首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2171篇
  免费   172篇
  国内免费   125篇
耳鼻咽喉   17篇
儿科学   12篇
妇产科学   3篇
基础医学   285篇
口腔科学   16篇
临床医学   113篇
内科学   245篇
皮肤病学   83篇
神经病学   8篇
特种医学   24篇
外科学   29篇
综合类   268篇
预防医学   301篇
眼科学   13篇
药学   554篇
中国医学   346篇
肿瘤学   151篇
  2024年   4篇
  2023年   37篇
  2022年   37篇
  2021年   91篇
  2020年   83篇
  2019年   70篇
  2018年   55篇
  2017年   87篇
  2016年   92篇
  2015年   98篇
  2014年   130篇
  2013年   213篇
  2012年   146篇
  2011年   173篇
  2010年   138篇
  2009年   94篇
  2008年   105篇
  2007年   67篇
  2006年   109篇
  2005年   83篇
  2004年   64篇
  2003年   79篇
  2002年   52篇
  2001年   45篇
  2000年   26篇
  1999年   30篇
  1998年   22篇
  1997年   19篇
  1996年   16篇
  1995年   20篇
  1994年   27篇
  1993年   8篇
  1992年   23篇
  1991年   18篇
  1990年   20篇
  1989年   10篇
  1988年   7篇
  1987年   6篇
  1986年   6篇
  1985年   14篇
  1984年   4篇
  1983年   8篇
  1982年   5篇
  1981年   6篇
  1980年   3篇
  1979年   6篇
  1978年   6篇
  1977年   3篇
  1976年   2篇
  1973年   1篇
排序方式: 共有2468条查询结果,搜索用时 15 毫秒
1.
目的:调查药食两用薏苡仁中污染真菌多样性,为其安全使用提供参考依据。方法:收集薏苡仁样品18批,提取真菌DNA并扩增ITS2序列,基于Illumina MiSeq PE250平台进行高通量测序。结果:共检测到4门18纲44目99科149属的真菌,子囊菌门Ascomycota是最优势菌门,镰刀菌属Fusarium(3.05%~60.32%)是属水平最优势属,其次是曲霉属Aspergillus(2.20%~45.44%)、白僵菌属Beauveria(0.07%~63.21%)、链格孢属Alternaria(0.80%~11.92%)、Arachnomyces(0.03%~39.36%)和青霉属Penicillium(0.24%~8.03%)。此外,共检测到5种潜在产毒真菌,分别是烟曲霉A.fumigatus、土曲霉A.terreus、梨孢镰刀菌F.poae、囊状青霉P.capsulatum和展青霉P.paxilli。结论:高通量测序技术可以快速有效地检测薏苡仁中污染真菌种类,为薏苡仁污染真菌毒素提供风险预警。  相似文献   
2.
Objective: Despite advanced treatment options available, drug resistance develops in breast cancer (BC) patientsrequiring novel effective drugs. Stylissa carteri, a marine sponge predominantly living in Indonesia territories, hasnot been extensively studied as anti-cancer. Therefore, this study targeted to assess the anti-tumor activity of theethanol extract of S. carteri in BC cells. Methods: S. carteri was collected from Pramuka Island, at Kepulauan SeribuNational Park, Jakarta, Indonesia and extracted using ethanol. Different BC cells including MDA MB 231, MDAMB 468, SKBR3, HCC-1954 and MCF-7 cells were treated with this extract for cytotoxic analysis using MTT assay.Spheroid growth assay and apoptosis assay were conducted in HCC-1954 cells. In addition, cell migration analysis andsynergistic activity with doxorubicin or paclitaxel were conducted in MDA MB 231 cells. This extract was subjectedalso for GC-MS analysis. Results: The results show that ethanol extract of S. carteri demonstrated a cytotoxic activityin BC cells. The IC50 of this extract was lower 15 μg/ml in MDA MB 231, MDA MB 468, SKBR3, and HCC-1954cells. Moreover, this extract inhibited spheroids growth and induced apoptosis in HCC-1954 cells. It inhibited cellmigration and demonstrated a synergistic activity with doxorubicin or paclitaxel on triggering cell death in MDA MB231 cells. Furthermore, GC-MS analysis indicated that this extract contained 1,2-Benzenediol, Dibutyl phthalate and9,12-Octadecadienoic acid, ethyl ester. Conclusion: Our preliminary data indicate a potential anti-tumor activity ofethanol extract of S. carteri in breast cancer cells.  相似文献   
3.
4.
Phaeohyphomycosis is a chronic subcutaneous fungal infection caused by dematiaceous fungi, commonly involving the extremities, which present as single or multiple lesions mimicking a benign tumor. Fine‐needle aspiration cytology (FNAC) is an easy method for the diagnosis of the lesion. Morphology of the fungus is characteristic with no difficulty for cytopathologist for identification; with a close differential diagnosis of Candida and Aspergillosis. The special stains like periodic acid schiff (PAS) highlights the fungus and the Masson Fontana confirm the melanin pigment and dematiaceous nature of the fungi. Liquid‐based cytology (LBC) preparation of the aspirated material was attempted, which is not usually performed on day to day basis. However, in our case the conventional smears were better for appreciating the fungal morphology.  相似文献   
5.
6.
目的: 对海洋生物医用材料在医疗领域的应用情况和海洋生物材料来源医疗器械的安全性评价趋势进行分析,为推进该材料的临床转化提供参考。方法: 归纳海洋生物医用材料的分类和应用,介绍该材料的安全性评价的程序要点,探讨其安全性评价中面临的挑战。结果与结论: 常用的海洋生物医用材料主要为多糖和蛋白质,在创伤修复和组织工程领域应用广泛。海洋生物医用材料具有生物活性和良好的生物相容性,对此类材料的安全性评价应根据材料特性和预期用途,科学制定评价程序和选择检验方法。  相似文献   
7.
Gastrodia elata Bl. is a traditional Chinese herbal medicine with special pharmacological effects on headache and numbness. However, its wild sources are now in short supply because of over-excavation. A total of 14 endophytic fungi were isolated from Gastrodia elata Bl collected from Yinjing, in which 10 strains were identified, including Neonectria, Ascomycota, Fusarium, Oidiodendron and Dothiorella. All crude extracts showed some degrees of antioxidant activities by T-AOC method and DPPH methods, especially those from Oidiodendron GeR6 and Ascomycota sp. GeR2, which might be attributed due to their high phenolic contents. However, only Oidiodendron GeR6 contained gastrodin (39.2 μg/g) as the host plant in the crude extracts. In conclusion, the notable activities of GeR6 indicated its medical use as a natural antioxidant agent, as well as substitutable use for Gastrodia elata Bl. in the future.  相似文献   
8.
We report a case of cerebral phaeohyphomycosis, a fungal brain infection due to a dark (dematiaceous) fungi in a 6-year-old French Guyanese boy. The child presented fever and drowsiness due to several paraventricular brain abscesses. Neurological surgeries were performed to reduce intracranial hypertension and to obtain abscess biopsies. Mycological cultures of intraoperative samples led to the diagnosis of cerebral phaeohyphomycosis due to Cladophialophora bantiana. The patient neurological status deteriorated and remained critical after several weeks of combination antifungal therapy with voriconazole 8 mg/kg/day, liposomal amphotericin B 10 mg/kg/day and flucytosine 200 mg/kg/day. A complete surgical resection was not possible because of multiple small abscesses. A multidisciplinary ethical staff decided on home medical care with palliative ventriculoperitoneal shunt, nasogastric feeding and analgesics. One year later, the patient's neurological condition had improved and cerebral lesions had regressed, while he had not received any antifungal treatment but only traditional medicines. Cerebral phaeohyphomycosis are rare diseases affecting immunocompromised but also apparently non-immunocompromised patients, as in this case. A complete surgical resection is not always possible and mortality rates are high in spite of treatments with a combination of antifungals. The diagnosis may be difficult because of these dematiaceous fungi's slowly growing and their potential pathogenicity for laboratory staff.  相似文献   
9.
目的分析厦门地区儿童甲真菌病的临床特点、危险因素及病原菌分布情况。方法收集两所医院112例儿童甲真菌病的临床资料,分析其临床特点、危险因素及病原菌特点。结果 112例甲真菌病患儿,发病的主要年龄段为10~12岁,临床类型最多的是远端侧位甲下型,趾甲的患病率明显高于指甲。真菌培养阳性率为80.36%,分离出病原菌90株,其中皮肤癣菌76株,占84.44%,而红色毛癣菌为主要致病菌。结论儿童甲真菌病在临床特点及病原菌分布上有其自身的特点,要注意避免其发病的危险因素。  相似文献   
10.
Ice nucleating particles (INPs) are vital for ice initiation in, and precipitation from, mixed-phase clouds. A source of INPs from oceans within sea spray aerosol (SSA) emissions has been suggested in previous studies but remained unconfirmed. Here, we show that INPs are emitted using real wave breaking in a laboratory flume to produce SSA. The number concentrations of INPs from laboratory-generated SSA, when normalized to typical total aerosol number concentrations in the marine boundary layer, agree well with measurements from diverse regions over the oceans. Data in the present study are also in accord with previously published INP measurements made over remote ocean regions. INP number concentrations active within liquid water droplets increase exponentially in number with a decrease in temperature below 0 °C, averaging an order of magnitude increase per 5 °C interval. The plausibility of a strong increase in SSA INP emissions in association with phytoplankton blooms is also shown in laboratory simulations. Nevertheless, INP number concentrations, or active site densities approximated using “dry” geometric SSA surface areas, are a few orders of magnitude lower than corresponding concentrations or site densities in the surface boundary layer over continental regions. These findings have important implications for cloud radiative forcing and precipitation within low-level and midlevel marine clouds unaffected by continental INP sources, such as may occur over the Southern Ocean.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号