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   3110篇
  免费   249篇
  国内免费   41篇
耳鼻咽喉   48篇
儿科学   74篇
妇产科学   139篇
基础医学   527篇
口腔科学   45篇
临床医学   387篇
内科学   650篇
皮肤病学   111篇
神经病学   249篇
特种医学   96篇
外科学   277篇
综合类   68篇
预防医学   158篇
眼科学   78篇
药学   243篇
中国医学   15篇
肿瘤学   235篇
  2023年   19篇
  2022年   33篇
  2021年   91篇
  2020年   57篇
  2019年   82篇
  2018年   93篇
  2017年   88篇
  2016年   79篇
  2015年   118篇
  2014年   144篇
  2013年   186篇
  2012年   238篇
  2011年   254篇
  2010年   170篇
  2009年   143篇
  2008年   217篇
  2007年   205篇
  2006年   172篇
  2005年   155篇
  2004年   130篇
  2003年   112篇
  2002年   95篇
  2001年   76篇
  2000年   41篇
  1999年   68篇
  1998年   33篇
  1997年   25篇
  1996年   22篇
  1995年   8篇
  1994年   16篇
  1993年   13篇
  1992年   13篇
  1991年   23篇
  1990年   20篇
  1989年   16篇
  1988年   28篇
  1987年   16篇
  1986年   16篇
  1985年   11篇
  1984年   16篇
  1983年   4篇
  1981年   6篇
  1980年   5篇
  1979年   8篇
  1978年   5篇
  1977年   4篇
  1975年   3篇
  1974年   5篇
  1971年   4篇
  1969年   2篇
排序方式: 共有3400条查询结果,搜索用时 15 毫秒
51.
52.
Chronic lymphocytic leukemia is one of the most common leukemias in the western world and consists of many chromosome aberrations. We report the case of a 74-year-old male patient with chronic lymphocytic leukemia with complex variant translocations t(8;22)(q24;q11) and der(8)t(6;8)(p21;p21) identified by chromosome banding analysis and confirmed by fluorescence in situ hybridization analysis of interphase cells. Because of the rarity of these changes, possible molecular mechanisms associated with this karyotype are discussed.  相似文献   
53.
OBJECTIVES: There is growing evidence suggesting the mutual link between type 2 diabetes mellitus (T2DM) and hepatitis C virus (HCV) infection. However, the impact of HCV infection on the suite of glucose abnormalities has rarely been investigated. The study aimed to determine the difference regarding the prevalence and the characteristics of glucose abnormalities between chronic hepatitis C (CHC) patients and community-based controls. It also aimed to investigate the related clinical, virological, and histological features of glucose abnormalities in HCV infection.
METHODS: Six hundred eighty-three CHC patients and 515 sex-/age-matched controls were included. Oral glucose tolerance test (OGTT) was performed in 522 CHC patients and 447 controls without known T2DM. Clinical data were assessed upon the different stages of glucose abnormalities based on OGTT results.
RESULTS: The prevalence of normoglycemia, IGT, and T2DM in 683 CHC patients was 27.7%, 34.6%, and 37.8%, respectively. There was a significant linear trend from normoglycemia to T2DM in terms of age, family history of T2DM, and advanced liver fibrosis in CHC patients. For those CHC patients without fibrosis, the prevalence of glucose abnormalities reached 67.9% high. All CHC patients carried a significantly higher prevalence than controls regarding those aged <65 yr. For those without known DM, there was a 3.5-fold increase in the prevalence of glucose abnormalities in CHC (65.8%) patients in comparison with controls (35.3%) (OR 3.51, 95% CI 2.70–4.56, P < 0.001).
CONCLUSIONS: CHC patients carried a high prevalence of glucose abnormalities. Determination of glucose abnormalities by OGTT may be suggested.  相似文献   
54.
Leonard  JP; Quinto  CM; Kozitza  MK; Neben  TY; Goldman  SJ 《Blood》1994,83(6):1499-1506
Interleukin-11 (IL-11) is a novel multifunctional hematopoietic cytokine capable of stimulating cells of the myeloid, lymphoid, erythroid, and megakaryocytic lineages in vitro. We have tested the pleiotropic properties of this cytokine on the hematopoietic recovery of mice after a combined regimen of sublethal irradiation and carboplatin administration. This regimen results in severe myelosuppression, characterized by a prolonged period of thrombocytopenia and severe anemia. Administration of recombinant human IL-11 (rhIL-11; 250 micrograms/kg/d) had multilineage effects on bone marrow and spleen hematopoietic activity, increasing the number of megakaryocyte, erythroid, granulocyte, and macrophage progenitors compared with the vehicle-treated controls. This was reflected in the peripheral circulation by a reduction of both the platelet and hematocrit nadirs and a significantly reduced period of thrombocytopenia and anemia in the rhIL-11-treated mice. The results from this study support the broad spectrum of biologic activities that have been attributed to rhIL-11 in vitro and suggest that this cytokine may be an effective agent in the treatment of myelosuppression associated with cancer chemotherapy and bone marrow transplantation.  相似文献   
55.
56.
57.

Objective

To compare the efficacy of intra-articular (IA) steroid injection and distension in patients with frozen shoulder.

Data Sources

Databases, including MEDLINE (via PubMed), Embase, Scopus, and Cochrane Library, were searched for studies published up to November 2016.

Study Selection

We included all published randomized controlled trials (RCTs), quasi-experimental studies, and observational studies investigating the effectiveness of IA steroid injection, distension, and physiotherapy in patients with frozen shoulder. Sixteen RCTs and 1 observational study were enrolled in meta-analysis.

Data Extraction

Full texts were independently reviewed, and quality of RCTs was assessed with The Cochrane Collaboration's tool. The primary outcome was functional improvement; the secondary outcomes included pain reduction and external rotation (ER) improvement.

Data Synthesis

In pairwise meta-analysis, pooled standardized mean difference (SMD) of functional improvement and pain reduction revealed equal efficacy at 3 follow-up time points. With respect to ER improvement, distension has a superior effect compared with IA steroid injection in the short term [(2–4wk; SMD, ?.36; 95% confidence interval [CI], ?.68 to ?.04) and medium term (6–16wk; SMD, ?0.80; 95% CI, ?1.32 to ?0.29). The network meta-analysis indicated a better efficacy for distension than for IA steroid injection in ER improvement only in the medium term (6–16wk; SMD, ?0.70; 95% CI, ?1.19 to ?0.21).

Conclusions

IA steroid injection was as effective as distension in shoulder function improvement, pain reduction, and increasing ER of the shoulder. Distension yielded better ER improvement in the medium term but to a minor extent in the long term. For patients with predominant ER limitation, early distension could be considered the primary choice of treatment.  相似文献   
58.

Objective

To investigate the kinematic and myographic effects of weighted wrist cuffs on individuals with Parkinson disease (PD) during a reaching task.

Design

Cross-sectional study.

Setting

Biomechanics research laboratory.

Participants

Individuals (N=39) with PD (n=19) and healthy age-matched control subjects (n=20).

Interventions

Participants were instructed to reach and grasp a can at a distance of 80% of their arm length without a wrist cuff, while wearing separate 0.5- and 1.0-kg wrist cuffs, and subsequently without a wrist cuff.

Main Outcome Measures

Movement time, kinematic, and electromyographic data were recorded during all reach and grasp movements. Four end point coordinate strategy variables, 3 joint recruitment variables, and 2 co-contraction indices were derived from the raw data for analysis.

Results

Significant interaction effects were found in the trunk and index finger movement time as the weight of the cuff increased from 0.5 to 1.0kg. The group of individuals with PD showed decreased movement times in both instances, whereas the control group showed increased movement times as the weight of the wrist cuff increased from baseline to 0.5 and 1.0kg. No group difference was observed in the co-contraction index of the upper arm and forearm.

Conclusions

Adoption of weighted wrist cuffs in the clinic should be cautiously undertaken because compensatory movements may be induced in the trunk of individuals with PD.  相似文献   
59.

Background and Purpose

μ-Opioid receptors, pro-opiomelanocortin and pro-enkephalin are highly expressed in the nucleus tractus solitarii (NTS) and μ receptor agonists given to the NTS dose-dependently increased BP. However, the molecular mechanisms of this process remain unclear. In vitro, μ receptors heterodimerize with α2A-adrenoceptors. We hypothesized that α2A-adrenoceptor agonists would lose their depressor effects when their receptors heterodimerize in the NTS with μ receptors.

Experimental Approach

We microinjected μ-opioid agonists and antagonists into the NTS of rats and measured changes in BP. Formation of μ receptor/α2A-adrenoceptor heterodimers was assessed with immunofluorescence and co-immunoprecipitation methods, along with proximity ligation assays.

Key Results

Immunofluorescence staining revealed colocalization of α2A-adrenoceptors and μ receptors in NTS neurons. Co-immunoprecipitation revealed interactions between α2A-adrenoceptors and μ receptors. In situ proximity ligation assays confirmed the presence of μ receptor/α2A-adrenoceptor heterodimers in the NTS. Higher levels of endogenous endomorphin-1 and μ receptor/α2A-adrenoceptor heterodimers were found in the NTS of hypertensive rats, than in normotensive rats. Microinjection of the μ receptor agonist [D-Ala2, MePhe4, Gly5-ol]-enkephalin (DAMGO), but not that of the α2A-adrenoceptor agonist guanfacine, into the NTS of normotensive rats increased μ receptor/α2A-adrenoceptor heterodimer formation and BP elevation. The NO-dependent BP-lowering effect of α2A-adrenoceptor agonists was blunted following increased formation of μ receptor/α2A-adrenoceptor heterodimers in the NTS of hypertensive rats and DAMGO-treated normotensive rats.

Conclusions and Implications

Increases in endogenous μ receptor agonists in the NTS induced μ receptor/α2A-adrenoceptor heterodimer formation and reduced the NO-dependent depressor effect of α2A-adrenoceptor agonists. This process could contribute to the pathogenesis of hypertension.  相似文献   
60.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathic disease in Taiwan. The mass neonatal screening of G6PD deficiency by fluorometric spot test in Taiwan was started with a pilot program in 1984. The nationwide screening was started on July 1, 1987, and a follow-up system comprising of eighteen referral hospitals, including outlying islands, was organized for confirmatory test, medical care and genetic counseling. From July 1987 to December 1997, 2,971,192 heel blood samples collected on filter paper from 1,143 delivery units were screened by four neonatal screening centers. 46,570 cases were confirmed as G6PD deficiency is estimated to be around 2.1% (male 3.1%, female 0.9%) in Taiwan. The coverage rate of neonatal screening was 99% in 1997. To assess the reliability of the confirmatory test, an external quality assurance (QA) program for G6PD assay was developed. Periodically, 3 or 5 lyophilized quality control materials with different activities of G6PD were sent to each referral hospital by speed post delivery in dry ice. From January 1988 to June 1998, 85 QA services were performed. Two hundred and seven (13.5%) abnormal QA results were found, which were attributed to clerk (11.6%), procedural (16.4%), and instrumental errors (47.3%). In aid to confirm G6PD deficiency, a method to detect the G6PD mutation by using the dried blood samples was developed. The frequencies of the mutant alleles in Taiwan were determined to be 46.8% (1376G > T), 16.2% (1388G > A), 7.9% (95A > G), 6.5% (493A > G), 5.6% (392G >T), 4.6% (1024C > T), 0.5% (487G > A) and 0.5% (519C > G), respectively.  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