全文获取类型
收费全文 | 26698篇 |
免费 | 1533篇 |
国内免费 | 630篇 |
专业分类
耳鼻咽喉 | 218篇 |
儿科学 | 460篇 |
妇产科学 | 420篇 |
基础医学 | 3170篇 |
口腔科学 | 217篇 |
临床医学 | 3013篇 |
内科学 | 3199篇 |
皮肤病学 | 121篇 |
神经病学 | 1966篇 |
特种医学 | 1404篇 |
外国民族医学 | 1篇 |
外科学 | 2764篇 |
综合类 | 3824篇 |
一般理论 | 1篇 |
预防医学 | 2203篇 |
眼科学 | 498篇 |
药学 | 3521篇 |
15篇 | |
中国医学 | 691篇 |
肿瘤学 | 1155篇 |
出版年
2024年 | 55篇 |
2023年 | 292篇 |
2022年 | 632篇 |
2021年 | 811篇 |
2020年 | 720篇 |
2019年 | 592篇 |
2018年 | 630篇 |
2017年 | 768篇 |
2016年 | 823篇 |
2015年 | 846篇 |
2014年 | 1655篇 |
2013年 | 1823篇 |
2012年 | 1726篇 |
2011年 | 1688篇 |
2010年 | 1339篇 |
2009年 | 1267篇 |
2008年 | 1255篇 |
2007年 | 1224篇 |
2006年 | 1076篇 |
2005年 | 949篇 |
2004年 | 804篇 |
2003年 | 704篇 |
2002年 | 585篇 |
2001年 | 520篇 |
2000年 | 461篇 |
1999年 | 470篇 |
1998年 | 418篇 |
1997年 | 397篇 |
1996年 | 375篇 |
1995年 | 361篇 |
1994年 | 293篇 |
1993年 | 238篇 |
1992年 | 237篇 |
1991年 | 211篇 |
1990年 | 182篇 |
1989年 | 196篇 |
1988年 | 182篇 |
1987年 | 197篇 |
1986年 | 189篇 |
1985年 | 264篇 |
1984年 | 231篇 |
1983年 | 163篇 |
1982年 | 196篇 |
1981年 | 182篇 |
1980年 | 175篇 |
1979年 | 111篇 |
1978年 | 97篇 |
1977年 | 74篇 |
1976年 | 65篇 |
1975年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
《Cancer radiothérapie》2022,26(4):611-615
In order to provide more convenient irradiation regimens for patient comfort, radiation facility organization and health expenses, new hypofractionated protocols have been evaluated. Moderately (dose/fraction: 2.3 to 3 Gy), then ultra (dose/fraction: 5.2 to 6.1 Gy) hypofractionated irradiations were first validated. The current question is: is it possible to go forward using extreme hypofractionated regimens (EHR) based on 1 to 3 fractions. Different irradiation techniques are under investigation. However, brachytherapy remains the smartest way to deliver a high dose in a small volume. We report prospective and retrospective study results which evaluated EHR for breast and prostate brachytherapy. While oncological outcome and toxicity profile appear extremely encouraging for low-risk breast cancer after a 1 to 4 fractions (6.25 to 20 Gy/fraction), the use of a single fraction of 19 to 23 Gy appears debatable for prostate cancer. Brachytherapy represents an emblematic example of EHR but longer follow-up and more mature results are awaited in order to specify the right indications and refine the EQD2 calculation method including new biological and technical factors. 相似文献
2.
3.
4.
《Clinical neurophysiology》2021,132(9):2003-2011
ObjectiveA large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS.MethodsA total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis.ResultsPatients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively).ConclusionsThe HFO amplitude in ALS is increased, but does not predict survival.SignificanceThe enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons. 相似文献
5.
6.
随着社会的发展,人类生活方式的改变,高血压病越来越高发,具有低龄化趋势,代谢综合征常伴随发生,此种情况下的高血压往往是以舒张压升高为主,临床表现常与“亚健康”状态混淆,未能引起患者甚至部分医生的重视,然而事实上越来越多的科学研究证实舒张压高之危害十分明显,不容忽视。尽管现代医学对舒张压高的病因及病理机制有明确的阐述,但是暂时没有特效的药物。李延教授在治疗高血压病方面有着丰富的临床经验,临床中运用泽泻汤合温胆汤加减治疗舒张压高之眩晕,切中病机,加减灵活,屡有良效。文中从中医角度阐述舒张压高的病因病机,介绍李师辨病辨证思路,组方用药特点,附三则典型验案,另加个人心得体会,以期为舒张压高的有效治疗提供思路。 相似文献
7.
Unconditional Positivity-Preserving and Energy Stable Schemes for a Reduced Poisson-Nernst-Planck System 下载免费PDF全文
Hailiang Liu & Wumaier Maimaitiyiming 《Communications In Computational Physics》2020,27(5):1505-1529
The Poisson-Nernst-Planck (PNP) system is a widely accepted model for
simulation of ionic channels. In this paper, we design, analyze, and numerically validate a second order unconditional positivity-preserving scheme for solving a reduced
PNP system, which can well approximate the three dimensional ion channel problem.
Positivity of numerical solutions is proven to hold true independent of the size of time
steps and the choice of the Poisson solver. The scheme is easy to implement without
resorting to any iteration method. Several numerical examples further confirm the
positivity-preserving property, and demonstrate the accuracy, efficiency, and robustness of the proposed scheme, as well as the fast approach to steady states. 相似文献
8.
《Diagnostic and interventional imaging》2020,101(9):555-564
PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%. 相似文献
9.
10.
Dominique Trudel Luminita-Mihaela Avarvarei Michèle Orain Stéphane Turcotte Marie Plante Jean Grégoire Reinhild Kappelhoff David P. Labbé Dimcho Bachvarov Bernard Têtu Christopher M. Overall Isabelle Bairati 《Pathology, research and practice》2019,215(6):152369
Ovarian carcinoma is one of the most lethal malignancies, but only very few prognostic biomarkers are known. The degradome, comprising proteases, protease non-proteolytic homologues and inhibitors, have been involved in the prognosis of many cancer types, including ovarian carcinoma. The prognostic significance of the whole degradome family has not been specifically studied in high-grade serous ovarian cancer. A targeted DNA microarray known as the CLIP-CHIP microarray was used to identify potential prognostic factors in ten high-grade serous ovarian cancer women who had early recurrence (<1.6 years) or late/no recurrence after first line surgery and chemotherapy. In women with early recurrence, we identified seven upregulated genes (TMPRSS4, MASP1/3, SPC18, PSMB1, IGFBP2, CFI – encoding Complement Factor I – and MMP9) and one down-regulated gene (ADAM-10). Using immunohistochemistry, we evaluated the prognostic effect of these 8 candidate genes in an independent cohort of 112 high-grade serous ovarian cancer women. Outcomes were progression, defined according to CA-125 criteria, and death. Multivariate Cox proportional hazard regression models were done to estimate the associations between each protein and each outcome. High ADAM-10 expression (intensity of 2–3) was associated with a lower risk of progression (adjusted hazard ratio (HR): 0.51; 95% confidence interval (CI): 0.29-0.87). High complement factor I expression (intensity 2–3) was associated with a higher risk of progression (adjusted HR: 2.30, 95% CI: 1.17–4.53) and death (adjusted HR: 3.42; 95% CI: 1.72–6.79). Overall, we identified the prognostic value of two proteases, ADAM-10 and complement factor I, for high-grade serous ovarian cancer which could have clinical significance. 相似文献