全文获取类型
收费全文 | 5863篇 |
免费 | 331篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 135篇 |
儿科学 | 189篇 |
妇产科学 | 174篇 |
基础医学 | 992篇 |
口腔科学 | 61篇 |
临床医学 | 456篇 |
内科学 | 1308篇 |
皮肤病学 | 163篇 |
神经病学 | 574篇 |
特种医学 | 76篇 |
外科学 | 453篇 |
综合类 | 31篇 |
一般理论 | 1篇 |
预防医学 | 507篇 |
眼科学 | 99篇 |
药学 | 628篇 |
中国医学 | 13篇 |
肿瘤学 | 367篇 |
出版年
2023年 | 57篇 |
2022年 | 276篇 |
2021年 | 386篇 |
2020年 | 147篇 |
2019年 | 200篇 |
2018年 | 200篇 |
2017年 | 186篇 |
2016年 | 201篇 |
2015年 | 221篇 |
2014年 | 253篇 |
2013年 | 350篇 |
2012年 | 526篇 |
2011年 | 547篇 |
2010年 | 272篇 |
2009年 | 212篇 |
2008年 | 324篇 |
2007年 | 336篇 |
2006年 | 349篇 |
2005年 | 281篇 |
2004年 | 245篇 |
2003年 | 219篇 |
2002年 | 205篇 |
2001年 | 21篇 |
2000年 | 9篇 |
1999年 | 17篇 |
1998年 | 23篇 |
1997年 | 17篇 |
1996年 | 22篇 |
1995年 | 12篇 |
1994年 | 17篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 3篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1972年 | 5篇 |
1971年 | 9篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1967年 | 4篇 |
1965年 | 3篇 |
1964年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有6227条查询结果,搜索用时 10 毫秒
191.
Michał Bogusiewicz Marta Monist Krzysztof Gałczyński Magdalena Woźniak Andrzej P. Wieczorek Tomasz Rechberger 《World journal of urology》2014,32(6):1605-1611
Purpose
To investigate whether the position of the tape under the urethra may influence ‘outside-in’ transobturator sling (TOT) outcome.Methods
The study comprised 141 women who underwent TOT for clinically and urodynamically proved stress urinary incontinence. The postoperative ultrasound examination with an endovaginal biplane probe was performed before discharging the patients from hospital. The measurements obtained described the position of the tape relative to the urethra and pubic symphysis, as well as anatomical relationships in the anterior compartment.Results
Ninety-six (68.1 %) patients were cured, 27 (19.1 %) significantly improved, and in 18 cases (12.7 %), the surgery failed. The tape position under the midurethra (40–70th percentile of the urethral length) or distal urethra (>70th percentile) coincided with better results (cure rate 67.1 and 82.4 %, respectively) than the location in the proximity of the bladder neck (<40th percentile) (21.4 % cured, p = 0.0015 and p < 0.001, respectively). However, the risk of failure was the lowest when the tape was located under the distal urethra. Other ultrasonographic findings were not related to treatment results.Conclusions
The highest failure rate for ‘outside-in’ TOT is associated with the location of the tape under the proximal third of the urethra. Both the middle and distal sections of the urethra may be regarded as targets for transobturator tape placement. 相似文献192.
193.
194.
Agnieszka Sobczak-Kupiec Anna Drabczyk Wioletta Florkiewicz Magdalena Gb Sonia Kudacik-Kramarczyk Dagmara Sota Agnieszka Tomala Boena Tyliszczak 《Materials》2021,14(9)
Regenerative medicine is becoming a rapidly evolving technique in today’s biomedical progress scenario. Scientists around the world suggest the use of naturally synthesized biomaterials to repair and heal damaged cells. Hydroxyapatite (HAp) has the potential to replace drugs in biomedical engineering and regenerative drugs. HAp is easily biodegradable, biocompatible, and correlated with macromolecules, which facilitates their incorporation into inorganic materials. This review article provides extensive knowledge on HAp and collagen-containing compositions modified with drugs, bioactive components, metals, and selected nanoparticles. Such compositions consisting of HAp and collagen modified with various additives are used in a variety of biomedical applications such as bone tissue engineering, vascular transplantation, cartilage, and other implantable biomedical devices. 相似文献
195.
This paper uses mathematical methods as the basic tool at the stage of experiment planning. The importance of research programming applications was shown using the theory of experiments and the STATISTICA software. The method of experiment planning used in the case of studying the properties of a mixture, depending on its composition, features considerable complexity. The aim of the statistical analysis was to determine the influence of variable chemical composition of waste materials on selected properties of glass-ceramic materials. A statistical approach to multicomponent systems, such as ceramic sets, enables the selection of appropriate amounts of raw materials through the application of ‘a plan for mixtures’. To utilize the raw waste materials, e.g., slags from a solid waste incinerator, fly or bottom ashes, in the modeling of new materials, a mathematical relationship was developed, which enables estimating, based on the waste chemical composition, selected technological and practical properties of the glass so as to obtain a material featuring the required technological–practical parameters. For the obtained glasses, a comparative analysis of the experimentally and computationally determined properties was carried out: transformation temperature, liquidus temperature, density, and thermal expansion coefficient. The obtained high theoretical approximation (at the level of determination correlation coefficient R2 > 0.8) confirms the suitability of the polynomial model for mixtures for applications in the design of new glass-ceramic products. 相似文献
196.
Rafa Panek Magdalena Medykowska Katarzyna Szewczuk-Karpisz Magorzata Winiewska 《Materials》2021,14(11)
Considering the growing needs of environmental remediation, new effective solutions should be sought. Therefore, the adsorbed amounts of heavy metal ions, such as lead(II) and zinc(II), on the surface of high-carbon fly ash (HiC FA), zeolite-–carbon composite (Na-P1(C)) and pure zeolite (Na-P1), were investigated. The applied solids were characterized using the following techniques: XRD, SEM-EDS, TEM, porosimetry, SLS, electrophoresis and potentiometric titration. The heavy metal concentration in the probes was determined by applying ICP-OES spectroscopy. Adsorption/desorption and electrokinetic measurements were performed in the systems containing one or two adsorbates. The obtained results indicated that Pb(II) ions are adsorbed in larger amounts on the investigated solid surface due to the molecular sieving effect. The largest adsorption capacity relative to lead(II) ions was observed for pure Na-P1 zeolite (407 mg/g). The simultaneous presence of Pb(II) + Zn(II) mixed adsorbates minimally affects the amount of adsorbed Pb(II) ions and causes a significant decrease of Zn(II) ion adsorption (in comparison with analogous systems containing single adsorbates). It was also shown that all solids can be efficiently regenerated using hydrochloric acid. Thus, the selected pure zeolite can be successfully applied in soil remediation or other purifying technologies as an effective Pb(II) adsorbent. 相似文献
197.
Externally bonded reinforcements are commonly and widely used in civil engineering objects made of concrete to increase the structure load capacity or to minimize the negative effects of long-term operation and possible defects. The quality of adhesive bonding between a strengthened structure and steel or composite elements is essential for effective reinforcement; therefore, there is a need for non-destructive diagnostics of adhesive joints. The aim of this paper is the detection of debonding defects in adhesive joints between concrete beams and steel plates using the modal analysis approach. The inspection was based on modal shapes and their further processing with the use of continuous wavelet transform (CWT) for precise debonding localization and imaging. The influence of the number of wavelet vanishing moments and the mode shape interpolation on damage imaging maps was studied. The results showed that the integrated modal analysis and wavelet transform could be successfully applied to determine the exact shape and position of the debonding in the adhesive joints of composite beams. 相似文献
198.
Magdalena Bisztyga-Szklarz Krzysztof Mech Mateusz Marzec Robert Kalendarev Konrad Szaciowski 《Materials》2021,14(12)
A key challenge for carbon dioxide reduction on Cu-based catalysts is its low faradic efficiency (FE) and selectivity towards higher-value products, e.g., ethylene. The main factor limiting the possibilities of long-term applications of Cu-based gas diffusion electrodes (GDE) is a relatively fast drop in the catalytic activity of copper layers. One of the solutions to the catalyst stability problem may be an in situ reconstruction of the catalyst during the process. It was observed that the addition of a small amount of copper lactate to the electrolyte results in increased Faradaic efficiency for ethylene formation. Moreover, the addition of copper lactate increases the lifetime of the catalytic layer ca. two times and stabilizes the Faradaic efficiency of the electroreduction of CO2 to ethylene at ca. 30%. It can be concluded that in situ deposition of copper through reduction of copper lactate complexes present in the electrolyte provides new, stable, and selective active sites, promoting the reduction of CO2 to ethylene. 相似文献
199.
Marta Babicka Magdalena Wo
niak Kinga Szentner Monika Bartkowiak Barbara Pepliska Krzysztof Dwiecki Sawomir Borysiak Izabela Ratajczak 《Materials》2021,14(12)
Nanocellulose has gained increasing attention during the past decade, which is related to its unique properties and wide application. In this paper, nanocellulose samples were produced via hydrolysis with ionic liquids (1-ethyl-3-methylimidazole acetate (EmimOAc) and 1-allyl-3-methylimidazolium chloride (AmimCl)) from microcrystalline celluloses (Avicel and Whatman) subjected to enzymatic pretreatment. The obtained material was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), and thermogravimetric analysis (TG). The results showed that the nanocellulose had a regular and spherical structure with diameters of 30–40 nm and exhibited lower crystallinity and thermal stability than the material obtained after hydrolysis with Trichoderma reesei enzymes. However, the enzyme-pretreated Avicel had a particle size of about 200 nm and a cellulose II structure. A two-step process involving enzyme pretreatment and hydrolysis with ionic liquids resulted in the production of nanocellulose. Moreover, the particle size of nanocellulose and its structure depend on the ionic liquid used. 相似文献
200.
Within the broad group of Fe non-heme oxidases, our attention was focused on the catechol 1,2- and 2,3-dioxygenases, which catalyze the oxidative cleavage of aromatic rings. A large group of Fe complexes with N/O ligands, ranging from N3 to N2O2S, was developed to mimic the activity of these enzymes. The Fe complexes discussed in this work can mimic the intradiol/extradiol catechol dioxygenase reaction mechanism. Electronic effects of the substituents in the ligand affect the Lewis acidity of the Fe center, increasing the ability to activate dioxygen and enhancing the catalytic activity of the discussed biomimetic complexes. The ligand architecture, the geometric isomers of the complexes, and the substituent steric effects significantly affect the ability to bind the substrate in a monodentate and bidentate manner. The substrate binding mode determines the preferred mechanism and, consequently, the main conversion products. The preferred mechanism of action can also be affected by the solvents and their ability to form the stable complexes with the Fe center. The electrostatic interactions of micellar media, similar to SDS, also control the intradiol/extradiol mechanisms of the catechol conversion by discussed biomimetics. 相似文献