全文获取类型
收费全文 | 146295篇 |
免费 | 10597篇 |
国内免费 | 663篇 |
专业分类
耳鼻咽喉 | 1865篇 |
儿科学 | 3692篇 |
妇产科学 | 2593篇 |
基础医学 | 18643篇 |
口腔科学 | 3101篇 |
临床医学 | 14411篇 |
内科学 | 30031篇 |
皮肤病学 | 1903篇 |
神经病学 | 13316篇 |
特种医学 | 5719篇 |
外科学 | 23122篇 |
综合类 | 2163篇 |
现状与发展 | 1篇 |
一般理论 | 176篇 |
预防医学 | 13440篇 |
眼科学 | 3140篇 |
药学 | 10442篇 |
2篇 | |
中国医学 | 184篇 |
肿瘤学 | 9611篇 |
出版年
2023年 | 639篇 |
2022年 | 934篇 |
2021年 | 2682篇 |
2020年 | 1560篇 |
2019年 | 2537篇 |
2018年 | 3088篇 |
2017年 | 2236篇 |
2016年 | 2372篇 |
2015年 | 2881篇 |
2014年 | 4239篇 |
2013年 | 6466篇 |
2012年 | 9406篇 |
2011年 | 10004篇 |
2010年 | 5565篇 |
2009年 | 5076篇 |
2008年 | 8859篇 |
2007年 | 9568篇 |
2006年 | 9070篇 |
2005年 | 9277篇 |
2004年 | 8928篇 |
2003年 | 8395篇 |
2002年 | 8147篇 |
2001年 | 1496篇 |
2000年 | 1287篇 |
1999年 | 1607篇 |
1998年 | 1773篇 |
1997年 | 1420篇 |
1996年 | 1367篇 |
1995年 | 1323篇 |
1994年 | 1125篇 |
1993年 | 1103篇 |
1992年 | 1033篇 |
1991年 | 1047篇 |
1990年 | 916篇 |
1989年 | 878篇 |
1988年 | 904篇 |
1987年 | 896篇 |
1986年 | 904篇 |
1985年 | 994篇 |
1984年 | 1080篇 |
1983年 | 1017篇 |
1982年 | 1275篇 |
1981年 | 1291篇 |
1980年 | 1077篇 |
1979年 | 745篇 |
1978年 | 806篇 |
1977年 | 696篇 |
1976年 | 624篇 |
1975年 | 574篇 |
1974年 | 562篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
61.
Daoyan Wei Henry Q. Xiong James L. Abbruzzese Keping Xie 《Journal of gastrointestinal cancer》2003,33(1):43-60
Pancreatic cancer is a lethal disease characterized by early metastasis, local invasion, and resistance to conventional therapies. To understand its etiology and eventually make prevention of it possible and effective, appropriate carcinogenesis models will certainly help us understand the effects of environmental and genetic elements on pancreatic carcinogenesis. The development of new treatment strategies to control cancer metastasis is of immediate urgency. Fulfillment of this task relies on our knowledge of the cellular and molecular biology of pancreatic cancer metastasis and the availability of biologically and clinically relevant model systems. Many of the existing pancreatic cancer carcinogenesis and metastasis animal models are described in this review. The advantages and disadvantages of each model and their clinical implications are discussed, and special attention is focused on experimental therapeutic strategies targeting pancreatic cancer metastasis. 相似文献
62.
63.
Turboprop: improved PROPELLER imaging. 总被引:1,自引:0,他引:1
A variant of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) MRI, called turboprop, is introduced. This method employs an oscillating readout gradient during each spin echo of the echo train to collect more lines of data per echo train, which reduces the minimum scan time, motion-related artifact, and specific absorption rate (SAR) while increasing sampling efficiency. It can be applied to conventional fast spin-echo (FSE) imaging; however, this article emphasizes its application in diffusion-weighted imaging (DWI). The method is described and compared with conventional PROPELLER imaging, and clinical images collected with this PROPELLER variant are shown. 相似文献
64.
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
65.
Christine E. East Fung Yee Chan Shaun P. Brennecke James F. King Paul B. Colditz 《分娩》2006,33(2):101-109
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006) 相似文献
66.
67.
68.
Harvey A. Siegal PhD ; Paul J. Draus PhD ; Robert G. Carlson PhD ; Russel S. Falck MA ; Jichuan Wang PhD 《The Journal of rural health》2006,22(2):169-173
CONTEXT: Although the nonmedical use of stimulant drugs such as cocaine and methamphetamine is increasingly common in many rural areas of the United States, little is known about the health beliefs of people who use these drugs. PURPOSE: This research describes illicit stimulant drug users' views on health and health-related concepts that may affect their utilization of health care services. METHODS: A respondent-driven sampling plan was used to recruit 249 not-in-treatment, nonmedical stimulant drug users who were residing in 3 rural counties in west central Ohio. A structured questionnaire administered by trained interviewers was used to collect information on a range of topics, including current drug use, self-reported health status, perceived need for substance abuse treatment, and beliefs about health and health services. FINDINGS: Participants reported using a wide variety of drugs nonmedically, some by injection. Alcohol and marijuana were the most commonly used drugs in the 30 days prior to the interview. Powder cocaine was used by 72.3% of the sample, crack by 68.3%, and methamphetamine by 29.7%. Fair or poor health status was reported by 41.3% of the participants. Only 20.9% of the sample felt they needed drug abuse treatment. Less than one third of the sample reported that they would feel comfortable talking to a physician about their drug use, and 65.1% said they preferred taking care of their problems without getting professional help. CONCLUSIONS: Stimulant drug users in rural Ohio are involved with a range of substances and hold health beliefs that may impede health services utilization. 相似文献
69.
We report on 4 children who experienced a syncopal episode while being treated with guanfacine without any other evident cause. Syncope appears to be an uncommon side effect of guanfacine and is probably due to drug-induced hypotension or bradycardia. 相似文献
70.
Brief review: History, concept and controversies in the neurological determination of death 总被引:1,自引:0,他引:1
Leonard Baron Sam D. Shemie Jeannie Teitelbaum Christopher James Doig 《Journal canadien d'anesthésie》2006,53(6):602-608
PURPOSE: Despite general worldwide acceptance of the concept of neurological determination of death (NDD), inconsistencies in clinical criteria and ancillary testing requirements remain. Numerous guidelines for NDD may be applied in clinical practice by a variety of medical practitioners, but the scientific rationale for specific guideline recommendations often remains unclear. This review examines the evolution of NDD, and seeks to provide scientific validation for existing NDD criteria. SOURCE: English language peer-reviewed medical journals and established contemporary medical texts. PRINCIPAL FINDINGS: Currently published guidelines appear to have evolved from the work of the ad hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death. The Conference of the Royal Colleges and Faculties of the United Kingdom refined the criteria and subsequently adopted the principal of brainstem death. While the fundamentals of NDD guidelines are remarkably consistent worldwide, specific criteria and requirements are often inconsistent. CONCLUSION: Numerous controversies regarding NDD continue to exist, necessitating further scientific clarification of these issues. More recently published guidelines representing the collective opinion of world experts in NDD based upon best current scientific evidence are available in current medical journals. 相似文献