全文获取类型
收费全文 | 16371篇 |
免费 | 1476篇 |
国内免费 | 73篇 |
专业分类
耳鼻咽喉 | 233篇 |
儿科学 | 556篇 |
妇产科学 | 396篇 |
基础医学 | 1988篇 |
口腔科学 | 432篇 |
临床医学 | 1201篇 |
内科学 | 3618篇 |
皮肤病学 | 602篇 |
神经病学 | 931篇 |
特种医学 | 754篇 |
外国民族医学 | 6篇 |
外科学 | 2792篇 |
综合类 | 171篇 |
一般理论 | 3篇 |
预防医学 | 1225篇 |
眼科学 | 457篇 |
药学 | 1301篇 |
中国医学 | 92篇 |
肿瘤学 | 1162篇 |
出版年
2023年 | 127篇 |
2022年 | 418篇 |
2021年 | 627篇 |
2020年 | 421篇 |
2019年 | 681篇 |
2018年 | 871篇 |
2017年 | 600篇 |
2016年 | 634篇 |
2015年 | 572篇 |
2014年 | 802篇 |
2013年 | 1087篇 |
2012年 | 1253篇 |
2011年 | 1380篇 |
2010年 | 881篇 |
2009年 | 795篇 |
2008年 | 890篇 |
2007年 | 865篇 |
2006年 | 820篇 |
2005年 | 677篇 |
2004年 | 620篇 |
2003年 | 423篇 |
2002年 | 423篇 |
2001年 | 308篇 |
2000年 | 320篇 |
1999年 | 233篇 |
1998年 | 95篇 |
1997年 | 74篇 |
1996年 | 67篇 |
1995年 | 44篇 |
1994年 | 39篇 |
1993年 | 39篇 |
1992年 | 35篇 |
1991年 | 40篇 |
1990年 | 28篇 |
1989年 | 26篇 |
1988年 | 30篇 |
1987年 | 26篇 |
1985年 | 29篇 |
1984年 | 86篇 |
1983年 | 69篇 |
1982年 | 42篇 |
1981年 | 27篇 |
1980年 | 42篇 |
1979年 | 45篇 |
1978年 | 44篇 |
1977年 | 33篇 |
1976年 | 35篇 |
1975年 | 38篇 |
1974年 | 20篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Mohamed El Sayes Ahmed Kandeil Yassmin Moatasim Ahmed El Taweel Adam Rubrum Omnia Kutkat Mina Nabil Kamel Rebecca Badra Ahmed B. Barakat Pamela P. McKenzie Rabeh El-Shesheny Richard J. Webby Ghazi Kayali Mohamed Ahmed Ali 《Viruses》2022,14(7)
From 2010 to 2013, genotype I avian influenza A(H9N2) viruses of the G1-lineage were isolated from several poultry species in Egypt. In 2014, novel reassortant H9N2 viruses were detected in pigeons designated as genotype II. To monitor the subsequent genetic evolution of Egyptian A(H9N2) viruses, we characterized the full genomes of 173 viruses isolated through active surveillance from 2017 to 2022. In addition, we compared the virological characteristics and pathogenicity of representative viruses. Phylogenetic analysis of the HA indicated that all studied sequences from 2017–2021 were grouped into G1-like H9N2 viruses previously detected in Egypt. Phylogenetic analysis indicated that the Egyptian A(H9N2) viruses had undergone further reassortment, inheriting four genes (PB2, PB1, PA, NS) from genotype II, with their remaining segments deriving from genotype I viruses (these viruses designated as genotype III). Studying the virological features of the two most dominant genotypes (I and III) of Egyptian H9N2 viruses in vitro and in vivo indicated that both replicated well in mammalian cells, but did not show any clinical signs in chickens, ducks, and mice. Monitoring avian influenza viruses through surveillance programs and understanding the genetic and antigenic characteristics of circulating H9N2 viruses are essential for risk assessment and influenza pandemic preparedness. 相似文献
132.
Guilmot Antoine Maldonado Slootjes Sofia Sellimi Amina Bronchain Maroussia Hanseeuw Bernard Belkhir Leila Yombi Jean Cyr De Greef Julien Pothen Lucie Yildiz Halil Duprez Thierry Fillée Catherine Anantharajah Ahalieyah Capes Antoine Hantson Philippe Jacquerye Philippe Raymackers Jean-Marc London Frederic El Sankari Souraya Ivanoiu Adrian Maggi Pietro van Pesch Vincent 《Journal of neurology》2021,268(3):751-757
Journal of Neurology - Evidence of immune-mediated neurological syndromes associated with the severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection is limited. We therefore... 相似文献
133.
Hanan Ahabrach Blanca Piedrafita Abdelmalik Ayad Nisrin El Mlili Mohammed Errami Vicente Felipo Marta Llansola 《Journal of neuroscience research》2010,88(7):1605-1614
Patients with liver cirrhosis may present hepatic encephalopathy with a wide range of neurological disturbances and alterations in sleep quality and in the sleep‐wake circadian rhythm. Hyperammonemia is a main contributor to the neurological alterations in hepatic encephalopathy. We have assessed, in an animal model of chronic hyperammonemia without liver failure, the effects of hyperammonemia per se on the circadian rhythms of motor activity, temperature, and plasma levels of adrenal corticosteroid hormones. Chronic hyperammonemia alters the circadian rhythms of locomotor activity and of cortisol and corticosterone levels in blood. Different types of motor activity are affected differentially. Hyperammonemia significantly alters the rhythm of spontaneous ambulatory activity, reducing strongly ambulatory counts and slightly average velocity during the night (the active phase) but not during the day, resulting in altered circadian rhythms. In contrast, hyperammonemia did not affect wheel running at all, indicating that it affects spontaneous but not voluntary activity. Vertical activity was affected only very slightly, indicating that hyperammonemia does not induce anxiety. Hyperammonemia abolished completely the circadian rhythm of corticosteroid hormones in plasma, completely eliminating the peaks of cortisol and corticosterone present in control rats at the start of the dark period. The data reported show that chronic hyperammonemia, similar to that present in patients with liver cirrhosis, alters the circadian rhythms of corticosteroid hormones and of motor activity. This suggests that hyperammonemia would be a relevant contributor to the alterations in corticosteroid hormones and in circadian rhythms in patients with liver cirrhosis. © 2009 Wiley‐Liss, Inc. 相似文献
134.
Mona E. El Sharkasy Manar M. Tolba Fathalla Belal Mohamed I. Walash Rasha Aboshabana 《RSC advances》2022,12(22):13826
In this study, highly fluorescent water-soluble nitrogen and sulfur doped carbon quantum dots (N, S-CQDs) were synthesized via a one-step hydrothermal process utilizing citric acid as a carbon source and thiosemicarbazide as a sulfur and nitrogen source. The obtained N, S-CQDs exhibited an intense emission band at 415 nm (λex = 345 nm). In the presence of either piroxicam, tenoxicam or lornoxicam, the emission band at 415 nm was significantly quenched which might be triggered due to destruction of the surface passivation layer of the N, S-CQDs. A linear correlation was found between the reduction in the fluorescence intensity of N, S-CQDs and the concentration of each drug in the ranges of 2.0–25.0 μM, 10.0–100.0 μM and 20.0–200.0 μM with correlation coefficients of more than 0.999 for all drugs. The detection limits were 0.49 μM, 1.58 μM and 4.63 μM for piroxicam, tenoxicam and lornoxicam, respectively. The effect of experimental parameters affecting the performance of the method was investigated and optimized. The developed sensor has the advantages of simplicity, time-saving, convenience and satisfactory selectivity for determination of the studied drugs in dosage forms with high % recoveries (98.86–101.69%). The method was extended for determination of piroxicam in spiked plasma with % recoveries ranging from 97.95–101.36%. The method was validated in accordance with International Council of Harmonization (ICH) standards, and the results obtained were compared statistically to those given by reported methods, indicating no significant differences in the level of accuracy and precision. The mechanism of the quenching process was studied and elucidated. The structure–activity relationship between the three drugs and the quenching efficiency was also studied and discussed.Highly fluorescent nitrogen and sulfur doped carbon quantum dots were synthesized via hydrothermal process using citric acid and thiosemicarbazide. The dots had an emission band at 415 nm (λex = 345 nm). The polarity of the studied drugs affects the method’s sensitivity. 相似文献
135.
Maher El Chaar Peter Lundberg Jill Stoltzfus 《Surgery for obesity and related diseases》2018,14(5):545-551
Background
According to recent American Society for Metabolic and Bariatric Surgery estimates, sleeve gastrectomy (SG) is now the most commonly performed procedure in the United States (~53.8% of all bariatric procedures), followed by Roux-en-Y gastric bypass (RYGB; 23.1% of all procedures).Objectives
The objective of this study was to evaluate outcomes and safety of these 2 procedures in the first 30 days postoperatively using the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program data registry.Setting
University health network, United States.Methods
We reviewed all SG and RYGB cases entered between January 1 and December 31, 2015 in the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program data registry. Demographic characteristics and 30-day outcomes were analyzed based on separate Mann-Whitney rank sums tests, χ2, or Fisher's exact tests as appropriate, with P<.05 denoting statistical significance and no adjustment for multiple testing.Results
A total of 141,646 patients were analyzed; 98,292 underwent SG and 43,354 underwent RYGB. Average age was 44.5 and 45.4 years for SG and RYGB, respectively. Preoperative body mass index was 45.1 and 46.1 for SG and RYGB, respectively. The 30-day mortality was .1% for SG and .2% for RYGB (P<.05). The incidence of unplanned intensive care unit admission after RYGB was twice as high compared with SG (1.3% versus .6%, respectively, P<.05). The incidence of at least 1 intervention or reoperation after RYGB was significantly higher compared with SG (2.8% and 2.5% for GB versus 1.2% and 1% for SG, P<.05). After RYGB, .4% of patients had a drain left in place at 30 days postoperatively versus .3% for SG (P<.05). The incidence of readmission was 2.8% for RYGB and 1.2% for SG (P<.05).Conclusions
The incidence of postoperative complications in the first 30 days after surgery is low for both RYGB and SG. However, SG seems to have a better safety profile in the first 30 days postoperatively compared with RYGB. These findings should be considered in the preoperative evaluation and counseling of bariatric patients. Long-term follow-up is needed to compare safety and efficacy of SG versus RYGB. 相似文献136.
Khalid I. Hussein Mohammed S. Alqahtani Arwa A. Meshawi Khloud J. Alzahrani Heba Y. Zahran Ali M. Alshehri Ibrahim S. Yahia Manuela Reben El Sayed Yousef 《Materials》2022,15(9)
In this study, the X-ray and gamma attenuation characteristics and optical properties of a synthesized tellurite–phosphate–sodium oxide glass system with a composition of (85 − x)TeO2–10P2O5–xNa2O mol% (where x = 15, 20, and 25) were evaluated. The glass systems we re fabricated by our research group using quenching melt fabrication. The shielding parameters of as-synthesized systems, such as the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), effective atomic number (Zeff), half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), and effective electron density (Neff) in a wide energy range between 15 keV and 15 MeV, were estimated using well-known PHY-X/PSD software and recently developed MIKE software. Herein, the optical parameters of prepared glasses, such as molar volume (VM), oxygen molar volume (VO), oxygen packing density (OPD), molar polarizability (), molar refractivity (Rm), reflection loss (RL), and metallization (M), were estimated using MIKE software. Furthermore, the shielding performance of the prepared glasses was compared with that of commonly used standard glass shielding materials. The results show that the incorporation of sodium oxide into the matrix TeO2/P2O5 with an optimum concentration can yield a glass system with good shielding performance as well as good optical and physical properties, especially at low photon energy. 相似文献
137.
Hind Sahli Jihad Boularab Jihane El Mandour Nazik Allali Latifa Chat Siham El Haddad 《Radiology Case Reports》2022,17(7):2315
Extramedullary hematopoiesis is a rare disorder in which hematopoietic cells proliferate in tissues other than the bone marrow as a result of a range of hematologic illnesses. Our case is unique in that it covers a number of extramedullary hematopoiesis sites in a 15-year-old girl, some of which are uncommon. 相似文献
138.
139.
140.
Maguy Saffouh El Hajj Reem Hasan EL-Ajez Muna Said Mohd Al-Ismail Diaa Mujahed Sawaftah 《International journal of clinical pharmacy》2012,34(6):885-892
Background In Qatar, home diagnostic tests are available over the counter in community pharmacies. While possibly beneficial, these tests have the potential for harm if they are used in the absence of pharmacist counseling. Objectives To determine the public views, level of awareness and use of home diagnostic tests and to evaluate the extent of community pharmacists?? involvement in educating the public about these tests in Qatar. Setting Qatar??s Supreme Council of Health lists 245 community pharmacies in Qatar. Ten community pharmacies were randomly selected from the list as study sites. Method The investigators visited selected pharmacies on different weekdays and at different times of the day. Members of the public who appeared to be over 16?years of age and able to communicate in English or Arabic were randomly approached, provided with the study objectives, and requested to participate. Those who offered oral consent were anonymously interviewed using a multipart survey. Main outcome measures Measures include the public awareness and use of home diagnostic tests and the extent of community pharmacist involvement in educating the public about these tests. Results During the 5-month study period, 297 patients answered the survey (60?% response rate). Most respondents were aware of at least one home diagnostic test (98?%). The top four home diagnostic tests that the respondents had ever heard of included: thermometers (91?%), blood pressure monitors (91?%), blood sugar tests (86?%) and regular pregnancy tests (72?%). Seventy-one percent of respondents had performed at least one home diagnostic test. When asked about the factors that influenced their choice of the home diagnostic tests, the pharmacist was only cited by 7?% of respondents. The majority of respondents (>80?%) agreed that using a home diagnostic test is convenient, comfortable and helps them in early diagnosis and treatment of healthcare conditions. Only 31?% agreed that the pharmacist offered sufficient information on what to do in case the test result turns to be positive. The study results suggest that generally, the public has good attitudes and awareness of home diagnostic tests. However, the results indicate that Qatar community pharmacists are not sufficiently involved in public education about home diagnostic tests. Pharmacists should take a more active role in counseling the public on the proper use of these tests. 相似文献