全文获取类型
收费全文 | 3860篇 |
免费 | 280篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 93篇 |
妇产科学 | 79篇 |
基础医学 | 575篇 |
口腔科学 | 112篇 |
临床医学 | 421篇 |
内科学 | 797篇 |
皮肤病学 | 82篇 |
神经病学 | 229篇 |
特种医学 | 116篇 |
外国民族医学 | 2篇 |
外科学 | 562篇 |
综合类 | 58篇 |
预防医学 | 273篇 |
眼科学 | 114篇 |
药学 | 318篇 |
中国医学 | 93篇 |
肿瘤学 | 207篇 |
出版年
2024年 | 4篇 |
2023年 | 49篇 |
2022年 | 130篇 |
2021年 | 180篇 |
2020年 | 134篇 |
2019年 | 175篇 |
2018年 | 209篇 |
2017年 | 141篇 |
2016年 | 197篇 |
2015年 | 160篇 |
2014年 | 225篇 |
2013年 | 273篇 |
2012年 | 450篇 |
2011年 | 365篇 |
2010年 | 223篇 |
2009年 | 134篇 |
2008年 | 209篇 |
2007年 | 221篇 |
2006年 | 170篇 |
2005年 | 138篇 |
2004年 | 98篇 |
2003年 | 64篇 |
2002年 | 72篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 16篇 |
1997年 | 4篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1879年 | 1篇 |
排序方式: 共有4170条查询结果,搜索用时 15 毫秒
71.
Shirvani Hossein Rostamkhani Fatemeh Arabzadeh Ehsan Mohammadi Faezeh Mohammadi Fatemeh 《Sport Sciences for Health》2021,17(4):849-854
Sport Sciences for Health - The widespread prevalence and mortality of coronavirus diseases-2019 (COVID-19) lead many researchers to study the SARS-CoV-s2 infection to find a treatment for this... 相似文献
72.
Reza Moghadasali Henricus A.M. Mutsaers Mahnaz Azarnia Nasser Aghdami Hossein Baharvand Ruurd Torensma Martijn J.G. Wilmer Rosalinde Masereeuw 《Experimental and toxicologic pathology》2013,65(5):595-600
Bone marrow-derived mesenchymal stem cells (MSCs) have the capacity to regenerate renal tubule epithelia and repair renal function without fusing with resident tubular cells. The goal of the present project was to investigate the role of MSCs secreted cytokines on tubule cell viability and regeneration after a toxic insult, using a conditionally immortalized human proximal tubule epithelial cell (ciPTEC) line. Gentamicin was used to induce nephrotoxicity, and cell viability and migration were studied in absence and presence of human MSC-conditioned medium (hMSC-CM) i.e. medium containing soluble factors produced and secreted by MSCs. Exposure of ciPTEC to 0–3000 μg/ml gentamicin for 24 h caused a significant dose-dependent increase in cell death. We further demonstrated that the nephrotoxic effect of 2000 μg/ml gentamicin was recovered partially by exposing cells to hMSC-CM. Moreover, exposure of ciPTEC to gentamicin (1500–3000 μg/ml) for 7 days completely attenuated the migratory capacity of the cells. In addition, following scrape-wounding, cell migration of both untreated and gentamicin-exposed cells was increased in the presence of hMSC-CM, as compared to exposures to normal medium, indicating improved cell recovery. Our data suggest that cytokines secreted by MSCs stimulate renal tubule cell regeneration after nephrotoxicity. 相似文献
73.
Eli E. Machtei Georgios Romanos Philip Kang Suncica Travan Stephan Schmidt Evangelos Papathanasiou Nikolaos Tatarakis Moshik Tandlich Leila H. Liberman Jacob Horwitz Seyed Hossein Bassir Srinivas Myneni Harlan J. Shiau Lior Shapira Nikos Donos Athena Papas Joerg Meyle William V. Giannobile Panos N. Papapanou David M. Kim 《Journal of periodontology》2021,92(1):11-20
74.
Neshat Eghbali Homam Naffakh-Moosavy Sanam Sadeghi Mohammadi Hossein Naderi-Manesh 《Dental materials》2021,37(3):547-558
ObjectiveMicro-nano scale surface modification of Ti-6Al-4V was investigated through the fascinated modern fiber engraving laser method. The process was performed at a high laser speed of 2000 mm/s, under different laser frequencies (20–160 kHz) and groove distances (0.5–50 μm).MethodsTopographic evaluations such as Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FE-SEM) were used to identify the quality and regularity of patterns. The proliferation of human osteoblast-like osteosarcoma cells (MG63) was analyzed by MTT assay for up to 72 h. Also, the plate counting method was used to quantify the viability potential of the modified surface against Escherichia coli bacteria.ResultsThe cellular viability of the sample modified at the laser frequency of 20 kHz and grooving distance of 50 μm increased up to 35 and 10% compared to the non-treated and control samples, respectively. In the case of the surface modification at lower grooving distances range between 0.5–50 μm, the maximum laser frequency (160 kHz) applied leads to lower pulse’s energies and less bacterial adhesion. Otherwise, at groove distances more than 50 μm, the minimum laser frequency (20 kHz) applied reduces the laser pulse overlaps, increases the cell adhesion and antibacterial properties.SignificanceSurface modification by the fiber engraving laser process significantly enhances the cell adhesion on the surface. As a result of such roughness and cell adhesion enhancement, the surface toxicity feature diminished, and its antibacterial properties improved. 相似文献
75.
76.
One of the efficient and well-known upconverting nanomaterials is NaYF4:Yb,Er@NaYF4, which emits photoluminescence at 545 nm and 660 nm under an excitation of 980 nm. Here, the nonlinearity of β-NaYF4:Yb,Er@NaYF4 at 532 nm is investigated using three nonlinear approaches. For the first time, the nonlinear optical conjugation of NaYF4:Yb,Er@NaYF4 nanocrystals is observed using the degenerate four-wave mixing method. In the optical bistability study, the optical hysteresis of NaYF4:Yb,Er@NaYF4 is measured using the Mach–Zehnder interferometer nonlinear ring cavity, and the results of bistability loops show different behaviors at different power regimes. Finally, the Z-scan technique is used for determining the nonlinear absorption and refraction coefficients, which are calculated in the order of 10−4 (cm W−1) and 10−8 (cm2 W−1), respectively. The results indicate that by increasing incident powers, optical behaviour changes in both optical bistability and Z-scan. Therefore, the results exhibit that the β-NaYF4:Yb,Er@NaYF4 nanocrystals have nonlinear photoresponses at both 980 and 532 nm, which could be promising for photonic devices based on NIR light and visible light.NaYF4:Yb,Er@NaYF4 is an efficient and well-known upconverting nanomaterials at 980 nm, also it has strong optical nonlinearity at 532 nm related to energy states of the Yb/Er system which is determined by a unique approach. 相似文献
77.
The structure, adsorption characteristics, electronic properties, and charge transfer of SO2 and NO2 molecules on metal-doped gallium nitride nanosheets (M-GaNNSs; M = Ti and Cr) were scrutinized at the Grimme-corrected PBE/double numerical plus polarization (DNP) level of theory. Two types, MGa-GaNNSs and MN-GaNNSs, of doped nanostructures were found. The MGa sites are more stable than the MN sites. The results showed that adsorption of SO2 and NO2 molecules on TiGa,N-GaNNSs is energetically more favorable than the corresponding CrGa,N-GaNNSs. The stability order of complexes is energetically predicted to be as NO2–TiGa-GaNNS > NO2–TiN-GaNNS > SO2–TiGa-GaNNS > NO2–CrN-GaNNS > SO2–TiN-GaNNS > NO2–CrGa-GaNNS > SO2–CrN-GaNNS > SO2–CrGa-GaNNS. The electron population analysis shows that charge is transferred from MGa,N-GaNNSs to the adsorbed gases. The TiGa-GaNNS is more sensitive than the other doped nanostructures to NO2 and SO2 gases. It is estimated that the sensitivity of TiGa-GaNNS to NO2 gas is more than to SO2 gas.The influences of transition metals (Cr and Ti) doping on the adsorption behavior of SO2 and NO2 gases on the metal doped Gallium Nitride Nanosheet (GaNNS) were explored at Grimme-corrected PBE/double numerical plus polarization (DNP) level of theory. 相似文献
78.
A simple, highly versatile and efficient synthesis of 5-phenyl-spiro[diindenopyridine-indenoquinoxaline]-diones is achieved through a four-component one pot reaction of ninhydrin, 1,2-diaminobenzene, 1,3-indandione and aniline. This reaction was catalyzed by MnFe2O4@CS-Bu-SO3H MNPs as a very efficient, recyclable heterogeneous catalyst in acetonitrile under reflux conditions. The catalyst can be recovered from the subsequent reaction mixture and reused for at least five cycles without any appreciable loss in its efficiency. The core–shell structure and composition of the produced magnetic nanocatalyst were analyzed using FT-IR, XRD, VSM, SEM, EDX and TGA techniques.A simply, highly versatile and efficient synthesis of 5-phenyl-spiro [diindeno pyridineindenoquinoxaline]-diones is achieved through five component one pot reaction of ninhydrin, 1,2-diaminobenzene, 1,3-indandione and anilines. 相似文献
79.
Mario?W.?Kramer Christoph?A.?von?Klot Mohammad?Kabbani Abdul-Rahman?Kabbani Hossein?Tezval Inga?Peters Thomas?R.?W.?Herrmann Markus?A.?Kuczyk Axel?S.?MerseburgerEmail author 《World journal of urology》2015,33(10):1373-1380
Purpose
Patients after radical cystectomy (RC) frequently complain about bowel disorders (BDs). Reports addressing related long-term complications are sparse. This cross-sectional study assessed changes in bowel habits (BH) after RC.Methods
A total of 89 patients with a minimum follow-up ≥1 year after surgery were evaluated with a questionnaire. Patients with BD prior to surgery were excluded. Symptoms such as diarrhea, constipation, bloating/flatulence, incomplete defecation, uncontrolled stool loss, and impact on quality of life (QoL) were assessed.Results
A total of 46.1 % of patients reported changes in BH; however, only 25.8 % reported experiencing related dissatisfaction. Primary causes of dissatisfaction were diarrhea and uncontrolled stool loss. The most common complaints were bloating/flatulence and the feeling of incomplete defecation, but these symptoms did not necessarily lead to dissatisfaction or impairment in quality of life. No difference was identified between an orthotopic neobladder and ileal conduit, and even patients without bowel surgery were affected. QoL, health status, and energy level were significantly decreased in unsatisfied patients.Conclusions
About 25 % of patients complain about BDs after RC. More prospective studies assessing symptoms, comorbidities, and dietary habits are necessary to address this issue and to identify strategies for follow-up recommendations.80.