全文获取类型
收费全文 | 490165篇 |
免费 | 80862篇 |
国内免费 | 29727篇 |
专业分类
耳鼻咽喉 | 4724篇 |
儿科学 | 8337篇 |
妇产科学 | 5202篇 |
基础医学 | 68945篇 |
口腔科学 | 11762篇 |
临床医学 | 68345篇 |
内科学 | 80163篇 |
皮肤病学 | 11126篇 |
神经病学 | 34002篇 |
特种医学 | 17288篇 |
外国民族医学 | 260篇 |
外科学 | 52906篇 |
综合类 | 73377篇 |
现状与发展 | 94篇 |
一般理论 | 64篇 |
预防医学 | 31369篇 |
眼科学 | 13241篇 |
药学 | 51796篇 |
445篇 | |
中国医学 | 26310篇 |
肿瘤学 | 40998篇 |
出版年
2024年 | 1364篇 |
2023年 | 5936篇 |
2022年 | 16841篇 |
2021年 | 22596篇 |
2020年 | 20765篇 |
2019年 | 23675篇 |
2018年 | 24015篇 |
2017年 | 23968篇 |
2016年 | 23856篇 |
2015年 | 30004篇 |
2014年 | 34459篇 |
2013年 | 32622篇 |
2012年 | 34894篇 |
2011年 | 38340篇 |
2010年 | 30844篇 |
2009年 | 22743篇 |
2008年 | 24243篇 |
2007年 | 23278篇 |
2006年 | 22693篇 |
2005年 | 21802篇 |
2004年 | 14504篇 |
2003年 | 13623篇 |
2002年 | 11759篇 |
2001年 | 10322篇 |
2000年 | 10389篇 |
1999年 | 10337篇 |
1998年 | 6551篇 |
1997年 | 6623篇 |
1996年 | 5081篇 |
1995年 | 4808篇 |
1994年 | 4067篇 |
1993年 | 2776篇 |
1992年 | 3269篇 |
1991年 | 2788篇 |
1990年 | 2418篇 |
1989年 | 2101篇 |
1988年 | 1831篇 |
1987年 | 1556篇 |
1986年 | 1309篇 |
1985年 | 1075篇 |
1984年 | 756篇 |
1983年 | 539篇 |
1982年 | 395篇 |
1981年 | 356篇 |
1980年 | 288篇 |
1979年 | 295篇 |
1978年 | 209篇 |
1977年 | 216篇 |
1976年 | 194篇 |
1974年 | 165篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Guoliang Zhang & Tao Xiong 《Communications In Computational Physics》2022,32(1):126-155
We propose a high order finite difference linear scheme combined with a
high order bound preserving maximum-principle-preserving (MPP) flux limiter to
solve the incompressible flow system. For such problem with highly oscillatory structure but not strong shocks, our approach seems to be less dissipative and much less
costly than a WENO type scheme, and has high resolution due to a Hermite reconstruction. Spurious numerical oscillations can be controlled by the weak MPP flux
limiter. Numerical tests are performed for the Vlasov-Poisson system, the 2D guiding-center model and the incompressible Euler system. The comparison between the linear
and WENO type schemes, with and without the MPP flux limiter, will demonstrate the
good performance of our proposed approach. 相似文献
32.
33.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia. 相似文献
34.
Clinical and Experimental Medicine - Recently, the use of novel targeted drugs significantly improved the overall response rate (ORR) and survival of patients with relapsed/refractory chronic... 相似文献
35.
目的 通过分析特发性肺纤维化急性加重期(AE-IPF)患者证候与血清生物标志物的关系,为中医辨证治疗提供参考。方法 采用观察性研究设计,收集2019年3月至2019年11月三个中心的AE-IPF患者76例,其中痰热壅肺证26例、痰浊阻肺证50例,并纳入健康志愿者10例作为对照。采用ELISA测定患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平,分析与中医证候的相关性。结果 AE-IPF患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平均显著高于健康对照组。血清CCL18、HMGB1、KL-6、MMP-7和SP-D水平在痰热壅肺证和痰浊阻肺证患者间无显著性差异(P>0.05),而血清SP-A水平存在显著性差异(P<0.05)。结论 血清SP-A与AE-IPF证候存在一定的相关性,血清SP-A的浓度升高,与痰热壅肺证关系越密切,反之,血清SP-A浓度降低,则与痰浊阻肺证关系越密切。AE-IPF痰热壅肺证患者的预后可能较痰浊阻肺证患者更差。 相似文献
36.
Byrne Emma Abel Stephen Yu Alexander Shepard Matthew Karlovits Stephen M. Wegner Rodney E. 《Journal of neuro-oncology》2022,157(1):197-205
Journal of Neuro-Oncology - Adjuvant radiation is often used in patients with low grade gliomas with high-risk characteristics with a recommended dose of 45–54 Gy. We used the... 相似文献
37.
宫腔积液指宫腔内液体积存(积水、积血或积脓),是绝经后女性常见体征之一,常于超声检查时发现。持续宫腔积液患者,需宫腔镜检查寻找病因。本文报道1例以宫腔积液为首发症状,经宫腔镜检查确诊为胃型宫颈腺癌的患者。通过病例回顾并文献复习,以期为更多绝经后宫腔积液及宫颈病变的诊断提供参考,避免漏诊及误诊。1病例资料患者67岁,女,主因"绝经18年,不规则阴道出血2月"于2020年5月就诊于首都医科大学附属北京妇产医院妇科微创中心。 相似文献
38.
Sung‐Hyun Hwang Myung‐Chul Kim Sumin Ji Yeseul Yang Yeji Jeong Yongbaek Kim 《Cancer science》2019,110(4):1256-1267
Metformin, a drug for type 2 diabetes mellitus, has shown therapeutic effects for various cancers. However, it had no beneficial effects on the survival rate of human malignant mesothelioma (HMM) patients. The present study was performed to elucidate the underlying mechanism of metformin resistance in HMM cells. Glucose‐starved HMM cells had enhanced resistance to metformin, demonstrated by decreased apoptosis and autophagy and increased cell survival. These cells showed abnormalities in mitochondria, such as decreased ATP synthesis, morphological elongation, altered mitochondrial permeability transition pore and hyperpolarization of mitochondrial membrane potential (MMP). Intriguingly, Mdr1 was significantly upregulated in mitochondria but not in cell membrane. The upregulated mitochondrial Mdr1 was reversed by treatment with carbonyl cyanide m‐chlorophenyl hydrazone, an MMP depolarization inducer. Furthermore, apoptosis and autophagy were increased in multidrug resistance protein 1 knockout HMM cells cultured under glucose starvation with metformin treatment. The data suggest that mitochondrial Mdr1 plays a critical role in the chemoresistance to metformin in HMM cells, which could be a potential target for improving its therapeutic efficacy. 相似文献
39.
Xiumei Jiang Xiaowei Zhang Patrick Gray Jiwen Zheng Timothy R. Croley Peter P. Fu 《journal of environmental science and health part c-environmental carcinogenesis & ecotoxicology reviews》2019,37(2):116-131
Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100?nm) and their implications on intestinal epithelial permeability in vitro. Au NPs aggregated in fasted gastric fluids and generated hydroxyl radicals in the presence of H2O2. Cell studies showed that GIT fluids incubation of Au NPs affected the cellular uptake of Au NPs but did not induce cytotoxicity or disturb the intestinal epithelial permeability. 相似文献