全文获取类型
收费全文 | 1149篇 |
免费 | 58篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 23篇 |
妇产科学 | 28篇 |
基础医学 | 161篇 |
口腔科学 | 8篇 |
临床医学 | 103篇 |
内科学 | 396篇 |
皮肤病学 | 5篇 |
神经病学 | 57篇 |
特种医学 | 23篇 |
外科学 | 161篇 |
综合类 | 5篇 |
预防医学 | 68篇 |
眼科学 | 40篇 |
药学 | 67篇 |
中国医学 | 19篇 |
肿瘤学 | 39篇 |
出版年
2023年 | 10篇 |
2022年 | 20篇 |
2021年 | 64篇 |
2020年 | 19篇 |
2019年 | 49篇 |
2018年 | 57篇 |
2017年 | 24篇 |
2016年 | 30篇 |
2015年 | 40篇 |
2014年 | 52篇 |
2013年 | 58篇 |
2012年 | 80篇 |
2011年 | 86篇 |
2010年 | 30篇 |
2009年 | 26篇 |
2008年 | 55篇 |
2007年 | 57篇 |
2006年 | 51篇 |
2005年 | 49篇 |
2004年 | 49篇 |
2003年 | 33篇 |
2002年 | 44篇 |
2001年 | 26篇 |
2000年 | 32篇 |
1999年 | 25篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1992年 | 13篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 4篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1967年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有1210条查询结果,搜索用时 15 毫秒
41.
Arámbula Cosío F Márquez Flores JA Padilla Castañeda MA Solano S Tato P 《Medical & biological engineering & computing》2005,43(5):672-677
An automatic colour image segmentation and cell counting software system has been developed for immunocytochemical analysis
of stained tissue samples. The system was designed to count the total number of positive and negative cells in tissue samples
treated with cytokine DNA probes from pigs naturally parasitised with Taenia solium metacestodes, using in situ hybridisation.
A reaction index was calculated as the ratio of the number of cells with a positive reaction to the total number of cells
(positives plus negatives) for each of five different probes. The objectives of automatic counting were to improve the reproducibility
of the analysis and reduce the processing time of large image batches. A fast KNN classifier was used for colour segmentation.
Watershed segmentation combined with edge detection was used to isolate individual cells that were then automatically labelled,
using the results of the corresponding colour segmented image. Validation was performed on 122 non-training digital images
with a total of 1069 positive cells and 1459 negative cells, with the following results: a mean true positive rate of 90.2%
for positive cells and a mean true positive rate of 85.4% for negative cells. The corresponding mean false positive rates
were 9.6% and 6.6%. The mean reaction index error of the automatic analysis was 5.35%. The processing of each digital image
took 10 s on a Pentium IV PC. 相似文献
42.
43.
Juan Miguel Esteban Alberto Martín-Serra Ceferino Varón-González Alejandro Pérez-Ramos David Velasco Francisco J. Pastor Borja Figueirido 《Journal of anatomy》2020,237(6):1087-1102
The sacrum is a key piece of the vertebrate skeleton, since it connects the caudal region with the presacral region of the vertebral column and the hind limbs through the pelvis. Therefore, understanding its form and function is of great relevance in vertebrate ecomorphology. However, it is striking that morphometric studies that quantify its morphological evolution in relation to function are scarce. The main goal of this study is to investigate the morphological evolution of the sacrum in relation to its function in the mammalian order Carnivora, using three-dimensional (3D) geometric morphometrics. Principal component analysis under a phylogenetic background indicated that changes in sacrum morphology are mainly focused on the joint areas where it articulates with other parts of the skeleton allowing resistance to stress at these joints caused by increasing muscle loadings. In addition, we demonstrated that sacrum morphology is related to both the length of the tail relativised to the length of the body, and the length of the body relativised to body mass. We conclude that the sacrum in carnivores has evolved in response to the locomotor requirements of the species analysed, but in locomotion, each family has followed alternative morphological solutions to address the same functional demands. 相似文献
44.
Marianne Boysen Marisé Borja Catalina del Moral Oscar Salazar Victor Rubio 《Current genetics》1996,29(2):174-181
The relatedness of nine isolates ofRhizoctonia solani, belonging to anastomosis group (AG) 4, and one isolate of AG1 was determined by comparative sequence analysis based on direct sequencing of PCR-amplified ribosomal DNA [the internal transcribed spacer (ITS) region and the 5.8 s ribosomal DNA]. The 5.8s rDNA is completely conserved, but both ITS regions show variation among strains. AG1 was an outgroup based on anastomosis ability and RFLP analyses. Phylogenetic analyses based on the ITS sequences suggest that the analyzed AG4 strains can be divided into three groups that correlate with habitat and virulence. 相似文献
45.
Fantin S Maspero J Bisbal C Agache I Donado E Borja J Mola O Izquierdo I;international Rupatadine study group 《Allergy》2008,63(7):924-931
Background: With the current increasing incidence of allergies worldwide, new treatments showing efficacy and long term safety are needed for chronic conditions such as persistent allergic rhinitis (PER). New generation H1-antihistamines have demonstrated anti-allergic properties, which could possibly enhance their effectiveness in long-term periods of treatment.
Objective: To investigate the efficacy of rupatadine, in controlling symptoms of PER over a 12-week period.
Methods: A randomized, double blind, parallel-group, placebo-controlled study was carried out in patients aged older than 12 years with PER. Main inclusion criteria were: instantaneous total symptom score (i6TSS) ≥45, nasal obstruction score ≤12, and overall assessment of PER ≥2 as moderate during the first visit. The primary efficacy endpoint was the 12-week average change from baseline of the patients' i6TSS.
Results: In all, 736 patients were selected. Of them, 543 (73.8%) were randomized in three different groups: placebo ( n = 185), cetirizine ( n = 175) and rupatadine ( n = 183). Rupatadine ( P = 0.008) but not cetirizine ( P = 0.07) statistically reduced the baseline i6TSS vs placebo (47.8%, 44.7% and 38.8%, respectively), after 12 weeks. Onset of action was observed at the first 24 h for both treatments (rupatadine vs placebo, P = 0.013; cetirizine vs placebo, P = 0.015). Furthermore, instantaneous total nasal symptoms score (iTNSS) (including nasal blockage) mean change from baseline showed a significant reduction with rupatadine 10 mg in comparison with placebo, along all treatment duration of 12 weeks. Study treatments were well tolerated.
Conclusion: Rupatadine significantly relieves symptoms of PER, providing a rapid onset of action and maintains its effects over a long period of 12-weeks. 相似文献
Objective: To investigate the efficacy of rupatadine, in controlling symptoms of PER over a 12-week period.
Methods: A randomized, double blind, parallel-group, placebo-controlled study was carried out in patients aged older than 12 years with PER. Main inclusion criteria were: instantaneous total symptom score (i6TSS) ≥45, nasal obstruction score ≤12, and overall assessment of PER ≥2 as moderate during the first visit. The primary efficacy endpoint was the 12-week average change from baseline of the patients' i6TSS.
Results: In all, 736 patients were selected. Of them, 543 (73.8%) were randomized in three different groups: placebo ( n = 185), cetirizine ( n = 175) and rupatadine ( n = 183). Rupatadine ( P = 0.008) but not cetirizine ( P = 0.07) statistically reduced the baseline i6TSS vs placebo (47.8%, 44.7% and 38.8%, respectively), after 12 weeks. Onset of action was observed at the first 24 h for both treatments (rupatadine vs placebo, P = 0.013; cetirizine vs placebo, P = 0.015). Furthermore, instantaneous total nasal symptoms score (iTNSS) (including nasal blockage) mean change from baseline showed a significant reduction with rupatadine 10 mg in comparison with placebo, along all treatment duration of 12 weeks. Study treatments were well tolerated.
Conclusion: Rupatadine significantly relieves symptoms of PER, providing a rapid onset of action and maintains its effects over a long period of 12-weeks. 相似文献
46.
47.
Alicia Armentia Borja Bartolomé Miguel Puyo Carmen Paredes Silvia Calderón Teresa Asensio Valentín del Villar 《Annals of allergy, asthma & immunology》2007,98(4):329-336
BACKGROUND: Skin testing and sera measurements have verified the existence of tobacco specific IgE. However, the few published studies on this matter report conflicting results concerning their clinical significance. OBJECTIVE: To verify if a specific clinical allergenic response against tobacco might be possible in allergenic and nonallergenic bronchial diseases. METHODS: We performed a cross-sectional observational case-control analysis on 180 patients with asthma, chronic obstructive pulmonary disease (COPD), and bronchial carcinoma and controls who were randomly chosen. Skin prick tests and serum specific IgE to tobacco and related allergens, bronchial challenge with cigarettes and tobacco extract, patch tests with tobacco and nicotine, sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting, and Enzyme AllergoSorbent Test (EAST) inhibition were performed. RESULTS: Twenty-eight patients had positive tobacco skin prick test results. The association among positive skin prick test results, IgE, and bronchial challenge was strong (P < .001). Tobacco sensitivity was higher in patients with pollen asthma than in patients with COPD and carcinoma and negative in patients with intrinsic asthma and controls. A positive bronchial challenge result was related to the length of habit (P < .001) and the tobacco index in patients who had stopped smoking (P < .001). Delayed bronchial and patch response was more common in patients with COPD (P < .001). Tobacco IgE response (EAST) was related to sensitivity to Lolium perenne (rye grass) pollen (P < .001) but not to other vegetables that belong to the Solanaceae family. EAST inhibition showed cross-reactivity between tobacco and Lolium pollen. CONCLUSIONS: Tobacco may be responsible for a specific IgE response. Patients with pollen asthma were those with more positive responses to tobacco due to cross-reactivity between Lolium and tobacco allergens. 相似文献
48.
49.
50.
Antiviral and antioxidant activity of flavonoids and proanthocyanidins from Crataegus sinaica 总被引:4,自引:0,他引:4
Shahat AA Cos P De Bruyne T Apers S Hammouda FM Ismail SI Azzam S Claeys M Goovaerts E Pieters L Vanden Berghe D Vlietinck AJ 《Planta medica》2002,68(6):539-541
The antiviral and antioxidant activity of some fractions and of a series of flavonoids and proanthocyanidins obtained from Crataegus sinaica (Rosaceae) was evaluated. The O-glycosidic flavonoids and the oligomeric proanthocyanidins exhibited significant inhibitory activity against herpes simplex virus type 1 (HSV-1), which was shown to be due to an extracellular mechanism for procyanidin C-1. Procyanidin C-1 also had the highest antioxidant activity in both the microsomal lipid peroxidation and the hydroxyl radical scavenging assay. In addition to the previously reported phenolic compounds, the pentacyclic triterpenoid ursolic acid (1) and a tetrameric (2) and pentameric procyanidin (3) are reported for the first time. 相似文献