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   47161篇
  免费   3139篇
  国内免费   2320篇
耳鼻咽喉   1670篇
儿科学   323篇
妇产科学   137篇
基础医学   6440篇
口腔科学   1106篇
临床医学   3818篇
内科学   2127篇
皮肤病学   2384篇
神经病学   9184篇
特种医学   1690篇
外国民族医学   2篇
外科学   9829篇
综合类   6119篇
现状与发展   1篇
预防医学   754篇
眼科学   2519篇
药学   2327篇
  28篇
中国医学   1296篇
肿瘤学   866篇
  2024年   85篇
  2023年   729篇
  2022年   1140篇
  2021年   1700篇
  2020年   1767篇
  2019年   1476篇
  2018年   1396篇
  2017年   1720篇
  2016年   1738篇
  2015年   1678篇
  2014年   2826篇
  2013年   2960篇
  2012年   2372篇
  2011年   2543篇
  2010年   2279篇
  2009年   2064篇
  2008年   2204篇
  2007年   2137篇
  2006年   2004篇
  2005年   1759篇
  2004年   1588篇
  2003年   1487篇
  2002年   1263篇
  2001年   1123篇
  2000年   958篇
  1999年   880篇
  1998年   843篇
  1997年   765篇
  1996年   618篇
  1995年   563篇
  1994年   507篇
  1993年   464篇
  1992年   482篇
  1991年   410篇
  1990年   412篇
  1989年   342篇
  1988年   313篇
  1987年   329篇
  1986年   300篇
  1985年   401篇
  1984年   342篇
  1983年   238篇
  1982年   272篇
  1981年   237篇
  1980年   231篇
  1979年   163篇
  1978年   116篇
  1977年   107篇
  1976年   88篇
  1975年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
《Clinical neurophysiology》2021,132(9):2003-2011
ObjectiveA large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS.MethodsA total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis.ResultsPatients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively).ConclusionsThe HFO amplitude in ALS is increased, but does not predict survival.SignificanceThe enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons.  相似文献   
3.
ObjectiveTo determine if individuals with chronic ankle instability (CAI) demonstrate altered landing kinematics, muscle activity, and impaired dynamic postural stability during a unilateral jump-landing task.Methods21 studies were included from PubMed, MEDLINE, Embase and CINAHL searched on September 26, 2021. Mean differences in joint angles and muscle activity between CAI and controls were analysed as continuous variables and pooled using a random-effects model to obtain standardised mean differences and 95% confidence intervals. Dynamic postural stability measured using time to stabilisation (TTS) was assessed qualitatively.ResultsWe found greater plantarflexion (pooled SMD = 0.33, 95%CI [0.02,0.65]), reduced knee flexion (pooled SMD = −0.67, 95%CI [−0.97, −0.37]), and reduced hip flexion (pooled SMD = −0.52, 95%CI [−0.96, −0.07]) in CAI after landing. Regarding muscle activity, we observed reduced peroneus longus muscle activation (pooled SMD = −0.77, 95% CI [−1.17, −0.36]) in CAI prior to landing.ConclusionOur study provides preliminary evidence of altered landing kinematics in the sagittal plane and reduced peroneus muscle activity in CAI during a dynamic jump-landing task. These results may have clinical implications in the development of more effective and targeted rehabilitation programmes for patients with CAI.  相似文献   
4.
Cutaneous leiomyomas are rare benign smooth‐muscle tumors. These lesions are distinguished based on their cell of origin and are subclassified as pilar leiomyoma, angioleiomyoma, and genital‐type leiomyoma. Nipple leiomyoma is the least common genital‐type leiomyoma, arising from the dartoic muscle cell of the nipple. Histologic examination of the lesion is necessary for definitive diagnosis, and these uncommon tumors can pose a diagnostic challenge. We describe herein a series of six nipple leiomyomas with a spectrum of histologic appearances.  相似文献   
5.
目的对比动力髋螺钉(dynamic hip screw,DHS)治疗和股骨近端抗旋髓内钉(proximal femoral nail anti-rotation,PFNA)固定治疗老年股骨粗隆间骨折疗效。方法纳入本院收治的45例采用PFNA固定治疗的老年股骨粗隆间骨折患者作为研究组,研究时间为2017年11月-2018年11月;回顾性分析2016年11月-2017年11月在我院采用DHS治疗的45例老年股骨粗隆间骨折患者的临床资料,作为对照组。记录两组的相关手术指标,观察手术并发症情况。结果研究组的手术时间和骨折愈合时间均短于对照组,术中出血量明显少于对照组,术后疼痛VAS评分均明显低于对照组(P<0.05)。对照组的并发症发生率高于研究组(P<0.05)。结论PFNA固定治疗比DHS治疗老年股骨粗隆间骨折更加安全有效,值得临床借鉴和应用。  相似文献   
6.
IntroductionThere is still no consensus in the literature as to the best acoustic stimulus for capturing vestibular evoked myogenic potential (VEMP). Low-frequency tone bursts are generally more effective than high-frequency, but recent studies still use clicks. Reproducibility is an important analytical parameter to observe the reliability of responses.ObjectiveTo determine the reproducibility of p13 and n23 latency and amplitude of the VEMP for stimuli with different tone-burst frequencies, and to define the best test frequency.MethodsCross-sectional cohort study. VEMP was captured in 156 ears, on the sternocleidomastoid muscle, using 100 tone-burst stimuli at frequencies of 250, 500, 1000, and 2000 Hz, and sound intensity of 95 dB nHL. Responses were replicated, that is, recorded three times on each side.ResultsNo significant difference was observed for p13 and n23 latencies of the VEMP, captured at three moments with tone-burst stimuli at 250, 500, and 1000 Hz. Only the frequency of 2000 Hz showed a difference between captures of this potential (p < 0.001). p13 and n23 amplitude analysis was also similar in the test–retest for all frequencies analyzed.Conclusionp13 and n23 latencies and amplitudes of VEMP for tone-burst stimuli at frequencies of 250, 500, and 1000 Hz are reproducible.  相似文献   
7.
8.
9.
10.
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