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   85515篇
  免费   6566篇
  国内免费   3462篇
耳鼻咽喉   994篇
儿科学   1372篇
妇产科学   2415篇
基础医学   10603篇
口腔科学   1480篇
临床医学   9801篇
内科学   15158篇
皮肤病学   1438篇
神经病学   4999篇
特种医学   3361篇
外国民族医学   22篇
外科学   10686篇
综合类   8108篇
现状与发展   10篇
一般理论   12篇
预防医学   4746篇
眼科学   2109篇
药学   7756篇
  44篇
中国医学   2820篇
肿瘤学   7609篇
  2024年   165篇
  2023年   890篇
  2022年   2324篇
  2021年   3293篇
  2020年   2171篇
  2019年   2278篇
  2018年   2723篇
  2017年   2257篇
  2016年   2239篇
  2015年   3372篇
  2014年   4181篇
  2013年   4490篇
  2012年   6473篇
  2011年   6436篇
  2010年   4062篇
  2009年   3421篇
  2008年   4653篇
  2007年   4611篇
  2006年   4515篇
  2005年   4093篇
  2004年   3553篇
  2003年   3397篇
  2002年   2957篇
  2001年   2328篇
  2000年   2173篇
  1999年   1887篇
  1998年   923篇
  1997年   770篇
  1996年   644篇
  1995年   601篇
  1994年   564篇
  1993年   360篇
  1992年   857篇
  1991年   728篇
  1990年   624篇
  1989年   584篇
  1988年   502篇
  1987年   512篇
  1986年   420篇
  1985年   336篇
  1984年   271篇
  1983年   219篇
  1982年   133篇
  1981年   132篇
  1980年   105篇
  1979年   217篇
  1978年   161篇
  1977年   103篇
  1976年   110篇
  1975年   102篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
国人C型肝性脑病发病诱因分析   总被引:1,自引:0,他引:1  
曾峥 《中国医药》2007,2(10):579-581
目的了解国人C型肝性脑病发病诱因及相关因素。方法对国内已经发表的11个研究样本(患者总样本量1131例)进行综合分析。结果在9类纳入统计分析的诱因中:消化道出血占43.8%、各种感染占33.9%、电解质紊乱占29.1%、医源性因素占28.2%、饮食不节占14.2%、肾功能衰竭占13.0%,分居前6位,另外腹泻占2.4%,便秘占1.8%,原因未明/无占2.7%。其中医源性因素按照发生频率依次为:大量利尿和/或放腹水占14.5%、手术/创伤占6.0%,药物占4.5%,输血/输复合氨基酸占3.2%。结论警惕肝性脑病多种诱因的存在,尤其不能忽视医源性因素。按照发病概率积极寻找并消除诱因,对于改善顸后尤为重要。  相似文献   
72.
LHRH-PE40识别结肠癌细胞膜表面蛋白的研究   总被引:1,自引:0,他引:1  
目的探讨人结肠癌细胞系Lovo及人白血病细胞系Jurket细胞膜表面蛋白能否识别LHRH-PE40及是否存在竞争性抑制。方法将结肠癌细胞系Lovo及白血病细胞系Jurket制备成细胞膜,利用125I标记的LHRH-PE40与两种细胞膜进行放射性配基分析,与LHRH进行竞争结合分析。结果人结肠癌细胞系Lovo的结合竞争符合特异性配基-受体结合、竞争;而白血病细胞系Jurket未见配基-受体特异性结合。其中LHRH-PE40与Lovo细胞的亲和力:Kd=10·6±2·33nmol/L,容量Bmax=345±7·59pmol/mg。结论LHRH是结肠癌免疫治疗的有效靶点,LHRH-PE40对过度表达LHRH受体的结肠癌具有特异性杀伤作用,而对无LHRH表达的肿瘤无杀伤作用,对于药物的临床应用有着指导意义。  相似文献   
73.
74.
本文对1984年1~3月和1985年3~8月共107例急性下呼吸道感染的住院患儿,采用间接免疫荧光法检测其急性期血清抗RSV特异性IgM抗体,并与病毒分离和/或中和试验比较,敏感性为82.1%,特异性为71.8%。RSV感染患儿发病后3天内大多数病例即可从血清中检测出RSV-IgM,因此该法具有早期诊断价值。  相似文献   
75.
Sixty strains of Riemerella anatipestifer were isolated from ducks and geese with infectious serositis in Taiwan. Sixty per cent of the isolates (36/60) contained a 3.9 b plasmid, 12% (7/60) contained 6.5 b and 16 b plasmids, 5% (3/60) contained 2.9, 16 and 18 b plasmids and 13% contained no plasmid (14/60). The 3.9 b plasmid (designated as pCFC1) was completely sequenced to determine if it encoded virulence factors. pCFC1 was 27% G-C and had four large open reading frames (ORF). Two of the ORFs (designated as VapD1 and VapD2) encoded proteins that shared 80, 83, 69 and 67 (VapD1) and 50, 48, 21 and 20% (VapD2) identity with virulence-associated proteins of Actinobacillus Actinomycetemcomitans, Dichelobcater nodosus, Haemophilus influenzae and Neisseria gonorrheae, respectively. pCFC1 also had an ORF (designated as RepAl) that encoded a protein with approximately 30% identity to the RepA proteins of Neisseria gonorrhoeae, Campylobactor hyointestinalis and Pseudomonas aeroginosa. The region upstream of the RepA ORF had an A-T-rich region that was followed by four 21 bp perfect and one 20 bp imperfect direct repeat. The fourth ORF (designated as RepA2) encoded a protein with a region that was 44% homologous to the Helicobactor pylori replication protein.  相似文献   
76.
Antigenic characterization of urothelial cells cultured from normal adult ureter was performed. These cells were cultured using a simplified isolation and culture technique and a commercially available serum-free medium. The cells growing in these cultures had epithelioid morphology and normal quantities of DNA. The antigen expression on these cultured normal urothelial cells was evaluated using a panel of monoclonal antibodies: 5G6.4, AN43, URO-5, anti-keratin and anti-blood group antibodies, and 425 (anti-epidermal growth factor receptor). Lower levels of anti-A and AN43 binding on cultured cells were observed than are seen on urothelial cells in sections of normal ureter, while the binding of anti-blood group H, 5G6.4, and URO-5 was unchanged. Binding of anti-epidermal growth factor receptor antibody 425 was improved if the cells were grown in medium lacking epidermal growth factor. These results confirm the urothelial origin of these cultured urothelial cells but indicate that some antigenic differences between cultured normal urothelial cells and urothelial cells in situ in the normal ureter exist.  相似文献   
77.
本文报告谷参肠安胶囊大鼠长期毒性试验,结果表明,谷参肠安胶囊对动物的一般状况,体重增长、外周血象、肝肾功能及病理组织学检查等未见明显毒性。  相似文献   
78.
Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood lead levels in lead battery factories. Received: 28 May 1996/Accepted: 30 August 1996  相似文献   
79.
Human bladder cancer cell lines, J82, Yen-87, Shen-87 and Zoa-88, and murine bladder cancer cell lines, MBT-2 and M1660, were used as target cells for dye-sensitized photoinactivation study in using methylene blue. Normal fibroblast cells, FB-1 and FB8490, were used as control group. The cytoplasmic activity of lactic dehydrogenase, soft agar clonogenic assay, and in vivo tumor growth, survival rate and tumor taking rate with or without photoinactivation were monitored and compared between different cell lines. Efficacy of photoinactivation was time-related and more than 90 per cent of cytotoxicity could be obtained within 60 minutes of illumination. The plateau of cytotoxicity curve could be achieved after staining for 30 minutes by methylene blue under the same illumination time. Normal fibroblasts had the same features with cancer cells. Photoinactivation of tumor cells showed significant inhibition of tumor growth and tumor taking rate in experimental animals. Survival rate was also significantly prolonged in the animals with tumor cells receiving photoinactivation. These results suggest that methylene blue-sensitized photoinactivation may be useful as an adjuvant photochemotherapy for superficial bladder cancer.  相似文献   
80.
Certain features of head-injured patients admitted to the Chang Gung Memorial Hospital in Taiwan during the period 1977 to 1987 were reviewed. The most common causes of injury were motorcycle accidents (56.3%) and street accidents with pedestrian injury (29.47%). The age groups with the greatest incidence of injury were aged 16-20 years, 21-25 years, and 25-30 years. The pedestrian group involving the highest incidence of injury was less than 10 years of age. Overall mortality was 17.26%. The injured pedestrian group had the highest mortality (19.1%). Initial clinical assessment was recorded using the Glasgow Coma Scale. Head-injured patients with a GCS less than 8 had a mortality in the injured pedestrian group of 46%, whereas the mortality rate in the motorcycle accident group was 41%. Additional features studied were time of occurrence of injury and pattern of injury. Information gathered from this study would suggest the need to establish a Head Injury Prevention Program in Taiwan. This of course implies major cooperation among the providers of health care delivery, the medical profession, legislators, and the government at all levels.  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