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   3289篇
  免费   145篇
  国内免费   17篇
耳鼻咽喉   62篇
儿科学   166篇
妇产科学   122篇
基础医学   352篇
口腔科学   92篇
临床医学   283篇
内科学   610篇
皮肤病学   103篇
神经病学   198篇
特种医学   102篇
外科学   583篇
综合类   64篇
一般理论   2篇
预防医学   134篇
眼科学   62篇
药学   300篇
中国医学   14篇
肿瘤学   202篇
  2024年   4篇
  2023年   31篇
  2022年   70篇
  2021年   158篇
  2020年   82篇
  2019年   127篇
  2018年   129篇
  2017年   90篇
  2016年   115篇
  2015年   127篇
  2014年   177篇
  2013年   188篇
  2012年   327篇
  2011年   336篇
  2010年   162篇
  2009年   134篇
  2008年   203篇
  2007年   141篇
  2006年   161篇
  2005年   161篇
  2004年   127篇
  2003年   104篇
  2002年   76篇
  2001年   21篇
  2000年   17篇
  1999年   18篇
  1998年   15篇
  1997年   7篇
  1996年   4篇
  1995年   6篇
  1994年   10篇
  1991年   11篇
  1990年   5篇
  1989年   7篇
  1988年   9篇
  1986年   8篇
  1985年   4篇
  1984年   6篇
  1982年   8篇
  1981年   4篇
  1980年   4篇
  1979年   3篇
  1978年   4篇
  1975年   4篇
  1974年   4篇
  1973年   4篇
  1972年   6篇
  1971年   4篇
  1970年   6篇
  1966年   4篇
排序方式: 共有3451条查询结果,搜索用时 15 毫秒
31.
Giant glomus tumors pose a challenge to the Otologist by virtue of their location and vascularity. A vast majority of them present with tinnitus, conductive hearing loss and cranial nerve palsies. We report the case of a 16-year-old male patient who presented with sudden right-sided sensorineural hearing loss. This is an unusual presentation of a giant glomus tumor. We present the clinical features and management of this unusual case.  相似文献   
32.
Midazolam, triazolam (TRZ), testosterone, and nifedipine have all been widely used as probes for in vitro metabolism of CYP3A. We used these four substrates to assess the contributions of CYP3A4 and CYP3A5 to in vitro biotransformation in human liver microsomes (HLMs) and in recombinant enzymes. Recombinant CYP3A4 and CYP3A5 (rCYP3A4 and rCYP3A5) both produced 1-OH and 4-OH metabolites from midazolam and triazolam, 6 beta-hydroxytestosterone from testosterone, and oxidized nifedipine from nifedipine. Overall, the metabolic activity of CYP3A5 was less than that of CYP3A4. Ketoconazole potently inhibited midazolam, triazolam, testosterone, and nifedipine metabolite formation in HLMs and in rCYP3A4. The inhibitory potency of ketoconazole in rCYP3A5 was about 5- to 19-fold less than rCYP3A4 for all four substrates. In testosterone interaction studies, testosterone inhibited 1-OH-TRZ formation, but significantly activated 4-OH-TRZ formation in HLMs and rCYP3A4 but not in rCYP3A5. Oxidized nifedipine formation was inhibited by testosterone in rCYP3A4. However, in rCYP3A5, testosterone slightly activated oxidized nifedipine formation at lower concentrations, followed by inhibition. Thus, CYP3A4 and CYP3A5 both contribute to midazolam, triazolam, testosterone, and nifedipine biotransformation in HLMs, with CYP3A5 being metabolically less active than CYP3A4 in general. Because the inhibitory potency of ketoconazole in rCYP3A5 is substantially less than in rCYP3A4 and HLMs, CYP3A5 is probably less important than CYP3A4 in drug-drug interactions involving ketoconazole and CYP3A substrates.  相似文献   
33.
34.
Electrophysiological correlates of sensory function in diabetic pregnancy have not been documented. Present study reports changes in Auditory evoked responses (AER) in gestational diabetics when compared with normal pregnant controls. Human AER are generally classified into early Auditory brainstem responses (AER), Mid latency responses (MLR) and late Slow vertex responses (SVR). These potentials were recorded in 20 women with diabetic pregnancy using Ag/AgCl electrodes from Cz-A1 and Cz-A2 position on MEB 5200 Neuropack II ... plus (Nihon Kohden, Japan) Evoked Potential Recorder. The evoked potentials in gestational diabetics were compared with 20 age matched normal pregnant women using Student's t-test. Absolute latencies of waves I to V, Inter peak latencies I-III and I-V of ABR were significantly increased whereas amplitude of wave V decreased in diabetic pregnant women. No significant change in latency of any component of MLR was observed between the two groups whereas significant prolongation of latencies of all components of SVR was observed in diabetic pregnant women as compared to normal control group. These findings indicate prolongation of both peripheral transmission time (PTT) and central transmission time (CTT) in diabetic pregnant females. Prolongation of latencies of SVR components in this study implicates cortex in the central diabetic neuropathy in women with gestational diabetes.  相似文献   
35.

The Garhwal Himalayas are a part of a unique ecosystem, with sharp agro-climatic variations within a very small geographical area (53,485 km2). The varied agro-climatic situations result in different cropping systems and socio-economic lifestyles that could likely affect the nutritional status of the people living in this region. This article will attempt to explore the impact of these variables (namely, age, family size, education, income, calorie and protein intake, land holding, number of animals, and wheat production) on the body mass index (BMI) of the population residing in the Garhwal Hills. A total of 1,030 subjects were studied from the three agro-climatic zones (406 from the high hills, 292 from the mid hills, and 332 from the low hills). It has been found that the people living in the high hills are the most undernourished, as the lowest percentage of people (52.6 per cent) with an acceptable BMI and the highest percentage of people in the severely malnourished category (11.1 per cent) are found here. People living in urban areas have a better nutritional status. Correlation studies show that the nutritional status of the population improves with age, literacy levels, and small family size. In some cases, calorie and protein intake have a positive impact on the health of the people, whereas size of land holding, number of animals, and income of the family do not have any significant influence on nutritional status.  相似文献   

36.
37.
Multichannel auditory brainstem implants (ABI) are currently indicated for patients with neurofibromatosis type II (NF2) involving both vestibulocochlear nerves. The ABI helps bypass the damaged cochlear nerves and restores a level of auditory sensation via the electrical stimulation of the cochlear nucleus. The implant is usually placed in the lateral recess of the fourth ventricle at the time of tumor resection to stimulate the cochlear nucleus. We report a case of ABI done on a 15-year-old girl with bilateral vestibular schwannomas.  相似文献   
38.
Several 1-(substituted phenoxy)-3-{[4-(4-trifluoromethyl) phenoxy] piperidin-1-yl} propan-2-ols (str.II) were prepared in a six-step reaction sequence starting from methylamine and ethyl acrylate and evaluated for antidepressant activity. The compounds were fully characterized by spectral and elemental analyses, and were tested for their effect on gross behavior, antireserpine and anorexigenic activity. No effect was observed on gross behavior and some of them showed fluoxetine like antireserpine and anorexigenic activity.  相似文献   
39.
The binding studies of Co(III) and Ru(II) polypyridyl complexes with dsDNA were carried out by molecular modeling studies to identify the binding interactions. The 3D structures of the metal complexes [Ru(phen)2ippip]2+ (RP-ippip), [Co(phen)2ippip]3+ (CP-ippip), [Ru(bpy)2ippip]2+ (RB-ippip), and [Co(bpy)2ippip]3+ (CB-ippip), where ippip = 4-(isopropylbenzaldehyde)imidazo[4,5-f][1,10] phenanthroline, phen = 1,10-phenanthroline, and bpy = bypyridine, were simulated using molecular dynamic simulations for stable conformers. The energy-minimized 3D structures of metal complexes were docked to the double-stranded dodecamer 5′-D(*AP * CP * CP * GP * AP * CP * GP * TP * CP * GP * GP * T)-3′. The aromatic ligand, ippip, facilitates the binding of the metal complex with DNA through intercalation. The effect of ancillary ligands, phen and bpy, was investigated. The ancillary ligands were found to be involved in bond formation with the phosphate backbone of nucleotide base pairs in metal complex–DNA docked complex. The significant interactions of metal complexes in the major groove of DNA are the prerequisite features of the metal complexes to be considered as DNA-intercalator. The molecular docking data are well substantiated by the available experimental data. The modeling results should extend knowledge about the nature of binding of these complexes with DNA.  相似文献   
40.
Aim To compare American Diabetes Association and International Expert Committee recommended cut‐off values of HbA1c for detecting the presence of pre‐diabetes against plasma glucose values obtained from oral glucose tolerance tests in Asian Indians. Methods A cross‐sectional randomly sampled population survey involving 2368 adults, aged ≥ 20 years. HbA1c was measured on a Bio‐Rad 10 system in 1972 subjects. Results Of the 1972 subjects studied, 329 were detected to have pre‐diabetes based on isolated impaired fasting glucose in 125 subjects (6.3%), isolated impaired glucose tolerance in 141 subjects (7.1%) and the presence of both in 63 subjects (3.2%). The HbA1c cut‐off of 34 mmol/mol (5.7%), as recommended by the American Diabetes Association for detecting the presence of pre‐diabetes, showed sensitivity of 62%, specificity 77%, with a positive predictive value of 34.7%, a negative predictive value of 89.5% and accuracy of 67.8%; whereas the HbA1c cut‐off recommended by the International Expert Committee of 42 mmol/mol (6%) had a sensitivity of 36%, specificity of 90%, positive predictive value of 42.7%, negative predictive of 85.4% and an accuracy of 77%. However, both these HbA1c cut‐offs underdiagnosed the presence of pre‐diabetes in 38 and 64% of these subjects, respectively. Conclusions The American Diabetes Association and the International Expert Committee recommended HbA1c cut‐off values and oral glucose tolerance tests identify different pre‐diabetes cohorts. Long‐term prospective studies are required to define the usefulness of one over the other.  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