全文获取类型
收费全文 | 50401篇 |
免费 | 3415篇 |
国内免费 | 105篇 |
专业分类
耳鼻咽喉 | 386篇 |
儿科学 | 1887篇 |
妇产科学 | 1789篇 |
基础医学 | 6006篇 |
口腔科学 | 596篇 |
临床医学 | 8799篇 |
内科学 | 9173篇 |
皮肤病学 | 755篇 |
神经病学 | 4550篇 |
特种医学 | 882篇 |
外国民族医学 | 33篇 |
外科学 | 4400篇 |
综合类 | 615篇 |
一般理论 | 79篇 |
预防医学 | 7087篇 |
眼科学 | 539篇 |
药学 | 2806篇 |
1篇 | |
中国医学 | 89篇 |
肿瘤学 | 3449篇 |
出版年
2023年 | 300篇 |
2022年 | 433篇 |
2021年 | 987篇 |
2020年 | 662篇 |
2019年 | 1073篇 |
2018年 | 1221篇 |
2017年 | 844篇 |
2016年 | 963篇 |
2015年 | 1044篇 |
2014年 | 1430篇 |
2013年 | 2404篇 |
2012年 | 3430篇 |
2011年 | 3676篇 |
2010年 | 1957篇 |
2009年 | 1836篇 |
2008年 | 3243篇 |
2007年 | 3703篇 |
2006年 | 3561篇 |
2005年 | 3459篇 |
2004年 | 3343篇 |
2003年 | 3188篇 |
2002年 | 2996篇 |
2001年 | 392篇 |
2000年 | 277篇 |
1999年 | 399篇 |
1998年 | 650篇 |
1997年 | 516篇 |
1996年 | 446篇 |
1995年 | 366篇 |
1994年 | 369篇 |
1993年 | 366篇 |
1992年 | 260篇 |
1991年 | 229篇 |
1990年 | 222篇 |
1989年 | 174篇 |
1988年 | 178篇 |
1987年 | 187篇 |
1986年 | 158篇 |
1985年 | 185篇 |
1984年 | 209篇 |
1983年 | 212篇 |
1982年 | 268篇 |
1981年 | 246篇 |
1980年 | 193篇 |
1979年 | 134篇 |
1978年 | 114篇 |
1977年 | 133篇 |
1976年 | 112篇 |
1975年 | 93篇 |
1973年 | 87篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
71.
72.
73.
Petra Thurmüller Maria Troulis Mary Jane O'Neill Leonard B Kaban 《Journal of oral and maxillofacial surgery》2002,60(9):1038-1044
PURPOSE: A standardized, noninvasive technique to assess healing of the mandibular distraction wound is not available. Current methods include clinical examination, plain radiography, and computed tomography. These imaging techniques are expensive and obligate the patient to serial radiation exposure. In addition, anatomic overlap and metal artifacts may obscure the distraction gap. In contrast, ultrasound has been shown to be a noninvasive, efficient, and inexpensive way to evaluate bone healing. The purpose of this study was to test the feasibility of ultrasound to evaluate an experimental mandibular distraction osteogenesis wound. MATERIALS AND METHODS: Distraction devices were placed via a submandibular incision into 24 minipigs. The protocol consisted of 0-day latency and distraction rates of 1, 2, or 4 mm/d for a 12-mm gap. The wounds were assessed in vivo after 0, 8, 16, and 24 days of neutral fixation. Ex vivo radiographs were used to estimate bone fill using a semiquantitative score. A semiquantitative ultrasound score was assigned, and the beam penetration depth was measured in millimeters. RESULTS: In all groups, clinical stability of the distraction wound increased with the duration of fixation. Plain radiographs, taken during neutral fixation, showed that the desired distraction gap was achieved and maintained. The ultrasound score increased with fixation time, whereas beam penetration depth decreased as expected. Ex vivo radiographs showed increasing bone fill score with time and paralleled the ultrasound score. CONCLUSIONS: The results of this feasibility study indicate that ultrasound is potentially useful for the assessment of bone formation in distraction osteogenesis wounds. 相似文献
74.
Kate Windridge Carolyn Tarrant George K Freeman Richard Baker Mary Boulton Janet Low 《The British journal of general practice》2004,54(502):364-366
We report an analysis of the qualitative phase of a study of patients' and carers' views of primary care services, focusing on their experiences of access to face-to-face general practitioner (GP) consultations during the period when new access policies were being implemented. Practices interpreted the new policy in various ways; restricted interpretations, including restriction of access to telephone booking, could cause distress to patients. Patients and carers welcomed flexible interpretations of the policy that offered choice, such as a choice of GP, or of booking in advance. 相似文献
75.
Barry D Anderson Peter C Adamson Susan L Weiner Mary S McCabe Malcolm A Smith 《Journal of clinical oncology》2004,22(23):4846-4850
Federal regulations prescribe distinct protections for children participating in research studies. Procedures for collecting tissue specimens from children solely for research purposes must pose no more than a minor increase over minimum risk, thereby limiting the approvable correlative biologic studies to evaluate molecularly targeted agents in children with cancer. Ethical issues arise when approvable correlative studies are a mandatory component of an early-phase pediatric clinical trial of new anticancer agents. The National Cancer Institute Cancer Therapy Evaluation Program sponsored a workshop in 2002 to discuss tissue collection for correlative biologic studies in early-phase childhood cancer clinical studies of molecularly targeted agents. Workshop participants recommended the following: (1) tissue specimens for correlative studies should provide vital clinical and scientific results to qualify for early-phase pediatric study consideration; (2) parents should receive a realistic appraisal of the risks, requirements, and potential for benefit of phase I protocol participation; (3) investigators should clearly distinguish clinically necessary procedures from research procedures of no benefit to the child to improve correlative study informed consent; and (4) participation in correlative research studies included in clinical trials generally should be voluntary. The need to acquire important biologic data regarding new molecular agents will challenge the ingenuity of pediatric cancer researchers, necessitating the application of highly sensitive laboratory assay methods, new imaging procedures, and preclinical models of childhood cancer. Such innovative methods can allow necessary scientific information to be obtained while simultaneously respecting the protections appropriately afforded to children participating in research studies and minimizing the burden of research participation for children with cancer and their families. 相似文献
76.
77.
Mary E. Van Bourgondien Lee M. Marcus Eric Schopler 《Journal of autism and developmental disorders》1992,22(4):493-506
The purpose of this study was to clarify the issue of whether DSM-III-R (American Psychological Association [APA], 1987) over-or underdiagnoses autism by comparing this diagnostic system to a well-established objective measure of diagnosis, the Childhood Autism Rating Scale (CARS). A secondary goal was to determine which of the 16 criteria are the best discriminators of autism. DSM-III-R, CARS, and clinical diagnoses of 138 consecutive admissions to a statewide program for the diagnosis and treatment of autistic and related communication-handicapped individuals (Division TEACCH in North Carolina) were compared. Results indicated a generally high degree of agreement on the diagnosis of autism using the three systems. Within this tratment-oriented program, the CARS and clinical ratings diagnosed a greater number of cases as autistic than did the DSM-III-R criteria, suggesting that DSM-III-R slightly underdiagnosed autism. The criteria that most strongly related to the diagnosis of autism regardless of the system were lack of awareness of others, abnormal social play, an impaired ability to make friends, abnormal nonverbal communication, stereotypic body movements, and restricted range of interests. 相似文献
78.
Kristen H. Kjerulff Barbara Pillar Mary Etta Mills Judy Lanigan 《Journal of medical systems》1992,16(1):7-13
Technology anxiety, defined as a fear of working with medical equipment, was measured via the use of the Technology Response Questionnaire. Nurses (N=414) working on nine types of nursing units at two hospitals participated in the study. Nurses working on psychiatric units were found to be most anxious about working with medical equipment, while nurses working on surgical and adult intensive care units were least anxious. A comparison of the nurses who were highest and lowest on technology anxiety indicated that those who were most anxious about technology were less positive toward computers, felt more stressed by their work, were lower on job satisfaction, less positive toward the physicians they worked with, lower on personality scales of autonomy and adaptability, were less likely to do care planning regularly or to use nursing diagnoses, and tended to be older than less anxious nurses. 相似文献
79.