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   20728篇
  免费   1220篇
  国内免费   154篇
耳鼻咽喉   248篇
儿科学   564篇
妇产科学   724篇
基础医学   2305篇
口腔科学   588篇
临床医学   1728篇
内科学   4108篇
皮肤病学   428篇
神经病学   961篇
特种医学   806篇
外国民族医学   15篇
外科学   3554篇
综合类   375篇
现状与发展   2篇
一般理论   11篇
预防医学   1747篇
眼科学   582篇
药学   1955篇
中国医学   148篇
肿瘤学   1253篇
  2024年   17篇
  2023年   269篇
  2022年   848篇
  2021年   1235篇
  2020年   674篇
  2019年   838篇
  2018年   1132篇
  2017年   665篇
  2016年   699篇
  2015年   698篇
  2014年   975篇
  2013年   1168篇
  2012年   1665篇
  2011年   1786篇
  2010年   1017篇
  2009年   737篇
  2008年   1022篇
  2007年   1019篇
  2006年   949篇
  2005年   919篇
  2004年   792篇
  2003年   722篇
  2002年   647篇
  2001年   154篇
  2000年   123篇
  1999年   121篇
  1998年   81篇
  1997年   80篇
  1996年   79篇
  1995年   67篇
  1994年   64篇
  1993年   52篇
  1992年   53篇
  1991年   70篇
  1990年   65篇
  1989年   55篇
  1988年   56篇
  1987年   51篇
  1986年   42篇
  1985年   42篇
  1984年   43篇
  1983年   38篇
  1982年   35篇
  1981年   24篇
  1980年   22篇
  1978年   18篇
  1977年   15篇
  1976年   18篇
  1975年   15篇
  1973年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
113.
This study investigated the role of KATP channels in morphine‐induced antinociception and hepatic oxidative stress in acute and inflammatory pain. The KATP channel modulators (KATP channel opener, diazoxide 100 mg/kg, p.o, and KATP channel blocker, glibenclamide, 3 mg/kg i.p.) were administered with morphine (80 mg/kg, i.p.). Antinociception was assessed by the tail‐flick and formalin tests in rats and measured by the area under the curve values and the maximum percent effect for 3 h. The indices of hepatic oxidative stress: glutathione, glutathione peroxidase, and malondialdehyde were then determined in the liver homogenates obtained from the treated animals. In both tests, glibenclamide antagonized morphine‐induced antinociception, whereas diazoxide augmented it in the tail‐flick test only. In the formalin test, glibenclamide alone has a significant hyperalgesic effect, whereas diazoxide decreased the number of flinches. Coadministration of glibenclamide with morphine antagonized the hepatotoxic effect of morphine in both animal models. In the tail‐flick test, glibenclamide administered alone significantly increased malondialdehyde's level. Coadministration of diazoxide with morphine increased glutathione level in the formalin test. Diazoxide administered alone exacerbated the hepatic oxidative stress in both animal models. These findings suggest a role of KATP channel modulators on morphine‐induced antinociception and hepatic oxidative stress. The administration of glibenclamide may prevent morphine‐induced hepatotoxicity. The effectiveness of diazoxide in the management of pain is limited due to its deleterious effect on the liver. However, the interaction of the KATP channel modulators with morphine depends on the differential sensitivity to the pain stimulus.  相似文献   
114.
Obesity is often associated with chronic inflammatory state which contributes to the development of insulin resistance (IR) and type 2 diabetes mellitus (T2DM). This study investigated the effects of single and combined administration of atorvastatin (ATOR, lipid‐lowering drug) and losartan (LOS, angiotensin receptor antagonist) on metabolic disorders and inflammatory status that are implicated in the development of T2DM with the use of pioglitazone (PIO) as a standard antidiabetic drug. T2DM was induced in male rats by high‐fat diet (HFD) feeding for 16 weeks. Oral administrations of ATOR (10 mg/kg), LOS (20 mg/kg), PIO (3 mg/kg), their binary combinations, or vehicle were started in the last 4 weeks. Fasting serum glucose, oral glucose tolerance, fasting serum insulin, IR, serum lipid profile, serum TNF‐α and body composition index were determined. Results showed that all drugs and their combinations had positive impact effect on all measured parameters, and better results were achieved from binary drug combinations than administration of each drug alone. Combination of PIO with either ATOR or LOS provided better improvements on T2DM‐associated metabolic abnormalities and inflammatory status with respect to each drug alone. However, the most pronounced effects of drugs and their combinations regarding the above parameters were attributed to LOS + PIO combination. In conclusion, this study indicates that combination of ATOR + PIO and, in particular, LOS + PIO can be used as promising effective therapies in the management of HFD‐induced T2DM. This concept may be attributed to the combined effects of the respective monotherapies to improve lipid profile, insulin sensitivity, and TNF‐α level.  相似文献   
115.
Objectives:To elucidate the risk factors for hospital admission among COVID-19 patients with type 2 diabetes mellitus (T2DM).Methods:This retrospective study was conducted at the Prince Sultan Military Medical City, Riyadh, Saudi Arabia between May 2020 and July 2020. Out of 7,260 COVID-19 patients, 920 were identified as T2DM. After the exclusion process, 806 patients with T2DM were included in this analysis. Patients’ data were extracted from electronic medical records. A logistic regression model was performed to estimate the risk factors of hospital admission.Results:Of the total of 806 COVID-19 patients with T2DM, 48% were admitted in the hospital, 52% were placed under home isolation. Older age between 70-79 years (OR [odd ratio] 2.56; p=0.017), ≥80 years (OR 6.48; p=0.001) were significantly more likely to be hospitalized compared to <40 years. Similarly, patients with higher HbA1c level of ≥9% compared to <7%; (OR 1.58; p=0.047); patients with comorbidities such as, hypertension (OR 1.43; p=0.048), cardiovascular disease (OR 1.56; p=0.033), cerebrovascular disease (OR 2.38; p=0.016), chronic pulmonary disease (OR 1.51; p=0.018), malignancy (OR 2.45; p=0.025), chronic kidney disease (CKD) IIIa, IIIb, IV (OR 2.37; p=0.008), CKD V (OR 5.07; p=0.007) were significantly more likely to be hospitalized. Likewise, insulin-treated (OR 1.46; p=0.03) were more likely to require hospital admission compared to non-insulin treated patients.Conclusion:Among COVID-19 patients with diabetes, higher age, high HbA1c level, and presence of other comorbidities were found to be significant risk factors for the hospital admission.  相似文献   
116.
The role of CC chemokine receptor 5 (CCR5) in islet allograft rejection   总被引:6,自引:0,他引:6  
Chemokines are important regulators in the development, differentiation, and anatomic location of leukocytes. CC chemokine receptor 5 (CCR5) is expressed preferentially by CD4(+) T helper 1 (Th1) cells. We sought to determine the role of CCR5 in islet allograft rejection in a streptozotocin-induced diabetic mouse model. BALB/c islet allografts transplanted into CCR5(-/-) (C57BL/6) recipients survived significantly longer (mean survival time, 38 +/- 8 days) compared with those transplanted into wild-type control mice (10 +/- 2 days; P < 0.0001). Twenty percent of islet allografts in CCR5(-/-) animals without other treatment survived >90 days. In CCR5(-/-) mice, intragraft mRNA expression of interleukin-4 and -5 was increased, whereas that of interferon-gamma was decreased, corresponding to a Th2 pattern of T-cell activation in the target tissues compared with a Th1 pattern observed in controls. A similar Th2 response pattern was also observed in the periphery (splenocytes responding to donor cells) by enzyme-linked immunosorbent spot assay. We conclude that CCR5 plays an important role in orchestrating the Th1 immune response leading to islet allograft rejection. Targeting this chemokine receptor, therefore, may provide a clinically useful strategy to prevent islet allograft rejection.  相似文献   
117.
In this report, the authors review the case of a man with a neurocutaneous syndrome. He presented with an intracerebral melanocytoma associated with a blue nevus of the scalp; its location and its appearance during childhood supported the diagnosis of a nevus of Ota. Meningeal melanocytomas are increasingly being diagnosed, but remain rare. Primary meningeal malignant melanoma is the first differential diagnosis to eliminate. Despite their common embryonic origin. the association of a melanocytoma with a nevus of Ota is rare. A nevus of Ota exhibits the same melanocytic proliferation and affects the trigeminal nerve territory. An ocular effect is not always observed. In contrast to an ocular lesion, a nevus of Ota rarely transforms into a malignant melanoma. It is found only among caucasians. During 4 years of follow-up review after surgery, the patient remained asymptomatic. Other than antiepileptic therapy, he received no complementary treatment and cerebral imaging revealed no evidence of recurrence.  相似文献   
118.
BACKGROUND: Mitral stenosis after mitral valve repair for non-rheumatic mitral regurgitation is rare. METHODS: From 1990 to 1999, 478 patients had mitral valve repair for myxomatous and 40 patients had mitral valve repair for ischemic mitral regurgitation. The Carpentier annuloplasty ring (Edwards Lifesciences, Irvine, CA) was used in 72 patients, the Duran ring (Medtronic, Minneapolis, MN) in 152, a posterior band in 221 and no ring or band in 73 patients. RESULTS: Four patients developed mitral stenosis late after mitral valve repair: 2 for myxomatous disease and 2 for ischemic mitral regurgitation. All 4 patients had Duran annuloplasty rings (sizes 25 to 31). The diagnosis of mitral stenosis was made by Doppler echocardiography. The mitral valve area in these 4 patients decreased from 2.7 cm2 (range, 2.3 to 3.2 cm2) early postoperatively to 0.85 cm2 (0.4 to 1.2 cm2) after a mean follow-up of 66 months (range, 38 to 110 months). Three patients had mitral valve replacement and the etiology of the mitral stenosis was the same in all patients (ie, pannus overgrowth on the annuloplasty ring with extension onto both leaflets rendering them stiff and immobile). The fourth patient had a mitral valve area of 1.2 cm2, which was mildly symptomatic with normal pulmonary artery pressure, and this patient has not had reoperation. CONCLUSIONS: Mitral stenosis may develop after mitral valve repair for myxomatous disease or ischemic mitral regurgitation when a Duran ring is used for annuloplasty. The stenosis is caused by pannus on the annuloplasty ring with extension onto the leaflets.  相似文献   
119.

Background

Severe brain trauma leads to an activation of the immune system. To this date, neither the exact perturbation of the specific immune reaction induced by the traumatic brain injury (TBI), nor the interactions leading to the infiltration of peripheral immune cells into the brain are fully understood.

Patients and methods

Serum was collected from 17 patients with TBI and a long bone fracture, 24 patients with an isolated long bone fracture and from healthy individuals. The effect of the serum on normal human monocytes and T-lymphocytes was tested in vitro by assessing proliferation and expression of surface markers, chemokine receptors and cytokines.

Results

Serum collected from patients with a TBI and a long bone fracture increased the expression of the chemokine receptor CCR4 in monocytes when compared to patients with an isolated long bone fracture. Extending this comparison to T-lymphocytes, the serum from TBI patients induced lower proliferation rates and decreased expression of the pro-inflammatory cytokine TNF-α, while simultaneously increasing the secretion of immune-modulatory cytokines (IL-4, IL-10 and TGF-β) (p < 0.05).

Conclusion

Patients with a TBI release currently unknown soluble factors into the circulating blood that up regulate expression of chemokine receptor CCR4 in peripheral blood monocytes whilst concurrently inducing expression of immunosuppressive cytokines by activated T-lymphocytes.  相似文献   
120.
Awake thoracic epidural anaesthesia as the sole anaesthetic technique was successfully employed for two high risk surgical patients with chronic obstructive pulmonary disease undergoing abdominal surgery. The procedure was tolerated well and the anaesthetic technique which has been shown to reduce intra-operative and post-operative cardiac, respiratory and gastrointestinal complications, may have significantly contributed to the prompt, complication free recovery experienced by both patients. We report two cases of awake major abdominal surgery in two high-risk surgical patients with severe pulmonary disease, performed effectively under thoracic epidural anaesthesia as a sole technique. The first case was an elective open sigmoid colectomy in a sixty one year old cancerous patient with chronic obstructive pulmonary disease [COPD] and recent thoracotomy for a wedge resection of a bronchial adenocarcinoma [pT1NoMx]. The second case was an emergency open cholecystectomy in an adult patient with end-stage COPD. Reviewing the literature, no similar cases were reported recently.  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