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   4491篇
  免费   333篇
  国内免费   37篇
耳鼻咽喉   7篇
儿科学   222篇
妇产科学   53篇
基础医学   647篇
口腔科学   24篇
临床医学   304篇
内科学   800篇
皮肤病学   55篇
神经病学   64篇
特种医学   13篇
外科学   145篇
综合类   173篇
现状与发展   1篇
一般理论   1篇
预防医学   1916篇
眼科学   15篇
药学   185篇
  2篇
中国医学   3篇
肿瘤学   231篇
  2024年   7篇
  2023年   221篇
  2022年   198篇
  2021年   343篇
  2020年   222篇
  2019年   224篇
  2018年   226篇
  2017年   184篇
  2016年   205篇
  2015年   201篇
  2014年   271篇
  2013年   337篇
  2012年   225篇
  2011年   240篇
  2010年   212篇
  2009年   209篇
  2008年   154篇
  2007年   153篇
  2006年   110篇
  2005年   118篇
  2004年   120篇
  2003年   86篇
  2002年   84篇
  2001年   77篇
  2000年   69篇
  1999年   49篇
  1998年   34篇
  1997年   35篇
  1996年   38篇
  1995年   20篇
  1994年   25篇
  1993年   17篇
  1992年   21篇
  1991年   14篇
  1990年   9篇
  1989年   14篇
  1988年   11篇
  1987年   10篇
  1986年   14篇
  1985年   12篇
  1984年   9篇
  1983年   6篇
  1982年   7篇
  1981年   3篇
  1980年   2篇
  1979年   5篇
  1978年   5篇
  1976年   1篇
  1975年   1篇
  1972年   2篇
排序方式: 共有4861条查询结果,搜索用时 15 毫秒
71.
目的:进一步研究树突状细胞与肿瘤细胞的融合瘤苗细胞主动免疫诱导体内抗肿瘤免疫反应及对荷瘤小鼠的免疫治疗效果。方法:直接分离骨髓树突状细胞和体外生长因子诱导扩增培养相结合,获得大量高纯度的树突状细胞,再以500g/LPEG诱导其与NS1骨髓细胞融合,HAT选择培养得到两者的融合细胞,体外进行混合淋巴细胞培养,并进行免疫预防与治疗的在体动物实验。结果:融合细胞也能诱导淋巴细胞的增殖反应,而NS1无此作用。体内免疫预防试验表明,融合细胞活瘤苗1次免疫后,诱导出较强的细胞毒性T淋巴细胞(CTL),并获得抵抗野生型NS1攻击的保护性反应,但对无关瘤株则无此抵抗力。融合细胞对荷瘤小鼠的免疫治疗试验显示,融合细胞静脉注射后,能够明显抑制肿瘤生长,延长其生存期。结论:树突状细胞与肿瘤细胞融合后的瘤苗体内免疫,能有效地诱导抗肿瘤免疫反应,可望成为肿瘤免疫预防和免疫治疗的新途径。  相似文献   
72.
Poliomyelitis caused by polioviruses has already been eradicated from industrialized countries of North America, Europe, Asia and Oceania, but the procedures by which this eradication was achieved are not adequate for the poor tropical and subtropical countries. The major challenge now is first to eliminate it rapidly from Asia and Africa where an estimated 250,000 cases and 25,000 deaths currently occur annually. The great progress toward eradication of wild polioviruses from poor tropical and subtropical countries in Latin America was achieved not by the procedures still recommended by the WHO Expanded Program on Immunization (EPI) but by the independently organized annual, national days of antipolio vaccination — all based on the use of large armies of well-trained non-professional, community volunteers — first used in Cuba (1962), Brazil (1980), Nicaragua (1981), Dominican Republic (1983), Paraguay (1985), and Mexico (1986). This novel approach, described in some detail in this communication, is recommended for the rapid elimination of wild polioviruses from Asia and Africa, and for ultimate global eradication with the help of a special cadre within the EPI of WHO. The extensive use by the Pan American Health Organization (PAHO) of highly sophisticated regional virus laboratories has led to the recognition that, in areas from which poliomyelitis caused by polioviruses has been largely eliminated, there are thousands of cases of acute flaccid paralysis, previously clinically diagnosed as probable poliomyelitis, that have no viral etiology, a phenomenon previously reported by Dr. Manuel Ramos Alvarez in Mexico City in 1967.  相似文献   
73.
Summary The feasibility of using a vaccine against luteinizing-hormone-releasing factor for supression of pituitary and gonadal functions has been indicated for some time. Antibody production against this low-molecular-weight, naturally occurring decapeptide, however, requires to be coupled to a carrier protein to enhance its immunogenicity. LHRH was coupled to diphtheria toxoid (DT). Adult male Sprague-Dawley rats with a mean basal body weight of 200g were immunized with anti-LHRH-DT (20 g/injection/rat) at four-week intervals. An equal number of unexposed animals served as controls. Six animals were killed every two weeks up the end of the week 43. The vaccination schedule did not have any effect on the gain in body weight, nor was any adverse effect of vaccination observed in the course of the investigations. The pituitary, prostate, epididymis, testes, seminal vesicles, adrenal and thyroid were excised for determination of organ weight and histological examination. The adrenal, pituitary and thyroid showed no remarkable weight changes during the observation period, whereas the weights of the reproductive organs demonstrated significant reductions compared to those of the control group. The histopathology revealed marked to significant changes in the gonads and the accessory sex organs including the prostate. A progressive phase of regeneration of spermatogenesis was evident 98 days after vaccination. Total recovery of spermatogenesis was observed 300 days after vaccination. The mating studies showed the return of fertility 300 days after vaccination. The litters borne were normal. Prostate showed recovery after 154 days of vaccination. Our observations lend strong support to the hypothesis that anti-LHRH vaccine can be effectively used on the management of prostate carcinoma. If the vaccination is given together with a suitable dose of long-acting androgen, contained in an adequate delivery system, the regimen may be used for the regulation of male fertility.  相似文献   
74.
BACKGROUND: Streptococcus pneumoniae, a common pathogen leading to pneumonia, is a cause of morbidity and mortality in immunosuppressed patients. Vaccination against this agent can be recommended for immunosuppressed patients, including those with chronic renal failure, nephrotic syndrome and renal transplant recipients; however, a diminished immune response and loss of protective antibodies have been observed. PATIENTS AND METHODS: In our prospective study, the efficacy and side effects of polyvalent pneumococcal vaccination were investigated in renal transplant recipients. A total of 21 patients (6 female, 15 male) with well-functioning renal allografts, who had transplant surgery at least 2 months before, were included in the study. The patients were stratified according to the immunosuppressive protocol and 8 received double, while 13 received triple, immunosuppressive agents. After obtaining basal serum samples, all cases were vaccinated with the 0.5 mL intramuscular administration of polyvalent polysaccharide pneumococcal vaccine (Pneumo 23 Pasteur Merieux, lot No: K 1131). RESULTS: Following a mean of 6 wk in all patients and also a mean of 12 wk in 12 patients, serum samples were again obtained to measure pneumococcal antibodies. Antibody titers following 6 and 12 wk of vaccination were significantly higher, as compared with basal values in all patients, except one. These titers did not show any statistically significant difference between double and triple therapies. There was no significant difference between the 12th and 6th wk postvaccination antibody titers. No systemic or local adverse effects were observed. CONCLUSION: Pneumococcal vaccination is safe and effective in patients with well-functioning renal allografts, at least in the short term. This vaccination policy may be useful for preventing invasive pneumococcal disease in immunosuppressed patients.  相似文献   
75.
河南省1963~2002年百日咳流行动态及控制策略分析   总被引:8,自引:0,他引:8  
目的掌握河南省40年来百日咳的流行病学特征及其影响因素,为制定免疫策略和预测疫情趋势提供依据。方法对河南省不同免疫阶段的百日咳流行病学特征进行分析。结果河南省40年来共报告百日咳3 065 075例,死亡572例。大致可分4个阶段:1963~1978年,年平均发病率为293.47/10万,死亡43例;1979~1983年,年发病率为87.70/10万~17.78/10万,呈逐年下降趋势,死亡6例;1984~1990年,发病率为1.28/10万~6.73/10万,死亡1例;1990年以后发病率为0.25/10万~1.00/10万,连续10年无死亡病例。表明随着百日咳疫苗接种率的不断提高,不但大大降低了百日咳的发病率和死亡率,也改变了其流行周期。结论目前的免疫策略首先应继续做好儿童常规免疫,其次应加强百日咳疫情管理,提高疫情报告的及时性、准确性。  相似文献   
76.
Laurent Coudeville  MD  PhD    Alain Brunot  MD  PhD    Thomas D. Szucs  MD  MBA  MPH    Benoit Dervaux  PhD 《Value in health》2005,8(3):209-222
OBJECTIVE: To determine the economic impact of childhood varicella vaccination in France and Germany. METHODS: A common methodology based on the use of a varicella transmission model was used for the two countries. Cost data (2002 per thousand) were derived from two previous studies. The analysis focused on a routine vaccination program for which three different coverage rates (CRs) were considered (90%, 70%, and 45%). Catch-up strategies were also analyzed. A societal perspective including both direct and indirect costs and a third-party payer perspective were considered (Social Security in France and Sickness Funds in Germany). RESULTS: A routine vaccination program has a clear positive impact on varicella-related morbidity in both countries. With a 90% CR, the number of varicella-related deaths was reduced by 87% in Germany and by 84% in France. In addition, with a CR of 90%, routine varicella vaccination induces savings in both countries from both societal (Germany 61%, France 60%) and third-party payer perspectives (Germany 51%, France 6.7%). For lower CRs, routine vaccination remains cost saving from a third-party payer perspective in Germany but not in France, where it is nevertheless cost-effective (cost per life-year gained of 6521 per thousand in the base case with a 45% CR). CONCLUSION: Considering the impact of vaccination on varicella morbidity and costs, a routine varicella vaccination program appears to be cost saving in Germany and France from both a societal and a third-party payer perspective. For France, routine varicella vaccination remains cost-effective in worst cases when a third-party payer perspective is adopted. Catch-up programs provide additional savings.  相似文献   
77.
新兵甲肝和乙肝疫苗联合免疫效果及安全性的对照研究   总被引:1,自引:0,他引:1  
目的探讨新兵联合接种甲肝疫苗和乙肝疫苗的免疫效果及安全性。方法200名健康新兵随机均分为4组。A组:于0、6个月接种2剂甲肝减毒活疫苗,B组:于0、1、6个月接种3剂乙肝疫苗,C组:一侧上臂于0、6个月接种2剂甲肝减毒活疫苗,另一侧上臂于0、1、6个月接种3剂乙肝疫苗,D组:于0、6个月接种2剂甲、乙型肝炎联合疫苗。于首针后7个月时测定甲肝和乙肝抗体滴度,观察免疫效果和安全性。结果甲肝和乙肝疫苗双上臂同时接种,抗-HAV和抗-HBs的阳转率分别是100%和91.84%,与各自单独接种的免疫效果无显著性差异;按0、6个月2剂免疫程序接种甲、乙型肝炎联合疫苗,抗-HAV和抗-HBs的阳转率分别是100%和92.5%,与各自单独接种的免疫效果亦无显著性差异。结论新兵同时接种甲肝和乙肝疫苗安全、有效,若经济条件允许则可接种甲、乙型肝炎联合疫苗。  相似文献   
78.
目的 了解影响成人疫苗接种率的有关社会经济影响因素。方法 选择广西河池市2个城镇,对5~60岁登记在册居民按有对照的组群随机抽样原则进行伤寒Vi疫苗和A群流脑疫苗的大规模接种;比较接种者的人口学和社会经济特征与接种率的关系。结果 应接种对象118071人,实际接种92476人,接种率为78.32%,其中伤寒Vi疫苗76.87%;流脑疫苗79.69%。城市接种率为77.29%,农村接种率为80.58%;5~9岁接种率最高,为89.65%;20~29岁组最低,仅为69.07%;男女接种率分别为79.07%和82.11%;高收入住户人群接种率最高达到90%左右;18~60岁人群中,按受教育程度分析以“小学毕业”人群接种率最高,为78.34%;按居住单元分析,学生的人群接种率最高,达92.01%,私营业主和退休人群接种率最低,分别为69.71%和68.82%;居住未满1年者的人群接种率最低.为62.5%.居住1~2年者接种率最高,为84.47%。结论 受教育程度、经济收入、居住年限以及城乡差别对接种率并无直接影响;流动性大、老年人是影响疫苗接种率的主要因素。  相似文献   
79.
目的研究伤寒Vi多糖菌苗免疫后长期效果。方法现场实验流行病学。结果接种后伤寒Vi多糖菌苗1~3年的有一定的保护作用,且在这3年中保护效果无差别。结论接种伤寒Vi多糖菌苗是今后预防伤寒的重要措施之一,但不必要每年均接种。  相似文献   
80.
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