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   4591篇
  免费   303篇
  国内免费   117篇
耳鼻咽喉   21篇
儿科学   239篇
妇产科学   179篇
基础医学   523篇
口腔科学   131篇
临床医学   525篇
内科学   910篇
皮肤病学   141篇
神经病学   217篇
特种医学   303篇
外科学   644篇
综合类   132篇
预防医学   242篇
眼科学   140篇
药学   328篇
中国医学   32篇
肿瘤学   304篇
  2023年   35篇
  2022年   35篇
  2021年   131篇
  2020年   74篇
  2019年   87篇
  2018年   104篇
  2017年   91篇
  2016年   83篇
  2015年   97篇
  2014年   149篇
  2013年   160篇
  2012年   252篇
  2011年   279篇
  2010年   174篇
  2009年   171篇
  2008年   182篇
  2007年   253篇
  2006年   199篇
  2005年   209篇
  2004年   166篇
  2003年   141篇
  2002年   151篇
  2001年   168篇
  2000年   144篇
  1999年   117篇
  1998年   74篇
  1997年   75篇
  1996年   68篇
  1995年   70篇
  1994年   57篇
  1993年   47篇
  1992年   71篇
  1991年   53篇
  1990年   63篇
  1989年   70篇
  1988年   68篇
  1987年   72篇
  1986年   67篇
  1985年   43篇
  1984年   29篇
  1983年   29篇
  1982年   24篇
  1981年   24篇
  1979年   22篇
  1978年   17篇
  1977年   21篇
  1976年   22篇
  1975年   14篇
  1973年   16篇
  1959年   13篇
排序方式: 共有5011条查询结果,搜索用时 31 毫秒
101.

OBJECTIVE:

To summarize current Canadian practice patterns in the diagnosis of and interventions for inhalation injuries (INHI).

METHODS:

A 10-question survey regarding the diagnosis of and interventions for INHI was sent to the medical directors of all 16 burn centres across Canada.

RESULTS:

The response rate to the survey was 50%. Fibreoptic bronchoscopy is required for the diagnosis of INHI in only four centres (50%). The departments of intensive care, plastic surgery, otolaryngology and respirology are involved in performing fibreoptic bronchoscopy in 87.5%, 37.5%, 12.5% and 12.5% of Canadian burn centres, respectively. Intubation for INHI is most often based on physical examination results (87.5%) and clinical history (75%). The most common physical features believed to be most consistent with INHI are dyspnea (87.5%) and hoarseness (87.5%). Common treatments include intubation (87.5%), routine ventilatory support (87.5%) and chest physiotherapy (75%). None of the centres used nebulized heparin. A total of five centres (62.5%) routinely changed the fluid resuscitation protocol when INHI was diagnosed. Only two centres (25%) routinely used prophylactic antibiotics for INHI.

CONCLUSION:

Prospective, multicentre trials are needed to generate evidence-based consensus in the areas of diagnosis, grading and treatment for INHI in Canada.  相似文献   
102.
The United States Department of Health and Human Services (HHS) leads the nation in preventing, preparing for, and responding to the adverse health effects of public health emergencies and disasters. In addition to biological, radiological and nuclear agents, the risk of a high consequence public health emergency due to the intentional and/or accidental release of chemical agents is a major growing concern of the US government. As such, the federal government is fully committed to address public health security threats posed by chemicals. To enhance chemical emergency preparedness and response, HHS oversees the interdepartmental research, advanced development, regulatory review and approval, procurement, and stockpiling of medical countermeasures (MCMs). Within the National Institute of Health (NIH/HHS), the National Institute of Allergy and Infectious Diseases (NIAID) is responsible for the fundamental research and early development of MCMs to prevent deaths and/or treat injuries during and after emergencies due to large scale chemical exposure. This commentary provides an overview of the NIAID/NIH Chemical Countermeasures Research Program (CCRP) and resources to facilitate the research, discovery, and early development of chemical MCMs. Available product development resources include research funding opportunities, expert advice from the NIH, and preclinical and efficacy service support cores to reduce opportunity costs and entry barriers for prospective developers interested in entering or accelerating the development of chemical MCMs.  相似文献   
103.
BACKGROUND: Heterotrimeric G proteins take part in membrane-mediated cell signalling and have a role in hormonal regulation. This study clarifies the expression and localization of the G protein subunit G alpha(i2) in the human endometrium and Fallopian tube and changes in G alpha(i2) expression in human endometrium during the menstrual cycle. METHODS: The expression of G alpha(i2) was identified by Polymerase chain reaction (PCR), and localization confirmed by immunostaining. Cyclic changes in G alpha(i2) expression during the menstrual cycle were evaluated by quantitative real-time PCR. RESULTS: We found G alpha(i2) to be expressed in human endometrium, Fallopian tube tissue and in primary cultures of Fallopian tube epithelial cells. Our studies revealed enriched localization of G alpha(i2) in Fallopian tube cilia and in endometrial glands. We showed that G alpha(i2) expression in human endometrium changes significantly during the menstrual cycle, with a higher level in the secretory versus proliferative and menstrual phases (P < 0.05). CONCLUSIONS: G alpha(i2) is specifically localized in human Fallopian tube epithelial cells, particularly in the cilia, and is likely to have a cilia-specific role in reproduction. Significantly variable expression of G alpha(i2) during the menstrual cycle suggests G alpha(i2) might be under hormonal regulation in the female reproductive tract in vivo.  相似文献   
104.

Background

The Leukemia/Bone Marrow Transplant Program of British Columbia manages patients with high-risk febrile neutropenia and those with non-neutropenic immunocompromised states in an outpatient clinic setting. Because the program treats outpatients only, once-daily administration of IV antibiotics is desirable. A high-dose, once-daily vancomycin nomogram was developed and implemented as part of the antibiotic treatment regimen.

Objective:

To determine if therapeutic vancomycin trough levels could be achieved with a high-dose, once-daily regimen in this outpatient setting.

Methods:

A prospective, single-centre, observational cohort study was conducted over a 7-month period. Outpatients in the Leukemia/Bone Marrow Transplant Program were started on IV vancomycin with the high-dose, once-daily vancomycin nomogram, and outcomes were assessed.

Results:

Of 48 outpatients treated over the 7-month period, 10 (21%) had therapeutic vancomycin trough concentrations (i.e., greater than 10 mg/L). Thirty-five (90%) of the 39 patients with suspected clinical infection experienced clinical cure, and 6 (67%) of the 9 patients with documented microbiological infection experienced microbiological cure. Thirty (62%) of the 48 patients experienced symptoms of “red man syndrome”, and 7 (15%) experienced some degree of nephrotoxicity. Two of 3 patients with laboratory-reported minimum inhibitory concentration (MIC) for identified pathogens had a calculated area under the curve to MIC ratio greater than or equal to 400.

Conclusion:

The high-dose, once-daily vancomycin nomogram was effective in attaining trough levels greater than 10 mg/L in only 21% of patients in this study. A substantial number of adverse drug reactions were observed. Given these results, high-dose, once-daily vancomycin is no longer recommended for outpatient therapy.  相似文献   
105.
106.
107.
108.
109.
Two new wide bandgap block copolymers (PL1 and PL2) with porphyrin‐incorporated side chains are designed and used as electron donors for solution‐processed bulk heterojunction polymer solar cells. The photophysical, electrochemical, and photovoltaic properties, charge transport mobility and film morphology of these two block copolymers are investigated. Detailed investigations reveal that the different alkyl groups and electron‐withdrawing substituents on the porphyrin pendant units have significant influence on the polymer solubility, absorption energy level, band gap, and charge separation in the bulk‐heterojunction thin films, and thus the overall photovoltaic performances. Organic photovoltaic devices derived from these copolymers and ([6,6]‐phenyl‐C71‐butyric acid methyl ester) (PC71BM) acceptor show the best power conversion efficiencies of 5.83% and 7.14%, respectively. These results show that the inclusion of a certain proportion of side chain porphyrin group as a pendant in the traditional donor‐acceptor (D‐A) type polymer can broaden the molecular absorption range and become a full‐color absorbing molecule. The size of the porphyrin pendant also has an obvious effect on the properties of the molecule.  相似文献   
110.
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