全文获取类型
收费全文 | 46558篇 |
免费 | 3478篇 |
国内免费 | 188篇 |
专业分类
耳鼻咽喉 | 375篇 |
儿科学 | 1506篇 |
妇产科学 | 1200篇 |
基础医学 | 6585篇 |
口腔科学 | 590篇 |
临床医学 | 5031篇 |
内科学 | 9730篇 |
皮肤病学 | 876篇 |
神经病学 | 5540篇 |
特种医学 | 1122篇 |
外科学 | 4149篇 |
综合类 | 380篇 |
一般理论 | 58篇 |
预防医学 | 5665篇 |
眼科学 | 616篇 |
药学 | 2974篇 |
中国医学 | 86篇 |
肿瘤学 | 3741篇 |
出版年
2024年 | 59篇 |
2023年 | 650篇 |
2022年 | 1086篇 |
2021年 | 2142篇 |
2020年 | 1297篇 |
2019年 | 1772篇 |
2018年 | 2036篇 |
2017年 | 1361篇 |
2016年 | 1515篇 |
2015年 | 1659篇 |
2014年 | 2024篇 |
2013年 | 2621篇 |
2012年 | 4194篇 |
2011年 | 4149篇 |
2010年 | 2103篇 |
2009年 | 1844篇 |
2008年 | 2942篇 |
2007年 | 2905篇 |
2006年 | 2773篇 |
2005年 | 2568篇 |
2004年 | 2277篇 |
2003年 | 2034篇 |
2002年 | 1731篇 |
2001年 | 193篇 |
2000年 | 142篇 |
1999年 | 208篇 |
1998年 | 347篇 |
1997年 | 260篇 |
1996年 | 212篇 |
1995年 | 175篇 |
1994年 | 124篇 |
1993年 | 118篇 |
1992年 | 68篇 |
1991年 | 65篇 |
1990年 | 55篇 |
1989年 | 56篇 |
1988年 | 49篇 |
1987年 | 37篇 |
1986年 | 38篇 |
1985年 | 34篇 |
1984年 | 46篇 |
1983年 | 44篇 |
1982年 | 33篇 |
1981年 | 41篇 |
1980年 | 28篇 |
1979年 | 17篇 |
1978年 | 13篇 |
1977年 | 20篇 |
1975年 | 9篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Frank L Cole Laura L Kuensting Susan Maclean Cynthia Abel Joyce Mickanin Patty Brueske Mary Ellen Wilson Maureen Rehwaldt 《Journal of emergency nursing》2002,28(5):414-419
INTRODUCTION: Very little is known about clinical nurse specialists and nurse practitioners (advance practice nurses [APNs]) who practice in emergency care settings. The Advanced Practice Committee of the ENA sought to determine a profile of these individuals. METHODS: Surveys were distributed to all registrants at 2 ENA conferences and posted on the ENA Web site. This survey asked 17 questions concerning the demographic characteristics of the APN respondents (eg, education, experience, certification, state recognition, and practice area). The survey was completed by 166 APNs. RESULTS: APNs had considerable experience as ED registered nurses before becoming an APN. They obtained their APN education at the master's degree or post-master's degree level. State recognition was required for 89.2% of the APNs. The majority of APNs (61.4%) obtained their certification through the American Nurses Credentialing Center. Nurse practitioners were predominantly family nurse practitioners (43%), and clinical nurse specialists were either critical care clinical nurse specialists (8.9%) or had other certifications (5.9%). APNs provided services in both the main emergency department and the fast track (45.7%) and were relatively new to their role as an APN. DISCUSSION: Consistent with current educational and certification requirements, the vast majority of APNs held a master's degree. Although relatively new to their role as APNs in emergency care, they were nonetheless very experienced as ED registered nurses. The majority of APNs were certified, even though that is not required for practice in all states. Continued research is needed to identify the most effective utilization of APNs, document their contributions to patient care outcomes, and develop strategies to meet their educational and practice needs. 相似文献
102.
Marjolein C. H. van der Meulen Robert Marcus Laura K. Bachrach Dennis R. Carter 《Journal of orthopaedic research》1997,15(3):473-476
We have developed an analytical model of long bone cross-sectional ontogeny in which appositional growth of the diaphysis is primarily driven by mechanical stimuli associated with increasing body mass during growth and development. In this study, our goal was to compare theoretical predictions of femoral diaphyseal structure from this model with measurements of femoral bone mineral and geometry by dual energy x-ray absorptiometry. Measurements of mid-diaphyseal femoral geometry and structure were made previously in 101 Caucasian adolescents and young adults 9–26 years of age. The data on measured bone mineral content and calculated section modulus were compared with the results of our analytical model of cross-sectional development of the human femur over the same age range. Both bone mineral content and section modulus showed good correspondence with experimental measurements when the relationships with age and body mass were examined. Strong linear relationships were evident for both parameters when examined as a function of body mass. 相似文献
103.
Robert L. Koegel Laura Schreibman Lauren M. Loos Hanne Dirlich-Wilhelm Glen Dunlap Frank R. Robbins Anthony J. Plienis 《Journal of autism and developmental disorders》1992,22(2):205-216
The present study extends the area of research on stress in parents of autistic children. In this study we used the Questionnaire on Resources and Stress (Holroyd, 1987) to compare the stress profiles across mothers (a) who lived in different cultural and geographic environments; (b) who had children of different ages; and (c) who had children with different functioning levels. Results showed a characteristic profile that was highly consistent across each of these subgroups. Major differences from the normative data occurred on scales measuring stress associated with dependency and management, cognitive impairment, limits on family opportunity, and life-span care. Results suggest the importance of developing treatment programs aimed at reducing stress in specific areas in families with autistic children.Orchard Mental Health CenterThis research was supported by U.S. Department of Education, NIDRR Cooperative Agreement No. G0087C0234 (Koegel and Dunlap), by U.S. Public Health Service Research Grants MH28210 (Koegel) and MH39434 (Schreibman) from the National Institute of Mental Health, by Grant No. G008530082 from the U.S. Department of Education, Handicapped Children's Early Education Program (Dunlap), and by Fogarty Senior International Fellowship 1 FOB TWO 1374-01 (Schreibman) from the Fogarty International Center of the National Institutes of Health. The authors acknowledge the contributions of Prof. Dr. med. Hedwig Amorosa, and Dorle Staniczek, Soz. Pad. of the Max Planck Institute for Psychiatry, Munich, West Germany, and express particular appreciation to Prof. Dr. med. D. Ploog, Director of the Institute. 相似文献
104.
105.
Alberto Falchetti Marco Di Stefano Francesca Marini Francesca Del Monte Carmelo Mavilia Debora Strigoli Maria L De Feo Giovan Isaia Laura Masi Antonietta Amedei Federica Cioppi Valentina Ghinoi Susanna Maddali Bongi Giuseppina Di Fede Carmela Sferrazza Giovan B Rini Daniela Melchiorre Marco Matucci-Cerinic Maria L Brandi 《Journal of bone and mineral research》2004,19(6):1013-1017
PDB is genetically heterogeneous. Mutations of the sequestosome1 gene have been reported in sporadic and familial forms of Paget's in patients of French Canadian and British descent. Mutational analyses in different ethnic groups are needed to accurately investigate hereditary diseases. We describe two novel mutations of sequestosome1 in 62 Italian sporadic patients, confirming the role of the encoded protein in this disorder. INTRODUCTION: Paget's disease of bone (PDB) is a relatively common disease of bone metabolism reported to affect up to 3% of whites over 55 years of age. The disorder is genetically heterogeneous, and at present, there is scientific evidence that at least eight different human chromosomal loci are correlated with its pathogenesis. Mutations of the sequestosome1 (SQSTM1) gene were identified as responsible for most of the sporadic and familial forms of Paget in patients of French Canadian and British descent. Such mutations were located at exon 7 and 8 levels, encoding for the ubiquitin protein-binding domain (UBA) and representing a mutational hot spot area. MATERIALS AND METHODS: To verify the involvement of this gene in Italian subjects affected by PDB, we performed mutational analysis in 62 sporadic PDB cases. RESULTS: We described three different mutations at exon 8 level: P392L, already described in the French Canadian population and families predominantly of British descendent, and two novel mutations consisting of the amino acid substitutions M404V and G425R. No significant differences in the clinical history of PDB have been observed in patients with SQSTM1 mutations in respect to those without. CONCLUSIONS: Even though our findings suggest a minor involvement of the SQSTM1 gene in the pathogenesis of sporadic Italian Paget's cases, the identification of different significant mutations within the SQSTM1 gene in unrelated, but clinically similar individuals, offers extremely convincing evidence for a causal relationship between this gene and PDB. Longitudinal studies are needed to assess the penetrance of genotype/phenotype correlations. Our findings confirm the evidence of a clustered mutation area at this level in this disorder. 相似文献
106.
107.
108.
A restricted field of view (rFOV) approach for imaging a dynamic time series of volumes of limited spatial extent within a larger subject is described. The shorter readout with rFOV-MRI can be exploited to either limit image artifacts or increase spatial resolution. To accomplish rFOV imaging of a multislice volume for a dynamic series, an outer volume suppression (OVS) preparation that saturates signal external to a cylinder through the subject is followed by slice-selective excitation and a spiral readout. The pass- and stopband efficiencies of the OVS in an agar gel phantom were 97% (+/-1.5%) and 3% (+/-1%), respectively. Profiles of the temporal signal-to-noise ratio (SNR) were measured in a phantom and an adult brain. The rFOV sequence reduced distortions from off-resonance signal and T2*-induced blurring compared to a conventional sequence. Sequence utility is demonstrated for high-resolution rFOV functional MRI (fMRI) in the visual cortex. The rFOV sequence may prove to be useful for other multislice dynamic and high-resolution imaging applications. 相似文献
109.
110.
A. C. Leon M. Katherine Shear Laura Portera G. L. Klerman 《Social psychiatry and psychiatric epidemiology》1992,27(2):78-82
Summary The DSM-III-R incorporates both distress (symptoms) and disability (impairment) in the definition of a psychiatric disorder. In psychiatric research there is a wide array of instruments used to measure symptom severity, but a limited selection for the assessment of impairment. The psychometric properties of one such instrument, The Sheehan Disability Scale (Sheehan 1983), are evaluated in this paper. The data analyzed come from two studies of patients with panic disorder, the Cross National Collaborative Panic Study-Phase I and the Panic Depression Study. In this report both the alpha coefficients and factor analyses indicate that the reliability of the scale is acceptable. The factor structure of the items and the sensitivity to change of their composite demonstrate satisfactory construct validity. The criterion-related validity is substantiated by the significant relationship between symptomatology and impairment. These analyses were limited to patients with panic disorder. Further work is needed to evaluate the instrument in assessing patients with other disorders. 相似文献