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   1945篇
  免费   155篇
  国内免费   41篇
耳鼻咽喉   20篇
儿科学   43篇
妇产科学   39篇
基础医学   342篇
口腔科学   19篇
临床医学   229篇
内科学   450篇
皮肤病学   22篇
神经病学   171篇
特种医学   111篇
外科学   162篇
综合类   20篇
预防医学   184篇
眼科学   9篇
药学   212篇
中国医学   1篇
肿瘤学   107篇
  2023年   10篇
  2022年   16篇
  2021年   24篇
  2020年   30篇
  2019年   24篇
  2018年   48篇
  2017年   31篇
  2016年   31篇
  2015年   35篇
  2014年   60篇
  2013年   98篇
  2012年   107篇
  2011年   125篇
  2010年   69篇
  2009年   66篇
  2008年   91篇
  2007年   122篇
  2006年   89篇
  2005年   95篇
  2004年   86篇
  2003年   81篇
  2002年   94篇
  2001年   57篇
  2000年   62篇
  1999年   66篇
  1998年   31篇
  1997年   45篇
  1996年   43篇
  1995年   29篇
  1994年   25篇
  1993年   18篇
  1992年   39篇
  1991年   41篇
  1990年   24篇
  1989年   32篇
  1988年   22篇
  1987年   18篇
  1986年   20篇
  1985年   14篇
  1984年   20篇
  1983年   13篇
  1982年   11篇
  1981年   9篇
  1980年   9篇
  1979年   8篇
  1978年   7篇
  1976年   8篇
  1972年   5篇
  1970年   4篇
  1967年   4篇
排序方式: 共有2141条查询结果,搜索用时 15 毫秒
1.
2.
OBJECTIVE: According to a report published by the federation of Dutch patients' associations, patients would like to see a pharmacist, who acts more as a personal adviser. This raised the question, how often Dutch community pharmacists have personal consultations with their patients in daily practice, on which factors this depends, and what kind of topics are discussed during these meetings. SETTING: Community pharmacies in the Netherlands. METHOD: A questionnaire was distributed among 800 randomly selected pharmacies. Questions were restricted to consultations characterized by one-to-one contact, drug therapy related content, and adequate privacy. These consultations were labelled as pharmaceutical consultations in private to distinguish them from other contacts between pharmacists and patients. MAIN OUTCOME MEASURE: Number, content, and character of consultations. RESULTS: 198 (24.8%) community pharmacies responded. The pharmacists provide an average of roughly 1.2 consultations in private per working day. The vast majority of respondents provided face-to-face and telephone consultations (94.4 and 91.9%, respectively), only a minority gave consultations by e-mail (30.8%). These consultations primarily dealt with topics related to medication safety. The mean overall time spent was 290 min per month. A relatively high frequency of personal consultations was significantly associated with the absolute number of full-time equivalent pharmacists in the pharmacy. CONCLUSION: The frequency of pharmaceutical consultations in private is low, but may be improved by reorganisation of the pharmacist's activities. The possibility of personal consultations by e-mail is not yet well-developed. Further research is needed to assess the patient's view of pharmaceutical consultations in private.  相似文献   
3.
The activities of hexokinase, phosphofructokinase, aldolase, enolase and pyruvate kinase were studied in breast cancer tissues, in comparison to benign breast disease and normal breast tissues. The enzyme activities in breast cancer were significantly increased compared to normal and benign breast tissues (p less than 0.001). Also the increase in activity in benign disease compared to normal was statistically significant (p less than 0.001). Within the group of benign diseases, fibroadenomas could be distinguished from fibrocystic disease, the former generally showing higher activities compared to the latter (p less than or equal to 0.05). Carcinoma subgroups, classified according to their histology, could not be recognized enzymologically. In addition, isozyme composition of pyruvate kinase and enolase was studied. We did not find a significant shift towards K type pyruvate kinase expression in benign disease compared to normal breast tissues. Also fibroadenomas did not differ from fibrocystic disease. However, the amount of K type pyruvate kinase in carcinomas proved to be significantly higher in comparison to benign disease and normal breast tissues (p less than 0.001). Expression of alpha gamma-enolase in normal breast tissue was virtually absent. In benign disease only a minority of specimens did show the hybrid alpha gamma-enolase. Nearly all carcinomas had alpha gamma-enolase expression and in 20% of the carcinomas gamma gamma-enolase could be detected (so-called neuron-specific enolase). By discriminant analysis, the function giving the best discrimination compared to the histological data was based on natural logarithm aldolase and the total of gamma-enolase subunits. Contrary to expectation, the regulator enzymes of glycolysis; i.e., hexokinase, phosphofructokinase and pyruvate kinase were not included in this discriminant function. The best fit produced a 90% correct classification in both benign and malignant disease. If these findings are confirmed to a larger series, the discrimination is sufficiently strong to form the basis of a clinically useful tool.  相似文献   
4.
Background: Recent development of extracorporeal magnetic stimulation (ECMS) which uses current‐changing magnetic fields allows the induction of electrical stimulation in the desired deep tissue. Recent study showed the sacral nerve stimulation reduces corticoanal excitability that may play a functional role in anal continence mechanisms. Preliminary study shows that ECMS of sacral nerve can modify pelvic floor function and expel rectal balloon in patients with pelvic floor dyssynergia (PFD). Aims: To evaluate the effect of ECMS compared with biofeedback therapy (BF) in patients with PFD. Methods and Materials: Thirty‐eight patients who fulfilled Rome II criteria for PFD by colon transit time and anorectal function tests, were randomly treated with 8 sessions of ECMS (2/weeks; n = 19) at prone position or BF (2/weeks; n = 19) at sitting position. Stimulation parameters were set at 50–80% of maximum intensity, 10 and 50 Hz frequency, 3 s burst length with 3 and 6 s off using arm‐typed stimulator (BioCom‐1000, Mcube Co., Korea). Symptom scores for constipation with/without anorectal function test were repeatedly measured after each treatment. Response was defined as 50% or more decreased symptom score after treatment (partial response: 30–50%, poor: <30%). Results: Fifteen patients (age 49.1 ± 13.4 years, mean ± SD; 4 men) completed 8 session of BF and 14 patients (54.5 ± 17.6 years, 3 men) completed 8 session of ECMS. Four patients of BF group discontinued treatment due to unsatisfactory therapeutic effect (n = 1) and withdrew consent (n = 3) and 5 patients of ECMS group discontinued treatment because of same reasons (n = 1, 4). Total symptom scores were significantly decreased after treatment of 8 session in both treatment groups (13.4 ± 6.6 vs. 4.3 ± 4.0 for BF, p = 0.009; 14.9 ± 5.6 vs. 3.4 ± 4.0 for ECMS, p < 0.001). Bowel movements per week were also significantly increased after treatment in both groups (median 2 vs. 7 for BF, p = 0.035; median 2 vs. 7 for ECMS, p = 0.008). Thirteen out of 15 patients showed response in BF group and 12 out of 14 showed good response in ECMS group. No adverse effects in both groups. Conclusions: ECMS is as effective as BF for the treatment of PFD. Long‐term effect of ECMS for the patients with pelvic floor dyssynergia need to be evaluated in the near future.  相似文献   
5.
OBJECTIVE: This study was designed to evaluate the efficacy of magnesium carbonate as a phosphate binder in hemodialysis patients. DESIGN: This study was a prospective, randomized, open-label trial comparing magnesium carbonate/calcium carbonate versus calcium acetate as a sole phosphate binder. SETTING: This study involved outpatient hemodialysis. PARTICIPANTS: We recruited 30 stable hemodialysis patients without a history of frequent diarrhea. INTERVENTION: After receiving informed consent, we randomized patients 2:1 to magnesium carbonate versus calcium acetate. The dose of each binder was titrated to achieve the Kidney Disease Outcomes Quality Initiative (K/DOQI) phosphate target of <5.5 mg/dL. MAIN OUTCOME MEASURE: The efficacy-phase serum phosphorus concentration and the percentage of patients meeting K-DOQI targets for phosphorus, along with the daily elemental calcium intake, were the primary outcome measures. RESULTS: Magnesium carbonate provided equal control of serum phosphorus (70.6% of the magnebind group and 62.5% of the calcium acetate group had their average serum phosphorus within the K-DOQI target during the efficacy phase), while significantly reducing daily elemental calcium ingestion from phosphate binders (908 +/- 24 vs. 1743 +/- 37 mg/day, P < .0001). CONCLUSION: Magnesium carbonate was generally well-tolerated in this selected patient population, and was effective in controlling serum phosphorus while reducing elemental calcium ingestion.  相似文献   
6.
In a previous study in conscious spontaneously hypertensive rats (SHR), we observed an immediate decrease in the cardiac index (CI) and an increase in the total peripheral resistance index (TPRI) following the administration of furosemide. The present study was designed to evaluate the regional hemodynamic effects and the involvement of sinoaortic baroreceptors in the increase in TPRI. In SHR instrumented for the measurement of central hemodynamics, 8 mg.kg-1 furosemide decreased CI from 31.0 +/- 2.5 ml.min-1.100 g bw-1 by 9.5 +/- 1.3 ml.min-1.100 g bw-1 (n = 7). TPRI increased maximally from 5.7 +/- 0.8 by 2.7 +/- 0.5 mm Hg.min.100 g bw.ml-1. The effect on TPRI was not affected by sinoaortic denervation (SAD) to abolish arterial baroreflexes. However, furosemide induced a significantly greater decrease in CI (-12.6 +/- 1.2 ml.min-1.100 g bw-1; n = 7) after SAD. Furosemide effectively reduced the mean arterial pressure in SAD SHR (-21 +/- 9 mm Hg) but not in sham-denervated SHR. Furosemide (8 mg.kg-1) reduced renal, mesenteric and hindquarter blood flow to a comparable extent (approximately 20%) in intact SHR. The reduction in renal flow at 3.5 min after injection (-17.9 +/- 4.1%; n = 8) was significantly greater than the reduction in mesenteric (-7.1 +/- 4.7%) and hindquarter blood flow (-4.2 +/- 3.7%), suggesting that the renal bed responds faster. Thereafter, the flow reductions in the three beds were not different. The results show that furosemide causes a general vasoconstriction in conscious SHR.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
7.
8.
Infection with human immunodeficiency virus (HIV) and the resulting immunosuppression are associated with an increased risk for human papillomavirus (HPV) persistence and related malignancies. In the present study we investigated the prevalence of HPV in urine samples from 104 HIV-infected men with low CD4+ cell counts (<100 per mm(3)) and 115 urine samples from HIV-negative men. A high prevalence of HPV DNA (39.4%) was found in the HIV patients. Most of the HPV types were high risk (81.4%), with HPV 52 as the most prevalent type (12.5%), followed by HPV 18 (6.7%), HPV 35 (5.8%), and HPV 70 (4.8%). Multiple HPV genotypes were observed in 17 (41%) of the 41 HPV- and HIV-positive men. In contrast, only 11 (9.6%) HPV DNA-positive cases were observed among the 115 HIV-uninfected men, and 3 (27.3%) contained multiple genotypes. Quantitative analyses indicated that the HPV viral load, as measured in urine samples, is significantly higher in HIV-positive men compared to HIV-negative men. In the present study we show that urine samples are useful for detecting HPV DNA, there is a high prevalence of HPV in HIV-positive men, and the HPV viral load is substantially higher in HIV-positive than in HIV-negative men. More studies are needed to evaluate the risk and natural development of HPV-related malignancies in HIV-positive men.  相似文献   
9.
Cells with an endothelial phenotype can be cultured from peripheral blood. These cells include cells of a monocytic origin with endothelial features (culture-modified mononuclear cells, CMMCs) and, at later time points, blood outgrowth endothelial cells (BOECs). Both are promising candidates for systemic cell-based cardiovascular therapies and each may have unique capabilities. Indeed, the combined use of both cell types has been shown to have synergistic therapeutic features requiring simultaneous delivery. However, the majority of preclinical studies of cell delivery have used splenectomized animals to increase systemic distribution. The goal of this study was to directly compare the distribution of these two cell types following systemic delivery in an intact animal model. A similar pattern of delivery was seen following delivery of both cell types with detection in the lung, liver, bone marrow, and spleen. Taken together, the data suggest that strategies using systemic delivery of circulation-derived cells must consider the distribution and efficiency of delivery in intact animals.  相似文献   
10.
The expression of adhesion receptors and diapedesis by polymorphonuclear neutrophils (PMN) were studied before and during experimentally induced Streptococcus uberis mastitis. Both quarters of the left half of the udders of five midlactation cows were inoculated with a suspension containing approximately 500 CFU of S. uberis 0140J. Clinical signs of an inflammatory reaction and leukocyte influx were observed 24 h after challenge. The expression of CD11b/CD18 adhesion receptors, determined by flow cytometry, was upregulated 24 h after challenge. A confluent monolayer of bovine secretory mammary epithelial cells on collagen-coated inserts was used to study PMN diapedesis. Bovine C5a was used as the chemoattractant. An 80% decrease in PMN diapedesis was observed 24 h after challenge. The decrease in diapedesis continued for 3 weeks after challenge.  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