全文获取类型
收费全文 | 53864篇 |
免费 | 3750篇 |
国内免费 | 133篇 |
专业分类
耳鼻咽喉 | 433篇 |
儿科学 | 1977篇 |
妇产科学 | 1846篇 |
基础医学 | 6497篇 |
口腔科学 | 1009篇 |
临床医学 | 9083篇 |
内科学 | 9940篇 |
皮肤病学 | 835篇 |
神经病学 | 4754篇 |
特种医学 | 1041篇 |
外国民族医学 | 33篇 |
外科学 | 4702篇 |
综合类 | 726篇 |
一般理论 | 80篇 |
预防医学 | 7389篇 |
眼科学 | 637篇 |
药学 | 3030篇 |
1篇 | |
中国医学 | 138篇 |
肿瘤学 | 3596篇 |
出版年
2023年 | 325篇 |
2022年 | 457篇 |
2021年 | 1150篇 |
2020年 | 766篇 |
2019年 | 1169篇 |
2018年 | 1383篇 |
2017年 | 934篇 |
2016年 | 1055篇 |
2015年 | 1190篇 |
2014年 | 1617篇 |
2013年 | 2591篇 |
2012年 | 3698篇 |
2011年 | 3961篇 |
2010年 | 2147篇 |
2009年 | 1966篇 |
2008年 | 3453篇 |
2007年 | 3886篇 |
2006年 | 3719篇 |
2005年 | 3585篇 |
2004年 | 3439篇 |
2003年 | 3271篇 |
2002年 | 3087篇 |
2001年 | 448篇 |
2000年 | 343篇 |
1999年 | 456篇 |
1998年 | 712篇 |
1997年 | 559篇 |
1996年 | 485篇 |
1995年 | 393篇 |
1994年 | 405篇 |
1993年 | 393篇 |
1992年 | 294篇 |
1991年 | 252篇 |
1990年 | 239篇 |
1989年 | 201篇 |
1988年 | 202篇 |
1987年 | 223篇 |
1986年 | 179篇 |
1985年 | 208篇 |
1984年 | 222篇 |
1983年 | 222篇 |
1982年 | 281篇 |
1981年 | 252篇 |
1980年 | 200篇 |
1979年 | 145篇 |
1978年 | 126篇 |
1977年 | 141篇 |
1976年 | 122篇 |
1975年 | 100篇 |
1973年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Andrea DiMartini Nancy Day Mary Amanda Dew Lubna Javed Mary Grace Fitzgerald Ashok Jain John J Fung Paulo Fontes 《Liver transplantation》2006,12(5):813-820
For patients who receive a liver transplant (LTX) for alcoholic liver disease (ALD), investigators are focusing beyond survival to determine specific alcohol use outcomes. Studies suggest the use of alcohol ranges from 8 to 22% for the first post-transplant year with cumulative rates reaching 30 to 40% by 5 years following transplantation. Yet while investigators are interested in determining specific rates of alcohol use and predictors of use, only three studies since 1990 have been prospective. In 1998, we began a prospective study of post-LTX alcohol consumption in ALD recipients using multiple repeated measures of alcohol use. After 5 years of follow-up, we found that 22% had used any alcohol by the first year and 42% had a drink by 5 years. By 5 years, 26% drank at a heavier use (binge) pattern and 20% drank in a frequent pattern. In a univariate model, predictors of alcohol use included pre-transplant length of sobriety, a diagnosis of alcohol dependence, a history of other substance use, and prior alcohol rehabilitation. 相似文献
32.
Mary Ann Richardson Helen M Chao Laura L Read James D Clelland Raymond F Suckow 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(2):195-197
Phenylketonuria (PKU), an inborn error of phenylalanine metabolism, has been shown to be a risk factor for tardive dyskinesia (TD). In male psychiatric patients there was a significant relationship between TD and measures of plasma phenylalanine following ingestion of a standardized phenylalanine dose that was indicative of higher brain availability of phenylalanine in patients with TD. In addition, a medical food formulation consisting of branched chain amino acids, which compete with phenylalanine for transport across the blood-brain barrier, has been demonstrated to be an efficacious treatment for TD. Cumulatively these findings suggested that TD was related to phenylalanine metabolism and thus that sequence variants in the gene for phenylalanine hydroxylase (PAH), the rate-limiting enzyme in the catabolism of phenylalanine, could be associated with TD susceptibility. Genetic screening of PAH in a group of 123 psychiatric patients revealed ten sequence polymorphisms and two mutations, but none appeared to be a significant risk factor for TD. 相似文献
33.
Akira Sawaki Nobumasa Mizuno Kuniyuki Takahashi Tsuneya Nakamura Masahiro Tajika Hiroki Kawai Toshifumi Isaka Hiroshi Imaoka Yasuyuki Okamoto Masatoshi Aoki Hiroyuki Inoue Ahmed AS Salem Yasushi Yatabe Kenji Yamao 《Digestive endoscopy》2006,18(1):40-44
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed. 相似文献
34.
BCR-ABL activity and its response to drugs can be determined in CD34+ CML stem cells by CrkL phosphorylation status using flow cytometry. 总被引:2,自引:0,他引:2
A Hamilton L Elrick S Myssina M Copland H J?rgensen J V Melo T Holyoake 《Leukemia》2006,20(6):1035-1039
In chronic myeloid leukaemia, CD34(+) stem/progenitor cells appear resistant to imatinib mesylate (IM) in vitro and in vivo. To investigate the underlying mechanism(s) of IM resistance, it is essential to quantify Bcr-Abl kinase status at the stem cell level. We developed a flow cytometry method to measure CrkL phosphorylation (P-CrkL) in samples with <10(4) cells. The method was first validated in wild-type (K562) and mutant (BAF3) BCR-ABL(+) as well as BCR-ABL(-) (HL60) cell lines. In response to increasing IM concentration, there was a linear reduction in P-CrkL, which was Bcr-Abl specific and correlated with known resistance. The results were comparable to those from Western blotting. The method also proved to be reproducible with small samples of normal and Ph(+) CD34(+) cells and was able to discriminate between Ph(-), sensitive and resistant Ph(+) cells. This assay should now enable investigators to unravel the mechanism(s) of IM resistance in stem cells. 相似文献
35.
Mary C. Gawlicki MBA Margaret C. Reilly MPH Ana Popielnicki BA Kate Reilly MA 《Value in health》2006,9(3):199-204
INTRODUCTION: There are no measures of health-related absenteeism and presenteeism validated for use in the large and increasing US Spanish-speaking population. Before using a Spanish translation of an available English-language questionnaire, the linguistic validity of the Spanish version must be established to ensure its conceptual equivalence to the original and its cultural appropriateness. OBJECTIVE: The objective of this study was to evaluate the linguistic validity of the US Spanish version of the Work Productivity and Activity Impairment questionnaire, General Health Version (WPAI:GH). METHODS: A US Spanish translation of the US English WPAI:GH was created through a reiterative process of creating harmonized forward and back translations by independent translators. Spanish-speaking and English-speaking subjects residing in the US self-administered the WPAI:GH in their primary language and were subsequently debriefed by a bilingual (Spanish-English) interviewer. RESULTS: US Spanish subjects (N = 31) and English subjects (N = 35), stratified equally by educational level, with and without a high school degree participated in the study. The WPAI-GH item comprehension rate was 98.6% for Spanish and 99.6% for English. Response revision rates during debriefing were 1.6% for Spanish and 0.5% for English. Responses to hypothetical scenarios indicated that both language versions adequately differentiate sick time taken for health and non-health reasons and between absenteeism and presenteeism. CONCLUSION: Linguistic validity of the US Spanish translation of the WPAI:GH was established among a diverse US Spanish-speaking population, including those with minimal education. 相似文献
36.
37.
This is the third and final part of a series of articles that report the findings of a study that investigated the effects of a summer externship program on the transition into a professional role among nurses who participated in a summer nurse externship program at an acute care pediatric hospital. Specifically, this article reports the retention and recruitment benefits of a summer nurse externship program for the institution from 1998 through 2003. A total of 153 externs out of the 193 (79.0%) assumed a registered nurse position at the institution, and 77% remained in that role for 12 months. Overall, the nurse extern program for this institution appeared to be an effective recruitment and retention strategy that is on par with the institution and national data for retention and turnover data. 相似文献
38.
Sally Urang Lorna Davis Charlotte Cram Elsberry Mary Kay Kozlowski 《Journal of Midwifery & Women's Health》1993,38(Z1):95s-99s
Fetal scalp blood sampling (FSBS), in conjunction with fetal heart rate monitoring, is a method of fetal surveillance that may avoid cesarean delivery of the healthy fetus or indicate the need for immediate delivery of a compromised fetus. Some researchers have recently begun to question the efficacy of FSBS. In this article, three nurse-midwives discuss FSBS as a tool in assessing fetal well-being during labor and consider whether FSBS is a nurse-midwifery procedure. 相似文献
39.
40.
Michael K. Gardner Elaine Clark Mary Ann C. Bowman Patrick J. Miller 《Alcoholism, clinical and experimental research》1989,13(4):508-511
This study investigated analogical reasoning abilities of alcoholics who had been abstinent from alcohol for at least 1 year. Their performance was compared to that of nonalcoholic controls matched as a group for education, age, and gender. Solution times and error rates were modeled using a regression model. Results showed a nonsignificant trend for alcoholics to be faster, but more error prone, than controls. The same componential model applied to both groups, and fit them equally well. Although differences have been found in analogical reasoning ability between controls and alcoholics immediately following detoxification, we find no evidence of differences after extended periods of sobriety. 相似文献