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   2000篇
  免费   110篇
  国内免费   76篇
耳鼻咽喉   1篇
儿科学   171篇
妇产科学   26篇
基础医学   221篇
口腔科学   58篇
临床医学   252篇
内科学   500篇
皮肤病学   73篇
神经病学   60篇
特种医学   391篇
外科学   89篇
综合类   44篇
预防医学   87篇
眼科学   19篇
药学   84篇
  2篇
肿瘤学   108篇
  2023年   5篇
  2022年   7篇
  2021年   11篇
  2020年   14篇
  2019年   15篇
  2018年   32篇
  2017年   22篇
  2016年   22篇
  2015年   39篇
  2014年   48篇
  2013年   57篇
  2012年   34篇
  2011年   37篇
  2010年   88篇
  2009年   84篇
  2008年   51篇
  2007年   91篇
  2006年   51篇
  2005年   53篇
  2004年   24篇
  2003年   17篇
  2002年   27篇
  2001年   36篇
  2000年   29篇
  1999年   29篇
  1998年   128篇
  1997年   159篇
  1996年   131篇
  1995年   108篇
  1994年   114篇
  1993年   97篇
  1992年   28篇
  1991年   35篇
  1990年   36篇
  1989年   54篇
  1988年   46篇
  1987年   42篇
  1986年   49篇
  1985年   45篇
  1984年   26篇
  1983年   15篇
  1982年   24篇
  1981年   29篇
  1980年   25篇
  1979年   4篇
  1978年   8篇
  1977年   18篇
  1976年   25篇
  1975年   14篇
  1966年   1篇
排序方式: 共有2186条查询结果,搜索用时 20 毫秒
971.
We aimed to explore the real experience of patients after liver transplantation in the intensive care unit (ICU).Objective sampling method was used to select patients transferred to the ICU in 10 hospitals in Zhuhai from May 2018 to August 2020. Patients need liver transplantation due to advanced liver cancer and decompensated cirrhosis. The eligibility criteria of patients mainly included liver transplant patients who were clear-minded and willing to participate in the study and had stayed in ICU. Phenomenological research methods and in-depth interviews were used in this qualitative study.The results showed that the true experience of patients after liver transplantation during ICU stay was summarized into four themes. The strengths of our qualitative research are that we can find the trend from a phenomenon through interviews and other methods to provide a directional foundation for future quantitative research. Its limitations are that it requires a lot of manpower and time, and its objectivity and universality are limited.Hospitalization experience in the ICU may lead to many negative experiences for liver transplant patients. Nurses should fully understand and pay attention to the psychological changes in patients. Nurses should take effective targeted measures to reduce or eliminate patients’ fear of ICU stay and promote rehabilitation.  相似文献   
972.

Background

Depression is a common complication in type 2 diabetes (DM2), affecting 10-30% of patients. Since depression is underrecognized and undertreated, it is important that reliable and validated depression screening tools are available for use in patients with DM2. The Edinburgh Depression Scale (EDS) is a widely used method for screening depression. However, there is still debate about the dimensionality of the test. Furthermore, the EDS was originally developed to screen for depression in postpartum women. Empirical evidence that the EDS has comparable measurement properties in both males and females suffering from diabetes is lacking however.

Methods

In a large sample (N = 1,656) of diabetes patients, we examined: (1) dimensionality; (2) gender-related item bias; and (3) the screening properties of the EDS using factor analysis and item response theory.

Results

We found evidence that the ten EDS items constitute a scale that is essentially one dimensional and has adequate measurement properties. Three items showed differential item functioning (DIF), two of them showed substantial DIF. However, at the scale level, DIF had no practical impact. Anhedonia (the inability to be able to laugh or enjoy) and sleeping problems were the most informative indicators for being able to differentiate between the diagnostic groups of mild and severe depression.

Conclusions

The EDS constitutes a sound scale for measuring an attribute of general depression. Persons can be reliably measured using the sum score. Screening rules for mild and severe depression are applicable to both males and females.  相似文献   
973.
同型半胱氨酸(Hcy)是蛋氨酸代谢中间产物,是一种含硫基的氨基酸。1964年Gibson等首先报道高同型半胱氨酸血症与血管性疾病和血栓形成相关,1969年Mcully提出Hcy可能与动脉粥样硬化有关。随着近30年的深入研究,众多资料表明高Hcy血症(hHcy)是心脑血管病变的一个独立危险因素。  相似文献   
974.

INTRODUCTION

Introducing laparoscopic colorectal surgery is a challenge to the whole surgical team. It is usual for an assistant to hold the laparoscope and be responsible for the surgeon''s view of the operative field and a lack of expertise in the assistant can add significant difficulties. The EndoAssist™ is a robotic device that replaces the human assistant and ensures steady visualisation of the operative field and a view which can be controlled by the surgeon. This study describes its use in the introduction of laparoscopic colorectal surgery to a unit.

PATIENTS AND METHODS

The EndoAssist was employed for the introduction of laparoscopic colorectal surgery in a unit with previous experience of this device for laparoscopic cholecystectomy. It was used in a consecutive series of 77 laparoscopic colectomy operations.

RESULTS

The robotic device proved successful in the whole range of colorectal operations and a reliable assistant. No problems specific to the device were encountered.

CONCLUSIONS

The EndoAssist robot is a useful laparoscopic assistant and aided in the introduction of laparoscopic colorectal surgery.  相似文献   
975.
976.

Objectives

Efavirenz‐based HIV therapy is associated with breast hypertrophy and gynaecomastia. Here, we tested the hypothesis that efavirenz induces gynaecomastia through direct binding and modulation of the oestrogen receptor (ER).

Methods

To determine the effect of efavirenz on growth, the oestrogen‐dependent, ER‐positive breast cancer cell lines MCF‐7, T47D and ZR‐75‐1 were treated with efavirenz under oestrogen‐free conditions in the presence or absence of the anti‐oestrogen ICI 182,780. Cells treated with 17β‐oestradiol in the absence or presence of ICI 182,780 served as positive and negative controls, respectively. Cellular growth was assayed using the crystal violet staining method and an in vitro receptor binding assay was used to measure the ER binding affinity of efavirenz.

Results

Efavirenz induced growth in MCF‐7 cells with an estimated effective concentration for half‐maximal growth (EC50) of 15.7 μM. This growth was reversed by ICI 182,780. Further, efavirenz binds directly to the ER [inhibitory concentration for half maximal binding (IC50) of ~52 μM] at a roughly 1000‐fold higher concentration than observed with 17β‐oestradiol.

Conclusions

Our data suggest that efavirenz‐induced gynaecomastia may be caused, at least in part, by drug‐induced ER activation in breast tissues.  相似文献   
977.
978.

Background

In rehabilitation, training intensity is usually adapted to optimize the trained system to attain better performance (overload principle). However, in balance rehabilitation, the level of intensity required during training exercises to optimize improvement in balance has rarely been studied, probably due to the difficulty in quantifying the stability level during these exercises. The goal of the present study was to test whether the stabilizing/destabilizing forces model could be used to analyze how stability is challenged during several exergames, that are more and more used in balance rehabilitation, and a dynamic functional task, such as gait.

Methods

Seven healthy older adults were evaluated with three-dimensional motion analysis during gait at natural and fast speed, and during three balance exergames (50/50 Challenge, Ski Slalom and Soccer). Mean and extreme values for stabilizing force, destabilizing force and the ratio of the two forces (stability index) were computed from kinematic and kinetic data to determine the mean and least level of dynamic, postural and overall balance stability, respectively.

Results

Mean postural stability was lower (lower mean destabilizing force) during the 50/50 Challenge game than during all the other tasks, but peak postural instability moments were less challenging during this game than during any of the other tasks, as shown by the minimum destabilizing force values. Dynamic stability was progressively more challenged (higher mean and maximum stabilizing force) from the 50/50 Challenge to the Soccer and Slalom games, to the natural gait speed task and to the fast gait speed task, increasing the overall stability difficulty (mean and minimum stability index) in the same manner.

Conclusions

The stabilizing/destabilizing forces model can be used to rate the level of balance requirements during different tasks such as gait or exergames. The results of our study showed that postural stability did not differ much between the evaluated tasks (except for the 50/50 Challenge), compared to dynamic stability, which was significantly less challenged during the games than during the functional tasks. Games with greater centre of mass displacements and changes in the base of support are likely to stimulate balance control enough to see improvements in balance during dynamic functional tasks, and could be tested in pathological populations with the approach used here.  相似文献   
979.
Cytokines are major immune system regulators. Previously, innate cytokine profiles determined by lipopolysaccharide stimulation were shown to be highly heritable. To identify regulating genes in innate immunity, we analyzed data from a genome-wide linkage scan using microsatellites in osteoarthritis (OA) patients (The GARP study) and their innate cytokine data on interleukin (IL)-1β, IL-1Ra, IL-10 and tumor necrosis factor (TNF)α. A confirmation cohort consisted of the Leiden 85-Plus study. In this study, a linkage analysis was followed by manual selection of candidate genes in linkage regions showing LOD scores over 2.5. An single-nucleotide polymorphism (SNP) gene tagging method was applied to select SNPs on the basis of the highest level of gene tagging and possible functional effects. QTDT was used to identify the SNPs associated with innate cytokine production. Initial association signals were modeled by a linear mixed model. Through these analyses, we identified 10 putative genes involved in the regulation of TNFα. SNP rs6679497 in gene CD53 showed significant association with TNFα levels (P=0.001). No association of this SNP was observed with OA. A novel gene involved in the innate immune response of TNFα is identified. Genetic variation in this gene may have a role in diseases and disorders in which TNFα is closely involved.  相似文献   
980.
Acute hyperglycaemia has been associated with complications, prolonged intensive care unit and hospital stay, and increased mortality. We made an inventory of the prevalence and prognostic value of hyperglycaemia, and of the effects of glucose control in different groups of critically ill patients. The prevalence of hyperglycaemia in critically ill patients, using stringent criteria, approaches 100%. An unambiguous negative correlation between hyperglycaemia and mortality has been described in various groups of critically ill patients. Although the available evidence remains inconsistent, there appears to be a favourable effect of glucose regulation. This effect on morbidity and mortality depends on patient characteristics. To be able to compare results of future studies involving glucose regulation, better definitions of hyperglycaemia (and consequently of normoglycaemia) and patient populations are needed.  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