全文获取类型
收费全文 | 17037篇 |
免费 | 1015篇 |
国内免费 | 123篇 |
专业分类
耳鼻咽喉 | 134篇 |
儿科学 | 413篇 |
妇产科学 | 894篇 |
基础医学 | 2312篇 |
口腔科学 | 387篇 |
临床医学 | 1926篇 |
内科学 | 3633篇 |
皮肤病学 | 388篇 |
神经病学 | 1179篇 |
特种医学 | 685篇 |
外科学 | 2153篇 |
综合类 | 327篇 |
一般理论 | 8篇 |
预防医学 | 865篇 |
眼科学 | 449篇 |
药学 | 1204篇 |
中国医学 | 127篇 |
肿瘤学 | 1091篇 |
出版年
2023年 | 69篇 |
2022年 | 199篇 |
2021年 | 365篇 |
2020年 | 158篇 |
2019年 | 315篇 |
2018年 | 430篇 |
2017年 | 263篇 |
2016年 | 298篇 |
2015年 | 464篇 |
2014年 | 553篇 |
2013年 | 823篇 |
2012年 | 1120篇 |
2011年 | 1178篇 |
2010年 | 786篇 |
2009年 | 630篇 |
2008年 | 884篇 |
2007年 | 905篇 |
2006年 | 871篇 |
2005年 | 819篇 |
2004年 | 742篇 |
2003年 | 659篇 |
2002年 | 625篇 |
2001年 | 578篇 |
2000年 | 548篇 |
1999年 | 409篇 |
1998年 | 190篇 |
1997年 | 195篇 |
1996年 | 195篇 |
1995年 | 148篇 |
1994年 | 138篇 |
1993年 | 130篇 |
1992年 | 220篇 |
1991年 | 188篇 |
1990年 | 157篇 |
1989年 | 178篇 |
1988年 | 162篇 |
1987年 | 130篇 |
1986年 | 122篇 |
1985年 | 100篇 |
1984年 | 101篇 |
1983年 | 59篇 |
1982年 | 56篇 |
1981年 | 60篇 |
1980年 | 67篇 |
1979年 | 65篇 |
1977年 | 57篇 |
1976年 | 58篇 |
1975年 | 60篇 |
1965年 | 52篇 |
1960年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
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
92.
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
93.
S. H. Lin C. P. Lin H. Z. Wang R. K. Tsai C. K. Ho 《Occupational and environmental medicine》1999,56(6):423-425
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
94.
Hsieh BT Hsieh JF Tsai SC Lin WY Huang HT Ting G Wang SJ 《Nuclear medicine and biology》1999,26(8):741-972
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
95.
Chiu HJ Tsai SJ Chen JY Lin CY Bai YM Song HL Lai HC Hong CJ 《Psychiatry research》1999,87(2-3):245-248
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
96.
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
97.
Wang TK Ho SI Tsai JL Pan TM 《Zhonghua Minguo wei sheng wu ji mian yi xue za zhi = Chinese journal of microbiology and immunology》1996,29(4):210-224
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
98.
Luke Y. Tsai 《Journal of autism and developmental disorders》1996,26(2):159-163
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
99.
SLIKKER WILLIAM JR; PAULE MERLE G.; ALI SYED F.; ANDREW C. SCALLET; BAILEY JOHN R. 《Toxicological sciences》1991,17(2):321-334
Chronic Marijuana Smoke Exposure in the Rhesus Monkey I. PlasmaCannabinoid and Blood Carbxyhemoglobin Concentrations and ClinicalChemistry Parameters SLIKKER, W., JR., PAULE, M. G., ALI, S.F., SCALLET, A. C., AND BAILEY, J. R (1991). Fundam. Appl Toxicol17, 321334. This report is the first in a series abouta large multidisciplinary study designed to determine whetherchronic marijuana (MJ) smoke exposure results in residual behavioraland/or neuropathological alterations in the rhesus monkey. Priorto the initiation of a year of chronic MJ smoke exposure, 64periadolescent male rhesus monkeys were trained for 1 year toperform five operant behavioral tasks and then divided, accordingto their performance in these tasks, into four exposure groups(n=1516/group): (1) a high dose (HI) group, exposed 7days/week to the smoke of one standard MJ cigarette; (2) a lowd m (LO) group, exposed on weekend days only to the smoke ofa standard MJ cigarate; (3) an extracted MJ cigarette (EX) group,exposed 7 days/week to the smoke of one ethanol-extracted MJcigarette; and (4) a sham group (SH), exposed 7 days/week tosham exposure conditions. Daily exposures for 1 year were accomplishedusing a mask that covered the subjects' nose and mouth. Averagebody weights (initially 3.7?0.5 kg, mean?SD) and rates of weightgain (approximately 0.1 kg/month) were the same for all groupsthroughout the entire experiment. During the first week of expsure,plasma concentrations of -9-tetrahydrocannabinol and 11-nor-9-carboxy-THCin the HI group were 59?7 (mean?SE) and 5.5?1.5 ng/ml, respectively,45 min after MJ smoke administration and did not change significantlyat similar times after exposure throughout the remainder ofthe year. Whole blood carboxyhemoglobin levels increased toapproximately 13% 1 min after expsure to smoke in either theMJ or the EX groups. Comparison of blood chemistry and hematologyvalues before, during, and after exposure indicated no differencesfor most parameters. During exposure, lymphocytes, alkalinephosphatase and -glutamyl transferase were depressed in theHI group compared to in the SH group. During exposure, aspartateaminotransferase was elevatd for both the HI and EX groups,suggesting a general effect of smoke exposure. Because theseeffects were transient and remained within the range of reportednormal values, these data indicate that long-term, experimentalexperimental exposure to MJ smoke is feasible and does not compromisethe general health of the rhesus monkey. 相似文献
100.