全文获取类型
收费全文 | 20024篇 |
免费 | 1581篇 |
国内免费 | 368篇 |
专业分类
耳鼻咽喉 | 126篇 |
儿科学 | 627篇 |
妇产科学 | 343篇 |
基础医学 | 1651篇 |
口腔科学 | 663篇 |
临床医学 | 1780篇 |
内科学 | 2926篇 |
皮肤病学 | 217篇 |
神经病学 | 1679篇 |
特种医学 | 1506篇 |
外科学 | 1978篇 |
综合类 | 1475篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 3492篇 |
眼科学 | 231篇 |
药学 | 1448篇 |
4篇 | |
中国医学 | 245篇 |
肿瘤学 | 1579篇 |
出版年
2024年 | 54篇 |
2023年 | 323篇 |
2022年 | 435篇 |
2021年 | 650篇 |
2020年 | 739篇 |
2019年 | 740篇 |
2018年 | 658篇 |
2017年 | 716篇 |
2016年 | 713篇 |
2015年 | 638篇 |
2014年 | 1196篇 |
2013年 | 1432篇 |
2012年 | 1090篇 |
2011年 | 1177篇 |
2010年 | 878篇 |
2009年 | 922篇 |
2008年 | 907篇 |
2007年 | 982篇 |
2006年 | 866篇 |
2005年 | 880篇 |
2004年 | 770篇 |
2003年 | 723篇 |
2002年 | 570篇 |
2001年 | 438篇 |
2000年 | 366篇 |
1999年 | 326篇 |
1998年 | 294篇 |
1997年 | 223篇 |
1996年 | 191篇 |
1995年 | 221篇 |
1994年 | 211篇 |
1993年 | 184篇 |
1992年 | 208篇 |
1991年 | 167篇 |
1990年 | 110篇 |
1989年 | 108篇 |
1988年 | 122篇 |
1987年 | 91篇 |
1986年 | 80篇 |
1985年 | 116篇 |
1984年 | 80篇 |
1983年 | 59篇 |
1982年 | 71篇 |
1981年 | 53篇 |
1980年 | 46篇 |
1979年 | 26篇 |
1978年 | 39篇 |
1977年 | 32篇 |
1976年 | 15篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
David L. Nordstrom Peter M. Layde Kurt A. Olson Dean Stueland Marilyn A. Follen Laura Brand 《American journal of industrial medicine》1996,29(5):509-515
We assessed risk factors for fall-related farm injuries in a population-based, case-control study. Cases had to reside in a defined geographic region served by a single medical center. Multiple sources reported cases, and a special farm census enabled random selection of controls. The annual risk of farm fall injury was 7.5 (95% CI: 5.7, 10.0) per 1,000 person-years. The crude incidence rate was higher in men, while the rate based on hours of farmwork was higher in women. In a multivariate analysis of risk factors, three factors were significantly associated with the risk. The risk of fall injury increased 2% (95% CI: 1%, 4%) per hour worked. Residents of farms with some farm workers not living on the farm had a fall injury rate 2.5 (95% CI: 1.0, 6.2) times greater than residents of other farms. Residents of farms with registered cows had one-third (95% CI: 0.14, 0.93) the risk of residents of other farms. To identify environmental hazards for fall injuries, researchers from several disciplines may need to collaborate in the design and conduct of studies that include injury site investigations. © 1996 Wiley-Liss, Inc. 相似文献
992.
993.
In contrast to amphibole forms of asbestos, chrysotile asbestos is often claimed to be only a minor cause of malignant pleural mesothelioma, a highly fatal cancer of the lining of the thoracic cavity. In this article we examine the evidence from animal and human studies that relates to this issue. Reported data do not support widely quoted views regarding the relative inertness of chrysotile fibers in mesothelioma causation. In fact, examination of all pertinent studies makes it clear that chrysotile asbestos is similar in potency to amphibole asbestos. Since asbestos is the major cause of mesothelioma, and chrysotile constitutes 95% of all asbestos use world wide, it can be concluded that chrysotile asbestos is the main cause of pleural mesothelioma in humans. © 1996 Wiley-Liss, Inc. 相似文献
994.
Peter Szatmari Marshall B. Jones Jeannette Holden Susan Bryson William Mahoney Larry Tuff Joanna MacLean Bradley White Giampiero Bartolucci Chris Schutz Paula Robinson Lorraine Hoult 《American journal of medical genetics. Part A》1996,67(4):354-360
The objective of this study was to examine familial factors influencing clinical variation in sibships that contained at least 2 children affected with autism or another form of pervasive developmental disorder (PDD). The sample included a total of 60 families, 23 with multiple cases of PDD and 37 with a single affected child. Measurements of IQ, adaptive behaviors in socialization and communication, and autistic symptoms were taken on all affected children. A high intraclass correlation, especially on IQ and an index of social behaviors, was observed between affected children from the same family. In contrast, low correlations were observed on measurements of IQ and adaptive behavior between affected and unaffected children from the same family. These data indicate that variation in severity of PDD is influenced by familial, and probably genetic, mechanisms. The results are discussed in relation to current theories on the genetics of autism and the heritable mechanisms underlying variations in clinical severity. © 1996 Wiley-Liss, Inc. 相似文献
995.
Kimmo K. Talvensaari Mikael Knip Peter Lanning Marjatta Lanning 《Pediatric blood & cancer》1996,26(3):166-172
We evaluated clinical characteristics and growth in 51 (24 males) long-term survivors of childhood cancer (median follow up 12.7 years). Patients were shorter, had a higher proportion of body fat and higher systolic blood pressure than their controls. The change in relative height during treatment was −0.83 standard deviation score (S.D.S.) in patients with cranial irradiation and −0.32 S.D.S. in patients without cranial irradiation; the figures after treatment were −0.56 and 0.20 S.D.S., respectively. Half (r2 = 0.50) of the variation in growth retardation during therapy could be explained by the cumulative doses of 6-mercaptopurine (6-MP) and vincristine and relative height at diagnosis. Cranial irradiation, increased relative height at diagnosis and young age at diagnosis were significant predictors of growth failure over the total observation period, explaining 43% of the variation. We conclude that long-term survivors of childhood cancer have impaired linear growth, increased body fat mass and elevated systolic blood pressure. Young children who are tall for their age at diagnosis and treated with cranial irradiation have the highest risk of impaired growth after the diagnosis. High doses of 6-MP seem to contribute significantly to growth retardation during therapy. © 1996 Wiley-Liss, Inc. 相似文献
996.
Victoria M. Lafontaine F.M. Ducharme Robert T. Brouillette 《Pediatric pulmonology》1996,21(2):121-131
Although pulse oximetry has been used to determine the frequency and extent of hemoglobin desaturation during sleep, movement artifact can result in overestimation of desaturation unless valid desaturations can be identified accurately. Therefore, we determined the accuracy of pulmonologists' and technicians' interpretations of graphic displays of desaturation events, derived an objective method for interpreting such events, and validated the method on an independent data set. Eighty-seven randomly selected desaturation events were classified as valid (58) or artifactual (29) based on cardiorespiratory recordings (gold standard) that included pulse waveform and respiratory inductive plethysmography signals. Using oximetry recordings (test method), nine pediatric pulmonologists and three respiratory technicians (“readers”) averaged 50 ± 11% (SD) accuracy for event classification. A single variable, the pulse amplitude modulation range (PAMR) prior to desaturation, performed better in discriminating valid from artifactual events with 76% accuracy (P < 0.05). Following a seminar on oximetry and the use of the PAMR method, the readers' accuracy increased to 73 ± 2%. In an independent set of 73 apparent desaturation events (74% valid, 26% artifactual), the PAMR method of assessing oximetry graphs yielded 82% accuracy; transcutaneous oxygen tension records confirmed a drop in oxygenation during 49 of 54 (89%) valid desaturation events. In conclusion, the most accurate method (91%) of assessing desaturation events requires recording of the pulse and respiratory waveforms. However, a practical, easy-to-use method of interpreting pulse oximetry recordings achieved 76–82% accuracy, which constitutes a significant improvement from previous subjective interpretations. Pediatr Pulmonol. 1996; 21:121–131. © 1996 Wiley-Liss, Inc. 相似文献
997.
Julianne Byrne Armando Cama Marie Reilly Mariantonietta Vigliarolo Laura Levato Luca Boni Natale Lavia Luciano Andreussi 《American journal of medical genetics. Part A》1996,66(3):303-310
Periconceptional vitamin supplementation with folate prevents about three-quarters of expected cases of neural tube defects (NTDs) in clinical trials. However, vitamin action may be regulated at the level of the gene, and individual susceptibility to environmental agents, including dietary components, also may be under genetic control. We investigated the presence of familial factors in a retrospective case control study of neural tube defects in Genoa, Italy. Cases included all patients treated at a single pediatric neurosurgical service. Controls matched on age and sex came from the same hospital. We found strong evidence for the contribution of genetic factors in this study. There was an excess risk of 14 for the occurrence of NTDs in first-degree relatives compared to controls (P < .0005). There was no difference in sex ratio in any group of relatives, but maternal grandparents of children with a high spinal lesion had 14% fewer offspring than paternal grandparents (P < .005), possibly because of excess miscarriages. Our study is the first to show complex patterns of inheritance in spina bifida families affecting three generations in one clinical subgroup and preferentially on the mother's side. These results support a role for genomic imprinting and highlight the value of multidisciplinary epidemiologic and clinical studies that include multiple generations. New studies incorporating dietary and genetic approaches will help clarify and extend these findings. © 1996 Wiley-Liss, Inc. 相似文献
998.
Naomi J. Weinshenker Idell Goldenberg Malcolm P. Rogers Robert M. Goisman Meredith G. Warshaw Eugene J. Fierman Russell G. Vasile Martin B. Keller 《Depression and anxiety》1996,4(5):209-216
This study examines a large cohort of subjects with social phobia, as part of a larger naturalistic and longitudinal study of 711 subjects with anxiety disorders. We focused on 176 subjects who were in an episode of social phobia at intake. We were particularly interested in evaluating the diagnostic distinction between generalized and specific social phobia. We compared these two groups along demographic characteristics, comorbidities, psychosocial functioning (health, role functioning, social functioning, and emotional functioning) and global assessment scores. We found that generalized social phobics tended to have an earlier age of onset as compared to the specific group; however, this is not a statistically significant difference at this level of analysis. The two groups did not differ for the current comorbidities examined. We observed no differences in the treatment received by the two types of social phobia subjects, and the two groups functioned equally well in terms of health and fulfilling social roles. In addition, we examined adverse childhood events (i.e., death of a parent, childhood abuse) and found no evidence for any differential impact these events might have on the type of social phobia. Although we did observe significantly greater fear of public speaking among the specific compared to the generalized group, which may indicate a qualitative difference between the subtypes, our results suggest that for most parameters, generalized and specific social phobia represent a continuum of similar and overlapping entities. Depression and Anxiety 4:209–216, 1996/1997.© 1997 Wiley-Liss, Inc. 相似文献
999.
王永炎 《北京中医药大学学报》2021,44(1):5-8
《中华人民共和国中医药法》体现了从团结中西医转轨为中西医并重的国策.习近平总书记称誉中医药是国之瑰宝,蕴育深邃的哲理,"传承精华、守正创新"为构建具有中国特色的、统一的医药学创造了良好的机遇. 相似文献
1000.