全文获取类型
收费全文 | 2888篇 |
免费 | 142篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 63篇 |
妇产科学 | 30篇 |
基础医学 | 304篇 |
口腔科学 | 80篇 |
临床医学 | 241篇 |
内科学 | 833篇 |
皮肤病学 | 58篇 |
神经病学 | 198篇 |
特种医学 | 110篇 |
外科学 | 451篇 |
综合类 | 21篇 |
预防医学 | 60篇 |
眼科学 | 39篇 |
药学 | 207篇 |
中国医学 | 24篇 |
肿瘤学 | 322篇 |
出版年
2023年 | 18篇 |
2022年 | 25篇 |
2021年 | 49篇 |
2020年 | 40篇 |
2019年 | 27篇 |
2018年 | 45篇 |
2017年 | 32篇 |
2016年 | 40篇 |
2015年 | 47篇 |
2014年 | 74篇 |
2013年 | 89篇 |
2012年 | 110篇 |
2011年 | 121篇 |
2010年 | 71篇 |
2009年 | 54篇 |
2008年 | 107篇 |
2007年 | 127篇 |
2006年 | 110篇 |
2005年 | 136篇 |
2004年 | 114篇 |
2003年 | 142篇 |
2002年 | 149篇 |
2001年 | 132篇 |
2000年 | 103篇 |
1999年 | 104篇 |
1998年 | 42篇 |
1997年 | 41篇 |
1996年 | 32篇 |
1995年 | 27篇 |
1994年 | 15篇 |
1993年 | 17篇 |
1992年 | 75篇 |
1991年 | 59篇 |
1990年 | 73篇 |
1989年 | 76篇 |
1988年 | 60篇 |
1987年 | 49篇 |
1986年 | 36篇 |
1985年 | 54篇 |
1984年 | 38篇 |
1983年 | 30篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1979年 | 28篇 |
1978年 | 25篇 |
1977年 | 16篇 |
1974年 | 22篇 |
1973年 | 15篇 |
1970年 | 20篇 |
1967年 | 13篇 |
排序方式: 共有3057条查询结果,搜索用时 31 毫秒
11.
Reed Jon A.; Nador Roland G.; Spaulding David; Tani Yoichi; Cesarman Ethel; Knowles Daniel M. 《Blood》1998,91(10):3825-3832
12.
Perceptual dysfunction in hemiplegia and automobile driving. 总被引:1,自引:0,他引:1
Sixteen post-stroke, hemiplegic patients, who requested that they be allowed to return to driving, were extensively evaluated by a physiatrist, psychologist, occupational therapist, and driver training specialist. After they completed a driver training program, the patients were divided into three groups based on their driving program success and follow-ups. Significant differences in the psychological test results were found between Group I (those who drove without any difficulty) and Groups II and III (those who drove limited distance or who failed driver training). Results suggest that patients with significant cognitive and perceptual problems who take training and limit their driving can be safe drivers when they return to driving. 相似文献
13.
Flavobacterium meningosepticum IFO 12535, a menaquinone (MK) producer, was mutagenized to improve productivity. A mutant, which was resistant to 1-hydroxy-2-naphthoate (HNA), was found to produce MK more abundantly: 34 mg/liter of culture broth and 5.5 mg/g of dry cells. The mutant was less sensitive to inhibition by HNA on MK biosynthesis than the wild-type strain. MK was isolated from cells of the mutant and identified as MK-6 based on its physicochemical characteristics. Mutants, which were given each KCN resistance, aromatic amino acid auxotrophy and no carotenoid productivity, did not show further increase of productivity. 相似文献
14.
Masafumi Hara Yutaka Tsutsumi Keiichi Watanabe Sohtaro Suzuki Norio Tani Takeshi Miwa 《Pathology international》1985,35(4):831-840
Six solitary gastric polyps in the acid-secreting fundic mucosa were histo-chemically investigated using the mucin histochemistry, immunoperoxidase method, and silver methods for endocrine cells. Histologically, the polyps were grouped into three types : they largely consisted of either hyperplastic foveolar cells (group 1), normal-appearing fundic gland cells with mild cystic changes (group 2) or hyperplastic fundic gland cells with cystic dilatation (group 3). The presence of parietal cells and mucous neck cells was confirmed in all polyps by the immunoperoxidase method using parietal cell autoantibody and the paradoxical Concanavalin A staining, respectively. Regarding the endocrine component, somatostatin-containing cells, Grimelius-positive argyrophil cells, and Fontana-Masson-positive enterochromaffin cells were scattered in the fundic gland area of the polyps as well as in the surrounding normal-appearing fundic mucosa. Gastrin-containing cells were absent. In one of the group 2 polyps and both group 3 polyps, a varying number of glicentin-containing cells were found among the fundic gland components : In one polyp in group 3, glucagon immunoreactivity was detected in the glicentin-containing cells. These findings suggest that some of the polyps express characteristics of the fetal fundic mucosa, since glicentin and glucagon immunoreactivities in normal human stomach have been detected exclusively in the fetal fundus. ACTA PATHOL. JPN. 35: 831–840, 1985. 相似文献
15.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) affects the thyroid morphologically and/or functionally in adult animals. Recently, the National Toxicology Program conducted a 2-year gavage study of TCDD in female Harlan Sprague-Dawley rats. The only treatment-related alterations found in thyroid follicles were decreased luminal size and increased height of the follicular epithelial cells, without prominent protrusion into the lumen. The present study elucidated the nature of these follicular lesions. Thyroid glands of 10 rats each from the control, high (100 ng/kg/day)-dose, and stop-study (100 ng/kg/day, 30 weeks; vehicle to study termination) groups in the 2-year study were evaluated microscopically. Twenty randomly selected follicles were measured morphometrically in each animal. TCDD treatment significantly decreased the mean ratio of luminal/epithelial areas and increased the mean sectional epithelial height of the high-dose group compared to controls. Thyroid sections were immunostained with antibody against minichromosome maintenance (MCM) proteins, a novel cell-cycle biomarker. The MCM labeling index of the high-dose group was significantly higher than that of the control; however, the TUNEL labeling index was also higher in the high-dose group than the control. All data from the stop group were comparable to those from controls. These results indicate that the follicular cell response was hypertrophic and reversible. This information should contribute to diagnosis of nonneoplastic thyroid follicular lesions in rats. 相似文献
16.
Biological properties and gene expression associated with metastatic potential of human osteosarcoma 总被引:4,自引:0,他引:4
Nakano T Tani M Ishibashi Y Kimura K Park YB Imaizumi N Tsuda H Aoyagi K Sasaki H Ohwada S Yokota J 《Clinical & experimental metastasis》2003,20(7):665-674
Lung metastasis has a great influence on the prognosis of patients with osteosarcoma. We previously established two high-metastatic
sublines, M112 and M132, from the HuO9 human osteosarcoma cell line by in vivo selection. In this study, we newly isolated a high-metastatic subline, H3, and three low-metastatic sublines, L6, L12 and
L13, from HuO9 by the dilution plating method. Three high-metastatic sublines produced more than 200 metastatic nodules in
the lung, while three low-metastatic sublines produced no or few nodules after injection of 2 × 106 cells into the tail vein of nude mice. There were significant differences in the motility and invasiveness between high-
and low-metastatic sublines, whereas the growth rates in vitro and the tumorigenicity in vivo showed no correlation with their metastatic abilities. Early adherence to culture plates was significantly lower in two of
three low-metastatic sublines, which occupied smaller surface areas on the culture plates than other sublines did. Comparison
of the expression of 637 cancer-related genes by cDNA microarray revealed that seven genes were differentially expressed between
high- and low-metastatic sublines. Among them, five genes (AXL, TGFA, COLL7A1, WNT5A, and MKK6) were associated with adherence, motility, and/or invasiveness. These results suggest that the differences in motility/invasiveness
and adhesive abilities are key determinants of lung metastasis in osteosarcoma.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Iku Utsunomiya Kenji Tani Wanghua Gong Joost J. Oppenheim Ji Ming Wang 《European journal of immunology》1997,27(6):1406-1412
The C-C chemokine RANTES, a T lymphocyte chemoattractant, is considered an important mediator of inflammation, allergy, and host defense against HIV-1 infection. In this study, we investigated the modulation of binding of RANTES to T lymphocytes. Human peripheral blood CD3+ T cells, when freshly isolated from buffy-coat blood, expressed a considerable number of high-affinity binding sites for RANTES. These cells also showed significant chemotactic migration in response to RANTES in vitro. After 6–15 h incubation at 37°C, the binding of RANTES, but not of macrophage inflammatory protein-1α (MIP-1α) or of monocyte chemotactic protein-3 (MCP-3), consistently increased. Scatchard analyses indicated that the number of binding sites for RANTES increased about threefold by 15 h without any change in the affinity. The increase in RANTES binding was no longer detected by 24 h. This increase in the specific binding was mainly attributable to CD4+ T cells and was not associated with increased chemotactic activity of these cells in response to RANTES. Incubation with anti-CD3 antibody for 15 h markedly reduced the binding capability of T cells for RANTES and was associated with decreased chemotactic activity. On the other hand, when T cells were incubated with interleukin-2 (IL-2) for 1 week, the specific binding for all three C-C chemokines, RANTES, MIP-1α, and MCP-3 was markedly increased in comparison to cells cultured in the absence of IL-2. These results suggest that the expression of binding sites on T cells for RANTES is differentially modulated, indicating the existence of novel receptors for RANTES that do not bind MIP-1α. 相似文献
18.
Sarcomatoid carcinomas involving the intestinal tract are rare and usually associated with poor prognosis. We report a case of sarcomatoid carcinoma of the ileum, diagnosed in a 61-year-old man. The patient presented with acute intestinal occlusion. Surgical resection of the ileum was performed. At macroscopic examination, two large polypoid masses were found. Frozen section examination suggested the diagnosis of malignant stromal tumor. At histological examination, both tumors were formed by pleiomorphic, large spindle cells, presenting numerous mitoses and marked nuclear atypia. Immunohistochemical examination showed that tumor cells coexpressed vimentin and epithelial markers (cytokeratins, EMA). The final diagnosis was monomorphic sarcomatoid carcinoma. The patient deceased with metastatic disease after 3 months of follow-up. This report underlines the potential diagnostic problems raised by this unusual type of carcinoma and emphasizes the role of immunohistochemistry in assessing the correct diagnosis. 相似文献
19.
20.
S Aotsuka T Funahashi N Tani M Okawa-Takatsuji M Kinoshita R Yokohari 《Clinical and experimental immunology》1990,79(2):215-220
Antibodies to dsDNA are characteristically present in serum from patients with systemic lupus erythematosus (SLE), and have been shown to have the capacity to react with various molecules bearing repeating negative charges. After a number of polymeric or monomeric molecules with differently charged groups and hydrophobic molecules had been coupled covalently as ligands on cellulose gel, the adsorption capacities of the ligands for anti-dsDNA antibodies were evaluated. It was found that gels coupled with polyanionic dextran sulphate (DXS) and polyacrylic acid (PA) and monoanionic sulphanilic acid (SA) absorbed anti-dsDNA antibodies effectively. DXS gel also adsorbed antibodies to ssDNA and heparan sulphate, antigens with repeating negatively charged moieties, while no ligand was able to adsorb anti-nRNP antibodies. The finding that DXS gels adsorbed anti-dsDNA antibody in proportion to their charge density, and that the interaction between anti-dsDNA and DXS gel is broken readily by an increase in ionic strength, indicated that the binding is ionic in nature. Moreover, virtually all F(ab')2 anti-dsDNA became adsorbed onto the DXS gels, suggesting that the binding occurred via specific antigen-binding sites on the antibody molecule. Binding of these polyanion-binding autoantibodies with anionic sites in the glomerular basement membrane may therefore cause the tissue damage observed in SLE. 相似文献