全文获取类型
收费全文 | 3205篇 |
免费 | 361篇 |
国内免费 | 223篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 58篇 |
妇产科学 | 59篇 |
基础医学 | 338篇 |
口腔科学 | 44篇 |
临床医学 | 410篇 |
内科学 | 506篇 |
皮肤病学 | 46篇 |
神经病学 | 182篇 |
特种医学 | 107篇 |
外国民族医学 | 2篇 |
外科学 | 294篇 |
综合类 | 388篇 |
预防医学 | 253篇 |
眼科学 | 117篇 |
药学 | 451篇 |
6篇 | |
中国医学 | 179篇 |
肿瘤学 | 324篇 |
出版年
2024年 | 11篇 |
2023年 | 52篇 |
2022年 | 122篇 |
2021年 | 173篇 |
2020年 | 112篇 |
2019年 | 121篇 |
2018年 | 126篇 |
2017年 | 86篇 |
2016年 | 112篇 |
2015年 | 155篇 |
2014年 | 181篇 |
2013年 | 165篇 |
2012年 | 212篇 |
2011年 | 248篇 |
2010年 | 170篇 |
2009年 | 140篇 |
2008年 | 171篇 |
2007年 | 189篇 |
2006年 | 162篇 |
2005年 | 164篇 |
2004年 | 114篇 |
2003年 | 94篇 |
2002年 | 78篇 |
2001年 | 67篇 |
2000年 | 75篇 |
1999年 | 59篇 |
1998年 | 58篇 |
1997年 | 45篇 |
1996年 | 48篇 |
1995年 | 40篇 |
1994年 | 30篇 |
1993年 | 24篇 |
1992年 | 23篇 |
1991年 | 22篇 |
1990年 | 22篇 |
1989年 | 21篇 |
1988年 | 23篇 |
1987年 | 19篇 |
1986年 | 15篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1973年 | 2篇 |
1969年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有3789条查询结果,搜索用时 0 毫秒
41.
目的:研究尖锐湿疣组织中增殖细胞核抗原(PCNA)、P21及环氧化酶-2(COX-2)蛋白表达及其意义。方法:应用免疫组化SP法对30例尖锐湿疣组织及10例正常组织中PCNA、P21及COX-2蛋白进行检测。结果:30例尖锐湿疣组织中PCNA、P21阳性表达较正常对照组有不同程度的增加,有统计学意义;COX-2蛋白在尖锐湿疣组织中阳性表达率13.3%(4/30),正常组织无阳性表达(0/10),两者之间无显著性差异(P〉0.05);尖锐湿疣组织中PCNA与P21表达之间无相关性(r=0.196,P〉0.05)。结论:PCNA、P21过表达与尖锐湿疣角质形成细胞自限性增殖密切相关。 相似文献
42.
Paulo Ricardo Criado Lidi Che Leon Antinori Celina Wakisaka Maruta Vitor Manoel Silva dos Reis 《Anais brasileiros de dermatologia》2013,88(3):355-360
BACKGROUND
It has been demonstrated that neutrophils, eosinophils and monocytes, under appropriated stimulus, may express tissue factor and therefore, activate the extrinsic pathway of coagulation. We performed a transversal and case-control study of patients with chronic urticaria and patients with psoriasis, in our outpatient clinic to evaluate the production of D-dimer.OBJECTIVE
To evaluate D-dimer serum levels in patients with chronic urticaria and its possible correlation with disease activity.PATIENTS AND METHODS
The study was conducted from October 2010 until March 2011. We selected 37 consecutive patients from our Allergy Unit and Psoriasis Unit, and divided them into three groups for statistical analysis: (i) 12 patients with active chronic urticaria (CU); (ii) 10 patients with chronic urticaria under remission and (iii) 15 patients with psoriasis (a disease with skin inflammatory infiltrate constituted by neutrophils, lymphocytes and monocytes). Another five patients with urticarial vasculitis were allocated in our study, but not included in statistical analysis. The serum levels of D-dimer were measured by Enzyme Linked Fluorescent Assay (ELFA), and the result units were given in ng/ml FEU.RESULTS
Patients with active chronic urticaria had the highest serum levels of D-dimer (p<0.01), when compared to patients with CU under remission and the control group (patients with psoriasis).CONCLUSIONS
Patients with active chronic urticaria have higher serum levels of D-dimer, when compared to patients with chronic urticaria under remission and patients with psoriasis. We found elevated serum levels of D-dimer among patients with urticarial vasculitis. 相似文献43.
目的 建立聚(2-乙基-2-NFDE6唑啉)[poly(2-ethyl-2-oxazoline),PEOZ]修饰超氧化物歧化酶(superoxide dismutase,SOD)模拟物脂质体的活性测定方法。方法 以薄膜分散法制备聚(2-乙基-2-NFDE6唑啉)化超氧化物歧化酶模拟物脂质体,利用氮蓝四唑(NBT)光照法对超氧化物歧化酶模拟物及聚(2-乙基-2-NFDE6唑啉)化超氧化物歧化酶模拟物脂质体的活性进行测定。结果 超氧化物歧化酶模拟物的抑制率曲线方程为IR%=33.421lnρ+49.715(r2=0.999 2),IC50为1.008 6×10-3 μmol·L-1;聚(2-乙基-2-NFDE6唑啉)化超氧化物歧化酶模拟物脂质体的抑制率曲线方程IR%=33.521lnρ+49.671(r2=0.999 1),IC50为1.009 9×10-3 μmol·L-1。结论 氮蓝四唑光照法操作简单、稳定可靠、经济实用,可用于超氧化物歧化酶模拟物聚(2-乙基-2-NFDE6唑啉)脂质体的活性测定;经脂质体包裹后超氧化物歧化酶模拟物的活性未发生变化。 相似文献
44.
Ketai LH; Williamson MR; Telepak RJ; Levy H; Koster FT; Nolte KB; Allen SE 《Radiology》1994,191(3):665
45.
目的 探讨甲状腺乳头状癌(PTC)临床病理特征及影响颈部淋巴结转移的危险因素。方法 回顾性分析我院2015年1月~2017年12月收治的515例PTC的临床资料,分析颈部淋巴结转移特点及相关危险因素。结果 PTC颈部淋巴结转移率为44.27%,中央组(Ⅵ区)淋巴结转移率高于侧区(P<0.05)。单因素分析结果示性别、年龄、多灶、癌灶最大径、侵犯被膜和颈部淋巴结转移有关(P<0.05)。多因素分析结果示男性、年龄<55岁、多灶病变、癌灶最大径>10 mm、被膜受侵犯是发生颈部淋巴结转移的独立危险因素(P<0.05)。结论 Ⅵ区转移率最高,行颈淋巴结清扫时应将Ⅵ区作为常规清扫区域。对于男性、年轻、多灶病变、癌灶最大径>10 mm、被膜受侵犯的患者应高度警惕颈部淋巴结转移的可能。 相似文献
46.
47.
目的制备加味双柏软膏,对其质量控制方法进行研究。方法采用薄层色谱图(TLC)鉴别黄柏、侧柏叶,高效液相色谱(HPLC)法测定大黄素、大黄酚含量,并对其质量进行控制。结果黄柏、侧柏叶的薄层鉴别斑点清晰、专属性强;大黄素质量浓度在2.012~50.3μg/m L范围内与峰面积呈良好线性关系(r=0.999 9,n=6),平均回收率为98.82%,RSD为1.62%(n=9);大黄酚质量浓度在5.258~105.16μg/m L范围内与峰面积呈良好线性关系(r=0.999 9,n=6),平均回收率为98.66%,RSD为1.51%(n=9)。结论加味双柏软膏制备工艺合理可行,该法操作简单、专属性强、重复性好、结果准确可靠。 相似文献
48.
Toong Long Jeng Yi Chen Chiang Chia Chi Lai Ting Chen Liao Su Yue Lin Tzu Che Lin Jih Min Sung 《Yao wu shi pin fen xi = Journal of food and drug analysis.》2015,23(3):399
Several studies have reported the therapeutic use of caffeoylquinic acid (CQA) derivatives in the management of hyperglycemia. This study used a simulated in vitro gastrointestinal digestion model to assess the inhibitory effects of CQA derivatives-rich sweet potato leaf extract (SPLE) and a commercially produced green coffee bean extract (GCBE), each with total polyphenols contents of 452 mg g−1 and 278 mg g−1, respectively, against starch digestion. The changes in the amounts of total polyphenols and total CQA derivatives during in vitro gastrointestinal digestion were also examined. The results indicated that both extracts contained substantial levels of CQA derivatives (136 mg g−1 and 83.5 mg g−1 of extract for SPLE and GCBE, respectively). The amounts of total polyphenols and total CQA derivatives in 20 mg of SPLE and GCBE samples decreased from 9.04 mg to 0.58 mg and from 5.56 mg to 0.58 mg, and from 2.72 mg to 0.16 mg and from 1.67 mg to 0.10 mg, respectively, following in vitro gastrointestinal digestion and subsequent dialysis. When SPLE and GCBE were accompanied with starch for in vitro digestion test, they both exhibited inhibitory effect against starch digestion during simulated intestinal digestion, with estimated half maximal inhibitory concentration (IC50) values of 4.91 mg and 6.06 mg polyphenols, respectively. The amount of glucose permeated through dialysis membrane also decreased significantly in comparison with the extract-negative control. Thus, both SPLE and GCBE were capable of modulating the release of glucose from starch digestion in simulated intestinal tract. The observed inhibitory effects against glucose release were presumably due in part to the presence of CQA derivatives in the tested extracts. The SPLE had higher inhibitory effect against in vitro starch digestion than the commercially prepared reference GCBE. Therefore, the SPLE might be used to manage hyperglycemia over the long term. 相似文献
49.
Norlisa Harruddin Syed M. Saufi Che Ku M. Faizal Abdul Wahab Mohammad 《RSC advances》2018,8(45):25396
In this study, the removal of acetic acid by supported liquid membrane (SLM) using hybrid polyethersulfone (PES)–graphene membrane prepared by vapor induced phase separation (VIPS) was investigated. The effects of graphene loading, coagulation bath temperature, air exposure time, and air humidity on the morphology, mechanical strength, porosity, and contact angle of the membrane were analyzed. The performance and stability of the hybrid membrane as a SLM support for acetic acid removal were studied. The best PES–graphene membrane support was produced at a coagulation bath temperature of 50 °C, an air exposure time of 30 s and air humidity of 80%. The fabricated membrane has a symmetrical micropore cellular structure, high porosity and high contact angle. Under specific SLM conditions, almost 95% of acetic acid was successfully removed from 10 g L−1 aqueous acetic acid solution. The hybrid membrane remains stable for more than 116 h without suffering any membrane breakage during the continuous SLM process.In this study, the removal of acetic acid by supported liquid membrane (SLM) using hybrid polyethersulfone (PES)–graphene membrane prepared by vapor induced phase separation (VIPS) was investigated. 相似文献
50.
Liang Hu Xie Peng Linlin Qin Ru Wang Zhengfeng Fang Yan Lin Shengyu Xu Bin Feng De Wu Lianqiang Che 《RSC advances》2018,8(29):16152
The aim of the present study was to investigate the effect of dietary nucleotides supplementation on the antioxidant status of piglets affected by intrauterine growth retardation (IUGR). Fourteen pairs of normal birth weight (NBW) and IUGR piglets were fed either a control diet (CON) or a nucleotides supplementation diet (NT) from 7 d of age to 28 d postnatal. Blood, liver and jejunum samples were collected at the end of the study. The results showed that IUGR piglets had decreased (P < 0.05) concentrations of plasma total antioxidant capability (T-AOC) and total superoxide dismutase (T-SOD), gene expressions of hepatic cytoplasmic copper/zinc SOD (CuZnSOD) and PPARγ coactivator-1α (PGC-1α) and jejunal glutathione peroxidase (GPX) and extracellular superoxide dismutase (ESOD), accordingly, there was markedly higher (P < 0.05) plasma malondialdehyde (MDA) and hepatic and jejunal mitochondria DNA content in the IUGR piglets relative to NBW piglets. Regardless of body weight, dietary NT supplementation significantly increased (P < 0.05) plasma concentrations of T-AOC, T-SOD, CuZnSOD, GPX and the ratio of reduced glutathione to oxidized glutathione, hepatic T-SOD, GPX and mitochondria DNA content, while hepatic MDA concentration was markedly decreased (P < 0.05) 19.1% by NT diet. Furthermore, the gene expressions of hepatic glutathione reductase, CuZnSOD, nuclear erythroid 2-related factor 2, PGC-1α and nuclear respiratory factor-1 (NRF-1) and jejunal GPX, CuZnSOD, ESOD and NRF-1 were significantly increased (P < 0.05) by NT diet, whereas the gene expression of Kelch-like ECH-associated protein 1 were markedly decreased (P < 0.05) compared with that of piglets fed with CON diet. These results indicate that dietary NT supplementation prevents the effect of IUGR on oxidative status and mitochondria DNA damage through improving the non-enzymatic and enzymatic antioxidant capacities as well as mitochondria biogenesis of piglets.The aim of the present study was to investigate the effect of dietary nucleotides supplementation on the antioxidant status of piglets affected by intrauterine growth retardation (IUGR). 相似文献