全文获取类型
收费全文 | 4195篇 |
免费 | 410篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 142篇 |
妇产科学 | 187篇 |
基础医学 | 474篇 |
口腔科学 | 137篇 |
临床医学 | 312篇 |
内科学 | 885篇 |
皮肤病学 | 232篇 |
神经病学 | 192篇 |
特种医学 | 220篇 |
外国民族医学 | 8篇 |
外科学 | 590篇 |
综合类 | 90篇 |
预防医学 | 270篇 |
眼科学 | 68篇 |
药学 | 472篇 |
中国医学 | 21篇 |
肿瘤学 | 290篇 |
出版年
2023年 | 51篇 |
2022年 | 150篇 |
2021年 | 228篇 |
2020年 | 159篇 |
2019年 | 239篇 |
2018年 | 262篇 |
2017年 | 205篇 |
2016年 | 195篇 |
2015年 | 215篇 |
2014年 | 226篇 |
2013年 | 292篇 |
2012年 | 322篇 |
2011年 | 312篇 |
2010年 | 209篇 |
2009年 | 166篇 |
2008年 | 149篇 |
2007年 | 160篇 |
2006年 | 150篇 |
2005年 | 143篇 |
2004年 | 111篇 |
2003年 | 99篇 |
2002年 | 98篇 |
2001年 | 18篇 |
2000年 | 17篇 |
1999年 | 27篇 |
1998年 | 17篇 |
1997年 | 20篇 |
1996年 | 19篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 12篇 |
1992年 | 30篇 |
1991年 | 14篇 |
1990年 | 18篇 |
1988年 | 21篇 |
1987年 | 20篇 |
1986年 | 14篇 |
1985年 | 22篇 |
1984年 | 11篇 |
1982年 | 11篇 |
1980年 | 11篇 |
1979年 | 16篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1971年 | 11篇 |
1970年 | 10篇 |
1969年 | 9篇 |
1968年 | 7篇 |
1967年 | 12篇 |
排序方式: 共有4634条查询结果,搜索用时 0 毫秒
91.
92.
Norah K. Alsaif Eman M. Al-Sharif Sarah K. Alsaif Ahmed Mousa Abdulrahman M. Al-Muammar 《Saudi medical journal》2020,41(2):168
Objectives:To report the corneal elevation and thickness values for Saudi myopes and to evaluate the differences between these parameters in subgroups of this target population.Methods:Pentacam corneal topographic maps of the right eyes of patients visiting Al-Hokama Eye Clinic, Riyadh, Saudi Arabia, a tertiary eye center between January 2009 and December 2015 were retrospectively analyzed in this cross-sectional study. The patients were grouped into 3 categories based on their spherical readings: mild (-0.25 to -2.75D), moderate (-3.00 to -5.75D), and severe (≥-6.00D). Furthermore, patients with cylindrical readings of ≥-1.00 diopter were categorized as having myopic astigmatism, whereas those with less than -1.00 cylindrical diopter were categorized as having simple myopia.Results:Our sample was comprised of 1,276 patients; 838 (65.7%) had simple myopia and 438 (34.3%) had myopic astigmatism. The values for the whole myopic group were as follows: anterior corneal elevation (AE) at the apex= 2.60±1.48 (standard deviation), thinnest AE= 2.56±1.68, posterior elevation (PE) at the apex= 3.67±3.58, thinnest PE= 4.92±3.81, central pachymetry= 550.09±34.29, apical pachymetry=550.73±34.64, and thinnest pachymetry= 546.30±34.61. All of the measurements, except the apical PE and thinnest PE, were statistically significant across the simple and myopic astigmatism groups (p<0.05). Comparing the mild to moderate myopia groups revealed a significant difference in the apical AE (p=0.037). Moreover, the comparison between the mild and severe myopia groups revealed that the apical PE and the thinnest PE, as well as the central, apical, and thinnest pachymetry values were statistically significantly different (p<0.05).Conclusion:The corneal elevation indices and thicknesses specific to the Saudi myopes were found to be comparable to the international databases in terms of the elevation and thickness in some of the parameters. 相似文献
93.
Lamia Boubakri A. Chakchouk-Mtibaa Abdullah S. Al-Ayed L. Mansour Nael Abutaha Abdel Halim Harrath L. Mellouli I.
zdemir S. Yasar Naceur Hamdi 《RSC advances》2019,9(59):34406
A series of ruthenium(ii) complexes with N-heterocyclic carbene ligands were successfully synthesized by transmetalation reactions between silver(i) N-heterocyclic carbene complexes and [RuCl2(p-cymene)]2 in dichloromethane under Ar conditions. All new compounds were characterized by spectroscopic and analytical methods. These ruthenium(ii)–NHC complexes were found to be efficient precatalysts for the transfer hydrogenation of ketones by using 2-propanol as the hydrogen source in the presence of KOH as a co-catalyst. The antibacterial activity of ruthenium N-heterocyclic carbene complexes 3a–f was measured by disc diffusion method against Gram positive and Gram-negative bacteria. Compounds 3d exhibited potential antibacterial activity against five bacterial species among the six used as indicator cells. The product 3e inhibits the growth of all the six tested microorganisms. Moreover, the antioxidant activity determination of these complexes 3a–f, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) as reagent, showed that compounds 3b and 3d possess DPPH and ABTS antiradical activities. From a concentration of 1 mg ml−1, these two complexes presented a similar scavenging activity to that of the two used controls gallic acid (GA) and butylated hydroxytoluene (BHT). From a concentration of 10 mg ml−1, the percentage inhibition of complexes 3b and 3d was respectively 70% and 90%. In addition, these two Ru–NHC complexes exhibited antifungal activity against Candida albicans. Investigation of the anti-acetylcholinesterase activity of the studied complexes showed that compounds 3a, 3b, 3d and 3e exhibited good activity at 100 μg ml−1 and product 3d is the most active. In a cytotoxicity study the complexes 3 were evaluated against two human cancer cell lines MDA-MB-231 and MCF-7. Both 3d and 3e complexes were found to be active against the tested cell lines showing comparable activity with examples in the literature.A series of ruthenium(ii) complexes with N-heterocyclic carbene ligands were successfully synthesized by transmetalation reactions between silver(i) N-heterocyclic carbene complexes and [RuCl2(p-cymene)]2 in dichloromethane under Ar conditions. 相似文献
94.
Mohamed A. Dkhil Abdel Azeem S. Abdel-Baki Frank Wunderlich Helmut Sies Saleh Al-Quraishy 《Parasitology research》2014,113(1):267-274
Here, we investigated the effect of the trace element selenium (Se) on course and outcome of Eimeria-paplllata-induced coccidiosis in mice. Male mice were fed on Se-adequate (0.15 ppm), Se-deficient, and Se-high diets (1.0 ppm) for 6 weeks. Mice were orally infected with 1,000 oocysts. The prepatent period lasts for 3 days, but the course of infections varied. At Se-adequate diet, the maximum fecal output of oocysts amounted to 68,300 ooccysts/g feces on day 5 p.i.. However, fecal shedding of oocysts was accelerated in mice on Se-deficient diet and occurred already on day 4 p.i.. By contrast, maximal shedding is impaired in mice on high-Se diet, which takes place on day 5 p.i., but with a decreased output of only 7,300 oocysts/g feces. Light microscopy reveals that all developmental stages are affected: meronts, micro- and macrogamonts, and developing oocysts are increased in comparison with mice fed on selenium-adequate diet. At high Se, the number of parasitic stages in the jejunum is substantially higher than at Se-deficient diet. Se does not affect the number of jejunal Alcian blue-stained goblet cells. Se deficiency increased the number of apoptotic cells in the jejunum. Substantially increased histological injury scores reveal more injuries in jejunum tissue infected by E. papillata. Our data indicate that high dietary Se exerts potential anticoccidial activity. This may be taken advantage of in control measures towards Eimeriosis as a feed additive, potentially alleviating the need for concomitantly utilized anti-coccidial drugs in the feed. 相似文献
95.
96.
97.
Rehab H. Abd El‐Aleam Riham F. George Kevin J. Lee Adam B. Keeton Gary A. Piazza Amr A. Kamel Mahmoud E. El‐Daly Ghaneya S. Hassan Hamdy M. Abdel‐Rahman 《Archiv der Pharmazie》2019,352(8)
A series of 1,2,4‐triazolo[1,5‐a]pyrimidine derivatives was designed, synthesized, and screened for their phosphodiesterase (PDE 4B) inhibitory activity and bronchodilation ability. Compound 7e showed 41.80% PDE 4B inhibition at 10 µM. Eight compounds were screened for their bronchodilator activity, where compounds 7f and 7e elicited promising bronchodilator activity with EC50 values of 18.6 and 57.1 µM, respectively, compared to theophylline (EC50 = 425 µM). Molecular docking at the PDE 4B active site revealed a binding mode and docking scores comparable to those of a reference ligand, consistent with their PDE 4B inhibition activity. 相似文献
98.
99.
100.
Complete or partial thrombosis of the inferior vena cava is usually due to pre-existing malformation of the vessel, malignant tumors, ascending thrombosis, or thrombophilic disorders. We report the case of an 81-year-old woman, in whom a partial thrombosis of the vena cava was observed in the CT scan when re-staging was performed after six cycles of R-CHOP because of high-grade malignant non-Hodgkin lymphoma. Before chemotherapy was started, the patient had undergone an operation of the lumbar spine using cement augmentation. Retrospective analysis showed that cement had penetrated a segmental vein and spilled into the vena cava leading to formation of an adhering blood thrombus. The patient was free of symptoms and anticoagulation was started. Spillage of cement frequently occurs in the process of vertebroplasty and kyphoplasty and may result in serious sequelae. As these procedures are increasingly being used, physicians should be aware of these complications if a patient presents with thrombosis of the caval vein or signs of pulmonary embolism. 相似文献