全文获取类型
收费全文 | 1654篇 |
免费 | 97篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 91篇 |
妇产科学 | 34篇 |
基础医学 | 177篇 |
口腔科学 | 35篇 |
临床医学 | 121篇 |
内科学 | 369篇 |
皮肤病学 | 10篇 |
神经病学 | 102篇 |
特种医学 | 164篇 |
外科学 | 240篇 |
综合类 | 49篇 |
一般理论 | 1篇 |
预防医学 | 65篇 |
眼科学 | 65篇 |
药学 | 139篇 |
中国医学 | 3篇 |
肿瘤学 | 98篇 |
出版年
2023年 | 11篇 |
2022年 | 12篇 |
2021年 | 41篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 42篇 |
2017年 | 21篇 |
2016年 | 29篇 |
2015年 | 27篇 |
2014年 | 54篇 |
2013年 | 61篇 |
2012年 | 95篇 |
2011年 | 108篇 |
2010年 | 62篇 |
2009年 | 53篇 |
2008年 | 81篇 |
2007年 | 110篇 |
2006年 | 73篇 |
2005年 | 64篇 |
2004年 | 66篇 |
2003年 | 60篇 |
2002年 | 43篇 |
2001年 | 46篇 |
2000年 | 59篇 |
1999年 | 39篇 |
1998年 | 22篇 |
1997年 | 16篇 |
1996年 | 13篇 |
1995年 | 12篇 |
1992年 | 16篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 27篇 |
1988年 | 26篇 |
1987年 | 13篇 |
1986年 | 23篇 |
1985年 | 17篇 |
1984年 | 22篇 |
1983年 | 16篇 |
1982年 | 11篇 |
1979年 | 23篇 |
1978年 | 18篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1974年 | 10篇 |
1973年 | 12篇 |
1972年 | 12篇 |
1970年 | 9篇 |
1968年 | 7篇 |
1966年 | 10篇 |
排序方式: 共有1779条查询结果,搜索用时 15 毫秒
61.
62.
Joseph Massad Russell Wicks Swati Ahuja David R. Cagna 《Journal of prosthodontics》2019,28(4):e912-e916
Full‐arch, fixed, implant‐supported prostheses can be designed to be cement‐ or screw‐retained. Both retention mechanisms have a few inherent disadvantages. A fixed attachment system has been introduced to circumvent the disadvantages of both screw and cement retention. This system eliminates the screw access holes and the use of cement. The number of intraoral procedures required is also reduced. The purpose of this article is to report a case using the Locator F‐Tx Attachment System to facilitate fabrication of an esthetic, clinician‐retrievable, full‐arch implant‐supported fixed dental prosthesis. 相似文献
63.
The effects of respiratory movements on the ultrasonic echoes of the cardiac structures were recorded and analyzed in 50 consecutive patients. Deep inspiration in cooperative patients resulted in a considerable increase of dense anterior echoes, with blotting out of any distal or posterior echoes in 12 of 44 patients (group A). In the second or larger series (32 of 44 patients; group B), a posterior displacement of most of the identifiable intrinsic cardiac echoes was seen with deep inspiration, particularly those of the posterior wall of the left ventricle. Forced expiration produced an opposite or anterior displacement of the cardiac echoes. Normal respirations showed similar but smaller excursions. 相似文献
64.
Clinical features and investigative findings in presence of mitral leaflet prolapse. Study of 85 consecutive patients. 下载免费PDF全文
In a 14-month period mitral leaflet prolapse was diagnosed in 85 patients by echocardiography or cineangiography. Chest pain alone was the presenting complaint in 30 patients and linked with palpitation, dyspnoea, or syncope in 9. Eleven presented with major neurological disturbances (9 had transient ischaemic attacks), 10 with palpitation, 4 with undue and persistent fatigue, 2 with dyspnoea, and 2 with dizziness. Seventeen were referred not because of symptoms but because of clicks and murmurs. Overall, chest pain affected 61 patients and unless associated with coronary artery disease was not anginal. Palpitation was admitted by 42 patients; dizziness, lightheadedness, or paraesthesiae by 15, and syncope by 12. Systolic auscultatory abnormalities were noted in 69: 25 had single clicks, 3 had multiple clicks, 19 had both click(s) and murmur, and 22 had a murmur alone. Electrocardiography revealed ST segments flat for greater than 0-10 s in 21, prolonged QTc in 18, and T wave flattening or inversion in inferior limb and lateral chest leads in 14. The exercise stress test was abnormal in 13 of 27 patients. Mitral valve echograms showed definite mitral leaflet prolapse in 61, 'possible' prolapse in 14, and were normal in 8 patients with angiographic proof of mitral leaflet prolapse. Cardiac catheterization with left ventriculography showed prolapse of posterior mitral leaflet in 36, of both leaflets in 2, and left ventricular wall motion abnormalities in 16 cases. Selective coronary arteriography in 31 cases showed major vessel narrowing of larger than or equal to 80 per cent lumen diameter in 4, all with angina. This consecutive series indicates that the physical event of mitral leaflet prolapse is more common than hitherto appreciated, is priminently associated with non-anginal chest pain, palpitation, and neurological disturbances, and in 90 per cent of cases could be shown echocardiographically. 相似文献
65.
Defeng Wang Lin Shi Yi‐Xiang J. Wang Jing Yuan David K.W. Yeung Ann D. King Anil T. Ahuja Pheng Ann Heng 《Magnetic resonance in medicine》2010,63(5):1431-1436
Most traditional methods for T1 map estimation in MRI with fast low‐angle‐shot sequences are aimed at high efficiency by compromising the fitting accuracy. In this paper, the fundamental problem of parameter estimation in fast low‐angle‐shot MRI was re‐examined, and an accurate and fast optimization approach, named concatenated optimization for parameter estimation, was proposed for the regression of data points acquired with multiple flip angles. The initial estimation of T1 was obtained from the linear regression, followed by the constrained nonlinear regression based on the initial estimates. This heterogeneous initialization strategy improves the fitting accuracy and reduces the computational time. A computationally efficient implementation of concatenated optimization for parameter estimation was achieved based on the graphic processing unit, named as concatenated optimization for parameter estimation graphic processing unit. In experimental comparison with Fram's method and the Fitter Tool in Jim, the proposed methods are capable of achieving significantly higher efficiency and more accurate estimations. Magn Reson Med 63:1431–1436, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
66.
In this paper, we present the first-ever experimental Compton line shapes of HgBr2 and HgI2 using 137Cs Compton spectrometer. To compare our experimental momentum densities, we have computed the Compton profiles using Hartree–Fock and density functional theory within linear combination of atomic orbitals. We have also computed the energy bands and density of states using the linear combination of atomic orbitals and full potential linearized augmented plane wave method. On the basis of equal-valence-electron-density profiles, it is seen that HgI2 is more covalent than HgBr2 which is in agreement with the valence charge densities. The experimental isotropic profiles are found to be relatively in better agreement with the Hartree–Fock data. We have also discussed the photoluminescence and detection properties of both the halides. 相似文献
67.
Syed Ifthekar Kaustubh Ahuja Samarth Mittal Bhaskar Sarkar Gagan Deep Watson Thomas Pankaj Kandwal 《Indian Journal of Orthopaedics》2021,55(3):673
BackgroundInjuries involving upper cervical spine are serious and fatal injuries which are associated with alteration of normal occipital–cervical anatomy. These injuries may result in permanent neurologic deficits or neck deformity if not treated in a timely and appropriate manner.ObjectiveTo evaluate the outcomes of neglected upper cervical spine injuries treated by various methods.Study designRetrospective study.Materials and methodsTwelve patients attending ER or OPD with a history of neck trauma and who were diagnosed with fractures and fracture dislocations C1 and C2 were included in the study. Fresh injuries sustained within a week were excluded from study. The outcomes were measured in terms of improvement in VAS, ODI Scores and correction of the neck deformity. Surgical parameters like duration of surgery and blood loss were also observed.ResultsEleven males and one female. The mean age was 40.9 ± 16.9 (07–67 years). Eleven patients underwent posterior instrumentation, while one patient was treated anteriorly. The mean delay in presentation was 28 ± 8.67 days (15–42 days). The mean duration of surgery was 188.3 ± 34.35 min (120–240 min), average blood loss was 350 ± 111.8 ml (150–600 ml). The mean VAS improved from 8.45 ± 0.89 to 3.9 ± 0.51 (p < 0.05). The mean ODI Pre-operatively was 88.45 ± 5.89 which improved to 31.9 ± 4.01 (p < 0.05). The neck deformity/torticollis was corrected in all the patients.ConclusionsNeglected upper cervical spine injuries are difficult to treat and a posterior approach is helpful in reducing the subluxations indirectly and to obtain a posterior fusion. 相似文献
68.
S. Ghatak A. Singha A. Sen C. Guha A. Ahuja U. Bhattacharjee S. Das N. R. Pradhan K. Puro C. Jana T. K. Dey K. L. Prashantkumar A. Das I. Shakuntala U. Biswas P. S. Jana 《Transboundary and Emerging Diseases》2013,60(5):385-389
In this study, eight Escherichia coli isolates were obtained from milk samples of dairy cattle suffering from clinical/subclinical mastitis. Isolates were characterized for antimicrobial resistance traits and virulence genes. Results revealed that one isolate was harbouring New Delhi metallo‐beta‐lactamase gene (blaNDM). Cloning and sequencing of the PCR amplicon confirmed the identity of the gene (GenBank accession no. KC769583 ) having 100% homology with blaNDM‐5 (GenBank accession no. JN104597.1 ), and this isolate was susceptible to colistin, chloramphenicol and tetracycline only. Moreover, another isolate carried extended‐spectrum beta‐lactamase (ESBL) gene – blaCTX‐M, and all isolates possessed blaTEM gene. Of the eight isolates, only one isolate was positive for shiga toxin gene (stx2), and none were harbouring stx1 gene. Occurrence of New Delhi metallo‐beta‐lactamase (blaNDM) in one E. coli isolate and ESBL genes in other isolates poses a potential threat to human health following possible entry and spread through food chain. 相似文献
69.
70.
Jin He Barish H. Edil John L. Cameron Richard D. Schulick Ralph H. Hruban Joseph M. Herman Lei Zheng Christine Iacobuzio-Donahue Nita Ahuja Timothy M. Pawlik Christopher L. Wolfgang 《Journal of gastrointestinal surgery》2013,17(2):339-344