全文获取类型
收费全文 | 37454篇 |
免费 | 1550篇 |
国内免费 | 763篇 |
专业分类
耳鼻咽喉 | 351篇 |
儿科学 | 706篇 |
妇产科学 | 968篇 |
基础医学 | 4021篇 |
口腔科学 | 689篇 |
临床医学 | 8277篇 |
内科学 | 5056篇 |
皮肤病学 | 284篇 |
神经病学 | 1893篇 |
特种医学 | 2973篇 |
外科学 | 4918篇 |
综合类 | 5189篇 |
现状与发展 | 1篇 |
预防医学 | 954篇 |
眼科学 | 435篇 |
药学 | 1669篇 |
11篇 | |
中国医学 | 423篇 |
肿瘤学 | 949篇 |
出版年
2024年 | 31篇 |
2023年 | 301篇 |
2022年 | 756篇 |
2021年 | 927篇 |
2020年 | 874篇 |
2019年 | 777篇 |
2018年 | 1013篇 |
2017年 | 959篇 |
2016年 | 1759篇 |
2015年 | 1228篇 |
2014年 | 2051篇 |
2013年 | 1994篇 |
2012年 | 1823篇 |
2011年 | 2106篇 |
2010年 | 1819篇 |
2009年 | 1962篇 |
2008年 | 2108篇 |
2007年 | 2086篇 |
2006年 | 2011篇 |
2005年 | 1877篇 |
2004年 | 1626篇 |
2003年 | 1298篇 |
2002年 | 1056篇 |
2001年 | 1061篇 |
2000年 | 849篇 |
1999年 | 696篇 |
1998年 | 583篇 |
1997年 | 554篇 |
1996年 | 509篇 |
1995年 | 495篇 |
1994年 | 393篇 |
1993年 | 315篇 |
1992年 | 286篇 |
1991年 | 258篇 |
1990年 | 193篇 |
1989年 | 122篇 |
1988年 | 129篇 |
1987年 | 113篇 |
1986年 | 97篇 |
1985年 | 124篇 |
1984年 | 91篇 |
1983年 | 66篇 |
1982年 | 66篇 |
1981年 | 44篇 |
1980年 | 35篇 |
1979年 | 35篇 |
1978年 | 35篇 |
1977年 | 30篇 |
1976年 | 35篇 |
1973年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《Ultrasound in medicine & biology》2022,48(8):1361-1372
In recent years, thermal ablation has played an increasingly important role in treating various tumors in the clinic. A practical thermochromic phantom model can provide a favorable platform for clinical thermotherapy training of young physicians or calibration and optimization of thermal devices without risk to animals or human participants. To date, many tissue-mimicking thermal phantoms have been developed and are well liked, especially the polyacrylamide gel (PAG)–based phantoms. This review summarizes the PAG-based phantoms in the field of thermotherapy, details their advantages and disadvantages and provides a direction for further optimization. The relevant physical parameters (such as electrical, acoustic, and thermal properties) of these phantoms are also presented in this review, which can assist operators in a deeper understanding of these phantoms and selection of the proper recipes for phantom fabrication. 相似文献
2.
Sports Imaging has dramatically increased in the past decade with increasing number of adolescents, young and middle-aged adults participating in non-competitive/hobby sports. Therefore, sports injuries are no longer confined to elite athletes. Furthermore, newer forms of sports such as mountain climbing, pickle ball and curling etc. are gaining popularity. Majority of the injuries in sports medicine are from musculoskeletal trauma. Therefore, it is imperative that the musculoskeletal radiologist becomes familiar with various sports related injury patterns as these are commonly encountered in daily practice. This update aims to briefly encapsulate the major aspects of sports imaging. It includes the imaging manifestations of various types of musculoskeletal injuries on different modalities (commonly US and MRI) and briefly mentions the various image guided interventions, performed both on the sports field and in the hospital setting. 相似文献
3.
BackgroundLittle is known about the extent of ordering low-value services by.PurposeTo compare the rates of low-value back images ordered by primary care physicians (PCMDs) and primary care nurse practitioners (PCNPs).MethodWe used 2012 and 2013 Medicare Part B claims for all beneficiaries in 18 hospital referral ?regions (HRRs) and a measure of low-value back imaging from Choosing Wisely. Models included random clinician effect and fixed effects for beneficiary age, disability, Elixhauser comorbidities, clinician sex, the emergency department setting, back pain visit volume, organization, and region (HRR).FindingsPCNPs (N = 231) and PCMDs (N = 4,779) order low-value back images at similar rates (NP: all images: 26.5%; MRI/CT: 8.4%; MD: all images: 24.5%; MRI/CT: 7.7%), with no detectable significant difference when controlling for covariates.DiscussionPCNPs and PCMDs order low-value back images at an effectively similar rate. 相似文献
4.
5.
6.
7.
Aaron Pitzele Mohammad Rahimi Eric Armbrecht 《The journal of maternal-fetal & neonatal medicine》2015,28(15):1770-1773
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion. 相似文献
8.
Improvement in Tricuspid Annular Plane Systolic Excursion with Pulmonary Hypertension Therapy in Pediatric Patients 下载免费PDF全文
9.
《Biomaterials》2015
Controlling cellular alignment is critical in engineering intestines with desired structure and function. Although previous studies have examined the directional alignment of cells on the surface (x–y plane) of parallel fibers, quantitative analysis of the cellular alignment inside implanted scaffolds with oriented fibers has not been reported. This study examined the cellular alignment in the x–z and y–z planes of scaffolds made with two layers of orthogonally oriented fibers. The cellular orientation inside implanted scaffolds was evaluated with immunofluorescence. Quantitative analysis of coherency between cell orientation and fiber direction confirmed that cells aligned along the fibers not only on the surface (x–y plane) but also inside the scaffolds (x–z & y–z planes). Our study demonstrated that two layers of orthogonally aligned scaffolds can generate the histological organization of cells similar to that of intestinal circular and longitudinal smooth muscle. 相似文献
10.
Dynamic LVOT Obstruction and Aortic Stenosis in the Same Patient: A Case of Challenging Doppler Hemodynamics 下载免费PDF全文
Matthew W. Parker M.D. Francis J. Kiernan M.D. 《Echocardiography (Mount Kisco, N.Y.)》2015,32(6):1030-1032
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction. 相似文献