全文获取类型
收费全文 | 15247篇 |
免费 | 1512篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 265篇 |
儿科学 | 601篇 |
妇产科学 | 323篇 |
基础医学 | 1646篇 |
口腔科学 | 1050篇 |
临床医学 | 1412篇 |
内科学 | 3461篇 |
皮肤病学 | 459篇 |
神经病学 | 855篇 |
特种医学 | 416篇 |
外科学 | 2504篇 |
综合类 | 551篇 |
一般理论 | 8篇 |
预防医学 | 899篇 |
眼科学 | 407篇 |
药学 | 968篇 |
中国医学 | 78篇 |
肿瘤学 | 925篇 |
出版年
2024年 | 10篇 |
2023年 | 170篇 |
2022年 | 525篇 |
2021年 | 823篇 |
2020年 | 503篇 |
2019年 | 718篇 |
2018年 | 804篇 |
2017年 | 595篇 |
2016年 | 697篇 |
2015年 | 686篇 |
2014年 | 824篇 |
2013年 | 985篇 |
2012年 | 1083篇 |
2011年 | 1172篇 |
2010年 | 743篇 |
2009年 | 560篇 |
2008年 | 752篇 |
2007年 | 728篇 |
2006年 | 678篇 |
2005年 | 669篇 |
2004年 | 584篇 |
2003年 | 503篇 |
2002年 | 425篇 |
2001年 | 213篇 |
2000年 | 191篇 |
1999年 | 160篇 |
1998年 | 88篇 |
1997年 | 63篇 |
1996年 | 65篇 |
1995年 | 52篇 |
1994年 | 41篇 |
1993年 | 36篇 |
1992年 | 56篇 |
1991年 | 43篇 |
1990年 | 44篇 |
1989年 | 44篇 |
1988年 | 57篇 |
1987年 | 61篇 |
1986年 | 47篇 |
1985年 | 50篇 |
1984年 | 38篇 |
1983年 | 23篇 |
1982年 | 13篇 |
1981年 | 19篇 |
1980年 | 13篇 |
1979年 | 19篇 |
1977年 | 17篇 |
1975年 | 10篇 |
1969年 | 12篇 |
1966年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Mohammed Al Ani George Garas James Hollingshead Drostan Cheetham Thanos Athanasiou Vanash Patel 《Medical principles and practice》2022,31(4):342
The UK government had intended to introduce a comprehensive Electronic Health Record (EHR) system in England by 2020. These EHRs would run across primary, secondary, and social care, linking data in a single digital platform. The objectives of this systematic review were to identify studies that compare EHR in terms of direct comparison between systems and to evaluate them using System and Software Quality Requirements and Evaluation (SQuaRE) ISO/IEC 25010. A systematic review was performed by searching Embase and Ovid MEDLINE databases between 1974 and April 2021. All original studies that appraised EHR systems and their providers were included. The main outcome measures were EHR system comparison and the eight characteristics of SQuaRE: functional suitability, performance efficiency, compatibility, usability, reliability, security, maintainability, and portability. A total of 724 studies were identified using the search criteria. After a review of titles and abstracts, this was filtered down to 40 studies as per the exclusion and inclusion criteria set out in our study. Seven studies compared more than one EHR. The following number of studies looked at the various aspects of the SQuaRE, respectively − 19 studies: functional suitability, performance efficiency: 18 studies, compatibility: 12 studies, usability: 25 studies, reliability: 6 studies, security: 2 studies, maintainability: 16 studies, portability: 13 studies. Epic was the most studied EHR system and one of the most implemented systems in the US market and one of the top ten in the UK. It is difficult to assess which is the most advantageous EHR system when they are assessed by SQuaRE''s 8 characteristics for software evaluation. 相似文献
102.
Luthfia Pratiwi Diana Rakhmawaty Eddy Jamaludin Al Anshori Asep Harja Tatang Wahyudi Agus Surya Mulyawan Euis Julaeha 《RSC advances》2022,12(47):30682
A functional fabric immobilized by the microcapsules of C. aurantifolia lime essential oil (LO) was prepared and characterized. A varied amount of CaCl2 crosslinker was optimized to coacervate LO using alginate–gelatin biopolymers and Tween 80 emulsifier. A further evaluation of the immobilized LO microcapsules for the antibacterial effect against both Gram-positive and Gram-negative bacteria was conducted. The optimized alginate/gelatin-based microcapsules were effectively crosslinked by 15% CaCl2 with an yield, oil content (OC), and encapsulation efficiency (EE) of 39.91 ± 3.10%, 78.33 ± 7.53%, and 90.27 ± 5.84%, respectively. A spherical shape of LO microcapsules was homogeneously found with an average particle size of 1.394 μm. A first-order kinetics mechanism for the release of LO out of the microcapsules was modeled by Avrami''s kinetic equation (k = 1.60 ± 3.68 × 10−5 s−1). The LO microcapsules demonstrated good thermal stability up to 100 °C and maintained 51.07% OC and 43.56% EE at ambient temperature for three weeks. Using a pad dry method and citric acid binder, LO microcapsules were successfully immobilized on a cloth with a % add on 30.60 ± 1.80%. The LO microcapsules and the immobilized one exhibited a moderate ZoI of bacterial growth for Gram-positive S. aureus and S. epidermidis as well as Gram-negative E. coli and K. pneumonia. Further washing test toward the functional fabric showed that the LO microcapsules incorporated into the fabric were resistant to five cycles of normal washing with a mass reduction of 22.01 ± 1.69%.A functional fabric immobilized by the microcapsules of C. aurantifolia lime essential oil (LO) was prepared and characterized. 相似文献
103.
Athar Khalil Khalil Al Handawi Zeina Mohsen Afif Abdel Nour Rita Feghali Ibrahim Chamseddine Michael Kokkolaras 《Viruses》2022,14(7)
The rapid spread of the coronavirus disease COVID-19 has imposed clinical and financial burdens on hospitals and governments attempting to provide patients with medical care and implement disease-controlling policies. The transmissibility of the disease was shown to be correlated with the patient’s viral load, which can be measured during testing using the cycle threshold (Ct). Previous models have utilized Ct to forecast the trajectory of the spread, which can provide valuable information to better allocate resources and change policies. However, these models combined other variables specific to medical institutions or came in the form of compartmental models that rely on epidemiological assumptions, all of which could impose prediction uncertainties. In this study, we overcome these limitations using data-driven modeling that utilizes Ct and previous number of cases, two institution-independent variables. We collected three groups of patients (n = 6296, n = 3228, and n = 12,096) from different time periods to train, validate, and independently validate the models. We used three machine learning algorithms and three deep learning algorithms that can model the temporal dynamic behavior of the number of cases. The endpoint was 7-week forward number of cases, and the prediction was evaluated using mean square error (MSE). The sequence-to-sequence model showed the best prediction during validation (MSE = 0.025), while polynomial regression (OLS) and support vector machine regression (SVR) had better performance during independent validation (MSE = 0.1596, and MSE = 0.16754, respectively), which exhibited better generalizability of the latter. The OLS and SVR models were used on a dataset from an external institution and showed promise in predicting COVID-19 incidences across institutions. These models may support clinical and logistic decision-making after prospective validation. 相似文献
104.
Mohammed S. Alqahtani Mohamed Abbas Mohammed Abdulmuqeet Abdullah S. Alqahtani Mohammad Y. Alshahrani Abdullah Alsabaani Murugan Ramalingam 《Materials》2022,15(14)
The COVID-19 pandemic has the tendency to affect various organizational paradigm alterations, which civilization hasyet to fully comprehend. Personal to professional, individual to corporate, and across most industries, the spectrum of transformations is vast. Economically, the globe has never been more intertwined, and it has never been subjected to such widespread disruption. While many people have felt and acknowledged the pandemic’s short-term repercussions, the resultant paradigm alterations will certainly have long-term consequences with an unknown range and severity. This review paper aims at acknowledging various approaches for the prevention, detection, and diagnosis of the SARS-CoV-2 virus using nanomaterials as a base material. A nanostructure is a material classification based on dimensionality, in proportion to the characteristic diameter and surface area. Nanoparticles, quantum dots, nanowires (NW), carbon nanotubes (CNT), thin films, and nanocomposites are some examples of various dimensions, each acting as a single unit, in terms of transport capacities. Top-down and bottom-up techniques are used to fabricate nanomaterials. The large surface-to-volume ratio of nanomaterials allows one to create extremely sensitive charge or field sensors (electrical sensors, chemical sensors, explosives detection, optical sensors, and gas sensing applications). Nanowires have potential applications in information and communication technologies, low-energy lightning, and medical sensors. Carbon nanotubes have the best environmental stability, electrical characteristics, and surface-to-volume ratio of any nanomaterial, making them ideal for bio-sensing applications. Traditional commercially available techniques have focused on clinical manifestations, as well as molecular and serological detection equipment that can identify the SARS-CoV-2 virus. Scientists are expressing a lot of interest in developing a portable and easy-to-use COVID-19 detection tool. Several unique methodologies and approaches are being investigated as feasible advanced systems capable of meeting the demands. This review article attempts to emphasize the pandemic’s aftereffects, utilising the notion of the bullwhip phenomenon’s short-term and long-term effects, and it specifies the use of nanomaterials and nanosensors for detection, prevention, diagnosis, and therapy in connection to the SARS-CoV-2. 相似文献
105.
106.
107.
The authors studied 1,681 consecutive patients who attended their ophthalmic outpatient clinics over a period of 12 months to determine the patients' visual acuity status and the causes of any visual loss. Using the World Health Organization criteria for definition of visual acuity status, 1004 (59.7%) patients had normal vision. Four hundred and thirty-one (25.6%) patients had low vision or visual impairment and 246 (14.6%) patients were blind. Twenty-eight (1.9%) patients had no light perception in both eyes. Cataract, both in isolation and co-existing with other ocular pathology, was the major cause of both low vision and blindness (58.5% and 81.7%, respectively). A concerted attack on cataract alone will markedly reduce blindness and low vision in this region. 相似文献
108.
Polyphenols and Their Role in Obesity Management: A Systematic Review of Randomized Clinical Trials 下载免费PDF全文
Polyphenols have been suggested to reduce body weight and modify body composition through different mechanisms. These effects have been extensively studied in animals and in vitro and to a lesser extent in humans. The aim of this review is to consider the association between polyphenols and body weight status by focusing on human intervention studies. We conducted a systematic literature search in MEDLINE (via EBSCOhost), ProQuest CENTRAL, and Cochrane CENTRAL without time restrictions. Randomized controlled trials assessing the effect of polyphenols on weight and/or body composition in the overweight and/or obese population were included. Nineteen studies met our inclusion criteria. Results suggest that further research is required before supporting a potential role of polyphenols in reducing weight in overweight and obese individuals (nine studies showed a significant decrease in weight by a mean of 1.47 ± 0.58 kg). Nevertheless, several studies indicated that polyphenols might be effective in preventing small increases in weight during periods of overfeeding rather than reducing weight as such. The outcomes noted do not yet support polyphenol supplementation as a complementary approach in weight loss diets. Further larger trials with a duration of 12 months or more are needed to elucidate the effect of polyphenols on body weight status. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
109.
Abdel‐Hadi Al‐Ja'fari Roser Vila Blanca Freixa Joan Costa Salvador Cañigueral 《Phytotherapy research : PTR》2013,27(6):911-915
The antifungal activity of hexane, dichloromethane, methanol and aqueous extracts from the rhizome and root of Ferula hermonis was assayed in vitro by the agar disk diffusion method against a panel of human opportunistic and pathogenic fungi. Among them, the hexane and dichloromethane extracts showed the highest activity particularly against the dermatophytes Microsporum gypseum and Tricophyton mentagrophytes as well as the yeast Candida lactis‐condensi. Activity‐guided fractionation of both extracts using an agar overlay bioautographic method led to the isolation of two antifungal compounds which were identified as the daucane aryl esters jaeschkeanadiol p‐hydroxybenzoate (ferutinin) and jaeschkeanadiol benzoate (teferidin). Determination of minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values of both compounds evidenced a stronger antifungal activity for ferutinin than for teferidin. Particularly, T. mentagrophytes was the most sensitive strain with MIC and MFC values ranging from 8 to 256 µg/mL. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
110.