全文获取类型
收费全文 | 2611篇 |
免费 | 57篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 91篇 |
儿科学 | 37篇 |
妇产科学 | 19篇 |
基础医学 | 398篇 |
口腔科学 | 51篇 |
临床医学 | 165篇 |
内科学 | 521篇 |
皮肤病学 | 43篇 |
神经病学 | 215篇 |
特种医学 | 76篇 |
外科学 | 462篇 |
综合类 | 16篇 |
预防医学 | 48篇 |
眼科学 | 37篇 |
药学 | 237篇 |
中国医学 | 5篇 |
肿瘤学 | 253篇 |
出版年
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 37篇 |
2020年 | 20篇 |
2019年 | 19篇 |
2018年 | 29篇 |
2017年 | 23篇 |
2016年 | 29篇 |
2015年 | 28篇 |
2014年 | 54篇 |
2013年 | 96篇 |
2012年 | 149篇 |
2011年 | 167篇 |
2010年 | 83篇 |
2009年 | 97篇 |
2008年 | 134篇 |
2007年 | 178篇 |
2006年 | 173篇 |
2005年 | 190篇 |
2004年 | 185篇 |
2003年 | 211篇 |
2002年 | 198篇 |
2001年 | 50篇 |
2000年 | 42篇 |
1999年 | 35篇 |
1998年 | 54篇 |
1997年 | 42篇 |
1996年 | 35篇 |
1995年 | 34篇 |
1994年 | 29篇 |
1993年 | 17篇 |
1992年 | 20篇 |
1991年 | 20篇 |
1990年 | 18篇 |
1989年 | 29篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 6篇 |
1985年 | 17篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1974年 | 5篇 |
1967年 | 2篇 |
排序方式: 共有2674条查询结果,搜索用时 203 毫秒
31.
Effects of succinylated concanavalin A on infectivity and syncytial formation of human immunodeficiency virus 总被引:3,自引:0,他引:3
Toshio Matsui Susumu Kobayashi Osamu Yoshida Shin-ichi Ishii Yukichi Abe Naoki Yamamoto 《Medical microbiology and immunology》1990,179(5):225-235
The effects of various lectins on the infectivity of human immunodeficiency virus (HIV) type 1 was investigated. Among the 25 lectins investigated, 2 types of concanavalin A (Con A) and 3 types of phytohemagglutinin were found to inhibit HIV infection. Succinylated Con A (S-Con A) efficiently blocked HIV-induced formation of syncytia in a coculture of MOLT-4 cells and blocked cell-free infection by HIV of MT-4 cells. The HIV-binding study revealed that S-Con A only partially inhibited viral binding to cells, although the control Leu-3a monoclonal antibody strongly inhibited it. When S-Con A was added to cultures after the initiation of viral adsorption, the number of HIV antigen-positive cells that developed depended on the time interval before addition of the compound. S-Con A inhibited HIV infection even after viral binding to cells at 0 °C and further incubation at 37 °C for 1 day. These data suggest that S-Con A inhibited mainly the fusion process rather than viral binding to cells in exerting its anti-HIV activity. 相似文献
32.
Ken-ichi Sasaki Yasuo Kokai Shin-ichi Atsumi Hirotoshi Tobioka Norimasa Sawada Koichi Hirata Michio Mori 《Medical Electron Microscopy》1998,31(2):61-67
Epithelioid disorganization is a hallmark of gastrointestinal cancers and is believed to be associated with malignant phenotypes such as invasiveness and the potentiality for metastasis. Although tight junctions (TJs) are known to be crucial for the maintenance of polarized organization of the gastrointestinal epithelium, changes in the TJ proteins in human cancers have not yet been fully elucidated. In this report, we investigated the expression and localization of three TJ proteins-barmotin (7H6 antigen), occludin, and ZO-1-in three phenotypically different human colon cancer cell lines exhibiting differnt grades of epithelioid organization. All three proteins were localized at the most apical part of the cell border corresponding to the site of TJs in T84 cells, in which epithelioid organization was well preserved. In contrast, in COLO320DM cells, which showed no epithelioid phenotypes, occludin was not detectable at either the protein or mRNA level, although barmotin and ZO-1 were present in the cytoplasm. In the third cell line, DLD-1, which showed an epithelioid phenotype intermediate between T84 and COLO320DM, aberrant expression of occludin was found in the basolateral cell membrane. On the other hand, barmotin was present in the cytoplasm, whereas ZO-1 was localized at the cell border. These observations showed that changes in the expression of TJ proteins occur in close correlation with epithelioid disorganization in human colon cancers. 相似文献
33.
Isolation and genetic characterization of human KB cell lines resistant to multiple drugs 总被引:32,自引:0,他引:32
Shin-ichi Akiyama Antonio Fojo John A. Hanover Ira Pastan Michael M. Gottesman 《Somatic Cell and Molecular Genetics》1985,11(2):117-126
Human KB cell lines resistant to high levels of colchicine were isolated by several successive single-step selections. Most of these selection steps resulted in cross-resistance to vincristine, vinblastine, adriamycin, actinomycin D, and puromycin; however, at the highest levels of colchicine resistance, increased cross-resistance to other drugs was not observed. There was no major change in protein synthesis or alteration in protein phosphorylation or [14C]glucosamine labeling patterns accompanying the development of multiple drug resistance as measured by analysis of metabolically labeled proteins on SDS gels. Cell-cell hybridization experiments showed that the colchicine-resistant and multiple drug-resistant phenotypes were incompletely dominant. In addition, colchicine resistance was found to segregate independently from resistance to other drugs in one somatic cell hybrid, suggesting that complex genetic loci are involved in the development of the multiple drug-resistant phenotype. These mutants should be useful for the study of the clinically important problem of multiple drug resistance in human cancer. 相似文献
34.
Shin-ichi Terao Gen Sobue Yoshio Hashizume Noriko Shimada Terunori Mitsuma 《Acta neuropathologica》1994,88(2):137-142
A quantitative analysis was made of the myelinated fibers in the lateral corticospinal tract (LCST) at the levels of the 6th cervical, 7th thoracic and 4th lumbar spinal segments in 20 patients between 19 and 90 years old, and who died of non-neurological diseases. The diameter frequency histograms of myelinated fibers of LCST showed a bimodal pattern with a sharp peak of the small myelinated fibers and broad slope of the large myelinated fibers. The ratio of small fiber to large fiber densities was significantly higher in the 6th cervical (P<0.05) and 4th lumbar segments (P<0.01) than in the 7th thoracic segments. The density of small myelinated fibers was significantly lowered with advancing age (P<0.050.001), while that of large myelinated fibers was not significantly decreased in the aged patients, although it showed a slight age-dependent declining tendency. Age-dependent decline of small fiber density was more prominent in the cervical and lumbar segments. Retraction of the axon-collaterals from large-diameter myelinated fibers, which are abundant in the cervical and lumbar segments, may contribute to the age-related diminution of the small myelinated fibers in the LCST.Part of this work was supported by grants from the Ministry of Welfare and Health of Japan, and a grant from Uehara Memorial Research Foundation 相似文献
35.
Shin-ichi Niwa Masataka Ohta Kiyoyuki Yamazaki 《Journal of autism and developmental disorders》1983,13(1):33-42
Cognitive functioning in autistic subjects was investigated by employing ERP recordings. The sample included four autistic patients, with five normal subjects and four Down's syndrome patients serving as the two control groups. The P300 component was investigated under three different experimental conditions, that is; “No-task,” “Counting,” and “Key-press. ” Two out of four autistic subjects were able to perform the required task under the Counting condition. However, none of them were able to complete the task for the Key-press condition. Autistic subjects demonstrated a lower amplitude of the P300 component under the No-task condition as compared to the other two groups. It was speculated that the autistic, as opposed to the other two groups, had some cognitive difficulties in the “active stimulus evaluating process”. 相似文献
36.
Shin-ichi Hirano Naoki Agata Yutaka Hara Hiroshi Iguchi Masataka Shirai Hiroshi Tone Norimoto Urakawa 《Cancer chemotherapy and pharmacology》1991,28(4):266-272
Summary In the present study we examined the effects of pirarubicin [(2R)-4-0-tetrahydropyranyladriamycin, THP] on a cardiovascular system. An injection of THP (0.39–3.13 mg/kg, i. v.) reduced the mean blood pressure and caused an increase in the respiratory air rate in anesthetized rats. At 1.5×10–6–1.5×10–5
m, THP markedly relaxed a contraction induced by 10–7
m norepinephrine in rat aorta with endothelium but not in that without endothelium. At a dose of 0.02–0.5 mg, THP produced an increase in the contractile force and the perfusion flow of isolated perfused guinea pig hearts. At a higher concentration (4.5×10–5–1.5×10–4
m), it produced a slight increase in the contractile force of the left atria in guinea pigs. This positive inotropic action of THP was inhibited by diphenhydramine (10–6–5×10–5
m), chlorpheniramine (3×10–7–3×10–5
m), and tripelennamine (3×10–7–3×10–5
m) but not by propranolol (10–6
m), cimetidine (10–5
m), diltiazem (10–6
m), or ryanodine (10–8
m). THP given i. v. at 2.5 mg/kg elevated the plasma histamine level in anesthetized dogs. From these data, we conclude that THP mainly relaxed the rat aorta in the presence of endothelium and that at higher concentrations, it increased the contractile force in the cardiac muscle, probably mediated through the release of histamine. 相似文献
37.
Role of expression of focal adhesion kinase in progression of hepatocellular carcinoma. 总被引:9,自引:0,他引:9
Shinji Itoh Takashi Maeda Mitsuo Shimada Shin-ichi Aishima Ken Shirabe Shinji Tanaka Yoshihiko Maehara 《Clinical cancer research》2004,10(8):2812-2817
PURPOSE: Although hepatocellular carcinoma (HCC) is the most common cancer of the human liver, the mechanisms that regulate HCC development and progression remain unclear. The aim of this study was to investigate whether focal adhesion kinase (FAK) is involved in the progression of human HCC. EXPERIMENTAL DESIGN: Western blot analysis for FAK was performed on three HCC cell lines. We reviewed 64 consecutive patients who had undergone initial liver resection for HCC without preoperative treatment. Immunohistochemistry analysis for FAK was performed on paraffin-embedded tissues. FAK expression was confirmed by Western blot analysis in several clinical samples. We investigated the correlation between FAK expression and clinical outcome. RESULTS: FAK proteins were detected in all HCC cell lines. Hepatocytes in the normal liver and chronic hepatitis with or without cirrhosis were negative for immunohistochemical staining for FAK expression. Cytoplasmic FAK expression was observed in 18 of 64 patients (28.1%), and this positive staining was correlated with gender (P < 0.05), a lower level of serum albumin (P < 0.05), and portal venous invasion (P < 0.01). Positive staining for FAK was associated with significantly poorer survival (P < 0.05). In multivariate analysis, FAK overexpression was an independent factor in determining the prognosis of patients. CONCLUSIONS: These data suggest that FAK plays an important role in promoting tumor progression, especially vascular invasion, in HCC. FAK could play an important role in HCC progression and would be a novel target for HCC therapeutics as well as a prognostic marker. 相似文献
38.
Shin-ichi Fukumoto Naoko Yamauchi Hisashi Moriguchi Yoshitaka Hippo Akira Watanabe Junji Shibahara Hirokazu Taniguchi Shumpei Ishikawa Hirotaka Ito Shogo Yamamoto Hiroko Iwanari Mitsugu Hironaka Yuichi Ishikawa Toshiro Niki Yasunori Sohara Tatsuhiko Kodama Masaharu Nishimura Masashi Fukayama Hirotoshi Dosaka-Akita Hiroyuki Aburatani 《Clinical cancer research》2005,11(5):1776-1785
PURPOSE: Squamous cell carcinoma (SCC) and adenocarcinoma of the lung are currently subject to similar treatment regimens despite distinct differences in histology and epidemiology. The aim of this study is to identify a molecular target with diagnostic and therapeutic values for SCC. EXPERIMENTAL DESIGN: Genes specifically up-regulated in SCC were explored through microarray analysis of 5 SCCs, 5 adenocarcinomas, 10 small cell lung carcinomas, 27 normal tissues, and 40 cancer cell lines. Clinical usefulness of these genes was subsequently examined mainly by immunohistochemical analysis. RESULTS: Seven genes, including aldo-keto reductase family 1, member B10 (AKR1B10), were identified as SCC-specific genes. AKR1B10 was further examined by immunohistochemical analysis of 101 non-small cell lung carcinomas (NSCLC) and its overexpression was observed in 27 of 32 (84.4%) SCCs and 19 of 65 (29.2%) adenocarcinomas. Multiple regression analysis showed that smoking was an independent variable responsible for AKR1B10 overexpression in NSCLCs (P < 0.01) and adenocarcinomas (P < 0.01). AKR1B10 staining was occasionally observed even in squamous metaplasia, a precancerous lesion of SCC. CONCLUSION: AKR1B10 was overexpressed in most cases with SCC, which is closely associated with smoking, and many adenocarcinoma cases of smokers. These results suggest that AKR1B10 is a potential diagnostic marker specific to smokers' NSCLCs and might be involved in tobacco-related carcinogenesis. 相似文献
39.
Shin-ichi Araki 《Clinical and experimental nephrology》2014,18(2):230-233
Epidemiological studies suggest the existence of a genetic susceptibility to the development of diabetic nephropathy. The apolipoprotein E gene (APOE), which is well known to have a polymorphism (ε2, ε3, and ε4) in exon 4, has been considered a candidate gene susceptible to this complication, because this variation was reportedly involved in lipid metabolism. To date, numerous case–control studies in patients with type 1 and type 2 diabetes have been reported. Although the ε2 allele of the APOE polymorphism tends to be associated with an increased risk for diabetic nephropathy, the results of these case–control comparisons are conflicting. However, a family-based study (the transmission/disequilibrium test) provided strong evidence that the ε2 allele was preferentially transmitted to patients with diabetic nephropathy but not transmitted to those without it. Several prospective follow-up studies also reported an increased risk for progression to higher stages of diabetic nephropathy for the ε2 carriers. Furthermore, two recent meta-analyses reported that the ε2 allele is associated with a risk for diabetic nephropathy. Based on the results of these studies, the ε2 allele of the APOE polymorphism seems to be a genetic risk factor for diabetic nephropathy susceptibility. However, this genetic effect only accounts for a small proportion of this complication, and the mechanism remains unclear at present. Further studies are needed to explore whether genotyping of the APOE polymorphism in patients with diabetes is of value for better management in clinical practice. 相似文献
40.
Eiji Wada Mitsuru Fukui Kazuhisa Takahashi Daisaku Takeuchi Hiroshi Hashizume Masahiko Kanamori Noboru Hosono Tsukasa Kanchiku Yuichi Kasai Miho Sekiguchi Shin-ichi Konno Mamoru Kawakami Kazuo Yonenobu 《Journal of orthopaedic science》2019,24(1):57-61