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   2364篇
  免费   82篇
  国内免费   18篇
耳鼻咽喉   75篇
儿科学   194篇
妇产科学   99篇
基础医学   166篇
口腔科学   190篇
临床医学   159篇
内科学   404篇
皮肤病学   47篇
神经病学   168篇
特种医学   61篇
外科学   551篇
综合类   39篇
预防医学   74篇
眼科学   51篇
药学   127篇
中国医学   10篇
肿瘤学   49篇
  2025年   1篇
  2024年   5篇
  2023年   16篇
  2022年   21篇
  2021年   49篇
  2020年   30篇
  2019年   42篇
  2018年   53篇
  2017年   34篇
  2016年   79篇
  2015年   82篇
  2014年   101篇
  2013年   125篇
  2012年   185篇
  2011年   165篇
  2010年   112篇
  2009年   86篇
  2008年   144篇
  2007年   155篇
  2006年   174篇
  2005年   174篇
  2004年   149篇
  2003年   104篇
  2002年   125篇
  2001年   55篇
  2000年   42篇
  1999年   35篇
  1998年   13篇
  1997年   19篇
  1996年   15篇
  1995年   12篇
  1994年   11篇
  1993年   3篇
  1992年   1篇
  1991年   7篇
  1990年   6篇
  1989年   8篇
  1988年   6篇
  1987年   1篇
  1986年   5篇
  1985年   6篇
  1978年   1篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1970年   1篇
  1959年   1篇
排序方式: 共有2464条查询结果,搜索用时 15 毫秒
101.
AIM: To assess the effects of anti-epileptic drugs on renal tubular function. METHODS: Urinary N-acetyl-beta-D-glucosaminidase activity was measured in 114 epileptic children (mean age 5.6 +/- 1.1 years) who were undergoing monotherapy with valproate (n = 46), carbamazepine (n = 34), lamotrigine (n = 13) and combined therapy with valproate+carbamazepine (n = 21). RESULTS: The urinary N-acetyl-beta-D-glucosaminidase index of valproate (P < 0.01), carbamazepine (P < 0.05) and polytherapy group (P < 0.01) were significantly elevated when compared with that of the control group. No significant difference in N-acetyl-beta-D-glucosaminidase levels was found between the lamotrigine group and the control subjects. We found that the distribution of the N-acetyl-beta-D-glucosaminidase values of patients depended significantly on the length of therapy (P < 0.01). The level of urinary excretion of N-acetyl-beta-D-glucosaminidase was significantly higher in the patients who were taking long-term treatment (>10 years) with valproate, carbamazepine and combined therapy than those taking therapy shorter than 10 years (P < 0.01). The mean serum concentrations of valproate and carbamazepine were 68.7 +/- 17.44 microg/mL and 5.41 +/- 1.23 microg/mL, respectively. There was a significant correlation between the serum concentration of valproate and urinary N-acetyl-beta-D-glucosaminidase levels (r = 0.44, P < 0.01). There was also a significant correlation between the serum concentration of carbamazepine and N-acetyl-beta-D-glucosaminidase excretion (r = 0.52, P < 0.01). CONCLUSION: The present study demonstrated that in patients treated with valproate and carbamazepine, an impairment of tubular function can be present, whereas lamotrigine does not cause any significant change.  相似文献   
102.
Leptin is an adipose tissue-derived peptide hormone, which acts as a satiety factor to reduce appetite by interactions with hypothalamic neurons. The other possible physiological functions of leptin are still unclear. In this study, we have evaluated dose-dependent effect of leptin on penicillin-induced epileptiform activity, analyzed by electrocorticogram (ECoG). The epileptiform activity was induced by microinjection of penicillin into the left sensorymotor cortex. Thirty minutes after penicillin injection, 1, 2 or 10 microg of leptin was administrated intracerebroventricularly (i.c.v.). Leptin (1, 2 or 10 microg) alone did not significantly change the spike amplitudes in non-penicillin pretreated control animals. One or two micrograms of leptin significantly increased the frequency of epileptiform activity in the penicillin-pretreated animals. The high dose of leptin (10 microg) did not significantly change either amplitude or frequency of epileptiform activity. One microgram i.c.v. leptin was the most effective dose in changing of frequency on penicillin-induced epileptiform activity. The proconvulsant effects of leptin appeared 90 min after leptin (1 and 2 microg) injection. These data indicate that leptin increases the frequency of penicillin-induced epileptic activity. We speculate that this action of leptin might suggest that leptin may be a proconvulsant substance.  相似文献   
103.
Reattachment of the amputated fingertips as composite grafts has been performed for distal levels in children, with high rates of good outcome, but the majority of the reports emphasized that this procedure had success rates only up to 50% in adults. Several techniques to enhance composite graft take in adults have been defined. In this study, a technique to enhance nonmicrosurgical replantation of amputated fingertips as composite grafts is presented.Twenty-three patients were treated with this technique, 20 of which were adults. An area of skin on the amputation margin of the stump was deepithelized, and the amputated part was defatted to reattach the piece as a cap composite graft and to increase the contact area. The patients were evaluated after the operations regarding functional and esthetic outcome.Success rates of 86.95% in total and 85% in adults were achieved, with acceptable sensibility (with a mean value of 7.26 mm for the 2-point discrimination), minimal shortening (a mean value of 6.80 mm), and satisfactory esthetic outcome using this technique.  相似文献   
104.
BACKGROUND: Heart transplantation is an important therapeutic option for patients with end-stage disease, but is associated with major pulmonary complications. PATIENTS AND METHODS: We retrospectively reviewed the posttransplant follow-up of 34 orthotopic heart transplant recipients. RESULTS: Two of the 34 patients died of cardiac failure in the early postoperative period. Among the surviving patients, 10 (31.3%) developed pulmonary complications, all within the first 6 months: hospital-acquired bacterial pneumonia in five, fungal pneumonia in three, posttransplant lymphoproliferative disease in one, and community-acquired pneumonia in one patient. None of the patients developed transplantation-related malignancy. The overall mortality was 35.3%. Pneumonia-related mortality rate of 14.7% was due to early-onset nosocomial pneumonias, which were caused by bacterial and opportunistic microorganisms. Extrapulmonary causes of mortality were cardiac failure, meningitis, septicemia, and acute rejection. Cytomegalovirus antigenemia in the first month was associated with a poor prognosis. The frequency of pulmonary complications was higher among older patients and those who developed moderate rejection in the first month (P=.014 and P=.036, respectively). CONCLUSION: Pulmonary infections after heart transplantation occurred more frequently during the first 6 months posttransplantation, accounting for a significant portion of the posttransplantation mortality.  相似文献   
105.
Yapar N  Uysal U  Yucesoy M  Cakir N  Yuce A 《Mycoses》2006,49(2):134-138
In recent years, a progressive increase in the frequency of nosocomial candidaemia has been observed, especially among the critically ill or immunocompromised patients. The aim of this study was to evaluate the trend in incidence of candidaemia together with potential risk factors in an 850-bed Turkish Tertiary Care Hospital in a 4-year period. A total of 104 candidaemia episodes were identified in 104 patients. The overall incidence was 0.56 per 1000 hospital admissions and the increase in incidence of candidaemia from 2000 to 2003 was found to be statistically significant (P = 0.010). Candida albicans was the most common species (57.7%) and non-albicans species accounted for 42.3% of all episodes. The most common non-albicans Candida sp. isolated was C. tropicalis (20.2%) followed by C. parapsilosis (12.5%). The most frequent risk factors possibly associated with the candidaemia were previous antibiotic treatment (76.9%), presence of central venous catheter (71.2%) and total parenteral nutrition (55.8%). Our results show the fact that the incidence of candidaemia caused by non-albicans species is frequent and increasing significantly, although the most common isolated Candida species were C. albicans and further investigations are necessary to evaluate the mechanisms of increasing incidence of candidaemia caused by non-albicans species.  相似文献   
106.
Infections in immunocompromised children can stem from bacteria, fungi, viruses, or protozoa, but most importantly, from the host's endogenous bacterial flora. Disseminated infection caused by Trichosporon species is one of the emerging mycoses in neutropenic patients, particularly when they are treated for haematological malignancy with cytotoxic and immunosuppressive chemotherapy. We report a 15-year-old boy with acute lymphoblastic leukaemia, whose Trichosporon mucoides infection was successfully treated with lipid complex amphotericin B plus 5-fluorocytosine.  相似文献   
107.
Multicellular tumor spheroids (MTS) are three-dimensional structural forms of tumors grown in vitro in the laboratory. In this study, the aim was to determine the regulation of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) expressions on MTS in response to treatment with the commonly used anti-cancer drugs Doxorubicin and Docetaxel. The spheroids were generated using the "liquid overlay" technique. The distribution of both iNOS and eNOS was detected using indirect immunohistochemistry, while the expression of both iNOS and eNOS was measured using Western blots. Additionally, S-phase analysis using 5-bromo-2'-deoxyuridine (BrdU) was done on the MTS after treatment with doxorubicin, docetaxel, and a combination of the two. The Griess method was used to measure nitric oxide (NO) production in the cells. An increase in iNOS immunoreactivity and a decrease in eNOS immunoreactivity were observed after doxorubicin treatment, when compared with the other groups. Furthermore, upregulation of iNOS and downregulation of eNOS were detected in doxorubicin-treated cells using Western blotting. Insignificant iNOS expression was observed in all of the groups, and it was particularly low in the control and drug combination groups. NO production was also found to be significantly high after docetaxel treatment, and cell proliferation decreased after doxorubicin treatment. In conclusion, chemotherapy influences NOS activity differently with the presence of different drugs. The results with iNOS show that doxorubicin is a more effective drug than docetaxel, and a drug combination may play a helpful role in the suppression of tumorigenicity and cancer metastasis. Interestingly, eNOS expression increased after the addition of both docetaxel and the drug combination, and it was found to negatively correlate with the histological grade of the tumor. Therefore, analyzing the expression of both iNOS and eNOS might be very useful for targeting the treatment of breast carcinoma and obtaining better information on prognosis.  相似文献   
108.
Tumor heterogeneity is an important feature that is especially involved in tumor aggressiveness. Multicellular tumor spheroids (MTS) may provide some benefits in different steps for investigation of the aggregation, organization, differentiation, and network formation of tumor cells in 3D space. This model offers a unique opportunity for improvements in the capability of a current strategy to detect the effect of an appropriate anticancer agent. The aim of this study was to investigate the cellular interactions and morphological changes following chemotherapy in a 3D breast cancer spheroid model. Distribution of the gap junction protein "connexin-43" and the tight junction protein "occludin" was investigated by immunohistochemistry. Cellular interactions were examined by using transmission and scanning electron microscopies as well as light microscopy with Giemsa staining after treating cells with doxorubicin, docetaxel, and doxorubicin/docetaxel combination. Statistical analyses showed significant changes and various alterations that were observed in all groups; however, the most prominent effect was detected in the doxorubicin/docetaxel combination group. Distinct composition as a vessel-like structure and a pseudoglandular pattern of control spheroids were detected in drug-administered groups. Immunohistochemical results were consistent with the ultrastructural changes. In conclusion, doxorubicin/docetaxel combination may be more effective than the single drug usage as shown in a 3D model. The MTS model has been found to be an appropriate and reliable method for the detection of the changes in the expression of cellular junction proteins as well as other cellular proteins occurring after chemotherapy. The MTS model can be used to validate the effects of various combinations or new chemotherapeutic agents as well as documentation of possible mechanisms of new drugs.  相似文献   
109.
110.
OBJECTIVE: The aim of this prospective study was to investigate the effects of electrohydraulic extracorporeal shock wave lithotripsy (ESWL) on the transient evoked otoacoustic emissions (TEOAEs) of the patients on whom ESWL was applied for urinary stones. METHODS: The study group consisted of 10 patients (7 male, 3 female) with unilateral urinary lithiasis on whom ESWL was applied in one course and 20 of their ears. The control group was chosen from patients who attended the Otolaryngology and Urology departments. Ten patients (7 male, 3 female) without urinary stones and ear problems and 20 of their ears constituted the control group. Only patients with normal hearing levels were included in the study. TEOAEs were recorded before the ESWL application (B-ESWL), on the first day (A-ESWL-1), and on day 15 (A-ESWL-15). RESULTS: At B-ESWL, the mean stimulus for the control group was significantly higher than that of the study group. Three kilohertz percentage values were significantly decreased on A-ESWL-1. The difference between A-ESWL-1 and A-ESWL-15 and between B-ESWL and A-ESWL-15 of the study group at 3.0 kHz% was not significant. CONCLUSION: It was thought that the reason for only temporary damage at 3.0 kHz was a result of the resonance effect of the external auditory canal. It was concluded that no damage on the other frequencies was due to protective earheadings and short exposure time to the noise. Since all of our patients had protective earheadings on both ears during the ESWL procedure, they may have been protected from any permanent damage of the inner ear and hairy cells of the cochlea.  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