全文获取类型
收费全文 | 47757篇 |
免费 | 4536篇 |
国内免费 | 3633篇 |
专业分类
耳鼻咽喉 | 300篇 |
儿科学 | 430篇 |
妇产科学 | 482篇 |
基础医学 | 5638篇 |
口腔科学 | 800篇 |
临床医学 | 6921篇 |
内科学 | 7464篇 |
皮肤病学 | 587篇 |
神经病学 | 2603篇 |
特种医学 | 1931篇 |
外国民族医学 | 23篇 |
外科学 | 4383篇 |
综合类 | 7710篇 |
现状与发展 | 15篇 |
一般理论 | 7篇 |
预防医学 | 2925篇 |
眼科学 | 1468篇 |
药学 | 5032篇 |
82篇 | |
中国医学 | 2840篇 |
肿瘤学 | 4285篇 |
出版年
2024年 | 153篇 |
2023年 | 857篇 |
2022年 | 2047篇 |
2021年 | 2622篇 |
2020年 | 1982篇 |
2019年 | 1658篇 |
2018年 | 1760篇 |
2017年 | 1519篇 |
2016年 | 1458篇 |
2015年 | 2174篇 |
2014年 | 2641篇 |
2013年 | 2345篇 |
2012年 | 3469篇 |
2011年 | 3887篇 |
2010年 | 2364篇 |
2009年 | 1854篇 |
2008年 | 2481篇 |
2007年 | 2548篇 |
2006年 | 2479篇 |
2005年 | 2569篇 |
2004年 | 1487篇 |
2003年 | 1330篇 |
2002年 | 1120篇 |
2001年 | 1101篇 |
2000年 | 1150篇 |
1999年 | 1212篇 |
1998年 | 791篇 |
1997年 | 804篇 |
1996年 | 617篇 |
1995年 | 568篇 |
1994年 | 515篇 |
1993年 | 303篇 |
1992年 | 378篇 |
1991年 | 310篇 |
1990年 | 282篇 |
1989年 | 243篇 |
1988年 | 230篇 |
1987年 | 208篇 |
1986年 | 154篇 |
1985年 | 111篇 |
1984年 | 50篇 |
1983年 | 38篇 |
1982年 | 19篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1966年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
The effects of acidic treatment, cellulase hydrolysis, particle size distribution and pH on the adsorption capacity of defatted coconut cake dietary fibers (DCCDF) were studied. The results demonstrated that cellulase hydrolysis could significantly improve the soluble dietary fiber content, water holding ability and adsorption ability of DCCDF on cholesterol, bile and nitrite ions. Acidic treatment enhanced the oil holding capacity and adsorption ability in cholesterol and nitrite ions. Moreover, the adsorption ability of DFs in cholesterol, nitrite and bile all increased with reduced particle size (250 to 167 μm), and DCCDF demonstrated a higher adsorption capacity at pH 2.0 than at pH 7.0. The change in adsorption capacity of DCCDF might be suitable for application in the food industry as a low-calorie and cholesterol lowering functional ingredient.This paper provides valuable information on the effects of cellulase hydrolysis, acidic treatment, particle size distribution and pH on the adsorption activity of coconut cake dietary fibers. 相似文献
992.
Xiao-Lan Ying Zhen-Yan Gao Jin Yan Meng Zhang Ju Wang Jian Xu 《Clinical toxicology (Philadelphia, Pa.)》2018,56(6):397-403
Objectives: This study explored the sources of lead exposure, identified patients’ geographic distribution and evaluated the symptoms of children with elevated blood lead levels (BLLs) referred to a pediatric lead specialty clinic in China.Material and methods: Data were collected from 515 consecutive outpatients attending the Pediatric Lead Poisoning Clinic in Xinhua Hospital, Shanghai, China, between 2011 and 2016, referred for BLLs ≥5?μg/dL. Atomic absorption spectrometry was used to measure venous BLLs.Results: The mean?±?standard deviation age of the patients was 4.1?±?3.2 years. Their BLLs ranged from 5 to 126?μg/dL. The geometric mean and median BLLs were 24 and 26?μg/dL, respectively. Two hundred and twenty-two children (43.1%) were exposed to industrial lead pollution—mainly from Zhejiang, Jiangsu, Hunan, Henan and Anhui provinces; whereas, 41.4% (213 cases) were induced by folk medicines used widely throughout China. Other nonindustrial sources of lead exposure included lead-containing tinfoil and tin pots. Household lead paint was a rare source. Most patients exhibited nonspecific symptoms, such as hyperactivity, attention difficulty, aggressiveness, constipation and anorexia.Conclusions: Industrial pollution and folk medicines are important sources of lead exposure in China. Childhood lead poisoning may be difficult to diagnose clinically as symptoms are nonspecific. Thus, blood lead screening may be necessary to identify children at high risk of exposure. Education to raise the awareness of potential sources of exposure resulting in their elimination would be expected to decrease the incidence of children with elevated BLLs. 相似文献
993.
Yuan Tian Ying Yuan Hang Lu Liang Xu Wei Xian Yang Chao Wei Mu Hai Bo Liu Jue Chen Ke Fei Dou Yi Da Tang Jin Qing Yuan Yong Jian Wu Hong Bing Yan Bo Xu Shu Bin Qiao Yue Jin Yang Run Lin Gao Hong Qiu 《The international journal of cardiovascular imaging》2018,34(9):1331-1337
With the development of coronary angiography for the diagnosis of coronary artery disease, its clinical significance in detecting coronary artery anomalies and evaluating the seriousness is attracting more attention. In the study we aimed to assess the prevalence of anomalous origin of coronary arteries in a Chinese population who underwent coronary angiography for coronary artery disease, and explore any patterns in the common variants and typical anomalies, especially the potentially serious ones. Patients who underwent coronary angiography from January 2013 to December 2016 in Fuwai Hospital were included. Baseline characteristics and angiographic data were collected, the incidence of anomalous origin of coronary arteries was calculated, and the typical patterns were analyzed. Comparisons between the present results and those of existing reports were also conducted. A total of 110,158 patients were included in the study, among which 0.76% (835 cases) had anomalous origin of coronary arteries. Among the anomalies, the incidences of anomalous origin of the right coronary artery (RCA), the left coronary artery (LCA), both the RCA and LCA, single coronary artery (SCA) and dextrocardia were 76.76% (641 cases), 14.61% (122 cases), 1.80% (15 cases), 4.67% (39 cases) and 2.16% (18 cases), respectively. Moreover, 47.54% (397 cases) of the anomalies were shown to be potentially serious, and an RCA arising from the left sinus of Valsalva (LSV) was the most common subtype (39.28%, 328 cases). Although anomalous origin of coronary arteries is not quite common, more clinical attention should be paid to this condition due to the potential risk of serious sequelae. 相似文献
994.
Ma X.Dai J.Xu L.Zhang S.Gao L. 《中国感染与化疗杂志》2018,(1):124-128
[No abstract available] 相似文献
995.
Huang R.Gao L.Sun Y.Ren Y.Bian X. 《中国感染与化疗杂志》2018,(1):30-36
Objective To evaluate the efficacy of daptomycin in the treatment of left-sided infective endocarditis after failing to respond to vancomycin. Methods A retrospective analysis was conducted for 6 cases of infective endocarditis. Results Five of the six infective endocarditis patients were complicated with paravalvular abscess (artificial valve in 3 cases, native valve in 2 cases). Their disease deteriorated even under vancomycin treatment. Four of these patients received emergency valve replacement surgery but still febrile after operation. The antimicrobial therapy was switched to daptomycin at dose of 6 mg/kg daily for 2 to 4 weeks. The patients responded satisfactorily to daptomycin. The infection was controlled to some extent in the fifth patient after switching to daptomycin, but recurred later, and died suddenly on day 21 after reoperation. The sixth patient had infective endocarditis of native valve, and had treated with piperacillin-tazobactam for 2 weeks and vancomycin for 3 weeks, but responded poorly. The patient still had fever and enlarged vegetation. Switching to daptomycin reduced the body temperature and vegetation. Serum creatine kinase elevated moderately in one patient, and normal in the other 5 patients. No other apparent adverse reaction was reported. One patient died and the other five patient survived well for 18 months to 5 years. Conclusions Preliminary observation demonstrates the efficacy of daptomycin salvage treatment in a few cases of left-sided infective endocarditis after failing to respond to vancomycin therapy. © 2018, Editorial Department of Chinese Journal of Infection. All rights reserved. 相似文献
996.
Mengci He Fanpeng Kong Geping Yin Zhe Lv Xiudong Sun Hongyan Shi Bo Gao 《RSC advances》2018,8(26):14369
Molybdenum disulfide (MoS2) is a promising electrocatalyst for hydrogen evolution reaction (HER), but only edges and S-vacancies are catalytic active sites for the HER. Therefore, it is crucial to increase edge sites and S-vacancies for enhancing the HER activity of MoS2. Here, we report an enhanced HER activity of MoS2 by combing vertical nanosheets and H2 annealing. Compared to horizontal MoS2 nanosheets, pristine vertical MoS2 nanosheets showed better HER activity due to a larger amount of edges. H2 annealing further enhanced the HER activity of vertical MoS2 nanosheets remarkably. Scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS) and electrochemical impedance spectroscopy (EIS) were used to elucidate the enhanced HER activity by H2 annealing. SEM images showed that H2 annealing roughened the MoS2 edges, leading to more edge sites. XPS data revealed the smaller S : Mo ratio after H2 annealing, meaning more S-vacancies. Meanwhile, EIS measurements showed that charge transfer was accelerated by H2 annealing. These findings elaborated the H2 annealing induced enhancement of the HER activity, which were further confirmed by the subsequent re-sulfurization experiment.Vertical configuration and H2 annealing enhanced the hydrogen evolution reaction activity of MoS2 nanosheets. 相似文献
997.
Four novel coordination polymers (CPs) based on a new 4-(3,5-dicarboxylphenyl) picolinic acid ligands (H3L), [M3(L)2(H2O)6]·4H2O (M3 = Mn3, 1; Co3, 2; Ni3, 3, Co1.01Ni1.99, 4), have been hydrothermally synthesized, and structurally and magnetically characterized. In these isomorphous CPs, octahedrally coordinated metal ions are linked by the single syn–anti carboxylate bridge (μ-COO) to give linear trinuclear motifs. The motifs are connected through the other single syn–anti carboxylate bridge (μ-COO) to give a 2D (4,4) layer, and the layers are interlinked by the L ligands into 3D frameworks. Magnetic measurement indicates that antiferromagnetic interactions between metal ions are mediated through the single syn–anti carboxylate bridges in 1 and 2, while the same carboxylate bridges in 3 transmit ferromagnetic couplings. The bimetallic CP 4 shows interesting complicated magnetic behaviors due to the competition effect of Co(ii) and Ni(ii) ions.Four 3D carboxylate-bridged metal(II) compounds were prepared. Mn(II) and Co(II) compounds show AFM interactions, while FM coupling is found in Ni(II) compound. The bimetallic shows interesting competition effect of FM and AFM interactions. 相似文献
998.
Donglin Zeng Fei Gao Kuolung Hu Catherine Jia Joseph G. Ibrahim 《Statistics in medicine》2015,34(16):2417-2426
Simon's two‐stage designs are widely used in cancer phase II clinical trials for assessing the efficacy of a new treatment. However in practice, the actual sample size for the second stage is often different from the planned sample size, and the original inference procedure is no longer valid. Previous work on this problem has certain limitations in computation. In this paper, we attempt to maximize the unconditional power while controlling for the type I error for the modified second stage sample size. A normal approximation is used for computing the power, and the numerical results show that the approximation is accurate even under small sample sizes. The corresponding confidence intervals for the response rate are constructed by inverting the hypothesis test, and they have reasonable coverage while preserving the type I error. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
Chun-Hong Gao Xing-Juan Ma Yue Zhang Fu-Xing Yu Zi-Yang Xiong Zhi-Qiang Wang Run Wang Ya-Lan Jia Dong-Ying Zhou Zu-Hong Xiong 《RSC advances》2018,8(28):15698
A novel mixed perovskite emitter layer is applied to design all-inorganic cesium lead halide perovskite light-emitting diodes (PeLEDs) with high electroluminescence (EL) performance, by combining CsPbBr3 with iridium(iii)bis[2-(4′,6′-difluorophenyl)pyridinato-N,C2′]-picolinate (FIrpic), where FIrpic is a phosphorescent material with very high internal quantum efficiency (IQE) approaching 100%. The CsPbBr3:FIrpic PeLEDs show a maximum luminance of 5486 cd m−2, and an external quantum efficiency of 0.47%, which are 1.84 and 1.76 times that of neat CsPbBr3 PeLEDs, respectively. It is found that FIrpic molecules as an assistant dopant can efficiently transmit energy from the excitons of FIrpic to the excited state of the CsPbBr3 emitter via a Förster energy transfer process, leading to enhanced EL efficiency in the CsPbBr3:FIrpic PeLEDs.Remarkable EL performance is achieved in CsPbBr3:FIrpic perovskite light-emitting diodes assisted by a phosphorescent material. 相似文献
1000.