全文获取类型
收费全文 | 68722篇 |
免费 | 5129篇 |
国内免费 | 2008篇 |
专业分类
耳鼻咽喉 | 472篇 |
儿科学 | 966篇 |
妇产科学 | 598篇 |
基础医学 | 7971篇 |
口腔科学 | 1230篇 |
临床医学 | 6560篇 |
内科学 | 6746篇 |
皮肤病学 | 401篇 |
神经病学 | 9158篇 |
特种医学 | 2157篇 |
外国民族医学 | 4篇 |
外科学 | 5212篇 |
综合类 | 11297篇 |
现状与发展 | 7篇 |
一般理论 | 1篇 |
预防医学 | 9843篇 |
眼科学 | 841篇 |
药学 | 7540篇 |
117篇 | |
中国医学 | 2586篇 |
肿瘤学 | 2152篇 |
出版年
2024年 | 85篇 |
2023年 | 965篇 |
2022年 | 1400篇 |
2021年 | 2535篇 |
2020年 | 2578篇 |
2019年 | 1957篇 |
2018年 | 1945篇 |
2017年 | 2019篇 |
2016年 | 2227篇 |
2015年 | 2169篇 |
2014年 | 4375篇 |
2013年 | 4879篇 |
2012年 | 4282篇 |
2011年 | 4713篇 |
2010年 | 3668篇 |
2009年 | 3515篇 |
2008年 | 3622篇 |
2007年 | 3461篇 |
2006年 | 3142篇 |
2005年 | 2710篇 |
2004年 | 2273篇 |
2003年 | 2033篇 |
2002年 | 1620篇 |
2001年 | 1380篇 |
2000年 | 1168篇 |
1999年 | 943篇 |
1998年 | 843篇 |
1997年 | 822篇 |
1996年 | 667篇 |
1995年 | 725篇 |
1994年 | 703篇 |
1993年 | 616篇 |
1992年 | 571篇 |
1991年 | 555篇 |
1990年 | 473篇 |
1989年 | 398篇 |
1988年 | 418篇 |
1987年 | 396篇 |
1986年 | 370篇 |
1985年 | 487篇 |
1984年 | 418篇 |
1983年 | 267篇 |
1982年 | 281篇 |
1981年 | 259篇 |
1980年 | 238篇 |
1979年 | 150篇 |
1978年 | 139篇 |
1977年 | 123篇 |
1976年 | 88篇 |
1974年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
41.
《Journal of vascular and interventional radiology : JVIR》2022,33(3):324-332.e2
PurposeTo show that a deep learning (DL)–based, automated model for Lipiodol (Guerbet Pharmaceuticals, Paris, France) segmentation on cone-beam computed tomography (CT) after conventional transarterial chemoembolization performs closer to the “ground truth segmentation” than a conventional thresholding-based model.Materials and MethodsThis post hoc analysis included 36 patients with a diagnosis of hepatocellular carcinoma or other solid liver tumors who underwent conventional transarterial chemoembolization with an intraprocedural cone-beam CT. Semiautomatic segmentation of Lipiodol was obtained. Subsequently, a convolutional U-net model was used to output a binary mask that predicted Lipiodol deposition. A threshold value of signal intensity on cone-beam CT was used to obtain a Lipiodol mask for comparison. The dice similarity coefficient (DSC), mean squared error (MSE), center of mass (CM), and fractional volume ratios for both masks were obtained by comparing them to the ground truth (radiologist-segmented Lipiodol deposits) to obtain accuracy metrics for the 2 masks. These results were used to compare the model versus the threshold technique.ResultsFor all metrics, the U-net outperformed the threshold technique: DSC (0.65 ± 0.17 vs 0.45 ± 0.22, P < .001) and MSE (125.53 ± 107.36 vs 185.98 ± 93.82, P = .005). The difference between the CM predicted and the actual CM was 15.31 mm ± 14.63 versus 31.34 mm ± 30.24 (P < .001), with lesser distance indicating higher accuracy. The fraction of volume present ([predicted Lipiodol volume]/[ground truth Lipiodol volume]) was 1.22 ± 0.84 versus 2.58 ± 3.52 (P = .048) for the current model’s prediction and threshold technique, respectively.ConclusionsThis study showed that a DL framework could detect Lipiodol in cone-beam CT imaging and was capable of outperforming the conventionally used thresholding technique over several metrics. Further optimization will allow for more accurate, quantitative predictions of Lipiodol depositions intraprocedurally. 相似文献
42.
《Saudi Pharmaceutical Journal》2022,30(6):669-678
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction. 相似文献
43.
44.
目的对医院制剂通鼻消涕颗粒对慢性鼻窦炎鼻黏膜功能是否有调控作用进行临床研究。方法 收集慢性鼻窦炎不伴鼻息肉患者,采用单盲方法随机将患者分为治疗组(通鼻消涕颗粒组)和对照组(克拉霉素片组)。分别给予口服通鼻消涕颗粒和克拉霉素片治疗4周,并对治疗前、治疗2周后、治疗4周后的患者进行糖精试验、鼻部症状VAS评分与鼻内镜Lund Kennedy评分。并采用t检验统计分析。比较服药前、服药后的评分变化。结果 VAS评分提示:治疗组中,治疗2周后、治疗4周后与治疗前相比差异均有统计学意义(P<0.05),对照组在治疗后的各个阶段与治疗前相比均无明显差异(P>0.05)。Lund Kennedy评分提示:治疗组在治疗2周后与治疗前无明显差异,但在治疗4周后有明显改善(P<0.05),对照组则在治疗后各个阶段无明显变化(P>0.05)。糖精试验提示2组在治疗后2周患者糖精清除时间差异无统计学意义(P>0.05),但治疗组在治疗4周后患者糖精清除时间低于对照组(P<0.05)。结论 通鼻消涕颗粒对慢性鼻窦炎的鼻黏膜形态与传输功能有明显改善作用,可以促进鼻黏膜纤毛功能的恢复,并优于克拉霉素片组,且无毒副作用,值得临床上推广应用。 相似文献
45.
淋巴管作为循环系统的重要组成部分之一,具有调节机体体液稳态,协助免疫监视和肠道脂质吸收等重要作用。淋巴管新生是机体生理和病理过程中维持脉管系统结构和功能正常的重要手段,淋巴管新生调控对于防治肿瘤、心血管等诸多疾病有着潜在的临床转化意义;淋巴回流功能则与关节炎症等疾病发病机制关系密切。在循环系统中,相较于中医药调控血管相关疾病的发病机制已取得很大进展,近年来对于淋巴管的研究则明显相对滞后。本文从中医药作用于淋巴管新生及回流功能角度对这一领域的研究进展作一综述,以期为临床上中医药治疗相关疾病提供新的思路与方法。 相似文献
46.
《Cancer radiothérapie》2022,26(4):547-556
PurposeSurface-guided radiotherapy is useful for the pre-positioning and monitoring of radiotherapy. The purpose of this study was to investigate the impact of surface guidance on the repeatability of patient localization and to estimate the specific point at which high positional errors occur.Materials and methodsTen patients without the VOXELAN system (non-VXLN group) and 10 patients with the VOXELAN as the pre-positioning procedure (VXLN group) were included in this analysis. Twelve regions of interest (ROI) were defined in all the patients to verify any misalignment during radiotherapy. Thirteen ROIs were defined on the isocenter.ResultsCompared with the non-VXLN group, the translational positional errors of the VXLN group were the same for all the ROIs. The mean translational positional errors of the VXLN group in the longitudinal direction were approximately 0.1 mm, and the standard deviation was the largest among the three directions in all the ROIs. The magnitude of the standard deviation in the non-VXLN group varied independently of the ROI and direction. The standard deviations of the VXLN group in the longitudinal direction were large in all the ROIs, while the standard deviations in the vertical and lateral directions were small.ConclusionPre-positioning with a surface guidance system reduced the body twist and rotation, which could not be corrected by image-guided radiotherapy alone. Since the VOXELAN can detect positioning errors quickly and without additional radiation exposure to the patient, it can be used as a tool for pre-positioning in radiotherapy. 相似文献
47.
48.
《Radiologic clinics of North America》2019,57(6):1117-1131
49.
《Brain & development》2019,41(8):671-677
ObjectiveWe sought to develop and validate a novel scoring system for the prediction of severe intraventricular hemorrhage (SIVH) in very low birth weight infants (VLBWI).MethodsThis retrospective cohort multicenter study included 615 VLBWI born between 24 and 32 weeks gestational age (GA). Multivariable logistic regression analyses were used to determine which factors evaluated within the first 5 days of life were associated with SIVH and the weights of these variables. The accuracy of the predictive scoring system was prospectively tested in the same units.ResultsThe final SIVH scoring system included the following variables: antenatal steroid therapy, GA, birth weight (BW), 1-min Apgar score, mechanical ventilation and hypotension. The SIVH scores used to divide the subjects into three tiers (low-risk (<5), moderate-risk (5–8) and high-risk (>8)) were developed based on these variables. Of infants with a score below 5, 1.2% (4/339) developed SIVH. Of those with a score above 8, 42.5% (17/40) developed SIVH. The scores were successfully verified in 99 VLBWI.ConclusionsThese findings suggest that among infants with a score >8, the incidence of SIVH is significantly higher. This scoring system can be used to predict the incidence of SIVH during the first 5 days after birth and may contribute to the early intervention in and prevention of SIVH. 相似文献
50.