全文获取类型
收费全文 | 283篇 |
免费 | 9篇 |
专业分类
儿科学 | 10篇 |
妇产科学 | 13篇 |
基础医学 | 31篇 |
口腔科学 | 4篇 |
临床医学 | 16篇 |
内科学 | 56篇 |
皮肤病学 | 10篇 |
神经病学 | 11篇 |
外科学 | 24篇 |
综合类 | 23篇 |
预防医学 | 13篇 |
眼科学 | 53篇 |
药学 | 19篇 |
中国医学 | 1篇 |
肿瘤学 | 8篇 |
出版年
2023年 | 3篇 |
2022年 | 17篇 |
2021年 | 18篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 16篇 |
2015年 | 11篇 |
2014年 | 17篇 |
2013年 | 16篇 |
2012年 | 28篇 |
2011年 | 20篇 |
2010年 | 20篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 14篇 |
2006年 | 3篇 |
2005年 | 13篇 |
2004年 | 11篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1994年 | 1篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1956年 | 1篇 |
1954年 | 1篇 |
1942年 | 1篇 |
1940年 | 2篇 |
1939年 | 2篇 |
1937年 | 1篇 |
排序方式: 共有292条查询结果,搜索用时 15 毫秒
21.
Freya Tyrer Catherine W. McGrother Catherine F. Thorp Nicholas A. Taub Sabyasachi Bhaumik Domenic V. Cicchetti 《Journal of Applied Research in Intellectual Disabilities》2008,21(3):268-276
Background It is often useful to ascertain whether adults have moderate to profound intellectual disability (approximate IQ < 50; developmental age <108 months) when deciding whether to refer to specialist or mainstream services. The aim of the present study was to develop a simple measure to estimate moderate to profound intellectual disability in adults with a potential need for specialist care. Materials and Methods Three hundred and twenty‐two individuals with information on home interviews from the Leicestershire Learning Disability Register were also assessed using the Vineland Adaptive Behaviour Scales. A variety of variables concerning intelligence, adaptive functioning and dependency were used to predict developmental age (as estimated from the Vineland) using backward stepwise regression. The derived equation formed the Leicestershire Intellectual Disability (LID) tool. A cut‐off point was chosen using a receiver operator characteristic (ROC) curve to achieve 95% sensitivity in identifying moderate to profound intellectual disability. Results Seven variables from the home interviews were found to predict estimated developmental age at the 10% level (P ≤ 0.1). When the tool was used to detect adults with moderate to profound intellectual disability, the area under the ROC curve was 0.93. The chosen cut‐off point was 95% sensitive and 65% specific. The positive predictive value was 95%, the negative predictive value was 65%, and the overall diagnostic accuracy was 91%. Conclusions These preliminary findings suggest that the LID tool may help to identify adults with moderate to profound intellectual disability among those with potential need for specialist care. Further evaluation is recommended. 相似文献
22.
Lu J Murakami M Verma SC Cai Q Haldar S Kaul R Wasik MA Middeldorp J Robertson ES 《Virology》2011,410(1):64-75
Resistance to apoptosis is an important component of the overall mechanism which drives the tumorigenic process. EBV is a ubiquitous human gamma-herpesvirus which preferentially establishes latent infection in viral infected B-lymphocytes. EBNA1 is typically expressed in most forms of EBV-positive malignancies and is important for replication of the latent episome in concert with replication of the host cells. Here, we investigate the effects of EBNA1 on survivin up-regulation in EBV-infected human B-lymphoma cells. We present evidence which demonstrates that EBNA1 forms a complex with Sp1 or Sp1-like proteins bound to their cis-element at the survivin promoter. This enhances the activity of the complex and up-regulates survivin. Knockdown of survivin and EBNA1 showed enhanced apoptosis in infected cells and thus supports a role for EBNA1 in suppressing apoptosis in EBV-infected cells. Here, we suggest that EBV encoded EBNA1 can contribute to the oncogenic process by up-regulating the apoptosis suppressor protein, survivin in EBV-associated B-lymphoma cells. 相似文献
23.
24.
In this study, xanthan gum-facilitated ethyl cellulose microsponges were prepared by the double emulsification technique and subsequently dispersed in a carbopol gel base for controlled delivery of diclofenac sodium to the skin. Scanning electron microscopy revealed the porous, spherical nature of the microsponges. Increase in the drug/polymer ratio (0.4:1, 0.6:1, 0.8:1, m/m) increased their yield (79.1-88.5%), drug entrapment efficiency (50.0-64.1%), and mean particle diameter (181-255 μm). Compared to the microsponges with high drug/polymer ratio (0.8:1, m/m), the flux of entrapped drug through excised rat skin decreased by 19.9% and 17.0%, respectively, for the microsponges prepared at low and intermediate drug/polymer ratios. When an equivalent amount of pure drug (not entrapped into microsponges) was dispersed into the gel base and the flux was compared, the microsponges (drug/polymer ratio 0.8:1, m/m) were found to reduce the flux by 33.3%. Whether the drug was dispersed either in un-entrapped or entrapped form into the gel base, the drug permeation through rat skin followed Higuchi's diffusion kinetic model. The microsponges prepared at the lowest drug/polymer ratio exhibited a comparatively slower drug permeation profile and were hence considered most suitable for controlled drug delivery application. FTIR spectroscopy and DSC analyses indicated the chemically stable, amorphous nature of the drug in these microsponges. The gel containing these optimized microsponges was comparable to that of a commercial gel formulation and did not show serious dermal reactions. Hence, the microsponge system obtained at the lowest drug/polymer ratio could be useful for controlled release of diclofenac sodium to the skin. 相似文献
25.
Sabyasachi Biswas Sashwati Roy Jaideep Banerjee Syed-Rehan A. Hussain Savita Khanna Guruguhan Meenakshisundaram Periannan Kuppusamy Avner Friedman Chandan K. Sen 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(15):6976-6981
Ischemia complicates wound closure. Here, we are unique in presenting a murine ischemic wound model that is based on bipedicle flap approach. Using this model of ischemic wounds we have sought to elucidate how microRNAs may be implicated in limiting wound re-epithelialization under hypoxia, a major component of ischemia. Ischemia, evaluated by laser Doppler as well as hyperspectral imaging, limited blood flow and lowered tissue oxygen saturation. EPR oximetry demonstrated that the ischemic wound tissue had pO2 <10 mm Hg. Ischemic wounds suffered from compromised macrophage recruitment and delayed wound epithelialization. Specifically, epithelial proliferation, as determined by Ki67 staining, was compromised. In vivo imaging showed massive hypoxia inducible factor-1α (HIF-1α) stabilization in ischemic wounds, where HIF-1α induced miR-210 expression that, in turn, silenced its target E2F3, which was markedly down-regulated in the wound-edge tissue of ischemic wounds. E2F3 was recognized as a key facilitator of cell proliferation. In keratinocytes, knock-down of E2F3 limited cell proliferation. Forced stabilization of HIF-1α using Ad-VP16- HIF-1α under normoxic conditions up-regulated miR-210 expression, down-regulated E2F3, and limited cell proliferation. Studies using cellular delivery of miR-210 antagomir and mimic demonstrated a key role of miR-210 in limiting keratinocyte proliferation. In summary, these results are unique in presenting evidence demonstrating that the hypoxia component of ischemia may limit wound re-epithelialization by stabilizing HIF-1α, which induces miR-210 expression, resulting in the down-regulation of the cell-cycle regulatory protein E2F3. 相似文献
26.
Intelligent optimal control with dynamic neural networks. 总被引:2,自引:0,他引:2
The application of neural networks technology to dynamic system control has been constrained by the non-dynamic nature of popular network architectures. Many of difficulties are-large network sizes (i.e. curse of dimensionality), long training times, etc. These problems can be overcome with dynamic neural networks (DNN).In this study, intelligent optimal control problem is considered as a nonlinear optimization with dynamic equality constraints, and DNN as a control trajectory priming system. The resulting algorithm operates as an auto-trainer for DNN (a self-learning structure) and generates optimal feed-forward control trajectories in a significantly smaller number of iterations. In this way, optimal control trajectories are encapsulated and generalized by DNN. The time varying optimal feedback gains are also generated along the trajectory as byproducts. Speeding up trajectory calculations opens up avenues for real-time intelligent optimal control with virtual global feedback.We used direct-descent-curvature algorithm with some modifications (we called modified-descend-controller-MDC algorithm) for the optimal control computations. The algorithm has generated numerically very robust solutions with respect to conjugate points. The adjoint theory has been used in the training of DNN which is considered as a quasi-linear dynamic system. The updating of weights (identification of parameters) are based on Broyden-Fletcher-Goldfarb-Shanno BFGS method. Simulation results are given for an intelligent optimal control system controlling a difficult nonlinear second-order system using fully connected three-neuron DNN. 相似文献
27.
Odanacatib Restores Trabecular Bone of Skeletally Mature Female Rabbits With Osteopenia but Induces Brittleness of Cortical Bone: A Comparative Study of the Investigational Drug With PTH,Estrogen, and Alendronate 下载免费PDF全文
Abhishek Kumar Singh Pragya Shrivastava Mahesh Chandra Tiwari Geet Kumar Nagar Himangshu Kousik Bora Venkitanarayanan Parameswaran Sabyasachi Sanyal Jayesh R Bellare Naibedya Chattopadhyay 《Journal of bone and mineral research》2016,31(3):615-629
Cathepsin K (CK), a lysosomal cysteine protease, is highly expressed in mature osteoclasts and degrades type 1 collagen. Odanacatib (ODN) is a selective and reversible CK inhibitor that inhibits bone loss in preclinical and clinical studies. Although an antiresorptive, ODN does not suppress bone formation, which led us to hypothesize that ODN may display restorative effect on the osteopenic bones. In a curative study, skeletally mature New Zealand rabbits were ovarectomized (OVX) and after induction of bone loss were given a steady‐state exposure of ODN (9 mM/d) for 14 weeks. Sham‐operated and OVX rabbits treated with alendronate (ALD), 17b‐estradiol (E2), or parathyroid hormone (PTH) served as various controls. Efficacy was evaluated by assessing bone mineral density (BMD), bone microarchitecture (using micro‐computed tomography), fluorescent labeling of bone, and biomechanical strength. Skeletal Ca/P ratio was measured by scanning electron microscopy (SEM) with X‐ray microanalysis, crystallinity by X‐ray diffraction, and bone mineral density distribution (tissue mineralization) by backscattered SEM. Between the sham and ODN‐treated osteopenic groups, lumbar and femur metaphyseal BMD, Ca/P ratio, trabecular microstructure and geometric indices, vertebral compressive strength, trabecular lining cells, cortical parameters (femoral area and thickness and periosteal deposition), and serum P1NP were largely comparable. Skeletal improvements in ALD‐treated or E2‐treated groups fell significantly short of the sham/ODN/PTH group. However, the ODN group displayed reduced ductility and enhanced brittleness of central femur, which might have been contributed by higher crytallinity and tissue mineralization. Rabbit bone marrow stromal cells expressed CK and when treated with ODN displayed increased formation of mineralized nodules and decreased apoptosis in serum‐deficient medium compared with control. In vivo, ODN did not suppress remodeling but inhibited osteoclast activity more than ALD. Taken together, we show that ODN reverses BMD, skeletal architecture, and compressive strength in osteopenic rabbits; however, it increases crystallinity and tissue mineralization, thus leading to increased cortical bone brittleness. © 2015 American Society for Bone and Mineral Research. 相似文献
28.
Changes in Upper Airway Volume in Edentulous Obstructive Sleep Apnea Patients Treated with Modified Mandibular Advancement Device 下载免费PDF全文
29.
30.
Two amide–imine conjugates, viz. 3-methyl-benzoic acid (4-diethylamino-2-hydroxy-benzylidene)-hydrazide (L1) and 3-methyl-benzoic acid (2-hydroxy-naphthalen-1-ylmethylene)-hydrazide (L2), have been prepared and used for a further synthesis of Mo(vi) complexes (M1 and M2, respectively). Single crystal X-ray diffraction analysis confirmed their structures. Interestingly, M1 selectively recognizes Y3+ and Pb2+ at two different wavelengths, whereas M2 selectively interacts with Y3+ with a significantly high binding constant, 1.3 × 105 M−1. The proposed sensing mechanism involves the displacement of Mo(vi) by Y3+/Pb2+ from respective Mo(vi) complexes. The TCSPC experiment also substantiates the “turn-on” fluorescence process. A logic gate has been constructed utilizing the fluorescence recognition of cations by M1. DFT studies corroborated the cation–probe interactions and allowed exploring the orbital energy parameters.Two amide–imine conjugates and their Mo(vi) complexes (M1 and M2) were characterized by single crystal X-ray diffraction analysis. While M1 recognises both Y3+ and Pb2+ at two different wavelengths, M2 recognises only Y3+ with significantly high binding constant. 相似文献