全文获取类型
收费全文 | 326篇 |
免费 | 5篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 7篇 |
妇产科学 | 3篇 |
基础医学 | 52篇 |
口腔科学 | 1篇 |
临床医学 | 38篇 |
内科学 | 43篇 |
皮肤病学 | 2篇 |
神经病学 | 2篇 |
特种医学 | 20篇 |
外科学 | 41篇 |
综合类 | 4篇 |
预防医学 | 22篇 |
眼科学 | 64篇 |
药学 | 16篇 |
中国医学 | 1篇 |
肿瘤学 | 10篇 |
出版年
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 12篇 |
2005年 | 3篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 12篇 |
1975年 | 5篇 |
1974年 | 13篇 |
1973年 | 6篇 |
1972年 | 12篇 |
1971年 | 11篇 |
1970年 | 11篇 |
1969年 | 9篇 |
1968年 | 9篇 |
1967年 | 8篇 |
1966年 | 9篇 |
1965年 | 6篇 |
排序方式: 共有331条查询结果,搜索用时 15 毫秒
1.
2.
Anu Juslin Jyrki L?tj?nen Sergey V Nesterov Kari Kalliokoski Juhani Knuuti Ulla Ruotsalainen 《Journal of nuclear cardiology》2007,14(1):82-91
BACKGROUND: The aim of this study was to develop a method to correct the heart position between two oxygen 15-labeled water cardiac positron emission tomography (PET) image sets to be able to use the equivalent regions of interest for the quantification of the perfusion values in the same myocardial segments. METHODS AND RESULTS: Independent component analysis was applied to the dynamic image sets (simulated phantom and 6 rest-pharmacologic stress and 10 rest-rest image sets of healthy female volunteers) acquired at different time points to separate the cardiac structures (ventricles and myocardium). The separated component images from independent component analysis from the 2 studies of the same individual were aligned with a normalized mutual information-based registration method. The alignment parameters were applied to position the regions of interest in the floating image sets for calculation of the myocardial blood flow values. In the rest case the mean myocardial blood flow value was 0.76 +/- 0.12 mL x g(-1) x min(-1) for the manual method and 0.79 +/- 0.10 mL x g(-1) x min(-1) for the proposed method (by use of the right ventricle component in the alignment), and in the stress case these values were 3.39 +/- 0.70 mL x g(-1) x min(-1) and 4.01 +/- 0.71 mL x g(-1) x min(-1), respectively. No statistically significant difference was found between the methods. CONCLUSION: In the tests with the phantom and patient images the alignment of cardiac structures was shown to be successful. The alignment could be done without the use of information from the myocardial compartment. 相似文献
3.
4.
5.
6.
7.
8.
Yulia A. Getmanenko Christopher S. Mullins Vladimir N. Nesterov Stephanie Lake Chad Risko Ezekiel Johnston-Halperin 《RSC advances》2018,8(63):36223
Here we present the synthesis and characterization of a hybrid vanadium-organic coordination polymer with robust magnetic order, a Curie temperature TC of ∼110 K, a coercive field of ∼5 Oe at 5 K, and a maximum mass magnetization of about half that of the benchmark ferrimagnetic vanadium(tetracyanoethylene)∼2 (V·(TCNE)∼2). This material was prepared using a new tetracyano-substituted quinoidal organic small molecule 7 based on a tricyclic heterocycle 4-hexyl-4H-pyrrolo[2,3-d:5,4-d′]bis(thiazole) (C6-PBTz). Single crystal X-ray diffraction of the 2,6-diiodo derivative of the parent C6-PBTz, showed a disordered hexyl chain and a nearly linear arrangement of the substituents in positions 2 and 6 of the tricyclic core. Density functional theory (DFT) calculations indicate that C6-PBTz-based ligand 7 is a strong acceptor with an electron affinity larger than that of TCNE and several other ligands previously used in molecular magnets. This effect is due in part to the electron-deficient thiazole rings and extended delocalization of the frontier molecular orbitals. The ligand detailed in this study, a representative example of fused heterocycle aromatic cores with extended π conjugation, introduces new opportunities for structure–magnetic-property correlation studies where the chemistry of the tricyclic heterocycles can modulate the electronic properties and the substituent at the central N-position can vary the spatial characteristics of the magnetic polymer.Here we present the synthesis and characterization of a hybrid vanadium-organic coordination polymer with robust magnetic order, a Curie temperature TC of ∼110 K, a coercive field of ∼5 Oe at 5 K. 相似文献
9.
One-Year Follow-up of Duodenal Ulcers after 1-Wk Triple Therapy for Helicobacter pylori 总被引:1,自引:0,他引:1
Joseph J. Y. Sung M.D. S.C. Sydney Chung M.D. Thomas K. VV. Ling Ph.D. Man Yee Yung R.N. Augustin F. B. Cheng M.D. Shorland W. Hosking M.D. Arthur K. C. Li M.D. 《The American journal of gastroenterology》1994,89(2):199-202
Objective : to study the ulcer recurrence rate of Helicobacter pylori-positive duodenal ulcers at 1 yr after eradication of the bacteria by triple therapy. Method : Patients with H. pylori-positive duodenal ulcers were randomized to receive either triple therapy for 1 wk plus omeprazole for 4 wk (THple+OMP) (n = 78), or omeprazole alone (OMP) for 4 wk (N = 77). Patients were followed up every 3 months for symptom enquiry. At 1 yr, all asymptomatic patients were invited to attend for gastroscopy. Results : At 8 wk, 16 patients in the OMP group and four in the Triple+OMP group had an ulcer. During the 1-yr period, 12 patients in the OMP group and no patient in the Triple+OMP group developed symptomatic ulcers. At follow-up endoscopy at 1 yr, another 10 ulcers were detected in the OMP group and two in the Triple+OMP group. Fifteen patients in the OMP group and 13 in the Triple+OMP group were lost to follow-up. In total, ulcers were de-tected in 39 of 61 (64%) assessahle patients in the OMP group, and in six of 65 (97o) assessahle patients in the Triple+OMP group after I yr (χ2 test: p < 0.001). Of the patients whose H, pytori were successfully eradicated hy Triple+OMP at 8 wk, 90% remained H. pylori negative at 1 yr. Conclusion : Triple therapy for 1 wk eradicates H, pylori infection and significantly reduces duodenal ulcer relapses. 相似文献
10.