全文获取类型
收费全文 | 3486篇 |
免费 | 188篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 79篇 |
儿科学 | 93篇 |
妇产科学 | 79篇 |
基础医学 | 536篇 |
口腔科学 | 57篇 |
临床医学 | 288篇 |
内科学 | 750篇 |
皮肤病学 | 76篇 |
神经病学 | 363篇 |
特种医学 | 119篇 |
外科学 | 225篇 |
综合类 | 24篇 |
预防医学 | 280篇 |
眼科学 | 64篇 |
药学 | 417篇 |
中国医学 | 10篇 |
肿瘤学 | 237篇 |
出版年
2024年 | 4篇 |
2023年 | 48篇 |
2022年 | 186篇 |
2021年 | 271篇 |
2020年 | 91篇 |
2019年 | 142篇 |
2018年 | 157篇 |
2017年 | 115篇 |
2016年 | 131篇 |
2015年 | 126篇 |
2014年 | 168篇 |
2013年 | 220篇 |
2012年 | 288篇 |
2011年 | 281篇 |
2010年 | 149篇 |
2009年 | 129篇 |
2008年 | 168篇 |
2007年 | 220篇 |
2006年 | 207篇 |
2005年 | 175篇 |
2004年 | 147篇 |
2003年 | 111篇 |
2002年 | 100篇 |
2001年 | 11篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有3697条查询结果,搜索用时 31 毫秒
991.
Aleksandra Ledwon Piotr Szeleszczuk Zofia Zwolska Ewa Augustynowicz-Kopec Rafal Sapierzynski Marcin Kozak 《Avian pathology》2008,37(1):59-64
The aim of the present study was to determine the susceptibility of budgerigars (Melopsittacus undulatus) to infections with different Mycobacterium species. For inoculations the following Mycobacterium species were used: Mycobacterium avium subsp. avium, Mycobacterium bovis subsp. bovis, Mycobacterium tuberculosis subsp. tuberculosis, Mycobacterium intracellulare and M. fortuitum subsp. fortuitum. The bacterial suspension was administrated intramuscularly and all the birds were monitored for 70 days starting from the day of inoculation. During the experiment clinical examination, X-ray scans, plate agglutination tests, tuberculin tests, faeces smear preparations and culture of mycobacteria were performed. The study showed that M. bovis subsp. bovis was the most pathogenic Mycobacterium species for budgerigars. After inoculation, the bacilli induced tuberculosis-typical, clinical signs and necropsy findings. In two out of six birds infected with M. bovis subsp. bovis radiological changes were also visible. Birds inoculated with other Mycobacterium species did not show any typical symptoms of infection, and only the results of histopathological and bacteriological examinations indicated the presence of infection. 相似文献
992.
Stojanović M Inić-Kanada A Popović Z Zivković I Dimitrijević L 《Immunology letters》2004,94(1-2):123-133
Antibodies (Abs) (IgM, IgA, IgG and IgG subclasses) specific for several uropathogenic strains (Escherichia coli, Pseudomonas sp. and Klebsiella sp.) as well as anti-phospholipids, anti-beta2-glycoprotein I and anti-laminin antibodies were analyzed in the sera of 20 patients with long-lasting uncomplicated recurrent infections of the lower urinary tract who underwent immunization treatment with a mixture of heat-inactivated bacteria. Immunization had a dual effect: a marked prolongation of the infection-free period in more than half of tested patients (which could be related to the profiles of anti-bacterial antibodies), and the induction of a significant decrease in autoreactivity. The results obtained showed that prolonged infections resulted in a significant rise in IgG specific for phospholipids, beta2-glycoprotein I and mouse laminin. However, irrespective of the effect on urinary tract infection per se, immunization induced a noticeable decrease in reactivity toward those antigens (Ag). The most abundant autoantibodies prior to immunization treatment were of IgG2 subclass. A statistically significant decrease in phospholipid specific antibodies belonging to this subclass, and in the concentration of Y7 cross-reactive idiotope, registered only in the responder group; this indicates the significance of natural antibody pool involvement in a proper anti-bacterial immune response. 相似文献
993.
994.
Danijela Smiljani Aleksandra Dakovi Milena Obradovi Milica Oegovi Francesco Izzo Chiara Germinario Bruno de Gennaro 《Materials》2021,14(24)
This work aimed to test composites (surfactant modified zeolites prepared by treatment of natural zeolites—clinoptilolite (IZ CLI) and/or phillipsite (PHIL75)-rich tuffs with two different amounts of cationic surfactants: cetylpyridinium chloride (CPyCl) and Arquad® 2HT-75 (ARQ)) for the adsorption of salicylic acid (SA)—a common contaminant of emerging concern. Adsorption of SA was studied at different initial drug concentrations (in the range of 2–100 mg/L) in water solution. The Langmuir isotherm model showed the highest adsorption was achieved by bilayer composite of IZ CLI and CPyCl—around 11 mg/g. Kinetic runs were performed by using the initial drug concentration of 20 mg/L in the time interval from 0 to 75 min and pseudo-second order had good correlation with experimental data. The influence of the four different temperatures on the SA adsorption was also investigated and thermodynamic parameters suggested that the adsorption drug onto composites is an exothermic and nonspontaneous process, followed by the decrease of randomness at the solid/liquid interface during the adsorption. Zeta potential and Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) had been performed for the characterization of composites after adsorption of SA confirming the presence of the drug at composite surfaces. 相似文献
995.
Aleksandra Glogowska Thatchawan Thanasupawat Jason Beiko Marshall Pitz Sabine HombachKlonisch Thomas Klonisch 《Molecular oncology》2022,16(2):368
C1q tumor necrosis factor‐related peptide 8 (CTRP8) is the least studied member of the C1Q‐TNF‐related peptide family. We identified CTRP8 as a ligand of the G protein‐coupled receptor relaxin family peptide receptor 1 (RXFP1) in glioblastoma multiforme (GBM). The CTRP8‐RXFP1 ligand–receptor system protects human GBM cells against the DNA‐alkylating damage‐inducing temozolomide (TMZ), the drug of choice for the treatment of patients with GBM. The DNA protective role of CTRP8 was dependent on a functional RXFP1‐STAT3 signaling cascade and targeted the monofunctional glycosylase N‐methylpurine DNA glycosylase (MPG) for more efficient base excision repair of TMZ‐induced DNA‐damaged sites. CTRP8 also improved the survival of GBM cells by upregulating anti‐apoptotic BCl‐2 and BCL‐XL. Here, we have identified Janus‐activated kinase 3 (JAK3) as a novel member of a novel CTRP8‐RXFP1‐JAK3‐STAT3 signaling cascade that caused an increase in cellular protein content and activity of the small Rho GTPase Cdc42. This is associated with significant F‐actin remodeling and increased GBM motility. Cdc42 was critically important for the upregulation of the actin nucleation complex N‐Wiskott–Aldrich syndrome protein/Arp3/4 and actin elongation factor profilin‐1. The activation of the RXFP1‐JAK3‐STAT3‐Cdc42 axis by both RXFP1 agonists, CTRP8 and relaxin‐2, caused extensive filopodia formation. This coincided with enhanced activity of ezrin, a key factor in tethering F‐actin to the plasma membrane, and inhibition of the actin filament severing activity of cofilin. The F‐actin remodeling and pro‐migratory activities promoted by the novel RXFP1‐JAK3‐STAT3‐Cdc42 axis were blocked by JAK3 inhibitor tofacitinib and STAT3 inhibitor STAT3 inhibitor VI. This provides a new rationale for the design of JAK3 and STAT3 inhibitors with better brain permeability for clinical treatment of the pervasive brain invasiveness of GBM. 相似文献
996.
Aleksandra Dbska Piotr Gwo
dziewicz Andrzej Seruga Xavier Balandraud Jean-Franois Destrebecq 《Materials》2022,15(3)
This paper deals with the mechanical behavior of hollow concrete cylinders prestressed with nickel-titanium (Ni-Ti)-shape memory alloy (SMA) wires wound around them. Prestresses can be created by the thermal activation of the memory effect of SMA wire placed on the outer surface of concrete cylinders. In order to assess the stress level in concrete, a model was used to analyze the thermal stresses in the concrete shell resulting from a temperature gradient in the thickness. Another model was used to calculate the circular concentric loading applied by the wound wire resulting from the impairment of its memory effect by the concrete cylinder. Finally, longitudinal compression tests were performed on the prestressed hollow cylinders. Longitudinal and circumferential strains were measured using gauges located on the surfaces of the hollow cylinders. The tests were performed almost one year after the application of prestressing by means of Ni-Ti SMA wire, confirming that the residual stress in the wire remained present. It may therefore be concluded that the prestressing of concrete elements designed with the use of Ni-Ti SMA material is effective for a long time. 相似文献
997.
Porcine respirovirus 1 (PRV1) is also known as porcine parainfluenza virus 1 (PPIV1). The prevalence and the role of PRV1 infections for pig health is largely unknown. In order to assess the PRV1 prevalence in Poland, nasal swabs and oral fluids collected from pigs from 30 farms were examined with RT real-time PCR. Additionally, IAV and PRRSV infection statuses of PRV1-positive samples were examined. The results showed that the virus is highly prevalent (76.7% farms positive) and different patterns of PRV1 circulation in herds with mild–moderate respiratory disease were observed. Co-infections with IAV and PRRSV were infrequent and detected in 8 (23.5%) and 4 (11.8%) out of 34 PRV1-positive nasal swab pools from diseased pens, respectively. In one pen PRV1, IAV, and PRRSV were detected at the same time. Interestingly, PRV1 mean Ct value in samples with co-infections was significantly lower (29.8 ± 3.1) than in samples with a single PRV1 infection (32.5 ± 3.6) (p < 0.05), which suggested higher virus replication in these populations. On the other hand, the virus detection in pig populations exhibiting respiratory clinical signs, negative for PRRSV and IAV, suggests that PRV1 should be involved in differential diagnosis of respiratory problems. 相似文献
998.
Linh Trinh Krzysztof Bienkowski Piotr Wrbel Marcin Pisarek Aleksandra Parzuch Nabila Nawaz Renata Solarska 《Materials》2022,15(3)
The CuO@CuFe2O4 core–shell structure represents a new family of photocatalysts that can be used as photoelectrodes that are able to produce hydrogen under a broad spectrum of visible light. Herein, we report a novel approach for the production of this active film by the thermal conversion of CuFe Prussian Blue Analogues. The outstanding photoelectrochemical properties of the photocathodes of CuO@CuFe2O4 were studied with the use of combinatory photo-electrochemical instrumental techniques which proved that the electrodes were stable over the whole water photolysis run under relatively positive potentials. Their outstanding performance was explained by the coupling of two charge transfer mechanisms occurring in core–shell architectures. 相似文献
999.
A. Hasan Howlader Sazzad H. Suzol Venkadesh Sarkarai Nadar Adriana Emilce Galvn Aleksandra Nedovic Predrag Cudic Barry P. Rosen Masafumi Yoshinaga Stanislaw F. Wnuk 《RSC advances》2021,11(56):35600
We report two routes of chemical synthesis of arsinothricin (AST), the novel organoarsenical antibiotic. One is by condensation of the 2-chloroethyl(methyl)arsinic acid with acetamidomalonate, and the second involves reduction of the N-acetyl protected derivative of hydroxyarsinothricin (AST-OH) and subsequent methylation of a trivalent arsenic intermediate with methyl iodide. The enzyme AST N-acetyltransferase (ArsN1) was utilized to purify l-AST from racemic AST. This chemical synthesis provides a source of this novel antibiotic for future drug development.Arsinothricin is prepared from 2-chloroethyl(methyl)arsinic acid or by reduction of N-acetyl protected derivative of hydroxyarsinothricin and methylation with methyl iodide. 相似文献
1000.