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   86014篇
  免费   7931篇
  国内免费   4977篇
耳鼻咽喉   749篇
儿科学   1311篇
妇产科学   1112篇
基础医学   10363篇
口腔科学   1948篇
临床医学   9804篇
内科学   13180篇
皮肤病学   967篇
神经病学   5245篇
特种医学   2997篇
外国民族医学   35篇
外科学   9098篇
综合类   13191篇
现状与发展   18篇
一般理论   10篇
预防医学   6143篇
眼科学   2026篇
药学   9003篇
  85篇
中国医学   4503篇
肿瘤学   7134篇
  2024年   1003篇
  2023年   1449篇
  2022年   2830篇
  2021年   3585篇
  2020年   2824篇
  2019年   2562篇
  2018年   2615篇
  2017年   2533篇
  2016年   2328篇
  2015年   3371篇
  2014年   3939篇
  2013年   3953篇
  2012年   5661篇
  2011年   5852篇
  2010年   3979篇
  2009年   3407篇
  2008年   4196篇
  2007年   4055篇
  2006年   3792篇
  2005年   3336篇
  2004年   2581篇
  2003年   2412篇
  2002年   2034篇
  2001年   3395篇
  2000年   3184篇
  1999年   2769篇
  1998年   1245篇
  1997年   990篇
  1996年   760篇
  1995年   715篇
  1994年   584篇
  1993年   431篇
  1992年   1244篇
  1991年   1102篇
  1990年   959篇
  1989年   1013篇
  1988年   938篇
  1987年   849篇
  1986年   770篇
  1985年   675篇
  1984年   411篇
  1983年   345篇
  1982年   200篇
  1981年   152篇
  1980年   122篇
  1979年   215篇
  1978年   92篇
  1973年   96篇
  1972年   95篇
  1971年   96篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
目的 探讨重症肌无力胸腺切除术后呼吸道管理与并发症的防治.方法 32例ICU收治的重症肌无力胸腺切除术后的患者,根据危象预测积分,分为普通组(积分<12分,n=21)和高危组 (积分>12分,n=11),对两组患者术后呼吸机支持时间、拔管前后肌力恢复情况、自主呼吸情况、动脉血气分析情况以及两组患者术后体温、胸片和痰培养结果进行统计分析.结果 高危组患者术后呼吸支持时间(18 ~ 30 h,平均26 h)大于普通组患者(4 ~ 28 h,平均14 h),两组有显著性差异(P<0.01),同时术后发热、胸片渗出影以及阳性痰培养结果的发生率也高于普通组.结论 术后给予高危患者严密的监测和充分的呼吸支持,有助于降低重症肌无力危象的发生率和死亡率,同时应充分重视气道护理和感染的防治.  相似文献   
82.
目的为了提高对异位妊娠的诊断技术。方法选择在我院经手术病理证实的异位妊娠249例住院患者行2DB超和CDFI的声像图特征进行分析。结果2D超声声像图特征在249例异位妊娠中内膜增厚223例,厚度为4—8mm/2;宫内假环状孕囊28例,大小为4.12mm;宫外探及孕囊178例,大小为8-48mm;盆腔混合性包块28例,大小为40.80mm:伴有黄体囊肿的123例,存活宫外孕3例,可显示原始心管搏动;CDFI声像图特征为宫外孕急性破裂的患者显示肿块及周围组织的彩色血流信号增多,动脉频谱血流速度增快,RI降低。结论超声检查对妇产科急诊有显著性作用,可直接指导临床明确诊断,选定治疗方案。  相似文献   
83.
BACKGROUND: Prior treatment with local hyperthermia has been shown to prevent mast cell degranulation and leucocyte histamine release, and to reduce mortality and cellular infiltrates in a model of acute lung injury. Local hyperthermia is effective in reducing the symptoms of the common cold and perennial and seasonal allergic rhinitis, nasal patency also being improved in rhinitis. It is possible that these effects are mediated by common anti-inflammatory mechanisms, and that this treatment may be effective in the treatment of asthma. The effect of prior local hyperthermia on the response to exercise challenge and histamine bronchoprovocation was therefore examined. METHODS: In a randomised, double blind, placebo controlled, crossover study, 10 asthmatic subjects with exercise induced asthma used machines delivering 40 1/minute of fully humidified air at either 42 degrees C (active treatment) or 31 degrees C (placebo treatment) for 30 minutes' tidal breathing. For each pretreatment, at two week intervals they underwent exercise challenges starting one and 24 hours after starting the inhalations. After a further two weeks the protocol was repeated with histamine substituted for the exercise challenges. RESULTS: The mean (SE) maximum percentage fall in forced expiratory volume in one second (FEV1) was significantly lower one hour after treatment with air at 42 degrees C (30.8% (3.1%)) than after treatment with air at 31 degrees C (22.3% (2.9%)). There was no significant effect on exercise challenge at 24 hours, or on histamine challenge at either time point, though there were nonsignificant trends towards protection with exercise at 24 hours and with histamine at one hour. CONCLUSION: In asthmatic subjects the response to exercise challenge is significantly attenuated one hour after treatment with local hyperthermia. This treatment warrants further investigation in the treatment of clinical asthma and other inflammatory disorders.  相似文献   
84.
85.
86.
The relationship among the dosages of aminophylline, plasma levels of theophylline and variations of mean pulmonary arterial pressure (mPAP) in 72 patients with COPD was investigated. The results showed that after a different loading dosage of aminophylline (6 mg/kg, 5 mg/kg and 4 mg/kg) was administered by intravenous injection, mPAP in the 6 mg/kg group was decreased more significantly (P less than 0.01) than that in the 4 mg/kg group. In the 6 mg/kg group, the decreased mPAP period sustained for 120 min, which was longer than that in the other 2 groups. The plasma levels of theophylline in the 6 mg/kg group of patients 30 to 120 min after loading dose injected were 115.54-79.04 mumol/L, which were higher than that in the others. Within the 120 min period of observation after the drug was administered no patients in any of these groups showed severe untoward effects. According to the results of this experiment, we suggest that the 6 mg/kg as a loading dose should be advised for the treatment of pulmonary hypertension in COPD. The optimum time to give the maintenance dosage should be set within 2 h after the loading dose. It is necessary to monitor the plasma levels of theophylline while aminophylline is administered, so that optimal therapeutic effects could be achieved without side effects.  相似文献   
87.
Q D Lin 《中华妇产科杂志》1992,27(4):209-10, 249-50
The uterine spiral arteries were studied by the immunohistochemical ABC method in 30 cases of Pregnancy Induced Hypertension (PIH) and 10 cases of normal pregnant women. Depositions of IgM and/or C3 on the vessel wall were significantly observed only in PIH cases (15 cases, 50.0%; P < 0.05). Depositions of IgG were seen in 5 cases of PIH 16.7% showing significantly decrease. (P < 0.001), as compared with the normal pregnant women (9 cases, 90.0%). The results suggest that PIH is related to chronic rejection reaction resulting possibly from the decrease of local immunosuppression in pregnancy. Meanwhile the positive stain of IgG, IgM and C3 seen in the nuclei of decidual cells in some of PIH cases were discussed.  相似文献   
88.
89.
90.
Q Lin  J Liao 《中西医结合杂志》1990,10(2):78-81, 68
344 cases of Heart-Qi Deficiency Syndrome (HQDS) including 19 Kinds of disease were observed to explore the rule of differentiation of symptoms and signs for HQDS. The results showed that the common symptoms of HQDS were weakness, shortness of breath, and palpitation, etc. According to with or without complicated cardiovascular diseases, the patients were divided into two groups: group A with cardiovascular diseases, group B without that. In group A, the symptoms and signs of HQDS were the most frequent and early clinical manifestations, the associated symptoms and signs were blood stasis and attack of water-evil, etc. In group B, in whom often associated with nervous and emotional symptoms such as insomnia, dreamfulness, and amnesia, etc., which was due to the disturbance of emotional activities of heart. In order to avoid diagnostic confusion, the authors suggest that the HQDS patients with cardiovascular diseases would be diagnosed as HQDS; on the other hand, the HQDS patients without cardiovascular diseases would be diagnosed as disturbance of emotional activities of heart.  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