全文获取类型
收费全文 | 43125篇 |
免费 | 3651篇 |
国内免费 | 1203篇 |
专业分类
耳鼻咽喉 | 840篇 |
儿科学 | 653篇 |
妇产科学 | 547篇 |
基础医学 | 7413篇 |
口腔科学 | 1944篇 |
临床医学 | 3828篇 |
内科学 | 7258篇 |
皮肤病学 | 540篇 |
神经病学 | 3709篇 |
特种医学 | 1178篇 |
外国民族医学 | 4篇 |
外科学 | 2878篇 |
综合类 | 3695篇 |
现状与发展 | 5篇 |
一般理论 | 1篇 |
预防医学 | 3304篇 |
眼科学 | 1388篇 |
药学 | 4487篇 |
12篇 | |
中国医学 | 1441篇 |
肿瘤学 | 2854篇 |
出版年
2024年 | 128篇 |
2023年 | 810篇 |
2022年 | 1620篇 |
2021年 | 2314篇 |
2020年 | 1825篇 |
2019年 | 1606篇 |
2018年 | 1599篇 |
2017年 | 1548篇 |
2016年 | 1580篇 |
2015年 | 1730篇 |
2014年 | 2586篇 |
2013年 | 3526篇 |
2012年 | 2138篇 |
2011年 | 2371篇 |
2010年 | 1841篇 |
2009年 | 1925篇 |
2008年 | 1870篇 |
2007年 | 1731篇 |
2006年 | 1627篇 |
2005年 | 1384篇 |
2004年 | 1215篇 |
2003年 | 1089篇 |
2002年 | 911篇 |
2001年 | 793篇 |
2000年 | 669篇 |
1999年 | 607篇 |
1998年 | 552篇 |
1997年 | 504篇 |
1996年 | 441篇 |
1995年 | 417篇 |
1994年 | 410篇 |
1993年 | 352篇 |
1992年 | 341篇 |
1991年 | 342篇 |
1990年 | 270篇 |
1989年 | 253篇 |
1988年 | 247篇 |
1987年 | 240篇 |
1986年 | 257篇 |
1985年 | 369篇 |
1984年 | 334篇 |
1983年 | 219篇 |
1982年 | 294篇 |
1981年 | 193篇 |
1980年 | 179篇 |
1979年 | 165篇 |
1978年 | 104篇 |
1977年 | 100篇 |
1976年 | 86篇 |
1975年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
211.
目的:探讨听性脑干反应(ABR)和40 Hz听觉相关电位(40Hz AERP)测试的相关性及对聋儿听力评估的重要性。方法:对401例6岁以下聋儿行ABR和40Hz AERP测试并比较。结果:ABR测试无反应者为589耳(73.4%),40 Hz AERP测试无反应者为311耳(19.4%),前者明显高于后者(P<0.01)。两种测试中有残余听力的耳数随阈值的升高,检出率亦升高,结论:ABR测试只反映高频听阈,无反应率高,而40 Hz AERP可显示低、中频的听阈,无反应率低。两种测试应同时进行,可全面了解聋儿的听力损失情况。同时因聋儿多为重度聋,更应及早选配助听器。 相似文献
212.
Anna Gasinska Jan Skolyszewski Tadeusz Popiela Piotr Richter Zbigniew Darasz Krystyna Nowak Joanna Niemiec Beata Biesaga Agnieszka Adamczyk Krzysztof Bucki Krzysztof Malecki Marian Reinfuss Teresa Kowalska 《Journal of gastrointestinal surgery》2007,11(4):520-528
Purpose Assessment of tumor proliferation rate using Bromodeoxyuridine labeling index (BrdUrdLI) as a possible predictor of rectal
cancer response to preoperative radiotherapy (RT).
Methods and material Ninety-two patients were qualified either to short RT (5 Gy/fraction/5 days) and surgery about 1 week after RT (schedule I),
or to short RT and 4–5 weeks interval before surgery (schedule II). Tumor samples were taken twice from each patient: before
RT and at the time of surgery. The samples were incubated with BrdUrd for 1 h at 37°C, and the BrdUrdLI was calculated as
a percentage of BrdUrd-labeled cells.
Results Thirty-eight patients were treated according to schedule I and 54 patients according to schedule II. Mean BrdUrdLI before
RT was 8.5% and its value did not differ between the patients in the two compared groups. After RT tumors showed statistically
significant growth inhibition (reduction of BrdUrdLI). As the pretreatment BrdUrd LI was not predictive for early clinical
and pathologic tumor response, prognostic role of the ratio of BrdUrdLI after to BrdUrdLI before RT was considered. The ratios
were calculated separately for fast (BrdUrd LI > 8.5%) and slowly (BrdUrd LI ≤ 8.5%) proliferating tumors and correlated with
overall treatment time (OTT, i.e., time from the first day of RT to surgery). One month after RT, accelerated proliferation
was observed only in slowly proliferating tumors.
Conclusions Pretreatment BrdUrdLI was not predictive for early clinical and pathologic tumor response. The ratio after/before RT BrdUrdLI
was correlated to inhibition of proliferation in responsive tumors.
The paper was presented at ECCO 13, October 30 to November 03, 2005 in Paris, France 相似文献
213.
在辅助生殖助孕中通常采用控制性卵巢刺激(controlled ovarian hyperstimulation, COS),以获得适当数量的卵子用于体外受精,既希望获得理想的辅助生殖助孕成功率,又能降低卵巢过度刺激并发症.COS中约有9%~24%[1,2]的卵巢低反应发生率.卵巢低反应者获得有效卵子数少、可移植胚胎数少或无胚胎移植、取消治疗周期率高,累计成功率更低等,导致较差的治疗结局,是辅助生殖助孕中面临的棘手问题.针对卵巢低反应者,大多数辅助生殖中心仍会采用增加促性腺激素(Gn)的起始和(或)总用量以期获得提高助孕结局的目的.而大剂量Gn是否为改善低反应患者助孕结局的有效策略却仍存在争议. 相似文献
214.
Robert G Pinkerton James P Near Enzo A Barberi Ravi S Menon Robert Bartha 《Magnetic resonance in medicine》2007,57(2):455-458
A novel torso transceive surface coil array for prostate magnetic resonance imaging (MRI) and spectroscopy (MRS) at 4T is presented. It is shown that with the use of a conformal transceive surface coil array with 50 Omega transmitter amplifiers and receiver preamplifiers, one can perform whole-volume torso imaging while maintaining the high signal-to-noise ratio (SNR) inherent to surface coil designs. Recent theoretical considerations have shown that by focusing the infringing radiofrequency (RF) electromagnetic field, one can achieve increased penetration and signal homogeneity compared to a conventional circularly polarized driving scheme. A variation of this driving scheme particular to the proposed coil design resulted in a twofold increase in SNR in the prostate compared to that achieved with a conventional circularly polarized driving scheme. The novel transceive surface coil array presented is capable of full-volume imaging of the human torso at 4T while maintaining signal penetration in the deep region of the prostate gland. 相似文献
215.
Hongning Zhao Xiaoming Wang Junqiang Zhang Deben Yang Xiaoqiong Zhao Xin Liu Hui Huang Jianxiu Hu 《中国神经再生研究》2007,2(11):675-677
BACKGROUND: The examination of sympathetic skin response is an important index for assessing the autonomic nerve function, and patients with myasthenia gravis are always accompanied by dysautonomia. Therefore, it will be important to know whether sympathetic skin response can be used as the index for the clinical evaluation of myasthenia gravis.
OBJECTIVE: To investigate the diagnostic value of sympathetic skin response in the damage of autonomic nerve function of patients with myasthenia gravis.
DESIGN: A case-controlled comparative observation.
SETTING: Department of Neurology and Room of Nerve Electromyogram, the Affiliated Hospital of North Sichuan Medical College.
PARTICIPANTS: Thirty outpatients or inpatients with myasthenia gravis were selected from the Department of Neurology, the Affiliated Hospital of North Sichuan Medical College from May 2006 to May 2007, including 9 males and 21 females, aged 8–72 years with a mean age of (28±5) years old. They were all accorded with the diagnostic standards of myasthenia gravis, accompanied by different severity of autonomic nerve symptoms, including poor skin nutrition, sweating of hands and feet, pyknocardia, persistent hypotension, abdominal pain, constipation, etc. They all had not taken any drug affecting the autonomic nerve function before the examination. Informed consents were obtained from all the patients. Meanwhile, 30 healthy physical examinees were enrolled as the normal control group, including 10 males and 20 females, aged 10–75 years with a mean age of (31±5) years old. Approval was obtained from the hospital ethic committee.
METHODS: After admission, the patients were examined with sympathetic skin response using DANTEC keypoint 2.0 electromyography evoked potential apparatus (Danmark). The changes of the latency and wave amplitude of sympathetic skin response were observed. The subjects in the normal control group were examined with the same methods at physical examination. Abnormality was judged by the disappearance of wave form, latency longer than that in the normal control group by Mean±2.5SD, or wave amplitude lower than the average value in the normal control group by 50%.
MAIN OUTCOME MEASURES: The results of the latency and wave amplitude of sympathetic skin response were compared between the patients with myasthenia gravis and normal controls.
RESULTS: All the 30 patients with myasthenia gravis and 30 healthy physical examinees were involved in the final analysis of results. There were no significant differences between the left and right upper and lower limbs in both the myasthenia gravis group and normal control group (P > 0.05). In the myasthenia gravis group, the abnormal rate of sympathetic skin response was 37% (11/30), the latency was prolonged and the wave amplitude was decreased as compared with those in the normal control group, and there were significant differences (P < 0.01).
CONCLUSION: Sympathetic skin response can be used as an electrophysiological index for judging the damages of autonomic nerve function in patients with myasthenia gravis. 相似文献
216.
Despite continued improvement in incidence of acute immune injury and short-term graft survival, late allograft dysfunction remains a significant problem in the renal transplant population. Recent reports suggest that rates of renal function decline are quite varied in the overall recipient population, and that individual rates for many recipients may not change substantially over time. Moreover, analyses also reveal distinct predictive factors for both early and late functional decline. Long-term outcome studies for renal transplantation, however, might be significantly limited by incomplete data sets for assessing clinical endpoints. In view of the heterogeneous factors that may cause progressive allograft injury, more routine biopsy sampling would allow a more complete characterization of induced injuries. Elucidating mechanisms of renal fibrosis in response to injury, in experimental systems and humans, is also an important goal in better understanding chronic allograft damage. Regulation of cell senescence genes and epithelial to mesenchymal transition, studied in other models of renal fibrosis, are likely relevant to studies of renal allograft dysfunction. Recent technical advances in analyzing biological samples may play a pivotal role in identifying and validating surrogate markers of allograft function for future interventional trials in transplantation. 相似文献
217.
由聚酯二元醇、异佛尔酮二异氰酸酯和二羟甲基丙酸合成聚氨酯预聚体,以氨乙基氨丙基聚二甲基硅氧(AEAPS)为扩链剂,制备了AEAPS改性聚氨酯水分散液。与未改性的聚氨酯水分散液相比,AEAPS改性聚氨酯水分散液的粒径增大,但粒径分布和表面张力基本不变,说明疏水的聚二甲基硅氧烷侧链被包裹于分散颗粒的内部;此外,改性聚氨酯水分散液的冻融稳定性显著增强。AEAPS改性聚氨酯水分散液成膜后,吸水率明显下降,水在膜表面的接触角增加,400℃时热失重下降,具有良好的疏水性和耐热性。 相似文献
218.
成人肌间沟臂丛神经阻滞运动反应终点的研究 总被引:2,自引:0,他引:2
目的研究胸大肌、三角肌运动反应作为外周神经刺激器(PNS)定位下成人经肌间沟臂丛神经阻滞终点的可行性。方法择期成人上肢手术240例,PNS定位下行经肌间沟臂丛神经阻滞,随机均分为四组:胸大肌运动反应终点组(A组)、三角肌运动反应终点组(B组)、肱二头肌运动反应终点组(C组)和胸大肌、三角肌或肱二头肌运动反应终点组(D组)。比较组间刺激域电流、获得终点时间、运动阻滞起效时间、各神经分支感觉阻滞起效时间、运动阻滞效果、各神经分支感觉阻滞效果及神经阻滞综合效果。结果D组获得终点时间短于A、B、C组(P<0.05),组间刺激域电流、运动阻滞起效时间、各神经分支感觉阻滞起效时间、运动阻滞效果、各神经分支感觉阻滞效果及神经阻滞综合效果差异无统计学意义。神经阻滞综合优良率90.8%。结论胸大肌、三角肌运动反应终点可作为PNS定位下成人经肌间沟臂丛神经阻滞穿刺针正确定位的满意、安全标志。 相似文献
219.
舒芬太尼或芬太尼复合丙泊酚对喉显微手术血流动力学和应激反应的影响 总被引:2,自引:1,他引:1
目的 比较芬太尼复合丙泊酚与舒芬太尼复合丙泊酚用于喉显微手术患者的血流动力学和应激激素变化.方法 200例患者行支撑喉镜下声带手术,患者随机均分为芬太尼复合丙泊酚组(F组)和舒芬太尼复合丙泊酚组(S组).F组、S组分别静脉注射芬太尼3.0μg/kg或舒芬太尼0.3μg/kg、丙泊酚2.0mg/kg、琥珀胆碱1.5mg/kg实施麻醉诱导.记录和测定两组诱导前(T0)、插管即刻(T1)、插管后1min(T2)、置支撑喉镜后1min(T3)及拔管后1min(T6)的SBP、DBP、HR、去甲肾上腺素(NE)、皮质醇(Cor)、血糖(Glu)的变化和丙泊酚用量、麻醉恢复情况及不良反应.结果 F组T1、T2、T3时SBP、DBP高于、HR快于T0和S组(P<0.05).F组T1~T3时NE、Cor、Glu分别显著高于T0和S组(P<0.05).术中丙泊酚追加量和总用药量F组显著高于S组(P<0.05),麻醉恢复时间S组稍长于F组,但差异无统计学意义.结论 舒芬太尼复合丙泊酚麻醉对血流动力学和应激反应影响小,是喉显微手术中比较理想的麻醉配伍组合. 相似文献
220.
A. Keshava P. H. Chapuis C. Chan† B. P. C. Lin† E. L. Bokey O. F. Dent 《Colorectal disease》2007,9(7):609-618
OBJECTIVE: To determine whether the presence of tumour at a free serosal surface was independently associated with pelvic recurrence or survival in patients who had a resection for clinicopathological stage B or stage C rectal cancer and who had not received adjuvant therapy. METHOD: Data were drawn from a comprehensive, prospective hospital registry of all resections for rectal cancer from January 1971 to December 1998 with follow up to December 2003. Statistical analysis employed the chi(2) test or Fisher's exact probability, Kaplan-Meier estimation and proportional hazards regression, with a significance level of < or =0.05 and 95% confidence intervals (CI). RESULTS: In 665 patients with stages B or C tumour, 35 (5.3%; CI 3.7-7.2%) had tumour at a free serosal surface. These comprised 6/332 (1.8%; CI 0.8-3.7%) patients with stage B tumour and 29/333 (8.7%; CI 6.1-12.2%) with stage C tumour. After adjustment for other relevant variables, involvement of a free serosal surface was significantly associated with pelvic recurrence [hazard ratio (HR) 2.7; CI 1.3-5.5] and diminished survival (HR 1.6; CI 1.1-2.4) but not with systemic (only) recurrence. CONCLUSION: This study has confirmed that direct tumour spread to a free serosal surface independently predicts pelvic recurrence and diminished survival after resection of clinicopathological stage B and C rectal cancer. This feature should always be sought by the pathologist and reported when present, and noted by the surgeon and oncologist. Serosal involvement should be evaluated further for its utility in selecting patients for adjuvant therapy. 相似文献