全文获取类型
收费全文 | 2352篇 |
免费 | 124篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 104篇 |
妇产科学 | 137篇 |
基础医学 | 360篇 |
口腔科学 | 36篇 |
临床医学 | 133篇 |
内科学 | 537篇 |
皮肤病学 | 43篇 |
神经病学 | 249篇 |
特种医学 | 53篇 |
外科学 | 179篇 |
综合类 | 10篇 |
一般理论 | 1篇 |
预防医学 | 195篇 |
眼科学 | 55篇 |
药学 | 229篇 |
中国医学 | 5篇 |
肿瘤学 | 122篇 |
出版年
2023年 | 18篇 |
2022年 | 96篇 |
2021年 | 136篇 |
2020年 | 64篇 |
2019年 | 81篇 |
2018年 | 86篇 |
2017年 | 56篇 |
2016年 | 75篇 |
2015年 | 75篇 |
2014年 | 89篇 |
2013年 | 116篇 |
2012年 | 180篇 |
2011年 | 162篇 |
2010年 | 95篇 |
2009年 | 71篇 |
2008年 | 145篇 |
2007年 | 131篇 |
2006年 | 113篇 |
2005年 | 100篇 |
2004年 | 122篇 |
2003年 | 97篇 |
2002年 | 90篇 |
2001年 | 25篇 |
2000年 | 33篇 |
1999年 | 19篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 24篇 |
1991年 | 18篇 |
1990年 | 22篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 4篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1981年 | 4篇 |
1978年 | 3篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1972年 | 6篇 |
1970年 | 4篇 |
1969年 | 3篇 |
1968年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有2497条查询结果,搜索用时 15 毫秒
101.
Agata Zamecznik Beata Kierzkowska Katarzyna Niewiadomska-Jarosik Jarosław Rycaj Beata Chodór Jerzy Stańczyk 《Pediatria polska》2014
Cardiomyopathies are a group of rare diseases of a myocardium in a pediatric population which affect 1–1.5 cases per 100 000 children. Restrictive cardiomyopathy (RCM) is the least common type, which constitutes 2–5% of all cardiomyopathies. RCM is characterized by a diastolic dysfunction which is a result of an increased stiffness of the ventricular myocardium with a normal systolic function. Differential diagnosis should include especially constrictive pericarditis. Because of a poor prognosis, it is important to diagnose patients as soon as possible and to early qualify them for a heart transplantation. 相似文献
102.
Loreno M Bucceri AM Catalano F Muratore LA Blasi A Brogna A 《Digestive diseases and sciences》2004,49(3):404-407
We assessed the ultrasonographic pattern of gastric emptying in patients with functional dyspepsia, evaluating its relationship with symptoms. Twenty dyspeptic patients, with slight (group A) and severe (group B) symptoms, and 10 controls (group C) underwent ultrasonographic study of gastric emptying by measuring postprandial variations of the antral area at regular intervals. The time at which the antral area returned to the basal value was assumed to be the final emptying time. The final emptying time was significantly longer in both group A (294 +/- 42 min) and group B (340 +/- 36 min) compared to controls (244 +/- 21 min), but no significant difference was observed between them. A significantly (P < 0.05) greater dilation of the antral area was found at 50 min in group B compared to group A patients. A different pattern of antral motor function rather than a delay of gastric emptying correlates with the severity of symtoms in dyspeptic patients. 相似文献
103.
Spaczyński M Nowak-Markwitz E Basta A Debski R Karowicz-Bilińska A Kedzia W Kotarski J Niemiec T Olejek A Wysocki J;Polish Gynecology Society 《Ginekologia polska》2007,78(3):185-90; supplement 1-6
104.
Wróblewska-Adamek I Wyszyńska M Kabała-Dzik A Mleczko W Picheta A 《Ginekologia polska》2007,78(4):303-306
OBJECTIVES: The aim of the study was to analyze the incidence of malignant cervical carcinomas found in the material from Histopathological Laboratory in Zawiercie District Hospital. MATERIAL AND METHODS: The examined materials included histopathological results concerning segments and scrapings from gynecological procedures and the results of the segments, collected during gynecological operations performed in the years 2000-2005, in which malignant neoplasms of uterine cervix had been diagnosed. The data concerning the neoplasms were analysed, taking into account the following parameters: the number of neoplasms found in relation to the total number of diagnostic procedures performed, patients' age, histological type of the neoplasm and the degree of clinical progression based on FIGO classification. RESULTS: In the examined material, there were 50 cases of cervical carcinomas, with the highest incidence in patients aged between 50-59. The most common morphological type was squamous carcinoma and the majority of cervical carcinomas was characterized by the I degrees of disease clinical progression--38 cases, also 4 preinvasive carcinomas were found and 8 cancers of the II degrees of progression, according to FIGO classification. CONCLUSION: A considerable decrease of cervical carcinomas incidence, observed in the study period and the number of neoplasms found in an early progression stage are the effect of conducted screening examinations, due to which precancerous conditions are diagnosed and treated. 相似文献
105.
Agata Szczesio-Wlodarczyk Aleksander Polikowski Micha Krasowski Magdalena Fronczek Jerzy Sokolowski Kinga Bociong 《Materials》2022,15(7)
Bisphenol A-glycidyl methacrylate (bis-GMA) and urethane dimethacrylate (UDMA) are usually combined with low-viscosity monomers to obtain more desirable viscosity, handling characteristics and general properties. The present study determined the flexural strength (FS), flexural modulus (FM), diametral tensile strength (DTS), and hardness (HV) of five matrices and composites based on these resins. The polymerization shrinkage stress (PSS) was also studied for the composites. The polymer matrices were formed using bis-GMA and UDMA. TEGDMA, HEMA and HDDMA acted as co-monomers. The composites had 45 wt.% of filler content. The highest FS and FM were obtained from the UDMA/bis-GMA/TEGDMA/HEMA matrix and the composite (matrix + filler). The best DTS values were obtained from the UDMA/bis-GMA/HEMA matrix and the composite. One of the lowest values of FS, FM, and DTS was obtained from the UDMA/bis-GMA/HDDMA matrix and the composite. All the composites demonstrated similar hardness values. The lowest polymerization shrinkage stress was observed for the UDMA/bis-GMA/TEGDMA/HEMA composite, and the highest PSS was observed for the UDMA/bis-GMA/TEGDMA/HDDMA composite. The addition of HEMA had a positive effect on the properties of the tested materials, which may be related to the improved mobility of the bis-GMA and UDMA monomers. 相似文献
106.
Reactor-grade niobium steel is used as a construction material for nuclear reactors. In this case, the presence of tantalum, which is characterized by a 20 times higher active cross section for capturing thermal neutrons than the cross section of niobium (181Ta: 21.3 barn), cannot exceed 100 ppm. Analytical methods for quality and new separation method development control need very pure niobium matrices—niobium compounds with a low tantalum content, which are crucial for preparing matrix reference solutions or certified reference materials (CRMs). Therefore, in this paper, a new, efficient method for separating trace amounts of Ta(V) from Nb(V) using extraction chromatography with the use of sorbents impregnated with methyl isobutyl ketone MIBK solvent is proposed. Various types of MIBK-impregnated sorbents were used (AG® 1-X8 Anion Exchange Resin, AMBERLITE™ IRC120 Na Ion Exchange Resin, SERVACEL® Cellulose Anion Exchangers DEAE 52, active carbons of various grain size, carbonized blackcurrant pomace, carbonized chokeberry pomace, bentonite, and polyurethane foam in lumps). The highest tantalum removal efficiency was determined using active coal-based materials (>97%). The separation effectivity of tantalum from niobium was also determined in dynamic studies using a fixed-bed column with MIBK-impregnated active carbon. Solutions of various Nb:Ta weight ratios (1:1, 100:1, 1000:1) were used. The most impressive result was obtaining 70 mL of high purity niobium solution of tantalum content 0.027 ppm (in relation to Nb) with 88.4% yield of niobium from a solution of Nb:Ta, weight ratio 1000:1 (purge factor equaled 35,000). It proves the presented system to be applicable for preparation of pure niobium compounds with very low contents of tantalum. 相似文献
107.
Porcine circovirus type 2 (PCV2) plays a key role in PCV2-associated disease (PCVAD) etiology and has yielded significant losses in the pig husbandry in the last 20 years. However, the impact of two recently described species of porcine circoviruses, PCV3 and PCV4, on the pork industry remains unknown. The presence of PCV3 has been associated with several clinical presentations in pigs. Reproductive failure and multisystemic inflammation have been reported most consistently. The clinical symptoms, anatomopathological changes and interaction with other pathogens during PCV3 infection in pigs indicate that PCV3 might be pathogenic for these animals and can cause economic losses in the swine industry similar to PCV2, which makes PCV3 worth including in the differential list as a cause of clinical disorders in reproductive swine herds. Moreover, subsequent studies indicate interspecies transmission and worldwide spreading of PCV3. To date, research related to PCV3 and PCV4 vaccine design is at early stage, and numerous aspects regarding immune response and virus characteristics remain unknown. 相似文献
108.
Agata Greco Chiara Sorbera Francesco Corallo Matteo Berenati Placido Bramanti Rosanna Palmeri Rosella Ciurleo Silvia MarinoAAS Simona De Salvo Vincenzo Cimino Viviana Lo Buono 《中国神经再生研究》2021,(3):587-590
Anxiety and depression in Parkinson's disease(PD) reduce well-being of the patients.Emotional alterations influence motor skills and cognitive performance;moreover,they contribute significantly and independently to worsen rehabilitative treatment response.We investigated anxiety,depression,and quality of life in PD patients subjected to multidisciplinary rehabilitative training.The self-controlled study included 100 PD patients(49 males and 51 females with the mean age of 64.66 years) admitted to 60 days hospitalization rehabilitative program,between January 2017 and December 2018.Motor,cognitive,linguistic abilities,and functional independence were evaluated at admission(T0 baseline visit) and 60 days after(T1) the multidisciplinary rehabilitation including motor exercises,speech therapies,and cognitive intervention.The multidisciplinary rehabilitation improved functional status in PD patients and exerted its positive effects on mood,motor abilities,autonomy in the activities of daily life,perception of quality of life,cognitive performance and speech skills.Non-motor symptoms may worsen severe disability and reduce quality of life.They are often poorly recognized and inadequately treated.Nonetheless,multidisciplinary rehabilitative training represents an optimal strategy to improve disease management.The study was approved by Istituito di Ricovero e Cura a Carattere Scientifico(IRCCS) Centro Neurolesi "Bonino-Pulejo" Ethical Committee(approval No.6/2016) in June 2016. 相似文献
109.
Emilia Alwin Robert Wojcieszak Kamila Ko
í Miroslava Edelmannov Micha Zieliski Agata Suchora Tomasz Pdziski Mariusz Pietrowski 《Materials》2022,15(3)
Pt, Ru, and Ir were introduced onto the surface of graphitic carbon nitride (g-C3N4) using the wet impregnation method. A reduction of these photocatalysts with hydrogen causes several changes, such as a significant increase in the specific surface area, a C/N atomic ratio, a number of defects in the crystalline structure of g-C3N4, and the contribution of nitrogen bound to the amino and imino groups. According to the X-ray photoelectron spectroscopy results, a transition layer is formed at the g-C3N4/metal nanoparticle interphase, which contains metal at a positive degree of oxidation bonded to nitrogen. These structural changes significantly enhanced the photocatalytic activity in the production of hydrogen through the water-splitting reaction. The activity of the platinum photocatalyst was 24 times greater than that of pristine g-C3N4. Moreover, the enhanced activity was attributed to significantly better separation of photogenerated electron–hole pairs on metal nanoparticles and structural distortions of g-C3N4. 相似文献
110.