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   2205681篇
  免费   170081篇
  国内免费   7327篇
耳鼻咽喉   29648篇
儿科学   71020篇
妇产科学   59965篇
基础医学   306297篇
口腔科学   61954篇
临床医学   198312篇
内科学   437281篇
皮肤病学   52113篇
神经病学   175851篇
特种医学   90295篇
外国民族医学   472篇
外科学   342454篇
综合类   49277篇
现状与发展   3篇
一般理论   656篇
预防医学   167554篇
眼科学   48534篇
药学   164540篇
  10篇
中国医学   4397篇
肿瘤学   122456篇
  2018年   22458篇
  2017年   17766篇
  2016年   20929篇
  2015年   23313篇
  2014年   32224篇
  2013年   47881篇
  2012年   61164篇
  2011年   65319篇
  2010年   39921篇
  2009年   38468篇
  2008年   60992篇
  2007年   65126篇
  2006年   66555篇
  2005年   63807篇
  2004年   61069篇
  2003年   59198篇
  2002年   56725篇
  2001年   112198篇
  2000年   115458篇
  1999年   96102篇
  1998年   25596篇
  1997年   22570篇
  1996年   23312篇
  1995年   24144篇
  1994年   22355篇
  1993年   21015篇
  1992年   77088篇
  1991年   74813篇
  1990年   72600篇
  1989年   69689篇
  1988年   63854篇
  1987年   62575篇
  1986年   58997篇
  1985年   56395篇
  1984年   42017篇
  1983年   35311篇
  1982年   20999篇
  1981年   18578篇
  1980年   17559篇
  1979年   37750篇
  1978年   26525篇
  1977年   22923篇
  1976年   20594篇
  1975年   22263篇
  1974年   26060篇
  1973年   25059篇
  1972年   23476篇
  1971年   21816篇
  1970年   19972篇
  1969年   18968篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
1.
Modified-release opioids are often prescribed for the management of moderate to severe acute pain following total hip and knee arthroplasty, despite recommendations against their use due to increasing concerns regarding harm. The primary objective of this multicentre study was to examine the impact of modified-release opioid use on the incidence of opioid-related adverse events compared with immediate-release opioid use, among adult inpatients following total hip or knee arthroplasty. Data for total hip and knee arthroplasty inpatients receiving an opioid analgesic for postoperative analgesia during hospitalisation were collected from electronic medical records of three tertiary metropolitan hospitals in Australia. The primary outcome was the incidence of opioid-related adverse events during hospital admission. Patients who received modified with or without immediate-release opioids were matched to those receiving immediate-release opioids only (1:1) using nearest neighbour propensity score matching with patient and clinical characteristics as covariates. This included total opioid dose received. In the matched cohorts, patients given modified-release opioids (n = 347) experienced a higher incidence of opioid-related adverse events overall, compared with those given immediate-release opioids only (20.5%, 71/347 vs. 12.7%, 44/347; difference in proportions 7.8% [95%CI 2.3–13.3%]). Modified-release opioid use was associated with an increased risk of harm when used for acute pain during hospitalisation after total hip or knee arthroplasty.  相似文献   
2.
3.
Colorectal cancer (CRC) is the third most diagnosed cancer and the second leading cause of cancer-related mortality in the United States. Across the globe, people in the age group older than 50 are at a higher risk of CRC. Genetic and environmental risk factors play a significant role in the development of CRC. If detected early, CRC is preventable and treatable. Currently, available screening methods and therapies for CRC treatment reduce the incidence rate among the population, but the micrometastasis of cancer may lead to recurrence. Therefore, the challenge is to develop an alternative therapy to overcome this complication. Nanotechnology plays a vital role in cancer treatment and offers targeted chemotherapies directly and selectively to cancer cells, with enhanced therapeutic efficacy. Additionally, nanotechnology elevates the chances of patient survival in comparison to traditional chemotherapies. The potential of nanoparticles includes that they may be used simultaneously for diagnosis and treatment. These exciting properties of nanoparticles have enticed researchers worldwide to unveil their use in early CRC detection and as effective treatment. This review discusses contemporary methods of CRC screening and therapies for CRC treatment, while the primary focus is on the theranostic approach of nanotechnology in CRC treatment and its prospects. In addition, this review aims to provide knowledge on the advancement of nanotechnology in CRC and as a starting point for researchers to think about new therapeutic approaches using nanotechnology.  相似文献   
4.
Objective: Cancer is a huge problem of disease globally. Today, the percentage of people die from cancer is more than a combination of various diseases. In females, most common types of malignancies that occur are breast and cervical. The present focus has been shifted on medicinal plants as a form of therapy and there is a constant need to identify new therapeutic agents. Choerospondias axillaris (C. axillaris), an underutilized fruit, has been used in the remedy of various diseases. In the present communication, we evaluated the molecular mechanism of C. axillaris methanol extract in regulating cell death in human breast cancer cells (MDA-MB-231). Methods: Methanol extract of C. axillaris was prepared and compounds were screened by Gas chromatography-mass spectrometry. The effect of fruit extract was determined on MDA-MB-231 cells by MTT ((3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay and to analyse the molecular mechanism of human breast cancer cells after treating with fruit extract, protein profiling study was performed by two-dimensional gel electrophoresis. Results: A total 9 differentially expressed proteins were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS/MS) analysis. Among 9 identified proteins, synphilin-1 protein was found to be significantly downregulated, validated by western blot and RT-qPCR analysis. Possible interacting partners of synphilin-1 (SNCAIP) were analyzed for their possible role in cancer by the in-silico method. Conclusion: Our data implicate that the presence of bioactive compound(s) in C. axillaris fruits might play an important role in inhibiting the proliferation of breast carcinoma cells and Synphilin-1 protein may play a role of apoptotic function.  相似文献   
5.
6.
Microbial co-infections are another primary concern in patients with coronavirus disease 2019 (COVID-19), yet it is an untouched area among researchers. Preliminary data and systematic reviews only show the type of pathogens responsible for that, but its pathophysiology is still unknown. Studies show that these microbial co-infections are hospital-acquired/nosocomial infections, and patients admitted to intensive care units with invasive mechanical ventilation are highly susceptible to it. Patients with COVID-19 had elevated inflammatory cytokines and a weakened cell-mediated immune response, with lower CD4+ T and CD8+ T cell counts, indicating vulnerability to various co-infections. Despite this, there are only a few studies that recommend the management of co-infections.  相似文献   
7.
8.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Heavy metal concentrations in surface soils of Reserved Forests (RFs) have a significant impact on...  相似文献   
9.
10.
Clinical Rheumatology - Aimed to evaluate the time elapsed between the onset of early symptoms and the diagnosis of fibromyalgia syndrome (FMS), the delays in diagnosis and frequent physician...  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