全文获取类型
收费全文 | 992篇 |
免费 | 51篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 22篇 |
妇产科学 | 34篇 |
基础医学 | 113篇 |
口腔科学 | 9篇 |
临床医学 | 95篇 |
内科学 | 226篇 |
皮肤病学 | 29篇 |
神经病学 | 103篇 |
特种医学 | 11篇 |
外科学 | 100篇 |
综合类 | 5篇 |
预防医学 | 128篇 |
眼科学 | 16篇 |
药学 | 89篇 |
中国医学 | 3篇 |
肿瘤学 | 64篇 |
出版年
2023年 | 6篇 |
2022年 | 21篇 |
2021年 | 30篇 |
2020年 | 17篇 |
2019年 | 38篇 |
2018年 | 35篇 |
2017年 | 26篇 |
2016年 | 19篇 |
2015年 | 32篇 |
2014年 | 43篇 |
2013年 | 54篇 |
2012年 | 77篇 |
2011年 | 103篇 |
2010年 | 48篇 |
2009年 | 32篇 |
2008年 | 55篇 |
2007年 | 65篇 |
2006年 | 43篇 |
2005年 | 59篇 |
2004年 | 49篇 |
2003年 | 43篇 |
2002年 | 51篇 |
2001年 | 12篇 |
2000年 | 17篇 |
1999年 | 8篇 |
1998年 | 14篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有1051条查询结果,搜索用时 15 毫秒
1.
2.
3.
Immunoglobulin M Enzyme-Linked Immunosorbent Assay Using Recombinant Polypeptides for Diagnosis of Dengue
下载免费PDF全文
![点击此处可从《Clinical and Vaccine Immunology : CVI》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Elsa Videa Maria Josefina Coloma Flavia Barreto dos Santos Angel Balmaseda Eva Harris 《Clinical and Vaccine Immunology : CVI》2005,12(7):882-884
We demonstrate that a mixture of four recombinant dengue virus E polypeptides corresponding to the N-terminal region of the envelope protein from all serotypes substitutes for standard antigens in two immunoglobulin M enzyme-linked immunosorbent assay formats with 100% concordance, making these polypeptides a useful and accessible reagent for serological diagnosis of dengue in endemic countries. 相似文献
4.
Tsai JC de Groot L Pinon JD Iacono KT Phillips JJ Seo SH Lavi E Weiss SR 《Virology》2003,312(2):369-380
Targeted recombination was carried out to select mouse hepatitis viruses (MHVs) in a defined genetic background, containing an MHV-JHM spike gene encoding either three heptad repeat 1 (HR1) substitutions (Q1067H, Q1094H, and L1114R) or L1114R alone. The recombinant virus, which expresses spike with the three substitutions, was nonfusogenic at neutral pH. Its replication was significantly inhibited by lysosomotropic agents, and it was highly neuroattenuated in vivo. In contrast, the recombinant expressing spike with L1114R alone mediated cell-to-cell fusion at neutral pH and replicated efficiently despite the presence of lysosomotropic agents; however, it still caused only subclinical morbidity and no mortality in animals. Thus, both recombinant viruses were highly attenuated and expressed viral antigen which was restricted to the olfactory bulbs and was markedly absent from other regions of the brains at 5 days postinfection. These data demonstrate that amino acid substitutions, in particular L1114R, within HR1 of the JHM spike reduced the ability of MHV to spread in the central nervous system. Furthermore, the requirements for low pH for fusion and viral entry are not prerequisites for the highly attenuated phenotype. 相似文献
5.
Novel vectors for the expression of antibody molecules using variable regions generated by polymerase chain reaction. 总被引:20,自引:0,他引:20
A new family of vectors has been produced which facilitates the cloning and expression of immunoglobulin variable regions cloned by polymerase chain reaction (PCR). The vectors are designed to express the cloned variable regions joined to human constant regions and take advantage of priming in the leader sequence so that no amino acid changes will be introduced into the mature antibody molecule. Both the heavy chain and light chain vectors utilize a murine VH promoter provided with an EcoRV restriction site so that the amplified variable regions can be directly cloned into a functional promoter. For the heavy chain an NheI restriction site has been generated at the first two amino acids of CH1 and the cloned leader and variable region are fused directly to the CH1 domain of the constant region. When the leader and variable regions of the light chain were fused directly to C kappa, no expression was observed. Therefore the light chain expression vector was designed with a SalI restriction site for cloning into a splice junction 3' of the variable region; VL then is joined to C kappa by splicing. Both vectors direct the expression of functional, fully assembled immunoglobulin molecules with the expected molecular weight. Use of redundant oligomers to prime the PCR permits the cloning and expression of recombinant antibodies without any prior information as to their sequence and makes it possible to rapidly generate recombinant antibodies from any monoclonal antibody producing cell line. 相似文献
6.
A BrdU-Hoechst 33258 treatment of living cells, which selectively induced condensation-inhibition of G-band chromatin in human and Chinese hamster chromosomes, is presented. As a consequence mitotic chromosomes showed high resolution R-banding patterns when examined by light and electron microscopy. Besides each whole chromosome identification, this procedure also permitted the electron microscopic study of specific structures, such as satellites, secondary constrictions, telomeres, centromeres, as well as G and R bands, some of them not visible by light microscopy. We have also observed that the chromatin of G and R bands behave as blocks of chromatin condensation and that G-band chromatin develops condensation along G2. Under the BrdU-Hoechst 33258 treatment, chromatin fibers seem to invert their spontaneous pattern of condensation within the chromosomes. 相似文献
7.
Comparison of the costs and recovery profiles of three anesthetic techniques for ambulatory anorectal surgery 总被引:7,自引:0,他引:7
BACKGROUND: Given the current practice environment, it is important to determine the anesthetic technique with the highest patient acceptance and lowest associated costs. The authors compared three commonly used anesthetic techniques for anorectal procedures in the ambulatory setting. METHODS: Ninety-three consenting adult outpatients undergoing anorectal surgery were randomly assigned to one of three anesthetic treatment groups: group 1 received local infiltration with a 30-ml mixture containing 15 ml lidocaine, 2%, and 15 ml bupivacaine, 0.5%, with epinephrine (1:200,000) in combination with intravenous sedation using a propofol infusion, 25-100 microg. kg-1. min-1; group 2 received a spinal subarachnoid block with a combination of 30 mg lidocaine and 20 microg fentanyl with midazolam, 1-2-mg intravenous bolus doses; and group 3 received general anesthesia with 2.5 mg/kg propofol administered intravenously and 0.5-2% sevoflurane in combination with 65% nitrous oxide. In groups 2 and 3, the surgeon also administered 10 ml of the previously described local anesthetic mixture at the surgical site before the skin incision. RESULTS: The mean costs were significantly decreased in group 1 ($69 +/- 20 compared with $104 +/- 18 and $145 +/- 25 in groups 2 and 3, respectively) because both intraoperative and recovery costs were lowest (P < 0.05). Although the surgical time did not differ among the three groups, the anesthesia time and times to oral intake and home-readiness were significantly shorter in group 1 (vs. groups 2 and 3). There was no significant difference among the three groups with respect to the postoperative side effects or unanticipated hospitalizations. However, the need for pain medication was less in groups 1 and 2 (19% and 19% vs. 45% for group 3; P < 0.05). Patients in group 1 had no complaints of nausea (vs. 3% and 26% in groups 2 and 3, respectively). More patients in group 1 (68%) were highly satisfied with the care they received than in groups 2 (58%) and 3 (39%). CONCLUSIONS: The use of local anesthesia with sedation is the most cost-effective technique for anorectal surgery in the ambulatory setting. 相似文献
8.
Rebeca Rodríguez‐Veiga Pau Montesinos Estefanía García Blanca Boluda Rafael Rojas Josefina Serrano David Martínez‐Cuadrn Carmen Martín Jaime Sanz Salvador Tabares Jos L. Piana Ignacio Lorenzo Juan Montoro Miguel Salavert Javier Pemn Isidro Jarque Pilar Solves Guillermo F. Sanz Antonio Torres Miguel A. Sanz 《Mycoses》2019,62(5):418-427
9.
Daniel Villarreal Jyoti Sharma Maria Josefina Arellano-Jimenez Orlando Auciello Elida de Obaldía 《Materials》2022,15(17)
This article shows the results of experiments to grow Nitrogen incorporated ultrananocrystalline diamond (N-UNCD) films on commercial natural graphite (NG)/Cu anodes by hot chemical vapor deposition (HFCVD) using a gas mixture of Ar/CH4/N2/H2. The experiments focused on studying the effect of the pressure in the HFCVD chamber, filament-substrate distance, and temperature of the substrate. It was found that a substrate distance of 3.0 cm and a substrate temperature of 575 C were optimal to grow N-UNCD film on the graphite surface as determined by Raman spectroscopy, SEM, and TEM imaging. XPS analysis shows N incorporation through the film. Subsequently, the substrate surface temperature was increased using a heater, while keeping the substrate-filament distance constant at 3.0 cm. In this case, Raman spectra and SEM images of the substrate surface showed a major composition of graphite in the film as the substrate-surface temperature increased. Finally, the process pressure was increased to 10 Torr where it was seen that the growth of N-UNCD film occurred at 2.0 cm at a substrate temperature of 675 C. These results suggest that as the process pressure increases a smaller substrate-filament distance and consequently a higher substrate surface temperature can still enable the N-UNCD film growth by HFCVD. This effect is explained by a mean free path analysis of the main precursors H2 and CH3 molecules traveling from the filament to the surface of the substrate The potential impact of the process developed to grow electrically conductive N-UNCD films using the relatively low-cost HFCVD process is that this process can be used to grow N-UNCD films on commercial NG/Cu anodes for Li-ion batteries (LIBs), to enable longer stable capacity energy vs. charge/discharge cycles. 相似文献
10.
Emilie Brard Christoph Rllig Sarah Bertoli Arnaud Pigneux Suzanne Tavitian Michael Kramer Hubert Serve Martin Bornhuser Uwe Platzbecker Carsten Müller-Tidow Claudia D. Baldus David Martínez-Cuadrn Josefina Serrano Pilar Martínez-Snchez Eduardo Rodríguez Arbolí Cristina Gil Juan Bergua Teresa Bernal Adolfo de la Fuente Burguera Eric Delabesse Audrey Bidet Pierre-Yves Dumas Pau Montesinos Christian Rcher 《Blood cancer journal》2022,12(7)
In a context of therapeutic revolution in older adults with AML, it is becoming increasingly important to select patients for the various treatment options by taking account of short-term efficacy and toxicity as well as long-term survival. Here, the data from three European registries for 1,199 AML patients aged 70 years or older treated with intensive chemotherapy were used to develop a prognostic scoring system. The median follow-up was 50.8 months. In the training set of 636 patients, age, performance status, secondary AML, leukocytosis, and cytogenetics, as well as NPM1 mutations (without FLT3-ITD), were all significantly associated with overall survival, albeit not to the same degree. These factors were used to develop a score that predicts long-term overall survival. Three risk-groups were identified: a lower, intermediate and higher-risk score with predicted 5-year overall survival (OS) probabilities of ≥12% (n = 283, 51%; median OS = 18 months), 3–12% (n = 226, 41%; median OS = 9 months) and <3% (n = 47, 8%; median OS = 3 months), respectively. This scoring system was also significantly associated with complete remission, early death and relapse-free survival; performed similarly in the external validation cohort (n = 563) and showed a lower false-positive rate than previously published scores. The European Scoring System ≥70, easy for routine calculation, predicts long-term survival in older AML patients considered for intensive chemotherapy.Subject terms: Acute myeloid leukaemia, Risk factors 相似文献