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   2905篇
  免费   164篇
  国内免费   17篇
耳鼻咽喉   58篇
儿科学   80篇
妇产科学   31篇
基础医学   451篇
口腔科学   39篇
临床医学   182篇
内科学   752篇
皮肤病学   45篇
神经病学   217篇
特种医学   116篇
外科学   564篇
综合类   6篇
预防医学   68篇
眼科学   17篇
药学   159篇
中国医学   3篇
肿瘤学   298篇
  2023年   13篇
  2022年   25篇
  2021年   59篇
  2020年   32篇
  2019年   42篇
  2018年   55篇
  2017年   50篇
  2016年   65篇
  2015年   52篇
  2014年   78篇
  2013年   126篇
  2012年   169篇
  2011年   187篇
  2010年   101篇
  2009年   88篇
  2008年   162篇
  2007年   177篇
  2006年   195篇
  2005年   187篇
  2004年   190篇
  2003年   172篇
  2002年   171篇
  2001年   46篇
  2000年   39篇
  1999年   46篇
  1998年   60篇
  1997年   44篇
  1996年   31篇
  1995年   33篇
  1994年   25篇
  1993年   30篇
  1992年   40篇
  1991年   24篇
  1990年   32篇
  1989年   21篇
  1988年   18篇
  1987年   19篇
  1986年   24篇
  1985年   24篇
  1984年   20篇
  1983年   16篇
  1982年   9篇
  1981年   13篇
  1980年   11篇
  1979年   13篇
  1978年   10篇
  1977年   5篇
  1975年   6篇
  1974年   7篇
  1967年   4篇
排序方式: 共有3086条查询结果,搜索用时 15 毫秒
1.
2.
BACKGROUND: In patients with chronic kidney disease (CKD), although strong associations have been observed between malnutrition and atherosclerosis, the relationship between serum albumin concentration and angiographic changes of coronary artery disease (CAD) remains poorly explored. The goal of the present study was, in patients with CKD, to clarify the relationship between the angiographic severity of CAD and serum albumin concentration reflecting either inflammation or nutrition or both. METHODS: In this study, 100 end-stage renal disease (ESRD) patients were enrolled, who commenced long-term dialysis therapy at our hospital and underwent coronary angiography within 3 months of the first haemodialysis (HD) session. Mean age was 63+/-11 years, 20% of the subjects were female and 62% had diabetes. Severity of CAD was evaluated in terms of (i) number of vessels exhibiting CAD (>or=75% stenosis) and (ii) Gensini score (GS). Clinical characteristics and laboratory findings were recorded at initiation of long-term HD therapy. We then evaluated a possible association with the presence and degree of CAD. RESULTS: Sixty-four patients exhibited signs of CAD. Forty-one among them (64%) had multivessel disease. On univariate logistic regression analysis, age, diabetes and hypoalbuminaemia were significantly associated with multivessel CAD. Univariate linear regression analysis demonstrated a positive correlation of age and diabetes with GS, and an inverse correlation of BMI and serum albumin level with GS. Stepwise regression analysis showed age and serum albumin level to be independently associated with multivessel CAD and GS. The ROC curves demonstrated best cut-off levels of age and albumin for predicting multivessel CAD to be 70 years and 3.15 g/dl, respectively. CONCLUSION: Hypoalbuminaemia at the initiation of dialysis is an important predictor of advanced CAD, particularly in male and in diabetic patients. It may reflect mainly a state of inflammation. However, malnutrition as a confounding factor cannot be entirely excluded.  相似文献   
3.
4.
Coiled bodies and interfascicular threads are conspicuous white matter abnormalities of brains of patients with progressive supranuclear palsy (PSP). Both structures are argyrophilic and immunoreactive for the microtubule-binding protein tau. This report concerns the ultrastructural localization of interfascicular threads and their relationship to coiled bodies in five PSP patients. We showed for the first time that abnormal tubules with a 13- to 15-nm diameter and fuzzy outer contours were the common structures of coiled bodies in the oligodendroglial perikarya and of interfascicular threads. Moreover, the tubules were immunolabeled by anti-tau antibodies. The abnormal tau-positive tubules of interfascicular threads were located in the inner loop of the myelin sheath. Our study further indicated that the thread-like structures in the white matter comprised, at least in part, oligodendroglial processes, and that they were also present in gray matter. We consider that the formation of coiled bodies in the perikarya and of interfascicular threads represents a common cytoskeletal abnormality of the oligodendroglia of PSP patients. Moreover, even though the white matter alterations of PSP resemble those of corticobasal degeneration, there are certain ultrastructural differences in the abnormal oligodendroglial tubules of the two diseases. Received: 4 October 1996 / Accepted: 6 December 1996  相似文献   
5.
6.
A 49-year-old Japanese man presented with chronic granulomatous uveitis in his left eye. Later he developed macular subretinal neovascularisation. The chest x-ray showed bilateral hilar lymphadenopathy. Bronchoscopy and gallium-67 scanning were positive, PPD skin test negative, and serum angiotensin converting enzyme (ACE) levels increased. Ophthalmoscopy and fluorescein angiography of the left eye showed perivasculitis, retinochoroidal exudates, snow banking, and vitreous opacity. On these findings, the diagnosis of sarcoidosis was made. Treatment was based on topical corticosteroids, mydriatics, beta blockers, and oral carbonic anhydrase inhibitors. After 15 months the visual acuity decreased in the left eye, and a neovascular membrane was observed in the macula. Fluorescein angiography confirmed subretinal neovascularisation. Almost two years later the patient still has the neovascular membrane in his left eye.  相似文献   
7.
8.
Objective.To identify the clinicopathological and chemoresistant factors predicting the response to neoadjuvant chemotherapy and the patient prognosis in high-risk cervical carcinomas.Methods.We retrospectively reviewed 47 patients with locally advanced or bulky cervical carcinoma treated with two courses of intraarterial infusion of cisplatin, doxorubicin, mitomycin C, and 5-fluorouracil (5-FU), followed by radical hysterectomy at our hospital between 1988 and 1995. Expressions of the chemoresistance-related proteins, such as P-glycoprotein, glutathioneS-transferase π (GST-π), and proliferating cell nuclear antigen (PCNA) in the tumor cells, were examined by immunohistochemistry using pretreatment biopsy specimens. These results were compared with the chemotherapeutic response, which was evaluated by magnetic resonance imaging (MRI) and histopathology. Outcome of the patients was also studied.Results.Chemotherapeutic effect of either complete (CR) or partial (PR) response on MRI was obtained in 36 of the 47 (86%) patients. Poor response to chemotherapy was significantly correlated with P-glycoprotein expression (P< 0.005) and low PCNA labeling (P< 0.05), but not GST-π expression in the tumor cells. Independent prognostic factors for patient survival were parametrial involvement and lymph node metastasis. Neither the expression of GST-π nor PCNA was correlated with the patient survival.Conclusion.Assessment of the expression of P-glycoprotein and PCNA is potentially useful for the prediction of tumor response to neoadjuvant chemotherapy for cervical carcinomas.  相似文献   
9.
We investigated the relative effects of 0.5, 1.0, 1.5, 2.0 MAC halothane and enflurane, and concurrent noxious stimulus on hepatic blood flow and oxygen consumption in 14 mongrel dogs randomly divided into groups of seven each. Hepatic arterial and portal venous blood flow (HABF and PVBF, respectively) were measured continuously using ultrasonic transit time flow meter. Mean arterial blood pressure (MAP), cardiac index (CI), hepatic oxygen supply, and hepatic oxygen consumption (H O 2) were measured. Halothane significantly deceased HABF, but not PVBF in a dose dependent manner. Enflurane did not affect HABF and PVBF significantly. MAP and CI decreased in both groups, with halothane producing more marked decreases than enflurane. H O 2 did not change with enflurane, but did with halothane, producing significant differences, with halothane being greater at 1.5, 2.0 MAC. A noxious stimulus only caused minor change in blood flow. The results suggest that liver blood flow and oxygen consumption are affected differently by halothane and enflurane and that halothane has a stronger tendency to cause an imbalance between liver oxygen supply and consumption than dose enflurane.(Masaki E, Yasuda N, Tanifuji Y et al.: Effect of halothane and enflurane on hepatic blood flow and oxygen consumption in dogs. J Anesth 3: 118–122, 1989)  相似文献   
10.
Eye infections caused by adenovirus (Ad) often result in nosocomial infections and community epidemics with significant rates of morbidity. No antiviral agent effective against Ad is yet available for clinical use. Therefore, early diagnosis is still the mainstay for patient management and the prevention of epidemics. A multiplex PCR assay based on amplification of a combination of the fiber and hexon genes which can identify the six important oculopathogenic serotypes of Ads (Ad serotype 3[Ad3], Ad4, Ad7, Ad8, Ad19, and Ad37) in a single-tube amplification reaction was developed. Ad serotypes could be distinguished by the different amplicon sizes. The assay correctly identified prototype strains as well as isolates in clinical specimens. In comparison with a previously described PCR-restriction fragment polymorphism method, our assay gave unequivocal results for clinical specimens. Our multiplex PCR has the potential to serve as a rapid and cost-effective tool for the typing of important ocular Ads.  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