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   639篇
  免费   23篇
  国内免费   47篇
耳鼻咽喉   4篇
儿科学   21篇
妇产科学   26篇
基础医学   57篇
口腔科学   21篇
临床医学   75篇
内科学   87篇
皮肤病学   8篇
神经病学   31篇
特种医学   172篇
外科学   24篇
综合类   20篇
预防医学   55篇
药学   48篇
中国医学   1篇
肿瘤学   59篇
  2022年   3篇
  2021年   6篇
  2020年   3篇
  2018年   4篇
  2017年   9篇
  2016年   8篇
  2015年   33篇
  2014年   33篇
  2013年   69篇
  2012年   18篇
  2011年   16篇
  2010年   21篇
  2009年   20篇
  2008年   7篇
  2007年   41篇
  2006年   8篇
  2005年   11篇
  2004年   13篇
  2003年   11篇
  2002年   13篇
  2001年   10篇
  2000年   15篇
  1999年   13篇
  1998年   21篇
  1997年   25篇
  1996年   16篇
  1995年   22篇
  1994年   19篇
  1993年   15篇
  1992年   9篇
  1991年   10篇
  1990年   12篇
  1989年   18篇
  1988年   14篇
  1987年   11篇
  1986年   8篇
  1985年   7篇
  1984年   8篇
  1983年   9篇
  1982年   8篇
  1981年   5篇
  1980年   7篇
  1976年   10篇
  1975年   3篇
  1971年   3篇
  1968年   3篇
  1949年   4篇
  1948年   3篇
  1947年   6篇
  1908年   2篇
排序方式: 共有709条查询结果,搜索用时 0 毫秒
51.
宁国贝母生物碱的分离和结构鉴定   总被引:2,自引:0,他引:2  
从贝母新种——宁国贝母(Fritillaria ningguoensis S. C. Chen et S. F. Yin)鳞茎中分离出五个生物碱,其中碱V是一种新的生物碱,命名为宁贝新(ningpeisine),根据理化常数和光谱解析以及衍生物制备,测定其结构为N-methyl-3β-hydroxy-5α-veratranine-6-one。其余四种生物碱鉴定为浙贝甲素(peimine,verticine,Ⅰ),浙贝乙素(peiminine,verticinone,Ⅱ),异浙贝甲素(isoverticine,Ⅲ)和贝母辛(peimisine,Ⅳ)。  相似文献   
52.
Insulin monomers and polymers were analysed by quantitative immunoelectrophoretic procedures. The Zn-insulin hexamer dissociated reversibly by dialysis against the Zn-free electrophoresis buffer. The Zn-insulin polymers showed precipitin reactions of partial identity. Monomeric salt-free insulin migrated as soluble immune complexes in the antiserum gel. The insulin monomer did not absorb the precipitating antibodies against the Zn-insulin polymers. Thus the polymer structure creates antigenic epitopes absent from the insulin monomer. As insulin is probably released from the β cells in the relatively stable form of Zn-insulin hexamers, selective monomer assays might underestimate the total content of immunoreactive insulin in the biological fluids. Electroimmunoassay of Zn-insulin immunoreactive antigens in human urine defines a normal reference range of 10–25 ng/ml.  相似文献   
53.
ABSTRACT. Longitudinal bone growth in rabbits during treatment with hydrocortisone was measured by means of Roentgen Stereophotogrammetric Analysis, RSA. This method allows accurate measurement of the distance between metallic markers inserted into long bones. Hydrocortisone was given in i.m. injections as single doses and as repeated doses, daily or every other day. Single injections of hydrocortisone resulted in three types of growth effect, depending on dosage. Low dosage (less than 4 mg/kg b.w.) produced no blunting of growth. Intermediate dosage (4–32 mg/kg b.w.) retarded growth during the first but not the second day after the injection. The effect of high dosage (64–128 mg/kg b.w.) lasted for two days. During daily treatment (4 and 16 mg/kg b.w.), growth decreased to a constant level. During alternate-day steroid injections with a double dose every other day, growth almost normalized during the steroid-free days. Average growth was significantly greater during alternate-day injections than during daily injections. It is concluded that alternate-day treatment has no unfavorable effect on growth so long as the interval between injections exceeds the duration of the growth effect of each single dose.  相似文献   
54.
Investigations were made of 16 patients with acquired pendular nystagmus and a further 32 cases reported in the literature were reviewed. Amongst our own patients two thirds had multiple sclerosis, almost one third a cerebrovascular accident or angioma and two had optic atrophy with squint. The nystagmus took forms which could be monocular or binocular, conjugate or disconjugate and could involve movements about single or multiple axes. Spectral analysis was used to characterise the amplitude and frequency of the movements and to estimate the degree of relationship (coherence) between movements of the two eyes or between movements of one eye about several axes. The oscillations ranged in frequency from 2·5 Hz to 6 Hz, with typical amplitudes between 3° and 5°. In a given patient all oscillations, regardless of plane, were highly synchronised. Somatic tremors of the upper limb, face and palate associated with the nystagmus were often at similar frequencies to the eye movement. The other ocular signs common to all our patients were the presence of squint with failure of convergence. Most patients also had skew deviation or internuclear ophthalmoplegia or both. The major oculomotor systems, that is, saccades, pursuit, optokinetic and vestibulo-ocular reflexes could be intact. It is inferred that the mechanism responsible for the pendular nystagmus lies at a level which is close to the oculomotor nuclei so that it can have monocular effects but is not part of the primary motor pathways. It is possible that this mechanism normally subserves maintenance of conjugate movement and posture of the eyes. The periodicity of the nystagmus is likely to arise from instability in a certain type(s) of neurone, for the associated somatic tremors have similar characteristics and yet involve very different neuronal muscular circuitry. Prognosis for cessation of the nystagmus is poor. In five patients with multiple sclerosis it was suppressed by intravenous hyoscine with, however, unacceptable subsequent side effects.  相似文献   
55.
56.
The orbital apex, formed by the superior orbital fissure and optic canal, is the cross-road between the orbit and the intracranial structures. Pathological processes may extend intracranially via the superior orbital fissure and vice versa. In addition to intrinsic soft tissue lesions, various pathological processes may involve the surrounding osseous anatomy. Malignant lesions arising from adjacent structures or from haematogeneous metastasis may also infiltrate this region.  相似文献   
57.
急性淋巴细胞白血病(上)   总被引:2,自引:0,他引:2  
急性淋巴细胞白血病是淋巴前体细胞异常引起的恶性疾病,儿童与成人均可能发生。儿童发病高峰2~5岁。有效治疗的稳步进展使本病在儿童中的治愈率80%以上,同时为新的治疗方案提供了良机,新方案将保留我们在白血病无病生存病例中获得的治疗经验,同时减轻当前强化治疗方案中的毒副作用。  相似文献   
58.
Human immunodeficiency virus‐related oral lesions (HIV‐OLs), such as oral candidiasis (OC) and oral hairy leukoplakia (OHL), have been recognized as indicators of immune suppression since the beginning of the global HIV epidemic. The diagnosis and management of HIV disease and spectrum of opportunistic infection has changed over the past 30 years as our understanding of the infection has evolved. We investigated the following controversial topics: (i) Are oral manifestations of HIV still relevant after the introduction of highly active antiretroviral therapy (HAART)? (ii) Can we nowadays still diagnose HIV infection through oral lesions? (iii) Is the actual classification of oral manifestations of HIV adequate or does it need to be reviewed and updated? (iv) Is there any novelty in the treatment of oral manifestations of HIV infection? Results from extensive literature review suggested the following: (i) While HAART has resulted in significant reductions in HIV‐OLs, many are still seen in patients with HIV infection, with OC remaining the most common lesion. While the relationship between oral warts and the immune reconstitution inflammatory syndrome is less clear, the malignant potential of oral human papillomavirus infection is gaining increasing attention. (ii) Effective antiretroviral therapy has transformed HIV from a fatal illness to a chronic manageable condition and as a result expanded screening policies for HIV are being advocated both in developed and in developing countries. Affordable, reliable, and easy‐to‐use diagnostic techniques have been recently introduced likely restricting the importance of HIV‐OLs in diagnosis. (iii) The 1993 EC‐Clearinghouse classification of HIV‐OLs is still globally used despite controversy on the relevance of periodontal diseases today. HIV‐OL case definitions were updated in 2009 to facilitate the accuracy of HIV‐OL diagnoses by non‐dental healthcare workers in large‐scale epidemiologic studies and clinical trials. (iv) Research over the last 6 years on novel modalities for the treatment of HIV‐OLs has been reported for OC and OHL.  相似文献   
59.
目的探讨冠心病(CHD)患者实施健康信念模式干预的效果。方法将140例CHD患者随机分对照组和干预组,各70例,对照组给予常规治疗和护理,干预组在对照组的基础上给予健康信念模式干预措施;比较两组的遵医行为、干预效果及生活质量评分。结果实施干预后,干预组的遵医行为备维度得分均明显好于对照组(P〈0.0.01);干预组的各干预效果指标均明显好于对照组(P〈0.05):干预组的生活质量各维度指标也明显好于对照组(P〈0.01)。结论CHD患者实施健康信念模式干预后,明显提高CHD患者的遵医行为和生活质量评分,干预效果明显。  相似文献   
60.
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