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   416篇
  免费   31篇
  国内免费   6篇
儿科学   8篇
妇产科学   10篇
基础医学   58篇
口腔科学   2篇
临床医学   28篇
内科学   100篇
皮肤病学   28篇
神经病学   28篇
特种医学   7篇
外科学   33篇
综合类   3篇
预防医学   58篇
眼科学   1篇
药学   25篇
中国医学   1篇
肿瘤学   63篇
  2023年   3篇
  2022年   8篇
  2021年   9篇
  2020年   9篇
  2019年   10篇
  2018年   15篇
  2017年   7篇
  2016年   9篇
  2015年   13篇
  2014年   18篇
  2013年   21篇
  2012年   39篇
  2011年   23篇
  2010年   28篇
  2009年   14篇
  2008年   31篇
  2007年   16篇
  2006年   11篇
  2005年   19篇
  2004年   12篇
  2003年   19篇
  2002年   20篇
  2001年   1篇
  2000年   4篇
  1999年   6篇
  1998年   10篇
  1997年   10篇
  1996年   7篇
  1995年   7篇
  1994年   6篇
  1993年   3篇
  1992年   5篇
  1991年   5篇
  1990年   3篇
  1988年   3篇
  1987年   2篇
  1986年   4篇
  1985年   6篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   7篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1957年   1篇
排序方式: 共有453条查询结果,搜索用时 531 毫秒
131.
This study evaluated changes in lymphocyte subsets in patients with thyroid carcinoma who received iodine-131 for diagnostic and therapeutic purposes. Twenty thyroid cancer patients were entered in the study after total thyroidectomy: ten patients (group A) underwent whole-body scintigraphy with 185 MBq of 131I and the other ten (group B) received 3700 MBq of 131I therapy. All patients were in a hypothyroid state at the time of administration of 131I and started l-thyroxine 150 μg/day 3 days after 131I administration. Free and bound triiodothyronine and thyroxine, thyroid-stimulating hormone, thyroglobulin, thyroglobulin antibodies, thyroid peroxidase/microsomal antibodies, white blood cell, lymphocyte counts and lymphocyte subsets were serially determined at baseline and at days 2, 7, 15, 30 and 60 after 131I administration. Twenty healthy age- and sex-matched individuals were used as a reference population for lymphocyte subset values. In group A only a reduction in NK cells at days 7 (P=0.043) and 15 (P=0.037) was observed. In group B, patients showed a delayed reduction in the total lymphocyte count at days 15, 30 and 60 (P=0.008, 0.004 and 0.018, respectively), and a decrease in B cells throughout the study (at days 7, 15, 30 and 60: P=0.006, 0.0017, 0.0017 and 0.0017 respectively). A transient decrease in NK cells was observed at days 15 (P=0.025) and 30 (P=0.008). Among T cells, the helper phenotype (CD4+) was mainly affected, resulting in a reduction in the CD4+/CD8+ ratio at day 60 (P=0.046). Comparing the two groups, the numbers of B lymphocytes at day 30 (P=0.023) and NK cells at days 2 (P=0.037) and 30 (P=0.023) were significantly lower in group B. Neither group showed any clinical sign of immunosuppression during the follow-up period. In patients with thyroid cancer the sensitivity of lymphocytes to the effects of 131I administered for diagnostic or therapeutic purposes depends upon lymphocyte phenotype and 131I activity. NK cells are the most radiosensitive cells, being reduced even by low 131I activity. At higher activity all subtypes show a reduction, which is more marked and prolonged for B lymphocytes and, to a lesser extent, for T-helper lymphocytes. These changes do not result in clinically relevant immunosuppression. Received 6 March and in revised form 29 April 1999  相似文献   
132.
We applied double gradient-denaturing gradient gel electrophoresis (DG-DGGE) for the rapid detection of rifampin (RMP) resistance from rpoB PCR products of Mycobacterium tuberculosis isolates and clinical samples. The results of this method were fully concordant with those of DNA sequencing and susceptibility testing analyses. DG-DGGE is a valid alternative to the other methods of detecting mutations for predicting RMP resistance.  相似文献   
133.
134.

Background

Polysensitization, defined as being allergic to three or more haptens from the European baseline series, is considered to reflect increased susceptibility to developing a contact allergy, and is likely to be associated with an impaired quality of life.

Objectives

To evaluate the prevalences of polysensitization across Europe and to analyse factors associated with polysensitization.

Methods

Patch test data collected by the European Surveillance System on Contact Allergies (ESSCA; www.essca‐dc.org ) in consecutively patch tested patients from January 2009 to December 2014, comprising 11 countries and 57 departments, were retrospectively analysed.

Results

A total of 86 416 patients were available for analysis, showing a standardized prevalence of polysensitization of 7.02%, ranging from 12.7% (Austria) to 4.6% (Italy). Allergen pairs with the strongest association are reported for the total population, for South Europe, and for North/Central Europe. Overall, polysensitized patients showed a higher percentage of extreme (+++) positive patch test reactions than oligosensitized patients. Female sex, occupational dermatitis and age > 40 years were risk factors for polysensitization.

Conclusions

The varying prevalences of polysensitization across Europe most likely reflect differences in patient characteristics and referral patterns between departments. Known risk factors for polysensitization are confirmed in a European dermatitis population.
  相似文献   
135.
ObjectiveThe aim of this study was to describe sugary drink (beverages with free sugars), sugar-sweetened beverage (beverages with added sugars, SSB) and 100% juice (beverages with natural sugars) consumption across socioeconomic position (SEP) among Canadians.MethodsWe conducted a cross-sectional analysis of 19,742 respondents of single-day 24-h dietary recalls in the nationally representative 2015 Canadian Community Health Survey–Nutrition. Poisson regressions were used to estimate the prevalence of consuming each beverage type on a given day. Among consumers on a given day, linear regressions were used to estimate mean energy intake. Models included household education, food security and income quintiles as separate unadjusted exposures. Sex-specific models were estimated separately for children/adolescents (2–18 years) and adults (19 +).ResultsAmong female children/adolescents, the prevalence of consuming sugary drinks and, separately, SSB ranged from 11 to 21 and 8 to 27 percentage-points higher among lower education compared to ‘Bachelor degree or above’ households. In female adults, the prevalence of consuming sugary drinks and, separately, SSB was 10 (95% CI: 1, 19) and 14 (95% CI: 2, 27) percentage-points higher in food insecure compared to secure households. In males, the prevalence of consuming 100% juice was 9 (95% CI: − 18, 0) percentage-points lower among food insecure compared to secure households. Social inequities in energy intake were observed in female adult consumers, among whom mean energy from sugary drinks was 27 kcal (95% CI: 3, 51) higher among food insecure compared to secure and 35 kcal (95% CI: 2, 67) higher from 100% juice among ‘less than high school’ education compared to ‘Bachelor degree or above’ households.ConclusionSocial inequities in sugary drink consumption exist in Canada. The associations differed by SEP indicator. Equitable interventions to reduce consumption are warranted.  相似文献   
136.
Testicular cancer health education: an integrative review   总被引:1,自引:0,他引:1  
Cancer of the testis is the most common malignancy in men between the ages of 15 and 35, yet it is one of the most curable cancers The optimistic prognosis that results from early detection and treatment of testicular cancer underscores the critical need for teaching testicular self-examination (TSE) However, anintegrative review of the health education literature suggests that the men most susceptible are virtually unaware of the symptoms of testicular cancer and how to detect them Although educational materials have been available, very little intervention research has been published on testicular cancer The literature to date has focused on the psychosocial factors associated with the practice of TSE and increasing knowledge of testicular cancer Although an important beginning step, knowledge of testicular cancer alone as a preventive health behaviour is not sufficient if young men either do not know how to do the examination on their own testicles or do not believe it is important to them Nurses should incorporate health education for testicular cancer and TSE in the delivery of routine primary health care Furthermore, future research should aim to (a) increase knowledge through the educational curricula of high schools and colleges by use of video presentations, (b) examine the efficacy of using silicone models to ensure that men can be trained to detect the symptoms of testicular cancer, and (c) study compliance with recommendations to perform TSE  相似文献   
137.
OBJECTIVE: To evaluate the efficacy of two doses of recombinant (r)LH, 75 IU (recommended) or 37.5 IU, for follicular stimulation and outcomes in a randomized cohort of IVF patients. DESIGN: Randomized, prospective analysis. SETTING: Private hospital incorporating an established IVF center. PATIENT(S): Women undergoing IVF who had a body mass index >18 or <35 and no abnormal karyotype, anovulation, oligomenorrhea, or any known endocrinopathy/illness. INTERVENTION(S): Pituitary desensitization was achieved with triptorelin (0.1 mg SC), and gonadotropin stimulation was performed with either rFSH alone (group A) or in combination with rLH in one of two doses: 37.5 IU (group B) or 75 IU (group C), daily. MAIN OUTCOME MEASURE(S): A range of endocrinologic, embryologic, clinical, and outcome parameters were evaluated. RESULT(S): With rLH supplementation there was a significant increase in the incidence of implantation (9% for rFSH only [group A] vs. 11% and 16% with 37.5 IU rLH and 75.0 IU rLH [groups B and C], respectively) and clinical pregnancy (19% vs. 23% and 31%) (P<.01 and P<.04, respectively), whereas there was no difference in the multiple pregnancy rates. There was a significant (P<.001) increase in the total units of rFSH used in proportion to the amount of rLH supplementation (2,645 U vs. 3,475 U and 3,681 U) and in the level of peripheral E(2) on the day of hCG administration (1,049 pg/mL vs. 1,640 pg/mL and 1,226 pg/mL) (P<.001). There was no significant between difference in mean age, numbers of oocytes recovered, basal and downregulation hormone levels, or the incidence of fertilization in the absence or presence of rLH supplementation, but a higher incidence of grade 1 to 2 embryos was observed when rLH was supplemented. CONCLUSION(S): After pituitary desensitization, there was an increase in the incidence of implantation, clinical pregnancy, and delivery rates in patients stimulated with rFSH supplemented with rLH.  相似文献   
138.
INTRODUCTION: Albumin excretion rate is usually increased in people who smoke, but the physiological basis of this phenomenon is not fully understood. METHODS: The effect of chronic smoking on renal haemodynamics was studied in a cohort of 66 men. Twenty-seven were smokers and 36 were hypertensive. In all subjects, the albumin excretion rate was evaluated; in hypertensive patients, a renoscintigraphic evaluation of renal plasma flow and glomerular filtration were carried out and the filtration fraction was calculated. RESULTS: The hypertensive smoking population presented an increased urinary albumin excretion rate in comparison with hypertensive non-smoking patients. No significant differences were found for the mean values of renal plasma flow, the glomerular filtration rate and the filtration fraction between hypertensive smokers and hypertensive non-smoking patients. CONCLUSIONS: In hypertensive patients, smoking does not modify typical renal haemodynamic changes of arterial hypertension; however, it significantly increases the albumin excretion rate.  相似文献   
139.
OBJECTIVES: To identify independent risk factors of symptomatic deep vein thrombosis (DVT) in geriatric inpatients and to define high-risk patients likely to benefit from preventive treatment. DESIGN: Hospital-based case-control multicenter study with prospective data collection. SETTINGS: Geriatric university hospitals with long-, intermediate-, and short-term care facilities. PARTICIPANTS: All patients aged 65 and older in 19 geriatric departments were submitted to clinical surveillance over a 16-month period. MEASUREMENTS: Twenty-three potential risk factors of phlebitis were screened for. Comparison using logistic regression of 310 consecutive patients with symptomatic DVT versus 310 randomly selected controls was performed. The risk for symptomatic DVT in geriatrics was then scored from the clinical risk factors identified using multivariate analysis. This score is defined by the sum of the odds ratio (OR) of each risk factor present. RESULTS: Six factors were identified as independently related to the development of DVT: restriction of mobility (from OR=1.73, limited mobility without immobilization, to OR=5.64, bedridden during <15 days), aged 75 and older (OR=1.5/10 years), history of DVT or pulmonary embolism (OR=3.38), acute heart failure (OR=2.52), chronic edema of the lower limbs (OR=2.51), and paresis or paralysis of a lower limb (OR=2.06). The defined score of 8 or higher corresponded to an 88.7% probability of having symptomatic DVT. CONCLUSION: Treatments to prevent symptomatic DVT in hospitalized elderly should be evaluated on patients with these factors.  相似文献   
140.
The design, synthesis, and biological properties of novel inhibitors of the Na(+),K(+)-ATPase as potential positive inotropic compounds are reported. Following our model of superposition between cassaine and digitoxigenin, digitalis-like activity has been elicited from a non-digitalis steroidal structure by suitable modifications of the 5alpha,14alpha-androstane skeleton. The strong hydrophobic interaction of the digitalis or cassaine polycyclic cores can be effectively obtained with the androstane skeleton taken in a reversed orientation. Thus, oxidation of C-6 and introduction in the C-3 position of the potent pharmacophoric group recently introduced by us, in the 17 position of the digitalis skeleton, namely, O-(omega-aminoalkyl)oxime, led to a series of substituted androstanes able to inhibit the Na(+),K(+)-ATPase, most of them with an IC(50) in the low micromolar level, and to induce a positive inotropic effect in guinea pig. Within this series, androstane-3,6,17-trione (E,Z)-3-(2-aminoethyl)oxime (22b, PST 2744) induced a strong positive inotropic effect while being less arrhythmogenic than digoxin, when the two compounds were compared at equiinotropic doses.  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