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   2431篇
  免费   245篇
  国内免费   12篇
耳鼻咽喉   14篇
儿科学   99篇
妇产科学   19篇
基础医学   273篇
口腔科学   71篇
临床医学   259篇
内科学   499篇
皮肤病学   87篇
神经病学   215篇
特种医学   50篇
外科学   486篇
综合类   57篇
一般理论   5篇
预防医学   145篇
眼科学   120篇
药学   132篇
中国医学   4篇
肿瘤学   153篇
  2023年   13篇
  2022年   26篇
  2021年   62篇
  2020年   42篇
  2019年   70篇
  2018年   59篇
  2017年   49篇
  2016年   46篇
  2015年   61篇
  2014年   79篇
  2013年   88篇
  2012年   127篇
  2011年   141篇
  2010年   92篇
  2009年   68篇
  2008年   132篇
  2007年   161篇
  2006年   142篇
  2005年   162篇
  2004年   146篇
  2003年   124篇
  2002年   121篇
  2001年   24篇
  2000年   19篇
  1999年   24篇
  1998年   28篇
  1997年   24篇
  1996年   21篇
  1995年   19篇
  1994年   16篇
  1992年   22篇
  1990年   17篇
  1989年   24篇
  1988年   17篇
  1987年   16篇
  1986年   29篇
  1984年   16篇
  1983年   29篇
  1982年   17篇
  1981年   22篇
  1980年   12篇
  1977年   14篇
  1975年   16篇
  1974年   16篇
  1973年   11篇
  1965年   11篇
  1963年   12篇
  1962年   12篇
  1961年   14篇
  1960年   21篇
排序方式: 共有2688条查询结果,搜索用时 31 毫秒
81.
Effects of Hepatitis C on total hip (THA) and total knee arthroplasty (TKA) outcomes are poorly understood. Seventy-two hepatitis C patients underwent 77 primary THA or TKA and were retrospectively identified, stratified by fibrosis and thrombocytopenia and compared to matched controls. Overall, Hepatitis C and control patients had similar outcomes. After TKA, fibrotic hepatitis C patients demonstrated a greater average hemoglobin drop than non-fibrotic hepatitis C patients (4.9 versus 3.8, P = 0.023), greater deep infection rate (21% versus 0%, P = 0.047), and rate of cellulitis (21% versus 0%, P = 0.047). Thrombocytopenia showed a trend toward greater infections. Prior to fibrosis, Hepatitis C patients appear to be at no increased risk of complication after joint arthroplasty. Evaluation of fibrosis may predict poor outcome in Hepatitis C patients.  相似文献   
82.
In 2010, the American Society for Bone and Mineral Research (ASBMR) task force defined major and minor features to assist in the case finding and reporting of atypical femoral fractures (AFFs). One major feature that was proposed was a “transverse or short oblique configuration.” Our primary aim was to compare the conventional overall fracture morphology (OFM) with its associated angle (OFMA) and our proposed lateral cortical fracture angle (LCFA) in the assessment of fracture configuration in suspected AFFs and non‐AFFs. The radiographs of 79 patients with AFFs and 39 patients with non‐AFFs were each analyzed by two blinded reviewers to obtain the OFM, OFMA, and LCFA. Using the overall fracture morphology to assess the suspected AFFs resulted in discordance between reviewers in 18 cases (22.8%), of which 5 (6.3%) were discordant between short oblique (>30° to 60°) and long oblique (>60° to 90°) configurations, therefore affecting their classifications as AFFs. By assessing only the critical component within the lateral cortex, all the suspected AFFs fell well within the classification as transverse fractures with a mean LCFA of 4.8° (range 0.3 to 18.0, SD = 4.23). The inter‐reader variability was also lower for LCFA versus OFMA (4.1° versus 6.9°, p = 0.001) when used to assess AFFs. Fracture angles were significantly different in AFFs versus non‐AFFs regardless of whether the OFMA or LCFA methodology was employed, but the greater difference associated with LCFA suggests its greater discriminating power. When LCFA was used in conjunction with 0° to 30° as the criteria for transverse morphology, all the AFFs and non‐AFFs were correctly classified. By using a standardized and precise method in measuring the fracture angle, specifically using only the component of the lateral cortex and limiting to truly transverse fractures, ie, between 0° and 30°, the LCFA is a robust and accurate method to assess the fracture morphology in suspected AFFs. © 2014 American Society for Bone and Mineral Research.  相似文献   
83.
84.
Molecular microbial ecology studies have revealed remarkable prokaryotic diversity in extreme hydrothermal marine environments. There are no comparable reports of culture-independent surveys of eukaryotic life in warm, anoxic marine sediments. By using sequence comparisons of PCR-amplified small subunit ribosomal RNAs, we characterized eukaryotic diversity in hydrothermal vent environments of Guaymas Basin in the Gulf of California. Many sequences from these anoxic sediments and the overlaying seawater represent previously uncharacterized protists, including early branching eukaryotic lineages or extended diversity within described taxa. At least two mechanisms, with overlapping consequences, account for the eukaryotic community structure of this environment. The adaptation to anoxic environments is evidenced by specific affinity of environmental sequences to aerotolerant anaerobic species in molecular trees. This pattern is superimposed against a background of widely distributed aerophilic and aerotolerant protists, some of which may migrate into and survive in the sediment whereas others (e.g., phototrophs) are simply deposited by sedimentary processes. In contrast, bacterial populations in these sediments are primarily characteristic of anoxic, reduced, hydrocarbon-rich sedimentary habitats.  相似文献   
85.
86.
87.
In this practitioner protocol, the radiochemical synthesis of [11C] PABA is described in detail, and a quality control summary of three validation productions is presented. The results indicate that the radiotracer product can be produced in good radiochemical yield (14% at end‐of‐synthesis (EOS)) at high specific activity (molar activity 11 Ci/μmole EOS; 407 GBq/μmole) and high chemical and radiochemical purity as a sterile, pyrogen‐free solution suitable for injection conforming to current Good Manufacturing Practice (cGMP) requirements.  相似文献   
88.
Purpose

The objective of this work was to evaluate the potential of polymeric spherical and aspherical invasive nanocarriers, loaded with antibiotic, to access and treat intracellular bacterial infections.

Methods

Aspherical nanocarriers were prepared by stretching of spherical precursors, and both aspherical and spherical nanocarriers were surface-functionalized with the invasive protein InvA497. The relative uptake of nanocarriers into HEp-2 epithelial cells was then assessed. Nanocarriers were subsequently loaded with a preparation of the non-permeable antibiotic gentamicin, and tested for their ability to treat HEp-2 cells infected with the enteroinvasive bacterium Shigella flexneri.

Results

InvA497-functionalized nanocarriers of both spherical and aspherical shape showed a significantly improved rate and extent of uptake into HEp-2 cells in comparison to non-functionalized nanocarriers. Functionalized and antibiotic-loaded nanocarriers demonstrated a dose dependent killing of intracellular S. flexneri. A slight but significant enhancement of intracellular bacterial killing was also observed with aspherical as compared to spherical functionalized nanocarriers at the highest tested concentration.

Conclusions

InvA497-functionalized, polymer-based nanocarriers were able to efficiently deliver a non-permeable antibiotic across host cell membranes to affect killing of intracellular bacteria. Functionalized nanocarriers with an aspherical shape showed an interesting future potential for intracellular infection therapy.

  相似文献   
89.
Journal of Thrombosis and Thrombolysis - Oral anticoagulants (OACs) are high alert medications and require high-quality management to optimize health outcomes. The objective of this scoping review...  相似文献   
90.
The United States Medical Licensing Examination (USMLE®) Steps are a series of mandatory licensing assessments for all allopathic (MD degree) medical students in their transition from student to intern to resident physician. Steps 1, 2 Clinical Knowledge (CK), and 3 are daylong multiple-choice exams that quantify a medical student’s basic science and clinical knowledge as well as their application of that knowledge using a three-digit score. In doing so, these Steps provide a standardized assessment that residency programs use to differentiate applicants and evaluate their competitiveness. Step 2 Clinical Skills (CS), the only other Step exam and the second component of Step 2, was created in 2004 to test clinical reasoning and patient-centered skills. As a Pass/Fail exam without a numerical scoring component, Step 2 CS provides minimal differentiation among applicants for residency programs. In this personal view article, it is argued that the current Step 2 CS exam should be eliminated for US medical students and propose an alternative consistent with the mission and purpose of the exam that imposes less of a burden on medical students.  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