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   2718篇
  免费   233篇
  国内免费   56篇
耳鼻咽喉   43篇
儿科学   181篇
妇产科学   75篇
基础医学   283篇
口腔科学   82篇
临床医学   212篇
内科学   705篇
皮肤病学   71篇
神经病学   150篇
特种医学   235篇
外科学   387篇
综合类   162篇
预防医学   122篇
眼科学   51篇
药学   109篇
中国医学   10篇
肿瘤学   129篇
  2024年   3篇
  2023年   29篇
  2022年   43篇
  2021年   69篇
  2020年   47篇
  2019年   34篇
  2018年   56篇
  2017年   80篇
  2016年   102篇
  2015年   101篇
  2014年   143篇
  2013年   163篇
  2012年   135篇
  2011年   137篇
  2010年   133篇
  2009年   124篇
  2008年   137篇
  2007年   181篇
  2006年   152篇
  2005年   127篇
  2004年   107篇
  2003年   83篇
  2002年   72篇
  2001年   41篇
  2000年   24篇
  1999年   30篇
  1998年   86篇
  1997年   73篇
  1996年   66篇
  1995年   52篇
  1994年   50篇
  1993年   50篇
  1992年   15篇
  1991年   14篇
  1990年   25篇
  1989年   23篇
  1988年   28篇
  1987年   17篇
  1986年   21篇
  1985年   21篇
  1984年   12篇
  1983年   15篇
  1982年   9篇
  1981年   8篇
  1980年   10篇
  1979年   6篇
  1978年   12篇
  1977年   9篇
  1976年   12篇
  1975年   10篇
排序方式: 共有3007条查询结果,搜索用时 0 毫秒
991.
We have previously reported that Morinda citrifolia (noni) puree modulates neonatal calves developmental maturation of the innate and adaptive immune system. In this study, the effect of noni puree on respiratory and gastrointestinal (GI), health in preweaned dairy calves on a farm with endemic salmonellosis was examined. Two clinical trials were conducted whereby each trial evaluated one processing technique of noni puree. Trials 1 and 2 tested noni versions A and B, respectively. Puree analysis and trial methods were identical to each other, with the calf as the experimental unit. Calves were designated to 1 of 3 treatment groups in each trial and received either: 0, 15 or 30 mL every 12 hr of noni supplement for the first 3 weeks of life. Health scores, weaning age, weight gain from admission to weaning, and weaned by 6 weeks, were used as clinical endpoints for statistical analysis. In trial 1, calves supplemented with 15 mL noni puree of version A every 12 hr had a higher probability of being weaned by 6 weeks of age than control calves (P = 0.04). In trial 2, calves receiving 30 mL of version B every 12 hr had a 54.5% reduction in total medical treatments by 42 days of age when compared to controls (P = 0.02). There was a trend in reduced respiratory (61%), and GI (52%) medical treatments per calf when compared to controls (P = 0.06 and 0.08, respectively). There were no differences in weight gain or mortality for any treatment group in either trial.  相似文献   
992.
993.
994.
Jamieson LM, Roberts‐Thomson KF, Sayers SM. Dental caries risk indicators among Australian Aboriginal young adults. Community Dent Oral Epidemiol 2010; 38: 213–221. © 2009 John Wiley & Sons A/S Abstract – Objectives: To determine dental caries risk indicators among a birth cohort of Australian Aboriginal young adults (n = 442). Methods: Data were from the Aboriginal Birth Cohort study, a prospective longitudinal investigation of Aboriginal individuals born 1987–1990 at an Australian regional hospital. Models representing demographic, socioeconomic, behavioural, dental service utilization and clinical oral health variables were tested using multivariate regression. Results: The percent DT > 0 was 72.9 (95% CI 68.7–77.1), mean DT was 4.19 (95% CI 3.8–4.6), percent DMFT > 0 was 77.4 (95% CI 73.5–81.3) and mean DMFT was 4.84 (95% CI 4.4–5.3). After controlling for other covariates, risk indicators for percent DT > 0 included soft drink consumption every day or a few times a week (PR 1.25, 95% CI 1.08–1.45), not consuming milk every day or a few times a week (PR 1.16, 95% CI 1.04–1.30) and sweet consumption every day or a few times a week (PR 1.18, 95% CI 1.04–1.33). Risk indicators for mean DT included sweet consumption every day or a few times a week (B = 1.14, 95% CI 0.27–2.02), nonownership of a toothbrush (B = 0.91, 95% CI 0.10–1.87) and presence of plaque (B = 2.46, 95% CI 0.96–3.96). Those with 4 + occupants in their house the previous night had 1.2 times the prevalence of having DMFT > 0 than their counterparts with less household occupants (95% CI 1.01–1.49). Percent DMFT > 0 was also associated with consumption of soft drink every day or a few times a week (PR 1.18, 95% CI 1.04–1.34) and consumption of sweets every day or a few times a week (PR 1.23, 95% CI 1.10–1.37). Mean DMFT was higher among those who consumed sweets every day or a few times a week (B = 0.13, 95% CI 0.05–0.22) and who had dental anxiety (B = 0.10, 95% CI 0.01–0.19). Conclusions: In an Australian Aboriginal young adult cohort, risk indicators for dental caries included social determinants such as household size, dietary behaviours such as regular consumption of soft drink and sweets, dental behaviour such as nonownership of a toothbrush and dental anxiety.  相似文献   
995.
Whether plasma exchange would improve survival in antibiotic-treated canines with septic shock was investigated. Escherichia coli O86H8 (1.4 × 10(10)) was surgically implanted as an intraperitoneal clot in 18 two- year-old (10-12 kg) purpose-bred beagles. Beginning 4 hours after surgery, all animals received cefoxitin and gentamicin for 5 days. Three treatment groups were defined: 1) a no apheresis, or control group, (n = 6); 2) a sham apheresis group, whose whole blood plasma was removed, separated, and then transfused (n = 6); and 3) a plasma exchange group from whom blood and plasma were removed and separated, to whom the blood was returned, and in whom infected plasma was replaced with compatible fresh-frozen canine plasma (n = 6). For the sham apheresis and plasma exchange groups, a commercial blood cell processor was used to separate 1.5 blood volumes of plasma at 5 and 24 hours after surgery. Serial radionuclide left ventricular ejection fractions and femoral and pulmonary arterial catheter hemodynamics were measured simultaneously in awake animals. All six animals in the plasma exchange group died. In both the sham and control groups, only one of six animals survived. Survival times were ordered (median in hours) (control [372 h] > sham apheresis [48 h] > plasma exchange [24 h] [p < 0.038]). Decreases in mean cardiac index and mean arterial pressure (from before apheresis to after) at 5 to 7 hours after surgery were ordered (plasma exchange > sham apheresis > control; p < 0.03). Thus, plasma exchange in this controlled trial of septic shock was associated with decreased survival and worsened hemodynamics.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
996.
The effect of combination chemotherapy and cranial irradiation on final height and body proportions was retrospectively examined in a cohort of 142 children treated for acute lymphoblastic leukaemia (ALL). Eighty four children (48 girls, 36 boys) received 24 Gy cranial irradiation and 58 (35 girls, 23 boys) 18 Gy. None had received testicular or spinal irradiation. A significant reduction in standing height SD score from diagnosis to final height was seen in all groups. Of the 109 children in whom sitting height measurements were available, 88 (81%) had relatively shorter backs than legs and in 25 (23%) this disproportion was of a marked degree. After mathematical correction for sitting height loss there was no longer a significant reduction in standing height SD score at final height in all except the 24 Gy group of girls. These data suggest that disproportion is a common finding after treatment for ALL and that, at least in some children, much if not all of the height loss seen is due to a reduction in sitting height. Possible explanations for this disproportion include a disturbance of puberty or an effect of chemotherapy on spinal growth, or both.  相似文献   
997.
A poly(propylene glycol-co-lactide) dimethacrylate adhesive with monocalcium phosphate monohydrate (MCPM)/β-tricalcium phosphate (β-TCP) fillers in various levels has been investigated. Water sorption by the photo-polymerized materials catalyzed varying filler conversion to dicalcium phosphate (DCP). Polymer modulus was found to be enhanced upon raising total calcium phosphate content. With greater DCP levels, faster release of phosphate and calcium ions and improved buffering of polymer degradation products were observed. This could reduce the likelihood of pH-catalyzed bulk degradation and localized acid production and thereby may prevent adverse biological responses. Bone-like MG-63 cells were found to attach, spread and have normal morphology on both the polymer and composite surfaces. Moreover, composites implanted into chick embryo femurs became closely apposed to the host tissue and did not appear to induce adverse immunological reaction. The above results suggest that the new composite materials hold promise as clinical effective bone adhesives.  相似文献   
998.
999.
1000.
BACKGROUND: Choriocarcinoma mostly metastasizes to lung parenchyma. Its pulmonary tumor embolism and cardiac metastasis are very rarely encountered, of which antemortem diagnosis is even more rare. CASE: To our knowledge, we present the first case of intracavitary cardiac metastasis and pulmonary tumor emboli of choriocarcinoma diagnosed and treated without any surgical intervention. Multi-agent chemotherapy led to almost complete regression of cardiac and pulmonary lesions and normalization of beta-hCG levels. CONCLUSION: Cardiac metastasis of choriocarcinoma must be kept in mind for cases of cardiac mass in reproductive age women, especially when history and clinical presentation are suggestive for gestational trophoblastic disease. As the tumor is highly sensitive, chemotherapy together with biochemical and radiological monitoring constitutes an effective treatment modality if cardiopulmonary functions are not deteriorating.  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