全文获取类型
收费全文 | 77312篇 |
免费 | 8614篇 |
国内免费 | 2107篇 |
专业分类
耳鼻咽喉 | 473篇 |
儿科学 | 1960篇 |
妇产科学 | 1663篇 |
基础医学 | 5228篇 |
口腔科学 | 1693篇 |
临床医学 | 8821篇 |
内科学 | 13278篇 |
皮肤病学 | 851篇 |
神经病学 | 4887篇 |
特种医学 | 1206篇 |
外国民族医学 | 7篇 |
外科学 | 7271篇 |
综合类 | 11837篇 |
现状与发展 | 8篇 |
一般理论 | 1篇 |
预防医学 | 14479篇 |
眼科学 | 1220篇 |
药学 | 5772篇 |
59篇 | |
中国医学 | 1999篇 |
肿瘤学 | 5320篇 |
出版年
2025年 | 26篇 |
2024年 | 1446篇 |
2023年 | 1886篇 |
2022年 | 3440篇 |
2021年 | 4359篇 |
2020年 | 4178篇 |
2019年 | 3038篇 |
2018年 | 2976篇 |
2017年 | 3060篇 |
2016年 | 3427篇 |
2015年 | 3108篇 |
2014年 | 6016篇 |
2013年 | 6341篇 |
2012年 | 5264篇 |
2011年 | 5383篇 |
2010年 | 4141篇 |
2009年 | 3727篇 |
2008年 | 3593篇 |
2007年 | 3452篇 |
2006年 | 2974篇 |
2005年 | 2526篇 |
2004年 | 2027篇 |
2003年 | 1723篇 |
2002年 | 1462篇 |
2001年 | 1256篇 |
2000年 | 1047篇 |
1999年 | 790篇 |
1998年 | 708篇 |
1997年 | 659篇 |
1996年 | 501篇 |
1995年 | 473篇 |
1994年 | 429篇 |
1993年 | 328篇 |
1992年 | 330篇 |
1991年 | 306篇 |
1990年 | 228篇 |
1989年 | 205篇 |
1988年 | 189篇 |
1987年 | 142篇 |
1986年 | 128篇 |
1985年 | 145篇 |
1984年 | 125篇 |
1983年 | 77篇 |
1982年 | 87篇 |
1981年 | 68篇 |
1980年 | 54篇 |
1979年 | 49篇 |
1978年 | 29篇 |
1977年 | 25篇 |
1976年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
1.
Jennifer M. Sasaki Russell Gregory A. Chinn Deenu Maharjan Yasmine Eichbaum Jeffrey W. Sall 《British journal of anaesthesia》2019,122(4):490-499
Background
The factors determining peak susceptibility of the developing brain to anaesthetics are unclear. It is unknown why postnatal day 7 (P7) male rats are more vulnerable to anaesthesia-induced memory deficits than littermate females. Given the precocious development of certain regions in the female brain during the neonatal critical period, we hypothesised that females are susceptible to anaesthetic brain injury at an earlier time point than previously tested.Methods
Female rats were exposed to isoflurane (Iso) 1 minimum alveolar concentration or sham anaesthesia at P4 or P7. Starting at P35, rats underwent a series of behavioural tasks to test their spatial and recognition memory. Cell death immediately after anaesthesia was quantified by Fluoro-Jade C staining in select brain regions, and developmental expression of the chloride transporters KCC2 and NKCC1 was analysed by immunoblotting in male and female rats at P4 and P7.Results
Female rats exposed to Iso at P4 displayed impaired spatial, object-place, -context, and social recognition memory, and increased cell death in the hippocampus and laterodorsal thalamus. Female rats exposed at P7 exhibited only decreased performance in object-context compared with control. The ratio of NKCC1/KCC2 expression in cerebral cortex was higher in P4 females than in P7 females, and similar to that in P7 males.Conclusions
Female rats exposed to Iso at P4 are sensitive to anaesthetic injury historically observed in P7 males. This is consistent with a comparably immature developmental state in P4 females and P7 males. The window of anaesthetic vulnerability correlates with sex-specific cortical expression of chloride transporters NKCC1 and KCC2. These findings suggest that both sex and developmental age play important roles in determining the outcome after early anaesthesia exposure. 相似文献2.
《Radiography》2022,28(3):746-750
IntroductionIn response to advice from The National Institute for Health and Care Excellence (1) to reduce hospital visits during COVID-19, standard headrests were introduced for head and neck radiotherapy within Northern Centre for Cancer Care (NCCC). The standard headrest requires one mould room appointment compared to 3 appointments with customised headrests.MethodsTwo groups of 10 patients treated between December 2019 and June 2020 were retrospectively analysed by 1 observer. Groups were stratified according to age, sex and tumour site. One group had customised headrest and the other had standard headrest. Five hundred and forty seven cone beam computed tomography images were reviewed. A 6 Degree of Freedom match was performed then chin, shoulder and spine position were assessed using dosimetrist drawn structures. Structures out of the tolerance were recorded. A chi-squared test was used for statistical analysis.ResultsThe out of tolerance chin position count recorded was 21 for customised headrest and 36 for standard headrest, p-value 0.046. The shoulder position count was 13 for customised headrest and 77 for standard headrest p-value <0.001. The spine position count was 3 for CHR and 21 for standard headrest, p-value <0.001. This means the headrests compared are not equivalent in terms of set up reproducibility. Overall the standard headrest group had 10 set-up re-scans and no set up re-scans were recorded in the customised headrest group.ConclusionFewer hospital visits with SHR reduce patient exposure to COVID-19. However, CHR provided a more reliable level of immobilisation in this study.Implications for practiceThe radiotherapy service will be reviewed in line with these findings. 相似文献
3.
Roberto Codella Lucio Della Guardia Ileana Terruzzi Anna Solini Franco Folli Elena Maria Varoni Antonio Carrassi Livio Luzi 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2021,31(8):2199-2209
While the beneficial impact of physical activity has been ascertained in a variety of pathological scenarios, including diabetes and low-grade systemic inflammation, its potential remains still putative for periodontal health. Periodontal disease has been associated with inflammatory systemic alterations, which share a common denominator with type 2 diabetes mellitus and cardiovascular disease. Physical exercise, along with nutritional counseling, is a cornerstone in the treatment and prevention of type 2 diabetes, also able to reduce the prevalence of periodontal disease and cardiovascular risk. In addition, considering the higher incidence of periodontitis in patients with type 2 diabetes compared to healthy controls, the fascinating research question would be whether physical activity could relieve the inflammatory pressure exerted by the combination of these two diseases. This multi-disciplinary viewpoint discusses available literature in order to argument the hypothesis of a “three–way relationship” linking diabetes, periodontitis, and physical activity. 相似文献
4.
5.
6.
Maryam Boumezrag Sormeh Harounzadeh Hamza Ijaz Angeline Johny Lorna Richards Yan Ma Maxine A. Le Saux Paige Kulie Caitlin Davis Andrew C. Meltzer 《The American journal of emergency medicine》2019,37(2):304-307
Study objectives
The primary objective of this study was to compare Emergency Department patients with first-time versus recurrent acute pancreatitis.Methods
This study was a retrospective chart review of patients with a diagnosis of acute pancreatitis who presented to a single academic urban emergency department from 2012 to 2016. Criteria for inclusion were clinical symptoms of pancreatitis, age greater than or equal to 18?years, ED diagnosis of acute pancreatitis, and an abdominal CT scan within 24?h of triage. Exclusion criteria were traumatic mechanism and pregnancy. Charts were reviewed by a minimum of two trained abstractors using structured data collection sheets and discrepancies were resolved by a third abstractor. Patients with first time acute pancreatitis versus recurrent acute pancreatitis were compared to determine differences in characteristics, management and disposition.Results
250 patients were included in the study. Of these, 165 patients had first-time acute pancreatitis and 85 patients had recurrent acute pancreatitis. Demographics, vital signs and initial lab values were the same in both groups. Patients with recurrent acute pancreatitis were more likely to have significant findings on CT (Modified CT Severity Index, 2.09 versus 1.43, p?<?0.05), more likely to require IV opiates (96% versus 75%, p?<?0.001) and less likely to need ICU admission (8% versus 19%, p?=?0.03).Conclusion
ED patients with recurrent acute pancreatitis demonstrated more significant findings on CT compared to patients with first-time acute pancreatitis but were less likely to require ICU admission. 相似文献7.
目的探讨龙葵当归三棱汤对卵巢癌患者的临床疗效及免疫指标及炎性因子的影响。方法选取2016年11月-2018年12月60例卵巢癌患者进行研究,随机分为试验组和对照组各30例,对照组采用单纯紫杉醇加顺铂化疗治疗,试验组在对照组的基础上进行龙葵当归三棱汤治疗,比较两组患者的总有效率、血清肿瘤标志物水平[CA125、癌胚抗原(CEA)]变化、以及Th1、Th2、Th1/Th2、调节性T淋巴细胞(Treg)及炎症因子[白细胞介素-2(IL-2)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10)]及干扰素(INF-γ)和不良反应。结果试验组的总有效率90.0%(27/30)明显高于对照组76.7%(23/30),差异具有统计学意义(P<0.05);试验组CA125、CEA、IL-2、IL-6、INF-γ均明显低于对照组,IL-10明显高于对照组,差异具有统计学意义(P<0.05);试验组的Th1、Th1/Th2均明显高于对照组(P<0.05),试验组的Th2、Treg明显低于对照组(P<0.05);试验组的不良反应率6.7%(2/30)明显低于对照组33.3%(10/30)(P<0.05)。结论龙葵当归三棱汤可以有效的改善卵巢癌的临床疗效,提高患者的免疫力,降低炎性反应和化疗的不良反应。 相似文献
8.
Shulin Wu Sharron X. Lin Gregory J. Wirth Min Lu Jian Lu Alexander O. Subtelny Zongwei Wang Douglas M. Dahl Aria F. Olumi Chin-Lee Wu 《Clinical genitourinary cancer》2019,17(1):e44-e52
Objective
To assess the impact of focality and location of positive surgical margins (PSM) on long-term outcomes after radical prostatectomy (RP) for prostate cancer (PCa), including biochemical recurrence (BCR), metastasis and overall mortality.Patients and Methods
From a total of 2796 cases of RP between 1993 and 2007 in our single hospital, 476 cases with PSMs were identified and included in this study. PSM location was categorized into apex, peripheral, and bladder neck. Survival was estimated using the Kaplan-Meier method. Cox proportional hazard regression models were used to analyze the impact of PSM focality and location status on oncologic survival.Results
Of these 476 cases with PSMs, 335 (70.4%) cases were with single focal (sF) PSMs and 141 (29.6%) cases were with multifocal (mF) PSMs. Furthermore, 406 (85.3%) cases were found to have single location (sL) PSMs, and 70 (14.7%) cases were with multilocation (mL) PSMs. The median follow-up was 12.9 years. mF-PSMs and mL-PSMs showed significant impact on increased BCR risk on univariate analysis, and mL-PSMs remained significant on multivariate analysis (P = .048). Furthermore, the combination of multifocality and multilocation showed added prognostic value on predicting BCR-free survival, but not on metastasis-free survival or overall survival.Conclusion
The presence of mF-PSMs and mL-PSMs, and especially the combination of both, demonstrated significant impact on BCR prognosis. Patients with apex sLsF-PSMs were less likely to have BCR when compared with all those with non-apex sLsF-PSMs. These results should be considered when evaluating patients for adjuvant therapy. 相似文献9.
Zihao Yu Di Kong Jiajun Peng Zehao Wang Yongjie Chen 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2021,31(1):52-59
Background and aimsFew studies have explored the association between malnutrition, defined by the Geriatric Nutritional Risk Index (GNRI), and all-cause mortality, particularly in the Chinese population. This study aimed to investigate the association between the GNRI and all-cause mortality in the elderly population.Methods and resultsParticipants aged ≥60 years were eligible for this study and were divided into three groups by the GNRI: An adequate nutrition group, participants with a GNRI ≥98; mild malnutrition group, participants with a GNRI ≥82 but <98; and a severe malnutrition group, participants with a GNRI <82. The results implied that there was a positive association between severe malnutrition and all-cause mortality in the total population (hazard ratio (HR): 2.591 and 95% confidence interval (CI): 1.729–3.884), male subjects (HR: 2.903 and 95% CI: 1.718–4.906), and female subjects (HR: 2.081 and 95% CI: 1.071–4.046). Similar associations between severe malnutrition and all-cause mortality were observed in both the 60–69 and 70–79 years age groups (HR: 2.863 and 2.600, 95% CI: 1.444–5.678 and 1.394–4.849, respectively). However, no significant association was observed between mild malnutrition and all-cause mortality.ConclusionsSevere malnutrition could increase all-cause mortality in the 60- to 79-year-old population. However, there was no association of mild malnutrition with all-cause mortality. 相似文献
10.
Grete Moth Morten B. Christensen Helle Collatz Christensen Anders H. Carlsen Ingunn S. Riddervold Linda Huibers 《Scandinavian journal of primary health care》2020,38(3):272-280
Abstract