全文获取类型
收费全文 | 1689540篇 |
免费 | 148329篇 |
国内免费 | 31731篇 |
专业分类
耳鼻咽喉 | 19450篇 |
儿科学 | 47657篇 |
妇产科学 | 40583篇 |
基础医学 | 222298篇 |
口腔科学 | 42194篇 |
临床医学 | 171041篇 |
内科学 | 323045篇 |
皮肤病学 | 35823篇 |
神经病学 | 127378篇 |
特种医学 | 68849篇 |
外国民族医学 | 498篇 |
外科学 | 241051篇 |
综合类 | 100662篇 |
现状与发展 | 88篇 |
一般理论 | 442篇 |
预防医学 | 132104篇 |
眼科学 | 38375篇 |
药学 | 132951篇 |
426篇 | |
中国医学 | 26402篇 |
肿瘤学 | 98283篇 |
出版年
2021年 | 26307篇 |
2020年 | 19326篇 |
2019年 | 20448篇 |
2018年 | 25199篇 |
2017年 | 22058篇 |
2016年 | 23230篇 |
2015年 | 30736篇 |
2014年 | 40458篇 |
2013年 | 48339篇 |
2012年 | 63909篇 |
2011年 | 70063篇 |
2010年 | 45461篇 |
2009年 | 41042篇 |
2008年 | 57168篇 |
2007年 | 59343篇 |
2006年 | 59512篇 |
2005年 | 57230篇 |
2004年 | 48989篇 |
2003年 | 47668篇 |
2002年 | 43510篇 |
2001年 | 73893篇 |
2000年 | 75618篇 |
1999年 | 64433篇 |
1998年 | 21821篇 |
1997年 | 19974篇 |
1996年 | 19867篇 |
1995年 | 19846篇 |
1994年 | 18148篇 |
1993年 | 16032篇 |
1992年 | 49238篇 |
1991年 | 47660篇 |
1990年 | 45560篇 |
1989年 | 43172篇 |
1988年 | 39890篇 |
1987年 | 39052篇 |
1986年 | 36658篇 |
1985年 | 35212篇 |
1984年 | 26656篇 |
1983年 | 22303篇 |
1982年 | 13930篇 |
1981年 | 12552篇 |
1979年 | 23626篇 |
1978年 | 17080篇 |
1977年 | 14381篇 |
1976年 | 13165篇 |
1975年 | 13716篇 |
1974年 | 16101篇 |
1973年 | 15407篇 |
1972年 | 14202篇 |
1971年 | 13041篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Patrick W. Keeley Mikayla C. Lebo Jordan D. Vieler Jason J. Kim Ace J. St. John Benjamin E. Reese 《The Journal of neuroscience》2021,41(1):103
Amacrine cells of the retina are conspicuously variable in their morphologies, their population demographics, and their ensuing functions. Vesicular glutamate transporter 3 (VGluT3) amacrine cells are a recently characterized type of amacrine cell exhibiting local dendritic autonomy. The present analysis has examined three features of this VGluT3 population, including their density, local distribution, and dendritic spread, to discern the extent to which these are interrelated, using male and female mice. We first demonstrate that Bax-mediated cell death transforms the mosaic of VGluT3 cells from a random distribution into a regular mosaic. We subsequently examine the relationship between cell density and mosaic regularity across recombinant inbred strains of mice, finding that, although both traits vary across the strains, they exhibit minimal covariation. Other genetic determinants must therefore contribute independently to final cell number and to mosaic order. Using a conditional KO approach, we further demonstrate that Bax acts via the bipolar cell population, rather than cell-intrinsically, to control VGluT3 cell number. Finally, we consider the relationship between the dendritic arbors of single VGluT3 cells and the distribution of their homotypic neighbors. Dendritic field area was found to be independent of Voronoi domain area, while dendritic coverage of single cells was not conserved, simply increasing with the size of the dendritic field. Bax-KO retinas exhibited a threefold increase in dendritic coverage. Each cell, however, contributed less dendrites at each depth within the plexus, intermingling their processes with those of neighboring cells to approximate a constant volumetric density, yielding a uniformity in process coverage across the population.SIGNIFICANCE STATEMENT Different types of retinal neuron spread their processes across the surface of the retina to achieve a degree of dendritic coverage that is characteristic of each type. Many of these types achieve a constant coverage by varying their dendritic field area inversely with the local density of like-type neighbors. Here we report a population of retinal amacrine cells that do not develop dendritic arbors in relation to the spatial positioning of such homotypic neighbors; rather, this cell type modulates the extent of its dendritic branching when faced with a variable number of overlapping dendritic fields to approximate a uniformity in dendritic density across the retina. 相似文献
23.
24.
目的 基于网络药理学和分子对接技术探究黄芪-赤芍配伍对治疗慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)的作用机制。方法 利用TCMSP,Pharmmaper数据库,筛选黄芪-赤芍治疗COPD的活性成分和潜在靶点;结合Genecards数据库挖掘的COPD相关靶点,对黄芪-赤芍药对与COPD靶点进行PPI网络构建,交互处理得到黄芪-赤芍药对治疗COPD的关键靶点,并进行GO分析和KEGG通路富集分析;并采用分子对接技术将主要活性成分与TNF-α(肿瘤坏死因子),IL-6(白细胞介素6)等进行分子对接;最后利用A549炎症细胞与人脐静脉内皮细胞缺氧损伤模型进行体外细胞实验对结果加以验证。结果 黄芪-赤芍药对中44个有效成分作用于COPD,核心成分为:槲皮素、山奈酚、丁子香萜、芍药苷、(2R,3R)-4-methoxyl-distylin、二氢异黄酮;黄芪-赤芍药对通过IL6、PTGS2、TNF等113个靶蛋白,调控Ras、PI3KAkt、IL-17等多条信号通路治疗COPD,且分子对接结果显示槲皮素、山奈酚、丁子香萜、芍药苷与IL-6、PTGS2、TNF大分子蛋白有良好的结合性,体外细胞试验证实,槲皮素与山奈酚均能减少IL-8,MMP-9炎症因子的分泌,具有不同程度的抗炎效果;芍药苷有明显的扩血管、抗血栓之效。结论 黄芪-赤芍药对治疗COPD具有多成分、多靶点、多通路、整体调节的作用特点。初步揭示了黄芪-赤芍药对通过抑制炎症反应、调节上皮细胞生长增强保护屏障等预测出黄芪-赤芍药对治疗COPD的潜在作用机制,以期为其活性成分的药效物质基础提供理论研究和思路。 相似文献
25.
Depeng Meng Yichen Meng Bingyang Li Guigang Zeng Bin Zhang Chunlin Hou Haodong Lin Yueping Ouyang 《Journal of orthopaedic science》2021,26(3):409-414
BackgroundComminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures.MethodsFrom March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed.ResultsIn total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05).ConclusionsTreatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments. 相似文献
26.
Yuxiang Ma Wenfeng Fang Hongyun Zhao Sai Praneeth Bathena Amol Tendolkar Jennifer Sheng Li Zhang 《The oncologist》2021,26(4):e549-e566
Lessons Learned
- The overall safety profiles of ipilimumab 3 mg/kg and 10 mg/kg administered every 3 weeks, were consistent between Chinese patients with solid tumors in the current study and patients from previous U.S. ipilimumab monotherapy studies. No new safety signals were identified.
- The mean systemic exposures to ipilimumab (assessed by first dose area under the curve during the dosing interval and maximum serum concentration) were numerically lower in the Chinese patient population than in U.S. patients for both 3 mg/kg and 10 mg/kg doses; however, the range of serum concentrations in the Chinese and U.S. populations overlapped (3 mg/kg and 10 mg/kg), suggesting that ipilimumab pharmacokinetics was ethnically insensitive in this study.
27.
28.
29.
“三全育人”视角下思政教育机制实践与探索——“杏林成长导师”计划的构建 《医学教育管理》2021,7(6):656-660
“三全育人”是高校思政教育工作的关键一环,也是中医药高校推动思政教育的重要内容。以“三全育人”为视角对北京中医药大学思想政治教育举措“杏林成长导师”计划路径、内容深入分析,运用统计分析和文献研究方法,剖析该计划对中医学专业大学生的学业、思想和实践等多个层面的现实成效,从而为“三全育人”理念在中医药院校制度建构中的应用提供新的视角与方法。 相似文献
30.