全文获取类型
收费全文 | 16451篇 |
免费 | 1122篇 |
国内免费 | 129篇 |
专业分类
耳鼻咽喉 | 141篇 |
儿科学 | 476篇 |
妇产科学 | 463篇 |
基础医学 | 2533篇 |
口腔科学 | 281篇 |
临床医学 | 1337篇 |
内科学 | 3932篇 |
皮肤病学 | 380篇 |
神经病学 | 2276篇 |
特种医学 | 446篇 |
外科学 | 1499篇 |
综合类 | 33篇 |
一般理论 | 1篇 |
预防医学 | 1007篇 |
眼科学 | 178篇 |
药学 | 1143篇 |
中国医学 | 35篇 |
肿瘤学 | 1541篇 |
出版年
2024年 | 30篇 |
2023年 | 208篇 |
2022年 | 442篇 |
2021年 | 751篇 |
2020年 | 409篇 |
2019年 | 509篇 |
2018年 | 665篇 |
2017年 | 484篇 |
2016年 | 553篇 |
2015年 | 613篇 |
2014年 | 749篇 |
2013年 | 998篇 |
2012年 | 1402篇 |
2011年 | 1417篇 |
2010年 | 800篇 |
2009年 | 726篇 |
2008年 | 1185篇 |
2007年 | 1083篇 |
2006年 | 993篇 |
2005年 | 881篇 |
2004年 | 805篇 |
2003年 | 723篇 |
2002年 | 541篇 |
2001年 | 75篇 |
2000年 | 48篇 |
1999年 | 69篇 |
1998年 | 109篇 |
1997年 | 67篇 |
1996年 | 48篇 |
1995年 | 42篇 |
1994年 | 45篇 |
1993年 | 22篇 |
1992年 | 26篇 |
1991年 | 23篇 |
1990年 | 23篇 |
1989年 | 21篇 |
1988年 | 13篇 |
1987年 | 13篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1974年 | 5篇 |
1966年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
MEMRI and tumors: a method for the evaluation of the contribution of Mn(II) ions in the extracellular compartment
下载免费PDF全文
![点击此处可从《NMR in biomedicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Eliana Gianolio Francesca Arena Enza Di Gregorio Roberto Pagliarin Martina Delbianco Gabriella Baio Silvio Aime 《NMR in biomedicine》2015,28(9):1104-1110
The purpose of the work was to set‐up a simple method to evaluate the contribution of Mn2+ ions in the intra‐ and extracellular tumor compartments in a MEMRI experiment. This task has been tackled by “silencing” the relaxation enhancement arising from Mn2+ ions in the extracellular space. In vitro relaxometric measurements allowed assessment of the sequestering activity of DO2A (1,4,7,10‐tetraazacyclododecane‐1,7‐diacetic acid) towards Mn2+ ions, as the addition of Ca‐DO2A to a solution of MnCl2 causes a drop of relaxivity upon the formation of the highly stable and low‐relaxivity Mn‐DO2A. It has been proved that the sequestering ability of DO2A towards Mn2+ ions is also fully effective in the presence of serum albumin. Moreover, it has been shown that Mn‐DO2A does not enter cell membranes, nor does the presence of Ca‐DO2A in the extracellular space prompt migration of Mn ions from the intracellular compartment. On this basis the in vivo, instantaneous, drop in SE% (percent signal enhancement) in T1‐weighted images is taken as evidence of the sequestration of extracellular Mn2+ ions upon addition of Ca‐DO2A. By applying the method to B16F10 tumor bearing mice, T1 decrease is readily detected in the tumor region, whereas a negligible change in SE% is observed in kidneys, liver and muscle. The relaxometric MRI results have been validated by ICP‐MS measurements. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
5.
Marco Maruzzo Umberto Basso Eugenio Borsatti Laura Evangelista Filippo Alongi Orazio Caffo Francesca Maines Sara Galuppo Rocco De Vivo Fable Zustovich Dario Palleschi Andrea Zivi Teodoro Sava Mariella Sorarù Roberto Iacovelli Maurizio Nicodemo Susanne Baier Lucia Fratino Vittorina Zagonel 《Clinical genitourinary cancer》2019,17(1):e187-e194
Background
Radium 223 was introduced for metastatic castration-resistant prostate cancer based on the results of a randomized controlled trial showing risk reduction for death and skeletal events. Our aim was to evaluate the outcome of patients receiving radium 223 in a real-world setting.Patients and Methods
We conducted a multicenter retrospective analysis in the Triveneto region of Italy.Results
One hundred fifty-eight patients received radium 223 in our region. After a median follow-up of 9.5 months, 75 patients died. The median overall survival (OS) was 14.2 months, and the median progression-free survival (PFS) was 6.2 months. Seventy-one (45%) patients achieved progression as best response. Thirty-seven (23%) patients stopped the treatment early because of progression. Eastern Cooperative Oncology Group performance status was prognostic for OS (18.4 vs. 12.3 vs. 7.5 months; 0 vs. 1, P = .0062; 0 vs. 2, P = .0002), whereas previous prostatectomy or docetaxel exposure were not. A neutrophil to lymphocytes ratio ≥ 3 significantly impacted OS (18.1 vs. 9.7 months; P < .001) and slightly impacted PFS (6.6 vs. 5.6 months; P = .05). Patients with a baseline alkaline phosphatase (ALP) value ≥ 220 U/L had worse OS and PFS (24.1 vs. 10.5 months; 7.2 vs. 5.5 months; P < .001). Patients with changes in ALP value achieved better OS (P = .029) and PFS (P = .002). There was no difference according to the line of therapy (0 vs. ≥ 1; P = .490). The main grade 3/4 toxicities were anemia, asthenia, and thrombocytopenia.Conclusion
This large real-world report confirms comparable OS and PFS data when compared with the pivotal study, as well as the predictive role of ALP and neutrophil to lymphocytes ratio. The definition of the optimal position of radium 223 in the treatment of metastatic castration-resistant prostate cancer has still to be defined. 相似文献6.
Augmentation technique with semitendinosus and gracilis tendons in chronic partial lesions of the ACL: clinical and arthrometric analysis 总被引:1,自引:0,他引:1
Roberto Buda Alberto Ferruzzi Francesca Vannini Lisa Zambelli Francesco Di Caprio 《Knee surgery, sports traumatology, arthroscopy》2006,14(11):1101-1107
Most of the techniques described in the literature for the repair of chronic partial ACL tears, don’t spare the intact portion of the ligament. The aim of this study was to perform a prospective analysis of the results of augmentation surgery using gracilis and semitendinosus tendons to treat partial sub-acute lesions of the ACL. This technique involves an “over the top” femoral passage, which enables salvage and strengthening of the intact portion of the ACL. The study included 47 patients treated consecutively at our institute from 1993 to 1998, with a mean injury-surgery interval of 18 weeks (range 12–36). The patients were followed up by clinical and instrumental assessment criteria at 3 months, 1 and 5 years after surgery. Clinical assessment was performed using the IKDC form. Subjective and functional parameters were assessed by the Tegner activity scale. Instrumental evaluation was done using the KT-2000 instrument: the 30-pound passive test and the manual maximum displacement test were performed. We obtained good or excellent results in 95.7% of cases. No recurrences in ligamentous laxity were observed. We believe that the described technique has the advantage of being compatible with ACL anatomy, and enables very rapid functional recovery. 相似文献
7.
Matteo Tosato Valentina Zamboni Alessandro Ferrini Matteo Cesari 《Clinical Interventions in Aging》2007,2(3):401-412
Aging is commonly defined as the accumulation of diverse deleterious changes occurring in cells and tissues with advancing age that are responsible for the increased risk of disease and death. The major theories of aging are all specific of a particular cause of aging, providing useful and important insights for the understanding of age-related physiological changes. However, a global view of them is needed when debating of a process which is still obscure in some of its aspects. In this context, the search for a single cause of aging has recently been replaced by the view of aging as an extremely complex, multifactorial process. Therefore, the different theories of aging should not be considered as mutually exclusive, but complementary of others in the explanation of some or all the features of the normal aging process. To date, no convincing evidence showing the administration of existing “anti-aging” remedies can slow aging or increase longevity in humans is available. Nevertheless, several studies on animal models have shown that aging rates and life expectancy can be modified. The present review provides an overlook of the most commonly accepted theories of aging, providing current evidence of those interventions aimed at modifying the aging process. 相似文献
8.
Eugenia Cordelli Anna Maria Fresegna Alessia D'Alessio Patrizia Eleuteri Marcello Spanò Francesca Pacchierotti Paola Villani 《Toxicological sciences》2007,99(2):545-552
The increasing request of chemical safety assessment demands for the validation of alternative methods to reduce the resort to animal experimentation. Methods that evaluate reproductive toxicity are among those requiring the largest use of animals. Presently, no validated in vitro alternative exists for the assessment of reproductive toxicity. Mammalian sperm are sensitive targets of DNA-reactive chemicals, which form premutagenic adducts. Here, we propose a new method based on comet assay to detect DNA damage induced by potential germ cell mutagens in bull sperm available from assisted reproduction practices. In somatic cells, chemical-induced adducts can be revealed by comet assay that detects DNA breaks produced during adduct repair. Mature sperm, however, are devoid of repair enzymes, and adducts are processed only after fertilization. For this reason, comet assay is not sensitive to detect DNA lesions induced in sperm by most chemicals. To overcome such limitation, we developed a modified comet assay based on the addition of a protein extract from HeLa cells to agarose-embedded sperm on microscopic slides. To test the method, sperm were treated in vitro with methyl methanesulfonate (MMS) or melphalan (MLP) and comet assay was conducted both with and without protein supplementation. No effect of MMS or MLP was detected without protein supplementation; on the contrary, a clear-cut dose-dependent effect was measured after addition of the cell extract. These results represent a proof of concept of a novel in vitro mutagenicity test on sperm that could offer a promising approach to complement previously validated in vivo germ cell genotoxicity assays. 相似文献
9.
Francesco Landi Ettore Capoluongo Andrea Russo Graziano Onder Matteo Cesari Paola Lulli Angelo Minucci Marco Pahor Cecilia Zuppi Roberto Bernabei 《Growth hormone & IGF research》2007,17(1):58-66
CONTEXT: Increasing evidences from experimental and human studies suggest that the activity of the growth hormone (GH/insulin-like growth factor-I) axis may contribute to the age-related cognitive decline and poor cognition in late life. OBJECTIVE: The aim of the present study was to evaluate the relationship of total serum free IGF-I and its binding protein-3 with cognitive performance in older persons aged 80 years or older. DESIGN: Data are from baseline evaluation of the ilSIRENTE study (n=353). Cognitive performance was evaluated using five items enclosed in the Minimum Data Set for Home Care assessment form: short-term memory, procedural memory, cognitive skills in daily decision making, verbal expression, comprehension. Free insulin-like growth factor-I (free IGF-I) and IGF-binding protein-3 (IGFBP-3) in blood were measured. Analysis of covariance (ANCOVA) was used to examine the relationship between cognitive impairment and the serum free IGF-I and IGFBP-3 concentrations, after adjustment for potential confounding variables. RESULTS: After adjustment for potential confounders, which included age, gender, education, cerebrovascular disease, ischemic heart disease, congestive heart failure, hypertension, diabetes, depression, Parkinson diseases, thyroid diseases, smoking status, alcohol abuse, body mass index, and number of medications, individuals with verbal expression problems (n=20) and individuals with comprehension problems (n=24) had a significantly lower serum levels of readily dissociable IGF-I than participants without cognitive impairments. The serum IGFBP-3 presented the same behavior of free IGF-I. CONCLUSION: The present study suggests that among old-old subjects living in the community lower levels of total serum free IGF-I and IGFBP-3 are associated with impairment of cognitive performance. This finding suggests that the GH/IGF-I axis may play an important role in the age-related decline of cognitive performance. 相似文献
10.
Couples in remarriages with stepchildren are a significant portion of the marriage population and have unique educational needs regarding aspects of couple functioning within the context of stepfamily development. From a review of the literature, we examine current curricula focused on these couples. Information is offered on implementation issues regarding recruitment, delivery context, facilitator and participant characteristics, and evaluation. 相似文献