全文获取类型
收费全文 | 12766篇 |
免费 | 640篇 |
国内免费 | 112篇 |
专业分类
耳鼻咽喉 | 313篇 |
儿科学 | 652篇 |
妇产科学 | 530篇 |
基础医学 | 923篇 |
口腔科学 | 420篇 |
临床医学 | 1021篇 |
内科学 | 3261篇 |
皮肤病学 | 192篇 |
神经病学 | 752篇 |
特种医学 | 544篇 |
外科学 | 3037篇 |
综合类 | 172篇 |
一般理论 | 1篇 |
预防医学 | 293篇 |
眼科学 | 456篇 |
药学 | 460篇 |
中国医学 | 23篇 |
肿瘤学 | 468篇 |
出版年
2024年 | 11篇 |
2023年 | 111篇 |
2022年 | 208篇 |
2021年 | 392篇 |
2020年 | 247篇 |
2019年 | 305篇 |
2018年 | 385篇 |
2017年 | 307篇 |
2016年 | 524篇 |
2015年 | 600篇 |
2014年 | 654篇 |
2013年 | 788篇 |
2012年 | 1036篇 |
2011年 | 935篇 |
2010年 | 575篇 |
2009年 | 491篇 |
2008年 | 848篇 |
2007年 | 994篇 |
2006年 | 912篇 |
2005年 | 895篇 |
2004年 | 797篇 |
2003年 | 596篇 |
2002年 | 538篇 |
2001年 | 67篇 |
2000年 | 36篇 |
1999年 | 48篇 |
1998年 | 57篇 |
1997年 | 41篇 |
1996年 | 29篇 |
1995年 | 24篇 |
1994年 | 15篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Microvascular reconstruction of a cranial defect in a 10-week-old infant, which is the youngest case in the literature, is reported. A latissimus dorsi free muscle flap was transferred to cover the defect and a split thickness skin graft was placed over the muscle flap. Despite the successful flap transfer in this case, microvascular reconstruction in an infant has its own risks and infants should be discussed as a separate entity apart from the other pediatric patients. 相似文献
32.
Jeffrey A Morgan Ranjit John Yookyung Park Linda J Addonizio Mehmet C Oz Niloo M Edwards Jan M Quaegebeur Ralph S Mosca 《The Journal of heart and lung transplantation》2005,24(1):58-62
BACKGROUND: Many cardiac transplant programs have liberalized donor eligibility criteria in an attempt to maximize donor supply and to accommodate increasing demand. Although many studies have evaluated the potential adverse effects of prolonged donor ischemic time (DIT) in adults undergoing cardiac transplantation, relatively few have focused specifically on pediatric recipients that include a substantial number of patients and long-term follow-up. The focus of this study was to examine the effect of extended DIT on mortality after pediatric heart transplantation. METHODS: We conducted a retrospective review of our pediatric cardiac transplant experience in the past 11 years, comparing patients who received allografts and had ischemic times >240 minutes with those who had ischemic times <240 minutes. RESULTS: A total of 129 pediatric patients (<19 years) underwent orthotopic heart transplantation, of whom 78 (60.5%) had DIT <240 minutes and 51 (39.5%) had DIT >240 minutes. We found no statistically significant difference in age, sex, race, height, weight, or donor age between the groups (p = not significant). Post-transplant survival at 1, 5, and 10 years was similar for both groups: 91.2%, 88.0%, and 85.2%, respectively, for patients with DIT <240 minutes vs 89.6%, 87.2%, and 79.8%, respectively, for patients with DIT >240 minutes (p = 0.433). Additionally, using Cox proportional hazard models, extended DIT >240 minutes was not a statistically significant independent predictor of post-transplant mortality (odds ratio, 0.655; 95% confidence interval, 0.518-0.972; p = 0.684; standard error = 0.468). CONCLUSION: Procurement of hearts from distant locations with associated extended DIT is justified in the setting of increased demand and a fixed donor population. 相似文献
33.
Kemal Gündüz Nazmİ Zengİn Süleyman Okudan Mehmet Okka Nİlgün Özbayrak 《Documenta ophthalmologica. Advances in ophthalmology》1995,91(2):155-164
We recorded pattern electroretinograms and visual evoked potentials in a group of selected patients with unilateral uncomplicated branch retinal vein occlusion. To document the effects of preexisting risk factors, patients were divided into three groups: diabetes mellitus, hypertension with hyperlipidemia and no systemic disease. The transient and steady-state pattern electroretinogram and visual evoked potential amplitudes were significantly reduced and visual evoked potential peak times were delayed relative to the fellow eyes and agematched normal subjects. There was a second amplitude reduction relative to the other patient groups in both the affected and fellow eyes of the diabetes mellitus group, which was indicative of an additive effect of diabetes mellitus.Abbreviations BRVO
branch retinal vein occlusion 相似文献
34.
35.
Onder Güney Jale Bengi Celik Mehmet Arazi Mehmet Erkan Ustun 《Journal of clinical neuroscience》2004,11(5):517-520
This study aims to evaluate the effects of gamma-hydroxybutyrate (GHB) after spinal cord trauma (SCT). Twenty rabbits were divided equally into four groups: group I was the sham-operated group, group II suffered from SCT but received no treatment, group III was given a dose of 400 mg/kg of GHB intravenously before SCT and group IV received the same dose after SCT. Cerebrospinal fluid (CSF) samples were obtained 30 min before SCT (T(0)), at 60 (T(1)) and 120 min (T(2)) after SCT. There was a threefold increase in lactate levels from baseline value at T(2) in group II, while statistically significant elevation of the lactate levels were not observed in groups III and IV. Glucose levels at T(1) and T(2) were significantly lower in groups III and IV compared with the control group. The findings of this study demonstrate that GHB can control the increase of CSF lactate and glucose levels following SCT and that this metabolic effect may be associated with neuroprotective physiological changes. 相似文献
36.
37.
Lipid peroxidation, erythrocyte superoxide-dismutase activity and trace metals in young male footballers 总被引:6,自引:0,他引:6
Metin G Atukeren P Alturfan AA Gulyasar T Kaya M Gumustas MK 《Yonsei medical journal》2003,44(6):979-986
Physical training is known to induce oxidative stress in individuals subjected to intense exercise. In this study, we investigated plasma malondialdehyde (MDA) levels and erythrocyte superoxide dismutase (SOD) activity of 25 young male footballers and a control group of similar age. Red blood cell (RBC) count, haemoglobin (Hb) and haematocrit (Hct) values, and copper (Cu) and zinc (Zn) levels were also examined. The maximal oxygen uptake (VO2max) of all subjects was determined in order to establish their functional capacity. The main finding of the present study was that plasma MDA levels, one of the most commonly used markers of lipid peroxidation, of this group of footballers aged under 21 decreased slightly when compared with those of the control group (p < 0.001). In contrast, erythrocyte SOD activity was higher in the footballer group than in the controls (p < 0.001). Footballers who are under regular training showed an improved antioxidant activity in comparison to sedentary controls. Plasma copper concentration, RBC count and Hb concentration of the footballer group were all significantly lower than those of the control group, (p < 0.001, p < 0.01, p < 0.01, respectively). Investigating the footballers' data with Spearman's correlation analyses, the correlation coefficients (r) between Zn/Cu ratio and SOD was positive (r=0.44; p < 0.05); and between VO2max and SOD (r=0.42; p < 0.05) were both positive. On the basis of statistical analysis, we suggest that regular exercise may be beneficial in cases of oxidative damage by reducing the amount of lipid peroxidation and increasing the activity of the antioxidant enzyme SOD. 相似文献
38.
The aim of this study was to evaluate the effect of self-etching primers on nerve conductance. A self-etching primer (One Up Bond F) which combines etching and bonding in one step, and a fifth-generation bonding agent (Prime&Bond NT ) were tested. Isolated rat sciatic nerves were placed between two platinum electrodes in a bath containing Tyrode solution. The bonding agents were brought into contact with the nerves and the evoked compound action potentials (CAP) were recorded before and after contact with the materials. One Up Bond F caused total inhibition of the CAP within an average time of 7 min. All CAPs in this group were blocked irreversibly. As with Prime&Bond NT, the reduction in CAP was 45.9% after an application time of 15 min, after which readings were terminated. Recovery of the CAP in this group were maintained after rinsing with fresh tyrode solution. One Up Bond F elicited faster blocking of nerve conductance under the conditions of this model. In the context of dentin desensitization with bonding agents, the self-etching primer may be more effective, clinically. 相似文献
39.
The aim of this study was to record sacral bone morphometry that may help in selection of the implant type and proper size in sacroiliac separation. For this reason, sacral lengths and width, the length of each sacral vertebrae, distances between cranial and caudal articular processes, vertical and transversal diameters of the cranial endplate, sacral tuberositas and articular surface areas were obtained from 11 dogs. Additionally, the transverse and vertical diameters of the bony structure and sacral canal were measured from six cross-sections. The data of the study were determined to be representative of the sacral values for average-sized dogs, which was confirmed statistically. The highest value was the sacral width among the linear measurements. The ventral sacral length was longer than the dorsal sacral length. The total lateral area of the sacral wing was measured as 677.46 (142.1)mm2. The transverse diameters of the first sacral vertebra important for screw implantation were 46.02 (4.33)mm and 44.18 (5.29)mm in the first and second cross-sections, respectively. 相似文献
40.
Ozçelik B Serin IS Basbug M Uludag S Narin F Tayyar M 《Human reproduction (Oxford, England)》2003,18(8):1703-1706
BACKGROUND: Our main aim was to investigate the effects of melatonin (ME), possibly the most powerful free-radical scavenger, on the prevention of i.p. adhesion formation in rat uterine horn. Our secondary aim was to determine whether different methods of administration of ME were beneficial. METHODS: Animals were randomly assigned into seven groups, each consisting of 13 rats. Measured serosal injury was created using a standard technique. While control and two sham groups were not given ME, two of the remaining four groups were given a single dose of 10 mg/kg (2 mg) of ME i.p. immediately after injury and 30 min prior to injury respectively. In the two other groups, ME treatment was continued daily for 5 days. All animals were killed 2 weeks after surgery and adhesions were determined and scored by a examiner blinded to the test. RESULTS: The extent, severity and total scores of adhesion were found to be significantly reduced in all of the ME treatment groups when compared with control and sham groups. There were no statistically significant differences between the treatment groups. CONCLUSIONS: This study showed that even single dose ME therapy was effective in the prevention of post- operative i.p. adhesion formation. 相似文献