全文获取类型
收费全文 | 6969篇 |
免费 | 331篇 |
国内免费 | 74篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 128篇 |
妇产科学 | 259篇 |
基础医学 | 530篇 |
口腔科学 | 132篇 |
临床医学 | 609篇 |
内科学 | 1926篇 |
皮肤病学 | 138篇 |
神经病学 | 366篇 |
特种医学 | 289篇 |
外科学 | 1397篇 |
综合类 | 26篇 |
预防医学 | 334篇 |
眼科学 | 147篇 |
药学 | 310篇 |
中国医学 | 3篇 |
肿瘤学 | 667篇 |
出版年
2024年 | 3篇 |
2023年 | 49篇 |
2022年 | 134篇 |
2021年 | 244篇 |
2020年 | 144篇 |
2019年 | 204篇 |
2018年 | 211篇 |
2017年 | 152篇 |
2016年 | 174篇 |
2015年 | 170篇 |
2014年 | 306篇 |
2013年 | 339篇 |
2012年 | 594篇 |
2011年 | 609篇 |
2010年 | 369篇 |
2009年 | 333篇 |
2008年 | 577篇 |
2007年 | 593篇 |
2006年 | 481篇 |
2005年 | 407篇 |
2004年 | 352篇 |
2003年 | 317篇 |
2002年 | 260篇 |
2001年 | 38篇 |
2000年 | 19篇 |
1999年 | 36篇 |
1998年 | 54篇 |
1997年 | 27篇 |
1996年 | 30篇 |
1995年 | 23篇 |
1994年 | 18篇 |
1993年 | 12篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1976年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有7374条查询结果,搜索用时 15 毫秒
41.
Dimitrios I. Athanasiadis Sara Monfared Hamed Asadi Cameron L. Colgate Denny Yu Dimitrios Stefanidis 《Surgery》2021,169(3):496-501
BackgroundWork-related musculoskeletal injuries have been increasingly recognized to affect surgeons. It is unknown whether such injuries also affect surgical trainees. The purpose of this study was to assess the ergonomic risk of surgical trainees as compared with that of experienced surgeons.MethodsErgonomic data were recorded from 9 surgeons and 11 trainees. Biomechanical loads during surgery were assessed using motion tracking sensors and electromyography sensors. Demanding and static positions of the trunk, neck, right/left shoulder, as well as activity from the deltoid and trapezius muscles bilaterally were recorded. In addition, participants reported their perceived discomfort on validated questionnaires.ResultsA total of 87 laparoscopic general surgery cases (48 attendings and 39 trainees) were observed. Both trainees and attendings spent a similarly high percentage of each case in static (>60%) and demanding positions (>5%). Even though residents reported overall more discomfort, all participants shared similar ergonomic risk with the exception of trainees’ trunk being more static (odds ratio: –11.42, P = .006).ConclusionSurgeons are prone to ergonomic risk. Trainees are exposed to similar postural ergonomic risk as surgeons but report more discomfort and, given that musculoskeletal injuries are cumulative over time, the focus should be on interventions to reduce ergonomic risk in the operating room. 相似文献
42.
Dimitrios I. Athanasiadis Edward Hernandez William Hilgendorf Alexandra Roper Marisa Embry Don Selzer Dimitrios Stefanidis 《Surgery for obesity and related diseases》2021,17(4):756-764
BackgroundThe global coronavirus disease 2019 (COVID-19) pandemic is wreaking havoc on society. Bariatric patients are more prone to severe infection due to their high body mass index (BMI) and are more vulnerable to the effects of isolation, such as depression or disruption of their health habits.ObjectivesTo quantify the impact of self-quarantine on bariatric patients and self-quarantine’s relationship with weight gain.SettingAcademic hospital, United States.MethodsA 30-item survey examining several known contributors to weight regain was distributed among the postoperative bariatric patients of our clinic. Changes in eating habits, exercise, depression, social support, loneliness, and anxiety were studied, among others.ResultsA total of 208 patients completed the survey (29.3% response rate). A large percentage of patients reported increases in their depression (44.2%), loneliness (36.2%), nervousness (54.7%), snacking (62.6%), loss of control when eating (48.2%), and binge eating (19.5%) and decreases in their social support (23.2%), healthy food eating (45.5%), and activity (55.2%). Difficulty in accessing vitamins was reported by 13%. Patients more than 18 months out of surgery regained more than 2 kg during an average of 47 days. Risk factors for weight regain were found to be loss of control when eating, increases in snacking and binge eating, reduced consumption of healthy food, and reduced physical activity.ConclusionBariatric patients are negatively affected by the COVID-19 pandemic and subsequent social isolation on many levels. This patient population is vulnerable to crisis situations; thus, additional intervention is needed to address behaviors that lead to weight regain. 相似文献
43.
Dimitrios Moris Brian I. Shaw Cecilia Ong Ashton Connor Mariya L. Samoylova Samuel J. Kesseli Nader Abraham Jared Gloria Robin Schmitz Zachary W. Fitch Bryan M. Clary Andrew S. Barbas 《肝胆外科与营养》2021,10(3):315
BackgroundSelection of the optimal treatment modality for primary liver cancers remains complex, balancing patient condition, liver function, and extent of disease. In individuals with preserved liver function, liver resection remains the primary approach for treatment with curative intent but may be associated with significant mortality. The purpose of this study was to establish a simple scoring system based on Model for End-stage Liver Disease (MELD) and extent of resection to guide risk assessment for liver resections.MethodsThe 2005–2015 NSQIP database was queried for patients undergoing liver resection for primary liver malignancy. We first developed a model that incorporated the extent of resection (1 point for major hepatectomy) and a MELD-Na score category of low (MELD-Na =6, 1 point), medium (MELD-Na =7–10, 2 points) or high (MELD-Na >10, 3 points) with a score range of 1–4, called the Hepatic Resection Risk Score (HeRS). We tested the predictive value of this model on the dataset using logistic regression. We next developed an optimal multivariable model using backwards sequential selection of variables under logistic regression. We performed K-fold cross validation on both models. Receiver operating characteristics were plotted and the optimal sensitivity and specificity for each model were calculated to obtain positive and negative predictive values.ResultsA total of 4,510 patients were included. HeRS was associated with increased odds of 30-day mortality [HeRS =2: OR =3.23 (1.16–8.99), P=0.025; HeRS =3: OR =6.54 (2.39–17.90), P<0.001; HeRS =4: OR =13.69 (4.90–38.22), P<0.001]. The AUC for this model was 0.66. The AUC for the optimal multivariable model was higher at 0.76. Under K-fold cross validation, the positive predictive value (PPV) and negative predictive value (NPV) of these two models were similar at PPV =6.4% and NPV =97.7% for the HeRS only model and PPV =8.4% and NPV =98.1% for the optimal multivariable model.ConclusionsThe HeRS offers a simple heuristic for estimating 30-day mortality after resection of primary liver malignancy. More complicated models offer better performance but at the expense of being more difficult to integrate into clinical practice. 相似文献
44.
Pyrgaki Konstantina Argyraki Ariadne Kelepertzis Efstratios Botsou Fotini Megremi Ifigeneia Karavoltsos Sotirios Dassenakis Emmanuel Mpouras Thanasis Dermatas Dimitrios 《Bulletin of environmental contamination and toxicology》2021,106(3):446-452
Bulletin of Environmental Contamination and Toxicology - The holistic approach of Driver-Pressure-State-Impact-Response (DPSIR) methodology was applied to selected Cr(VI) impacted groundwater... 相似文献
45.
Zoi Tsimtsiou Ioanna Tsiligianni Anastasia Papaioannou Dimitrios Gougourelas Konstantinos Kolokas Vasileios Gkizlis Emmanuil Chatzimanolis Philippe-Richard J. Domeyer 《Health & social care in the community》2021,29(3):818-828
Despite the unequivocal value of vaccination in reducing the global burden of infectious diseases, the anti-vaccination movement thrives. The vast majority of the existing validated tools explore attitudes regarding vaccination in children. The aim of our study was to develop and validate a scale assessing attitudes towards adult immunisation. This national cross-sectional study included adult healthcare users who visited 23 Greek Primary Healthcare Units. The development of the scale was the result of literature review, semi-structured interviews and pilot testing of its preliminary versions. The initial version contained 15 items measuring respondents’ attitudes on a 6-point Likert scale. The sample was randomly split into two halves. Exploratory factor analysis, performed in the first sample, was used for the creation of multi-item scales; confirmatory factor analysis was used in the second sample to assess goodness of fit. Moreover, concurrent validity, internal consistency reliability, test–retest reliability and ceiling and floor effects were explored. The total sample consisted of 1,571 individuals. Overall ‘Cronbach's alpha’ (0.821) indicated good internal consistency. The initial exploratory factor analysis resulted in a three-factor model. The subsequent confirmatory factor analysis indicated that an 11-item version of the scale provided the best fit of the model to the data (RMSEA = 0.050, SRMR = 0.053, TLI = 0.937, CFI = 0.955, AIC = 24,999.949). All subscales (‘value of adult vaccination’, ‘safety concerns’ and ‘perceived barriers’) demonstrated strong concurrent associations with participants’ attitudes and behaviour regarding vaccination (p < .001). No ceiling or floor effects were noted for any of the subscales (0.13%, 2.61% and 0.51%; 0.13%, 0.57% and 0.45% respectively). The 11-item ATAVAC scale proved to be a reliable and valid tool, suitable for assessing attitudes towards adult vaccination. 相似文献
46.
The a- and b-wave latencies as a prognostic indicator of neovascularisation in central retinal vein occlusion 总被引:1,自引:0,他引:1
Moschos M Brouzas D Moschou M Theodossiadis G 《Documenta ophthalmologica. Advances in ophthalmology》1999,99(2):123-133
To evaluate the prognostic value of ERG in cases of central retinal vein occlusion (CRVO) regarding the development of neovascularisation
(NV), we studied 20 patients with unilateral CRVO. Half of them were allocated in the perfused group and the other 10 finally
developed NV and were allocated in the non-perfused group. Flash ERG was recorded from all patients. Our findings suggest
that b-wave latency is the most reliable parameter in predicting NV, followed by the a-wave latency. The b/a wave amplitude of ERG ratio does not seem to be suitable for clinical use.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
47.
48.
Maternal risk of breast cancer following multiple births: a nationwide study in Sweden 总被引:2,自引:0,他引:2
Mats Lambe Chung-cheng Hsieh Shirng-wern Tsaih Anders Ekbom Hans-Olov Adami Dimitrios Trichopoulos 《Cancer causes & control : CCC》1996,7(5):533-538
The association between multiple births and subsequent maternal breast cancer risk was explored in a nested case-control study in Sweden encompassing 19,368 parous women with breast cancer diagnosed up to age 65 years, and 100,459 parous controls. Among cases and controls, there were 329 and 2,031 women, respectively, with a history of at least one live multiple birth. Compared with singleton mothers, breast cancer risk was 12 percent lower (odds ratio=0.088, 95 percent confidence interval=0.78–0.99) in women who had had a multiple birth. After stratification for age at diagnosis, evidence of a significant inverse association was found only in women aged 54 years or younger. Birth order of the multiple pregnancy had no apparent risk-modifying effect. Age at earliest multiple birth was unrelated to breast cancer risk. The inverse association between twinning and breast cancer risk may reflect protective physiological features of twin pregnancies. Further research is needed to investigate the role, if any, of in creased levels of steroid hormone-binding globulins in mothers of twins and the proposed inhibitory effects of human chorionic gonadotropin and -fetoprotein, both of which are increased during multiple gestations, on breast carcinogenesis. Breast feeding patterns in mothers of twins also may modify their risk of developing breast cancer.Ambors are with the Department of Cancer Epidemiology (Drs Lambe Ekbom, Adami) and Department of Social Medicine (Lambe), University Hospital, Uppsala, Sweden: Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA (Drs Hsieb, Tsilib, Adami, Ekbom, Trichopoulos); UMASS Cancer Center, Worcester, MA, USA (Dr Hsieb). Address correspondece to Dr Lambe, Department of Cancer Epidemiology, University Hospital, S-751 85 Uppsala, Sweden. This project is funded by grants from the Swedish Cencer Societv. the Swedish Societv of Medicine. and the Wahlmarks Fund at Uppsala City Council. 相似文献
49.
Keiko Yamanaka Nikolaos V. Sofikitis Ikuo Miyagawa Yasuhisa Yamamoto Toshiko Toda Spyros Antypas Dimitrios Dimitriadis Manami Takenaka Koji Taniguchi Katsuhiko Takahashi Sanae Tsukamoto Hiroshi Kawamura Martin Neil 《Journal of assisted reproduction and genetics》1997,14(1):55-62
Purpose: Our objective was to apply ooplasmic round spermatid nuclear injections for the treatment of nonobstructive azoospermia.
Materials: Participants were nine azoospermic men who had previously undergone diagnostic testicular biopsy. Spermatogenetic arrest
was diagnosed at the round spermatid stage (n=6) or primary spermatocyte stage (n=3). A second (therapeutic) testicular biopsy
was performed and round spermatid nuclei were recovered from all the participants.
Results: Forty-nine mature oocytes were successfully injected with nuclei and then cultured for 72 hr. Twenty-four embryos were transferred
to nine women. No pregnancy was achieved.
Conclusions: Round spermatids can be recovered from therapeutic testicular biopsy material of men negative for round spermatids in previous
routine diagnostic testicular biopsy specimens. Round spermatid nuclear injections may play a role in the treatment of nonobstructive
azoospermia. 相似文献
50.
Eleni Petridou Freda E. Alexander Dimitrios Trichopoulos Katharine Revinthi Nick Dessypris Naomi Wray Stavros Haidas Dimitrios Koliouskas Helen Kosmidis Fani Piperopoulou Fotini Tzortzatou 《Cancer causes & control : CCC》1997,8(2):239-245
A total of 872 children aged up to 14 years, who were diagnosed withleukemia in Greece during the decade 1980-89, were allocated by place ofresidence to the 601 administrative districts of the country. Evaluation ofspatial clustering was done using the Potthoff-Whittinghill method, whichvalidly assesses heterogeneity of leukemia risk among districts with variableexpected numbers of cases. There was highly significant evidence for spatialclustering occurring particularly among children living in urban and, to alesser extent, semi-urban areas. The evidence was stronger for childrenyounger than 10 years old, applied also to children in different five-yearage groups, and persisted when cases of acute lymphoblastic leukemia wereanalyzed separately. These findings provide support to the hypothesis thatlocalized environmental exposures could contribute to the etiology ofchildhood leukemia, but they cannot distinguish between exposures of physicalor chemical nature, nor can they exclude socially conditioned patterns ofexposure to infectious agents. 相似文献