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   506篇
  免费   55篇
  国内免费   11篇
耳鼻咽喉   15篇
儿科学   8篇
妇产科学   3篇
基础医学   58篇
口腔科学   10篇
临床医学   54篇
内科学   155篇
皮肤病学   6篇
神经病学   33篇
特种医学   11篇
外国民族医学   1篇
外科学   61篇
综合类   12篇
预防医学   26篇
眼科学   31篇
药学   39篇
中国医学   5篇
肿瘤学   44篇
  2023年   8篇
  2022年   19篇
  2021年   27篇
  2020年   11篇
  2019年   18篇
  2018年   27篇
  2017年   5篇
  2016年   15篇
  2015年   24篇
  2014年   26篇
  2013年   34篇
  2012年   29篇
  2011年   32篇
  2010年   9篇
  2009年   21篇
  2008年   20篇
  2007年   27篇
  2006年   35篇
  2005年   24篇
  2004年   18篇
  2003年   21篇
  2002年   16篇
  2001年   15篇
  2000年   11篇
  1999年   4篇
  1998年   2篇
  1995年   7篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1989年   6篇
  1988年   3篇
  1987年   9篇
  1986年   5篇
  1985年   5篇
  1984年   1篇
  1983年   3篇
  1982年   4篇
  1981年   2篇
  1980年   3篇
  1979年   3篇
  1978年   3篇
  1977年   1篇
  1973年   3篇
  1971年   1篇
  1970年   1篇
  1968年   1篇
  1936年   1篇
排序方式: 共有572条查询结果,搜索用时 14 毫秒
101.

Objective

This study aimed to describe the positions of the lamina papyracea (LP) in patients who had nasal polypi, by computed tomography (CT) analysis.

Methods

Paranasal CT scans of patients diagnosed to have nasal polypi were included in the study. CT images were acquired with multiplanar reformates to obtain delicate details in coronal planes for all subjects. Positions of the LP were registered then analyzed in relation to nasal polypi grading.

Results

Forty seven subjects (94 nasal sides) were included in the current study. Grade I lamina detected in 50% or more of all cases. Patients who had larger polypi (polyp grade 3, 4) were associated with significantly more medial LP (grade II) than smaller polypi (polyp grade 0, 1, 2) (P = 0.00386).

Conclusion

The current study improves surgeons’ awareness of LP position in different grades of nasal polypi and highlights that larger polypi are significantly associated with more medial LP than smaller polypi. This may be one of the causes of the higher incidence of complication in larger polypi and can help for safer surgery.  相似文献   
102.

Background

Canal wall down (CWD) mastoidectomy has many drawbacks including chronic otorrhea, granulations, dizziness on exposure to cold or hot water and tendency of debris accumulation in the mastoid cavity demanding periodic cleaning. Many of these problems can be solved by reconstruction of the posterior meatal wall (PMW).

Objectives

To assess the results of PMW reconstruction after CWD mastoidectomy for cholesteatoma using bioactive glass (BAG) that is fabricated and built up intraoperatively.

Patients and methods

This study was applied on 20 patients had atticoantral chronic suppurative otitis media. All cases were subjected to CWD mastoid surgery with complete elimination of the disease and reconstruction of the PMW by BAG that was prepared and built up intraoperatively. All patients were exposed to full preoperative evaluation and full postoperative assessment of complications, appearance of the external auditory canal contour, and the hearing gain expressed by the change of the air bone gap postoperatively.

Results

During a follow up of 12 to 36?months, postoperative appearance of external auditory canal contour was found smooth without hidden pouches, irregularities nor stenosis in all cases. No registered granulation, foreign body reaction, nor extrusion and/or displacement of the BAG material. No reported facial palsy or recurrent cholesteatoma. Significant hearing improvement was statistically reported (p?=?0.0006).

Conclusion

Surgical reconstruction of the PMW using BAG that operatively fashioned immediately after CWD mastoidectomy appears to be reliable without considerable complications giving smooth appearance of the PMW and improving the hearing.  相似文献   
103.
We seek to understand what is known about the use of visual art‐making for people who have a cancer diagnosis, and to explore how art‐making may help address fatigue in the cancer care context. Art‐making involves creating art or craft alone or in a group and does not require an art‐therapist as the emphasis is on creativity rather than an overt therapeutic intention. An integrative review was undertaken of qualitative, quantitative and mixed‐method studies on art‐making for people who have cancer, at any stage of treatment or recovery. An adapted version of Kaplan's Attention Restoration Theory (ART) was used to interpret the themes found in the literature. Fifteen studies were reviewed. Nine concerned art‐making programmes and six were focused on individual, non‐facilitated art‐making. Review results suggested that programme‐based art‐making may provide participants with opportunities for learning about self, support, enjoyment and distraction. Individual art‐making can provides learning about self, diversion and pleasure, self‐management of pain, a sense of control, and enhanced social relationships. When viewed through the lens of ART, art‐making can be understood as an energy‐restoring activity that has the potential to enhance the lives of people with a diagnosis of cancer.  相似文献   
104.
Many causes for ABO discrepancy between red blood cell and serum testing have been cited in the literature. ABO discrepancy due to weak or absent reverse type is most often seen at the extremes of age. We report a case of ABO discrepancy in a 25-year-old woman who presented for wisdom teeth extraction. Initial serologic workup revealed total absence of isohemagglutinin anti-B in this group A, D+ individual. Further evaluation revealed decreased levels of all classes of immunoglobulins and a medical history significant for multiple episodes of infection. Based on the patient's history and laboratory data, she was diagnosed with common variable immunodeficiency (CVID). CVID can cause ABO discrepancy in an adult patient because of an absent ABO reverse type.  相似文献   
105.
Although previous studies demonstrated carbonic anhydrase (CA) activity in the human endometrium, the CA isozyme(s) responsible for this activity has not been established. In this report, we provide the first evidence that the CA isozyme XII, a recently identified transmembrane isozyme that is expressed in normal kidney and greatly overexpressed in some renal cancers, is present in endometrium. We show by immunohistochemistry that CA XII is expressed in the basolateral plasma membrane of epithelial cells of normal human endometrium. Expression of CA XII in uterus was confirmed by Northern blotting. Detergent-solubilized CA XII was isolated from human endometrium by inhibitor affinity chromatography and characterized by isoelectric focusing and Western blot as a polypeptide with a pI of 6.3. The high expression of CA XII in the endometrial epithelium suggests that it may be functionally linked to the pH-dependent events in spermatozoa that precede fertilization. Its basolateral location and extracellular active site could also allow it to influence the morphological changes in endometrium that occur during the menstrual cycle.  相似文献   
106.
107.
Background: There is a lack of information on CYP2D6, a major metabolizing enzyme, in Africa ethnic nationalities. The objective was to determine CYP2D6 phenotype in Yoruba Nigerians using dextromethorphan (DEX).

Method: A total of 89 healthy volunteers received 30 mg of DEX orally followed by blood and urine sample collection at 3-hour and over 8 h post-dose, respectively. DEX and dextrorphan (DOR) concentrations were determined using High Performance Liquid Chromatography (HPLC). The metabolic ratio (MR, DEX/DOR) were plotted for the phenotype determination.

Results: The log MR that separated poor (PMs) from normal metabolizers (NMs) was 0.28 and 0.75 for urine and plasma, respectively. Two subjects (2.3%) identified as PMs had a mean MR of 17 and 3.2 in plasma and urine, significantly higher than that of NMs (p < .0001). A positive correlation between urine and plasma MR was noted.

Conclusion: The prevalence of PMs in the Yoruba Nigerians was similar to that reported among blacks.  相似文献   
108.
Pesticides are highly toxic substances. Their toxicity may not be absolutely specific to the target organisms but can adversely affect different processes in the non-target host plants. In the present study, the effect of over application of four commonly used pesticides (emamectin benzoate, alpha-cypermethrin, lambda-cyhalothrin and imidacloprid) was evaluated on the germination, seedling vigor and photosynthetic pigments in tomato. The obtained results revealed that seed germination was decreased by the pesticides and this effect was more prominent at early stages of exposure. All the tested pesticides reduced the growth of tomato when applied in higher concentration than the recommended dose, but at lower doses the pesticides had some stimulatory effects on growth as compared to the control. A similar effect of pesticides was observed on the photosynthetic pigments, i.e. a decrease in pigments concentrations was caused at higher doses but an increase was observed at lower doses of pesticides. The calculation of EC50 values for different parameters revealed the lowest EC50 values for emamectin (ranged as 51–181 mg/L) followed by alpha-cypermethrin (191.74–374.39), lambda-cyhalothrin (102.43–354.28) and imidacloprid (430.29–1979.66 mg/L). A comparison of the obtained EC50 values for different parameters of tomato with the recommended doses revealed that over application of these pesticides can be harmful to tomato crop. In a few cases these pesticides were found toxic even at the recommended doses. However, a field based study in this regard should be conducted to further verify these results.  相似文献   
109.
110.
IntroductionType II diabetes mellitus (DM) is a proinflammatory process and a known risk factor for major adverse cardiac events (MACE). The same inflammatory markers may be present in prediabetes (pDM); however, the relationship between pDM by HbA1c and MACE is not well studied. We sought to see if pDM increases one’s risk for MACE.MethodsWe retrospectively studied patients at Beaumont Health, Michigan between 2006 and 2020. We divided patients into groups (G1–G5) based on haemoglobin A1c (HbA1c) trends over the study period as follows: G1: pDM patients who remained pDM; G2: pDM who progressed into DM; G3: pDM who normalized their HbA1c; G4: patients who maintained a normal HbA1c; and G5: patients with HbA1c persistently in the DM range. We compared MACE between the groups by univariate and multivariate regression analyses.ResultsA total of 119,271 patients were included in the study (G1: N = 13,520, G2: N = 6314, G3: N = 1585, G4: N = 15,018, G5: N = 82,834). Pairwise comparison revealed a statistically significant increase in the odds of MACE in all groups compared to those with normal HbA1c values (G4; p < .001). After adjusting for baseline characteristics, multivariate regression revealed elevated odds of MACE in patients with persistent pDM (G1; aOR = 1.087, p = .002) and diabetes (G2/G5; aOR = 1.25 and aOR = 1.18, p < .001) compared to individuals with normal HbA1c values.ConclusionPrediabetes is a risk factor for MACE. Normalization of HbA1c values appears to decrease the adjusted risk for MACE and should be the goal in patients with pDM.

KEY MESSAGES

  • Patients with prediabetes (pDM) are at increased risk for major cardiovascular events.
  • Normalization of HbA1c in pDM patients may have a clinically significant benefit, in terms of lowering the MACE risk.
  • Prediabetes patients who progress into diabetes mellitus may represent a particularly high-risk group.
  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