全文获取类型
收费全文 | 14339篇 |
免费 | 1344篇 |
国内免费 | 991篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 154篇 |
妇产科学 | 133篇 |
基础医学 | 1618篇 |
口腔科学 | 279篇 |
临床医学 | 1886篇 |
内科学 | 2204篇 |
皮肤病学 | 135篇 |
神经病学 | 696篇 |
特种医学 | 503篇 |
外国民族医学 | 11篇 |
外科学 | 1278篇 |
综合类 | 2581篇 |
现状与发展 | 3篇 |
一般理论 | 1篇 |
预防医学 | 1054篇 |
眼科学 | 475篇 |
药学 | 1503篇 |
16篇 | |
中国医学 | 828篇 |
肿瘤学 | 1199篇 |
出版年
2024年 | 49篇 |
2023年 | 246篇 |
2022年 | 538篇 |
2021年 | 775篇 |
2020年 | 571篇 |
2019年 | 487篇 |
2018年 | 481篇 |
2017年 | 457篇 |
2016年 | 397篇 |
2015年 | 605篇 |
2014年 | 741篇 |
2013年 | 668篇 |
2012年 | 1080篇 |
2011年 | 1203篇 |
2010年 | 850篇 |
2009年 | 707篇 |
2008年 | 736篇 |
2007年 | 824篇 |
2006年 | 749篇 |
2005年 | 723篇 |
2004年 | 478篇 |
2003年 | 418篇 |
2002年 | 380篇 |
2001年 | 313篇 |
2000年 | 320篇 |
1999年 | 311篇 |
1998年 | 257篇 |
1997年 | 207篇 |
1996年 | 160篇 |
1995年 | 130篇 |
1994年 | 106篇 |
1993年 | 70篇 |
1992年 | 95篇 |
1991年 | 75篇 |
1990年 | 70篇 |
1989年 | 59篇 |
1988年 | 46篇 |
1987年 | 55篇 |
1986年 | 40篇 |
1985年 | 25篇 |
1984年 | 16篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1969年 | 8篇 |
1968年 | 6篇 |
1944年 | 6篇 |
1937年 | 6篇 |
1932年 | 10篇 |
1930年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Elke Wezenberg Robert Jan Verkes Ge S F Ruigt Wouter Hulstijn Bernard G C Sabbe 《Neuropsychopharmacology》2007,32(6):1272-1283
Ampakines act as positive allosteric modulators of AMPA-type glutamate receptors and facilitate hippocampal long-term potentiation (LTP), a mechanism associated with memory storage and consolidation. The present study investigated the acute effects of farampator, 1-(benzofurazan-5-ylcarbonyl) piperidine, on memory and information processes in healthy elderly volunteers. A double-blind, placebo-controlled, randomized, cross-over study was performed in 16 healthy, elderly volunteers (eight male, eight female; mean age 66.1, SD 4.5 years). All subjects received farampator (500 mg) and placebo. Testing took place 1 h after drug intake, which was around Tmax for farampator. Subjects performed tasks assessing episodic memory (wordlist learning and picture memory), working and short-term memory (N-back, symbol recall) and motor learning (maze task, pursuit rotor). Information processing was assessed with a tangled lines task, the symbol digit substitution test (SDST) and the continuous trail making test (CTMT). Farampator (500 mg) unequivocally improved short-term memory but appeared to impair episodic memory. Furthermore, it tended to decrease the number of switching errors in the CTMT. Drug-induced side effects (SEs) included headache, somnolence and nausea. Subjects with SEs had significantly higher plasma levels of farampator than subjects without SEs. Additional analyses revealed that in the farampator condition the group without SEs showed a significantly superior memory performance relative to the group with SEs. The positive results on short-term memory and the favorable trends in the trail making test (CTMT) are interesting in view of the development of ampakines in the treatment of Alzheimer's disease and schizophrenia. 相似文献
12.
13.
支气管动脉灌注化疗联合直线加速器放射治疗Ⅲa期非小细胞肺癌 总被引:1,自引:1,他引:0
目的 研究支气管动脉灌注化疗联合直线加速器放射治疗Ⅲa期非小细胞肺癌 (NSCLC)的可行性及临床价值。方法 76例NSCLC患者随机分成A、B 2组 ,A组先行 2次支气管动脉灌注化疗 (BAI) ,第 2次BAI 1~ 2周后再行直线加速器放射治疗 (RT) ;B组单纯行 2次BAI (对照组 )。结果 临床疗效 ,A组 (BAI RT)和B组 (BAI)分别为 89.47%和 60 .5 3% (Ρ <0 .0 1) ;1、3年生存率 ,A、B组分别为 81.5 8%、5 0 .0 0 %和 60 .5 3%、2 1.0 5 % ( 0 .0 1<Ρ <0 .0 5 )。结论 支气管动脉灌注化疗联合直线加速器放射治疗Ⅲa期非小细胞肺癌的临床疗效和患者 1、3年生存率均显著提高 相似文献
14.
15.
16.
作者根据现代免疫学观点,自1989年起采用自制中药“90增血剂”治疗ITP46例。期间,应用间接免疫荧光技术检测了患者外周血T淋巴细胞亚群,结果表明病例组全T细胞(CD_3)、T辅助/诱导细胞(CD_4)降低,T抑制/细胞毒细胞(CD_8)增高,CD_4/CD_8比值明显降低。治疗后,患者T亚群恢复常态,血小板数上升,骨髓产板型巨核细胞数增加,临床总有效率达91.2%,明显优于激素组(71.4%)。提示中药具有显著的疗效和良好的免疫调节作用。同时,动态观察ITP患者T细胞亚群的变化,对帮助临床判断治疗反应和预后有很大意义。 相似文献
17.
Preparation and characterization of porous beta-tricalcium phosphate/collagen composites with an integrated structure 总被引:11,自引:0,他引:11
Porous beta-tricalcium phosphate (TCP)/collagen composites with different beta-TCP/collagen weight ratio were prepared. The influences of the preparation conditions on the microstructure of porous composite and the joint status of beta-TCP particles with collagen fibrils were characterized by X-ray diffractometer, scanning electron microscopy and transmission electron microscopy. The results showed: (1) an acid treatment could effectively disassemble collagen fibrils; (2) in the resulting porous composites, beta-TCP particles homogenously existed on the skeleton of the collagen fibril network and bonded tightly to both the fibrils and themselves. The tight bonding formation could be due to the reaction between Ca ions in the particles and carboxyl groups in collagen polypeptide chains and due to the reprecipitation of partially dissolved beta-TCP during synthesis. The tight bonding between beta-TCP particles and collagen fibrils in the composites demonstrated an integrated structure, which was reproducible when beta-TCP/collagen ratio ranged from 2 to 4. Such integrated structure would make significant contributions in reliably tailoring properties of the porous composites by varying beta-TCP content. In addition, the porous composites had large porosity (approximately 95%) and appropriate pore size (approximately 100 microm), showed no negative impact in cytotoxicity assay and complete bone tissue regeneration after 12 weeks in animal test. 相似文献
18.
The role of a transmembrane protein, integrin alpha2beta1, to modulate the neural responses of cutaneous mechanoreceptors to mechanical indentation was examined using an isolated skin-nerve preparation in a rat model. Skin and its intact innervation were harvested from the medial thigh of the hindlimb and placed in a dish containing synthetic interstitial fluid. Using a standard teased nerve preparation, the neural responses of single slowly or rapidly adapting mechanoreceptors (SA or RA, respectively) were identified and the afferents categorized according to standard protocols (i.e. response to constant stimuli). The most sensitive spot of a mechanoreceptor's receptive field was identified and then stimulated using controlled compressive stress (constant or dynamic loads between threshold and saturation load for SAs and RAs, respectively). Loads were applied before, during, and after passive diffusion into the skin of a function-blocking anti-integrin alpha2 monoclonal antibody (FBmAb) or one of two types of control antibodies (immunoglobulin G or a FBmAb conjugated with a secondary antibody). The sensitivities of both SA and RA mechanoreceptors were profoundly reduced in the presence of the FBmAb, while not changing the waveforms of their action potentials or their adaptation properties. Both control antibodies had no significant effect on mechanoreceptors' sensitivities. Following removal of the FBmAb, the effects in some neurons were partially reversible. Taken together, the data from this study support the hypothesis that integrin alpha2beta1 plays a significant role in modulating mechanoreceptive response to compressive indentation. 相似文献
19.
Opioid kappa-agonists had much more potent inhibitory effects on the high K+-evoked Met-enkephalin release from rat brain slices than did the mu- or delta-agonists. The opioid kappa- antagonist, MR2266 enhanced the evoked release of Met-enkephalin to a greater extent than did mu- or delta-antagonists in vitro and had a potent analgesia in mice in vivo. These findings suggest that the release of Met-enkephalin may be regulated in vitro and in vivo, mainly by presynaptic kappa-receptor-mediated mechanisms. 相似文献
20.
Mengshu Zhang Likui Lu Bin Wei Yingying Zhang Xiang Li Yajun Shi Wei Ge Miao Sun 《American journal of medical genetics. Part A》2020,182(10):2432-2436
Brachydactyly type A (BDA) is defined as short middle phalanges of the affected digits and is subdivided into four types (BDA1‐4). To date, the molecular cause is unknown. However, there is some evidence that pathogenic variants of HOXD13 could be associated with BDA3 and BDA4. Here, we report a Chinese autosomal dominant BDA3 pedigree with a novel HOXD13 mutation. The affected individuals presented with an obviously shorter fifth middle phalanx. The radial side of the middle phalanx was shorter than the ulnar side, and the terminal phalanx of the fifth finger inclined radially and formed classical clinodactyly. Interestingly, the index finger was normal. The initial diagnosis was BDA3. However, the distal third and fourth middle phalanges were also slightly affected, resulting in mild radial clinodactyly. Both feet showed shortening of the middle phalanges, which were fused to the distal phalanges of the second to the fifth toes, as reported in BDA4. Therefore, this pedigree had combined BDA3 and atypical BDA4. By direct sequencing, a 13 bp deletion within exon 1 of HOXD13 (NM_000523.4: c.708_720del13; NP_000514.2: p.Gly237fs) was identified. The 13 bp deletion resulted in a frameshift and premature termination of HOXD13. This study provides further evidences that variants in HOXD13 cause BDA3‐BDA4 phenotypes. 相似文献