全文获取类型
收费全文 | 23061篇 |
免费 | 2302篇 |
国内免费 | 1924篇 |
专业分类
耳鼻咽喉 | 165篇 |
儿科学 | 274篇 |
妇产科学 | 296篇 |
基础医学 | 2891篇 |
口腔科学 | 283篇 |
临床医学 | 3182篇 |
内科学 | 3471篇 |
皮肤病学 | 221篇 |
神经病学 | 1296篇 |
特种医学 | 1045篇 |
外国民族医学 | 13篇 |
外科学 | 2143篇 |
综合类 | 3800篇 |
现状与发展 | 5篇 |
一般理论 | 1篇 |
预防医学 | 1563篇 |
眼科学 | 665篇 |
药学 | 2590篇 |
31篇 | |
中国医学 | 1524篇 |
肿瘤学 | 1828篇 |
出版年
2024年 | 76篇 |
2023年 | 410篇 |
2022年 | 988篇 |
2021年 | 1235篇 |
2020年 | 988篇 |
2019年 | 751篇 |
2018年 | 784篇 |
2017年 | 803篇 |
2016年 | 753篇 |
2015年 | 1105篇 |
2014年 | 1403篇 |
2013年 | 1204篇 |
2012年 | 1609篇 |
2011年 | 1926篇 |
2010年 | 1231篇 |
2009年 | 1056篇 |
2008年 | 1190篇 |
2007年 | 1203篇 |
2006年 | 1163篇 |
2005年 | 1172篇 |
2004年 | 746篇 |
2003年 | 710篇 |
2002年 | 569篇 |
2001年 | 512篇 |
2000年 | 521篇 |
1999年 | 541篇 |
1998年 | 388篇 |
1997年 | 387篇 |
1996年 | 306篇 |
1995年 | 293篇 |
1994年 | 249篇 |
1993年 | 162篇 |
1992年 | 142篇 |
1991年 | 96篇 |
1990年 | 111篇 |
1989年 | 100篇 |
1988年 | 94篇 |
1987年 | 81篇 |
1986年 | 72篇 |
1985年 | 42篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 12篇 |
1975年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
101.
BackgroundAnti-glomerular basement membrane (anti-GBM) disease is a rare but severe autoantibody-mediated immune disorder. The typical clinical presentation includes rapidly progressive glomerulonephritis and often concurrent pulmonary hemorrhage. The present study is aimed to investigate the therapeutic effects of rituximab either used alone or with other immunosuppressants.MethodsEight patients diagnosed with anti-GBM disease and treated with rituximab from 2014 to 2020 were retrospectively reviewed.ResultsEight patients included 5 males and 3 females with a median age of 58.5 years. They all presented severe kidney injuries and 1 patient had lung hemorrhage. At diagnosis, the median of serum creatinine was 246 µmol/L (ranging from 91 to 850 µmol/L), with 3 patients requiring dialysis. All of them received corticosteroids and plasmapheresis. Rituximab was given as either standard four weekly doses or one pulse ranging from 100 to 600 mg. After a median follow-up of 34.5 months, kidney function was partially recovered or stabilized in 5/8 (62.5%) patients, free of dialysis. Anti-GBM antibodies remained undetected in all patients during follow-up. No severe adverse effect associated with rituximab was observed.ConclusionRituximab may be an alternative therapy in the treatment of patient with severe or refractory anti-GBM disease. 相似文献
102.
Mengdi Zhang Jianhua Liu Chen Li Jianwei Gao Chuanhui Xu Xiaoyu Wu Tiesheng Xu Chenbin Cui Hongkui Wei Jian Peng Rong Zheng 《Nutrients》2022,14(13)
Obesity may cause metabolic syndrome and has become a global public health problem, and dietary fibers (DF) could alleviate obesity and metabolic syndrome by regulating intestinal microbiota. We developed a functional fiber (FF) with a synthetic mixture of polysaccharides, high viscosity, water-binding capacity, swelling capacity, and fermentability. This study aimed to investigate the effect of FF on obesity and to determine its prevention of obesity by modulating the gut microbiota. Physiological, histological, and biochemical parameters, and gut microbiota composition were investigated in the following six groups: control group (Con), high-fat diet group (HFD), low-fat diet group (LFD, conversion of HFD to LFD), high-fat +8% FF group (8% FF), high-fat +12% FF group (12% FF), and high-fat +12% FF + antibiotic group (12% FF + AB). The results demonstrated that 12% FF could promote a reduction in body weight and epididymal adipocyte area, augment insulin sensitivity, and stimulate heat production from brown adipose tissue (BAT) (p < 0.05). Compared with the HFD, 12% FF could also significantly improve the intestinal morphological integrity, attenuate systemic inflammation, promote intestinal microbiota homeostasis, and stabilize the production of short-chain fatty acids (SCFAs) (p < 0.05). Consistent with the results of 12% FF, the LFD could significantly reduce the body weight and epididymal adipocyte area relative to the HFD (p < 0.05), but the LFD and HFD showed no significant difference (p > 0.05) in the level of inflammation and SCFAs. Meanwhile, 12% FF supplementation showed an increase (p < 0.05) in the abundance of the Bifidobacterium, Lactococcus, and Coprococcus genus in the intestine, which had a negative correlation with obesity and insulin resistance. Additionally, the treatment with antibiotics (12% FF + AB) could inhibit the effect of FF in the HFD. The Kyoto Encyclopedia of Genes and Genomes (KEGG) function prediction revealed that 12% FF could significantly inhibit the cyanogenic amino acid metabolic pathway and decrease the serum succinate concentration relative to the HFD group. The overall results indicate that 12% FF has the potential to reduce obesity through the beneficial regulation of the gut microbiota and metabolites. 相似文献
103.
The durability of reinforced concrete (RC) beams strengthened with carbon fiber-reinforced polymer (CFRP) is a worldwide concern in structural engineering. As an important part of the strengthened beam, the performance of the CFRP–concrete interface under hygrothermal environments is a delicate problem. In this paper, the fatigue behavior of CFRP-strengthened RC beams is analyzed by a theoretical model. In the model, CFRP–concrete interface degradation under hygrothermal environments is involved. Since interface debonding and rebar fracture induced by intermediate cracking are two typical failure modes, the damage models of rebar and the CFRP–concrete interface are established. Based on the theoretical model, the failure mode of CFRP-strengthened RC beams can be predicted, and fatigue life can be determined. The results showed that IC debonding is more likely to occur under hygrothermal environments. The accurate prediction of failure modes is essential for fatigue life prediction. 相似文献
104.
Yaqing Zhou Limei Jia Baojin Lu Long Bai Wei Cui 《Journal of clinical hypertension (Greenwich, Conn.)》2022,24(7):898
A simple renal cyst (SRC) may increase the risk for hypertension. The authors examined the relationship between a SRC and hypertension in participants receiving physical examinations at Hebei Medical University. This study enrolled 66 883 participants who received physical examinations at our center from January 2012 to December 2017. Demographic data, medical history related to hypertension, hematological indexes, hypertension, and SRC subtype based on ultrasound examinations were examined. The relationship between SRC and hypertension was analyzed using univariate and multivariate logistic regression analysis in different models. Subgroup analysis and propensity score (PS) matching were also performed. Based on SRC subtype (unitary vs. multiple, small vs. large, unilateral vs. bilateral), a comprehensive scoring system was established to determine the effect of SRC load on hypertension. The results of univariate and multivariate analysis indicated that SRC was a risk factor for hypertension (P < .01). Subgroup and interaction analysis showed the homogeneity that SRC was an independent risk factor for hypertension in multiple subgroups (P > .05). A SRC remained an independent risk factor for hypertension after PS matching (P < .01). Based on a scoring system that considered different SRC subtypes, the risk for hypertension increased with renal cyst load (P < .01). In conclusions, a SRC was an independent risk factor for hypertension, and there was a positive correlation between SRC load and hypertension. The risk of hypertension increased gradually with the size, number, and location of a SRC. Careful follow‐up or excision should be considered for patients with SRCs. 相似文献
105.
106.
Run Huang Yufei Hao Yusong Pan Chengling Pan Xiaolong Tang Lei Huang Chao Du Rui Yue Diansheng Cui 《RSC advances》2022,12(31):20037
Surface treatment is known as a very efficient measure by which to modulate the surface properties of biomaterials in terms of grain structure, topography, roughness and chemistry to determine the osseointegration of implants. In this work, a two-step method of surface modification was employed to impart high osteogenic activity and biomineralization capacity on a Ti–25Nb–3Mo–2Sn–3Zr alloy (a type of β-titanium named TLM). The preliminary surface mechanical attrition treatment (SMAT) refined the average grain size from 170 ± 19 μm to 74 ± 8 nm in the TLM surface layer and promoted the surface to be much rougher and more hydrophilic. The subsequent Ca-ion implantation did not change the surface roughness and topography obviously, but enhanced the surface wettability of the SMAT-treated TLM alloy. The in vitro evaluations of the adhesion, proliferation, osteogenic genes (RUNX2, ALP, BMP-2, OPN, OCN and COL-I) and protein (ALP, OPN, OCN and COL-I) expressions, as well as extracellular matrix (ECM) mineralization of mesenchymal stem cells (MSCs) revealed that the initial SMAT-treated sample significantly enhanced the adhesion and osteogenic functions of MSCs compared to an untreated TLM sample, and the subsequent introduction of Ca ions onto the SMAT-derived nanograined sample further promotes the MSC adhesion, proliferation, osteo-differentiation and ECM mineralization due to the adsorption of more proteins such as laminin (Ln), fibronectin (Fn) and vitronectin (Vn) on the surface, as well as the increase in extracellular Ca concentrations. In addition, the biomineralization capacity of the samples was also evaluated by soaking them in simulated bodily fluid (SBF) at 37 °C for 28 days, and the results showed that the Ca-ion implanted sample significantly boosted the deposition of Ca and P containing minerals on its surface, which was associated with the generation of more Ti–OH groups on the surface after ion implantation. The combination of the SMAT technique and Ca-ion implantation thus endowed the TLM alloy with outstanding osteogenic and biomineralization properties, providing a potential means for its future use in the orthopedic field.Combination of the SMAT technique and Ca-ion implantation produced a β-titanium alloy with a bioactive surface layer, which was proved to effectively promote the osteogenic activity of MSCs and Ca–P mineral deposition in vitro. 相似文献
107.
The primary plasma cell leukemia (pPCL) is a rare but aggressive variant of multiple myeloma (MM). Few studies have focused on the differences in the causes of death between pPCL and MM. This study aimed to compare and evaluate the causes of death of patients with pPCL and MM.The data were collected from the Surveillance Epidemiology, and End Results (SEER) database. The demographic characteristics, survival, and causes of death in pPCL and MM patients were evaluated and compared. The competing risk regression model was performed to predict the cause of death.Between 1975 and 2009, the overall mortality rate was 96.13% and 88.71% for pPCL and MM, and the median survival was 9 and 26 months, respectively. In pPCL, leukemia caused 45.05% of the deaths, followed by myeloma (38.83%). In MM, myeloma was the leading cause of death, accounting for 74.89% of the deaths. Older age at diagnosis was a risk factor for dying of leukemia in pPCL patients (HR = 1.49, 95% CI: 1.16–1.91), while older age at death was associated with reduced risk (HR = 0.67, 95% CI: 0.52–0.86). Although the survival of pPCL patients increased with time periods of diagnosis since 1975 to 2009, the risk of dying of leukemia increased with the periods. For MM, most of the demographic characteristics were found to have independently predicting influence on the cause of death.Patients with pPCL and MM had distinct causes of death. Leukemia was the leading and the most serious cause of death in pPCL patients. The demographic factors could not predict the causes of death in pPCL. More large-scale and multi-center studies are needed to evaluate the effect of novel agents in pPCL patients, especially for patients who have progressed to leukemia. 相似文献
108.
109.
In this paper, the duplex stainless steel welded joints were produced by a K-TIG welding system. The weld geometry parameters under different welding speeds were analyzed by combining the morphological characteristics of the keyhole. The microstructure and impact toughness of the base metal and weld metal zone under different welding speeds were studied. The experiment results show that the welding speed has quite an effect on the geometry profile of the weld. In addition, the characteristic parameters of the keyhole can effectively predict the geometry profile of the weld. The test results prove that the microstructure, Σ3 coincidence site lattice grain boundary, and phase boundary of ferrite and austenite have an effect on the impact property of the weld metal zone. When the proportion of the austenite, Σ3 coincidence site lattice grain boundary and random phase boundary increased, the impact property of the weld metal zone also increased. S32101相似文献
110.
目的探讨噪声暴露对耳蜗外淋巴Ca2 含量的影响,并观察天麻素对噪声性聋的防护作用。方法将42只健康豚鼠随机分为3组,8只为对照组,未作噪声暴露,17只为噪声暴露组,17只为噪声 天麻素组,用天麻素预防,用微量进样-火焰原子吸收光谱法测定耳蜗外淋巴Ca2 含量,检测噪声暴露前、后听性脑干反应(ABR),并与对照组比较。结果噪声暴露组耳蜗外淋巴平均Ca2 含量(113.67±42.22μg/ml)显著低于对照组(196.91±47.10μg/ml)(P<0.01),噪声 天麻素组耳蜗外淋巴平均Ca2 含量(151.15±60.65μg/ml)与对照组差异无统计学意义(P>0.05);噪声暴露后,噪声 天麻素组、噪声暴露组ABR阈值均显著升高(P<0.01),但噪声暴露组(88.53±5.08dBSPL)高于噪声 天麻素组(83.68±4.93dBSPL),差异有统计学意义(P<0.05)。结论噪声暴露可降低耳蜗外淋巴Ca2 含量,后者是噪声致聋的重要发病机理之一;天麻素能减轻噪声暴露引起的外淋巴Ca2 下降,对噪声性聋可能具有一定的预防作用。 相似文献