全文获取类型
收费全文 | 4189篇 |
免费 | 168篇 |
国内免费 | 94篇 |
专业分类
耳鼻咽喉 | 231篇 |
儿科学 | 260篇 |
妇产科学 | 52篇 |
基础医学 | 492篇 |
口腔科学 | 80篇 |
临床医学 | 188篇 |
内科学 | 769篇 |
皮肤病学 | 37篇 |
神经病学 | 278篇 |
特种医学 | 68篇 |
外国民族医学 | 2篇 |
外科学 | 436篇 |
综合类 | 301篇 |
预防医学 | 143篇 |
眼科学 | 105篇 |
药学 | 356篇 |
中国医学 | 66篇 |
肿瘤学 | 587篇 |
出版年
2023年 | 59篇 |
2022年 | 100篇 |
2021年 | 134篇 |
2020年 | 165篇 |
2019年 | 386篇 |
2018年 | 375篇 |
2017年 | 153篇 |
2016年 | 109篇 |
2015年 | 145篇 |
2014年 | 307篇 |
2013年 | 337篇 |
2012年 | 127篇 |
2011年 | 150篇 |
2010年 | 83篇 |
2009年 | 122篇 |
2008年 | 123篇 |
2007年 | 147篇 |
2006年 | 90篇 |
2005年 | 60篇 |
2004年 | 78篇 |
2003年 | 35篇 |
2002年 | 25篇 |
2001年 | 29篇 |
2000年 | 42篇 |
1999年 | 28篇 |
1998年 | 27篇 |
1997年 | 29篇 |
1996年 | 40篇 |
1995年 | 29篇 |
1994年 | 24篇 |
1993年 | 24篇 |
1992年 | 23篇 |
1991年 | 29篇 |
1990年 | 14篇 |
1989年 | 17篇 |
1988年 | 24篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 97篇 |
1984年 | 110篇 |
1983年 | 74篇 |
1982年 | 87篇 |
1981年 | 73篇 |
1980年 | 65篇 |
1979年 | 53篇 |
1978年 | 41篇 |
1977年 | 32篇 |
1976年 | 43篇 |
1975年 | 24篇 |
1974年 | 16篇 |
排序方式: 共有4451条查询结果,搜索用时 15 毫秒
21.
Göran K. Hansson Göran Bondjers Anders Bylock Lena Hjalmarsson 《Experimental and molecular pathology》1980,33(3):302-315
Immunoelectron microscopy with peroxidase-conjugated Fab fragments of anti-IgG was used for studying the localization of IgG in the aortic endothelium and subendothelial intima of atherosclerotic and nonatherosclerotic rabbits. Small amounts of IgG were found in the cell coat, in caveolae and vesicles, and also in intercellular clefts of endothelial cells from normocholesterolemic rabbits. Injured endothelial cells exhibited prominent accumulations of IgG in the cytoplasmic matrix, possibly due to leakage through plasma membrane defects. In atherosclerotic lesions from hypercholesterolemic rabbits, there was a striking increase in the amount of IgG-reactive material in the cell coat and vesicles of intact endothelial cells. Also in these animals, injured endothelial cells were characterized by a cytoplasmic IgG accumulation. There were prominent IgG depositions in the subendothelial zone of the lesions. IgG was adhering to collagen fibers, and also coating the surfaces of subendothelial foam cells. The pathophysiological significance of an interaction between such intimal IgG and phagocytes is discussed. 相似文献
22.
目的 探讨能否直接利用肿瘤细胞膜进行表皮生长因子受体 (Epidermalgrowthfactorreceptor,EGFR)催化活性检测。方法 首先筛选出EGFR基因表达水平相对较高的细胞株MDA MB 2 31,通过差速离心制备细胞膜 ,采用Westernblotting检测EGFR催化磷酸化的程度。结果 底物被磷酸化 ,加入特异性拮抗剂AG14 78后 ,磷酸化被抑制。结论 利用肿瘤细胞膜检测EGFR活性的设想是成立的 ,并且其方法简便、经济。 相似文献
23.
Birgitta Swolin Aleksander Weinfeld Johan Waldenström Jan Westin 《Cancer Genetics and Cytogenetics》1983,9(3):197-209
Of 33 consecutive patients with chronic myelocytic leukemia, examined during metamorphosis, 82% showed chromosome abnormalities in addition to the Ph1. Aberrations most frequently encountered were +8 (39%), +22q - (30%), and i(17q) (18%). Translocations other than the Ph1 were observed in four cases and - Y clones in four cases. Discrepancies in the cytogenetic pattern between bone marrow and extramedullary tissues or blood were noted in a total of 15 patients. In six cases, transformation occurred in extramedullary organs at a time when it was not present in the marrow. In three cases the bone marrow transformation was preceded by a lymph node blastic infiltrate; in one case, by a skin infiltrate; and in one case, by a subdural blastoma. Clonal abnormalities additional to the Ph1 were identified in the tumor tissue from all these cases. Patients with primary extramedullary transformation tended to have a lower median age at onset of metamorphosis, shorter survival, and higher incidence of chromosome abnormalities than the cases without extramedullary involvement. Patients with only Ph1-positive cells and no other anomalies had a slightly longer duration of metamorphosis and longer total survival. Basophilia and thrombocytopenia were more marked in cases with i(17q) than in the rest of the series. 相似文献
24.
Yukichi Tanaka 《Virchows Archiv : an international journal of pathology》1987,410(2):125-132
Summary The present study concerns the immunocytochemical localization of S-100 protein and subunits in the cells of human lymphoreticular tissue and their related tumours. The subunit is mainly localized in dendritic cells, most likely the dendritic reticulum cells (DRCs) located within the germinal centers, while the subunit is mainly localized in the interdigitating reticulum cells (IRCs) in the paracortical area and in Histiocytosis X cells. No immunoreactivity for either subunit was found in the majority of normal lymphocytes, macrophages, malignant lymphoma cells, or xanthoma cells.The DRCs and IRCs are generally considered to show different distribution in the lymphoid tissues and demonstrate some difference in their immunocytochemical and enzyme-histochemical features. It is suggested that S-100 subunits can be used as useful markers for these two types of dendritic cells and investigation of these subunits may provide more information for the study of human lymphoreticular system. 相似文献
25.
In this second of three articles exploring Engel's biopsychosocial model, five case histories illustrate how psychological factors, sometimes related to organic trauma or illness, may precipitate psychiatric conditions. The patients’ disorders, and their management by a consultation-liaison team, demonstrate the interaction of biologic, psychological, and social systems in assessment and treatment of disease. 相似文献
26.
Summary Presence and distribution of S-100 protein (S-100), neuron-specific enolase (NSE), cytokeratin polypeptides, glial fibrillary acidic protein (GFAP), vimentin, actin, lysozyme and pituitary hormones (prolactin, hGH, ACTH, -FSH, -LH, -TSH, alpha subunit) in folliculo-stellate cells (FSC) were studied in seven normal human pituitary glands and 28 pituitary adenomas using peroxidase-antiperoxidase and the avidin-biotin immunohistochemical techniques. Approximately 5% of the cells of the adenohypophysis were agranular, non-hormon-producing FSC most of which showed a conspicuous and strong reaction with S-100 antibodies but some were, in addition, GFAP- and vimentin-positive. In contrast to endocrine cells (EC), FSC were not decorated by antibodies to NSE or cytokeratins. In addition to supportive functions, these cells, due to their close special relationship to EC, seem to have transport and other metabolic functions yet to be elucidated. By their S-100 reactivity and their distribution FSC are comparable to glial cells of the central and schwann and satellite cells of the peripheral nervous system (PNS) as well as to supportive cells in neuroendocrine organs and related tumors (e.g., pheochromocytomas, paragangliomas, carcinoids). With one exception, S-100 reactive FSC were not found in pituitary adenomas. The immunohistochemical demonstration of S-100 protein in pituitary tissue is, therefore, a reliable aid in the discrimination between adenomas and normal pituitary tissue, particularly in small and poorly preserved specimens. In one adenoma FSC were found in addition to ACTH-producing tumor cells. This seems to be an extremely rare event suggesting a combination tumor.Supported in part by Fonds zur Förderung der wissenschaftlichen Forschung (no. 4708) to H. Denk 相似文献
27.
《Vaccine》2022,40(44):6422-6430
BackgroundRotavirus vaccine (Rotarix®) was introduced in Mozambique through its Expanded Program of Immunization in September 2015. We assessed the impact of rotavirus vaccination on childhood gastroenteritis-associated hospitalizations post-vaccine introduction in a high HIV prevalence rural setting of southern Mozambique.MethodsWe reviewed and compared the trend of hospitalizations (prevalence) and incidence rates of acute gastroenteritis (AGE), and rotavirus associated-diarrhea (laboratory confirmed rotavirus) in pre- (January 2008–August 2015) and post-rotavirus vaccine introduction periods (September 2015–December 2020), among children <5 years of age admitted to Manhiça District Hospital.ResultsFrom January 2008 to December 2020, rotavirus vaccination was found to contribute to the decline of the prevalence of AGE from 19% (95% CI: 18.14–20.44) prior to the vaccine introduction to 10% (95% CI: 8.89–11.48) in the post-introduction period, preventing 40% (95 % IE: 38–42) and 84% (95 % IE: 80–87) of the expected AGE and laboratory confirmed rotavirus cases, respectively, among infants. Similarly, the overall incidence of rotavirus was 11.8-fold lower in the post-vaccine introduction period (0.4/1000 child-years-at-risk [CYAR]; 95% CI: 0.3–0.6) compared with the pre-vaccination period (4.7/1000 CYAR; 95% CI: 4.2–5.1) with the highest reduction being observed among infants (16.8-fold lower from the 15.1/1000 CYAR in the pre-vaccine to 0.9/1000 CYAR in the post-vaccine eras).ConclusionsWe documented a significant reduction in all-cause diarrhea hospitalizations and rotavirus positivity after vaccine introduction demonstrating the beneficial impact of rotavirus vaccination in a highly vulnerable population. 相似文献
28.
Summary The immunohistochemical distribution of S-100 protein in patients with Down's syndrome was investigated as part of a study aimed at ascertaining a possible involvement in the syndrome (trisomy 21) of this protein, which has recently been shown to be coded in chromosome 21. No appreciable differences in the cell distribution of the antigen could be observed between patients with Down's syndrome and normal subjects. The possibility of an overexpression or abnormal expression of the molecule as a consequence of chromosome 21 triplication, not detectable by immunocytochemical methods alone, remains to be investigated.Supported in part by grants from Consiglio Nazionale delle Ricerche and Ministero della Pubblica Istruzione to F. M. and L. L. 相似文献
29.
Angela M. Otto 《Journal of cancer research and clinical oncology》1994,120(5):286-292
The growth-inhibitory effects of combining interferons (IFN) with platinum(II) complexes were tested with the aim of comparing these in cultures of estrogen-receptor(ER)-negative MDA-MB231 and ER-positive MCF-7 breast cancer cell lines. Another aim was to test whether IFN as a biological response modifier could enhance the effect of the Pt complexes in vitro in an attempt to find an explanation for their more potent antitumor effects in in vivo models. Here it is shown that in both cell lines the combinations of different IFN with all three Pt complexes generally resulted in additive growth inhibition, as calculated by the product of the fraction of surviving cells obtained with each compound alone. Moreover, in MCF-7 cells natural IFN (nIFN) combined with aqua[meso-1,2-bis-(2,6-dichloro-4-hydroxyphenyl)ethylenediamine]sulfatoplatinum(II) (meso-6-Pt) resulted in synergistic inhibition. This synergy could be attributed to the estrogenic property of meso-6-Pt, since the ligand and estradiol also enhanced the inhibitory effect of nIFN. In contrast, the combination of recombinant IFN and meso-6-Pt was antagonistic in MDA-MB231 cells. These results show that, in spite of the similar responses of the ER-negative and ER-positive cells to each compound alone, these cells show unexpected differences in their sensitivity to combinations of IFN and the new Pt complex meso-6-Pt.Abbreviations ER
estrogen receptor
- IFN
interferon(s)
- nIFN
natural interferon
- rIFN
recombinant interferon
- meso-4-Pt
aqua[meso-1,2-bis(2,6-difluoro-3-hydroxyphenyl)ethylenediamine]sulfatoplatinum(II)
- meso-6-Pt
aqua[meso-1,2-bis-(2,6-dichloro-4-hydroxyphenyl) ethylenediamine]sulfatoplatinum(II) 相似文献
30.
Summary In order to study the cellular origin of muscularization in non-muscular arterioles of the lung, the pulmonary vascular pericytes-culture
was established. The terminal lung tissue of the rat was taken out and minced. Then 0.5 % of type IV collagenase solution
was added for digestion and the microvascular segments were obtained by screening. The targeted cells were cultured by “selective
conditioned media”. Under phase-contrast microscope, the cultured cells were large in size with ragged margin and numerous
pseudopodia, which imparted tubule-like structure. There was no contact inhibition in growing cells, so multiple layers developed.
When they were confluent, there were morphologically no “hillock and dale” growth pattern as in smooth muscle cells or “weave-like”
pattern as in fibroblasts. The ultrastructure of cultured cells showed numerous digital processes, moderate amount of rough
and smooth endoplasmic reticulum, rich Golgi’s apparatus, microfilaments, few lysosomes without myofilaments and dense bodies.
Immunohistochemical staining revealed that the cultured pericytes had same kind of cellular skeletal protein, α-SM-actin,
like smooth muscle cells. The cultured cells also exhibited positive reaction to CD34 antigen and S-100 antigen, which were negative in smooth muscle cells and fibroblasts. The cell growth pattern, ultrastructure
and immunological phenotype suggested that the cultured cells had characteristics of vascular pericytes. Pericytes are one
of the components of microvascular cells, and the establishment ofin vitro culture technique of pericytes is of significance for further exploration of the muscularization of non-muscular arterioles
in lung and the mechanism of structural remodeling of pulmonary vessels.
This project was supported by the grant of National Nature Sciences Foundation of China (No. 39570289). 相似文献