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   63821篇
  免费   5972篇
  国内免费   4397篇
耳鼻咽喉   682篇
儿科学   592篇
妇产科学   640篇
基础医学   7181篇
口腔科学   1291篇
临床医学   8456篇
内科学   8918篇
皮肤病学   717篇
神经病学   2763篇
特种医学   2060篇
外国民族医学   42篇
外科学   6296篇
综合类   11560篇
现状与发展   20篇
一般理论   14篇
预防医学   4804篇
眼科学   1701篇
药学   6932篇
  82篇
中国医学   3925篇
肿瘤学   5514篇
  2024年   263篇
  2023年   1026篇
  2022年   2601篇
  2021年   3449篇
  2020年   2571篇
  2019年   2061篇
  2018年   2186篇
  2017年   1984篇
  2016年   1806篇
  2015年   3046篇
  2014年   3656篇
  2013年   3157篇
  2012年   4558篇
  2011年   5081篇
  2010年   3514篇
  2009年   2834篇
  2008年   3335篇
  2007年   3375篇
  2006年   3358篇
  2005年   3208篇
  2004年   2362篇
  2003年   2220篇
  2002年   1837篇
  2001年   1528篇
  2000年   1430篇
  1999年   1443篇
  1998年   964篇
  1997年   928篇
  1996年   679篇
  1995年   695篇
  1994年   579篇
  1993年   336篇
  1992年   380篇
  1991年   345篇
  1990年   294篇
  1989年   254篇
  1988年   207篇
  1987年   205篇
  1986年   137篇
  1985年   114篇
  1984年   66篇
  1983年   37篇
  1982年   22篇
  1981年   27篇
  1980年   8篇
  1979年   22篇
  1977年   1篇
  1976年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
用扫描电镜直接观察及硅橡胶一环氧树脂扫描电镜复型技术观察银汞合金、EB复合树脂、玻璃离子粘固粉体外充填与釉质、牙骨/本质壁的边缘密合度。结果表明,与牙体组织呈化学性结合的玻璃离子粘固粉与釉质、牙骨/本质壁的密合度好,两壁之间无差别;EB复合树脂与釉质壁的边缘密合度与玻璃离子粘固粉相似,其缝隙明显小于牙骨/本质壁;银汞合金与釉质壁、牙骨/本质壁的边缘密合度差,且两壁之间无明显差别。  相似文献   
102.
使用围套式显微血管减压术治疗面肌痉挛50例。采用耳后斜行小切口,分离压迫血管后,用涤沦片包绕面神经根起始部并用银夹固定,术后49例痉挛停止。本法并发症少,无死亡。术后随访3个月至10年均无复发。根据术中发现将“责任血管”分为4型:接触型、压迫型、粘连包绕型和贯穿型。讨论了手术适应证、要求及并发症的预防等。  相似文献   
103.
未能切除的胰腺癌行区域性导向化疗临床应用报告   总被引:10,自引:0,他引:10  
自1989-1992年间,作者共收治胰腺癌190例,其中有159例未能切除,对其中30例采用了区域性导向化疗,即在手术中经胃网膜石动脉逆行置管至胃十二指肠动脉,术后经该导管注入5-FU等化疗药物,一般每日250mg,共达1-2个月。根据随诊的108例按手术方式分为A组单纯探查24例,B组单纯胆肠转流54例,C组单纯探查加区域性化疗18例,D组胆肠转流加区域性化疗12例。中位期分别为A组3.5个月,  相似文献   
104.
郑高欣 《眼科研究》1993,11(3):197-199
报告118例(133眼)由各种疾病引起的玻璃体出血机化患者的视网膜电图(ERG)检查结果,其中31例作了玻璃体手术,结果表明,ERG检查对玻璃体出血机化的患者,能客观地反映其网膜功能,并对玻璃体手术的预后有指导作用。术前ERG检查,a、b波下降越严重,视功能损害显著,术后视力的预后越差,同时证实,玻璃体机化膜是影响a、b波波幅和时间的一个因素。  相似文献   
105.
N┐(4┐乙氧苯基)苯甲酰胺类化合物的合成及抗炎、抗变态反应活性研究周玉新1)党永红刘建飞2)徐颖刘百里(沈阳药科大学制药系,沈阳110015)郑文义(东北第六制药厂,沈阳110043)1981年,刘百里等〔1,2〕发现和研制的新药益肤酰胺,经药理实...  相似文献   
106.
拜虫杀和杀飞克对3种卫生害虫的药效报告   总被引:1,自引:0,他引:1  
本文报道了两种菊酯类卫生杀虫剂,在不同载体表面对3种卫生害虫的触杀试验。结果:(1)拜虫杀在玻璃板面上6.25mg/m2时对家蝇速效KT(50)为3.3min;淡色库蚊为4.3min;持效均达49天;对德国小蠊KT(50)为5.6min,持效42天。在木板表面12.5mg/m2时,对家蝇速效KT(50)为4.3min,对淡色库蚊为4.6min,对前者持效49天,后者42天。对德国小蠊KT(50)为4.9min,持效35天。在水泥板面25mg/m2时,对家蝇速效KT(50)为4/min,对淡色库蚊为5.0min,前者持效35天,后者42天。对德国小蠊速效KT(50)为6.4min,持效21天。(2)杀飞克在玻璃面上7.5mg/m2时,对家蝇速效KT(50)为3.7min,对淡色库蚊为5.1min,持效均达49天。在木板面上15mg/m2时,对家蝇速效KT(50)为4.2min,对淡色库蚊为6.0min,对前者持效49天,后者为42天。在水泥板面30mg/m2时,对家蝇速效Kt(50)为4.4min,对淡色库蚊为5.0min,对前者持效35天,后者42天;对德国小蠊速效KT(50)为6.4min,持效21天。  相似文献   
107.
A questionnaire survey was conducted among 7,665 students and staff in the factory-operated industrial colleges in Shanghai, China. Response rate was 95.7 per cent. The proportion of smokers among the men was 50.5 per cent; only 0.33 per cent of the women reported they were smokers. Male smokers began smoking upon entering the work force, where social interaction encourages cigarette smoking. Seventy per cent of the male smokers smoked fewer than 10 cigarettes per day. Only 4.3 per cent perceived themselves as very addicted; 3.4 per cent reported they had no confidence in their ability to control the amount they smoke. The Chinese smokers are more likely to succeed in giving up cigarette smoking for at least one day, as well as for longer periods, compared to US smokers. The number of cigarettes smoked may be related to the individual's purchasing power. For China, strategic timeliness in legislative action and education is urgently needed to combat the high prevalence of cigarette smoking in males, at extremely high risk.  相似文献   
108.
组织多肽特异性抗原在乳腺癌中的临床研究   总被引:16,自引:1,他引:15  
OBJECTIVE: To investigate the expression of serum tissue polypeptide-specific antigen (TPS) in breast cancer patients and its clinical value in such cases. METHODS: Altogether 160 subjects (90 patients with breast cancer, 40 with benign breast lesions, and 30 healthy subjects) were enrolled in this study. The serum TPS and CA153 levels were measured by ELISA in all the subjects. RESULTS: The levels and positivity rate of serum TPS and CA153 in breast cancer group were significantly higher than those in the normal subjects group and benign lesion group (P<0.01), and became even higher as the malignancy progressed. High serum TPS level was detected in the cancer patients in stage I. Serum TPS level was the most sensitive to bone metastasis of the malignancy, but its highest levels occurred in cases of lymphoid node metastasis (P<0.05). In patients who responded favorably to the treatment, serum TPS and CA153 levels were significantly reduced (P<0.05), but the reduction in TPS levels tended to be more obvious (P<0.05). CONCLUSION: Serum TPS can be used as a very useful and sensitive tumor marker in the diagnosis of breast cancer, especially in case of bone metastasis, and may be of great value in clinical decision-making and assessment of therapeutic effect.  相似文献   
109.
BACKGROUND: Inhaled fluticasone propionate (FP) therapy decreases inflammation and sub-basement membrane thickness in asthmatic airways. Bronchiolitis obliterans syndrome (BOS) in lung transplant recipients (LTRs) involves progressive airway fibrosis and obliteration. Therefore, augmented immunosuppression may be of some benefit in treating BOS. In this study, we examined the effect of 3 months of treatment with high-dose inhaled FP on the concentrations of 2 fibrogenic factors, transforming growth factor (TGF)-beta(1) and beta fibrogenic growth factor (bFGF) in bronchoalveolar lavage (BAL) fluid from clinically stable LTRs. METHODS: We conducted a randomized, double-blind, placebo-controlled, parallel group study with inhaled FP (750 microg, twice/day for 3 months) in 28 LTRs (15 FP and 13 placebo). We recruited 23 healthy controls. We performed spirometry, bronchoscopy, and bronchoalveolar lavage procedures before treatment and after 3 months of treatment. We used commercially available enzyme-linked immunosorbent assay kits to measure BAL fluid TGF-beta(1) and bFGF concentrations. RESULTS: In LTRs before treatment, BAL TGF-beta(1) concentrations (but not bFGF concentrations), total cell counts, and neutrophil percentage increased compared with controls (p < 0.05). We found no significant differences between FP and placebo groups at baseline measurements. After treatment, BAL TGF-beta(1) concentrations significantly increased in the FP group (p = 0.03), but we found no difference between FP and placebo groups; BAL bFGF concentrations increased during treatment in both groups compared with controls (p < 0.05), but not significantly within either patient group (p > 0.05). We found a reverse correlation between forced expiratory volume in 1 second (FEV(1)) and BAL TGF-beta(1) concentration in the FP group (r = -0.53, p = 0.04), and between FEV(1) and BAL TGF-beta(1) concentration in the placebo group (r = -0.74, p = 0.004). Multivariable analysis indicated no significant independent effects of inhaled FP in either BAL TGF-beta(1) or bFGF concentrations. CONCLUSIONS: Bronchoalveolar fluid TGF-beta(1) concentrations increased in LTRs after transplantation and may correlate with the decrease in lung function. Inhaled FP added to conventional immunosuppression had no effect on TGF-beta(1) or bFGF production in BAL fluid.  相似文献   
110.
Purpose: To study the changes of telomerase activity and cytotoxic effects by Cisplatin; cis-dichlorodiamine platinum (CDDP) in cultured human choroidal melanoma. Material and Methods: The primary cultured human choroidal melanoma cells were cultured in the presence and absence of CDDP with different concentration and time respectively. The toxic effects were evaluated by MTT and the level of telormarse was detected by PCR-ELISA assay. And the relationship between telomerase activity and cytotoxic effects were analyzed by a correlation analysis.Results: Following the increase of the concentration and the time of CDDP, gradually repressed telomerase activity was detected in cultured cells. Meanwhile, the restrain rate of the cells increased. The telomerase activity at 24h and 1μg/ml was repressed significantly compared with the control cells. However, the appearance of cell death lagged behind the decreasing of telomerase.Conclusions: CDDP is an effective telomerase inhibitor in cultured choroidal melan  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