首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2529篇
  免费   128篇
  国内免费   10篇
耳鼻咽喉   18篇
儿科学   106篇
妇产科学   132篇
基础医学   248篇
口腔科学   70篇
临床医学   213篇
内科学   426篇
皮肤病学   33篇
神经病学   178篇
特种医学   70篇
外科学   431篇
综合类   54篇
一般理论   3篇
预防医学   141篇
眼科学   35篇
药学   213篇
中国医学   13篇
肿瘤学   283篇
  2023年   25篇
  2022年   57篇
  2021年   105篇
  2020年   66篇
  2019年   69篇
  2018年   85篇
  2017年   55篇
  2016年   82篇
  2015年   73篇
  2014年   92篇
  2013年   97篇
  2012年   156篇
  2011年   167篇
  2010年   97篇
  2009年   98篇
  2008年   168篇
  2007年   154篇
  2006年   132篇
  2005年   136篇
  2004年   130篇
  2003年   97篇
  2002年   83篇
  2001年   39篇
  2000年   32篇
  1999年   21篇
  1998年   11篇
  1997年   13篇
  1996年   16篇
  1995年   10篇
  1994年   10篇
  1993年   10篇
  1992年   24篇
  1991年   24篇
  1990年   13篇
  1989年   24篇
  1988年   14篇
  1987年   18篇
  1986年   21篇
  1985年   10篇
  1984年   16篇
  1983年   10篇
  1982年   7篇
  1980年   5篇
  1979年   15篇
  1978年   10篇
  1977年   7篇
  1976年   6篇
  1974年   18篇
  1972年   6篇
  1968年   5篇
排序方式: 共有2667条查询结果,搜索用时 31 毫秒
91.
Metal oxide nanoparticles (NPs) have shown enhanced antibacterial effects against many bacteria. Thus, understanding the potential antibacterial effects of nickel oxide nanoparticles (NiO NPs) against Gram-positive and Gram-negative pathogenic bacteria is an urgent need to enable the exploration of NiO NP use in biomedical sciences. To this end, NiO NPs were synthesized by microwave assisted hydrothermal synthesis method. The synthesized NPs were characterized by X-ray diffraction (XRD) and Fourier Transfer Infrared (FT-IR) and UV-visible spectroscopy. The morphological features of the synthesized NiO NPs were analysed using Transmission Electron Microscopy (TEM) and FE-SEM analysis. The antibacterial activity of NiO NP was explored using different antimicrobial and biophysical studies. The obtained data reveals that the NiO NP has stronger antibacterial activity against Gram-positive bacteria compared to Gram-negative bacteria. The mechanism behind the antibacterial activity of the NiO NP was explored by evaluating the amount of ROS generation at the NiO NP interface. The effect of ROS generation on the bacterial membrane was evaluated by BacLight assay and morphological analysis of the bacterial membrane using FE-SEM. The data altogether suggested that the oxidative stress generated at the NiO NP interface resulted in membrane damage leading to bacterial cell death.

Metal oxide nanoparticles (NPs) have shown enhanced antibacterial effects against many bacteria.  相似文献   
92.
93.

Aim

The ability to identify indicators of poor health-related quality of life (HRQoL) is crucial for both improving clinical care and determining targets of intervention for the prevention and treatment of disease. The main objectives of this study were to assess the HRQoL profile of the hypertensive population from Palestine, and to determine the socio-demographic and clinical characteristics associated with poor HRQoL.

Subject and methods

A cross sectional study was conducted, adopting the EuroQoL-5 Dimensions scale (EQ-5D-5 L) for the assessment of HRQoL. Hypertensive patients attending outpatients’ clinics at Al-Makhfyah primary health care clinic and from Alwatani Hospital, Nablus, Palestine were approached for study.

Results

Four hundred and ten hypertensive patients were enrolled in the study. Of these, 213 patients (52 %) were female. The average age of the study population was 58.38?±?10.65 years. HRQoL was good, with a mean EQ-5D-5 L index value and EQ visual analogue scale (EQ-VAS) score of 0.80?±?0.16 and 74.1?±?15.6 respectively. There was a significant positive correlation (r?=?0.56; p?<?0.001) between the EQ-5D-5 L index values and the reported EQ-VAS scores. A significant difference in EQ-5D-5 L index values was found among participants when grouped according to age, occupation, marital status, income, educational level, duration of disease, total number of chronic diseases, and total number of medications (Kruskal–Wallis test; p-value?<?0.05), as well as gender and therapy type (Mann–Whitney test, p-value?<?0.05).

Conclusions

This study highlighted that specific socio-demographic and disease-related characteristics of hypertensive patients as well as treatment factors were strongly associated with HRQoL. The study findings could be helpful in clinical practice, mainly in the early treatment of hypertensive patients, at a point where improving HRQoL is still possible.  相似文献   
94.

Purpose

Due to diagnosis at advanced stages, comorbidities, and the impact of treatment, patients with hepatocellular carcinoma (HCC) may experience pain. The purpose of this study was to evaluate the psychometric properties of a brief, clinically relevant measure of pain in HCC.

Methods

We conducted a secondary data analysis from four longitudinal studies of patients with HCC (total n = 304). All patients completed the FACT-Hepatobiliary (FACT-Hep) questionnaire, and 49 patients completed the Brief Pain Inventory (BPI) Interference scale. We conducted confirmatory factor analysis (CFA), Rasch modeling, and correlational analysis to assess the psychometrics of the three items on the FACT-Hep that assess HCC-relevant pain scale.

Results

Patients had an average age of 63.5 (±12.2) and were mostly male (76 %). The mean three-item pain subscale score was 8.5 ± 3.0. Seventy-four (24.3 %) patients reported no pain (score = 12). Results of a one-factor CFA supported unidimensionality of the items, and all items fit the Rasch model. An item-person map demonstrated that the three items covered all patients with non-extreme scores. Pain scores were significantly associated with baseline general health-related quality of life (FACT-General, r = 0.60, p < 0.001) and pain interference (BPI, r = ?0.63, p < 0.001).

Conclusions

The three FACT-Hep pain items are unidimensional, cover the range of pain experienced by most patients with HCC, and demonstrate convergent validity. This pain subscale is, if future research demonstrates its sensitivity to change, potentially useful for HCC clinical trials.  相似文献   
95.

Background

Gastric cancer (GC) is a progressive process initiated by Helicobacter pylori-induced inflammation. Initial recognition of H. pylori involves Toll-like receptors (TLRs), central molecules in the host inflammatory response. Here, we investigated the association between novel polymorphisms in genes involved in the TLR signalling pathway, including TLR2, TLR4, LBP, MD-2, CD14 and TIRAP, and risk of H. pylori infection and related GC.

Methods

A case-control study comprising 310 ethnic Chinese individuals (87 non-cardia GC cases and 223 controls with functional dyspepsia) was conducted. Twenty-five polymorphisms were detected by MALDI-TOF mass spectrometry, PCR, PCR–RFLP and real-time PCR.

Results

Seven polymorphisms showed significant associations with GC (TLR4 rs11536889, TLR4 rs10759931, TLR4 rs1927911, TLR4 rs10116253, TLR4 rs10759932, TLR4 rs2149356 and CD14 −260 C/T). In multivariate analyses, TLR4 rs11536889 remained a risk factor for GC (OR: 3.58, 95% CI: 1.20–10.65). TLR4 rs10759932 decreased the risk of H. pylori infection (OR: 0.59, 95% CI: 0.41–0.86). Statistical analyses assessing the joint effect of H. pylori infection and the selected polymorphisms revealed strong associations with GC (TLR2, TLR4, MD-2, LBP and TIRAP polymorphisms).

Conclusions

Novel polymorphisms in TLR2, TLR4, MD-2, LBP, CD14 and TIRAP, genes encoding important molecules of the TLR signalling pathway, showed clear associations with H. pylori-related GC in Chinese.  相似文献   
96.

Introduction

To investigate if decreased exercise capacity is an independent risk factor for major adverse cardiovascular events (MACE) in diabetics and nondiabetics.

Material and methods

The association of decreased exercise capacity (EC) during a treadmill exercise sestamibi stress test with MACE was investigated in 490 nondiabetics and 404 diabetics. Mean follow-up was 53 months.

Results

Nondiabetics with a predicted EC < 85% had a higher prevalence of myocardial ischemia (34% vs. 19%, p = 0.0002), 2- or 3-vessel obstructive coronary artery disease (CAD) (31% vs. 13%, p = 0.016), myocardial infarction (MI) (17% vs. 7%, p = 0.0005), stroke (8% vs. 2%, p = 0.002), death (11% vs. 3%, p = 0.0002), and MI or stroke or death at follow-up (32% vs. 11%, p < 0.001) compared to nondiabetics with a predicted EC ≥ 85%. Diabetics with a predicted EC < 85% had a higher prevalence of myocardial ischemia (48% vs. 32%, p = 0.0009), 2- or 3-vessel obstructive CAD (54% vs. 28%, p = 0.001), MI (32% vs. 14%, p < 0.001), stroke (22% vs. 6%, p < 0.001), death (17% vs. 9%, p = 0.031), and MI or stroke or death at follow-up (65% vs. 27%, p < 0.001). Stepwise Cox regression analysis showed decreased EC was an independent and significant risk factor for MACE among nondiabetics (hazard ratio 3.3, p < 0.0001) and diabetics (hazard ratio 2.7, p < 0.0001).

Conclusions

Diabetics and nondiabetics with decreased EC were at increased risk for MACE with nondiabetics and decreased EC at similar risk as diabetics with normal EC.  相似文献   
97.
In this study, noble ligands of (E)-N′-(benzo[d]dioxol-5-ylmethylene)-4-methyl-benzenesulfonohydrazide (BDMMBSH) were prepared via a simple condensation method using benzo-[d][1,3]-dioxole carbaldehyde, benzenesulfonylhydrazine (BSH), and 4-methyl-benzenesulphonylhydrazine (4-MBSH) in good yield, which were crystallized in acetone, EtOAc, and EtOH. The BDMMBSH derivatives were characterized using different spectroscopic techniques, such as 1H-NMR, 13C-NMR, FTIR, and UV-Vis spectroscopy, and their crystal structures were analyzed using the single crystal X-ray diffraction method (SCXRDM). Subsequently, the BDMMBSH compounds were used for the significant detection of the carcinogenic heavy metal ion, lead (Pb2+), via a reliable electrochemical approach. A sensitive and selective Pb2+ sensor was developed via the deposition of a thin layer of BDMMBSH on a GCE with the conducting polymer matrix Nafion (NF). The sensitivity, LOQ, and LOD of the proposed sensor towards Pb2+ were calculated from the calibration curves to be 2220.0 pA μM−1 cm−2, 320.0 mM, and 96.0 pM, respectively. The validation of the BDMMBSH/GCE/NF sensor probe was performed via the selective determination of Pb2+ in spiked natural samples with a satisfactory and rational outcome.

A sensitive cationic sensor was developed by BDMMBSH onto GCE with 5% Nafion using electrochemical method, which was validated with the selective determination of Pb2+ in spiked samples and found satisfactory results.  相似文献   
98.
99.
BackgroundEfficacy of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil (E/C/F/TDF) in treatment-naïve and experienced patients with HIV infection was demonstrated in phase 3 trials. The primary objective of this study was to evaluate effectiveness and safety of E/C/F/TDF in real world settings.MethodsRetrospective, observational data collected by the Turkish ACTHIV-IST study group between May 2015 and December 2016 were analysed.ResultsA total of 387 patients were prescribed E/C/F/TDF; 210 patients with available data at 6th month were eligible; 91.5% were male, and mean age was 35.2 (SD: 10.8) years; 54.0% of males identified themselves as MSM. Sixty-three percent (133) of the study population were treatment-naïve patients, and 37% (77) were treatment experienced. HIV RNA level was below 100 copies/mL in 78.9% of treatment-naïve patients and 89.9% of treatment experienced patients at month 6. Median increase in CD4 T lymphocyte count was 218 copies/mL in treatment-naïve patients and remained stable or increased in treatment experienced patients. Adverse events were observed in 15% of the patients, and the regimen was discontinued in only six patients.ConclusionReal world data on the effectiveness and safety of E/C/F/TDF is comparable with the phase 3 trial results Adverse events are uncommon and manageable.  相似文献   
100.
Exploring a robust, extremely sensitive, cost-effective and reliable assay platform for the precise analysis of dopamine (DA) has become a big challenge predominantly at the clinical level. To participate in this quest, herein, we fabricated a perylene diimide (PDI) self-assembled graphitic surface of the graphitic pencil electrode (GPE) anchored copper oxide (CuO). The self-assembled N-rich PDI led to the fast movement of ions by decreasing the bandgap and improved the electron transport kinetics with more exposed catalytic active sites, thus resulting in the robust electrochemical sensing of DA. The designed sensor exhibited good sensitivity (4 μM−1 cm−2), high structural stability, repeatability and excellent reproducibility with an RSD value of 2.9%. Moreover, the developed system showed a wide linear range (5 μM to 500 μM) and reliable selectivity even in the presence of co-existing interferants, such as ascorbic acid and uric acid. The fabricated nanohybrid was eventually employed to analyze DA in spiked physiological fluids and provided satisfactory recoveries. The designed PDI-CuO based interface also showed a very low detection limit of 6 nM (S/N = 3), consequently confirming its suitability for clinical and biological applications.

Exploring a robust, extremely sensitive, cost-effective and reliable assay platform for the precise analysis of dopamine (DA) has become a big challenge predominantly at the clinical level.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号