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   8003篇
  免费   355篇
  国内免费   57篇
耳鼻咽喉   147篇
儿科学   182篇
妇产科学   59篇
基础医学   1028篇
口腔科学   199篇
临床医学   578篇
内科学   2022篇
皮肤病学   121篇
神经病学   592篇
特种医学   215篇
外科学   1412篇
综合类   34篇
预防医学   246篇
眼科学   103篇
药学   554篇
中国医学   27篇
肿瘤学   896篇
  2023年   53篇
  2022年   105篇
  2021年   201篇
  2020年   95篇
  2019年   132篇
  2018年   153篇
  2017年   133篇
  2016年   208篇
  2015年   163篇
  2014年   221篇
  2013年   297篇
  2012年   474篇
  2011年   527篇
  2010年   332篇
  2009年   289篇
  2008年   464篇
  2007年   552篇
  2006年   568篇
  2005年   628篇
  2004年   573篇
  2003年   479篇
  2002年   470篇
  2001年   79篇
  2000年   108篇
  1999年   123篇
  1998年   137篇
  1997年   129篇
  1996年   83篇
  1995年   72篇
  1994年   65篇
  1993年   48篇
  1992年   43篇
  1991年   58篇
  1990年   32篇
  1989年   33篇
  1988年   34篇
  1987年   36篇
  1986年   28篇
  1985年   31篇
  1984年   15篇
  1983年   13篇
  1982年   14篇
  1981年   16篇
  1980年   16篇
  1979年   16篇
  1978年   15篇
  1977年   17篇
  1975年   8篇
  1974年   6篇
  1969年   5篇
排序方式: 共有8415条查询结果,搜索用时 0 毫秒
101.
Quercetin is a promising food component, which can prevent lifestyle related diseases. To understand the dietary intake of quercetin in the subjects of a population-based cohort study and in the Japanese population, we first determined the quercetin content in foods available in the market during June and July in or near a town in Hokkaido, Japan. Red leaf lettuce, asparagus, and onions contained high amounts of quercetin derivatives. We then estimated the daily quercetin intake by 570 residents aged 20–92 years old in the town using a food frequency questionnaire (FFQ). The average and median quercetin intakes were 16.2 and 15.5 mg day−1, respectively. The quercetin intakes by men were lower than those by women; the quercetin intakes showed a low correlation with age in both men and women. The estimated quercetin intake was similar during summer and winter. Quercetin was mainly ingested from onions and green tea, both in summer and in winter. Vegetables, such as asparagus, green pepper, tomatoes, and red leaf lettuce, were good sources of quercetin in summer. Our results will help to elucidate the association between quercetin intake and risks of lifestyle-related diseases by further prospective cohort study and establish healthy dietary requirements with the consumption of more physiologically useful components from foods.  相似文献   
102.
Objective Classic Hodgkin lymphoma (CHL) has been regarded as a curable disease when treated appropriately, especially in younger patients, and ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) has been regarded as the standard regimen. However, a relatively poor prognosis has been reported in older patients with CHL, and the efficacy and tolerability of the ABVD regimen has not been fully elucidated. We retrospectively investigated the outcomes in patients with CHL treated with ABVD at our institute. Methods Twenty-five patients were evaluated; 14 were ≤60 years of age, and 11 were >60 years of age (older group). Results The ABVD doses were reduced in all patients in the older group; the median average relative dose intensity was 0.58. In the older group, the 5-year overall survival (OS) and median OS were 100% and not reached, respectively, for patients with early-stage CHL and 66.7% and not reached, respectively, for those with advanced-stage CHL. No patients died of CHL, and only one treatment-related death was observed in the older group. Conclusion ABVD with dose attenuation may represent a feasible and effective strategy for the treatment of older patients with CHL in clinical practice, particularly in those with early-stage disease, although the optimal degree of attenuation remains unclear.  相似文献   
103.
Both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) play a crucial role in elucidating the pathophysiology of coronary artery disease (CAD) with the goal to improve patient outcomes of medical and/or interventional CAD management. However, no single intravascular imaging technique has been proven to provide complete and detailed evaluation of all CAD lesions due to some limitations. Although sequential use of multiple modalities may sometimes be performed, there may be issues related to risk, time, and cost. To overcome these problems, several hybrids involving dual-probe combined IVUS-OCT catheters have been developed.The aim of this review article is to demonstrate some limitations of stand-alone imaging devices for evaluation of CAD, summarize the advances in hybrid IVUS-OCT imaging devices, discuss the technical challenges, and present the potential value in the clinical setting, especially in patients receiving medical or interventional CAD management.  相似文献   
104.
Journal of Gastroenterology - The development of feasible, reliable parameters and criteria for intestinal ultrasound (IUS) to estimate endoscopic remission of ulcerative colitis (UC) is a crucial...  相似文献   
105.
The prevalence of immunity against diphtheria among Okayama local government staff members involved in diphtheria infection control was measured. Diphtheria booster vaccination was administered to staff members with low antitoxin levels (<0.1 IU/ml) in order to reinforce of immunity. Ninety-one (36.7%) of 248 staff members, 20-69 years of age, had fully protective antitoxin levels (> or =0.1 IU/ml), and the remaining 157 (63.3%) showed levels of <0.1 IU/ml. The rate of full protection was higher in females (44.9%) than in males (22.8%) and was also higher in the diphtheria-pertussis mixed vaccine (born in 1958-1967) and diphtheria-pertussis-tetanus mixed vaccine (born in 1968-) (58.3-61.0%) groups than in diphtheria vaccine (born in 1948-1957) and non-vaccinated (born until 1947) (7.4-18.9%) groups. Though antitoxin levels of 13 (68.4%) out of 19 staff members given booster vaccinations increased to 0.1 IU/ml, 50% of these individuals then showed levels of <0.1 IU/ml after 3 years. Most of the staff members with antitoxin levels of > or =0.1 IU/ml in the non-booster vaccination group maintained their immunity levels for 2-4 years, independent of their history of vaccination. To ensure that staff members of the local government have fully protective antitoxin levels against diphtheria, periodical confirmation of antitoxin levels and booster vaccination should both be systematically carried out.  相似文献   
106.
Glaucoma is defined as an optic neuropathy with characteristic changes in the optic nerve head and ultimate loss of visual field. Previous studies have suggested that (a) mechanical damage due to raised intraocular pressure and (b) a compromised tissue circulation in the optic nerve head play significant roles in the development of glaucomatous damage in the optic nerve head. Recently, we found that lomerizine, a new Ca2+ channel blocker, increased ocular circulation and protected neuronal cells against retinal neurotoxicity both in vitro and in vivo with minimal cardiovascular side effects. We examined the effect of lomerizine on the ocular circulation and compared it with those of other Ca2+ channel blockers in normal rabbits and in rabbits with an endothelin‐1‐disturbed circulation in the optic nerve head. In anesthetized rabbits, lomerizine and the other Ca2+ channel blockers increased the ocular circulation and also inhibited the hypoperfusion induced in optic nerve head tissue by an intravitreous injection of endothelin‐1. Whereas the other Ca2+ channel blockers produced changes in blood pressure and heart rate, the effects of lomerizine on these parameters were slight. In healthy humans, lomerizine increased blood velocity in the optic nerve head, without significantly altering blood pressure or heart rate. Moreover, lomerizine reduced retinal damage in rats both in vitro and in vivo, presumably through a Ca2+ channel blocking effect via an action that may involve a direct protection of retinal neurons as well as an improvement in the ocular circulation. These results indicate that lomerizine may be useful as a therapeutic drug against ischemic retinal diseases (such as glaucoma and retinal vascular occlusive diseases) that involve a disturbance of the ocular circulation.  相似文献   
107.
We report a case of multiple cavernous hemangioma of the small intestine which was diagnosed definitively before operation. A 33-yr-old male was found to have multiple polypoid lesions in the small intestine during examination for recurrent iron deficiency anemia. Plain X-ray film of the abdomen revealed multiple calcifications in the middle to lower region, suggestive of cavernous hemangioma, which was further confirmed by angiography and scintigraphy with Tc 99m-labeled red blood cells. Endoscopy during surgery was used to determine the extent of surgical resection. Seventy-three cases of hemangioma of the small intestine were reported in Japan between 1953 and 1988 and their clinical features were reviewed.  相似文献   
108.
109.

Background

The Ras-like GTPases, RalA and RalB are members of the Ras superfamily of small GTPases. Aberrant activation of Ral is a major cause of human tumorigenesis induced by oncogenic Ras. Serum anti-RalA antibodies are induced in esophageal carcinoma patients. However, detailed comparisons of their pathological characteristics are unavailable, and conventional serum markers have not been well evaluated.

Methods

Serum samples of 171 patients with esophageal squamous cell carcinoma and 73 healthy individuals were analyzed using specifically developed ELISA system for serum anti-RalA antibodies. A cut-off optical density value was fixed at 0.255 (the control mean + 2 SD). Clinicopathological characteristics and positive rates of conventional tumor markers were evaluated for seropositive patients.

Results

Overall positive rate for serum anti-RalA antibodies was 18 %, which gradually increased with the tumor stages. Although the positive rate for serum anti-RalA antibodies was comparable with that of carcinoembryonic antigen (24 %) and CYFRA21-1 (21 %), it was lower than the rate for serum p53 antibodies (31 %) and squamous cell carcinoma antigen (37 %). Although serum anti-RalA antibodies were not associated with other serum markers, it was inversely associated with serum p53 antibodies. No clear association was observed between serum anti-RalA antibodies and RalA immunoreactivity.

Conclusions

Presence of serum anti-RalA antibodies is associated with tumor stages, but not with conventional tumor markers. Serum anti-RalA antibodies may be candidate serum markers in combination with other serum markers for esophageal squamous cell carcinoma.
  相似文献   
110.
Thrombopoietin stimulated blast colony formation in 11/20 acute myelogenous leukaemia (AML) patients studied. The FAB subtypes of the blasts responding to thrombopoietin were not restricted to those of the megakaryocyte lineage, but also included M1–M5 AML blasts. The morphology of colony cells produced by megakaryocytic blasts showed megakaryocytoid features, whereas colony cells produced by M1–M5 AML blasts remained myeloblasts. An increase in CD41 was observed in the cells of colonies produced by blasts from the megakaryocyte lineage involving leukaemia and chronic myeloid leukaemia in blastic crisis. Thrombopoietin receptor was observed on leukaemic blasts which formed colonies following incubation with thrombopoietin.  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