全文获取类型
收费全文 | 2266篇 |
免费 | 125篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 69篇 |
儿科学 | 8篇 |
妇产科学 | 12篇 |
基础医学 | 336篇 |
口腔科学 | 155篇 |
临床医学 | 183篇 |
内科学 | 649篇 |
皮肤病学 | 66篇 |
神经病学 | 106篇 |
特种医学 | 57篇 |
外科学 | 337篇 |
综合类 | 6篇 |
预防医学 | 64篇 |
眼科学 | 69篇 |
药学 | 103篇 |
肿瘤学 | 175篇 |
出版年
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 19篇 |
2017年 | 22篇 |
2016年 | 29篇 |
2015年 | 30篇 |
2014年 | 31篇 |
2013年 | 45篇 |
2012年 | 104篇 |
2011年 | 94篇 |
2010年 | 60篇 |
2009年 | 60篇 |
2008年 | 87篇 |
2007年 | 109篇 |
2006年 | 100篇 |
2005年 | 118篇 |
2004年 | 145篇 |
2003年 | 105篇 |
2002年 | 87篇 |
2001年 | 90篇 |
2000年 | 85篇 |
1999年 | 78篇 |
1998年 | 31篇 |
1997年 | 25篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1992年 | 51篇 |
1991年 | 50篇 |
1990年 | 44篇 |
1989年 | 59篇 |
1988年 | 57篇 |
1987年 | 45篇 |
1986年 | 62篇 |
1985年 | 52篇 |
1984年 | 49篇 |
1983年 | 34篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1979年 | 26篇 |
1978年 | 11篇 |
1977年 | 15篇 |
1975年 | 9篇 |
1974年 | 14篇 |
1972年 | 20篇 |
1970年 | 18篇 |
1969年 | 20篇 |
1968年 | 17篇 |
1967年 | 12篇 |
1966年 | 9篇 |
排序方式: 共有2395条查询结果,搜索用时 250 毫秒
41.
Maria Cristina Vianna Braga Katsuhiro Konno Fernanda C V Portaro José Carlos de Freitas Tetsuo Yamane Baldomero M Olivera Daniel C Pimenta 《Toxicon》2005,45(1):113-122
Carnivorous mollusks belonging to the genus Conus paralyze their prey by injecting a rich mixture of biologically active peptides. Conus regius is a vermivorous member of this genus that inhabits Brazilian tropical waters. Inter-, intra-species and individual variations of cone snail venom have been previously reported. In order to investigate intra-specific differences in C. regius venom, its feeding behavior and the correlation between these two factors, animals were pooled according to gender, size and season of collection, and their venom composition was compared by high performance liquid chromatography (HPLC). Both the whole venom and one specific peak were monitored by HPLC. Chromatographic profiles revealed no significant differences in their peak areas, indicating that the venom composition, based solely in the presence or absence of the major peaks, is stable regardless of season, gender and size. Therefore, analysis of one given toxin, eluting in one of the major peaks, is representative among the population. Moreover, this work presents the identification of one novel conotoxin (rg11a), which amino acid sequence was deduced by mass spectrometry. 相似文献
42.
43.
44.
Tadao Nakazawa Tetsuo Kondo Eiichi Sato Utaroh Motosugi Dongfeng Niu Kunio Mochizuki Tomonori Kawasaki Tetsu Yamane Ryohei Katoh 《Journal of cutaneous pathology》2015,42(11):897-902
Porocarcinoma is a rare malignancy with glandular adnexal differentiation. A 38‐year‐old Japanese man noticed a subcutaneous mass in right inguinal region about 20 years prior to being examined. Radiological examinations demonstrated the mass, 11 × 10 cm in size, was in the subcutaneous fat tissue. Recently, the mass grew rapidly, and it was biopsied by an orthopedist based on clinical diagnosis of primary soft tissue tumor. Histopathological examination of the resected specimens also revealed that the tumor lacked involvement to the skin. Microscopically, the tumor was mainly composed of poroid cells with partially obvious squamous differentiation, accompanied by focal ductal structures immunoreactive for CEA and EMA. The tumor contained a low‐grade area consisting of poroid cells and high‐grade area with squamous differentiation. This histopathological heterogeneity suggested malignant transformation from poroma. The patient had the tumor in almost same size over the period of 20 years, which is the longest in the previous reports. This unique case of subcutaneous porocarcinoma is reported. 相似文献
45.
Brain G protein gamma subunits contain an all-trans-geranylgeranylcysteine methyl ester at their carboxyl termini. 总被引:14,自引:16,他引:14 下载免费PDF全文
H K Yamane C C Farnsworth H Y Xie W Howald B K Fung S Clarke M H Gelb J A Glomset 《Proceedings of the National Academy of Sciences of the United States of America》1990,87(15):5868-5872
We have shown previously that guanine nucleotide-binding protein (G protein) beta gamma complexes purified from bovine brain membranes are methyl esterified on a C-terminal cysteine residue of the gamma polypeptide. In the present study, 3H-methylated G beta gamma complexes cleaved to their constituent amino acids by exhaustive proteolysis were shown to contain radiolabeled material that coeluted with geranylgeranylcysteine methyl ester on reversed-phase HPLC and two TLC systems. Further treatment by performic acid oxidation yielded radiolabeled material that coeluted with L-cysteic acid methyl ester, verifying that the prenyl modification occurs on a C-terminal cysteine residue. Analysis by gas chromatography-coupled mass spectrometry of material released from purified G beta gamma by treatment with Raney nickel positively identified the covalently bound lipid as an all-trans-geranylgeranyl (C20) isoprenoid moiety. To delineate the distribution of this modification among gamma subunits, purified G beta gamma complexes were separated into 5-kDa (gamma 5) and 6-kDa (gamma 6) forms of the gamma polypeptide by reversed-phase HPLC. Gas chromatography-coupled mass spectrometry analyses of Raney nickel-treated purified gamma 5 and gamma 6 subunits showed that both polypeptides were modified by geranylgeranylation. These results demonstrate that at least two forms of brain gamma subunit are posttranslationally modified by geranylgeranylation and carboxyl methylation. These modifications may be important for targeting G beta gamma complexes to membranes. 相似文献
46.
Teiichi Yamane Taro Date Yasuko Kanzaki Keiichi Inada Seiichiro Matsuo Kenri Shibayama Satoru Miyanaga Hidekazu Miyazaki Ken-ichi Sugimoto Seibu Mochizuki 《Circulation journal》2007,71(5):753-760
BACKGROUND: The limited efficacy and complications of segmental ostial pulmonary vein isolation (PVI) for treating atrial fibrillation (AF) have been discussed so, in the present study the feasibility and efficiency of performing segmental pulmonary vein (PV) antrum isolation to treat AF were assessed. METHODS AND RESULTS: A total of 187 patients with drug-refractory AF (paroxysmal 120, persistent 67) underwent segmental PVI guided by circumferential 20-electrode catheters (Lasso). Radiofrequency (RF) current was delivered either at the ostium using a regular Lasso (15-20 mm in diameter, 70 patients: Group 1) or at the antrum using a larger Lasso (25-30 mm in diameter, 117 patients: Group 2). A significantly wider region had to be ablated, with a longer RF application time, to isolate all 4 PVs in Group 2 patients than in Group 1 patients. Although the rate of recurrence of AF after the initial session was equal in both groups, a significantly greater number of patients were free from AF after a mean of 1.4 procedures in Group 2 than in Group 1 (93% vs 76% for paroxysmal AF, 78% vs 48% for persistent AF). CONCLUSIONS: Segmental antral PVI using large-sized Lasso catheters was found to be more effective and safer than ostial PVI for the treatment of AF. 相似文献
47.
48.
Calcium deposition in photocrosslinked poly(Pro‐Hyp‐Gly) hydrogels encapsulated rat bone marrow stromal cells 下载免费PDF全文
Farah Nurlidar Keisuke Yamane Mime Kobayashi Kayo Terada Tsuyoshi Ando Masao Tanihara 《Journal of tissue engineering and regenerative medicine》2018,12(3):e1360-e1369
Reproducing the features of the extracellular matrix is important for fabricating three‐dimensional (3D) scaffolds for tissue regeneration. A collagen‐like polypeptide, poly(Pro‐Hyp‐Gly), is a promising material for 3D scaffolds because of its excellent physical properties, biocompatibility, and biodegradability. In this paper, we present a novel photocrosslinked poly(Pro‐Hyp‐Gly) hydrogel as a 3D scaffold for simultaneous rat bone marrow stromal cell (rBMSC) encapsulation. The hydrogels were fabricated using visible‐light photocrosslinking at various concentrations of methacrylated poly(Pro‐Hyp‐Gly) (20–50 mg/ml) and irradiation times (3 or 5 min). The results show that the rBMSCs encapsulated in the hydrogels survived 7 days of incubation. Calcium deposition on the encapsulated rBMSCs was assessed with scanning electron microscope observation, Alizarin Red S, and von Kossa staining. The most strongly stained area was observed in the hydrogel formed with 30 mg/ml of methacrylated poly(Pro‐Hyp‐Gly) with 5‐min irradiation. These findings demonstrate that poly(Pro‐Hyp‐Gly) hydrogels support rBMSC viability and differentiation, as well as demonstrating the feasibility of using poly(Pro‐Hyp‐Gly) hydrogels as a cytocompatible, biodegradable 3D scaffold for tissue regeneration. 相似文献
49.
50.