全文获取类型
收费全文 | 1029篇 |
免费 | 91篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 42篇 |
妇产科学 | 18篇 |
基础医学 | 122篇 |
口腔科学 | 15篇 |
临床医学 | 91篇 |
内科学 | 163篇 |
皮肤病学 | 7篇 |
神经病学 | 115篇 |
特种医学 | 147篇 |
外科学 | 224篇 |
综合类 | 12篇 |
预防医学 | 64篇 |
眼科学 | 1篇 |
药学 | 57篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 19篇 |
出版年
2022年 | 10篇 |
2020年 | 13篇 |
2019年 | 18篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 11篇 |
2015年 | 16篇 |
2013年 | 27篇 |
2012年 | 25篇 |
2011年 | 21篇 |
2010年 | 29篇 |
2009年 | 36篇 |
2008年 | 28篇 |
2007年 | 42篇 |
2006年 | 35篇 |
2005年 | 25篇 |
2004年 | 25篇 |
2003年 | 31篇 |
2002年 | 24篇 |
2001年 | 24篇 |
2000年 | 24篇 |
1999年 | 35篇 |
1998年 | 26篇 |
1997年 | 21篇 |
1996年 | 33篇 |
1995年 | 24篇 |
1994年 | 29篇 |
1993年 | 23篇 |
1992年 | 16篇 |
1991年 | 13篇 |
1990年 | 23篇 |
1989年 | 34篇 |
1988年 | 33篇 |
1987年 | 27篇 |
1986年 | 24篇 |
1985年 | 19篇 |
1984年 | 22篇 |
1983年 | 20篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 18篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 17篇 |
1975年 | 17篇 |
1974年 | 12篇 |
1973年 | 11篇 |
1970年 | 12篇 |
1966年 | 7篇 |
排序方式: 共有1130条查询结果,搜索用时 15 毫秒
31.
Austin C. Cao Zachary M. Nimmo Natasha Mirza Noam A. Cohen Robert M. Brody Richard L. Doty 《世界耳鼻咽喉头颈外科杂志(英文)》2022,8(3):249
BackgroundSmell and taste loss are highly prevalent symptoms in coronavirus disease 2019 (COVID‐19), although few studies have employed objective measures to quantify these symptoms, especially dysgeusia. Reports of unrecognized anosmia in COVID‐19 patients suggests that self‐reported measures are insufficient for capturing patients with chemosensory dysfunction.ObjectivesThe purpose of this study was to quantify the impact of recent COVID‐19 infection on chemosensory function and demonstrate the use of at‐home objective smell and taste testing in an at‐risk population of healthcare workers.MethodsTwo hundred and fifty healthcare workers were screened for possible loss of smell and taste using online surveys. Self‐administered smell and taste tests were mailed to respondents meeting criteria for elevated risk of infection, and one‐month follow‐up surveys were completed.ResultsAmong subjects with prior SARS‐CoV‐2 infection, 73% reported symptoms of olfactory and/or gustatory dysfunction. Self‐reported smell and taste loss were both strong predictors of COVID‐19 positivity. Subjects with evidence of recent SARS‐CoV‐2 infection (<45 days) had significantly lower olfactory scores but equivalent gustatory scores compared to other subjects. There was a time‐dependent increase in smell scores but not in taste scores among subjects with prior infection and chemosensory symptoms. The overall infection rate was 4.4%, with 2.5% reported by PCR swab.ConclusionHealthcare workers with recent SARS‐CoV‐2 infection had reduced olfaction and normal gustation on self‐administered objective testing compared to those without infection. Rates of infection and chemosensory symptoms in our cohort of healthcare workers reflect those of the general public. 相似文献
32.
Recent studies of Alzheimer's disease patients have demonstrated (a) marked structural and biochemical alterations in brain regions associated with olfactory function (including the olfactory bulb and entorhinal cortex) and (b) decrements in the ability to identify odorants. In light of such findings, we administered the University of Pennsylvania Smell Identification Test (UPSIT) and a forced-choice phenyl ethyl alcohol odor detection threshold test to a relatively large number of patients diagnosed, on the basis of stringent criteria, as having mild to moderately severe Alzheimer's disease. Compared to age-, gender-, and race-matched normal controls, these individuals evidenced consistent and marked decrements on both types of olfactory tests (ps less than 0.001). Surprisingly few of the patients were aware of their disorder, despite its appearance early in the disease process. These findings indicate that both odor identification and odor detection problems are present in dementia of the Alzheimer's type, and raise the possibility that the odor identification problem may be secondary to the odor detection problem. 相似文献
33.
Adel M. A. Mohamed Ehab Samuel Yasser Zedan Agnes M. Samuel Herbert W. Doty Fawzy H. Samuel 《Materials》2022,15(4)
The present study was undertaken to examine the effect of iron, manganese, copper and magnesium on the microstructural characteristics of Al-11%Si-2%Cu-Mg-based alloy referred to as 396 under different working conditions. The results show that strontium (Sr) has high affinity to react with magnesium (Mg), resulting in reduced effectiveness as eutectic silicon modifier or age hardening agent. In addition, Sr alters the sequence of the precipitation of the α-AlFeMnSi phase from post-eutectic to pro-eutectic which would harden the soft α-Aluminum matrix. The mechanism is still under investigation. The interactions between iron (Fe) and Mg and Sr-Mg result in the formation of serval dissolvable intermetallics during the solutionizing treatment such as β-AlFeSi, π-AlFeMgSi and Q-AlMgSiCu phases. The study also emphasizes the role of modification and grain refining as well as intermetallics in porosity formation and hardness of samples aged in the temperature range 155–240 °C. 相似文献
34.
进一步研究了抗三尖杉酯碱的HL-60细胞(HR20)抗细胞凋亡的机制及该抗性和抗药性的关系。结果表明,环孢菌素A(CsA)20,10μg·ml-1诱导HL-60细胞发生凋亡,而阻断HR20细胞于G1期,就不能诱导细胞发生凋亡。低浓度的CsA明显增加柔红霉素在HR20细胞内的积聚,其逆转抗药性作用与阻断细胞周期运行无关。CsA10μg·ml-1处理HR20细胞,可引起50kDa的蛋白质高度磷酸化。结果提示:环孢菌素A阻断抗三尖杉酯碱的HL-60细胞于G1期,而诱导敏感的HL-60细胞发生凋亡,其阻断作用与抗药性无关。 相似文献
35.
36.
Leisha Diane Nolen Lynda Osadebe Jacques Katomba Jacques Likofata Daniel Mukadi Benjamin Monroe Jeffrey Doty Lem's Kalemba Jean Malekani Joelle Kabamba Pierre Lokwa Bomponda Jules Inonga Lokota Marcel Pie Balilo Toutou Likafi Robert Shongo Lushima Jean-Jacques Muyembe Tamfum Emile Wemakoy Okitolonda Andrea M. McCollum Mary G. Reynolds 《The American journal of tropical medicine and hygiene》2015,93(2):410-415
An increased incidence of monkeypox (MPX) infections in the Democratic Republic of the Congo was noted by the regional surveillance system in October 2013. Little information exists regarding how MPX is introduced into the community and the factors associated with transmission within the household. Sixty-eight wild animals were collected and tested for Orthopoxvirus. Two of three rope squirrels (Funisciurus sp.) were positive for antibodies to Orthopoxviruses; however, no increased risk was associated with the consumption or preparation of rope squirrels. A retrospective cohort investigation and a case–control investigation were performed to identify risk factors affecting the introduction of monkeypox virus (MPXV) into the community and transmission within the home. School-age males were the individuals most frequently identified as the first person infected in the household and were the group most frequently affected overall. Risk factors of acquiring MPXV in a household included sleeping in the same room or bed, or using the same plate or cup as the primary case. There was no significant risk associated with eating or processing of wild animals. Activities associated with an increased risk of MPXV transmission all have potential for virus exposure to the mucosa. 相似文献
37.
Brunner G; Metz CN; Nguyen H; Gabrilove J; Patel SR; Davitz MA; Rifkin DB; Wilson EL 《Blood》1994,83(8):2115-2125
Basic fibroblast growth factor (bFGF) is a hematopoietic cytokine that stimulates stromal and stem cell growth. It binds to a glycosylphosphatidylinositol (GPI)-anchored heparan sulfate proteoglycan on human bone marrow (BM) stromal cells. The bFGF- proteoglycan complex is biologically active and is released by addition of exogenous phosphatidylinositol-specific phospholipase C. In this study, we show the presence of an endogenous GPI-specific phospholipase D (GPI-PLD) that releases the bFGF-binding heparan sulfate proteoglycan and the variant surface glycoprotein (a model GPI-anchored protein) from BM cultures. An involvement of proteases in this process is unlikely, because released proteoglycan contained the GPI anchor component, ethanol-amine, and protease inhibitors did not diminish the release. The mechanism of release is likely to involve a GPI-PLD and not a GPI-specific phospholipase C, because the release of variant surface glycoprotein did not reveal an epitope called the cross- reacting determinant that is exposed by phospholipase C-catalyzed GPI anchor cleavage. In addition, phosphatidic acid (which is specifically a product of GPI-PLD-catalyzed anchor cleavage) was generated during the spontaneous release of the GPI-anchored variant surface glycoprotein. We also detected GPI-PLD-specific enzyme activity and mRNA in BM cells. Therefore, we conclude that an endogenous GPI-PLD releases bFGF-heparan sulfate proteoglycan complexes from human BM cultures. This mechanism of GPI anchor cleavage could be relevant for mobilizing biologically active bFGF in BM. An endogenous GPI-PLD could also release other GPI-anchored proteins important for hematopoiesis and other physiologic processes. 相似文献
38.
39.
40.
目的:评估人工流产(指手术流产)对乳腺癌危险性的可能影响。方法:研究在上海267040例妇女的一项乳房自我检查随机试验的队列人群中进行,由队列研究和巢式病例对照研究两部分组成。结果:依据基线调查表采集的资料分析,人工流产不增加乳腺癌危险性。调整潜在的混淆因素后,OR=1.06(95%CI:0.91~1.25)。人工流产次数增加无危险性趋势增加。从更详细的652例乳腺癌病例和694例对照资料分析,得出相似的结果。人工流产发生在首次生育后不增加危险性;少数妇女在首次生育前人工流产以及妊娠13周后人工流产,虽然被观察到危险性有增加,但无显著性统计学意义。结论:在中国,人工流产不是乳腺癌发生的重要原因。 相似文献