全文获取类型
收费全文 | 6626篇 |
免费 | 295篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 135篇 |
儿科学 | 132篇 |
妇产科学 | 281篇 |
基础医学 | 868篇 |
口腔科学 | 52篇 |
临床医学 | 636篇 |
内科学 | 1950篇 |
皮肤病学 | 63篇 |
神经病学 | 619篇 |
特种医学 | 116篇 |
外科学 | 766篇 |
综合类 | 47篇 |
一般理论 | 1篇 |
预防医学 | 268篇 |
眼科学 | 111篇 |
药学 | 537篇 |
中国医学 | 12篇 |
肿瘤学 | 378篇 |
出版年
2023年 | 35篇 |
2022年 | 177篇 |
2021年 | 303篇 |
2020年 | 95篇 |
2019年 | 140篇 |
2018年 | 154篇 |
2017年 | 106篇 |
2016年 | 127篇 |
2015年 | 147篇 |
2014年 | 239篇 |
2013年 | 279篇 |
2012年 | 490篇 |
2011年 | 488篇 |
2010年 | 263篇 |
2009年 | 215篇 |
2008年 | 400篇 |
2007年 | 466篇 |
2006年 | 472篇 |
2005年 | 448篇 |
2004年 | 429篇 |
2003年 | 425篇 |
2002年 | 372篇 |
2001年 | 63篇 |
2000年 | 46篇 |
1999年 | 55篇 |
1998年 | 43篇 |
1997年 | 52篇 |
1996年 | 47篇 |
1995年 | 18篇 |
1994年 | 27篇 |
1993年 | 16篇 |
1992年 | 27篇 |
1991年 | 22篇 |
1990年 | 28篇 |
1989年 | 28篇 |
1988年 | 26篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 10篇 |
1975年 | 8篇 |
1973年 | 10篇 |
1970年 | 10篇 |
1969年 | 11篇 |
排序方式: 共有6972条查询结果,搜索用时 0 毫秒
41.
Wicherek L Mak P Klimek M Banaś T 《European journal of obstetrics, gynecology, and reproductive biology》2007,131(1):97-100
OBJECTIVE: Well-known natural unspecific antimicrobial factors acting in the vagina are additionally reinforced during menstrual bleeding by hemocidins--a recently discovered novel class of microbicidal peptides generated proteolytically from hemoglobin. The aim of the presented research was to investigate the relation between the average length of menstrual bleeding and the frequency of urogenital infections. We expected that the shorter menstrual bleeding might increase the risk of urogenital infections because is synonymous with the shorter period of exposition on bactericidal action of hemocidins. STUDY DESIGN: The study contains statistical analysis of an average declared length of menstrual bleeding in the group of 267 young, sexually active women with the symptoms of urogenital infections. The control group consisted of 300 young healthy women. RESULTS: The length of menstrual bleeding in the group of patients with urogenital infections (average 4.35 days) was statistically significantly shorter than in the control group (average 4.95 days). The average length of the menstrual cycle was equal and counted ca. 28 days in both groups. CONCLUSION: The length of menstrual bleeding seems to be a significant factor in the vaginal ecology maintenance. 相似文献
42.
The process of foaming poly(caprolactone)-based composite materials using supercritical carbon dioxide was analyzed, especially in terms of the biocompatibility of the resultant materials. The influence of foaming process conditions and composite material properties on the functional properties of polymer solid foams, intended for artificial scaffolds for bone cell culture, was investigated. The relationship between wettability (contact angle) and water absorption rate as a result of the application of variable conditions for the production of porous structures was presented. For the evaluation of potential cytotoxicity, the MTT and PrestoBlue tests were carried out, and animal cells (mouse fibroblasts) were cultured on the materials for nine days. There was no toxic effect of composite materials made of poly(caprolactone) containing porogen particles: hydroxyapatite, crystalline nanocellulose, and graphene oxide on cells. The desired effect of the porogens used in the foaming process on the affinity of cells to the resultant material was demonstrated. The tested materials have been shown to be biocompatible and suitable for applications in biomedical engineering. 相似文献
43.
Dorota Dziurka Adam Derkowski Marek Wieruszewski Marcin Kuliski Radosaw Mirski 《Materials》2022,15(11)
Glulam beams are increasingly used in the construction industry because of their high strength and the possibility of using round timber with smaller cross-sections. The load-bearing capacity of beams is strongly related to the quality of the outer layers and, in the case of wood, especially the tension zones. For these reasons, this study decided to replace the outer lamella with tensile plywood. The produced beams were subjected to static bending strength and modulus of elasticity evaluation. It was shown that the best static bending strength values were obtained for beams containing plywood in the tension layer. However, the change in structure in the tension zone of beams made of glued laminated timber results not only in an increase in the load capacity of elements produced in this way but also in a decrease in the range/range of the obtained results of bending strength. This way of modifying the construction of glued laminated beams allows a more rational use of available pine timber. 相似文献
44.
Prognostic value of selected platelet parameters of patients operated for non-small cell lung cancer
Mariusz ochowski Marek Rbowski Justyna Chaubiska-Fendler Izabela Zawadzka Barbara ochowska Bartosz Cielik-Wolski Jzef Kozak 《Journal of thoracic disease》2022,14(5):1374
BackgroundPlatelets play a vital role in the neoplastic process. Platelet parameters are hence an important source of information concerning ongoing neoplastic disease. The aim of the study is to assess the impact of selected platelet parameters on the survival of patients with non-small cell lung cancer (NSCLC).MethodsThe study included 532 (174 female and 358 male) patients aged 36–84 years (mean age 63.6 years) operated on due to NSCLC, staged IA–IIIA. Before the operation, all patients received a blood morphology test. The following parameters were subjected to statistical analysis: platelet count, mean platelet volume (MPV) parameter, platelet distribution width (PDW) parameter, platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation (SII) index. These findings were compared with the clinical data of the patients, and the probability of overall survival was analyzed.ResultsThe univariate analysis revealed a correspondence between PDW, MPV, PLR and SII index and patient survival. The multivariate analysis including patient clinical data found the following factors to have negative prognostic value for patients operated on due to NSCLC: male sex, advancement stage of neoplastic disease and Charlson Comorbidity Index (CCI) above 4, and PLR >144.ConclusionsPDW value, PLR and SII index are independent prognostic factors. In the multi-factor model, male sex, the advancement stage of the neoplastic disease, CCI above 4 and PLR lower than 144 had the greatest prognostic value. 相似文献
45.
46.
47.
48.
Agnieszka Mazur Anna Szylling Teresa Bielecka Marek Kulus 《The Journal of asthma》2013,50(10):1147-1155
Objective: The prevalence of allergic diseases has reached epidemic proportions in the Western world. Although farm-living has been associated with a lower prevalence of asthma and atopy, a marked increase in atopy among rural populations after accession to the European Union has been recently reported in Poland. Here, we aimed to investigate the effect of living environment on the prevalence of atopy and allergic diseases in Polish children. Methods: 400 schoolchildren aged 10–14 years from the capital city (223) and from traditional rural part of the country (177) were recruited from June to November 2011. Data on allergic diseases and symptoms were collected by means of questionnaire and physical examination. Atopy was assessed based on skin prick tests (SPTs) reactivity to inhalant allergens in 350 children. Results: A high discrepancy between the prevalence of allergic symptoms (46.7%) and doctor-diagnosed allergic diseases (25%) was demonstrated (p < 0.0001). Urban children had a higher overall prevalence of allergic diseases and atopy than children living in rural areas, 29.3% versus 17.1% (p = 0.007) and 33.5% versus 20% (p = 0.0045), respectively. However, no significant differences in the rates of particular allergic diseases were noted (p > 0.05). There was higher SPT positivity to trees, grass, corn, weeds, animal dander, and molds in urban children (p < 0.05). Conclusions: Our data support the protective effect of farm-living on the prevalence of atopy and overall allergic diseases, albeit not on particular allergic diseases, in children in Poland. The underlying mechanisms are not identified, but current socioeconomic changes may be responsible. 相似文献
49.
Altered NKG2D function in NK cells induced by chronic exposure to NKG2D ligand-expressing tumor cells 总被引:11,自引:0,他引:11 下载免费PDF全文
NKG2D is an activation receptor that allows natural killer (NK) cells to detect diseased host cells. The engagement of NKG2D with corresponding ligand results in surface modulation of the receptor and reduced function upon subsequent receptor engagement. However, it is not clear whether in addition to modulation the NKG2D receptor complex and/or its signaling capacity is preserved. We show here that the prolonged encounter with tumor cell-bound, but not soluble, ligand can completely uncouple the NKG2D receptor from the intracellular mobilization of calcium and the exertion of cell-mediated cytolysis. However, cytolytic effector function is intact since NKG2D ligand-exposed NK cells can be activated via the Ly49D receptor. While NKG2D-dependent cytotoxicity is impaired, prolonged ligand exposure results in constitutive interferon gamma (IFNgamma) production, suggesting sustained signaling. The functional changes are associated with a reduced presence of the relevant signal transducing adaptors DNAX-activating protein of 10 kDa (DAP-10) and killer cell activating receptor-associated protein/DNAX-activating protein of 12 kDa (KARAP/DAP-12). That is likely the consequence of constitutive NKG2D engagement and signaling, since NKG2D function and adaptor expression is restored to normal when the stimulating tumor cells are removed. Thus, the chronic exposure to tumor cells expressing NKG2D ligand alters NKG2D signaling and may facilitate the evasion of tumor cells from NK cell reactions. 相似文献
50.