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   8944篇
  免费   397篇
  国内免费   65篇
耳鼻咽喉   96篇
儿科学   163篇
妇产科学   65篇
基础医学   1055篇
口腔科学   201篇
临床医学   562篇
内科学   2635篇
皮肤病学   124篇
神经病学   523篇
特种医学   320篇
外科学   1552篇
综合类   24篇
一般理论   1篇
预防医学   153篇
眼科学   141篇
药学   483篇
中国医学   12篇
肿瘤学   1296篇
  2024年   9篇
  2023年   79篇
  2022年   193篇
  2021年   301篇
  2020年   151篇
  2019年   200篇
  2018年   229篇
  2017年   189篇
  2016年   242篇
  2015年   228篇
  2014年   291篇
  2013年   359篇
  2012年   651篇
  2011年   714篇
  2010年   423篇
  2009年   333篇
  2008年   568篇
  2007年   595篇
  2006年   586篇
  2005年   546篇
  2004年   523篇
  2003年   506篇
  2002年   492篇
  2001年   70篇
  2000年   78篇
  1999年   81篇
  1998年   105篇
  1997年   75篇
  1996年   41篇
  1995年   58篇
  1994年   47篇
  1993年   44篇
  1992年   36篇
  1991年   43篇
  1990年   28篇
  1989年   32篇
  1988年   31篇
  1987年   11篇
  1986年   30篇
  1985年   28篇
  1984年   23篇
  1983年   18篇
  1982年   15篇
  1981年   10篇
  1980年   10篇
  1979年   12篇
  1977年   16篇
  1976年   7篇
  1975年   8篇
  1969年   7篇
排序方式: 共有9406条查询结果,搜索用时 0 毫秒
121.
A 30-year-old woman was admitted because of persistent and severe hemoptysis in November 2005. She had been given a diagnosis of interstitial pneumonia (IP) and pulmonary aspergilloma in 2001, and she was treated with oral prednisolone and itraconazole. However she had persistent and intractable hemoptysis. Multi-detector row computed tomography (MDCT) revealed that hemoptysis from the right upper lobe did not originate in bronchial arteries, but the abnormal branches of the right subclavian artery. Surgery was not performed because of her pulmonary function, but she was successfully treated by non-bronchial arterial coil embolization. At 10 months after the embolization, hemoptysis has not recurred. MDCT was very useful for diagnosing the cause of hemoptysis and selective nonbronchial arterial coil embolization might be helpful in treating intractable or refractory hemoptysis.  相似文献   
122.
BACKGROUND: Ventricular tachyarrhythmias (VT/VF) are 1 of the most important factors determining the prognosis of patients with heart failure (HF). Although priority is given to implantable cardioverter defibrillator (ICD) therapy for the prevention of sudden cardiac death, electrophysiologic-study (EPS)-guided preventive therapy could be important for reducing the number of cardiac events. METHODS AND RESULTS: Of 864 patients with a history of HF, an EPS was performed in 168 and 121 had inducible VT/VF. Under the basic therapy of an ICD, additional catheter ablation was attempted for 95 of 124 monomorphic VT foci in 74 patients, and 78 of the VT were successfully ablated. The prognoses were compared among 5 patient groups with different results for the EPS and catheter ablation: (1) success group (n=43), (2) failure group (n=15), (3) not attempted group (n=16), (4) VF group (n=47), and (5) no inducible VT/VF group. During a follow-up period of 31+/-22 months, the incidence of VT/VF was lower in the success and no inducible VT/VF groups than in the other groups (p=0.0018), although a significant difference was not observed for the total deaths. CONCLUSION: EPS-guided preventive therapy using an ICD and catheter ablation can be useful, at least for the reduction of arrhythmic events in patients with HF.  相似文献   
123.
124.
Multiple myeloma (MM) is a plasma‐cell neoplasm that can cause renal disorders. Renal lesions in MM can present with a very rare pathological manifestation involving a specific monoclonal immunoglobulin (Ig). We report the case of a 33‐year‐old woman who had edema, fatigue, elevated serum creatinine levels, hypoalbuminemia, and hypercholesterolemia. She had persistent hematuria and proteinuria lasting 3 years. Serum protein electrophoresis showed an M‐spike, and serum immunofixation demonstrated the presence of monoclonal IgG λ. She had proteinuria in the nephrotic range, and a monoclonal λ fragment was present on urine immunofixation. Renal biopsy showed proliferative glomerulonephritis with λ light chain and C3c deposition and inflammatory cell infiltration with CD68. Macrophage lysosomes contained λ light chains, suggesting their partial phagocytosis. She was diagnosed with symptomatic MM and was treated with bortezomib and dexamethasone and an autologous peripheral stem cell transplant conditioned with intravenous melphalan. She achieved a partial response with decreased serum monoclonal protein and improved renal function. This case may be categorized as a monoclonal gammopathy‐associated proliferative glomerulonephritis. The biopsy finding of partially phagocytosed Ig λ light chains by macrophages is very rare; this pathological condition is similar to crystal‐storing histiocytosis.  相似文献   
125.
Although hematopoietic stem cell transplantation (HSCT) may increase the curability of refractory hematologic diseases, it requires complication management due to a long-term immunocompromised state. We experienced a case who received an autologous peripheral blood stem cell transplantation (Auto-PBSCT) for POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) and developed cutaneous Mycobacterium chelonae infection. It is clear that attention needs to be paid to prevent bacterial, fungal and viral infection after HSCT. It is also important to keep in mind that tuberculous and nontuberculous mycobacteria (NTM), in rare cases, lead to lethal complications.  相似文献   
126.

Purpose

Ultra-high resolution single-photon emission computed tomography (SPECT) system, using multiple pinhole collimators, has been applied to the imaging of small rodents. We aimed to compare the myocardial infarction (MI) area on quantitative perfusion single-photon emission computed tomography (QPS; Cedars-Sinai Medical Center, USA) with that on high-resolution autoradiography in rat model to determine the accuracy of perfusion defect measurement by QPS.

Procedures

After thoracotomy, rats (n?=?9) had their left coronary arteries occluded and reperfused before injection with 185 MBq [99mTc] methoxyisobutylisonitrile ([99mTc]MIBI) for SPECT and autoradiography. Healthy rats (n?=?28) were similarly scanned to create a normal database on which to base QPS. The MI area on SPECT images was analysed automatically by QPS software. For the autoradiography images, regions of interest for MI were set at 1 mm intervals.

Results

In normal rats, [99mTc]MIBI accumulated throughout the left ventricles, and a polar map of ventricular perfusion showed the lowest and highest uptakes in the inferior (68 %?±?4 %) and anterior (92 %?±?5 %) walls, respectively. In the rat MI model, the percentage of polar map with reduced [99mTc]MIBI uptake correlated strongly with the percentage of left ventricle with MI on autoradiography (r2?=?0.90).

Conclusions

QPS can quantitatively evaluate MI severity on myocardial perfusion images in rats, with comparable results to autoradiography. This widely available software could promote the development of new techniques for analysing cardiac images in small animals.
  相似文献   
127.

Background

Finding ways to improve the cervical cancer screening rates among young women has been seen as a critical national health problem in many countries, including Japan. The aim of the present study was to evaluate the effects of a free-coupon program for cervical cancer screening conducted by a local government under financial support from the Japanese national government.

Methods

The personal cervical cancer screening information was analyzed for all female residents of Toyonaka City, including any past screening history and clinical results since the year 2009, when a free-coupon program for screening was started. These results were compared to results from 2008, prior to implementation of the free-coupon screening program.

Results

The screening rates of women eligible for the free-coupon peaked dramatically compared to women of similar age who paid for their screening; however, the rates for the ineligible-age population also increased significantly in parallel to those in the free-coupon program, possibly by indirect peer and publicity effects. In women aged 20 to 25 years, the consecutive screening rate after a free-coupon screening was significantly lower than for those women who received a regular residential screening. After a free-coupon screening, the rate for participating in consecutive screenings depended significantly on the institution where the participant received her first screening test.

Conclusions

These results suggest that, for a generation of young women 20–25 years of age, a free-coupon program for cervical cancer screening was effective in increasing the first-time participation rate for screening; however, the increase in first-time participation did not lead to the expected increase in consecutive screenings.Key words: cervical cancer screening, free-coupon, screening rate, consecutive screening  相似文献   
128.
129.
130.
Interfacial interactions governing the interfacial adhesion between cellulose propionate and carbon fibre surface are placed under scrutiny to pave the way towards the development of green cellulose-based carbon fibre reinforced polymers. A range of molecular entities are deposited on the surface by initially grafting aromatic structures with appropriate functions via diazonium species followed by further derivatization of these entities. Cellulose propionate was also bound covalently to the surface via a tosylated derivative invoking its facile nucleophilic displacement reaction with surface-grafted amino functions. Significant increase in interfacial shear strength was obtained for the cellulose propionate-grafted carbon fibre composite as well as for the 4-(aminomethyl)benzene-functionalized sample, in the latter case possible hydrogen bonding took place with the cellulose propionate matrix. Furthermore, the positive effect of a highly lipophilic and yet compact –CF3 substituent was also noted. In order to let the grafted structure efficiently penetrate into the matrix, steric factors, lipophilicity and potential secondary interactions should be considered. It needs to be pointed out that we provide the first synthetic strategy to covalently bind cellulose derivatives to a largely graphitic surface and as such, it has relevance to carbonaceous materials being applied in cellulose-based innovative materials in the future.

Interfacial adhesion of a cellulose propionate/carbon fibre composite is tailored providing a synthetic strategy to bind cellulose derivatives to graphitic surfaces.  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