全文获取类型
收费全文 | 667篇 |
免费 | 42篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 27篇 |
妇产科学 | 17篇 |
基础医学 | 108篇 |
口腔科学 | 38篇 |
临床医学 | 87篇 |
内科学 | 125篇 |
皮肤病学 | 4篇 |
神经病学 | 26篇 |
特种医学 | 65篇 |
外科学 | 102篇 |
综合类 | 12篇 |
一般理论 | 1篇 |
预防医学 | 36篇 |
眼科学 | 4篇 |
药学 | 41篇 |
中国医学 | 2篇 |
肿瘤学 | 14篇 |
出版年
2019年 | 3篇 |
2018年 | 13篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 26篇 |
2012年 | 26篇 |
2011年 | 10篇 |
2010年 | 19篇 |
2009年 | 15篇 |
2008年 | 18篇 |
2007年 | 13篇 |
2006年 | 17篇 |
2005年 | 14篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 16篇 |
2001年 | 11篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 10篇 |
1997年 | 16篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 16篇 |
1992年 | 15篇 |
1991年 | 17篇 |
1990年 | 19篇 |
1989年 | 26篇 |
1988年 | 17篇 |
1987年 | 19篇 |
1986年 | 20篇 |
1985年 | 15篇 |
1984年 | 19篇 |
1983年 | 14篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 19篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 14篇 |
1975年 | 10篇 |
1974年 | 9篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1971年 | 8篇 |
1904年 | 2篇 |
排序方式: 共有712条查询结果,搜索用时 31 毫秒
61.
Sidi A. Bencherif Abiraman Srinivasan Jeffrey A. Sheehan Lynn M. Walker Chakicherla Gayathri Roberto Gil Jeffrey O. Hollinger Krzysztof Matyjaszewski Newell R. Washburn 《Acta biomaterialia》2009,5(6):1872-1883
A series of resorbable poly(ethylene glycol)-co-poly(glycolic acid) (PEG-co-PGA, 4KG5) macromonomers have been synthesized with the chemistries from three different photopolymerizable end-groups (acrylates, methacrylates and urethane methacrylates). The aim of the study is to examine the effects of the chemistry of the cross-linker group on the properties of photocross-linked hydrogels. 4KG5 hydrogels were prepared by photopolymerization with high vinyl group conversion as confirmed by 1H nuclear magnetic resonance spectrometry using a 1D diffusion-ordered spectrometry pulse sequence. Our study reveals that the nature of end-groups in a moderately amphiphilic polymer can adjust the distribution and size of the micellar configuration in water, leading to changes in the macroscopic structure of hydrogels. By varying the chemistry of the cross-linker group (diacrylates (DA), dimethacrylates (DM) and urethane dimethacrylates (UDM)), we determined that the hydrophobicity of a single core polymer consisting of poly(glycolic acid) could be fine-tuned, leading to significant variations in the mechanical, swelling and degradation properties of the gels. In addition, the effects of cross-linker chemistry on cytotoxicity and proliferation were examined. Cytotoxicity assays showed that the three types of hydrogels (4KG5 DA, DM and UDM) were biocompatible and the introduction of RGD ligand enhanced cell adhesion. However, differences in gel properties and stability differentially affected the spreading and proliferation of myoblast C2C12 cells. 相似文献
62.
Adolfo JO Scherr Joao Paulo SN Lima Emma C Sasse Carmen SP Lima André D Sasse 《BMC cancer》2011,11(1):115
Background
Many adjuvant trials have been undertaken in an attempt to reduce the risk of recurrence among patients who undergo surgical resection for locally advanced renal cancer. However, no clear benefit has been identified to date. This systematic review was conducted to examine the exact role of adjuvant therapy in renal cancer setting. 相似文献63.
In the present study we investigated the effects of phenolic compounds present in Hypericum perforatum against neuronal excitotoxicity and mitochondrial dysfunction. Quercetin, kaempferol and biapigenin significantly reduced neuronal death caused by 100 microM kainate plus 100 microM N-methyl-D-aspartate. The observed neuroprotection was correlated with prevention of delayed calcium deregulation and with the maintenance of mitochondrial transmembrane electric potential. The three compounds were able to reduce mitochondrial lipid peroxidation and loss of mitochondrial transmembrane electric potential caused by oxidative stress induced by ADP plus iron. Moreover, biapigenin was also able to significantly affect mitochondrial bioenergetics and decrease the capacity of mitochondria to accumulate calcium. Taken together, the results suggest that the neuroprotective action induced by quercetin and kaempferol are mainly mediated by antioxidant effects, whereas biapigenin mainly affects mitochondrial bioenergetics and calcium uptake. 相似文献
64.
Hollinger JO Hart CE Hirsch SN Lynch S Friedlaender GE 《The Journal of bone and joint surgery. American volume》2008,90(Z1):48-54
The abilities of bone to remodel, fractures to repair, and bone grafts to incorporate are all fundamental reflections of the bone remodeling cycle. This process is characterized by the recruitment and differentiation of osteoblastic and osteoclastic cell populations, whose cellular activities are coordinated and regulated by an elaborate system of growth factors and cytokines. One of the crucial biological factors responsible for reparative osseous activity is platelet-derived growth factor (PDGF). The potent stimulatory effects of PDGF as a chemoattractant and mitogen for mesenchymal cells (including osteogenic cells), along with its ability to promote angiogenesis, have been demonstrated in a variety of preclinical models predicting maxillofacial, spine and appendicular skeletal, and soft-tissue applications. The biological profile of PDGF, including its ability to recruit osteoprogenitor cells, makes it particularly suited to address the skeletal defects that are seen with comorbid conditions such as osteoporosis, diabetes, and the effects of smoking. The clinical success and safety that have been demonstrated with use of recombinant human PDGF (rhPDGF) in the repair of periodontal defects have led to U.S. Food and Drug Administration (FDA) approval of rhPDGF for this indication. Ongoing pilot and pivotal trials in the United States and internationally will continue to clarify the promising role of PDGF in the treatment of challenging skeletal disorders. 相似文献
65.
Mittnacht AJ Joashi U Nguyen K Chin C Srivastava S Hollinger I 《Paediatric anaesthesia》2007,17(7):693-696
We describe a fast track anesthesia technique that facilitates congenital heart surgery via right axillary thoracotomy in children. Continuous positive airway pressure on the dependent lung, before and during cardiopulmonary bypass, approximates the heart towards the chest wall incision, and significantly improves the surgeon's access to the heart. 相似文献
66.
67.
68.
B Doll C Sfeir S Winn J Huard J Hollinger 《Critical reviews in eukaryotic gene expression》2001,11(1-3):173-198
Recent advances in bone tissue engineering are established on the understanding of an engineered scaffold, the molecular milieu within the osteogenic site, and the cell(s) predisposed to an osteogenic lineage. Advances in the incorporation of a generative vehicle into a skeletal defect require temporal and spatial distribution of the scaffold, growth factor, and cell compatible with enhanced bone healing. Monitoring events culminating in osteogenesis has focused on phenotypic and intracellular indicators. Phenotypic and intracellular indicators include the presence of receptors and intracellular signals that enable cell proliferation and differentiation. Progress in the areas of scaffold design, growth factor utilization, bone cell lineage, and intracellular signaling are reviewed. 相似文献
69.
70.
D E Bach L P Burgess T Zislis N Quigley J O Hollinger 《Archives of otolaryngology--head & neck surgery》1991,117(4):390-395
Both autogenous bone grafts and demineralized freeze-dried allogeneic bone implants were evaluated for mandibular reconstruction. Four-centimeter segmental defects of the midbody of the edentulous mandible were reconstructed in 36 dogs, with specimens recovered at 3 and 6 months and quantitatively compared for total and new bone by histomorphometric analysis. Autogenous grafts consisted of corticocancellous cranial block (CB), corticocancellous iliac block (IB), and particulate cancellous iliac marrow (PM). The allogeneic bone was demineralized and freeze-dried, and consisted of particulate cortical endochondral bone (FP), cranial cortical block (FCB), and iliac cortical block (FIB). Clinically and histomorphometrically, results appeared to indicate that (1) CB compared favorably with IB at 3 and 6 months for total bone, but IB showed a trend for more new bone formation at 6 months, a trend that may be due to the thicker cortical component of CB, which requires longer time periods to remodel than the cancellous rich IB; (2) FP failed to achieve bony union at 3 months, with inadequate rates of new bone formation; and (3) FCB and FIB compared favorably for total bone with CB and IB at 6 months, although new bone for autogenous CB and IB was 26.9% and 45.4%, while new bone for allogeneic FCB and FIB represented only 7.9% and 17.4%. 相似文献