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   1850篇
  免费   93篇
  国内免费   26篇
耳鼻咽喉   10篇
儿科学   33篇
妇产科学   19篇
基础医学   304篇
口腔科学   47篇
临床医学   129篇
内科学   346篇
皮肤病学   37篇
神经病学   259篇
特种医学   27篇
外科学   151篇
综合类   5篇
预防医学   243篇
眼科学   11篇
药学   179篇
中国医学   6篇
肿瘤学   163篇
  2023年   8篇
  2022年   19篇
  2021年   44篇
  2020年   24篇
  2019年   34篇
  2018年   35篇
  2017年   30篇
  2016年   38篇
  2015年   42篇
  2014年   72篇
  2013年   92篇
  2012年   135篇
  2011年   144篇
  2010年   74篇
  2009年   60篇
  2008年   134篇
  2007年   139篇
  2006年   136篇
  2005年   126篇
  2004年   154篇
  2003年   129篇
  2002年   111篇
  2001年   14篇
  2000年   8篇
  1999年   13篇
  1998年   17篇
  1997年   18篇
  1996年   9篇
  1995年   6篇
  1994年   8篇
  1993年   9篇
  1992年   6篇
  1991年   4篇
  1990年   8篇
  1989年   6篇
  1988年   5篇
  1987年   6篇
  1986年   5篇
  1985年   4篇
  1984年   5篇
  1983年   3篇
  1982年   6篇
  1981年   3篇
  1979年   3篇
  1978年   4篇
  1977年   3篇
  1976年   3篇
  1972年   2篇
  1967年   2篇
  1961年   1篇
排序方式: 共有1969条查询结果,搜索用时 15 毫秒
11.
Although excessive alcohol consumption is by far the most frequent cause of recurrent acute pancreatitis (AP) cases, specific therapy is still not well established to prevent recurrence. Generally, psychological therapy (e.g., brief intervention (BI)) is the cornerstone of cessation programs; however, it is not yet widely used in everyday practice. We conducted a post-hoc analysis of a prospectively collected database. Patients suffering from alcohol-induced AP between 2016 and 2021 received 30 min BI by a physician. Patient-reported alcohol consumption, serum gamma-glutamyl-transferase (GGT) level, and mean corpuscular volume (MCV) of red blood cells were collected on admission and at the 1-month follow-up visit to monitor patients’ drinking habits. Ninety-nine patients with alcohol-induced AP were enrolled in the study (mean age: 50 ± 11, 89% male). A significant decrease was detected both in mean GGT value (294 ± 251 U/L vs. 103 ± 113 U/L, p < 0.001) and in MCV level (93.7 ± 5.3 U/L vs. 92.1 ± 5.1 U/L, p < 0.001) in patients with elevated on-admission GGT levels. Notably, 79% of the patients (78/99) reported alcohol abstinence at the 1-month control visit. Brief intervention is an effective tool to reduce alcohol consumption and to prevent recurrent AP. Longitudinal randomized clinical studies are needed to identify the adequate structure and frequency of BIs in alcohol-induced AP.  相似文献   
12.
Developments in nanotechnology and in the formulation of liposomal systems provide the opportunity for cosmetic dermatology to design novel delivery systems. Determination of their physico-chemical parameters has importance when developing a nano-delivery system. The present study highlights some technological aspects/characteristics of liposomes formulated from egg or soy lecithins for topical use. Alterations in the pH, viscosity, surface tension, and microscopic/macroscopic appearance of these vesicular systems were investigated. The chemical composition of the two types of lecithin was checked by mass spectrometry. Caffeine, as a model molecule, was encapsulated into multilamellar vesicles prepared from the two types of lecithin: then zeta potential, membrane fluidity, and encapsulation efficiency were compared. According to our observations, samples prepared from the two lecithins altered the pH in opposite directions: egg lecithin increased it while soy lecithin decreased it with increased lipid concentration. Our EPR spectroscopic results showed that the binding of caffeine did not change the membrane fluidity in the temperature range of possible topical use (measured between 2 and 50 °C). Combining our results on encapsulation efficiency for caffeine (about 30% for both lecithins) with those on membrane fluidity data, we concluded that the interaction of caffeine with the liposomal membrane does not change the rotational motion of the lipid molecules close to the head group region. In conclusion, topical use of egg lecithin for liposomal formulations can be preferred if there are no differences in the physico-chemical properties due to the encapsulated drugs, because the physiological effects of egg lecithin vesicles on skin are significantly better than that of soy lecithin liposomes.  相似文献   
13.
14.
Hormonal replacement therapy (HRT) in postmenopausal women has been shown to increase both triglyceride (TG) and high-density lipoprotein (HDL) cholesterol levels. To better understand the effects of conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA), the 2 most commonly prescribed hormones in HRT, on the different subpopulations of TG-rich and HDL lipoproteins, we conducted a placebo-controlled, double-blind, randomized, crossover study consisting of 3 different phases in 14 postmenopausal women. The 3 phases, each 8-week long, included: (1) placebo, (2) CEE 0.625 mg/d, and (3) CEE 0.625 mg/d and MPA 2.5 mg/d. Slight and statistically nonsignificant elevations in TG levels were observed during the CEE treatment. While very-low-density lipoprotein (VLDL) cholesterol levels were not significantly affected by CEE and CEE + MPA, both HRT treatments lowered remnant lipoprotein (RLP) cholesterol (-14% and -37%, respectively). Compared with placebo, CEE caused a significant increase in HDL, HDL(2), apolipoprotein (apo) A-I, LpAI, alpha1, and prealpha1 levels (12%, 27%, 17%, 26%, 60%, and 102%, respectively). The combination therapy blunted the CEE effect on all HDL parameters, resulting in HDL, HDL(2), and LpAI levels being no longer significantly different from placebo. Apo A-I levels and alpha1, and prealpha1 levels were still significantly higher than placebo (+11%, +50%, and +112%, respectively). These results indicate that HRT has beneficial effects on RLP levels and that, while the estrogen component of HRT has a beneficial effect on the HDL subpopulations mostly associated with coronary heart disease (CHD) protection, MPA partially inhibits this effect.  相似文献   
15.
16.
Background and aimsThe aim of the present study was to evaluate the circadian rhythm of blood pressure pattern in obese children, and to investigate if the lack of normal diurnal rhythm of blood pressure is associated with cardiovascular risk factors.Methods and results73 obese children (body weight [mean ± SD]: 89.0 ± 17.8 kg; age [mean ± SD]: 14.2 ± 2.3 years), 42 dippers and 31 non-dippers were investigated. Following ambulatory blood pressure monitoring (ABPM), physical fitness testing was performed on a treadmill. Physical working capacity at 130, -150, -170 beat/min (PWC-130, -150, -170), resting and peak oxygen consumption (VO2rest, VO2peak) were determined.Forty-two percent of obese children were non-dipper. PWC-130 (74.8 ± 48.8 watts; 48.0 ± 38.5 watts), PWC-150 (132.9 ± 52.1 watts; 104.2 ± 49.3 watts), PWC-170 (185.9 ± 49.5 watts; 154.9 ± 53.4 watts) and VO2rest, ([mean ± SD]: 0.29 ± 0.08 L/min; 0.26 ± 0.07 L/min), and VO2 peak (2.77 ± 0.61 L/min; 2.44 ± 0.62 L/min) were significantly lower in the non-dipper group, as compared to dippers (p < 0.05). The prevalence of hypertension, on the basis of ABPM, was significantly higher in the non-dipper group (45.2% vs 83.9%, p < 0.001). This is due to increased prevalence of masked hypertension in the non-dipper group (19.0% vs 32.3%, p < 0.001).ConclusionThe normal circadian variation of the blood pressure is frequently absent in obese children. Most of the non-dipper obese children are hypertensive, and their physical fitness is decreased.  相似文献   
17.
Bacterial pyrogens, capable of penetrating dialyzer membranes, are responsible for a systemic inflammatory reaction in hemodialysis patients. Dialyzer reuse, involving rinsing of the dialyzer with pyrogen-containing water, may exacerbate this situation. Studies of the mechanism of action of endotoxin suggest that it irreversibly damages the vascular endothelium. The novel endotoxin removal method described here, is based on affinity-binding of endotoxin by the adsorbent ClarEtox, a USP Class VI-certified resin that is the active component of the medical device DialGuard. Under standard hemodialysis operating conditions, challenge of DialGuard with Pseudomonas maltophilia supernatant-spiked dialysate, containing 35-193 EU/ml endotoxin, resulted in endotoxin levels below 0.05 EU/ml in the treated dialysate. DialGuard was able to decrease endotoxin concentrations in the dialysate from a range of 2.39-8.49 to <0.005 EU/ml. DialGuard supports high fluid velocities at low back pressures and can be sanitized using the heat sanitization cycle of hemodialysis machines. DialGuard offers a simple, user-friendly way to reduce the concentration of endotoxin in dialysate and water for dialysis at a low cost.  相似文献   
18.
Yawalkar N  Ferenczi K  Jones DA  Yamanaka K  Suh KY  Sadat S  Kupper TS 《Blood》2003,102(12):4059-4066
Cutaneous T-cell lymphoma (CTCL) is a malignancy of skin-homing T cells. A major feature of CTCL is profound immunosuppression, such that patients with advanced mycosis fungoides or Sézary syndrome have been compared with patients with advanced HIV disease and are susceptible to opportunistic infection. The etiology of this immunosuppression is unclear. We analyzed peripheral blood T cells of patients with CTCL with stage I to IV disease, using a sensitive beta-variable complementarity-determining region 3 spectratyping approach. Our data revealed a profound disruption of the complexity of the T-cell repertoire, which was universally observed in patients with advanced disease (stages III and IV), and present in up to 50% of patients with early-stage disease (stages I and II). In most patients, multiple monoclonal and oligoclonal complementarity-determining region 3 (CDR3) spectratype patterns in many different beta-variable families were seen. Equally striking was a reduction of normal T cells (as judged by absolute CD4 counts) across multiple beta-variable families. In general, CTCL spectratypes were reminiscent of advanced HIV spectratypes published elsewhere. Taken together, these data are most consistent with a global assault on the T-cell repertoire in patients with CTCL, a process that can be observed even in early-stage disease.  相似文献   
19.
OBJECTIVE: To gain insight into the mechanisms of the antiinflammatory effect of tumor necrosis factor alpha (TNFalpha)-induced protein 6 (Tnfip6) in arthritis, using Tnfip6-deficient animals. METHODS: TNFalpha-stimulated gene 6 (TSG-6) coding for Tnfip6 was disrupted. Tnfip6-deficient mice were backcrossed into proteoglycan-induced arthritis (PGIA)-susceptible BALB/c mice, and arthritis was induced by systemic immunization with cartilage proteoglycan (PG). Thioglycollate-induced sterile peritonitis was also assessed, to monitor the early events of neutrophil extravasation in wild-type and Tnfip6-deficient mice in the presence or absence of treatment with recombinant murine Tnfip6. RESULTS: The onset of PGIA was similar, but progression and severity were significantly greater, in Tnfip6-deficient mice compared with wild-type BALB/c mice. However, this was not associated with enhanced T or B cell responses to cartilage PGs, but rather, an early and more extensive infiltration of the synovium with neutrophil leukocytes was the most prominent histopathologic feature of PGIA in Tnfip6-deficient mice. This was accompanied by elevated serum levels of interleukin-6 and amyloid A, and significantly increased activities of the enzymes plasmin, myeloperoxidase, and neutrophil elastase in the inflamed paw joints of Tnfip6-null mice, when compared with that of the wild-type littermates. Loss of control over several components of inflammation resulted in extensive and rapid cartilage degradation, bone erosion, joint ankylosis, and deformities in Tnfip6-null animals. In support of the antiinflammatory effect of Tnfip6 via the inhibition of polymorphonuclear (PMN) cell efflux, neutrophil invasion during thioglycollate-induced peritonitis was 2-fold higher in Tnfip6-deficient animals than in wild-type animals, but was dramatically suppressed by intravenous injection of recombinant murine Tnfip6. CONCLUSION: Tnfip6 is a multifunctional antiinflammatory protein that is produced at the site of inflammation and can be retained by the hyaluronan-rich extracellular matrix. A major effect of Tnfip6 is the inhibition of the extravasation of PMN cells, predominantly neutrophils, into the site of inflammation, most likely via a CD44/hyaluronan/Tnfip6-mediated blocking mechanism.  相似文献   
20.
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