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   1663篇
  免费   161篇
  国内免费   3篇
耳鼻咽喉   14篇
儿科学   56篇
妇产科学   30篇
基础医学   252篇
口腔科学   18篇
临床医学   168篇
内科学   302篇
皮肤病学   48篇
神经病学   125篇
特种医学   40篇
外科学   156篇
综合类   19篇
一般理论   3篇
预防医学   225篇
眼科学   33篇
药学   152篇
中国医学   2篇
肿瘤学   184篇
  2023年   19篇
  2022年   25篇
  2021年   49篇
  2020年   45篇
  2019年   39篇
  2018年   63篇
  2017年   68篇
  2016年   55篇
  2015年   51篇
  2014年   63篇
  2013年   103篇
  2012年   143篇
  2011年   134篇
  2010年   55篇
  2009年   57篇
  2008年   95篇
  2007年   89篇
  2006年   67篇
  2005年   54篇
  2004年   45篇
  2003年   56篇
  2002年   53篇
  2001年   21篇
  2000年   23篇
  1999年   17篇
  1998年   10篇
  1997年   6篇
  1994年   8篇
  1992年   15篇
  1991年   21篇
  1990年   12篇
  1989年   9篇
  1988年   16篇
  1987年   19篇
  1986年   11篇
  1985年   17篇
  1984年   7篇
  1983年   8篇
  1980年   9篇
  1978年   11篇
  1977年   9篇
  1975年   11篇
  1974年   5篇
  1973年   6篇
  1972年   7篇
  1971年   5篇
  1970年   8篇
  1967年   7篇
  1926年   5篇
  1919年   7篇
排序方式: 共有1827条查询结果,搜索用时 31 毫秒
1.

Introduction The focus in clinical pharmacy practice is and has for the last 30–35 years been on changing the role of pharmacy staff into service orientation and patient counselling. One way of doing this is by involving staff in change process and as a researcher to take part in the change process by establishing partnerships with staff. On the background of the authors’ widespread action research (AR)-based experiences, recommendations and comments for how to conduct an AR-study is described, and one of their AR-based studies illustrate the methodology and the research methods used. Methodology AR is defined as an approach to research which is based on a problem-solving relationship between researchers and clients, which aims at both solving a problem and at collaboratively generating new knowledge. Research questions relevant in AR-studies are: what was the working process in this change oriented study? What learning and/or changes took place? What challenges/pitfalls had to be overcome? What were the influence/consequences for the involved parts? When to use If you want to implement new services and want to involve staff and others in the process, an AR methodology is very suitable. The basic advantages of doing AR-based studies are grounded in their participatory and democratic basis and their starting point in problems experienced in practice. Limitations Some of the limitations in AR-studies are that neither of the participants in a project steering group are the only ones to decide. Furthermore, the collective process makes the decision-making procedures relatively complex.

  相似文献   
2.
3.
Background: Anesthesia is associated with complications, and some of them may be fatal. The authors investigated the circumstances under which deaths were associated with anesthesia. In Denmark, the specialty anesthesiology encompasses emergency medicine, chronic and acute pain medicine, anesthetic procedures, perioperative care medicine, and intensive care medicine.

Methods: The authors retrospectively investigated anesthesia related deaths registered by the Danish Patient Insurance Association.

Results: From 1996 to 2004, 27,971 claims were made by the Danish Patient Insurance Association covering all medical specialties, of which 1,256 files (4.5%) were related to anesthesia. In 24 cases, the patient's death was considered to result from the anesthetic procedure: 4 deaths were related to airway management, 2 to ventilation management, 4 to central venous catheter placement, 4 as a result of medication errors, 4 from infusion pump problems, and 4 after complications from regional blockades. Severe hemorrhage caused 1 death, and in 1 case the cause was uncertain.  相似文献   

4.
The association between serum selenium concentration and a number of coronary heart disease risk factors is studied in 364 males from southern Italy participating in the Olivetti Heart Study. Selenium correlates positively and significantly with serum cholesterol (r = 0.120; P = 0.022), and this positive association persists after adjustment for age and body mass index. Selenium levels in heavy smokers are lower than both light smokers and current non-smokers, but these differences do not reach statistical significance. Selenium is not significantly associated with any of the other CHD risk factors (e.g., triglycerides, HDL cholesterol, blood pressure, age, and body mass index). It is hypothesized that the association between selenium and serum cholesterol reported in this and previous studies could be due to dietary interrelationships between selenium intake and foods that affect serum cholesterol concentrations.  相似文献   
5.
In 295 patients with transitional cell tumours of the upper urinary tract no significant relationship was found comparing blood groups A and O and the rhesus system to histological grade and invasive or non-invasive growth.  相似文献   
6.
Pseudomonas aeruginosa causes a chronic infection in the lungs of cystic fibrosis (CF) patients by establishing an alginate-containing biofilm. The infection has been studied in several animal models; however, most of the models required artificial embedding of the bacteria. We present here a new pulmonary mouse model without artificial embedding. The model is based on a stable mucoid CF sputum isolate (NH57388A) with hyperproduction of alginate due to a deletion in mucA and functional N-acylhomoserine lactone (AHL)-based quorum-sensing systems. Chronic lung infection could be established in both CF mice (Cftr(tmlUnc-/-)) and BALB/c mice, as reflected by the detection of a high number of P. aeruginosa organisms in the lung homogenates at 7 days postinfection and alginate biofilms, surrounded by polymorphonuclear leukocytes in the alveoli. In comparison, both an AHL-producing nonmucoid revertant (NH57388C) from the mucoid isolate (NH57388A) and a nonmucoid isolate (NH57388B) deficient in AHL were almost cleared from the lungs of the mice. This model, in which P. aeruginosa is protected against the defense system of the lung by alginate, is similar to the clinical situation. Therefore, the mouse model provides an improved method for evaluating the interaction between mucoid P. aeruginosa, the host, and antibacterial therapy.  相似文献   
7.
Sera from 159 men attending the sexually transmitted disease clinic at Karolinska Hospital, Stockholm, Sweden, were analyzed for the presence of immunoglobulin A (IgA) and IgG antibodies to a panel of synthetic peptides derived from the E2, L1, and L2 regions of the human papillomavirus types 1 (HPV 1), 6, 8, 11, 16, 18, 31, and 33. The study subjects were divided into three groups: (i) asymptomatic men with no history of genital warts who served as controls, (ii) men with visible condylomata, and (iii) men who had previously been afflicted with condylomata. There were no significant differences in antibody titers for any of the HPV 6- or 11-derived peptides among patients with current condylomata and the controls. For the peptide from L1 of HPV 6, there was an increase in the IgG titers among men with previous condylomata compared with the titers for the controls (52% versus 27% seropositivity; P less than 0.05). Also, for the peptide from L2 of HPV 6, there was an increase in the IgG titers among men who had been afflicted with condylomata previously (P less than 0.05). Increased IgA antibody titers against an HPV 16-derived peptide and an HPV 18-derived peptide were also detected. For the peptides from L1 and L2 of HPV 6, the study was extended to an additional group of 127 males attending the sexually transmitted disease clinic at Huddinge Hospital in southern Stockholm. Again, significantly increased antibody levels were detected only for IgG and only among asymptomatic men with a history of condylomata (P < 0.01 for the L1 peptide and P < 0.05 for the L2 peptide). The results suggest that the IgG response against the late proteins of HPV 6 reflects mainly previous exposure to the virus rather than ongoing viral disease.  相似文献   
8.
Whereas the stress-inducible heat-shock protein 70 (Hsp70) has gained plenty of attention as a putative target for tumor therapy, little is known about the role of other Hsp70 proteins in cancer. Here we present the first thorough analysis of the expression and function of the cytosolic Hsp70 proteins in human cancer cells and identify Hsp70-2, a protein essential for spermatogenesis, as an important regulator of cancer cell growth. Targeted knock-down of the individual family members by RNA interference revealed that both Hsp70 and Hsp70-2 were required for cancer cell growth, whereas the survival of tumorigenic as well as nontumorigenic cells depended on Hsc70. Cancer cells depleted for Hsp70 and Hsp70-2 displayed strikingly different morphologies (detached and round vs. flat senescent-like), cell cycle distributions (G2/M vs. G1 arrest) and gene expression profiles. Only Hsp70-2 depletion induced the expression of macrophage inhibitory cytokine-1 that was identified as a target of P53 tumor-suppressor protein and a mediator of the G1 arrest and the senescent phenotype. Importantly, concomitant depletion of Hsp70 and Hsp70-2 had a synergistic antiproliferative effect on cancer cells. Thus, highly homologous Hsp70 proteins bring about nonoverlapping functions essential for cell growth and survival.  相似文献   
9.

Introduction

MED13L-related intellectual disability is characterized by moderate intellectual disability (ID), speech impairment, and dysmorphic facial features. We present 8 patients with MED13L-related intellectual disability and review the literature for phenotypical and genetic aspects of previously described patients.

Materials and methods

In the search for genetic aberrations in individuals with ID, two of the patients were identified by chromosomal microarray analysis, and five by exome sequencing. One of the individuals, suspected of MED13L-related intellectual disability, based on clinical features, was identified by Sanger sequencing.

Results

All 8 individuals had de novo MED13L aberrations, including two intragenic microdeletions, two frameshift, three nonsense variants, and one missense variant. Phenotypically, they all had intellectual disability, speech and motor delay, and features of the mouth (open mouth appearance, macroglossia, and/or macrostomia). Two individuals were diagnosed with autism, and one had autistic features. One had complex congenital heart defect, and one had persistent foramen ovale. The literature was reviewed with respect to clinical and dysmorphic features, and genetic aberrations.

Conclusions

Even if most clinical features of MED13L-related intellectual disability are rather non-specific, the syndrome may be suspected in some individuals based on the association of developmental delay, speech impairment, bulbous nasal tip, and macroglossia, macrostomia, or open mouth appearance.  相似文献   
10.
In the present study we examined whether exercise and prostanoids have an effect on the muscle interstitial concentration of vascular endothelial growth factor (VEGF) and on the proliferative effect of muscle interstitial fluid. Dialysate from resting and exercising human skeletal muscle, obtained either during control conditions or during cyclooxygenase inhibition, was examined for its content of VEGF and for its effect on endothelial cell proliferation. Microdialysis probes with high (960 kDa) and low (5 kDa) molecular-mass cut-off membranes were placed in the vastus lateralis muscle of healthy young males. The subjects performed one-legged knee extensions (20 W). The concentration of VEGF in the 960 kDa dialysate was greater (   P < 0.05  ) during exercise compared to at rest (67 ± 28 vs. 230 ± 22 pg ml−1). The rate of endothelial cell proliferation was 2.7-fold higher (   P < 0.05  ) with the 960 kDa dialysate from resting muscle than with perfusate and was 5.8-fold higher (   P < 0.05  ) than the perfusate value with dialysate from exercising muscle. VEGF was not enhanced with exercise in the 5 kDa dialysate, yet the exercise dialysate induced a 1.9-fold higher (   P < 0.05  ) proliferation than the resting dialysate. Cyclooxygenase inhibition did not affect the VEGF concentration or the proliferating effect of the dialysates (   P > 0.05  ). This study demonstrates for the first time that VEGF is present in the interstitium of human skeletal muscle and that exercise enhances the interstitial concentration of VEGF and of other, as yet unidentified, angiogenic compounds. Products of cyclooxygenase do not appear to have an effect on the release of VEGF or other proliferative agents in human skeletal muscle.  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