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   38514篇
  免费   2174篇
  国内免费   379篇
耳鼻咽喉   654篇
儿科学   398篇
妇产科学   518篇
基础医学   6296篇
口腔科学   981篇
临床医学   3046篇
内科学   7530篇
皮肤病学   1509篇
神经病学   2695篇
特种医学   2573篇
外国民族医学   1篇
外科学   4720篇
综合类   191篇
一般理论   7篇
预防医学   1795篇
眼科学   716篇
药学   3905篇
中国医学   510篇
肿瘤学   3022篇
  2024年   25篇
  2023年   263篇
  2022年   856篇
  2021年   1355篇
  2020年   623篇
  2019年   886篇
  2018年   1112篇
  2017年   909篇
  2016年   1305篇
  2015年   1744篇
  2014年   2064篇
  2013年   2347篇
  2012年   3549篇
  2011年   3456篇
  2010年   2027篇
  2009年   1750篇
  2008年   2439篇
  2007年   2208篇
  2006年   1981篇
  2005年   1835篇
  2004年   1428篇
  2003年   1244篇
  2002年   1076篇
  2001年   833篇
  2000年   790篇
  1999年   561篇
  1998年   237篇
  1997年   149篇
  1996年   131篇
  1995年   90篇
  1994年   106篇
  1993年   89篇
  1992年   155篇
  1991年   168篇
  1990年   183篇
  1989年   152篇
  1988年   132篇
  1987年   127篇
  1986年   106篇
  1985年   84篇
  1984年   57篇
  1983年   50篇
  1982年   31篇
  1981年   45篇
  1979年   33篇
  1978年   27篇
  1977年   31篇
  1975年   24篇
  1971年   26篇
  1970年   28篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Concentrations of metabolites and immunoreactive insulin (IRI) and activities of enzymes related to energy metabolism were measured in plasma of Korean and Japanese beef cattle, which were raised by the indoor feeding system programmed to feed larger amount of roughage in their growing periods and larger amount of concentrate diet in their finishing periods (Japanese feeding system), and grazing New Zealand beef cattle. By the Japanese beef grading system, Korean and Japanese beef cattle showed high beef quality score, average grade 3.3 and 3.6, respectively. The plasma free fatty acid and lactate concentrations and lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AST) activities in Korean beef cattle were significantly higher than those in Japanese beef cattle. The plasma lactate concentration in Korean beef cattle was 8.40 mmol/l, which was similar to the values observed in lactic acidosis. The higher activities of plasma LDH, MDH and AST may indicate slight liver damage by slightly acidotic conditions in Korean beef cattle. New Zealand beef cattle fed on pasture which they harvest by grazing showed significantly lower plasma glucose, cholesterol, lactate and IRI concentrations and enzyme activities than those in Korean and Japanese beef cattle fed on larger amount of concentrate diets. Plasma metabolite concentrations and energy metabolism‐related enzyme activities may be good indicators for evaluating metabolic conditions of beef cattle raised by different feeding systems.  相似文献   
62.
63.
To identify tobacco recidivism among 86 heart transplant recipients who were smokers but demonstrated compliance with a smoking cessation program pre-transplant, we used a questionnaire and randomly tested urine for nicotine and its by-products. In 36 patients, we also evaluated circulating levels of HS-CRP, homocysteine and MPV. Twenty-eight (32.5%) of 86 patients met our definition for tobacco exposure. In this cohort, 28 (32.5%) of 86 patients met our definition for tobacco exposure. Of these 28, 12 patients self-reported tobacco use and demonstrated biochemical verification; 14 patients demonstrated only biochemical evidence of significant tobacco exposure; 2 patients self-reported tobacco use but did not demonstrate biochemical positivity. Smoking cessation within 6 months of transplantation (r = 0.52) and time post-transplantation (r = 0.43) were independent predictors for recidivism of tobacco use, p < 0.01. No differences in HS-CRP, homocysteine and MPV levels were noted among the groups. Our investigation demonstrates a high rate of tobacco recidivism among heart transplant recipients, yet few admit to it. The adverse effects of tobacco do not appear to be directly modulated by an effect on athero-thrombotic risk markers.  相似文献   
64.
We report here our 10-year experience of a biopsy performed at day 14 after transplantation in 304 patients with stable graft function. The factors that may have influenced subclinical rejection were analyzed according to histology. The incidence of subclinical rejection was 13.2%. Addition of mycophenolate mofetile (MMF) as a primary immunosuppressant significantly decreased the incidence of subclinical rejection compared with patients without such treatment (odds ratio, 0.23; p < 0.05). On the other hand, HLA-DR antigen mismatch (odds ratio, 2.39) and unrelated donor (odds ratio, 2.10) were also significantly associated with decreased subclinical rejection (p < 0.05). The incidence of acute rejection in patients with normal findings was lower than in those with borderline changes or subclinical rejection (0.23 +/- 0.05 vs. 0.48 +/- 0.07 and 0.60 +/- 0.11, respectively; p < 0.05). The graft survival rates in patients with subclinical rejection were lower than in patients with normal or borderline changes at 1 (88.4% vs. 97.9% and 99.1%; p < 0.05), 5 (77.8% vs. 96.2% and 95.9%; p < 0.05) and 10 (62.3% vs. 96.2% and 93.7%; p < 0.05) years. Thus, a protocol biopsy performed on day 14 after transplantation is useful for predicting graft survival. Triple therapy including MMF, related donor and HLA-DR antigen match are important factors for reducing subclinical rejection in living-donor renal transplantation.  相似文献   
65.
The Stiles-Crawford effect of the first kind (SCE-I) was measured on both emmetropic and myopic subjects at six different retinal locations. The results revealed a number of significant discrepancies in receptor alignment between the groups of different refractive errors. In myopic subjects, the receptors in the nasal retina (i.e. between the fovea and the optic nerve head) were found to be aligned nasally towards the optic nerve head, whereas the receptors in the temporal retina were aligned towards the centre of the exit pupil. In emmetropic subjects, the receptors across the retina were finely tuned towards the centre of the exit pupil. The magnitude of the receptor displacement in myopic subjects was found to be directly associated with the length of the eyeball.  相似文献   
66.
OBJECTIVE: Behavioral disturbances in dementia are extremely prominent and distressful, and often result in serious physical, social, and economic consequences. The authors compared the efficacy and tolerability of risperidone and haloperidol in the treatment of behavioral and psychological symptoms of dementia (BPSD) in institutionalized elderly Korean patients with Alzheimer disease, vascular dementia, or mixed dementia. METHODS: This was an 18-week double-blind, crossover study involving 120 patients who were randomly assigned to receive flexible doses (0.5-1.5 mg/day) of risperidone or haloperidol. BPSD were assessed using the Korean version of the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD-K), the Korean version of the Cohen-Mansfield Agitation Inventory (CMAI-K), and the Clinical Global Impression of Change scale (CGI-C). Safety and tolerability assessments included the Extrapyramidal Symptom Rating Scale and the incidence of adverse events. RESULTS: Both risperidone and haloperidol were efficacious in alleviating BPSD. However, when receiving risperidone, patients showed significantly greater improvement than when receiving haloperidol in the total and subscale scores of the BEHAVE-AD-K, the total and subscale scores of the CMAI-K, and the scores on the CGI-C scale. Also, risperidone had an additional benefit on aggressiveness and anxieties/phobias. The risk of antipsychotic-induced parkinsonism throughout this study was significantly lower with risperidone than with haloperidol. CONCLUSION: Risperidone had a favorable efficacy and tolerability profile compared with haloperidol in the treatment of BPSD in this patient population.  相似文献   
67.
BACKGROUND: IgE-mediated carboplatin hypersensitivity reactions occur in up to 30% of patients receiving this agent for chemotherapy of solid tumors, thus limiting therapeutic options. OBJECTIVE: To describe our experience with intravenous carboplatin desensitization regimens, which culminated in a standardized, successful protocol for safe administration. METHODS: Eight consecutive patients with ovarian cancer who had experienced severe anaphylactic reactions to carboplatin were referred to our hospital. Intradermal skin testing was performed by raising a 3-mm bleb by injection of undiluted carboplatin at 10 mg/mL, and the wheal size was read at 20 minutes. The outcomes of the various desensitization regimens were documented prospectively, and the experience gained was used to develop a standardized protocol for administration. RESULTS: All patients had positive intradermal skin test results. The first 3 patients were treated with short (90 minutes to 6 hours) desensitization protocols, and all protocols failed on the first or second infusions. These 3 and a subsequent 5 patients were given intravenous carboplatin according to a protocol of gradual dose escalation over a 4-log dose range given during a 4-day period, with subsequent 3-weekly infusions given more rapidly by omitting the most dilute log dose on each occasion. All patients tolerated the longer infusion protocol without event, and all but 1 patient experienced appropriate tumor marker response. CONCLUSIONS: Short carboplatin desensitization protocols (less than 6 hours) have an unacceptable failure rate in patients with carboplatin allergy, but longer infusion times (days) are well tolerated without recurrence of the allergic reaction and with good tumor response. In cases where carboplatin is the optimal therapeutic agent, clinicians should not be deterred by an anaphylactic reaction to it or by failure of shorter desensitization regimens.  相似文献   
68.
The success of modern burn therapy is based mainly on special burn intensive care, topical treatment, early eschar excision, and wound closure by immediate skin grafting or skin substitutes. This paper describes the current state of wound care and skin substitutes in burn therapy.  相似文献   
69.
目的:探讨抗青光眼餐引流术后的白内障患眼进行超声乳化吸除术的手术入路,操作方式及临床效果。方法:避开功能性滤过泡,选择角巩膜隧道切口或透明角膜切口,瞳孔麻痹性散大时,做一个完美的直径约5mm的连续环形撕囊以补偿之;恰当处理虹膜后粘连后,在病理性小瞳孔下完成超声乳化手术;眼压失控者行青光眼白内障人工晶体植入三联术。结果:无后囊破裂,人工晶体全部囊袋内植入,术后1周视力≥0.5者20只眼(64.5%),0.1-0.4者8只眼(25.8%),<0.1者3只眼(9.7%)。随访1-16个月,眼压均在20.55mmHg以下。结论:体外流术后的白内障患眼,超声乳化手术因其切口小,并发症少,不破坏功能性滤过泡,不损伤瞳孔,是目前各种手术方法中的最佳选择。  相似文献   
70.
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