全文获取类型
收费全文 | 13822篇 |
免费 | 885篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 120篇 |
儿科学 | 313篇 |
妇产科学 | 240篇 |
基础医学 | 1916篇 |
口腔科学 | 271篇 |
临床医学 | 1701篇 |
内科学 | 2674篇 |
皮肤病学 | 83篇 |
神经病学 | 1413篇 |
特种医学 | 423篇 |
外科学 | 1728篇 |
综合类 | 168篇 |
一般理论 | 14篇 |
预防医学 | 1611篇 |
眼科学 | 247篇 |
药学 | 1043篇 |
中国医学 | 13篇 |
肿瘤学 | 757篇 |
出版年
2023年 | 81篇 |
2022年 | 121篇 |
2021年 | 263篇 |
2020年 | 193篇 |
2019年 | 252篇 |
2018年 | 325篇 |
2017年 | 247篇 |
2016年 | 251篇 |
2015年 | 320篇 |
2014年 | 417篇 |
2013年 | 621篇 |
2012年 | 994篇 |
2011年 | 1071篇 |
2010年 | 582篇 |
2009年 | 585篇 |
2008年 | 953篇 |
2007年 | 993篇 |
2006年 | 985篇 |
2005年 | 978篇 |
2004年 | 958篇 |
2003年 | 831篇 |
2002年 | 825篇 |
2001年 | 182篇 |
2000年 | 151篇 |
1999年 | 151篇 |
1998年 | 161篇 |
1997年 | 140篇 |
1996年 | 99篇 |
1995年 | 77篇 |
1994年 | 69篇 |
1993年 | 70篇 |
1992年 | 78篇 |
1991年 | 64篇 |
1990年 | 54篇 |
1989年 | 72篇 |
1988年 | 45篇 |
1987年 | 49篇 |
1986年 | 42篇 |
1985年 | 47篇 |
1984年 | 48篇 |
1983年 | 42篇 |
1982年 | 30篇 |
1981年 | 30篇 |
1980年 | 21篇 |
1979年 | 25篇 |
1978年 | 17篇 |
1977年 | 12篇 |
1976年 | 22篇 |
1975年 | 14篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
41.
Rebecca Setliff Janet E Porter Michael Malison Steve Frederick Thomas R Balderson 《JPHMP》2003,9(2):91-102
To address the need for management development in public health, the Centers for Disease Control and Prevention (CDC) established three independent workforce development initiatives aimed primarily at strengthening management and leadership capacity: the Sustainable Management Development Program, the Management Academy for Public Health, and the CDC Leadership and Management Institute. Though independently designed and implemented, the programs share similar guiding principles in their approach to management development: interactive (adult) learning, management tools that reinforce evidence-based decision making, individual feedback, continuous improvement of the learning process, posttraining support for networking and life-long learning, and teamwork. This article will discuss important lessons learned regarding best practices in management and leadership development. 相似文献
42.
Summary Prognostic factors define the study population, help formulate the study objectives, and influence the treatment strategies. They must be accounted for in the study analysis to obtain valid estimates of the treatment differences and to evaluate results across studies. The causal relationship between a prognostic factor and the study endpoint can only be established through prospective randomized study designs. Potential factors discovered through retrospective analysis must be verified to establish their validity. Using such factors prematurely to select patient population and treatment strategy for a new study will not establish the validity of the potentially important factor.Supported by NCI 5 PO1 CA53996-15 and NCI 5 U10 CA38926-08. 相似文献
43.
A device called the Dex Frame has recently been marketed as an aid for children with specific learning difficulties. Using a test of reading speed and a test of reading accuracy we have attempted to evaluate the device. Two groups of children with learning difficulties were used, one having sole use of the device and being allowed to carry it with them and a second group who only used the device when attending for remedial tuition and assessment. The results show that no significant improvement occurred in reading performance of the groups with learning difficulties using the Dex Frame as compared with a control group. The teachers of the groups did, however, feel that on an individual basis some children (< 10%) expressed that they felt more comfortable using the device. 相似文献
44.
Prospective assessment of biofeedback for the treatment of paradoxical puborectalis contraction 总被引:25,自引:18,他引:7
Steven D. Wexner M.D. John D. Cheape M.D. Jose M. N. Jorge M.D. Steve Heymen B.A. David G. Jagelman M.D. 《Diseases of the colon and rectum》1992,35(2):145-150
Eighteen patients with chronic constipation were diagnosed as having paradoxical puborectalis contraction (PPC) as the cause for their constipation. The diagnosis of PPC was made after office evaluation, colonic transit study, manometry, cinedefecography, and electromyography (EMG). These 18 patients had a mean duration of symptoms of 26.9 years; none of these patients had unassisted bowel movements. Fourteen patients had a mean of 4.6 laxative-induced bowel evacuations per week, and 11 patients had a mean of 4.4 enema-induced bowel evacuations per week. Patients underwent a mean of 8.9 one-hour EMG-based biofeedback sessions. At a mean follow-up of 9.1 (range, 0.5–12) months, these 18 patients had a mean of 7.3 unassisted bowel actions per week (
P
<0.0001). In addition, persistent laxative use was reported by only two patients, and, in both cases, this was once a week or less (
P
<0.001). Similarly, enema use was reported by only three patients, one once weekly and the other two thrice weekly (
P
<0.002). No biofeedback-related complications were identified. EMG-based biofeedback is a valuable technique associated with an 89 percent success rate in the treatment of PPC.Read at the meeting of The American Society of Colon and Rectal Surgeons, Boston, Massachusetts, May 12 to 17, 1991. 相似文献
45.
46.
This investigation used a derivation of acoustic reflection (AR) technology to make cross-sectional measurements of changes due to aging in the oral and pharyngeal lumina of male and female speakers. The purpose of the study was to establish preliminary normative data for such changes and to obtain acoustic measurements of changes due to aging in the formant frequencies of selected spoken vowels and their long-term average spectra (LTAS) analysis. Thirty-eight young men and women and 38 elderly men and women were involved in the study. The oral and pharyngeal lumina of the participants were measured with AR technology, and their formant frequencies were analyzed using the Kay Elemetrics Computerized Speech Lab. The findings have delineated specific and similar patterns of aging changes in human vocal tract configurations in speakers of both genders. Namely, the oral cavity length and volume of elderly speakers increased significantly compared to their young cohorts. The total vocal tract volume of elderly speakers also showed a significant increment, whereas the total vocal tract length of elderly speakers did not differ significantly from their young cohorts. Elderly speakers of both genders also showed similar patterns of acoustic changes of speech production, that is, consistent lowering of formant frequencies (especially F1) across selected vowel productions. Although new research models are still needed to succinctly account for the speech acoustic changes of the elderly, especially for their specific patterns of human vocal tract dimensional changes, this study has innovatively applied the noninvasive and cost-effective AR technology to monitor age-related human oral and pharyngeal lumina changes that have direct consequences for speech production. 相似文献
47.
48.
49.
50.
Petra Mullner Simon E.F. Spencer Daniel J. Wilson Geoff Jones Alasdair D. Noble Anne C. Midwinter Julie M. Collins-Emerson Philip Carter Steve Hathaway Nigel P. French 《Infection, genetics and evolution》2009,9(6):1311-1319
Integrated surveillance of infectious multi-source diseases using a combination of epidemiology, ecology, genetics and evolution can provide a valuable risk-based approach for the control of important human pathogens. This includes a better understanding of transmission routes and the impact of human activities on the emergence of zoonoses. Until recently New Zealand had extraordinarily high and increasing rates of notified human campylobacteriosis, and our limited understanding of the source of these infections was hindering efforts to control this disease. Genetic and epidemiological modeling of a 3-year dataset comprising multilocus sequence typed isolates from human clinical cases, coupled with concurrent data on food and environmental sources, enabled us to estimate the relative importance of different sources of human disease. Our studies provided evidence that poultry was the leading cause of human campylobacteriosis in New Zealand, causing an estimated 58–76% of cases with widely varying contributions by individual poultry suppliers. These findings influenced national policy and, after the implementation of poultry industry-specific interventions, a dramatic decline in human notified cases was observed in 2008. The comparative-modeling and molecular sentinel surveillance approach proposed in this study provides new opportunities for the management of zoonotic diseases. 相似文献