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   3125篇
  免费   284篇
  国内免费   27篇
耳鼻咽喉   20篇
儿科学   99篇
妇产科学   80篇
基础医学   376篇
口腔科学   198篇
临床医学   301篇
内科学   546篇
皮肤病学   58篇
神经病学   344篇
特种医学   137篇
外科学   387篇
综合类   76篇
预防医学   354篇
眼科学   99篇
药学   237篇
中国医学   1篇
肿瘤学   123篇
  2021年   47篇
  2020年   27篇
  2019年   43篇
  2018年   55篇
  2017年   44篇
  2016年   30篇
  2015年   45篇
  2014年   58篇
  2013年   82篇
  2012年   111篇
  2011年   156篇
  2010年   76篇
  2009年   73篇
  2008年   95篇
  2007年   137篇
  2006年   120篇
  2005年   124篇
  2004年   111篇
  2003年   99篇
  2002年   105篇
  2001年   72篇
  2000年   84篇
  1999年   88篇
  1998年   50篇
  1997年   45篇
  1996年   37篇
  1995年   45篇
  1994年   34篇
  1993年   30篇
  1992年   73篇
  1991年   49篇
  1990年   61篇
  1989年   76篇
  1988年   63篇
  1987年   69篇
  1986年   83篇
  1985年   69篇
  1984年   54篇
  1983年   56篇
  1982年   34篇
  1981年   31篇
  1979年   53篇
  1978年   45篇
  1977年   43篇
  1976年   42篇
  1974年   35篇
  1973年   38篇
  1971年   28篇
  1970年   31篇
  1969年   39篇
排序方式: 共有3436条查询结果,搜索用时 0 毫秒
41.
A series of 154 allergic patients were treated with Vistaril. The drug was effective in allergic rhinitis, urticaria, and pruritus of any allergic cause. It was not effective in asthma. Vistaril has a wide spectrum of action and had a high degree of patient acceptance. Duration of action in most cases was 8 to 10 hours or more. The main side effect was drowsiness. Serious side effects were not encountered.  相似文献   
42.
43.
Helicobacter pylori is a globally important and genetically diverse gastric pathogen that infects most people in developing countries. Eradication efforts are complicated by antibiotic resistance, which varies in frequency geographically. There are very few data on resistance in African strains. Sixty-four Gambian H. pylori strains were tested for antibiotic susceptibility. The role of rdxA in metronidazole (Mtz) susceptibility was tested by DNA transformation and sequencing; RdxA protein variants were interpreted in terms of RdxA structure. Forty-four strains (69%) were resistant to at least 8 μg of Mtz/ml. All six strains from infants, but only 24% of strains from adults, were sensitive (P = 0.0031). Representative Mtz-resistant (Mtzr) strains were rendered Mtz susceptible (Mtzs) by transformation with a functional rdxA gene; conversely, Mtzs strains were rendered Mtzr by rdxA inactivation. Many mutations were found by Gambian H. pylorirdxA sequencing; mutations that probably inactivated rdxA in Mtzr strains were identified and explained using RdxA protein''s structure. All of the strains were sensitive to clarithromycin and erythromycin. Amoxicillin and tetracycline resistance was rare. Sequence analysis indicated that most tetracycline resistance, when found, was not due to 16S rRNA gene mutations. These data suggest caution in the use of Mtz-based therapies in The Gambia. The increasing use of macrolides against respiratory infections in The Gambia calls for continued antibiotic susceptibility monitoring. The rich variety of rdxA mutations that we found will be useful in further structure-function studies of RdxA, the enzyme responsible for Mtz susceptibility in this important pathogen.  相似文献   
44.
45.
Joslyn  JN; Mirvis  SE; Markowitz  B 《Radiology》1988,166(3):817-821
During a 20-month period, fractures of the clivus occurring after craniocerebral trauma were diagnosed with computed tomography (CT) in 11 patients. Five patients had longitudinally oriented fractures; these were fatal in four patients due to either vertebral-basilar artery occlusion, brain stem trauma, or both. Six other patients had transversely oriented fractures that extended through the carotid canal and petrous temporal bone. While less frequently contributing directly to mortality, transverse fractures were also associated with cerebrospinal fluid leaks (two patients) and a cavernous sinus-carotid fistula (one patient). They were not as frequently associated with Horner syndrome or cranial nerve deficits as suggested in the current literature. This retrospective evaluation reveals two distinct injury patterns that demonstrate a difference in related morbidity and mortality.  相似文献   
46.
47.

Purpose

This scoping review assesses the literature and summarizes the current evidence on sclerotherapy for the treatment of lymphatic malformations in pediatric patients.

Methods

A comprehensive search of published and unpublished literature was conducted using multiple databases. Title, abstract, and full-text screening was conducted by 2 independent clinicians. All discrepancies were resolved during consensus meetings.

Results

A total of 182 articles were retrieved. Forty-four articles were removed as duplicates, and 11 articles were added after reviewing prominent studies. After full-text abstraction, 44 articles and 2 conference proceedings (N = 882 patients) were included in the final results. Twelve articles were classified as level II and 34 articles as level IV evidence. Picibanil (OK-432) was the primary agent used in most included studies. Postinjection symptoms with OK-432 were primarily fever, swelling, and erythema at the site. Life-threatening complications were uncommon and involved postinjection swelling of cervical lesions causing airway compromise.

Conclusions

The literature regarding sclerotherapy for lymphatic malformations is of a low level of evidence and suffers from a lack of standardization. Randomized clinical trials focused on OK-432, bleomycin, or alcoholic solution of zein; standardized dosing protocols; and consistent and reliable outcome reporting will be necessary for further development of treatment guidelines.  相似文献   
48.
Background

The purpose of this consensus guideline is to outline recommendations for genetic testing that medical professionals can use to assess hereditary risk for breast cancer.

Methods

Literature review included large datasets, basic and clinical science publications, and recent updated national guidelines. Genetic testing to assess hereditary risk of cancer is a complex, broad, and dynamic area of medical research. The dominant focus of this guideline is limited in scope to breast cancer.

Results

There is a lack of consensus among experts regarding which genes among many should be tested in different clinical scenarios. There is also variation in the degree of consensus regarding the understanding of risk and appropriate clinical management of mutations in many genes.

Conclusions

Genetic testing should be made available to all patients with a personal history of breast cancer. Recent data are reviewed that support genetic testing being offered to each patient with breast cancer (newly diagnosed or with a personal history). If genetic testing is performed, such testing should include BRCA1/BRCA2 and PALB2, with other genes as appropriate for the clinical scenario and family history. For patients with newly diagnosed breast cancer, identification of a mutation may impact local treatment recommendations. Patients who had genetic testing previously may benefit from updated testing. Genetic testing should be made available to patients without a history of breast cancer who meet National Comprehensive Cancer Network guidelines. Finally, variants of uncertain significance are not clinically actionable and these patients should be managed based on their individual risk factors.

  相似文献   
49.
PurposeMucous fistula (MF) refeeding of proximal stoma effluent in neonates after small bowel resection can promote nutrient absorption and prevent atrophy of the unused distal bowel. This study aimed to assess the safety of this practice in neonates.MethodsA retrospective chart review of all patients admitted to the neonatal intensive care unit (NICU) between 2009 and 2015 who underwent a laparotomy with creation of an enterostomy and mucous fistula was performed. Patients were included if they were refed proximal stoma effluent into the MF.ResultsThirty-one patients were identified that were refed. There were no major complications (perforation, stricture, death) related to refeeding. Patients were refed for an average of 41 days (± 22), with patients gaining an average of 25.7 g/day (± 10.1) while being refed. Total parental nutrition (TPN) was administered for an average of 55 days (± 31.4) between resection and reanastomosis, with only 7 (23%) developing cholestasis and 15 (48%) reaching full feeds in this time. Mean time to full feeds after reanastomosis was 36 days (± 58.6) with two patients having anastomotic leaks.ConclusionMF refeeding is a safe technique that has the potential to contribute to significant weight gain and a decreased dependence on total parenteral nutrition.Level of evidenceII  相似文献   
50.
Given the difficulty of procuring human brain tissue, a key question in molecular psychiatry concerns the extent to which epigenetic signatures measured in more accessible tissues such as blood can serve as a surrogate marker for the brain. Here, we aimed (1) to investigate the blood-brain correspondence of DNA methylation using a within-subject design and (2) to identify changes in DNA methylation of brain-related biological pathways in schizophrenia.We obtained paired blood and temporal lobe biopsy samples simultaneously from 12 epilepsy patients during neurosurgical treatment. Using the Infinium 450K methylation array we calculated similarity of blood and brain DNA methylation for each individual separately. We applied our findings by performing gene set enrichment analyses (GSEA) of peripheral blood DNA methylation data (Infinium 27K) of 111 schizophrenia patients and 122 healthy controls and included only Cytosine-phosphate-Guanine (CpG) sites that were significantly correlated across tissues.Only 7.9% of CpG sites showed a statistically significant, large correlation between blood and brain tissue, a proportion that although small was significantly greater than predicted by chance. GSEA analysis of schizophrenia data revealed altered methylation profiles in pathways related to precursor metabolites and signaling peptides.Our findings indicate that most DNA methylation markers in peripheral blood do not reliably predict brain DNA methylation status. However, a subset of peripheral data may proxy methylation status of brain tissue. Restricting the analysis to these markers can identify meaningful epigenetic differences in schizophrenia and potentially other brain disorders.Key words: DNA methylation, cross-tissue, blood, brain, correlation, schizophrenia  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