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   32506篇
  免费   3367篇
  国内免费   2324篇
耳鼻咽喉   226篇
儿科学   351篇
妇产科学   208篇
基础医学   3352篇
口腔科学   490篇
临床医学   4405篇
内科学   4637篇
皮肤病学   321篇
神经病学   1611篇
特种医学   1152篇
外国民族医学   15篇
外科学   2963篇
综合类   6441篇
现状与发展   13篇
预防医学   2451篇
眼科学   928篇
药学   3772篇
  51篇
中国医学   2248篇
肿瘤学   2562篇
  2024年   98篇
  2023年   540篇
  2022年   1524篇
  2021年   2083篇
  2020年   1471篇
  2019年   1190篇
  2018年   1311篇
  2017年   1172篇
  2016年   1060篇
  2015年   1669篇
  2014年   2053篇
  2013年   1866篇
  2012年   2744篇
  2011年   2763篇
  2010年   1926篇
  2009年   1579篇
  2008年   1690篇
  2007年   1676篇
  2006年   1562篇
  2005年   1256篇
  2004年   1037篇
  2003年   1145篇
  2002年   869篇
  2001年   753篇
  2000年   573篇
  1999年   561篇
  1998年   290篇
  1997年   336篇
  1996年   251篇
  1995年   214篇
  1994年   177篇
  1993年   96篇
  1992年   121篇
  1991年   113篇
  1990年   93篇
  1989年   69篇
  1988年   76篇
  1987年   62篇
  1986年   52篇
  1985年   32篇
  1984年   16篇
  1983年   13篇
  1982年   6篇
  1981年   3篇
  1980年   3篇
  1979年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
目的探讨主诉记忆力减退的非痴呆性血管性认知功能障碍(VCIND)患者脑内神经递质活动的变化及意义。方法选择2008—2012年第二炮兵总医院神经内科门诊患者716例,其中主诉记忆力减退的VCIND组370例,正常对照组346例。采用简易精神状态量表(MMSE)、蒙特利尔认知测评量表(MoCA)进行认知评估。应用脑电超慢涨落(EFG)分析仪测定S1γ-氨基丁酸(GABA)、S2谷氨酸(Glu)、S4 5-羟色胺(5-HT)、S5乙酰胆碱(Ach)、S7去甲肾上腺素(NE)、S11多巴胺(DA)等脑神经递质的活动。结果观察组GLU、5-HT的活动存在异常,GLU显著高于对照组(P<0.05),5-HT显著低于对照组(P<0.05);GABA、Ach、NE、DA的活动与对照组比较,差异无统计学意义(P>0.05)。结论主诉记忆力减退的VCIND人群脑内神经递质谷氨酸、5-羟色胺活动异常。EFG分析可作为一种有效的VCIND辅助诊断方法。  相似文献   
972.
Adrenocorticotropic hormone is recommended worldwide as an initial therapy for infantile spasms. However, infantile spasms in about 50% of children cannot be fully controlled by adrenocorticotropic hormone monotherapy, seizures recur in 33% of patients who initially respond to adrenocorticotropic hormone monotherapy, and side effects are relatively common during adrenocorticotropic hormone treatment. Topiramate, vitamin B 6 , and immunoglobulin are effective in some children with infantile spasms. In the present study, we hypothesized that combined therapy with adrenocorticotropic hormone, topiramate, vitamin B 6 , and immunoglobulin would effectively treat infantile spasms and have mild adverse effects. Thus, 51 children newly diagnosed with West syndrome including infantile spasms were enrolled and underwent polytherapy with the four drugs. Electroencephalographic hypsarrhythmia was significantly improved in a majority of patients, and these patients were seizure-free, had mild side effects, and low recurrence rates. The overall rates of effective treatment and loss of seizures were significantly higher in cryptogenic children compared with symptomatic children. The mean time to loss of seizures in cryptogenic children was significantly shorter than in symptomatic patients. These findings indicate that initial polytherapy with adrenocorticotropic hormone, topiramate, vitamin B 6 , and immunoglobulin effectively improves the prognosis of infantile spasms, and its effects were superior in cryptogenic children to symptomatic children.  相似文献   
973.
Secondary damage is a critical determinant of the functional outcome in patients with spinal cord injury (SCI), and involves multiple mechanisms of which the most important is the loss of nerve cells mediated by multiple factors. Autophagy can result in cell death, and plays a key role in the development of SCI. It has been recognized that valproic acid (VPA) is neuroprotective in certain experimental animal models, however, the levels of autophagic changes in the process of neuroprotection by VPA treatment following SCI are still unknown. In the present study, we determined the extent of autophagy after VPA treatment in a rat model of SCI. We found that both the mRNA and protein levels of Beclin-1 and LC3 were significantly increased at 1, 2, and 6 h after SCI and peaked at 2 h; however, Western blot showed that autophagy was markedly decreased by VPA treatment at 2 h post-injury. Besides, post-SCI treatment with VPA improved the Basso-Beattie-Bresnahan scale, increased the number of ventral horn motoneurons, and reduced myelin sheath damage compared with vehicle-treated animals at 42 days after SCI. Together, our results demonstrated the characteristics of autophagy expression following SCI, and found that VPA reduced autophagy and enhanced motor function.  相似文献   
974.
975.
976.
977.
Major depressive disorder is prevalent worldwide, and only about half of those affected will experience no further episodes or symptoms. Additionally, depressive symptoms can be challenging to identify, with many patients going undiagnosed despite a wide variety of available treatment options. Antidepressants are the cornerstone of depression treatment; however, a large number of factors must be considered in selecting the treatment best suited to the individual. To help support physicians in this process, international and national treatment guidelines have been developed. This review evaluates the current use of antidepressant treatment for major depressive disorder in six Asian countries (China, Korea, Malaysia, Philippines, Taiwan, and Thailand). No remarkable differences were noted between Asian and international treatment guidelines or among those from within Asia as these are adapted from western guidelines, although there were some local variations. Importantly, a shortage of evidence‐based information at a country level is the primary problem in developing guidelines appropriate for Asia, so most of the guidelines are consensus opinions derived from western research data utilized in western guidelines. Treatment guidelines need to evolve from being consensus based to evidence based when evidence is available, taking into consideration cost/effectiveness or cost/benefit with an evidence‐based approach that more accurately reflects clinical experience as well as the attributes of each antidepressant. In everyday practice, physicians must tailor their treatment to the patient's clinical needs while considering associated external factors; better tools are needed to help them reach the best possible prescribing decisions which are of maximum benefit to patients.  相似文献   
978.
BackgroundA growing body of findings illustrates the importance of state-dependency in studies using brain stimulation.ObjectiveWe aimed to investigate the effects of tDCS priming followed by rTMS applied over the right dorsolateral prefrontal cortex (DLPFC) on emotional working memory.MethodsIn a randomized single-blind within-subjects design, participants performed an emotional 3-back task at baseline and after tDCS priming (anodal, cathodal) and subsequent low-frequency rTMS (active, sham) of the right DLPFC. Stimuli consisted of words related to the distinct emotion categories fear and anger as well as neutral words.ResultsTask accuracy increased for fear-related words and decreased for neutral words across stimulation conditions. No general state-dependent effects of prefrontal rTMS on working memory were found. We further showed a detrimental effect of negative emotional content on working memory performance.ConclusionsOur findings support a hemispheric lateralization of emotion processing by demonstrating that the withdrawal-related emotion fear is associated with the right DLPFC and contribute to clarifying the interaction between working memory and emotion.  相似文献   
979.
The miniature pig is an optimal animal model for studying nervous system disease because of its physiologic and pathologic features. However, the rete mirabile composed of arteries and veins at the skull base limits their application as a model of ischemic stroke by middle cerebral artery occlusion. The present study investigated the possibility of establishing an ischemic stroke model in the miniature pig by blocking the skull base retia with sodium alginate microspheres. Three Bama miniature pigs were used. Using the monitor of C-arm X-ray machine, sodium alginate microspheres (100-300 μm), a novel embolic material, were injected through the femoral artery, aortic arch, common carotid artery, ascending pharyngeal artery and the retia. Results were evaluated using carotid arteriography, MRI, behavior observation and histology. The unilateral rete mirabile was completely blocked, resulting in disturbance in blood supply to the basal ganglia, astasia of the right hind limb and salivation. MRI and hematoxylin-eosin staining showed an evident infarction focus in the basal ganglia. These findings indicate that sodium alginate microspheres are a suitable embolic material for blocking the skull base retia in miniature pigs to establish an ischemic stroke models.  相似文献   
980.
As a synthetic polypeptide water-soluble poly(l-glutamic acid) (PLGA) was designed to fabricate scaffolds for cartilage tissue engineering. Chitosan (CHI) has been employed as a physical cross-linking component in the construction of scaffolds. PLGA/CHI scaffolds act as sponges with a swelling ratio of 760 ± 45% (mass%), showing promising biocompatibility and biodegradation. Autologous adipose-derived stem cells (ASCs) were expanded and seeded on PLGA/CHI scaffolds, ASC/scaffold constructs were then subjected to chondrogenic induction in vitro for 2 weeks. The results showed that PLGA/CHI scaffolds could effectively support ASC adherence, proliferation and chondrogenic differentiation. The ASCs/scaffold constructs were then transplanted to repair full thickness articular cartilage defects (4 mm in diameter, to the depth of subchondral bone) created in rabbit femur trochlea. Histological observations found that articular defects were covered with newly formed cartilage 6 weeks post-implantation. After 12 weeks the regenerated cartilage had integrated well with the surrounding native cartilage and subchondral bone. Toluidine blue and immunohistochemical staining confirmed similar accumulation of glycosaminoglycans and type II collagen in engineered cartilage as in native cartilage 12 weeks post-implantation. The result was further supported by quantitative analysis of extracellular matrix deposition. The compressive modulus of the engineered cartilage increased significantly from 30% of that of normal cartilage at 6 weeks to 83% at 12 weeks. Cyto-nanoindentation also showed analogous biomechanical behavior of the engineered cartilage to that of native cartilage. The results of the present study thus demonstrate the potentiality of PLGA/CHI scaffolds in cartilage tissue engineering.  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