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   5846篇
  免费   292篇
  国内免费   190篇
耳鼻咽喉   14篇
儿科学   55篇
妇产科学   66篇
基础医学   993篇
口腔科学   47篇
临床医学   343篇
内科学   660篇
皮肤病学   23篇
神经病学   190篇
特种医学   500篇
外科学   1812篇
综合类   379篇
现状与发展   1篇
预防医学   124篇
眼科学   15篇
药学   153篇
  1篇
中国医学   29篇
肿瘤学   923篇
  2024年   11篇
  2023年   138篇
  2022年   287篇
  2021年   326篇
  2020年   252篇
  2019年   265篇
  2018年   258篇
  2017年   203篇
  2016年   177篇
  2015年   234篇
  2014年   357篇
  2013年   401篇
  2012年   223篇
  2011年   232篇
  2010年   213篇
  2009年   258篇
  2008年   298篇
  2007年   286篇
  2006年   277篇
  2005年   220篇
  2004年   220篇
  2003年   160篇
  2002年   147篇
  2001年   171篇
  2000年   94篇
  1999年   103篇
  1998年   104篇
  1997年   67篇
  1996年   57篇
  1995年   41篇
  1994年   38篇
  1993年   42篇
  1992年   32篇
  1991年   14篇
  1990年   14篇
  1989年   10篇
  1988年   12篇
  1987年   14篇
  1986年   8篇
  1985年   17篇
  1984年   6篇
  1983年   6篇
  1982年   6篇
  1981年   4篇
  1980年   5篇
  1979年   2篇
  1978年   6篇
  1977年   4篇
  1976年   3篇
  1975年   4篇
排序方式: 共有6328条查询结果,搜索用时 19 毫秒
21.
近年来越来越多的证据支持炎症反应在动脉粥样硬化及并发症的发生和发展中起重要作用。炎症过程中最具标志性因子CRP,被认为与动脉粥样硬化、冠心病的发生发展以及预后有密切的关系。血脂康的原料为特制红曲,是一种天然复合他汀,并含有不饱和脂肪酸、微量元素、氨基酸、麦角甾醇、生物碱和黄酮类物质。  相似文献   
22.
Intrauterine growth restriction is known to be associated with many medical problems for the baby, both before and after delivery. The mechanisms involved in fetal growth are not well understood, with an increasing range of metabolic diseases being implicated. Several key genes involved in normal embryonic and fetal growth and development are now known to be imprinted. Disruption of this parent-specific mono-allelic expression causes phenotypic changes, many of which are important for growth and development. Two growth disorders, Beckwith–Wiedemann syndrome and Silver–Russell syndrome, are discussed in detail as they represent well-characterized phenotypes that arise as a consequence of disrupted imprinting. These human models will allow us to elucidate key genes and mechanisms important in normal fetal growth.  相似文献   
23.
One important aspect of utilizing transgenic mice is the need to genotype them in order to distinguish mice that carry a disrupted gene or a transgene from mice that do not. Current methods for genotyping include isolation of genomic DNA from tail biopsies followed by PCR amplification. Particularly, both digestion of tail tissue using proteinase K as well as resuspension of purified DNA are time-consuming and were usually carried out overnight. Here, we describe a rapid and robust method for the genotyping of bdnf targeted mice which allows us to determine the genotype of newborn mice at the day of birth within 6 h. After a freezing–thawing step tail tissue is digested in less than 2 h, and the DNA is precipitated, resuspended and ready for PCR in about 60 min. The method could be easily adapted to a variety of different mutant mice and especially should benefit neuroscientists interested in using animals with known genotype very early in postnatal development.  相似文献   
24.
ObjectiveTo translate the original English version of the Spinal Instability Neoplastic Score (SINS) into simplified Chinese, adapt it cross‐culturally, validate its psychometric properties in measuring spinal instability in patients with metastatic spinal tumors in the Chinese mainland, examine the reliability and validity to demonstrate its accuracy and applicability in clinical practice.MethodsPatients diagnosed with metastatic spinal disease between January 2016 and January 2020 were recruited. The number of participants was advised to be at least 50 for appropriate analysis of reliability, construct validity, as well as ceiling or floor effects, and recruitment of 100 patients was advised for internal consistency analysis. The study was conducted in two phases: first, the SINS was translated into simplified Chinese; second, the factor structure, internal consistency, test–retest reliability, validity, and floor and ceiling effects of the SC‐SINS were assessed. The internationally recognized cross‐cultural adaptation guidelines were followed. Internal consistency was evaluated with Cronbach''s alpha. Test–retest reliability was examined among the patients with a 4‐week interval. The validity of the Chinese version of SINS (SC‐SINS) was assessed by examining its relationship with Kostuik classification. Principal component analysis was conducted to confirm the factor structure of each subscale.ResultsA total of 160 participants (88 males and 72 females) were enrolled. No major difficulties occurred in the forward and backward translations of SINS. The internal consistency of SC‐SINS was excellent (Cronbach''s α =0.857, ranging from 0.68 to 0.85). Test–retest reliability was also excellent with a value of 0.89, ranging from 0.86 to 0.95. Validity analyses indicated that the SC‐SINS was positively and significantly correlated with Kostuik classification. The correlation between “Posterolateral Involvement of Spinal Elements” and “1‐2 Partial Damage” was the highest with a correlation value of 0.792. The correlation between “Pain” and “1–2 Partial Damage” was the lowest with a value of 0.341. All items showed principal component coefficients greater than 0.4. The values of Factor 1 ranged from 0.523 to 0.681; Factor 2 ranged from 0.591 to 0.731; Factor 3 ranged from 0.613 to 0.754; Factor 4 ranged from 0.461 to 0.711; Factor 5 ranged from 0.513 to 0.701; and Factor 6 ranged from 0.501 to 0.668. In addition, neither floor nor ceiling effects were seen in the SC‐SINS.ConclusionThe SC‐SINS demonstrated high internal consistency and test–retest reliability, which has been proven valid and reliable to measure spinal stability in patients from the Chinese mainland with metastatic spinal tumor.  相似文献   
25.
Rich in polyphenols, cranberry juice (CJ) with high antioxidant activity is believed to contribute to various health benefits. However, our knowledge of the neuroprotective potential of cranberries is limited. Previously, we have demonstrated that CJ treatment controls oxidative stress in several organs, with the most evident effect in the brain. In this study, we examined the capability of CJ for protection against Parkinson’s disease (PD) in a rotenone (ROT) rat model. Wistar rats were administered with CJ in a dose of 500 mg/kg b.w./day (i.g.) and subcutaneously injected with ROT (1.3 mg/kg b.w./day). The experiment lasted 45 days, including 10 days pre-treatment with CJ and 35 days combined treatment with CJ and ROT. We quantified the expression of α-synuclein and apoptosis markers in the midbrain, performed microscopic examination, and assessed postural instability to evaluate the CJ neuroprotective effect. Our results indicate that the juice treatment provided neuroprotection, as evidenced by declined α-synuclein accumulation, Bax and cleaved/active caspase-9 expression, and normalized cytochrome c level that was accompanied by the enhancement of neuronal activity survival and improved postural instability. Importantly, we also found that long-term administration of CJ alone in a relatively high dose may exert a deleterious effect on cell survival in the midbrain.  相似文献   
26.
目的 探究踝关节不稳中距腓前韧带(anterior talofibular ligament, ATFL)的厚度与弹性模量对踝关节稳定性的影响,为踝关节不稳患者的诊断提供参考依据。 方法 建立踝关节三维有限元模型,改变 ATFL 的厚度与弹性模量,计算踝关节前后向刚度(ankle anteroposterior stiffness, AAS),并作为量化指标评估踝关节稳定性。 结果 ATFL厚度在 0. 78~ 2. 31 mm 范围内引起 AAS 的大幅度变化,且两者关系呈 S 形曲线;ATFL 弹性模量在 60 ~ 400 MPa 变化范围,AAS 随韧带弹性模量增加快速上升。 结论 ATFL 厚度与弹性模量均会影响踝关节的稳定性。  相似文献   
27.
28.
Detrusorinstability (DI)isacommonurologicprob lem .Atpresent ,thepathogenesisofDIhasn’tbeeneluci dated .Gapjunctions (GJ)areuniquechannelsthattrans mitionsandsmallmolecularmetabolitesbetweenadjacentcells .Theyplayanimportantroleinmaintainingexcitatorycommunicationamongadjacentcells[1] .Recentstudiesofthedetrusorhavesuggestedanewviewpointforthepatho genesisofDI[2 ] .Detrusorisakindofexcitabletissue ,andtheexcitabilityofdetrusormayplayakeyroleintheoccur renceofDI ,buttherewerenoreportsabou…  相似文献   
29.
Post-traumatic ulnar carpal translocation is a rare, severe ligamentous injury to the wrist. Radiologic findings include widening of the radiocarpal joint space at the radial styloid process and ulnar displacement of the carpus. Less than 50% of the lunate articulates with the radius in the neutral position; the lunate is tilted dorsally with palmar subluxation due to a ruptured radioscapholunate (RSL) ligament. This malposition should be called rotatory palmar subluxation of the lunate (RPSL), by analogy to rotatory subluxation of the scaphoid (RSS). In contrast to dorsiflexed intercalated segment instability (DISI), in RPSL the RSL ligament is ruptured and, in the majority of cases, the scapholunate ligament remains intact. A prompt diagnosis should lead to successful treatment.  相似文献   
30.
The purpose of this study was to evaluate prospectively the findings during shoulder arthroscopy in patients with recurrent anterior instability of the gleno-humeral joint. One hundred and seventy-eight patietns who fulfilled the criteria of having had at least one documented shoulder dislocation were included in the study. The pathological findings most frequently noted at arthroscopy were: anterior glenoid labral tears (85%), ventral capsule insufficiency (80%), Hill-Sachs compression fractures (67%), glenohumeral ligament insufficiency (55%), rotator cuff tears (20%), posterior glenoid labral tears (8%), and SLAP lesions (5%). Abnormalities were noted more frequently than expected, and there were significant differences between preoperative and postoperative diagnoses. Our study has taught us that a mulitplicity of morphological changes are associated with instability of the glenohumeral joint, and that there is no single cause. The labrum and rim of the anterior inferior glenoid, for instance, showed typical abnormalities corresponding to different entities of anterior instability. In practice, this is very important, as the abnormalities visualized by imaging methods determine the surgical treatment.  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