全文获取类型
收费全文 | 39434篇 |
免费 | 2636篇 |
国内免费 | 15篇 |
出版年
2023年 | 195篇 |
2022年 | 384篇 |
2021年 | 920篇 |
2020年 | 529篇 |
2019年 | 684篇 |
2018年 | 952篇 |
2017年 | 804篇 |
2016年 | 1334篇 |
2015年 | 2026篇 |
2014年 | 2182篇 |
2013年 | 2986篇 |
2012年 | 3423篇 |
2011年 | 3253篇 |
2010年 | 1994篇 |
2009年 | 1719篇 |
2008年 | 2442篇 |
2007年 | 2341篇 |
2006年 | 2098篇 |
2005年 | 1885篇 |
2004年 | 1774篇 |
2003年 | 1724篇 |
2002年 | 1549篇 |
2001年 | 348篇 |
2000年 | 259篇 |
1999年 | 337篇 |
1998年 | 390篇 |
1997年 | 270篇 |
1996年 | 261篇 |
1995年 | 255篇 |
1994年 | 244篇 |
1993年 | 241篇 |
1992年 | 169篇 |
1991年 | 170篇 |
1990年 | 179篇 |
1989年 | 134篇 |
1988年 | 136篇 |
1987年 | 117篇 |
1986年 | 91篇 |
1985年 | 124篇 |
1984年 | 113篇 |
1983年 | 85篇 |
1982年 | 93篇 |
1981年 | 87篇 |
1980年 | 85篇 |
1979年 | 89篇 |
1978年 | 49篇 |
1977年 | 56篇 |
1975年 | 45篇 |
1973年 | 54篇 |
1972年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Rosane Aparecida Ribeiro Sandra Lucinei Balbo Letícia Prates Roma Rafael Ludemann Camargo Luiz Felipe Barella Emerielle Cristine Vanzela Paulo Cesar de Freitas Mathias Everardo Magalhães Carneiro Antonio Carlos Boschero Maria Lúcia Bonfleur 《Molecular biology reports》2013,40(7):4521-4528
Monosodium glutamate-obese rats are glucose intolerant and insulin resistant. Their pancreatic islets secrete more insulin at increasing glucose concentrations, despite the possible imbalance in the autonomic nervous system of these rats. Here, we investigate the involvement of the cholinergic/protein kinase (PK)-C and PKA pathways in MSG β-cell function. Male newborn Wistar rats received a subcutaneous injection of MSG (4 g/kg body weight (BW)) or hyperosmotic saline solution during the first 5 days of life. At 90 days of life, plasma parameters, islet static insulin secretion and protein expression were analyzed. Monosodium glutamate rats presented lower body weight and decreased nasoanal length, but had higher body fat depots, glucose intolerance, hyperinsulinemia and hypertrigliceridemia. Their pancreatic islets secreted more insulin in the presence of increasing glucose concentrations with no modifications in the islet-protein content of the glucose-sensing proteins: the glucose transporter (GLUT)-2 and glycokinase. However, MSG islets presented a lower secretory capacity at 40 mM K+ (P < 0.05). The MSG group also released less insulin in response to 100 μM carbachol, 10 μM forskolin and 1 mM 3-isobutyl-1-methyl-xantine (P < 0.05, P < 0.0001 and P < 0.01). These effects may be associated with a the decrease of 46 % in the acetylcholine muscarinic type 3 (M3) receptor, and a reduction of 64 % in PKCα and 36 % in PKAα protein expressions in MSG islets. Our data suggest that MSG islets, whilst showing a compensatory increase in glucose-induced insulin release, demonstrate decreased islet M3/PKC and adenylate cyclase/PKA activation, possibly predisposing these prediabetic rodents to the early development of β-cell dysfunction. 相似文献
982.
Elisabetta Teodolinda Maria Mapelli A. Cerri C. Bombonato S. Menni 《Mycopathologia》2013,176(3-4):243-246
Tinea capitis (TC) is the most common type of dermatophytosis in children. The epidemiology of TC depends on the geographical areas, and it changes over time. The aim of the study is to determine the incidence of TC and to identify the causative species in children observed at Dermatology Outpatient Department of the University of Milan, Italy, between January 2004 and December 2011. Four hundred and eighty-six children with suspected dermatomycosis were observed; TC was the most prevalent dermatomycoses with 86 cases. The most common isolated dermatophyte in scalp lesions was Trichophyton violaceum with 33 cases. The most recent epidemiological Italian studies still show zoophilic fungi as primary cause of TC. We are the first medical team in Italy to demonstrate a dominance of anthropophilic fungi, in particular T. violaceum. 相似文献
983.
Marcela A. Garabalino Elisa M. Heber Andrea Monti Hughes Sara J. González Ana J. Molinari Emiliano C. C. Pozzi Susana Nievas Maria E. Itoiz Romina F. Aromando David W. Nigg William Bauer Verónica A. Trivillin Amanda E. Schwint 《Radiation and environmental biophysics》2013,52(3):351-361
Boron neutron capture therapy (BNCT) is based on selective accumulation of 10B carriers in tumor followed by neutron irradiation. We previously proved the therapeutic success of BNCT mediated by the boron compounds boronophenylalanine and sodium decahydrodecaborate (GB-10) in the hamster cheek pouch oral cancer model. Based on the clinical relevance of the boron carrier sodium borocaptate (BSH) and the knowledge that the most effective way to optimize BNCT is to improve tumor boron targeting, the specific aim of this study was to perform biodistribution studies of BSH in the hamster cheek pouch oral cancer model and evaluate the feasibility of BNCT mediated by BSH at nuclear reactor RA-3. The general aim of these studies is to contribute to the knowledge of BNCT radiobiology and optimize BNCT for head and neck cancer. Sodium borocaptate (50 mg 10B/kg) was administered to tumor-bearing hamsters. Groups of 3–5 animals were killed humanely at nine time-points, 3–12 h post-administration. Samples of blood, tumor, precancerous pouch tissue, normal pouch tissue and other clinically relevant normal tissues were processed for boron measurement by optic emission spectroscopy. Tumor boron concentration peaked to therapeutically useful boron concentration values of 24–35 ppm. The boron concentration ratio tumor/normal pouch tissue ranged from 1.1 to 1.8. Pharmacokinetic curves showed that the optimum interval between BSH administration and neutron irradiation was 7–11 h. It is concluded that BNCT mediated by BSH at nuclear reactor RA-3 would be feasible. 相似文献
984.
985.
986.
Mutations in neuronal voltage-gated sodium channel genes SCN1A, SCN2A, and SCN3A may play an important role in the etiology of neurological diseases and psychiatric disorders, besides various types of epilepsy. Here we describe a 3-year-old boy with autistic features, language delay, microcephaly and no history of seizures. Array-CGH analysis revealed an interstitial deletion of ~ 291.9 kB at band 2q24.3 disrupting the entire SCN2A gene and part of SCN3A. We discuss the effects of haploinsufficiency of SCN2A and SCN3A on the genetic basis of neurodevelopmental and neurobehavioral disorders and we propose that this haploinsufficiency may be associated not only with epilepsy, but also with autistic features. 相似文献
987.
Nungki Anggorowati Yoshihiko Yano Yanri Wijayanti Subronto Takako Utsumi Didik Setyo Heriyanto Deshinta Putri Mulya Hanggoro Tri Rinonce Dewiyani Indah Widasari Maria Inge Lusida Soetjipto Yoshitake Hayashi 《Microbiology and immunology》2013,57(4):298-308
GB virus C (GBV‐C), a human virus of the Flaviviridae family that is structurally and epidemiologically closest to hepatitis C virus (HCV), has been reported to confer beneficial outcomes in HIV‐positive patients. However, the prevalence of GBV‐C in HIV‐positive individuals in Indonesia is unknown. Since GBV‐C is more prevalent in anti‐HCV positive patients than in anti‐HCV negative subjects, transmission of GBV‐C and HCV could be by the same method. This study examined the prevalence and molecular characteristics of GBV‐C infection in HIV patients in Yogyakarta, Indonesia. The prevalence of GBV‐C among HIV patients (n = 125, median age 31 years) based on the 5′UTR region was 111/125 (88.8%), including 39/48 (81.3%) and 72/77 (93.5%) HIV‐infected patients with and without HCV infection, respectively. GBV‐C isolates were of genotype 2a, 3 and 6 in 58.3%, 12.6% and 28.4% of patients, respectively. Patients with genotype 3 were significantly younger than those with genotypes 2a or 6 (P = 0.001 and P = 0.012, respectively). Genotypes 3 and 6 were significantly associated with injection drug use (P = 0.004 and P = 0.002, respectively) and HCV co‐infection (P < 0.001 for both genotypes), indicating a shared transmission route with HCV. In conclusion, the prevalence of GBV‐C among HIV‐positive patients in Indonesia is high, and three genotypes were detected, namely genotype 2a, 3 and 6. 相似文献
988.
989.
Glutaraldehyde (GTA) is a widely used biocide due to its high effectiveness. The experimental work reported here was carried out to assess the effectiveness of GTA in controlling biofilms formed by Pseudomonas fluorescens on stainless steel slides, and to compare efficacy against both planktonic and sessile micro‐rganisms. The tests were performed using two concentrations of GTA (50 and 100mg 1‐1), biofilms of two ages (7 and 15 d), several pH values (5,7 and 9) and a range of exposure times (from 0 (control) to 1,3,7 and 24 h). The action of GTA on biofilm and planktonic populations was assessed by means of activity tests, zeta potential, and the wet weight of the biofilms. Biofilms were not completely removed after treatment with GTA in any of the conditions studied. The higher GTA concentration was more effective in reducing the bacterial activity of the biofilm. The biocide proved to be more effective for longer exposure times. GTA showed good antimicrobial activity against P. fluorescens in suspension, with higher activity at pH 9. The findings of this study suggest that when GTA is used to control biofilms, it reacts with one of the components of the matrix, the proteins, thereby reducing its antimicrobial action. 相似文献
990.
Luís Roque Noélia Duarte Maria Rosário Bronze Catarina Garcia Julia Alopaeus Jesus Molpeceres 《Biofouling》2013,29(8):880-892
AbstractGlycyrrhiza glabra L. is considered an important source of bioactive compounds. This study aimed at the development of an efficient solution for the treatment of oral candidiasis. Several extracts of Glycyrrhiza glabra L. were prepared using different solvents and their potential in vitro antifungal activity was assessed. Ethanolic extracts showed the most promising results against C. albicans. This extract was incorporated into mucoadhesive nanoparticles (PLA, PLGA and alginate), which were further included in an oral gel, an oral film and a toothpaste, respectively. The results showed that nanoparticles were successfully produced, presenting a mean size among 100–900?nm with high encapsulation efficiency. In vitro studies showed that the most bioadhesive formulation was the oral film with extract-loaded PLGA nanoparticles, followed by the toothpaste with extract-loaded alginate nanoparticles and the oral gel with extract-loaded PLA nanoparticles. 相似文献