全文获取类型
收费全文 | 17445篇 |
免费 | 1031篇 |
国内免费 | 655篇 |
专业分类
耳鼻咽喉 | 173篇 |
儿科学 | 577篇 |
妇产科学 | 384篇 |
基础医学 | 1247篇 |
口腔科学 | 148篇 |
临床医学 | 1614篇 |
内科学 | 4952篇 |
皮肤病学 | 198篇 |
神经病学 | 870篇 |
特种医学 | 288篇 |
外科学 | 915篇 |
综合类 | 2789篇 |
一般理论 | 2篇 |
预防医学 | 2527篇 |
眼科学 | 309篇 |
药学 | 780篇 |
8篇 | |
中国医学 | 994篇 |
肿瘤学 | 356篇 |
出版年
2024年 | 28篇 |
2023年 | 357篇 |
2022年 | 762篇 |
2021年 | 997篇 |
2020年 | 979篇 |
2019年 | 752篇 |
2018年 | 712篇 |
2017年 | 629篇 |
2016年 | 692篇 |
2015年 | 741篇 |
2014年 | 1387篇 |
2013年 | 1487篇 |
2012年 | 1097篇 |
2011年 | 1223篇 |
2010年 | 990篇 |
2009年 | 846篇 |
2008年 | 761篇 |
2007年 | 682篇 |
2006年 | 522篇 |
2005年 | 464篇 |
2004年 | 388篇 |
2003年 | 407篇 |
2002年 | 287篇 |
2001年 | 252篇 |
2000年 | 174篇 |
1999年 | 151篇 |
1998年 | 111篇 |
1997年 | 132篇 |
1996年 | 96篇 |
1995年 | 76篇 |
1994年 | 80篇 |
1993年 | 49篇 |
1992年 | 46篇 |
1991年 | 47篇 |
1990年 | 37篇 |
1989年 | 24篇 |
1987年 | 33篇 |
1985年 | 55篇 |
1984年 | 62篇 |
1983年 | 40篇 |
1982年 | 39篇 |
1981年 | 45篇 |
1980年 | 61篇 |
1979年 | 48篇 |
1978年 | 31篇 |
1976年 | 29篇 |
1974年 | 23篇 |
1973年 | 33篇 |
1972年 | 25篇 |
1971年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Shuji Takeshita Masanori Hosokawa Mika Irino Keiichi Higuchi Katsuji Shimizu Kimio Yasuhira Toshio Takeda 《Mechanisms of ageing and development》1982,20(1):13-23
Morphological studies on spontaneous systemic amyloidosis were conducted on 222 senescence-accelerated mice (SAM) (P) and on 150 mice in the senescence-resistant series (R).Among the pathologic findings, amyloidosis showed the highest incidence in both SAM (79.7%) and R (32.7%) Although an extensive deposition of amyloid was evident in some aged mice in the R series, a more severe amyloidosis occurred with a higher incidence in the P series. There was a statistical significance between the incidence of amyloidosis and age, in both the P and R series. There were no differences in organ distribution and mode of amyloid deposition between the P and R series or between the sexes. In about 60% of the amyloid-positive cases in the 28 killed SAM and 7 mice in the R series, there were no signs of inflammation or neoplasm.The morphological features in SAM more closely resembled those seen in cases of murine spontaneous senile amyloidosis than the features seen in cases of experimentally induced amyloidosis. This model is expected to be a valuable tool with which to assess the relationship between amyloid deposition and the aging process or senescence, perhaps even cases of human senile amyloidosis. 相似文献
102.
Yewande E. Odeyemi ODene Lewis Julius Ngwa Kristen Dodd Richard F. Gillum Alem Mehari 《Journal of the National Medical Association》2019,111(1):94-100
Purpose
There is presently an ongoing debate on the relative merits of suggested criteria for spirometric airway obstruction. This study tests the null hypothesis that no superiority exists with the use of fixed ratio (FR) of forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC) < 0.7 versus less than lower limit predicted (LLN) criteria with or without FEV1 <80% predicted in regards to future mortality.Methods
In 1988–1994 the Third National Health and Nutrition Examination Survey (NHANES III) measured FEV1 and FVC with mortality follow-up data through December 31, 2011. For this survival analysis 7472 persons aged 40 and over with complete data formed the analytic sample.Results
There were a total of 3554 deaths. Weighted Cox proportional hazards regression revealed an increased hazard ratio in persons with both fixed ratio and lower limit of normal with a low FEV1 (1.79, p < 0.0001), in those with fixed ratio only with a low FEV1 (1.77, p < 0.0001), in those with abnormal fixed ratio only with a normal FEV1 (1.28, p < 0.0001) compared with persons with no airflow obstruction (reference group). These remained significant after adjusting for demographic variables and other confounding variables.Conclusions
The addition of FEV1 < 80% of predicted increased the prognostic power of the fixed ratio <0.7 and/or below the lower limit of predicted criteria for airway obstruction. 相似文献103.
We develop tidal-ventilation pulmonary gas-exchange equations that allow pulmonary shunt to have different values during expiration and inspiration, in accordance with lung collapse and recruitment during lung dysfunction (Am. J. Respir. Crit. Care Med. 158 (1998) 1636). Their solutions are tested against published animal data from intravascular oxygen tension and saturation sensors. These equations provide one explanation for (i) observed physiological phenomena, such as within-breath fluctuations in arterial oxygen saturation and blood-gas tension; and (ii) conventional (time averaged) blood-gas sample oxygen tensions. We suggest that tidal-ventilation models are needed to describe within-breath fluctuations in arterial oxygen saturation and blood-gas tension in acute respiratory distress syndrome (ARDS) subjects. Both the amplitude of these oxygen saturation and tension fluctuations, and the mean oxygen blood-gas values, are affected by physiological variables such as inspired oxygen concentration, lung volume, and the inspiratory:expiratory (I:E) ratio, as well as by changes in pulmonary shunt during the respiratory cycle. 相似文献
104.
产前血型IgG抗体水平的检测及其临床意义 总被引:3,自引:0,他引:3
目的探讨ABO血型不合孕妇的产前IgG抗体水平,了解IgG抗体效价异常在孕妇中所占比率及临床意义,为预防及诊治新生儿溶血病(HDN)采取有效的防治措施。方法用抗人球蛋白试管凝集法进行IgG抗A或抗B的ABO血型抗体效价检测。结果910例孕妇中,血清效价大于64者有108例,异常检出率为11.9%。IgG抗A效价大于64者有64例,检测率为11.8%;检测IgG抗B效价大于64者有54例,检测率为14.1%。讨论妊娠中IgG抗体效价与新生儿溶血密切相关,ABO血型不合的孕妇应及时作产前血清学的检测,可预防新生儿溶血病的发生及减轻胎儿受害的程度。 相似文献
105.
Na Ri Kang Yo Han Ahn Eujin Park Keum Hwa Lee Hee Sun Baek Seong Heon Kim Heeyeon Cho Min Hyun Cho Jae Il Shin Joo Hoon Lee Hae Il Cheong Hee Gyung Kang Young Seo Park Il-Soo Ha Duk-Soo Moon Kyoung Hee Han 《Journal of Korean medical science》2021,36(20)
BackgroundChronic kidney disease (CKD) has a negative impact on growth and development in children and is a risk factor for neurocognitive impairment; however, there is limited research on the cognitive function of children and adolescents with CKD. This study therefore aimed to investigate the mean intelligence and risk factors for low intelligence in children and adolescents with CKD.MethodsEighty-one patients with CKD under 18 years old were included in the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD). Participants completed either the Wechsler Intelligence Scale for Children (6–16 years), or Wechsler Adult Intelligence Scale (> 16 years).ResultsThe mean full-scale intelligence quotient (IQ) was 91 ± 19; 24.7% of participants scored a full-scale IQ below 80. Participants with a short stature (height Z scores < −1.88), failure to thrive (weight Z scores < −1.65), more severe CKD stage (≥ IIIb), longer duration of CKD (≥ 5 years), and those who were Medicare or Medicaid beneficiaries, had significantly lower mean full-scale IQs.ConclusionOn linear regression analysis, the association between the full-scale IQ, and longer duration of CKD and growth failure, remained significant after controlling for demographic and clinical variables. It is therefore necessary to investigate cognitive impairment in pediatric patients with CKD who exhibit growth failure or for a longer postmorbid period. It is believed that early interventions, such as kidney transplantation, will have a positive effect on IQ in children with CKD, as the disease negatively affects IQ due to poor glomerular filtration rate over time.Trial RegistrationClinicalTrials.gov Identifier: NCT02165878相似文献
106.
Mahmoud I. Abdel-Aziz Paul Brinkman Susanne J.H. Vijverberg Anne H. Neerincx John H. Riley Stewart Bates Simone Hashimoto Nazanin Zounemat Kermani Kian Fan Chung Ratko Djukanovic Sven-Erik Dahlén Ian M. Adcock Peter H. Howarth Peter J. Sterk Aletta D. Kraneveld Anke H. Maitland-van der Zee 《The Journal of allergy and clinical immunology》2021,147(1):123-134
107.
目的:研究汉语文化背景下的阿尔茨海默病患者的阅读能力和失读的特点。方法:正常老人、轻、中、重度AD各20名,性别、年龄和教育程度匹配。4组受试简明精神状态量表(MMSE)总分分别为27.7±2.2分、21.2±2.2分、15.2±2.3分和6.9±2.6分。汉字阅读包括22个记号字、17个音符字和17个义符字。结果:不管是记号字、音符字还是义符字,在正常老人组、轻度AD组和中度AD组之间两两比较没有显著差异(P>0.05),音符字和义符字在中度和重度AD组之间比较有显著差异(P<0.01)。“视觉性错读”在四组之间没有显著差异(P>0.05),表层失读出现在AD早期,并在AD晚期明显加重,好发于声符与其本字的发音不一致的义符字,不能用左侧忽视来解释。深层失读仅出现在AD晚期。组词现象是汉字深层失读的主要类型。结论:可以通过汉字阅读能力的评估判断早期痴呆被试的病前智力。汉字失读的类型与西方语言不同。 相似文献
108.
Marek’s disease virus (MDV), a highly cell-associated oncogenic chicken herpesvirus, causes Marek’s disease in domestic chickens. A unique phosphoprotein of MDV, pp38, has previously been associated with the maintenance of transformation in MDV-induced tumor cell lines. However, recently, the biological properties of a deletion mutant virus (rMd5Δpp38) revealed that pp38 is involved in early cytolytic infection in lymphocytes but not in the induction of tumors. Thus, pp38 is important for early cytolytic infection and not for transformation. The pp38 protein of the MDV serotype 1 vaccine strain CVI988/Rispens differs by one amino acid when compared to the pathogenic strains of MDV. Monoclonal antibody, H19, recognizes all serotype 1 MDV strains except CVI988/Rispens. Previous studies have also shown that the unique pp38 epitope in CVI988/Rispens induced high antibody response. In order to study the role of this epitope in the protective properties of CVI988/Rispens, we generated a mutant rMd5 virus in which the wild type pp38 gene has been substituted with that of CVI988/Rispens (rMd5/pp38CVI). The replication properties of rMd5/pp38CVI, both in vitro and in vivo, and tumor induction were examined. We found that the biological properties of rMd5/pp38CVI were similar to the wild type rMd5 virus with regards to in vivo replication, antibody response and tumor induction. This shows that the pp38 derived from CVI988/Rispens is not involved in protective properties as was previously suggested. 相似文献
109.
Rus V Zernetkina V Puliaev R Cudrici C Mathai S Via CS 《Clinical immunology (Orlando, Fla.)》2005,117(1):48-56
Increased expression of TRAIL in membrane-bound and soluble form in patients with systemic lupus erythematosus (SLE) has been previously reported. In this study, we characterized the upregulation of T-cell-associated and soluble TRAIL (sTRAIL) in vivo and the modulation of TRAIL expression and soluble protein release in vitro following T cell activation and IFNalpha exposure. The expression of membrane-bound TRAIL as determined by flow cytometry was higher on CD4(+) and CD8(+) T cells from lupus patients compared to controls, particularly on activated CD69(+)CD8(+) T cells. Similarly, sTRAIL levels determined by ELISA were significantly elevated in serum from patients with active SLE and correlated with levels of IFNalpha. In vitro, both T-cell-associated and sTRAIL were maximally induced by T cell activation plus IFNalpha in patients and controls. By Western blot analysis, sTRAIL was detected in sera in both the monomeric and multimeric, functional form. Both forms of TRAIL were functional in vitro as determined by Annexin V staining and (51)Cr release assay but the apoptotic activity of membrane TRAIL was 2.5-fold higher compared to that of sTRAIL. These results indicate that IFNalpha-induced enhancement of TRAIL expression and of TRAIL-mediated apoptosis may amplify the abnormal apoptotic process in SLE. 相似文献
110.
M. Weber C. v. Schacky R. Lorenz W. Meister J. Kotzur B. Reichart K. Theisen P. C. Weber 《Journal of molecular medicine (Berlin, Germany)》1984,62(10):458-464
Summary A prospective, randomized, doubleblind, placebo-controlled trial was conducted to evaluate the efficacy of Acetylsalicylic Acid (ASS) (100 mg/d, starting 24 h after operation) on vein graft patency. Sixty of 88 patients having undergone surgery entered the study; in 24 of 31 patients in the placebo group and 22 of 29 patients in the ASS-group angiography was performed 4 months postoperatively. There were no significant differences between the groups with respect to age, number of diseased vessels or previous myocardial infarctions. Mean number of grafts per patient was 2,2 (placebo) and 1,8 (ASS) for proximal anastomoses (p<0.10) and 3.4 (placebo) and 2.6 (ASS) for distal anastomoses (p<0.05). Graft occlusion rate for proximal anastomoses was less in the ASS-group, 10% (4/40), as compared with placebo 32% (17/53) (p<0.05). Graft occlusion rate for distal anastomoses was also less in the ASS group, 19% (11/57) as compared to 35% (28/81) in the placebo group (p<0.10). All grafts were patent in 16/22 patients in the ASS group but only in 9/24 in the placebo group (p<0.05). On designation of patients without postoperative angiograms but cardiovascular events as well as those with at least one graft occluded as failures, the incidence of the latter was 9/29 in the ASS group and 20/31 in the placebo group (p<0.05). Early postoperative bleeding was similar in both groups, no side effects of ASS were observed. In this trial with initiation of low — dose ASS therapy 24 h after operation, antiplatlet therapy reduced the graft occlusion rate significantly.
Teile dieser Studie wurden auf der 49. Tagung der Deutschen Gesellschaft für Herz- und Kreislaufforschung in Mannheim im April 1983 [32] und auf der 89. Tagung der Deutschen Gesellschaft für Innere Medizin, Wiesbaden, April 1983 [18] vorgetragen. Mit Unterstützung der Deutschen Forschungsgemeinschaft 相似文献