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   813篇
  免费   25篇
  国内免费   22篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   17篇
基础医学   89篇
口腔科学   22篇
临床医学   62篇
内科学   151篇
皮肤病学   15篇
神经病学   52篇
特种医学   95篇
外科学   233篇
综合类   8篇
预防医学   18篇
眼科学   3篇
药学   60篇
肿瘤学   21篇
  2022年   3篇
  2021年   5篇
  2020年   6篇
  2019年   9篇
  2018年   13篇
  2017年   9篇
  2016年   9篇
  2015年   11篇
  2014年   18篇
  2013年   32篇
  2012年   49篇
  2011年   58篇
  2010年   50篇
  2009年   36篇
  2008年   74篇
  2007年   57篇
  2006年   53篇
  2005年   42篇
  2004年   27篇
  2003年   18篇
  2002年   19篇
  2001年   10篇
  2000年   6篇
  1998年   19篇
  1997年   20篇
  1996年   16篇
  1995年   13篇
  1994年   14篇
  1993年   13篇
  1992年   6篇
  1991年   4篇
  1990年   4篇
  1989年   11篇
  1988年   12篇
  1987年   8篇
  1986年   12篇
  1985年   7篇
  1984年   5篇
  1983年   3篇
  1982年   7篇
  1981年   3篇
  1980年   8篇
  1979年   5篇
  1978年   6篇
  1977年   8篇
  1976年   14篇
  1975年   9篇
  1973年   3篇
  1972年   5篇
  1971年   3篇
排序方式: 共有860条查询结果,搜索用时 15 毫秒
1.
Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients.  相似文献   
2.
Summary— In the present study we have compared the steady state biopharmaceutic characteristics of four diltiazem once daily controlled release capsules: Mono-Tildiem LP 300® (300 mg), Adizem® XL (300 mg)1, Cardizem® (300 mg) and Dilacor® (240 mg). Sixteen healthy male volunteers (aged 22.9 ± 3.3 years, range 19–31 years) completed an open label, multiple oral dose, randomized, four-period crossover study without a washout period in between. The volunteers received each diltiazem formulation once daily for four days. Trough diltiazem and metabolites plasma concentrations were determined on days 3 and 4. The 24-h plasma concentration-time profiles were assessed after the dose on day 4 of each period. The following steady state pharmacokinetic parameters for diltiazem were calculated: the minimum plasma concentration (cmin), the maximum plasma concentration (cmax), the time to reach that concentration (tmax), the time interval during which the plasma concentration exceeds 50% of cmax (t50), the area under the plasma concentration-time curve (AUC72–96) and the peak-to-trough fluctuation (PTF). For the metabolites of diltiazem, N-mono-desmethyl-diltiazem (NDM) and desacetyldiltiazem (DAD), AUC72–96 (AUCNDM and AUCDAD) and the ratio metabolite/parent compound were calculated. Steady state was achieved on day 3. Except one, all controlled release formulations have satisfactory controlled release properties allowing once daily administration. However, significant (P < 0.05) differences were found between the pharmacokinetic characteristics which do not allow exchange of the various formulations. Concentrations well below 50 ng·mL-1 in the morning hours were observed for Dilacor® (240 mg) and Adizem® XL (300 mg), which could be a disadvantage of these formulations as it is well-known that ischaemic events occur at a higher rate during that part of the day. The plasma concentration profiles of NDM and DAD, the major circulating metabolites, parallel the plasma concentration profiles for the parent compound. From a clinical point of view, all treatments were well tolerated.  相似文献   
3.
4.
This study measured the carrying angle of the elbow joint in full extension in 600 students, using the supplementary angle to that between the longitudinal axis of the arm and that of the forearm. The mean carrying angle was 12.88°±5.92: 10.97°±4.27 in men and 15.07°±4.95 in women. The carrying angle changes with skeletal growth and maturity. The angle is always greater on the side of the dominant hand. We confirmed the inverse relationship between the carrying angle and the intertrochanteric diameter. Also, the type of constitution influences the value of the carrying angle, especially in women.  相似文献   
5.
Three cases (two male, one female) of annular pancreas are presented, which were found and operated on within the last three decades. Diagnosis was made using imaging techniques, especially ultrasonography and computed tomography. In two cases there was incomplete obstruction, while in the other obstruction was complete. It is characteristic that in the case of complete obstruction the annular portion of the pancreas attached to a circular band of connective tissue, while in the two cases of incomplete obstruction there was a complete ring of pancreatic tissue. In all cases surgical intervention was needed in order to create a bypass. In the first case gastroenterostomy and truncal vagotomy was performed, in the second latero-lateral duodeno-jejunostomy and in the third latero-lateral antropyloroduodeno-jejunostomy. The embryology and morphology of the annular pancreas, the morphology of its duct system, diagnosis, differential diagnosis and the surgical treatment of this rare condition are reviewed.  相似文献   
6.
7.
8.
Axonal damage is now being recognized as a common finding in multiple sclerosis (MS) lesions and a cause of irreversible neurological damage. Attempts to identify markers of early axonal damage are of great significance. This prompted us to examine the microtubule-associated protein tau in the cerebrospinal fluid (CSF) of patients with MS vs. controls. Tau was measured by double antibody sandwich ELISA. Increased CSF tau levels were found in MS as compared to controls (medians 249.6 and 135 pg/ml respectively, p<0.001). Half of the MS patients presented with levels above the upper limit of the controls. A significant increase vs. controls was found in both relapsing-remitting and progressive subtypes. These data may indicate axonal impairment in a subpopulation of MS patients and may provide a tool for the estimation of axonal damage during life.  相似文献   
9.
Head and neck cancer (HNC) comprises a heterogeneous variety of malignant tumors, characterized by a relatively high tumor mutation burden. Previous data have revealed that immune system dysfunction appears to serve a key role in the development and progression of HNC and established immunosuppression is vital for evading the host immune response. Despite progress in chemotherapy and radiotherapy, the survival rate of patients with HNC is still low. Therefore, the present review discusses the development of novel immunotherapy approaches based on the various immune cell signaling routes that trigger drug resistance and immunosuppression. Additionally, the present review discusses the epigenetic alterations, including DNA methylation, histone modifications, chromatin remodeling and non-coding RNAs that drive and support HNC progression. Furthermore, the role of cancer-associated fibroblasts, tumor macrophages and myeloid cells in tumor-related immunosuppression are considered. Specifically, the molecular immune-related mechanisms in the tumor microenvironment, which lead to decreased drug sensitivity and tumor relapse, and strategies for reversing drug resistance and targeting immunosuppressive tumor networks are discussed. Deciphering these molecular mechanisms is essential for preclinical and clinical investigations in order to enhance therapeutic efficacy. Furthermore, an improved understanding of these immune cell signaling pathways that drive immune surveillance, immune-driven inflammation and tumor-related immunosuppression is necessary for future personalized HNC-based therapeutic approaches.  相似文献   
10.

Background

Studies dealing with laparoscopic colectomy for cancer have reached conflicting results in regards to various inflammatory cytokines. Most of them have not examined potential differences with the open procedures at later postoperative days, when the immunologic advantage of laparoscopic surgery would be more demanding to demonstrate (for earlier administration of adjuvant treatment). The aim of this work is to detect differences of proinflammatory cytokines between conventional and laparoscopic colectomy for cancer.

Patients and methods

30 patients who underwent laparoscopic colectomy were age, sex, and preoperative stage-matched with 30 patients treated by open surgery. C-reactive protein (CRP), interleukin (IL)-1, -6, and -8, and interferon (IFN)-γ serum levels were measured preoperatively, at 24 h, and at the 7th postoperative day (POD).

Results

CRP and IL-6 postoperative values (24 h and 7th POD) were significantly higher than baseline for both groups (p = 0.001), but the respective values at the 7th POD were less than at 24 h (p = 0.001). IL-1 and -8 levels did not show any differences between assessment timepoints. A higher IFN-γ measurement was demonstrated at 24 h compared with baseline for the laparoscopic group only (p = 0.03). This difference was not maintained at the 7th POD. IFN-γ levels at 24 h and the 7th POD were significantly less for the open compared with the laparoscopic group of patients (p = 0.001). No correlation was revealed between measured serum values and age, sex, tumor location, or stage.

Conclusions

This matched case–control study verifies the already reported lack of differences regarding IL-1. Controversy still exists on likely IL-6 differences. The inadequately studied IL-8 does not seem to play an important role in immunologic differences. The immunologically beneficial IFN-γ, produced by the principal effectors of cell-mediated immunity Th1 cells, seems to have a more active presence following laparoscopic colectomy, potentially contributing to an immunologic “advantage” by counteracting “harmful” cytokines, such as IL-1.
  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