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   1797篇
  免费   82篇
  国内免费   10篇
耳鼻咽喉   8篇
儿科学   37篇
妇产科学   101篇
基础医学   210篇
口腔科学   3篇
临床医学   170篇
内科学   540篇
皮肤病学   56篇
神经病学   101篇
特种医学   41篇
外科学   161篇
综合类   19篇
一般理论   1篇
预防医学   56篇
眼科学   57篇
药学   173篇
中国医学   58篇
肿瘤学   97篇
  2023年   7篇
  2022年   6篇
  2021年   24篇
  2020年   14篇
  2019年   22篇
  2018年   33篇
  2017年   13篇
  2016年   20篇
  2015年   43篇
  2014年   51篇
  2013年   72篇
  2012年   124篇
  2011年   98篇
  2010年   91篇
  2009年   65篇
  2008年   101篇
  2007年   149篇
  2006年   135篇
  2005年   119篇
  2004年   88篇
  2003年   84篇
  2002年   86篇
  2001年   85篇
  2000年   55篇
  1999年   62篇
  1998年   27篇
  1997年   13篇
  1996年   15篇
  1995年   11篇
  1994年   16篇
  1993年   9篇
  1992年   28篇
  1991年   25篇
  1990年   24篇
  1989年   7篇
  1988年   14篇
  1987年   19篇
  1986年   7篇
  1985年   13篇
  1984年   6篇
  1983年   3篇
  1981年   1篇
  1977年   1篇
  1975年   2篇
  1974年   1篇
排序方式: 共有1889条查询结果,搜索用时 15 毫秒
31.
32.

Purpose:

The purpose of this study is to identify the possible factors for preserving the eyes after late or suboptimally treated endogenous endophthalmitis secondary to Klebsiella pneumoniae (KP) liver abscess.

Methods:

A retrospective chart review was conducted for patients admitted with KP liver abscess from January 1991 to June 2012.

Results:

Six hundred and ninety-three patients with KP liver abscess were recorded, in which endophthalmitis was identified in 53 cases (65 eyes, 8.29%). Diabetes was significantly associated with the development of endophthalmitis (p = 0.014). Eleven eyes received their last ocular treatment ≥10 days and final vision ≥ counting fingers, and were defined as benign type KP endophthalmitis. The absence of diabetes was the only consistent candidate factor for benign type KP endophthalmitis.

Conclusion:

A lack of ongoing diabetes is an important factor in preserving eyes with late or suboptimally treated endogenous endophthalmitis second to KP liver abscess.  相似文献   
33.
Several studies have shown cardiovascular benefit in treating hypercholesterolemia with HMG-CoA reductase inhibitor. However, in addition to the lowering of cholesterol, the beneficial effects of this inhibitor reflect other pharmacological activities. Whether these beneficial effects are partly mediated by changes in fibrinolytic factors remains to be proven, since clinical studies on the effects of HMG-CoA reductase inhibitors on fibrinolytic factors have not yielded consistent results. The purpose of this study was to evaluate the effects of fluvastatin on fibrinolytic factors in hypercholesterolemic patients. After 6 weeks on a low-fat, low-cholesterol diet, 23 outpatients known to have primary hypercholesterolemia with low density lipoprotein cholesterol (LDL-C) > or = 130 mg/dl with at least 2 risk factors or fasting LDL-C > or = 160 mg/dl were selected for the study. Venous blood samples were collected at baseline and at 8 weeks after fluvastatin therapy (40 mg/day) to measure of tissue plasminogen activator (t-PA), plasminogen activators inhibitor-1 (PAI-1), fibrinogen, D-dimer and lipid profile. After 8 weeks of therapy, fluvastatin reduced serum cholesterol by 11% (261.9 mg/dl vs 233.2 mg/dl, P < 0.01) and LDL-C by 22% (191.9 mg/dl vs 149.3 mg/dl, P < 0.01). D-dimer was significantly decreased (0.38 ng/L vs 0.28 ng/L, P = 0.02) and tPA, PAI-1 and fibrinogen tended to decrease after therapy. Fluvastatin therapy improved fibrinolytic profile; the result of this study may in part explain the benefit of HMG-CoA reductase inhibitor on cardiovascular system other than lipid lowering.  相似文献   
34.
Intratumor injection of OK-432, a biological response modifier, in the treatment of small HCC was studied in 7 inoperable patients. After evaluation with ultrasound (US), computed tomography (CT), angiography and US-guided biopsy, implantation of a steel coil in the tumor, intratumor injection was performed under US guidance. After completion of the treatment, liver biopsy and image studies were again done to evaluate the extent of tumor necrosis. One patient was alive and well without recurrence 19 months after treatment. Four had recurrent tumors at different site of the liver 4 months, 9 months, 9 months and 8 months later. Two died of progressive malignancy 3 months and 8 months later. In the 6 patients with elevated serum alpha-fetoprotein (AFP) levels, 4 had decreased AFP after treatment, and the 2 mortalities had steadily increased AFP. The most common side effects are fever and chills. Transient abdominal pain with elevated transaminase activities, cough with hemoptysis, and vomiting were seen in 1 case each. After treatment, the biopsy specimens showed total necrosis of HCC. Although the T4/T8 ratio of peripheral blood was increased as compared with that before treatment in 4 cases, peritumoral cytotoxic T lymphocyte and monocyte infiltration were seen in one specimen only, and another 7 examined specimens showed negative staining with monoclonal antibodies of T cells. We conclude that intratumor injection of OK-432 is an alternative treatment for small HCC in inoperable cases. The effectiveness may be due to the direct tumoricidal mechanism of OK-432.  相似文献   
35.
A 45-year-old male received wedge resection for his small hepatocellular carcinoma in April 1989 and extended right lobectomy for tumor recurrence 8 months later. Unfortunately, recurrent hepatic tumor with lung metastases were found 18 months after the second operation. Both the hepatic and pulmonary recurrent tumors were resected and transcatheter arterial embolization was added for the residual hepatic tumors. He remained symptom free for another 18 months. However, mediastinal lymphadenopathy, superior vena cava thrombus with superior vena cava syndrome, cardiac and brain metastases developed subsequently. He died of increased intracranial pressure. It is rare for hepatocellular carcinoma to have mediastinal metastases, superior vena cava thrombus and superior vena cava syndrome.  相似文献   
36.
High-sensitivity C-reactive protein (hs-CRP) is positively associated with the prevalence of coronary artery disease by epidemiologic data. Prospective studies indicate that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors reduced the plasma hs-CRP concentration and the risk of recurrent coronary events after myocardial infarction. Type 2 diabetes is associated with high mortality risk of coronary heart disease and this high risk may be involved in the inflammatory factors. We have therefore conducted a prospective study to assess whether simvastatin can rapidly reduce the plasma hs-CRP concentration in type 2 diabetic patients with hyperlipidemia. Seventeen type 2 diabetic patients with hyperlipidemia were enrolled in the study after 6 weeks on a lipid-lowering diet. Fourteen patients completed the study, taking simvastatin 20 mg daily for 8 weeks. Fasting blood samples were collected from each patient before and after 8-week administration of simvastatin. In response to 8-week administration of simvastatin, hs-CRP levels significantly decreased from 0.312±0.057 to 0.193±0.045 mg/dl (P<.01). Plasma LDL cholesterol also decreased significantly from 130±9 to 74±3 mg/dl (P=.001). This study shows that plasma hs-CRP concentration can be reduced by 8-week administration of simvastatin in type 2 diabetic patients with hyperlipidemia.  相似文献   
37.
S H Kuo  J C Sheu  D S Chen  J L Sung  C C Lin  H C Hsu 《Liver》1987,7(6):359-363
To demonstrate DNA clonal heterogeneity of hepatocellular carcinomas (HCC), the DNA histographic pattern of both primary HCCs and their recurrent or metastatic lesions were studied among 36 patients (33 men and 3 women). Thirty-six paired aspirations or imprints taken from primary, recurrent or metastatic lesions were stained, using the modified Feulgen method, and the DNA content was measured with a scanning microdensitometer at a wavelength of 550 nm. Paired aspirations or imprints taken from different parts of the same HCC were examined in 17 cases; the DNA distribution patterns were similar in 15 (88%) and differed in only two (12%). A similar DNA histogram was also shown among different tumors in 10 (71%) of 14 patients with multiple HCCs, with a DNA ploidy discrepancy in only four (29%). Two of two subcutaneous metastases and two of three recurrent tumors showed DNA distribution patterns similar to those in their primary HCCs. In summary, a DNA clonal heterogeneity of HCC was found in 19% (7/36). In contrast, the similar DNA histographic patterns found in most instances among different parts of the HCC and between the primary and recurrent or metastatic lesions suggest that HCC may derive from a single cell clone in the majority of cases.  相似文献   
38.
The growth rate of 31 asymptomatic hepatocellular carcinomas (diameter less than or equal to 5 cm) discovered in 28 patients by a prospective screening program was determined by real-time ultrasonography over 36-860 days. Except for one tumor that shrank on follow-up, the doubling time ranged from 29 to 398 days, with a median of 117 days, an arithmetic mean of 136 days, and a geometric mean of 110 days. In 17 tumors with more than two measurements, the growth rate remained exponential in nine, declined in growth in seven, and showed an initial lag period in one. Doubling time correlated with initial tumor diameter but was independent of the patient's age, sex, hepatitis B surface antigen status, tumor location, liver function tests, stage of liver cirrhosis, histologic type, or grade of malignancy. Although initial alpha-fetoprotein levels did not correlate well with growth rate, in 14 patients with an exponential increase of serum alpha-fetoprotein, the alpha-fetoprotein doubling time was closely related to the tumor doubling time. Based on the above data, the median detectable subclinical period of hepatocellular carcinoma was deduced to be 3.2 yr, and the suitable screening interval for its early detection in our area was 4-5 mo.  相似文献   
39.
In response to aggravation by activated microglia, IL‐13 can significantly enhance ER stress induction, apoptosis, and death via reciprocal signaling through CCAAT/enhancer‐binding protein alpha (C/EBP‐α) and C/EBP‐beta (C/EBP‐β). This reciprocal signaling promotes neuronal survival. Since the induction of cyclooxygenase‐2 (COX‐2) and peroxisome proliferator‐activated receptor gamma/heme oxygenase 1 (PPAR‐γ/HO‐1) by IL‐13 plays a crucial role in the promotion of and protection from activated microglia, respectively; here, we investigated the role of IL‐13 in regulating C/EBPs in activated microglia and determined its correlation with neuronal function. The results revealed that IL‐13 significantly enhanced C/EBP‐α/COX‐2 expression and PGE2 production in LPS‐treated microglial cells. Paradoxically, IL‐13 abolished C/EBP‐β/PPAR‐γ/HO‐1 expression. IL‐13 also enhanced ER stress‐evoked calpain activation by promoting the association of C/EBP‐β and PPAR‐γ. SiRNA‐C/EBP‐α effectively reversed the combined LPS‐activated caspase‐12 activation and IL‐13‐induced apoptosis. In contrast, siRNA‐C/EBP‐β partially increased microglial cell apoptosis. By NeuN immunochemistry and CD11b staining, there was improvement in the loss of CA3 neuronal cells after intrahippocampal injection of IL‐13. This suggests that IL‐13‐enhanced PLA2 activity regulates COX‐2/PGE2 expression through C/EBP‐α activation. In parallel, ER stress‐related calpain downregulates the PPAR‐γ/HO‐1 pathway via C/EBP‐β and leads to aggravated death of activated microglia via IL‐13, thereby preventing cerebral inflammation and neuronal injury.  相似文献   
40.
Postherpetic neuralgia is the most common complication of herpes zoster which is caused by a reactivation of latent varicella zoster virus. The pathogenesis of postherpetic neuralgia may involve peripheral and central mechanisms. Reported risk factors for postherpetic neuralgia include female gender, old age, diminished cell-mediated immunity and nutritional deficiencies. Based on our clinical observation which revealed that peptic ulcer disease (PUD) is one of the common comorbidities in patients with postherpetic neuralgia, we hypothesize that herpes zoster patients with PUD may be at a greater risk for the development of postherpetic neuralgia due to their impaired cellular immunity and depressed nutritional status. Major causes of PUD include Helicobacter pylori infection and usage of ulcerogenic medications. Patients with H. pylori infection may develop T cell dysfunctions and nutritional deficiencies including vitamin C, iron, cobalamin, carotenes and alpha-tocopherol. Ulcerogenic medications such as nonsteroidal anti-inflammatory drugs and steroids have been found not only to be ulcerogenic but also immunosuppressive to T cells. In addition, usage of steroids and nonsteroidal anti-inflammatory drugs may cause deficiencies of alpha-tocopherol, carotenes, cobalamin, iron, zinc and vitamin C. Vitamin C, carotenes and alpha-tocopherol are anti-inflammatory and the major oxidant scavengers in the aqua phase and biomembranes. Deficiencies of these nutrients may induce dysregulated inflammation and oxidative damage leading to neuropathic pain in patients with herpes zoster. Furthermore, nutrient deficiencies including zinc, iron, cobalamin and vitamin C are associated with dysregulation of Ca(v)3.2 T-channels and N-methyl-d-aspartate receptors, upregulation of nitric oxide synthase, the increase of nitric oxide formation and dysfunction of central norepinephrine inhibitory pain pathway. Prospective cohort studies are suggested to test the hypothesis. We further propose that a follow-up study that contains two groups of herpes zoster patients, i.e., with or without gastroendoscopy-proven PUD, be conducted to determine their incidence of postherpetic neuralgia. In addition, despite of the high proportion of zoster patients having been treated with antiviral therapies, prevention and treatment of postherpetic neuralgia remain challenging in clinical practice. The potential risk of postherpetic neuralgia in zoster patients with PUD could mean that physicians need to pay more attention to the comorbidity - PUD in patients with herpes zoster and treat PUD earlier in order to prevent the development of postherpetic neuralgia.  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