全文获取类型
收费全文 | 768篇 |
免费 | 61篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 27篇 |
妇产科学 | 18篇 |
基础医学 | 54篇 |
口腔科学 | 12篇 |
临床医学 | 88篇 |
内科学 | 146篇 |
皮肤病学 | 22篇 |
神经病学 | 37篇 |
特种医学 | 137篇 |
外科学 | 130篇 |
综合类 | 22篇 |
预防医学 | 52篇 |
眼科学 | 9篇 |
药学 | 21篇 |
肿瘤学 | 52篇 |
出版年
2023年 | 6篇 |
2021年 | 18篇 |
2020年 | 11篇 |
2019年 | 8篇 |
2018年 | 18篇 |
2017年 | 16篇 |
2016年 | 12篇 |
2015年 | 18篇 |
2014年 | 32篇 |
2013年 | 45篇 |
2012年 | 12篇 |
2011年 | 18篇 |
2010年 | 35篇 |
2009年 | 21篇 |
2008年 | 30篇 |
2007年 | 23篇 |
2006年 | 21篇 |
2005年 | 18篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 24篇 |
2001年 | 26篇 |
2000年 | 17篇 |
1999年 | 22篇 |
1998年 | 28篇 |
1997年 | 36篇 |
1996年 | 34篇 |
1995年 | 23篇 |
1994年 | 22篇 |
1993年 | 15篇 |
1992年 | 16篇 |
1991年 | 5篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 11篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 13篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有835条查询结果,搜索用时 15 毫秒
91.
T Wilmink M W C Claridge A Fries O Will C S Hubbard D J Adam C R G Quick A W Bradbury 《European journal of vascular and endovascular surgery》2006,32(1):16-20
BACKGROUND: The UK Multicentre Aneurysm Screening Study (MASS) showed a 44% reduction in AAA-related mortality after 4 years and predicted an increased number of deaths prevented in the longer term. We aim to compare the 5 and 13 years benefit from aneurysm screening in the Huntingdon Aneurysm screening programme. METHODS: Incidence and mortality of ruptured AAA (RAAA) after 5 and 13 years of screening in a population based aneurysm screening program. RESULTS: Five years of screening resulted in a reduction in the incidence of RAAA of 49% (95% CI: 3-74%). Nine out of 11 ruptures in the invited group did not survive (mortality 82%; 95% CI: 48-98%) compared to 38 non-survivors from 51 ruptures in the control group (mortality 75%; 95% CI: 60-86%). Five years of screening resulted in an RAAA-related mortality reduction of 45% (95% CI: -15 to 74%). After 13 years of screening the incidence of RAAA was reduced by 73% (95% CI: 58-82%). Twenty-one out of 29 ruptures in the invited group did not survive (mortality 72%; 95% CI: 53-87%) compared to 64 non-survivors from 82 ruptures in the control group (mortality 78%; 95% CI: 68-86%). Thirteen years screening resulted in a reduction of mortality from RAAA of 75% (95% CI: 58-84%). The number needed to screen to prevent one death reduced from 1380 after 5 years to 505 after 13 years. The number of elective AAA operations needed to prevent one death reduced from 6 after 5 years to 4 after 13 years. CONCLUSION: AAA screening becomes increasingly beneficial as screening continues over the longer term. Benefits continue to increase after screening has ceased. 相似文献
92.
93.
NUR AIN ALIAS WAN AZANI MUSTAFA MOHD AMINUDIN JAMLOS AHMED ALKHAYYAT KHAIRUL SHAKIR AB RAHMAN RAMI Q. MALIK 《Oncology research》2021,29(5):365-376
Cervical cancer is a prevalent and deadly cancer that affects women all over the world. It affects about 0.5 million women anually and results in over 0.3 million fatalities. Diagnosis of this cancer was previously done manually, which could result in false positives or negatives. The researchers are still contemplating how to detect cervical cancer automatically and how to evaluate Pap smear images. Hence, this paper has reviewed several detection methods from the previous researches that has been done before. This paper reviews pre-processing, detection method framework for nucleus detection, and analysis performance of the method selected. There are four methods based on a reviewed technique from previous studies that have been running through the experimental procedure using Matlab, and the dataset used is established Herlev Dataset. The results show that the highest performance assessment metric values obtain from Method 1: Thresholding and Trace region boundaries in a binary image with the values of precision 1.0, sensitivity 98.77%, specificity 98.76%, accuracy 98.77% and PSNR 25.74% for a single type of cell. Meanwhile, the average values of precision were 0.99, sensitivity 90.71%, specificity 96.55%, accuracy 92.91% and PSNR 16.22%. The experimental results are then compared to the existing methods from previous studies. They show that the improvement method is able to detect the nucleus of the cell with higher performance assessment values. On the other hand, the majority of current approaches can be used with either a single or a large number of cervical cancer smear images. This study might persuade other researchers to recognize the value of some of the existing detection techniques and offer a strong approach for developing and implementing new solutions. 相似文献
94.
The clinical spectrum of postpartum thyroid disease 总被引:1,自引:0,他引:1
Lazarus JH; Hall R; Othman S; Parkes AB; Richards CJ; McCulloch B; Harris B 《QJM : monthly journal of the Association of Physicians》1996,89(6):429-435
The clinical and biochemical features of postpartum thyroid disease were
analysed in 152 antithyroid peroxidase antibody-positive (anti TPO+ve)
women and compared with 239 anti-TPO-ve age-matched control postpartum
women. All were assessed monthly for up to 12 months postpartum. Seventy
three anti-TPO+ve women developed post-partum thyroiditis (PPT): 19.2%
hyperthyroid alone, 49.3% hypothyroid alone, and 31.5% characterized by
hyper- followed by hypothyroidism. None of the antibody-negative women
developed any thyroid dysfunction. A significant increase in many of eleven
symptoms of hypothyroidism and some of eight symptoms of hyperthyroidism
compared to control women was observed in all anti-TPO+ve women,
independent of thyroid status. This was particularly seen in women who
later developed PPT when they were euthyroid, but was also observed in
euthyroid anti-TPO+ve women who showed no decline of thyroid function
during the postpartum period. Although PPT is usually transient, this
condition, and the euthyroid antibody-positive state, may be associated
with significant symptomatology, including an increased incidence of minor
to moderate depression. Early recognition of this syndrome by antenatal
screening of thyroid antibodies may contribute to improved management of
women during the postpartum period.
相似文献
95.
96.
M Johannsen S Christensen R Zachariae AB Jensen 《Breast cancer research and treatment》2015,152(3):645-658
97.
Eelco AB Over GC Wanda Wendel-Vos Matthijs van den Berg Heleen H Hamberg-van Reenen Luqman Tariq Rudolf T Hoogenveen Pieter HM van Baal 《Cost effectiveness and resource allocation : C/E》2012,10(1):1-7
Background
Counseling in combination with pedometer use has proven to be effective in increasing physical activity and improving health outcomes. We investigated the cost-effectiveness of this intervention targeted at one million insufficiently active adults who visit their general practitioner in the Netherlands.Methods
We used the RIVM chronic disease model to estimate the long-term effects of increased physical activity on the future health care costs and quality adjusted life years (QALY) gained, from a health care perspective.Results
The intervention resulted in almost 6000 people shifting to more favorable physical-activity levels, and in 5100 life years and 6100 QALYs gained, at an additional total cost of EUR 67.6 million. The incremental cost-effectiveness ratio (ICER) was EUR 13,200 per life year gained and EUR 11,100 per QALY gained. The intervention has a probability of 0.66 to be cost-effective if a QALY gained is valued at the Dutch informal threshold for cost-effectiveness of preventive intervention of EUR 20,000. A sensitivity analysis showed substantial uncertainty of ICER values.Conclusion
Counseling in combination with pedometer use aiming to increase physical activity may be a cost-effective intervention. However, the intervention only yields relatively small health benefits in the Netherlands. 相似文献98.
Peroxidase-H2O2-halide system: Cytotoxic effect on mammalian tumor cells 总被引:28,自引:0,他引:28
Myeloperoxidase, H2O2, and a halide constitute a potent antimicrobial system. A cytotoxic effect of this system on a line of mouse ascitic lymphoma cells (LSTRA) is demonstrated here using four different assay systems: 51Cr release, trypan blue exclusion, inhibition of glucose C-1 oxidation, and loss of oncogenicity for mice. Deletion of each component of the system, preheating the peroxidase, or addition of azide, cyanide, or catalase abolished the cytotoxicity. Myeloperoxidase was effective with either chloride or iodide as the halide, while lastoperoxidase was effective with iodide but not chloride. The iodinated thyroid hormones, triiodothyronine and thyroxine, could substitute for the halide, and H2O2 could be replaced by a peroxide- generating enzyme system such as glucose and glucose oxidase or by H2O2 producing bacteria such as pneumococci or streptococci. The possibility is raised that the peroxidases of inflammatory cells and certain biologic fluids may affect tumor initiation or growth in vivo. 相似文献
99.
KRZYSZTOF JONDERKO ADAM KOCA TOMASZ GOAB GERARD JONDERKO 《Journal of gastroenterology and hepatology》1989,4(6):505-511
The effect of increasing intravenous doses of synthetic salmon calcitonin (0.0044, 0.0088, 0.0175, and 0.0350 iu/kg per min) versus placebo on the fasted gall-bladder volume was assessed in seven normal subjects according to a double-blind study protocol. In addition, the action of calcitonin on meal-induced gall-bladder emptying was examined. Gall-bladder volumes were measured by means of real-time ultrasonography. Calcitonin evoked a dose-dependent relaxation of the fasted gall-bladder. A statistically significant increase of the fasted gall-bladder volume was observed with 0.0175 (23.4 +/- 5.5 cm3 placebo versus 33.9 +/- 7.7 cm3 calcitonin, P less than 0.001) and 0.0350 (21.4 +/- 4.6 cm3 placebo versus 36.1 +/- 8.4 cm3 calcitonin, P less than 0.01) iu/kg per min calcitonin, whereas a mean increase of the gall-bladder volume amounted to 32.1% and 46.5%, respectively. A significant delay of the gall-bladder emptying after calcitonin was reflected by a decrease of the ejection fraction: 23.2 +/- 8.3% calcitonin versus 57.8 +/- 6.9% placebo (P less than 0.02) at 20 min, and 40.5 +/- 8.8% calcitonin versus 67.2 +/- 3.8% placebo (P less than 0.02) at 30 min after the test meal. Calcitonin is concluded to have a potent relaxing effect on the human gall-bladder. 相似文献
100.
Priming of human neutrophils with N-formyl-methionyl-leucyl- phenylalanine by a calcium-independent, pertussis toxin-insensitive pathway 总被引:1,自引:0,他引:1
Resting neutrophils may be "primed" to augmented effector function, eg, superoxide (O2-) production in the respiratory burst, upon a second stimulation with a variety of soluble agonists including formylated methionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA). At priming concentrations of FMLP (5 x 10(-9) mol/L) that did not initiate O2- generation, two metabolic activities were noted: (1) approximately a threefold increase in the baseline intracellular calcium (Ca++i) level, that was not dependent on extracellular Ca++, and (2) a rapid rise in intracellular pH that was blocked by 5-(N,N- dimethyl) amiloride (DA), that had no effect on the Ca++i response to priming. Furthermore, there were no significant increases in inositol metabolites in cells primed and stimulated with FMLP compared with cells receiving the stimulating dose of FMLP alone and pretreatment with pertussis toxin (PT) (before the addition of the priming -5 x 10(- 9) mol/L dose of FMLP), whereas abolishing the response to FMLP during the second stage of stimulation, had (1) no effect on FMLP-primed cells subsequently stimulated with PMA, and (2) only partially ablated the rise in Ca++i initiated with FMLP. That FMLP priming involved distinctive processes to those of the well characterized FMLP-coupled Ca++-dependent activation cascade was shown by the full priming effect attained in a Ca++-free buffer, which did not sustain an O2- response to a second-stage FMLP stimulation, but sustained a primed response to PMA. These data demonstrate that FMLP primes human neutrophils by a Ca++-independent and PT-insensitive pathway, offering a functional model for studying heterogeneous FMLP receptor-coupled reactions. 相似文献