全文获取类型
收费全文 | 859497篇 |
免费 | 49473篇 |
国内免费 | 1695篇 |
专业分类
耳鼻咽喉 | 11688篇 |
儿科学 | 27517篇 |
妇产科学 | 20982篇 |
基础医学 | 130136篇 |
口腔科学 | 25344篇 |
临床医学 | 73195篇 |
内科学 | 170309篇 |
皮肤病学 | 20925篇 |
神经病学 | 61473篇 |
特种医学 | 29053篇 |
外国民族医学 | 78篇 |
外科学 | 122284篇 |
综合类 | 15767篇 |
现状与发展 | 2篇 |
一般理论 | 202篇 |
预防医学 | 65892篇 |
眼科学 | 19582篇 |
药学 | 64294篇 |
21篇 | |
中国医学 | 3185篇 |
肿瘤学 | 48736篇 |
出版年
2021年 | 9564篇 |
2019年 | 9385篇 |
2018年 | 13199篇 |
2017年 | 9296篇 |
2016年 | 9861篇 |
2015年 | 10933篇 |
2014年 | 14817篇 |
2013年 | 21943篇 |
2012年 | 30752篇 |
2011年 | 32557篇 |
2010年 | 18547篇 |
2009年 | 16432篇 |
2008年 | 28503篇 |
2007年 | 30489篇 |
2006年 | 30224篇 |
2005年 | 28735篇 |
2004年 | 27393篇 |
2003年 | 25801篇 |
2002年 | 24814篇 |
2001年 | 40308篇 |
2000年 | 41443篇 |
1999年 | 33939篇 |
1998年 | 8666篇 |
1997年 | 7260篇 |
1996年 | 7463篇 |
1995年 | 7052篇 |
1994年 | 6439篇 |
1992年 | 24358篇 |
1991年 | 24094篇 |
1990年 | 23353篇 |
1989年 | 22937篇 |
1988年 | 20790篇 |
1987年 | 20103篇 |
1986年 | 19176篇 |
1985年 | 17903篇 |
1984年 | 13127篇 |
1983年 | 11105篇 |
1982年 | 6142篇 |
1979年 | 11921篇 |
1978年 | 8401篇 |
1977年 | 7046篇 |
1976年 | 6815篇 |
1975年 | 7550篇 |
1974年 | 8855篇 |
1973年 | 8507篇 |
1972年 | 7972篇 |
1971年 | 7462篇 |
1970年 | 7187篇 |
1969年 | 6635篇 |
1968年 | 6073篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Background
Patients with Diabetic Foot Ulcer (DFU) show high levels of depression and anxiety symptoms. The loss of a limb is undoubtedly a devastating experience and several studies have shown that anxiety and depression symptoms are a common reaction after a lower limb amputation (LLA). However, no study has focused on the immediate emotional reactions to LLA as a personal factor based on the ICF Model.Objective
This study focused on the characterization of anxiety and depression levels, before and after surgery, differences in levels of depression and anxiety before and after surgery and the predictors of anxiety and depression one month after surgery, in a sample of patients with DFU.Methods
This was a longitudinal study with 179 patients with Diabetes Mellitus Type 2 and DFU indicated for amputation, screened for the presence of anxiety and depression symptoms during the hospitalization that preceded amputation and one month after surgery, during a follow-up consultation.Results
The results showed a significant effect of anxiety and depression symptoms at pre-surgery in the prediction of anxiety and depression symptoms one month after LLA. Patients showed higher levels of anxiety than depression symptoms at pre-surgery, although anxiety significantly decreased on month after surgery. Both anxiety and depression symptoms contributed to depression after LLA, although anxiety at pre-surgery was the only predictor of anxiety at post-surgery.Conclusions
Tailored multidisciplinary interventions need to be developed providing support before and after an amputation surgery, in order to reduce anxiety and depression symptoms and promote psychological adjustment to limb loss. 相似文献46.
Javariya Aamir Syed Mustafa Ali Maged N. Kamel Boulos Naveed Anjum Muhammad Ishaq 《Health Policy and Technology》2018,7(1):88-97
Objective
The objective of this review is to identify enabling and inhibiting factors for mHealth adoption in low resource settings, by giving emphasis on the stakeholders representing the caregiving side. Another objective of this study is to support implementation agencies (governmental and non-governmental) in designing scalable mHealth interventions.Methods
A PEO (Population, Exposure, Outcome) approach was used to formulate the review question. A pre-defined search strategy was implemented; Google Scholar, PubMed and gray literature were searched using alternate terms for “mHealth”, “adoption” and “developing countries”. CASP [7] tools were used to assess the quality of selected evidence. After applying inclusion and exclusion criteria on search results and critical appraisal of the selected evidence, twelve studies were selected for the review.Results
Adoption factors operated at the levels of organization, facility-based service provider and frontline health worker. Engagement of end users during design phase, informed clinical decision making, utilization of mHealth evidence, employers’ tolerance of some personal use of devices, automation of tasks and user-friendliness of application are key enabling factors for mHealth adoption in developing countries. On the contrary, absence of national policy on mHealth, poor knowledge base on mHealth, using two systems in parallel, duplication of efforts, poor Internet connectivity and shortage of electricity are important inhibiting factors for mHealth adoption.Conclusions
The review provides an insight about the challenges and opportunities related to mHealth adoption in developing countries. Implementation agencies should give careful consideration to these factors before designing and deploying any mHealth-enabled intervention. It is also important to understand the concept of incremental innovation so that resources spent on pilot interventions are optimized and full potential is achieved. 相似文献47.
Luis Alfonso Ortíz-Reyes Lilia Castillo-Martínez Arianne Itzel Lupián-Angulo Daniel Dante Yeh Héctor Isaac Rocha-González Aurora Elizabeth Serralde-Zúñiga 《Journal of the Academy of Nutrition and Dietetics》2018,118(1):52-61
Background
Unintentional underfeeding is common in patients receiving enteral nutrition (EN), and is associated with increased risk of malnutrition complications. Protocols for EN in critically ill patients have been shown to enhance adequacy, resulting in better clinical outcomes; however, outside of intensive care unit (ICU) settings, the influence of a protocol for EN is unknown.Objective
To evaluate the efficacy and safety of implementing an EN protocol in a noncritical setting.Design
Randomized controlled clinical trial.Participants and settings
This trial was conducted from 2014 to 2016 in 90 adult hospitalized patients (non-ICU) receiving exclusively EN. Patients with carcinomatosis, ICU admission, or <72 hours of EN were excluded.Intervention
The intervention group received EN according to a protocol, whereas the control group was fed according to standard practice.Main outcome measures
The proportion of patients receiving ≥80% of their caloric target at Day 4 after EN initiation.Statistical analyses performed
Student t test or Wilcoxon rank-sum test were used for continuous variables and the difference between the groups in the time to receipt of the optimal amount of nutrition was analyzed using Kaplan-Meier curves.Results
Forty-five patients were randomized to each group. At Day 4 after EN initiation, 61% of patients in the intervention arm had achieved the primary end point compared with 23% in the control group (P=0.001). In malnourished patients, 63% achieved the primary end point in the intervention group compared with 16% in the control group (P=0.003). The cumulative deficit on Day 4 was lower in the intervention arm compared with the control arm: 2,507 kcal (interquartile range [IQR]=1,262 to 2,908 kcal) vs 3,844 kcal (IQR=2,620 to 4,808 kcal) (P<0.001) and 116 g (IQR=69 to 151 g) vs 191 g (IQR=147 to 244 g) protein (P<0.001), respectively. The rates of gastrointestinal complications were not significantly different between groups.Conclusions
Implementation of an EN protocol outside the ICU significantly improved the delivery of calories and protein when compared with current standard practice without increasing gastrointestinal complications. 相似文献48.
Amelia N. Deitchman Ravi Shankar Prasad Singh Hartmut Derendorf 《Journal of pharmaceutical sciences》2018,107(7):1754-1760
Nonlinear protein binding is traditionally thought of as an increasing fraction unbound with increasing total drug concentration. In the past several years, research into the protein binding of several tetracyclines has shown that an unexpected and counterintuitive phenomenon has been observed, specifically that of decreasing unbound drug fraction with increasing total concentrations of drug over certain concentration ranges. Although several studies of tigecycline have shown the importance calcium and its chelation may play in the protein-drug interaction, the potential clinical implications and relevance have not been explored. Here, we define typical and atypical nonlinear protein binding, overview protein binding theory, and discuss theoretical implications on pharmacokinetics. Using tigecycline as an example, in silico simulations and calculations show how when atypical nonlinear protein binding is not accounted for free drug exposure, and drug tissue penetration may be overestimated. It is important to revisit the impacts of nonlinearity in protein binding on clinical pharmacokinetics and pharmacodynamics, and ultimately, clinical efficacy. Although this phenomenon could potentially warrant clinical dose adjustment for certain compounds, it also presents a potential opportunity to exploit underlying mechanisms to develop new therapies and better understand molecular interactions of xenobiotics within the physiological system. 相似文献
49.
Iman M.N. Hamdan Ismaiel A. Tekko Kyle B. Matchett Luis G. Arnaut Claudia S. Silva Helen O. McCarthy Ryan F. Donnelly 《Journal of pharmaceutical sciences》2018,107(9):2439-2450
Nodular basal cell carcinoma is a deep skin lesion and one of the most common cancers. Conventional photodynamic therapy is limited to treatment of superficial skin lesions. The parenteral administration of near-IR preformed photosensitizers suffers from poor selectivity and may result in prolonged skin photosensitivity. Microneedles (MNs) can provide localized drug delivery to skin lesions. Intradermal delivery of the preformed near-IR photosensitizer; 5,10,15,20-tetrakis(2,6-difluoro-3-N-methylsulfamoylphenyl bacteriochlorin (Redaporfin?) using dissolving MN was successful in vitro and in vivo. MN demonstrated complete dissolution 30 min after skin application and showed sufficient mechanical strength to penetrate the skin to a depth of 450 μm. In vitro deposition studies illustrated that the drug was delivered and detected down to 5 mm in skin. In vivo biodistribution studies in athymic nude mice Crl:NU(NCr)-Foxn1nu showed both fast initial release and localized drug delivery. The MN-treated mice showed a progressive decrease in the fluorescence intensity at the application site over the 7-day experiment period, with the highest and lowest fluorescence intensities measured being 9.2 × 1010 ± 2.5 × 1010 and 3.8 × 109 ± 1.6 × 109 p/s, respectively. By day 7, there was some migration of fluorescence away from the site of initial MN application. However, the majority of the body surfaces showed fluorescence levels that were comparable to those seen in the negative control group. This work suggests utility for polymeric MN arrays in minimally invasive intradermal delivery to enhance photodynamic therapy of deep skin lesions. 相似文献
50.
Verônica M. Couto Maria J. Prieto Daniela E. Igartúa Daniela A. Feas Lígia N.M. Ribeiro Camila M.G. Silva Simone R. Castro Viviane A. Guilherme Darlene D. Dantzger Daisy Machado Silvia del V. Alonso Eneida de Paula 《Journal of pharmaceutical sciences》2018,107(9):2411-2419
Administration of local anesthetics is one of the most effective pain control techniques for postoperative analgesia. However, anesthetic agents easily diffuse into the injection site, limiting the time of anesthesia. One approach to prolong analgesia is to entrap local anesthetic agents in nanostructured carriers (e.g., liposomes). Here, we report that using an ammonium sulphate gradient was the best strategy to improve the encapsulation (62.6%) of dibucaine (DBC) into liposomes. Light scattering and nanotracking analyses were used to characterize vesicle properties, such as, size, polydispersity, zeta potentials, and number. In vitro kinetic experiments revealed the sustained release of DBC (50% in 7 h) from the liposomes. In addition, in vitro (3T3 cells in culture) and in vivo (zebrafish) toxicity assays revealed that ionic-gradient liposomes were able to reduce DBC cyto/cardiotoxicity and morphological changes in zebrafish larvae. Moreover, the anesthesia time attained after infiltrative administration in mice was longer with encapsulated DBC (27 h) than that with free DBC (11 h), at 320 μM (0.012%), confirming it as a promising long-acting liposome formulation for parenteral drug administration of DBC. 相似文献