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   6571篇
  免费   383篇
  国内免费   32篇
耳鼻咽喉   55篇
儿科学   110篇
妇产科学   113篇
基础医学   933篇
口腔科学   100篇
临床医学   599篇
内科学   1126篇
皮肤病学   351篇
神经病学   746篇
特种医学   359篇
外科学   891篇
综合类   54篇
预防医学   318篇
眼科学   120篇
药学   506篇
中国医学   29篇
肿瘤学   576篇
  2023年   36篇
  2022年   26篇
  2021年   101篇
  2020年   83篇
  2019年   98篇
  2018年   134篇
  2017年   130篇
  2016年   159篇
  2015年   210篇
  2014年   242篇
  2013年   278篇
  2012年   445篇
  2011年   441篇
  2010年   306篇
  2009年   282篇
  2008年   471篇
  2007年   495篇
  2006年   491篇
  2005年   473篇
  2004年   419篇
  2003年   425篇
  2002年   430篇
  2001年   86篇
  2000年   49篇
  1999年   79篇
  1998年   89篇
  1997年   68篇
  1996年   50篇
  1995年   39篇
  1994年   44篇
  1993年   39篇
  1992年   26篇
  1991年   9篇
  1990年   17篇
  1989年   16篇
  1988年   13篇
  1987年   11篇
  1986年   12篇
  1985年   9篇
  1984年   9篇
  1983年   8篇
  1982年   10篇
  1981年   10篇
  1980年   19篇
  1979年   7篇
  1978年   13篇
  1977年   10篇
  1976年   12篇
  1975年   7篇
  1973年   7篇
排序方式: 共有6986条查询结果,搜索用时 218 毫秒
1.
2.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz -  相似文献   
3.
Journal of Neuro-Oncology - Evidence supporting routine postoperative antiepileptic drug (AED) prophylaxis following oncologic neurosurgery is limited, and actual practice patterns are largely...  相似文献   
4.
ABSTRACT

Objectives: The consequences of polypharmacy (intake of ≥ 5 drugs) are diverse, including drug interactions, rising costs and side effects. Risk groups for polypharmacy are multimorbid and chronically ill people, such as patients with multiple sclerosis (MS). MS is the most common neuroimmunological disease in young adults worldwide. We aimed to provide a systematic overview of the current research status regarding frequency and predictors of polypharmacy in MS patients.

Methods: A systematic literature search in the databases PubMed, Cochrane Library and Scopus was carried out according to the PRISMA guidelines. English and German original research articles were included.

Results: Seven studies fulfilled the inclusion criteria of this review, while the research objectives and methods were very heterogenous. The polypharmacy rates in these studies ranged from 15% to 59%. Polypharmacy correlated with comorbidities, increased disability, cognitive deficits, increased hospitalization, higher relapse rate and lower quality of life.

Conclusions: In MS patients, polypharmacy is common and closely associated with health issues. There is a great need for research in this area, especially regarding longitudinal changes in drug utilization. Effective networks between physicians and pharmacists are needed to optimize medication management for patients and to achieve the best possible therapy results.  相似文献   
5.
Klawitter  Felix  Walter  Uwe  Axer  Hubertus  Ehler  Johannes 《Der Anaesthesist》2023,72(8):543-554
Die Anaesthesiologie - Die Intensive Care Unit-Acquired Weakness (ICUAW) stellt eine der häufigsten neuromuskulären Komplikationen in der Intensivmedizin dar. Besonders bei...  相似文献   
6.

Background and purpose

Evidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor.

Materials and methods

Sixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n?=?49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n?=?29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA).

Results

Motor group: paretic patients showed significantly (P?=?0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P?<?0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r?=?0.68, P?<?0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P?=?0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r?=?0.72, P?<?0.01) between BA 44 BOLD signal and phonological fluency performance was observed.

Conclusions

Our results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients.  相似文献   
7.
The central complex (CX) comprises a group of midline neuropils in the insect brain, consisting of the protocerebral bridge (PB), the upper (CBU) and lower division (CBL) of the central body and a pair of globular noduli. It receives prominent input from the visual system and plays a major role in spatial orientation of the animals. Vertical slices and horizontal layers of the CX are formed by columnar, tangential, and pontine neurons. While pontine and columnar neurons have been analyzed in detail, especially in the fruit fly and desert locust, understanding of the organization of tangential cells is still rudimentary. As a basis for future functional studies, we have studied the morphologies of tangential neurons of the CX of the desert locust Schistocerca gregaria. Intracellular dye injections revealed 43 different types of tangential neuron, 8 of the PB, 5 of the CBL, 24 of the CBU, 2 of the noduli, and 4 innervating multiple substructures. Cell bodies of these neurons were located in 11 different clusters in the cell body rind. Judging from the presence of fine versus beaded terminals, the vast majority of these neurons provide input into the CX, especially from the lateral complex (LX), the superior protocerebrum, the posterior slope, and other surrounding brain areas, but not directly from the mushroom bodies. Connections are largely subunit- and partly layer-specific. No direct connections were found between the CBU and the CBL. Instead, both subdivisions are connected in parallel with the PB and distinct layers of the noduli.  相似文献   
8.
The resistant and recalcitrant nature of severe allergic contact dermatitis (ACD) makes its management challenging. With advances in the understanding of the cellular and molecular pathogenesis of ACD, newer therapeutic targets are becoming apparent. In particular, the use of biologics has gained momentum, given the specificity of their action. This article aims to review the presently available data on the use of biologics in ACD. English-language–based literature available on the use of biological therapy was thoroughly probed in the following databases as on October 14, 2019: PubMed, Google Scholar, The Cochrane library, Embase, Scopus, and EBSCO. The following keywords were used: “contact dermatitis”, “allergens”, “delayed-type hypersensitivity reaction”, “biologics”, “biological therapy”, “monoclonal antibodies”, “patch testing”, “TNF-α inhibitors”, “infliximab”, “adalimumab”, “etanercept”, “dupilumab”, “omalizumab”, “secukinumab”, “ustekinumab”, “rituximab”.  相似文献   
9.
10.
Tissue characterization in brain tumors and, in particular, in high‐grade gliomas is challenging as a result of the co‐existence of several intra‐tumoral tissue types within the same region and the high spatial heterogeneity. This study presents a method for the detection of the relevant tumor substructures (i.e. viable tumor, necrosis and edema), which could be of added value for the diagnosis, treatment planning and follow‐up of individual patients. Twenty‐four patients with glioma [10 low‐grade gliomas (LGGs), 14 high‐grade gliomas (HGGs)] underwent a multi‐parametric MRI (MP‐MRI) scheme, including conventional MRI (cMRI), perfusion‐weighted imaging (PWI), diffusion kurtosis imaging (DKI) and short‐TE 1H MRSI. MP‐MRI parameters were derived: T2, T1 + contrast, fluid‐attenuated inversion recovery (FLAIR), relative cerebral blood volume (rCBV), mean diffusivity (MD), fractional anisotropy (FA), mean kurtosis (MK) and the principal metabolites lipids (Lip), lactate (Lac), N‐acetyl‐aspartate (NAA), total choline (Cho), etc. Hierarchical non‐negative matrix factorization (hNMF) was applied to the MP‐MRI parameters, providing tissue characterization on a patient‐by‐patient and voxel‐by‐voxel basis. Tissue‐specific patterns were obtained and the spatial distribution of each tissue type was visualized by means of abundance maps. Dice scores were calculated by comparing tissue segmentation derived from hNMF with the manual segmentation by a radiologist. Correlation coefficients were calculated between each pathologic tissue source and the average feature vector within the corresponding tissue region. For the patients with HGG, mean Dice scores of 78%, 85% and 83% were obtained for viable tumor, the tumor core and the complete tumor region. The mean correlation coefficients were 0.91 for tumor, 0.97 for necrosis and 0.96 for edema. For the patients with LGG, a mean Dice score of 85% and mean correlation coefficient of 0.95 were found for the tumor region. hNMF was also applied to reduced MRI datasets, showing the added value of individual MRI modalities. Copyright © 2015 John Wiley & Sons, Ltd.  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