; for this reasons, we need markers of short- and long-term treatment efficacy acting on different tissue for trial evaluation. We describe the case of a 21-year-old patient affected by Friedreich's ataxia on wheel-chair, with initial cardiac involvement and electrocardiographic features characterized by thiamine treatment-related negative T wave and QTc variations. We discuss plausible physiopathology and potential ECG role implications as an intermediate marker of treatment response in future clinical trials considering patients affected by Friedreich's ataxia.  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