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   14903篇
  免费   930篇
  国内免费   94篇
耳鼻咽喉   131篇
儿科学   318篇
妇产科学   875篇
基础医学   1894篇
口腔科学   310篇
临床医学   1681篇
内科学   3144篇
皮肤病学   276篇
神经病学   1142篇
特种医学   419篇
外科学   1990篇
综合类   279篇
一般理论   8篇
预防医学   792篇
眼科学   424篇
药学   1067篇
中国医学   126篇
肿瘤学   1051篇
  2023年   67篇
  2022年   198篇
  2021年   356篇
  2020年   155篇
  2019年   310篇
  2018年   413篇
  2017年   250篇
  2016年   280篇
  2015年   440篇
  2014年   534篇
  2013年   751篇
  2012年   1099篇
  2011年   1167篇
  2010年   743篇
  2009年   600篇
  2008年   863篇
  2007年   864篇
  2006年   827篇
  2005年   796篇
  2004年   724篇
  2003年   636篇
  2002年   608篇
  2001年   549篇
  2000年   526篇
  1999年   376篇
  1998年   108篇
  1997年   100篇
  1996年   91篇
  1995年   78篇
  1994年   66篇
  1993年   54篇
  1992年   181篇
  1991年   152篇
  1990年   116篇
  1989年   112篇
  1988年   105篇
  1987年   82篇
  1986年   71篇
  1985年   62篇
  1984年   46篇
  1983年   32篇
  1982年   25篇
  1981年   23篇
  1980年   18篇
  1979年   42篇
  1978年   24篇
  1977年   22篇
  1976年   20篇
  1975年   24篇
  1973年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Clinical and Experimental Nephrology - Page kidney is a rare condition leading to secondary hypertension and encountered most frequently due to traumatic subcapsular hematoma. Here, we present a...  相似文献   
62.
Two middle age sisters had most manifestations of the SC phocomelia syndrome including postnatal growth retardation, symmetric limb deficiencies with radial aplasia and absent thumbs, facial anomalies with microcephaly, microphthalmia, hypoplastic nasal alae, and borderline to mild mental retardation. Unusual findings included congenital paralysis of some cranial nerves in both patients and malignant melanoma in the proposita. Cultured lymphocytes from both patients, and skin fibroblasts, Epstein Barr virus-transformed lymphocytes, and tumor cells from the proposita demonstrated premature separation of centromeric heterochromatin (PCS) of many chromosomes, a finding noted previously in the SC phocomelia syndrome and the similar but more severe Roberts syndrome. Extensive overlap of the phenotypes of the sisters and 15 other patients with either syndrome and PCS confirms that these are either allelic conditions or the same disease--designated Roberts-SC phocomelia syndrome. The role of PCS in the syndrome(s) remains uncertain since some patients with the characteristic clinical phenotypes are reported to lack it.  相似文献   
63.
Hep3B and PLC/PRF/5 human hepatoma cells express epidermal growth factor (ECF) mRNA and secret this polypeptide growth factor into the culture medium. The production of EGF was inhibited by sodium butyrate in a dose-dependent manner. EGF receptor numbers in both cell lines were increased after treatment with butyrate for 2 days, In addition, the binding affinity of EGF to its receptor was decreased in butyrate-treated PLC/PRF/5 cells while it did not change in Hep3B cells. EGF-stimulated cell growth in PLC/PRF/5 cells was attenuated by sodium butyrate whereas no significant inhibition df cell growth of Hep3B cells was found in the same condition. Our results suggest that EGF acts as an autocrine growth stimulator in human hepatoma cells and sodium butyrate can differentially regulate the responses of hepatoma cells to EGF by modulating the differentiation states of these cells.  相似文献   
64.
The possible association between the risk of rectal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible rectal cancer deaths (986 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (986 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan were collected from Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair matched to the cases by sex, year of birth, and year of death. The results show a significant negative relationship between drinking water hardness and rectal cancer mortality. Odds ratio and 95% confidence intervals were 1.24 (1.01-1. 55) and 1.38 (1.10-1.73), respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Trend analyses showed an increasing odds ratio for rectal cancer with decreasing levels of hardness in drinking water. This is an important finding for the Taiwan water industry and human health.  相似文献   
65.
Fungal corneal ulcers related to agriculture has been reported throughout the world, especially in tropical areas. Most of them were sporadic and had histories of ocular trauma or use of topical corticosteroids and topical antibiotics. Five onion harvesters had fungal corneal ulcers during the same harvest period in Southern Taiwan. The authors think that this is the first report of a group occurrence relating to agricultural workers. Although all of the patients improved after medical and surgical management, their vision was greatly decreased. It is suggested that the tropical climate, the harvest procedure, the characteristic monsoon, and lack of eye protection were involved. Therefore, the importance of the eye protection, hygiene education, and improving medical care to reduce the occurrence of fungal corneal ulcer in agriculture workers must be emphasised.

 

  相似文献   
66.
Balloon angioplasty is a standard treatment for artherosclerotic coronary artery disease. However, its clinical value is reduced by a high restenosis rate. A new concept in preventing restenosis is the use of a liquid-filled balloon containing a beta-emitting radioisotope. In this study, we performed biodistribution studies of Re-188 perrhenate and Re-188 diethylenetriaminopentaacetate (DTPA) to assess the resulting organ dose values in the event of balloon rupture if these agents are used for the clinical inhibition of restenosis after percutaneous transluminal coronary angioplasty (PTCA). After injecting Re-188 preparations intravenously, rats were killed at 10 min, 30 min, 60 min, 2 h, and 6 h ( n =5 per group). Tissue concentrations were calculated and expressed as percent injected dose per gram or per milliliter (%ID/g or %ID/mL). In addition, urine excretion and thyroid gland uptake were evaluated in rats ( n=5 per group) with a gamma camera after administration of 37 MBq (1 mCi) of each agent. Our data showed that both agents were excreted primarily via urine. However, the excretion of Re-188 DTPA was much faster than that of Re-188 perrhenate via the urinary system. The biodistribution data revealed that radioactivity levels in the stomach and the thyroid gland were high in the perrhenate group but low in the Re-188 DTPA group. The concentration levels in other tissues including lung, liver, testis, muscle, and blood were low throughout this study for both agents. The thyroid radiation value in the Re-188 perrhenate group was 0.163 mGy/MBq, which was much higher than that of the Re-188 DTPA group (0.0167 mGy/MBq). The stomach radiation value was as high as 0.127 mGy/MBq for Re-188 perrhenate, compared with 0.013 mGy/MBq for Re-188 DTPA. In conclusion, in the event of balloon rupture, the release of Re-188 DTPA results in lower radiation doses than Re-188 perrhenate, especially to the thyroid gland and the stomach. Our data suggest that Re-188 DTPA is a useful radiopharmaceutical for endovascular irradiation.  相似文献   
67.
We investigated the association between schizophrenic psychosis and an intronic polymorphism of the presenilin-1 (PS1) gene in a Chinese population. Schizophrenic and control groups had similar PS1 genotype distributions and allele frequencies, indicating that this polymorphism may not be involved in the development of schizophrenia.  相似文献   
68.
PURPOSE: We examined the efficacy of potassium citrate based medical prophylaxis for preventing upper urinary calculous recurrence, and compared it with the stone recurrence rate in patients who only received intermittent or no medical prophylaxis. MATERIALS AND METHODS: We retrospectively reviewed the records of 493 patients with upper urinary calculi, of whom 237 men and 76 women with a mean age of 56.1 and 51.4 years, respectively, were enrolled in the study. Of the 313 participants 64 (group 1, 20.4%) received regular medical prophylaxis for 24 to 42 months (mean 27.8), 80 (group 2, 25.6%) received intermittent medical prophylaxis for 1.5 to 19 months (mean 7.9) and 169 (group 3, 54%) did not receive any medical prophylaxis. RESULTS: At midterm followup of 24 to 60 months 107 patients (34.2%) had stone recurrence. In group 1 the stone recurrence rate was 7.8%, which was significantly less (p <0.001) than in groups 2 (30%) and 3 (46.2%). Similarly new calculous events in patients with a history of multiple stone recurrence were less frequent in group 1 than in groups 2 and 3 (9.7, 47.4 and 52.2%, respectively, p <0.001). Multiple stone recurrence history, hypercalciuria, hyperuricosuria and calcium oxalate dihydrate calculi were independent risk factors for stone recurrence. CONCLUSIONS: Regular medical prophylaxis may effectively prevent stone recurrence regardless of previous treatment modalities, stone composition, metabolic abnormalities and stone-free status. Cost effectiveness, patient compliance and gastrointestinal upset may limit patient acceptability and clinical use of medical prophylaxis. However, patients with a history of multiple stone recurrence, calcium oxalate dihydrate stones, hypercalciuria and hyperuricosuria benefit from regular medical prophylaxis.  相似文献   
69.
From 1983 through 1993, 786 strains of Vibrio parahaemolyticus were collected from food-borne disease outbreaks and sporadic cases of diarrheal illness in northern Taiwan, involving 42 K-serotypes. Five top leading serotypes were K8 (36.8%), K15 (10.8%), K12 (8.7%), K56 (7.9%) and K63 (4.7%). However, a variation of K-serotypes was found during this study period. From 112 food-borne outbreaks associated with this microorganism, only 54 (48.2%) outbreaks were caused by a single serotype, while 58 (51.8%) were caused by multiple K-serotypes. Numbers of outbreaks caused by two, three and more than three K-serotypes were 29 (26%), 16 (14.2%), and 13 (11.6%), respectively. In a special outbreak, eight K-serotypes was found. Outbreaks caused by party caterers were most frequently associated with multiple K-serotypes.  相似文献   
70.
Conclusion The behavioral and/or psychiatric symptoms in autistic people as described above have been viewed by many professionals dealing with autistic populations as associated features of autism that may result from these individuals' inability to cope with the environmental demands and physical discomfort. Traditionally, in treating individuals with autism, special education intervention including behavioral modifications has been the main emphasis. Such an approach has made some progress in milder and uncomplicated cases of autism. However, if many of these behavioral and/or psychiatric symptoms in those with more severe associated features can be viewed as symptoms of various comorbid psychiatric disorders, there are data suggesting that with an appropriate evaluation, predrug workups, a specific diagnosis, and multiple measures of outcome, pharmacotherapy can be a safe and efficacious adjunct treatment for some symptoms in autistic persons. Nevertheless, the data presented here were obtained mainly from autistic children. A great deal of work remains to be done Future research should put more emphasis on developing agreeable, reliable, and valid diagnostic instruments for identifying comorbid psychiatric disorders in autistic people. Future research should also emphasize employing a randomized double-blind placebo-controlled crossover design, as well as involving multicenters and using uniformed diagnostic criteria to study autistic adolescents and adults.  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