全文获取类型
收费全文 | 715篇 |
免费 | 39篇 |
国内免费 | 34篇 |
专业分类
儿科学 | 43篇 |
妇产科学 | 9篇 |
基础医学 | 71篇 |
口腔科学 | 41篇 |
临床医学 | 111篇 |
内科学 | 156篇 |
皮肤病学 | 17篇 |
神经病学 | 14篇 |
特种医学 | 119篇 |
外科学 | 51篇 |
综合类 | 20篇 |
预防医学 | 31篇 |
眼科学 | 4篇 |
药学 | 80篇 |
肿瘤学 | 21篇 |
出版年
2023年 | 8篇 |
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 14篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 11篇 |
2014年 | 25篇 |
2013年 | 31篇 |
2012年 | 20篇 |
2011年 | 15篇 |
2010年 | 29篇 |
2009年 | 40篇 |
2008年 | 15篇 |
2007年 | 35篇 |
2006年 | 19篇 |
2005年 | 16篇 |
2004年 | 13篇 |
2003年 | 9篇 |
2002年 | 17篇 |
2001年 | 7篇 |
2000年 | 12篇 |
1999年 | 25篇 |
1998年 | 36篇 |
1997年 | 34篇 |
1996年 | 37篇 |
1995年 | 24篇 |
1994年 | 34篇 |
1993年 | 21篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 20篇 |
1988年 | 24篇 |
1987年 | 12篇 |
1986年 | 15篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1974年 | 2篇 |
排序方式: 共有788条查询结果,搜索用时 0 毫秒
51.
52.
Tryptic cleavage of proteinase-activated receptor-2 (PAR2) causes the unmasking of a tethered receptor-activating sequence, S37LIGRLDTP. We sought to determine, in the amino-terminal sequence of the PAR2 tethered ligand, the key amino acid residues that are responsible for receptor activation. Using site-directed mutagenesis, nine PAR2 mutants with alanine substitutions in the first six amino acids of the tethered ligand, S37LIGRL42., were prepared: PAR2S37A, PAR2L38A, PAR2I39A, PAR2G40A, PAR2R41A, PAR2A37-38, PAR2A39-42, PAR2A37,39-42, and PAR2A37-42, along with the reverse-sequence construct, PAR2L37S38. These mutants, together with wild-type PAR2(PAR2wt), were expressed in Kirsten virus-transformed rat kidney cells and were then assessed for receptor-mediated calcium signaling upon activation by trypsin and by receptor-activating peptides like SLIGRL-NH2. In addition, the release of the N-terminal receptor sequence that is cleaved from PAR2 by trypsin activation was monitored in the above cell lines using a site-targeted anti-receptor antibody. All PAR2 constructs were activated by SL-NH2, and all mutated tethered ligand sequences were unmasked by trypsin. However, differential activation of the receptor by trypsin in these mutants was observed: PAR2 mutants PAR2A37-38 and PAR2L37S38, in which the first two amino-terminal tethered ligand residues (S37L38) are either changed to alanines or reversed, yielded little or no response to trypsin, nor did PAR2A37,39-42. However, trypsin activated all other constructs. We conclude that the amino-terminal tethered ligand dipeptide sequence S37L38 plays a major role in the activation of PAR2. 相似文献
53.
54.
PR Hunziker S Smith M Scherrer-Crosbie N Liel-Cohen RA Levine R Nesbitt SA Benton MH Picard 《Circulation》1999,99(5):1-6
Background--Currently, the reporting and archiving of echocardiographic data suffer from the difficulty of representing heart motion on printable 2-dimensional (2D) media. Methods and Results--We studied the capability of holography to integrate motion into 2D echocardiographic prints. Images of normal human hearts and of a variety of mitral valve function abnormalities (mitral valve prolapse, systolic anterior motion of the mitral leaflets, and obstruction of the mitral valve by a myxoma) were acquired digitally on standard echocardiographic machines. Images were processed into a data format suitable for holographic printing. Angularly multiplexed holograms were then printed on a prototype holographic "laser" printer, with integration of time in vertical parallax, so that heart motion became visible when the hologram was tilted up and down. The resulting holograms displayed the anatomy with the same resolution as the original acquisition and allowed detailed study of valve motion with side-by-side comparison of normal and abnormal findings. Comparison of standard echocardiographic measurements in original echo frames and corresponding hologram views showed an excellent correlation of both methods (P<0.0001, r2=0.979, mean bias=2.76 mm). In this feasibility study, both 2D and 3D holographic images were produced. The equipment needed to view these holograms consists of only a simple point-light source. Conclusions--Holographic representation of myocardial and valve motion from echocardiographic data is feasible and allows the printing on a 2D medium of the complete heart cycle. Combined with the recent development of online holographic printing, this novel technique has the potential to improve reporting, visualization, and archiving of echocardiographic imaging. 相似文献
55.
急性缺血性卒中影像学检查的建议——美国心脏协会的科学声明(中) 总被引:1,自引:0,他引:1
2.3核磁共振血管成像(MRA)
2.3.1背景和方法:在头部MRI检查中常结合MRA,用于急性卒中患者病情评估以指导治疗决策的制定^[19]。日前,有几种不同的MRA技术用于脑血管成像,包括二维时间飞跃(timeof-flight,TOF)序列、三维TOF序列、 相似文献
56.
Al-Ani MZ Davies SJ Sloan P Rushton VE Horner K Gray RJ 《The British journal of oral & maxillofacial surgery》2004,42(4):335-336
The aim of this study was to investigate whether arthrography itself altered the range of mandibular movements, in a group of patients with locking of the temporomandibular joint (TMJ). The clinical records of a series of 161 patients who were diagnosed with locking of the TMJ were retrospectively analysed. Mouth opening had improved in 57 out of 161 patients (35%). Twenty-three patients (14%) had improved by 5 mm or less. Nineteen patients (11%) had improved by more than 5 mm but less than 10 mm, whereas 15 patients (9%) had improved by more than 10 mm. Of the patients who experienced an improved mouth opening, only nine (15%) had improved from their pre-arthrography restricted maximum opening to beyond the lower limit of normal. This suggests that the injection of contrast medium had an effect on the range of vertical opening in patients with displacement of the disc without reduction. 相似文献
57.
目的:建立大鼠的骨质疏松性椎体骨折模型,探讨骨折愈合程度与X射线、骨结构和力学性能的相互关系,以期能为临床治疗提供科学的指导和理论依据。方法:实验于2005-07/2006-07在解放军兰州军区总医院骨研所完成。实验动物:选择雌性SPF级8个月龄SD大鼠54只。实验分组:采用随机数字法将大鼠分为2组:骨质疏松组和对照组,每组27只。实验干预:骨质疏松组经双背侧手术切除卵巢,对照组行伪手术。术后3个月,所有动物麻醉下,采用L5椎体手术开窗刮除术区内松质骨方法建立人工椎体骨折模型。实验评估:于术后1,2,4,6,8,12周观察两组大鼠腰椎影像学、骨组织切片组织学与受累椎体力学性能。结果:54只SD大鼠全部进入结果分析。①影像学观察:术后两组X射线片示L5椎体有一骨折缺损透光区。对照组在术后6周时原透光区与周围骨质无明显差别,而骨质疏松组原透光区仍清晰可见,于8周时无明显差别。②组织学观察:两组软骨细胞在骨愈合1周时出现,形成软骨岛,但骨质疏松组软骨细胞每高倍视野数量明显少于对照组,另外,软骨细胞改建成成熟骨细胞,骨小梁形成数量,胶原纤维排列与对照组比较有显著性差异。③力学性能:在骨质愈合6~12周,L5椎体的最大载荷、弹性模量、最大应力明显低于同期对照组,差异有显著性意义(P<0.05)。结论:骨质疏松性椎体骨折SD大鼠模型,符合动物模型标准,可用于研究新骨形成与正常骨质结构关系,观察骨质疏松性椎体骨折愈合机制,并证明骨质疏松性松质骨骨折修复过程中,骨折愈合质量降低。 相似文献
58.
Background
We examined the association of alcohol use disorders (AUD) with adherence to and health-related quality of life (HRQOL) outcomes of antiretroviral treatment (ART) for HIV/AIDS patients.Methods
A cross-sectional multi-site survey was conducted in 468 drug users and 648 non-drug users (age: 35.4 ± 7.0 years; 63.8% male) in 3 epicentres of Vietnam. AUD, ART adherence, and HRQOL were measured using the Alcohol Use Disorders Identification Test - Consumption (AUDIT-C), the self-reported Visual Analogue Scale (VAS), and the World Health Organization Quality of Life instrument (WHOQOL-HIV BREF).Results
35.0% of drug users were hazardous drinkers, compared to 25.9% of non-drug users. 22.3% of drug users engaged in binge drinking, and 25.9% reported suboptimal ART adherence. Adjusting for propensity scores of AUD, patients who had either at-risk or binge drinking behaviour were about twice as likely to be treatment non-adherent as those who did not have AUD. Hazardous drinkers reported small to medium decrements in the Performance, Physical, Social, Spirituality, and Environment quality of life domains. Binge drinkers had a slightly higher score in Social dimension.Conclusion
AUD is prevalent and negatively affecting adherence to and HRQOL outcomes of ART services in injection-driven HIV epidemics. Screening and intervention are recommended for AUD, especially during the stable periods of ART. Other social and psychological interventions might also enhance patients’ responses to and outcomes of ART in Vietnam. 相似文献59.
60.