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   52330篇
  免费   4507篇
  国内免费   956篇
耳鼻咽喉   268篇
儿科学   2491篇
妇产科学   877篇
基础医学   5434篇
口腔科学   1007篇
临床医学   6833篇
内科学   8141篇
皮肤病学   702篇
神经病学   849篇
特种医学   821篇
外国民族医学   1篇
外科学   5983篇
综合类   7443篇
现状与发展   7篇
预防医学   10170篇
眼科学   337篇
药学   4236篇
  44篇
中国医学   1030篇
肿瘤学   1119篇
  2024年   157篇
  2023年   947篇
  2022年   1871篇
  2021年   2470篇
  2020年   2511篇
  2019年   2005篇
  2018年   1921篇
  2017年   1877篇
  2016年   2041篇
  2015年   2186篇
  2014年   3571篇
  2013年   4058篇
  2012年   3538篇
  2011年   3631篇
  2010年   2588篇
  2009年   2409篇
  2008年   2297篇
  2007年   2318篇
  2006年   2251篇
  2005年   1960篇
  2004年   1633篇
  2003年   1394篇
  2002年   1007篇
  2001年   909篇
  2000年   755篇
  1999年   695篇
  1998年   562篇
  1997年   519篇
  1996年   451篇
  1995年   432篇
  1994年   403篇
  1993年   344篇
  1992年   310篇
  1991年   284篇
  1990年   208篇
  1989年   214篇
  1988年   170篇
  1987年   135篇
  1986年   106篇
  1985年   142篇
  1984年   85篇
  1983年   68篇
  1982年   83篇
  1981年   68篇
  1980年   40篇
  1979年   40篇
  1978年   24篇
  1977年   25篇
  1976年   33篇
  1975年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
1275 patients were evaluated for HIV-1+2 seroprevalence and its association with clinical symptoms of HIV infection. Of 667 apparently healthy subjects, 8.2% had anti-HIV-1 antibodies. In 465 patients with clinical signs of AIDS, 39.4% were seropositive. 143 patients with miscellaneous symptoms had positive predictive values for HIV infection between 67% (vaginal ulcerations) and 20% (profound pyogenic abscesses). The WHO definition for AIDS had a specificity of 78.3%, a sensitivity of 72.2% and a predictive value of 61.6%.  相似文献   
52.
研究背景 轮状病毒性胃肠炎是婴幼儿期最常见腹泻疾病之一。国内外对轮状病毒中枢神经及肺部感染告道甚少。 研究方法 用电镜、免疫电镜、酶联免疫吸附与阻断试验确诊轮状病毒中枢神经及肺部感染。 研究结果 200例轮状病毒性胃肠炎患儿中,并发轮状病毒性脑膜炎一例,轮状病毒性肺炎2例,其中1例同时合并胸膜炎、胸腔积液。 结论 轮状病毒中枢神经及肺部感染预后良好。  相似文献   
53.
目的评价床边纤维支气管镜检查在可疑院内获得性肺炎诊断中的意义。方法对25例可疑院内获得性肺炎患者进行床边纤维支气管镜检查,同时进行痰标本和支气管肺泡灌洗液标本涂片细菌检测和培养。结果1例为肺出血,2例肺不张,1例肺水肿;21例为院内获得性肺炎,其中14例(72.7%)细菌培养阳性,革兰阴性杆菌占57.1%(12/21),以铜绿假单胞菌、不动杆菌属、嗜麦芽假单胞菌、肺炎克雷伯菌最常见,革兰阳性球菌2例(9.5%),主要是耐甲氧西林金黄色葡萄球菌。痰涂片和支气管肺泡灌洗液涂片阳性者分别为3例和10例。支气管肺泡灌洗液细菌涂片阳性率和细菌培养阳性率均高于痰标本(P=0.02和P=0.005)。结论床边纤维支气管镜检查有助除外疑似院内获得性肺炎的非感染性疾病。支气管肺泡灌洗液标本病原学检测优于痰标本。  相似文献   
54.
腰椎间盘术后椎间盘炎的诊治   总被引:1,自引:1,他引:0  
王义生 《广东医学》1998,19(6):415-417
目的:探讨腰椎间盘术后椎间盘炎的病因。早期诊断和治疗问题。方法:分析10例术后腰椎间盘炎的临床表现、血象、血流变化、血和病灶细菌培养、腰椎X线平片、CT、MRI所见在发病后的敏感程度,比较3例非手术与7例经前路腹膜后(2例联合后入路)病灶清除,一期椎间植骨融合本治疗的效果。结果:不同程度的发热、痉挛性腰痛、血流增快是本病的特点。MRI、CF、X线片三者的诊断敏感性存在时间差,分别约为发病后1、3、5周。仅2例血和病灶细菌培养均阳性。前路减压植骨融合术减少全身性抗生素和镇痛剂的使用量,明显缩短病程。结论:ESR、MRI对早期确诊、引导手术价值较高。高热、痉挛性腰痛、血沉增快三者具一持续2周得不到控制,可考虑及早手术。手术疗法近期效果更为确切。  相似文献   
55.
Under laboratory conditions, various studies have shown that changes in immunological parameters must be expected after exposure to ultraviolet (UV) light. The objective of the present study was to evaluate, whether such changes can also be revealed after a vacation to a sunny country without prior adaptation to ultraviolet radiation. In 32 volunteers white blood cells, lymphocyte subpopulations, sIL2-R, sCD14, immunoglobulins and complement factor C3 were determined before and after a vacation in a country with abundant sunshine during winter. The subjects received relevant doses of UVB as confirmed by questionnaires, UVB-dosimetry and the significant increase of 25-hydroxyvitamin D. After vacation, there was a significant decrease of the CD4/8 ratio and the serum concentration of IgG. The serum concentration of sIL2-R, sCD14, IgA and C3 was increased after the journey. Sunshine exposure without prior adaptation may be responsible for significant alterations in the immune system in association with a vacation during winter.  相似文献   
56.
Abstract Immunological data have been suggested to be a potential tool in the diagnosis, classification and monitoring of periodontal diseases. However, the role of circulating antibodies in periodontal patients is poorly understood. Patients suffering from localized juvenile periodontitis (LJP) are often reported to show high titers of serum IgG antibodies against Aetinobaeillus actinomycetemcomitans (A. actinomycetemcotnitans), but several affected patients do not. Most studies use well-known reference strains of the bacterium for testing against the patients' sera. The aim of the present investigation was to study the relationship between serum IgG antibody levels to autologous A. actinomycetemcomitans strains and clinical attachment loss (CAL). In addition, we wanted to assess the patients’serum titers against 4 well-known reference strains of the bacterium as well as their general potential immunoglobulin response. Intravenous blood samples were taken from 23 LJP patients and 10 healthy individuals, and autologous A. actinomycetemcomitans strains were cultured from 18 of the L.JP patients. CAL was measured at 4 different sites around ail present teeth and assessed as a % of teeth with at least 1 site moderately ≥2<5 mm) or severely (≥5 mm) involved. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the serum titers of IgG antibodies to A. actinomycetemcomitans antigens. No significant correlation was found between serum IgG antibody titers to autologous strains and CAL. However, there was a trend that low responders had more moderately affected teeth than had high responders and patients with undetectable A. actinomycetemcomitans levels, which is in agreement with a hypothetically protective role of the antibodies. The total counts of immunoglobulin assessed in all participants showed that the predominant class was IgG and the reference group displayed significantly less (p<0.05) IgG and IgG1 counts than the LJP patients. Both the reaction pattern against reference and autologous strains varied widely. We conclude that the specific antibody response against A. actinomycetemcomitans shows a weak correlation to clinical attachment levels in LJP patients.  相似文献   
57.
58.
Skin infection in a man immunosuppressed by corticosteroid treatment was found to be due to Pseudallescheria boydii. Although treatment is often unsatisfactory, infection in this patient responded well to oral ketoconazole and topical miconazole.  相似文献   
59.
肿瘤患者医院感染的分析与预防措施   总被引:7,自引:2,他引:5  
目的了解肿瘤科医院感染特点,为临床减少肿瘤患者感染提供参考信息。方法以主动监测与系统回顾相结合的方法,对2005年全年入住肿瘤科2 679例患者的临床资料进行统计、分析、评定。结果2 679例肿瘤患者发生医院感染120例次,医院例次感染率为4.47%,其中感染1次者179例、2次者31例、≥3次者10例;以呼吸道感染占首位,其中上呼吸道38例、下呼吸道36例,其次为消化道10例、血液9例、手术切口感染8例、泌尿道6例和其他部位感染13例。结论提高机体免疫力、控制内源性感染,是预防与控制肿瘤患者感染的主要措施。  相似文献   
60.
Summary The surfaces of 32 encrusted urinary catheters were examined by scanning electron microscopy to investigate the association of bacteria with the encrusting deposits. Deposits consisted of struvite crystals surrounded by aggregates of very small crystallites of hydroxyapatite. Underneath these minerals there was a layer of closely packed bacteria. Impressions of bacteria were also observed in hydroxyapatite. Crystals were often engulfed by the bacterial layer, which thus appeared to bind the crystals to each other and to the catheter surface. This thick layer of bacteria associated with crystals may protect both the bacteria from antibiotics and the crystals from acidic bladder washout solutions intended to dissolve them. Furthermore, the existence of this sessile population explains why urease-producing bacteria are not invariably detected in the urine of patients with encrusted catheters. The observation of this bacterial layer (or biofilm) by scanning electron microscopy provided direct evidence for infection being implicated in catheter encrustation.  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