全文获取类型
收费全文 | 1579篇 |
免费 | 100篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 35篇 |
妇产科学 | 19篇 |
基础医学 | 220篇 |
口腔科学 | 72篇 |
临床医学 | 121篇 |
内科学 | 333篇 |
皮肤病学 | 12篇 |
神经病学 | 68篇 |
特种医学 | 59篇 |
外科学 | 350篇 |
综合类 | 29篇 |
一般理论 | 2篇 |
预防医学 | 108篇 |
眼科学 | 51篇 |
药学 | 114篇 |
中国医学 | 5篇 |
肿瘤学 | 99篇 |
出版年
2024年 | 3篇 |
2023年 | 19篇 |
2022年 | 32篇 |
2021年 | 77篇 |
2020年 | 48篇 |
2019年 | 51篇 |
2018年 | 57篇 |
2017年 | 50篇 |
2016年 | 42篇 |
2015年 | 72篇 |
2014年 | 69篇 |
2013年 | 70篇 |
2012年 | 120篇 |
2011年 | 144篇 |
2010年 | 69篇 |
2009年 | 51篇 |
2008年 | 103篇 |
2007年 | 114篇 |
2006年 | 103篇 |
2005年 | 96篇 |
2004年 | 70篇 |
2003年 | 71篇 |
2002年 | 57篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 3篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1992年 | 2篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1969年 | 3篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1964年 | 1篇 |
1909年 | 1篇 |
排序方式: 共有1700条查询结果,搜索用时 15 毫秒
11.
Naqvi SA D'Souza WD Earl MA Ye SJ Shih R Li XA 《Physics in medicine and biology》2005,50(17):4111-4124
For a given linac design, the dosimetric characteristics of a photon beam are determined uniquely by the energy and radial distributions of the electron beam striking the x-ray target. However, in the usual commissioning of a beam from measured data, a large number of variables can be independently tuned, making it difficult to derive a unique and self-consistent beam model. For example, the measured dosimetric penumbra in water may be attributed in various proportions to the lateral secondary electron range, the focal spot size and the transmission through the tips of a non-divergent collimator; the head-scatter component in the tails of the transverse profiles may not be easy to resolve from phantom scatter and head leakage; and the head-scatter tails corresponding to a certain extra-focal source model may not agree self-consistently with in-air output factors measured on the central axis. To reduce the number of adjustable variables in beam modelling, we replace the focal and extra-focal sources with a single phase-space plane scored just above the highest adjustable collimator in a EGS/BEAM simulation of the linac. The phase-space plane is then used as photon source in a stochastic convolution/superposition dose engine. A photon sampled from the uncollimated phase-space plane is first propagated through an arbitrary collimator arrangement and then interacted in the simulation phantom. Energy deposition kernel rays are then randomly issued from the interaction points and dose is deposited along these rays. The electrons in the phase-space file are used to account for electron contamination. 6 MV and 18 MV photon beams from an Elekta SL linac are used as representative examples. Except for small corrections for monitor backscatter and collimator forward scatter for large field sizes (<0.5% with <20 x 20 cm2 field size), we found that the use of a single phase-space photon source provides accurate and self-consistent results for both relative and absolute dose calculations. 相似文献
12.
Shahid M Dhillion VS Jain N Hedau S Diwakar S Sachdeva P Batra S Das BC Husain SA 《Molecular human reproduction》2004,10(7):521-526
13.
Abdul Rafay Qazi Faizan Iqbal Syed Shahid Noor Nasir Ahmed Akram Ali Uddin Nouman Memon Naveed Memon 《Clinics in Orthopedic Surgery》2021,13(1):53
BackgroudDue to extensive fibrosis during revision surgery, adequate exposure is essential and it can be achieved with several extensile approach options, such as tibial tubercle osteotomy. Information regarding surgical exposure during revision arthroplasty is limited in developing countries, such as Pakistan, due to the lack of adequate data collection and follow-up. Therefore, the purpose of this study was to evaluate the impact of tibial tubercle osteotomy on final outcome of revision total knee arthroplasty (TKA).MethodsA total of 231 revision TKAs were performed between January 2008 and December 2017. Twenty-nine patients underwent tibial tubercle osteotomy for adequate exposure during revision surgery. Of these, 27 patients with complete follow-up were included in our study. Factors examined include age at the time of revision surgery, gender, comorbidities, arthroplasty site (right or left), body mass index (BMI), and primary indications for the tibial tubercle osteotomy during revision TKA. Functional outcome was measured by using Knee Society score (KSS) at 3 months and the final follow-up. All statistical analysis was done using SPSS version 20.0 with a p-value < 0.05 considered significant.ResultsOut of 27 patients, 6 patients (22.2%) were men and 21 patients (77.7%) were women. Right knee revision arthroplasty was performed in 15 patients (55.5%), left knee revision arthroplasty was performed in 12 patients (44.4%), and bilateral revision surgery was performed in only 1 patient (3.7%). The mean BMI was 29.2 kg/m2. We used a constrained condylar knee in 20 patients (74%), a rotating hinge knee in 5 patients (18.5%), and mobile bearing tray plus metaphyseal sleeves in 2 patients (7.4%). The KSS was 52.21 ± 4.05 preoperatively, and 79.42 ± 2.2 and 80.12 ± 1.33 at 3 months and 12 months, respectively. Radiological union was achieved in all patients at 3 months. Of 27 patients, only 1 patient (3.7%) had proximal migration of the osteotomy site at 6 months: the patient was asymptomatic and union was also achieved and, therefore, no surgical intervention was performed.ConclusionsTibial tubercle osteotomy during revision TKA can be a safe and reliable technique with superior outcomes and minimal complication rates. 相似文献
14.
Aneurysm formation in the left ventricular outflow tract related to the proximal end of the pulmonary autograft after the Ross procedure was present in 2 patients. Both occurred late after operation and were associated with prolapse of a leaflet of the autograft and significant regurgitation. Both were repaired with no immediate complications. There was no evidence of infection at time of operation. The probable mechanisms underlying this complication and the possibilities of avoiding it are discussed. 相似文献
15.
Shahid M Amjad M Kazmi SU 《Journal of the College of Physicians and Surgeons--Pakistan : JCPSP》1996,6(1):43-46
To investigate the bacterial etiology of infant diarrhea in Karachi, Pakistan, 180 rectal swab samples collected from diarrhea patients under 5 years of age and 30 samples from age- and sex-matched healthy children were analyzed. Enteropathogenic organisms were isolated from 70 case samples (38.9%). The two most common etiologic agents were Campylobacter jejuni (19.4%) and Aeromonas hydrophilia (6.1%). Salmonella, Shigella, and Yersina appear to have a limited incidence in this age group. None of the control specimens yielded any enteropathogen. Breast-fed infants had a significantly lower risk of enteric infection. A pathogen was isolated in 26.0% of samples from breast-fed children with diarrhea compared with 46.8% of samples from bottle-fed diarrhea patients. All C jejuni infections identified in this study involved bottle-fed children. Boiled water was used to prepare infant formula in only 31.1% of these patients. These findings are consistent with those of other studies showing a decreased rate or severity of diarrhea in breast-fed infants. Mothers should be encouraged to breast feed their infants or, if this is not possible, to use boiled water for the preparation of infant formula. 相似文献
16.
Kristen E. Pauken Osmaan Shahid Kaitlyn A. Lagattuta Kelly M. Mahuron Jacob M. Luber Margaret M. Lowe Linglin Huang Conor Delaney Jaclyn M. Long Megan E. Fung Kathleen Newcomer Katy K. Tsai Melissa Chow Samantha Guinn Juhi R. Kuchroo Kelly P. Burke Jason M. Schenkel Michael D. Rosenblum Adil I. Daud Arlene H. Sharpe Meromit Singer 《The Journal of experimental medicine》2021,218(4)
17.
Trivendra Tripathi Mohammad Shahid Adil Raza Haris M. Khan Rahat Ali Khan Abbas Ali Mahdi Mashiatullah Siddiqui Abida Malik Aijaz Ahmed Khan 《Experimental and toxicologic pathology》2012,64(7-8):875-881
ObjectiveThe present study was designed to delineate the hepatotoxicological roles of histamine dose-dependently in immunized rabbits.MethodsThe cohort comprised of three groups (II, III and IV), containing 18 rabbits each, and received subcutaneous histamine 50 μg/kg, 100 μg/kg and 200 μg/kg, respectively for 10 days (b.i.d., starting from 3 days prior to immunization until 7 days after immunization). Group I (control, n = 18) received subcutaneous sterile distilled water for 10 days. They were subsequently immunized at day 3 with intravenous injection of SRBC (1 × 109 cells/ml). Blood samples were collected on pre-immunization (pre-I) day 0, as well as on days 7-, 14-, 21-, 28- and 58-post-immunization (post-I). Biochemical parameters aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin [total bilirubin (TB), direct bilirubin (DB) and indirect bilirubin (IB)] were determined.ResultsGroups II and IV revealed a significant decrease (on day 0-pre-I) and a significant increase (on days 7-, 14-, 21-, 28- and 58-post-I) in ALT and AST levels, when compared with the corresponding values of groups I and III while group II showed a significant increase in ALT and AST levels as compared to group IV. ALP levels in groups II, III and IV showed a significant enhancement when compared with group I. Moreover, results of TB, DB and IB demonstrated increased levels in group III when compared with groups I, II and IV. The results were found statistically significant (p < 0.05).ConclusionShort-term treatment of histamine produces dose-dependent differential patterns of hepatic dysfunctions suggestive mild liver degeneration warranting further long-term studies. 相似文献
18.
19.
20.