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   898篇
  免费   34篇
  国内免费   14篇
耳鼻咽喉   23篇
儿科学   26篇
妇产科学   8篇
基础医学   82篇
口腔科学   19篇
临床医学   47篇
内科学   110篇
皮肤病学   61篇
神经病学   200篇
特种医学   80篇
外科学   62篇
综合类   9篇
预防医学   41篇
眼科学   2篇
药学   96篇
中国医学   1篇
肿瘤学   79篇
  2021年   10篇
  2020年   6篇
  2019年   4篇
  2018年   9篇
  2017年   10篇
  2016年   16篇
  2015年   13篇
  2014年   14篇
  2013年   18篇
  2012年   35篇
  2011年   35篇
  2010年   36篇
  2009年   40篇
  2008年   39篇
  2007年   48篇
  2006年   41篇
  2005年   44篇
  2004年   42篇
  2003年   28篇
  2002年   43篇
  2001年   28篇
  2000年   24篇
  1999年   32篇
  1998年   22篇
  1997年   16篇
  1996年   14篇
  1995年   13篇
  1994年   18篇
  1993年   18篇
  1992年   17篇
  1991年   19篇
  1990年   23篇
  1989年   27篇
  1988年   25篇
  1987年   15篇
  1986年   12篇
  1985年   8篇
  1984年   8篇
  1983年   13篇
  1982年   4篇
  1981年   7篇
  1980年   5篇
  1979年   7篇
  1978年   8篇
  1977年   6篇
  1976年   7篇
  1968年   6篇
  1967年   2篇
  1966年   2篇
  1965年   3篇
排序方式: 共有946条查询结果,搜索用时 15 毫秒
1.
The present article reports the preparation, characterization and performance evaluation of solid lipid nanoparticles (SLNs) based on polyoxyethylene-40 stearate (PEG-40 stearate) for the administration of antifungal agents such as ketoconazole and clotrimazole. These nanoparticles could be useful in the treatment of vaginal infections sustained by Candida albicans. In particular, PEG-40 stearate was made to react with acryloyl chloride in order to introduce an easily polymerizable moiety for the creation of a second shell and to ensure a slow drug release. In addition, the differences on the release profiles between PEG-40 stearate-based nanoparticles, PEG-40 stearate acrylate based and polymerized ones, were analyzed under conditions, simulating the typical environment of Candida albicans infection. Then, the antifungal activity of nanoparticles was also evaluated in terms of minimal inhibitory concentration. Moreover, the nanoparticles were submitted to in vitro studies for evaluating the drug permeability at the site of action. Results indicated that the obtained particles are potentially useful for the treatment of vaginal infections sustained by Candida albicans.  相似文献   
2.
3.
Inflammatory bowel disease (IBD) could be associated with several extra-intestinal manifestations (EIMs) involving musculoskeletal, hepatopancreatobiliary, ocular, renal, and pulmonary systems, as well as the skin. In the last years, hidradenitis suppurativa (HS) is acquiring an increasing interest. IBD, especially Crohn’s disease (CD), is among the most reported associated diseases in HS patients. The aim of this paper is to give a brief overview of data showing a possible epidemiologic and pathogenetic association between IBD and HS. We performed a pooled-data analysis of four studies and pooled prevalence of HS in IBD patients was 12.8%, with a 95%CI of 11.7%-13.9%. HS was present in 17.3% of subjects with CD (95%CI: 15.5%-19.1%) and in 8.5% of UC patients (95%CI: 7.0%-9.9%). Some items, especially altered immune imbalance, are generally involved in IBD pathogenesis as well as invoked by HS. Smoking is one of the most relevant risk factors for both disorders, representing a predictor of their severity, despite, actually, there being a lack of studies analyzing a possible shared pathway. A role for inheritance in HS and CD pathogenesis has been supposed. Despite a genetic susceptibility having been demonstrated for both diseases, further studies are needed to investigate a genetic mutual route. Although the pathogenesis of IBD and HS is generally linked to alterations of the immune response, recent findings suggest a role for intestinal and skin microbiota, respectively. In detail, the frequent finding of Staphylococcus aureus and coagulase-negative staphylococci on HS cutaneous lesions suggests a bacterial involvement in disease pathogenesis. Moreover, microflora varies in the different cutaneous regions of the body and, consequently, two different profiles of HS patients have been identified on these bases. On the other hand, it is well-known that intestinal microbiota may be considered as “the explosive mixture” at the origin of IBD despite the exact relationship having not been completely clarified yet. A better comprehension of the role that some bacterial species play in the IBD pathogenesis may be essential to develop appropriate management strategies in the near future. A final point is represented by some similarities in the therapeutic management of HS and IBD, since they may be controlled by immunomodulatory drugs. In conclusion, an unregulated inflammation may cause the lesions typical of both HS and IBD, particularly when they coexist. However, this is still a largely unexplored field.  相似文献   
4.
A study regarding patients with primary and previously untreated advanced histologically proven squamous cell carcinoma of the head and neck was performed to compare two treatment modalities: neck dissection followed by chemoradiotherapy (Group I) versus chemoradiotherapy alone (Group II). Fifty-four patients were randomly chosen to receive Group I or II treatment. Our results demonstrate that Group I treatment has a higher and statistically significant disease-specific survival rate. We suggest that an association of neck dissection plus chemoradiotherapy can be useful in the event of unresectable advanced carcinomas.  相似文献   
5.
OBJECTIVE: The rationale for using tazarotene in oral lichen planus (OLP) is its regulatory action on the growth and differentiation of keratinocytes and on inflammation. This randomized, placebo-controlled study addresses evaluation of the effects of topic tazarotene in the treatment of OLP. DESIGN: The degree of lesions before and after treatment scored by a 6-score scale in six cases treated with tazarotene was statistically compared with those of six controls treated with placebo. SUBJECTS: Twelve patients with hyperkeratosic OLP were randomly allocated to treatment with tazarotene gel 0.1% b.i.d. or with placebo for eight consecutive weeks. METHODS: The statistical comparison was executed by means of Wilcoxon analysis for paired data. RESULTS: Patients treated with tazarotene presented a significant reduction of their lesions as compared with the control group. Among transitory side-effects, burning sensation and taste abnormalities were observed. CONCLUSION: Topical tazarotene may be a valuable therapeutic tool in the treatment of hyperkeratotic OLP.  相似文献   
6.
BACKGROUND: Epitopes of blood group A antigen can be enzymatically cleaved from red cells (RBCs), but the extent of cleavage required for normal survival in allogeneic blood transfusion recipients is unknown. Therefore, the cleavage rates were studied for A antigen epitope binding of 1) complement-activating anti-A, 2) Dolichos biflorus anti- A, lectin, and 3) hemagglutinating anti-A during incubation with a purified alpha-N-acetylgalactosaminidase, E.C. 3.2.1.49 (alpha- GalNAc'ase). STUDY DESIGN AND METHODS: Suspensions of group A RBCs were incubated with alpha-GalNAc'ase. Cells were removed at intervals, washed, and tested for loss of binding by monoclonal, polyclonal, and complement-activating anti-A, D. biflorus anti-A1 lectin, and Ulex europaeus anti-H lectin. RESULTS: A epitopes binding D. biflorus lectin were highly susceptible to alpha-GalNAc'ase; simultaneously with their loss, binding with U. europaeus lectin emerged. Loss of complement- mediated hemolysis was slower. A epitopes binding hemagglutinating anti- A were most resistant. Cleavage of A epitopes from membrane glycosphingolipids with short oligosaccharide chains was similarly resistant. Rates of cleavage from A1 and A2 RBCs were similar. CONCLUSION: RBC epitopes of blood group A differ in susceptibility to cleavage and biologic reactivity, which suggests that subsets mediating important biologic functions exist on functionally and topographically distinct membrane glycoconjugates.  相似文献   
7.
BACKGROUND: Concern over the theoretical possibility of disease transmission via blood from donors who develop Creutzfeldt-Jakob disease has led to proposals to exclude older individuals from donating plasma for further manufacture into pooled plasma donations. The impact of extending this age-deferral policy to blood donors was examined with respect to the risk for known transmissible viruses. STUDY DESIGN AND METHODS: Demographic characteristics and confirmed prevalence rates (/10(5) first-time donations) and incidence rates (/10(5) person-years for repeat donors) for viral markers were compared for donors < 50 years old (n = 1,259,805 [85%]) and > or = 50 years old (n = 219,856 [15%]) and for donors < 60 years old (n = 1,409,176 [95%]) and > or = 60 years old (n = 70,485 [5%]). Incidence rates were combined with infectious window-period estimates for each virus, to calculate the risk of virus transmission per 10(6) donations. RESULTS: Unadjusted prevalence rates were significantly greater for younger than for older donor groups for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), and hepatitis C virus (HCV) (p < or = 0.05). Incidence rates (and transmission risk estimates) for HBsAg were significantly higher in the < 50 donor group than in the > or = 50 group (p < or = 0.05), and those for HIV, human T-lymphotropic virus, and HCV were not significantly higher (p > 0.05). Blanket removal of donors over the age of 50 would potentially lead to the following significant increases in the risk of infected units: HIV, 12 percent; HCV, 21 percent; and hepatitis B virus (HBsAg), 22 percent. CONCLUSION: Removal of donors over the age of 60 would not significantly affect the risk of infected units. Deferral of donors > or = 50 years of age from whole-blood donations for unfounded concerns about Creutzfeldt-Jakob disease could have adverse effects on both blood availability and safety.  相似文献   
8.
The safety and efficacy of cefepime, a new broad-spectrum, semisynthetic parenteral cephem antibiotic, were evaluated in an open trial at a single hospital. Seventy patients were treated with cefepime: 44 had lower respiratory tract infections, 4 had urinary tract infections, and 22 had skin or soft tissue infections. Of 65 clinically evaluable patients, 64 (98%) had satisfactory responses. No mortality or superinfections occurred. Of 57 respiratory and urinary tract pathogens, 54 (95%) were eradicated and 3 (5%) persisted after therapy. Five bacteremias (two with Streptococcus pneumoniae and one each with Staphylococcus aureus, Proteus mirabilis, and a coagulase-negative staphylococcus) were eradicated. MICs ranged from 1 to 8 micrograms/ml for 13 S. aureus and 9 Pseudomonas aeruginosa isolates and were less than or equal to 0.125 micrograms/ml for 10 streptococcal isolates. Adverse effects occurred in two patients: transient diarrhea and Clostridium difficile toxin in the stool in one patient and loose bowel movements and increased transaminases in the other patient. Cefepime appeared to be well tolerated in humans and was effective against a wide range of isolates, including S. aureus and P. aeruginosa.  相似文献   
9.
Purpose

To compare the accuracy of Contrast-Enhanced Spectral Mammography (CESM), MG, US, and breast MRI in estimating the size of breast lesions requiring surgery. The postoperative histology size of the lesion was used as the gold standard.

Material and methods

Two hundred thirty-three non-benign lesions in 189 patients were included in the analyses. All the selected patients underwent CESM and at least one other conventional diagnostic exam (US, MG, or MRI). Subsequently, all the patients underwent surgery preceded by cytological/histological examination. The largest diameter of the lesion at imaging was measured by a radiologist with more than 10 years’ experience and then compared with the size of the lesion in the histological sample at the surgery (gold standard).

Results

Among the 233 breast lesions, 196 were evaluated with US, 206 with MG and 160 with MRI. We found no statistically significant differences between size measurements using CESM and MRI compared with the measurements at the surgery (p value 0.63 and 0.51), whereas a significant difference was found for MG and US (p?<?0.001).

Conclusion

CESM is a reliable method for estimating the size of breast lesions: its performance seems superior to US and MG and comparable to MRI.

  相似文献   
10.
Background The last decades have witnessed an increasing interest for the psychosocial aspects of chronic skin diseases, such as psoriasis. Nonetheless, systematic assessments of the impact of psoriasis on patients’ lives are rarely done in daily clinical practice. The existing instruments are mostly meant to be completed by patients alone, and rarely comprise a graphical representation of the results. Objective  To develop a questionnaire allowing both a quick assessment of the impact of psoriasis on patients and, at the same time, an intuitive graphic visualization of the outcome of the test. Methods A preliminary version of an Italian questionnaire aimed to assess the global impact of psoriasis on patients, meant to be filled in together by the patient and the dermatologist and to produce visual, intuitive results, was developed through focus groups. The instrument was then the object of a Delphi survey addressed to a panel of experts, to assess both the need of possible improvements of the questionnaire (in terms of the formulations of the questions and of the domains to be explored) and the usefulness of the questionnaire. Results A 10‐item questionnaire in Italian, taking into account different aspects of the burden of psoriasis on the patient, was developed. The answers are given on a 10‐point visual analogue scale and graphically represented on a disc as a polygon. Conclusions A formal validation of the questionnaire and a study to assess potential clinical and psychological benefits of a systematic implementation of the instrument in daily practice are planned.  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