全文获取类型
收费全文 | 5234篇 |
免费 | 357篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 131篇 |
儿科学 | 152篇 |
妇产科学 | 116篇 |
基础医学 | 755篇 |
口腔科学 | 172篇 |
临床医学 | 486篇 |
内科学 | 1041篇 |
皮肤病学 | 71篇 |
神经病学 | 298篇 |
特种医学 | 189篇 |
外国民族医学 | 3篇 |
外科学 | 876篇 |
综合类 | 99篇 |
一般理论 | 4篇 |
预防医学 | 295篇 |
眼科学 | 131篇 |
药学 | 420篇 |
中国医学 | 52篇 |
肿瘤学 | 329篇 |
出版年
2024年 | 5篇 |
2023年 | 56篇 |
2022年 | 135篇 |
2021年 | 230篇 |
2020年 | 145篇 |
2019年 | 192篇 |
2018年 | 248篇 |
2017年 | 149篇 |
2016年 | 168篇 |
2015年 | 186篇 |
2014年 | 261篇 |
2013年 | 300篇 |
2012年 | 531篇 |
2011年 | 471篇 |
2010年 | 237篇 |
2009年 | 190篇 |
2008年 | 274篇 |
2007年 | 278篇 |
2006年 | 252篇 |
2005年 | 211篇 |
2004年 | 173篇 |
2003年 | 172篇 |
2002年 | 150篇 |
2001年 | 55篇 |
2000年 | 57篇 |
1999年 | 52篇 |
1998年 | 41篇 |
1997年 | 28篇 |
1996年 | 27篇 |
1995年 | 15篇 |
1994年 | 25篇 |
1993年 | 20篇 |
1992年 | 30篇 |
1991年 | 24篇 |
1990年 | 21篇 |
1989年 | 18篇 |
1988年 | 24篇 |
1987年 | 28篇 |
1986年 | 9篇 |
1985年 | 17篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1974年 | 11篇 |
1973年 | 10篇 |
1971年 | 8篇 |
1967年 | 4篇 |
排序方式: 共有5620条查询结果,搜索用时 0 毫秒
51.
Moyamoya disease is an unusual occlusive cerebrovascular condition commonly seen in children, marked by stenosis of the internal carotid artery and circle of Willis, causing, cerebral ischemia. Moyamoya syndrome is a Moyamoya-like arteriopathy with risk factors including autoimmune disorders, thyroid disease, sickle cell disease, or Down syndrome. Trisomy 21 is a genetic disorder consistent with specific physical and behavioral characteristics, with intellectual impairment. We describe a rare case of Moyamoya syndrome manifesting as ischemic stroke in an adult with Down syndrome 相似文献
52.
Benjamin R.Troutwine Laylan Hamid Colton R.Lysaker Taylor A.Strope Heather M.Wilkins 《药学学报(英文版)》2022,12(2):496-510
Genetic variation in apolipoprotein E (APOE) influences Alzheimer's disease (AD) risk. APOE ε4 alleles are the strongest genetic risk factor for late onset sporadic AD. The AD risk is dose dependent, as those carrying one APOE ε4 allele have a 2–3-fold increased risk, while those carrying two ε4 alleles have a 10–15-fold increased risk. Individuals carrying APOE ε2 alleles have lower AD risk and those carrying APOE ε3 alleles have neutral risk. APOE is a lipoprotein which functions in lipid transport, metabolism, and inflammatory modulation. Isoform specific effects of APOE within the brain include alterations to Aβ, tau, neuroinflammation, and metabolism. Here we review the association of APOE with AD, the APOE isoform specific effects within brain and periphery, and potential therapeutics. 相似文献
53.
Nur Najihah Izzati Mat Rani Xiang Yi Chen Zahraa M.Al-Zubaidi Hanisah Azhari Tzar Mohd Nizam Khaitir Pei Yuen Ng Fhataheya Buang Geok Chin Tan Yin Ping Wong Mazlina Mohd Said Adeel Masood Butt Azmy A.Hamid Mohd Cairul Iqbal Mohd Amin 《Asian Journal of Pharmaceutical Sciences》2022,17(1):102-119
This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and Nhydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine.This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to conf... 相似文献
54.
Snake modeling and distance transform approach to vascular centerline extraction and quantification 总被引:4,自引:0,他引:4
A new method for fully automated centerline extraction and quantification of microvascular structures in confocal microscopy (CM) images is presented. Our method uses the idea of active contour models as well as path planning and distance transforms for the three-dimensional centerline extraction of elongated objects such as vessels. The proposed approach is especially efficient for centerline extraction of complex branching structures. The method performance is validated in several CM images of both normal and stroked rat brains as well as simulated objects. The results confirm the efficiency of the proposed method in extracting the medial curve of vessels, which is essential for the computation of quantitative parameters. 相似文献
55.
56.
57.
Levon N. Nazarian MD 《Journal of ultrasound in medicine》2014,33(9):1521-1532
58.
BackgroundJudging depth is important in surgery. Although there are several cues that permit depth perception, stereoacuity has been singled out as a possible predictor of surgical ability. However, it is not clear whether high-grade stereoacuity is necessary for a career in surgery. To help answer this, we aimed to evaluate stereoacuities in practising surgeons across a range of surgical specialities.MethodsWe recorded stereoacuity values on 66 surgeons working at a London teaching hospital using three standard stereotests: Titmus, TNO and Frisby. There were 36 Trainees and 30 Consultants, covering 12 surgical specialities.ResultsMedian stereoacuities (with range) for the whole group were: 40 s arc on Titmus (40–800), 30 s arc on TNO (15–480) and 20 s arc on Frisby (20–600). Four surgeons had no recordable stereoacuity on TNO, and one was also unrecordable on Titmus. Three of these four were Consultants. Depending on the test used, high-grade stereopsis was found in 74%–83% of surgeons while reduced stereopsis was found in 2%–14% of surgeons.ConclusionWhile we found that most surgeons in current NHS practice have high-grade stereoacuity, there are also surgeons with reduced stereopsis and some with no stereopsis. The findings do not therefore support the assertion that high-grade stereopsis is a universal requirement for a career in surgery. It would be difficult to justify setting a stereoacuity criterion for entrance into a surgical training programme. 相似文献
59.
Parisa Rangraz Hamid Behnam Pooya Sobhebidari Jahan Tavakkoli 《Ultrasound in medicine & biology》2014,40(12):2841-2850
High-intensity focused ultrasound (HIFU) induces thermal lesions by increasing the tissue temperature in a tight focal region. The main ultrasound imaging techniques currently used to monitor HIFU treatment are standard pulse-echo B-mode ultrasound imaging, ultrasound temperature estimation and elastography-based methods. The present study was carried out on ex vivo animal tissue samples, in which backscattered radiofrequency (RF) signals were acquired in real time at time instances before, during and after HIFU treatment. The manifold learning algorithm, a non-linear dimensionality reduction method, was applied to RF signals which construct B-mode images to detect the HIFU-induced changes among the image frames obtained during HIFU treatment. In this approach, the embedded non-linear information in the region of interest of sequential images is represented in a 2-D manifold with the Isomap algorithm, and each image is depicted as a point on the reconstructed manifold. Four distinct regions are chosen in the manifold corresponding to the four phases of HIFU treatment (before HIFU treatment, during HIFU treatment, immediately after HIFU treatment and 10-min after HIFU treatment). It was found that disorganization of the points is achieved by increasing the acoustic power, and if the thermal lesion has been formed, the regions of points related to pre- and post-HIFU significantly differ. Moreover, the manifold embedding was repeated on 2-D moving windows in RF data envelopes related to pre- and post-HIFU exposure data frames. It was concluded that if mean values of the points related to pre- and post-exposure frames in the reconstructed manifold are estimated, and if the Euclidean distance between these two mean values is calculated and the sliding window is moved and this procedure is repeated for the whole image, a new image based on the Euclidean distance can be formed in which the HIFU thermal lesion is detectable. 相似文献
60.
ObjectivesThe aim of the present study is to evaluate the feasibility and safety of performing PNL under local anesthesia in a selected group of patients who are at high risk for general anesthesia.Patients and methodsForty seven patients underwent PNL under local anesthesia. There were 38 males and 9 females with a mean age of 62 years. All patients were at medical high-risk for general anesthesia, with an American Society of Anesthesiologists (ASA) score of 3. The indications for local anesthesia in this study were obstructed single functioning kidney with azotemia in 29 patients, hepatic insufficiency in 8 patients, cardiac problems in 7 patients and 3 patients had hepatocellular carcinoma. The mean stone size was 2.7 cm (range 2–3.1 cm). Local infiltration with 10–20 cc of 2% lidocaine at the site of puncture was used in all cases. Narcotics were given 30 min prior to the procedure and medazolam was given intraoperatively upon demand. Utrasound guided puncture was performed in all cases and tract dilatation was then done under fluoroscopy using high pressure balloon catheter in 35 and Alken's metal dilators in 12 cases. Stones were then retrieved after disintegration in the same cession in 33 patients, while the other 14 patients underwent staged PNL, where a 12 Fr. nephrostomy tube was placed in the first stage, followed by tract dilatation and stone retrieval one week later.ResultsOut of 47 patients included, 44 had successful PNL either one stage (30 patients) or two stages (14 patients). Only 3 patients could not tolerate pain and the procedure was terminated after placement of nephrostomy tube and stone retrieval was completed later under general anesthesia.ConclusionOur results demonstrated that PNL under local anesthesia with narcotics and sedatives seems to be a satisfying solution for the treatment of a selected group of patients with renal pelvic stones and who have high anesthetic risk. However, additional studies with different groups of patients are required to validate our results. 相似文献