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   22754篇
  免费   1403篇
  国内免费   946篇
耳鼻咽喉   81篇
儿科学   383篇
妇产科学   181篇
基础医学   1300篇
口腔科学   333篇
临床医学   1526篇
内科学   2081篇
皮肤病学   169篇
神经病学   1174篇
特种医学   451篇
外国民族医学   8篇
外科学   1419篇
综合类   3195篇
现状与发展   2篇
一般理论   1篇
预防医学   2407篇
眼科学   372篇
药学   5864篇
  18篇
中国医学   2205篇
肿瘤学   1933篇
  2024年   73篇
  2023年   434篇
  2022年   676篇
  2021年   860篇
  2020年   809篇
  2019年   703篇
  2018年   669篇
  2017年   772篇
  2016年   761篇
  2015年   670篇
  2014年   1199篇
  2013年   1979篇
  2012年   1217篇
  2011年   1344篇
  2010年   1130篇
  2009年   1124篇
  2008年   1137篇
  2007年   1196篇
  2006年   1036篇
  2005年   895篇
  2004年   742篇
  2003年   627篇
  2002年   529篇
  2001年   480篇
  2000年   387篇
  1999年   358篇
  1998年   337篇
  1997年   333篇
  1996年   271篇
  1995年   244篇
  1994年   257篇
  1993年   222篇
  1992年   174篇
  1991年   155篇
  1990年   152篇
  1989年   145篇
  1988年   145篇
  1987年   82篇
  1986年   74篇
  1985年   136篇
  1984年   112篇
  1983年   100篇
  1982年   90篇
  1981年   51篇
  1980年   56篇
  1979年   23篇
  1978年   38篇
  1977年   18篇
  1976年   33篇
  1975年   19篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
It is known that approximately 10% of successful quitters relapse annually. This study aimed to investigate the factors related to long-term smoking relapse in individuals who succeeded in maintaining smoking cessation for 6 months after attending a regional smoking cessation program.This study enrolled 943 individuals registered for the regional smoking cessation program at the Busan Smoking Cessation Center in 2018–2019 who maintained smoking cessation for 6 months. A survey was conducted using a smartphone link or through phone calls, and the data for 305 participants who finally completed the survey were analyzed. The questionnaire addressed individual, inter-individual, organizational, and community-level factors related to smoking relapse. Multivariate logistic regression analysis was performed to evaluate the factors associated with smoking relapse by period. The Cox proportional hazard regression model was used for the factors associated with smoking relapse for the entire period.The smoking relapse rate at the time of the survey was 25.4%. In the analysis of smoking relapse by period, relapse was associated with the belief that smoking relieves stress, the number of single-person households, and poor subjective health status. In the analysis of smoking relapse during the entire period, we observed a significant association with the belief that smoking relieves stress (hazard ratio [HR]: 2.65, 95% confidence interval [CI]: 1.52–4.61), single-person households (HR: 1.95, 95% CI: 1.16–3.26), and high levels of emotional stress (HR: 1.72, 95% CI: 1.04–2.85).Long-term follow-up is necessary to prevent smoking relapse in single-person households, individuals who believe that smoking relieves stress, and those experiencing high levels of subjective emotional stress. Interventional therapies for stress relief and awareness improvement in smokers need to be developed.  相似文献   
82.
目的观察动物口服六味银杏胶囊的急性毒性和长期毒性反应。方法采用最大给药量法测定小鼠口服六味银杏胶囊的急性毒性;以20.0,10.0,5.0 g生药.kg-1.d-13个剂量的六味银杏胶囊(相当于临床用量68、34、17倍)灌胃SD大鼠,连续24周,观察服药24周及停药4周后,大鼠的生长发育、血液学、血液生化学、组织病理指标的变化。结果小鼠1天内口服六味银杏胶囊最大给药量为190.0 g生药/kg,相当于临床用量的700倍。长期毒性实验中,各剂量组与空白对照组比较,大鼠一般状况,体重增长,血液学、血液生化指标,主要脏器系数,肉眼观察及镜下组织形态学观察均无明显差异或异常。结论六味银杏胶囊临床用药范围内应用是比较安全的。  相似文献   
83.
In recent years, numerous atypical Bluetongue virus (BTV) strains have been discovered all around the world. Atypical BTV strains are phylogenetically distinct from the classical BTV serotypes 1–24 and differ in terms of several biological features. For the first time, the atypical strains BTV-25-GER2018 and BTV-33-MNG3/2016 as well as the re-emerged classical strain BTV-8-GER2018 were evaluated comparatively in a pathogenesis study in goats—the natural host of atypical BTV. A substantial number of in-contact animals were included in this study to detect potential contact transmissions of the virus. After infection, EDTA blood, ocular, nasal and oral swab samples as well as serum were collected regularly and were used for virological and serological analyses, respectively. Our study showed differences in the immunological reaction between the two atypical BTV strains (no group-specific antibody detection) and the classical BTV strain BTV-8-GER2018 (group-specific antibody detection). Furthermore, we observed an increase in the total WBC count (neutrophils and lymphocytes) in goats infected with the atypical BTV strains. No horizontal transmission was seen for all three strains. Our study suggests that the atypical BTVs used in the trial differ from classical BTVs in their immunopathogenesis. However, no evidence of direct contact transmission was found.  相似文献   
84.
Aims/IntroductionGlucagon‐like peptide‐1 receptor agonists (GLP‐1 RA) might be less effective in patients with severe hyperglycemia, because hyperglycemia downregulated the GLP‐1 receptor in an animal study. To examine this hypothesis clinically, we compared the glucose‐lowering effects of GLP‐1 receptor agonist liraglutide with and without prior glycemic control.Materials and MethodsIn an open‐label, parallel trial, participants with poorly controlled type 2 diabetes were recruited and randomized to receive once‐daily insulin therapy, degludec (Insulin–GLP‐1 RA relay group, mean 16.8 ± 11.4 IU/day), for 12 weeks and then liraglutide for 12 weeks or subcutaneous injections of GLP‐1 RA, liraglutide (GLP‐1 RA first group, 0.9 mg), for 24 weeks. The primary efficacy end‐points consisted of changes in the levels of fasting plasma glucose and glycated hemoglobin (HbA1c).ResultsThe median fasting plasma glucose and HbA1c before the study were 210.0 mg/dL and 9.8%, respectively. The levels of fasting plasma glucose and HbA1c significantly decreased in the Insulin–GLP‐1 RA relay group (P < 0.001) and GLP‐1 RA first group (P < 0.001) by week 24, although no intergroup differences were observed. The reduction of HbA1c in the Insulin–GLP‐1 RA relay group tended to be larger than that in the GLP‐1 RA first group in the lowest CPR (C‐peptide immunoreactivity) quartile (P = 0.072). The adverse events consisted of gastrointestinal problems, followed by hypoglycemia.ConclusionsThe GLP‐1 receptor agonist is overall effective without prior glycemic control with insulin in participants with poorly controlled type 2 diabetes. However, in participants with insulinopenic type 2 diabetes, prior glycemic control with insulin might overcome glucose toxicity‐induced GLP‐1 resistance.  相似文献   
85.
As an important water conveying structure, the seismic safety of the hydraulic aqueduct has attracted considerable interest. Different from the general bridge structure, the seismic analysis of the aqueduct structure needs to consider its fluid–structure interaction. The existing numerical simulation methods cannot truly reflect the fluid–solid coupling mechanism. Therefore, scholars began to use shaking table tests to study the fluid–structure interaction mechanism. However, the research is immature, and it is mostly focused on the seismic response analysis, and there are few studies on the model test similarity ratio and model material properties. Based on this, in this paper, according to the requirements of the test similarity ratio, the orthogonal experiment was used to explore the influence of barite sand content, water–cement ratio, fine sand ratio, and lime ratio on the mechanical properties of microconcrete. The performance indicators of microconcrete under different mix ratios vary widely, with a minimum variation of 19% and a maximum of 102%. Barite sand has the most significant control effect on the density, and the water–cement ratio has the most significant control effect on the compressive strength and elastic modulus. The density variation range is 2.37–2.81 g/cm3, the cube compressive strength variation range is 18.37–36.94 MPa, and the elastic modulus variation range is 2.11 × 104–3.28 × 104 MPa. This study will provide certain evidence for the similarity ratio design and material selection of the scaled model test of the fluid–solid coupling structure.  相似文献   
86.
多指标正交试验优选白术芍药散提取工艺   总被引:3,自引:1,他引:3  
白术芍药散是中医传统名方,临床对于腹泻有确切的治疗效果.然而,目前有关白术芍药散的提取工艺报道较少.该试验利用正交试验的方法,以复方中10个指标性成分和浸出物的含量作为指标,采用综合加权评分法处理数据,对提取工艺中乙醇浓度、溶剂倍量、浸泡时间、提取时间4个因素进行考察,以优化白术芍药散提取工艺.结果得出白术芍药散的最佳提取工艺为加入12倍量70%乙醇,浸泡1h,提取2次,每次2h.其中提取时间有显著影响.优化后的提取工艺稳定可靠,可为进一步开发利用该处方提供参考.  相似文献   
87.
医用化学实验课时和教改前相比,有较大幅度的压缩。本文分析了我校医用化学实验课的现状,提出通过在实验课剩余时间插入微型实验的方法,提高实验课教学效率的可能性,并列举实例。  相似文献   
88.
Aim: To clarify the question of whether patients with Kawasaki disease suffer a higher mortality rate after the incidence of the disease in comparison with age-matched healthy individuals. Methods: Between July 1982 and December 1992, 52 collaborating hospitals collected data on all patients having a new, definite diagnosis of Kawasaki disease. Patients were followed up until 31 December 2001 or their death. The expected number of deaths was calculated from Japanese vital statistics data and compared with the observed number. Results: Of 6576 patients enrolled, 29 (20 males and 9 females) died. The standardized mortality ratio (SMR: the observed number of deaths divided by the expected number of deaths based on the vital statistics in Japan) was 1.15 (95% CI: 0.77-1.66). In spite of the high SMRs during the acute phase, the mortality rate was not high after the acute phase for the entire group of patients. Although the SMR after the acute phase was 0.75 for those without cardiac sequelae, six males (but none of the females) with cardiac sequelae died during this period; and the SMR for the male group with cardiac sequelae was 1.95 (95% CI: 0.71-4.25). The mortality from congenital anomalies of the circulatory system was elevated, but no increase in cancer deaths was observed.

Conclusion: Although it was not statistically significant, the mortality rate among males with cardiac sequelae due to Kawasaki disease appeared to be higher than in the general population. On the other hand, the mortality rates for females with the sequelae and both males and females without sequelae were not elevated.  相似文献   
89.
目的:在器官发生期对怀孕大鼠连续给予甲磺酸胺银杏内酯B,观察是否有母体毒性和胚胎毒性。方法:甲磺酸胺银杏内酯B以250、125、62.5mg&#183;k^-1于妊娠第6~15天连续口服灌胃给药,观察孕鼠饮水、摄食、生长等一般状况。每周称重2次,妊娠第20天处死孕鼠,记录黄体数、胎盘重、着床数、死胎数、活胎数、胎仔性别及体重等,观察活仔外观异常。各窝1/2胎仔作骨骼畸形检查,另1/2胎仔作内脏检查。结果:甲磺酸胺银杏内酯B原料高、中、低剂量用药组,母体未出现临床中毒症状,但高剂量甲磺酸胺银杏内酯B组后期体重增加幅度明显低于溶剂对照组。高、中剂量组的着床总数、活胎数、吸收胎数、子宫总重、胎盘总重、黄体数、胎鼠顶臀长、胎鼠体重等与对照组相比有明显差异,低剂量组的各项指标未见统计学差异。高、中剂量组的骨骼畸形也较对照组明显增多,而低剂量组与溶剂对照组相比无显著差异。结论:对母体一般状况和子代发育均安全的剂量为62.5mg&#183;kg^-1。  相似文献   
90.
附子毒-效关系探析   总被引:2,自引:0,他引:2  
李琳  平静 《河南中医》2015,35(1):171-172
应用附子要以"得附子之益,去附子之损"为原则,正所谓"正有毒以祛毒,非无毒以治有毒也"。附子之毒与效密不可分,是以毒攻毒治法的具体体现,辨证地看待附子的毒-效关系,从而对今后附子的临床合理应用提供一定的借鉴。  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