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   19484篇
  免费   1278篇
  国内免费   68篇
耳鼻咽喉   175篇
儿科学   439篇
妇产科学   472篇
基础医学   2947篇
口腔科学   816篇
临床医学   2237篇
内科学   4008篇
皮肤病学   353篇
神经病学   1819篇
特种医学   560篇
外科学   1954篇
综合类   128篇
一般理论   9篇
预防医学   1877篇
眼科学   289篇
药学   1480篇
中国医学   108篇
肿瘤学   1159篇
  2023年   186篇
  2022年   249篇
  2021年   497篇
  2020年   309篇
  2019年   521篇
  2018年   708篇
  2017年   501篇
  2016年   547篇
  2015年   699篇
  2014年   767篇
  2013年   1094篇
  2012年   1637篇
  2011年   1682篇
  2010年   785篇
  2009年   656篇
  2008年   1234篇
  2007年   1223篇
  2006年   1171篇
  2005年   1089篇
  2004年   1055篇
  2003年   956篇
  2002年   878篇
  2001年   184篇
  2000年   159篇
  1999年   142篇
  1998年   115篇
  1997年   89篇
  1996年   105篇
  1995年   71篇
  1994年   51篇
  1993年   49篇
  1992年   78篇
  1991年   83篇
  1990年   83篇
  1989年   77篇
  1988年   69篇
  1987年   74篇
  1986年   86篇
  1985年   72篇
  1984年   79篇
  1983年   71篇
  1982年   59篇
  1981年   56篇
  1980年   59篇
  1979年   37篇
  1978年   34篇
  1976年   32篇
  1974年   34篇
  1971年   34篇
  1970年   31篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
101.
OBJECTIVES: To assess the value and clinical impact of integrated PET/CT using (18)F-FDG in the diagnosis and management of women with suspected cervical cancer recurrence. METHODS: Fifty-two patients with cervical cancer with suspected recurrence because of clinical, cytological, biochemical and radiological findings were retrospectively evaluated. A final diagnosis of recurrence was confirmed by histologic tissue biopsy or by further clinical or radiological evidence. The clinical impact of information provided by PET/CT on patient management was assessed on the basis of clinical follow-up data concerning further diagnostic or therapeutic approach. RESULTS: Twenty-eight of 32 positive PET/CT scans (87.5%) were proven to have recurrent disease. Seventeen of 20 negative PET/CT scans (85.0%) had no evidence of disease. The sensitivity, specificity, and accuracy of PET/CT for detecting recurrence were 90.3%, 81.0%, and 86.5% respectively. PET/CT changed the management of 12 patients (23.1%) by changing treatment plan (5 patients), by initiating unplanned treatment strategy (4 patients), or by obviating the need for planned diagnostic procedures (3 patients). Median duration after performing PET/CT and last follow-up was 12 (range: 6-27) months, and the 2-year disease-free survival rate of patients with negative PET/CT scan for recurrence was significantly better than that of patients with positive PET/CT (85.0% vs. 10.9%, P=0002). CONCLUSIONS: In patients with a suspected recurrence of cervical cancer, integrated PET/CT using (18)F-FDG provides good anatomic and functional localization of suspicious lesions, and the better diagnostic interpretation has an impact not only on clinical management and treatment planning of patients, but also on disease-free survival.  相似文献   
102.
103.
104.
105.
106.
Presentation and outcomes of patients with ST-elevation myocardial infarction (STEMI) may change during viral pandemics. We compared symptom-tocall (STC), call-to-balloon (CTB), doorto-balloon (DTB) times; high-sensitivity troponin (hs-cTnI) levels; and survival of patients (n=39) during the first wave of the COVID-19 pandemic (defined as a ‘COVID period’ starting four weeks before lockdown) to historical controls from a ‘pre-COVID period’ (n=45).STEMI admissions fell one week before lockdown by 29%. Median STC times began to rise one month before lockdown (54 vs. 25 min, p=0.06), with peak increases between 9 March and 5 April (166 vs. 59 min, p=0.04). Median CTB and DTB times were unchanged. Mean peak hs-cTnI increased during COVID-19 (15,225 vs. 8,852 ng/ml, p=0.004). Six-month survival following all STEMI reduced (82.1% vs. 95.6%, p<0.05).STC times are the earliest indicator that STEMI-patient behaviour changed four weeks before lockdown, correlating with higher troponin levels and reduced survival. These early signals could guide public health interventions during future pandemics.Key words: COVID-19, outcomes, percutaneous coronary intervention (PCI), ST-elevation myocardial infarction (STEMI)  相似文献   
107.
Psoriasis is an inflammatory autoimmune skin disease with various clinical manifestations. The aim of this review was to systematically evaluate the efficacy and safety of oral administration of East Asian herbal medicine (EAHM) for inflammatory skin lesions in psoriasis and to explore core herbal materials for drug discovery. A comprehensive search was conducted in 10 electronic databases for randomized controlled trials from their inception until 29 July 2021. Statistical analysis was performed in R version 4.1.2 and R studio. When heterogeneity in studies was detected, the cause was identified through sensitivity analysis, meta-regression, and subgroup analysis. Methodological quality was independently assessed using the revised tool for risk of bias in randomized trials. A total of 56 trials with 4966 psoriasis patients met the selection criteria. Meta-analysis favored EAHM monotherapy on Psoriasis Area Severity Index (PASI) 70 (RR: 1.2845; 95% CI: 1.906 to 1.3858, p < 0.0001), PASI 60 (RR: 1.1923; 95% CI: 1.1134 to 1.2769, p < 0.0001), continuous PASI score (MD: −2.3386, 95% CI: −3.3068 to −1.3704, p < 0.0001), IL-17, IL-23, TNF-α, and Dermatology Life Quality Index. Patients treated with EAHM monotherapy had significantly reduced adverse events incidence rate. In addition, based on additional examination of the herb data included in this meta-analysis, 16 core materials were identified. They are utilized in close proximity to one another, and all have anti-inflammatory properties. The findings in this study support that oral EAHM monotherapy may be beneficial for inflammatory skin lesions in psoriasis. Meanwhile, the identified core materials are expected to be utilized as useful drug candidate hypotheses through follow-up studies on individual pharmacological activities and synergistic effects.  相似文献   
108.
Surgery Today - Postoperative pneumonia affects the length of stay and mortality after surgery in elderly patients with colorectal cancer (CRC). We aimed to determine the risk factors of...  相似文献   
109.
The tensile bond strength between zirconia subjected to different surface-pretreatment methods and methacryloyloxydecyl-dihydrogen-phosphate (MDP)-containing self-adhesive resin cement was evaluated herein. Eighty-eight cylindrical zirconia specimens were randomly divided into the following four groups based on the pretreatment method: (1) no treatment, (2) air abrasion, (3) HNO3/HF etching, and (4) zirconia-nanoparticle coating. The tensile bond strength of the zirconia–resin-cement complexes was investigated. One-way ANOVA and post hoc tests were performed at a 95% significance level, and the Weibull modulus was calculated. Fracture patterns were visualized by SEM. The surface roughness of the specimens without resin bonding was evaluated by AFM. The tensile bond strength of the specimens decreased as follows: Groups 3 > 4 > 2 > 1 (28.2 ± 6.6, 26.1 ± 5.7, 16.6 ± 3.3, and 13.9 ± 3.0 MPa, respectively). Groups 3 and 4 had significantly higher tensile bond strengths (p < 0.05) and lower fracture probabilities than those of Groups 1 and 2. They also showed both mixed failure and resin-cement cohesive failure, whereas Groups 1 and 2 showed mixed failure exclusively. The zirconia–resin tensile bond was stronger after HNO3/HF etching or ZrO2-nanoparticle coating than after air abrasion or no treatment. The estimated surface roughness decreased as follows: Groups 3 > 4 > 2 > 1. The combination of zirconia pretreated with HNO3/HF etching or ZrO2-nanoparticle coating and an MDP-containing self-adhesive resin cement can increase the clinical longevity of zirconia restorations by preventing their decementation.  相似文献   
110.
We explored the physiological effects of inhaling basil essential oil (BEO) and/or linalool and identified odor-active aroma compounds in BEO using gas chromatography/mass spectrometry (GC–MS) and GC–olfactometry (GC–O). Linalool was identified as the major volatile compound in BEO. Three groups of rats were administered BEO and linalool via inhalation, while rats in the control group were not. Inhalation of BEO for 20 min only reduced the total weight gain (190.67 ± 2.52 g) and increased the forced swimming time (47.33 ± 14.84 s) compared with the control group (219.67 ± 2.08 g, 8.33 ± 5.13 s). Inhalation of BEO for 5 min (392 ± 21 beats/min) only reduced the pulse compared with the control group (420 ± 19 beats/min). Inhalation of linalool only reduced the weight of white adipose tissue (5.75 ± 0.61 g). The levels of stress-related hormones were not significantly different among the groups. The total cholesterol and triglyceride levels decreased after inhalation of BEO for 20 min (by more than −10% and −15%, respectively). Low-density lipoprotein cholesterol levels were lowered (by more than −10%) by the inhalation of BEO and linalool, regardless of the inhalation time. In particular, BEO inhalation for 20 min was associated with the lowest level of low-density lipoprotein cholesterol (53.94 ± 2.72 mg/dL). High-density lipoprotein cholesterol levels increased after inhalation of BEO (by more than +15%). The atherogenic index and cardiac risk factors were suppressed by BEO inhalation. Animals exposed to BEO and linalool had no significant differences in hepatotoxicity. These data suggest that the inhalation of BEO and linalool may ameliorate cardiovascular and lipid dysfunctions. These effects should be explored further for clinical applications.  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