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   15220篇
  免费   745篇
  国内免费   54篇
耳鼻咽喉   254篇
儿科学   299篇
妇产科学   135篇
基础医学   1798篇
口腔科学   428篇
临床医学   880篇
内科学   3874篇
皮肤病学   482篇
神经病学   1002篇
特种医学   699篇
外科学   2776篇
综合类   62篇
一般理论   3篇
预防医学   383篇
眼科学   147篇
药学   919篇
中国医学   18篇
肿瘤学   1860篇
  2023年   72篇
  2022年   146篇
  2021年   262篇
  2020年   164篇
  2019年   217篇
  2018年   253篇
  2017年   198篇
  2016年   228篇
  2015年   222篇
  2014年   301篇
  2013年   391篇
  2012年   692篇
  2011年   722篇
  2010年   426篇
  2009年   402篇
  2008年   670篇
  2007年   735篇
  2006年   698篇
  2005年   713篇
  2004年   674篇
  2003年   701篇
  2002年   631篇
  2001年   583篇
  2000年   566篇
  1999年   499篇
  1998年   172篇
  1997年   178篇
  1996年   159篇
  1995年   132篇
  1994年   122篇
  1993年   109篇
  1992年   367篇
  1991年   347篇
  1990年   320篇
  1989年   329篇
  1988年   292篇
  1987年   301篇
  1986年   272篇
  1985年   293篇
  1984年   174篇
  1983年   157篇
  1982年   76篇
  1981年   65篇
  1979年   137篇
  1978年   70篇
  1975年   63篇
  1974年   72篇
  1973年   83篇
  1972年   63篇
  1971年   59篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Diastemstomyelia is an extremely rare disorder that is seldom found among the Japanese. This paper presents two Japanese patients, a newborn male and a newborn female, with diastematomyelia. CT demonstrated bony spurs more clearly than plain film, and magnetic resonance images indicated split cords and associated anomalies. Although the embryogenesis of diastematomyelia has not been clearly elucidated, the coincidence of levels of associated anomalies and diastematomyelia in our cases and in the literature supports Bremer's embryogenetic explanation of persistent accessory neurenteric canal.  相似文献   
62.
A phase I study of a recombinant gamma interferon (S-6810) was conducted in a cooperative study involving 11 institutions. S-6810 was administered at doses of 2, 4, 8, 12, 32 and 64 X 10(6) U/m2 by one-hour infusion for 5 consecutive days. A total of 40 courses were administered to 31 patients. High fever exceeding 38 degrees C with chills occurred in about 80% of patients. The incidences of other toxicities were fatigue in 50%, gastrointestinal toxicities in 30-40%, and changes in hepatic enzymes and hematologic toxicities in 20-30%. Dose-limiting factors were judged to be hypotension, leukopenia and central nervous toxicity. Maximum tolerated dose was 64 X 10(6) U/m2 and an optimal dose for phase II study was considered to be 6 X 10(6) U/m2 by daily chronic schedule. Blood concentration was highest at the end of infusion, and then decreased rapidly with a biphasic curve. The peak concentrations were elevated by escalation of doses. A partial response was observed in a patient with mycosis fungoides.  相似文献   
63.
The aims of the present study were to observe the daily habituation to night sleep in a laboratory environment and to make clear the daily and individual sleep variations by using polygraph parameters, including electroencephalography (EEG). Sleep EEG records were obtained from a subject who slept ten successive nights, and from six subjects who each slept one night in the laboratory. The parameters used were as follows: sleep stage %, sleep latency (SL), REM latency (RL), number of stage shifts, subjective sleep, integral EMG, and slope (a) and intersect (b) of a regression equation used to estimate the sleep depth against sleep time. Stage WAKE and SL, slope (a), intersect (b) and the mean depth of sleep were found to become stable from the fifth night. Stage MT, the number of stage shifts, and integral EMG increased significantly from the fifth night and later, showing p less than 0.01, p less than 0.01, and p less than 0.05, respectively. Judging from these findings, the sleep habituation of the subject in the laboratory was completed within the first four nights. Coefficients of variation of sleep stage 2 and stage REM of the ten-nights' EEG were the lowest among all the sleep parameters examined. Almost all the parameters of day-to-day sleep of the subject who slept for ten successive nights in the laboratory showed smaller variations than those of the other six subjects. It may be concluded that the mist effect on sleep could be assessed more precisely by using an individual repeatedly than by using a group of subjects.  相似文献   
64.
S Yamada  Y Takai  Y Ogawa  Y Kakuto  K Sakamoto 《Cancer》1989,64(5):1026-1028
Radiotherapy was applied to 14 esophageal carcinomas with respiratory tract fistulas using various treatment regimens. Closure of the fistulas was observed in four cases after irradiation at a daily dose of 1.5 Gy. The period of closure was transient in two cases but long-term in the other two. One long-term closure case underwent low-dose rate telecobalt therapy (LDRT)(1 Gy per hour, 7 Gy per day; a total dose of 28 Gy) as a boost. His cancer has been well controlled and he is still alive without recurrence at 74 months after fistula formation.  相似文献   
65.
Our objective was to analyze problems in the perioperative management and long-term outcome of living donor liver transplantation (LDLT) for biliary atresia (BA). Many reports have described the effectiveness of liver transplantation (LT) for BA, particularly in pediatric cases, but little information is available regarding LT in adults (> or =16 years old). Between June 1990 and December 2004, 464 patients with BA underwent LDLT at Kyoto University Hospital, of whom 47 (10.1%) were older than 16 years. In this study, we compared the outcomes between adult (> or =16 years old) and pediatric (<16 years old) patients. The incidence of post-transplant intestinal perforation, intra-abdominal bleeding necessitating repeat laparotomy and biliary leakage was significantly higher (p < 0.0001, <0.001 and <0.001, respectively) in adults. Overall cumulative 1-, 5- and 10-year survival rates in pediatric patients were significantly higher (p < 0.005) than in adults. Two independent prognostic determinants of survival were identified: a MELD score over 20 and post-transplant complications requiring repeat laparotomy. Outcome of LDLT in adult BA patients was poorer than in pediatric patients. It seems likely that LT will be the radical treatment of choice for BA and that LDLT should be considered proactively at the earliest possible stage.  相似文献   
66.
Y Makino  S Ueda  M Ogawa  J Hori  M Ohto  M Wakashin  E Tanabe 《Ryūmachi》1992,32(4):340-5; discussion 345-6
Sweet's syndrome (acute febrile neutrophilic dermatosis) is an unusual condition characterized by fever, polymorphonuclear neutrophil leukocytosis of the blood, thick painful plaques on the face, neck and limbs, and a dense dermal infiltrate of mature neutrophils seen histologically. Recently, this disease has also been reported in association with various malignant neoplasms and chronic inflammatory disorders. In the literature, seven cases of Sweet's syndrome associated with collagen diseases have been reported, but no cases with mixed connective tissue disease (MCTD). The first case of Sweet's syndrome associated with MCTD was herein described and discussed. A 49-year-old man was admitted to our hospital with the complaints of high fever and painful erythema on his face, neck and limbs. Six months ago, MCTD was suspected, with the presence of limited cutaneous sclerosis of the hands, Raynaud's phenomenon, polyarthralgia, an elevation of CPK value and a positive anti-RNP antibody. Just before hospitalization, he suffered a prodromal infection of the upper respiratory tract for two weeks. He was diagnosed as Sweet's syndrome by the clinical and histological features. He began receiving corticosteroid therapy (prednisolone 60 mg/day), and within a week he showed dramatic improvement in the above symptoms.  相似文献   
67.
It is known that a high concentration of iron is deposited in the enameloid of some teleostean fish. Previously, Suga et al. (1989) pointed out that the iron concentration in the enameloid is related to the phylogeny of fish rather than to the feeding habits, according to the results of quantitative iron analyses on the teeth of marine teleost fish of the Tetraodontiformes. In the present study, in order for the previous idea to be verified, quantitative iron analysis was made with an electron microprobe on the enameloid of fish belonging to the Perciformes, which is the largest group of teleostean fish in the world and consists of both marine and freshwater species. The enameloid of all the fish examined (57 species) contained high iron concentrations ranging from 0.2% to 10.2% at the surface or middle layer, whereas that of an advanced suborder, Tetraodontoidei, of the Tetraodontiformes was very low in iron, at a level which could not be discriminated from the background value of the emission intensity. The distribution pattern of iron in the enameloid was classified into at least two types, namely, type A, in which a high iron concentration was observed mainly in the surface layer, and type B, in which iron was deposited throughout the entire layer, although there were differences in concentration. There were some differences in the concentration and distribution of iron in the enameloid for the families; for example, those of the Scaridae had a type A distribution, with about 0.2% iron only at the surface layer, whereas those of the Cichlidae, Centrarchidae, and Acanthuridae, which showed a type B distribution, contained iron ranging from 2.9% to 10.5% at the surface or middle layer of enameloid. Such differences seemed to be associated with the difference in timing of the commencement of the iron deposition into the developing enameloid, which is probably related to the phylogeny of fish. There was no evidence to support the idea that the iron concentration in the enameloid is associated with the feeding habits of fish, as proposed by previous investigators.  相似文献   
68.
The study of intratumoral PO2 in brain tumors   总被引:1,自引:0,他引:1  
The aim of this study was to evaluate the hypoxic cells in the human brain tumor in vivo. Untreated 16 cases of brain tumor were analysed. During the surgery for the purpose of removal of the tumor, needle type-O2 sensors were inserted into femoral artery and in brain tumor to measure PaO2 and intratumoral O2 pressure. A plate type O2 sensor was put on the surface of surrounding brain cortex to measure cortical O2 pressure. These O2 sensors for this study is able to measure O2 pressure continuously and to observe these three O2 pressure simultaneously. Operations were performed endotracheal anesthesia under inhalation of ethrane with maintaining systolic blood pressure 120 mmHg. Setting the rate of O2 and N2O gas inhalation 1/3, PaO2 revealed about 110 mmHg which is similar value as physiological state--1 ATM, air inhalation--. The value of TuO2 and BrO2 were revealed 15.3 +/- 2.3 (mean +/- SE) mmHg and 59.8 +/- 6.5 (mean +/- SE) mmHg. According to these results, it might be said that hypoxic fraction surely exist intratumoral tissue. It is also well known that O2 removes from higher pressure zone to lower pressure zone after O2 was diffused from red blood cell in brain tissue. It might be also mentioned that much lower hypoxic fraction than the value of this study is existing intratumoral tissue. It has long been recognized that hypoxia influences the response of cells and tissues to radiation. However, they have been suspected on the basis of experimental data in vitro. This study showed hypoxic fraction in human brain tumor tissue in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
69.
Dilated cardiomyopathy (DCM) is characterized by progressive left ventricular (LV) systolic dysfunction of nonspecific etiology. Fifty-nine DCM patients were serially observed by echocardiography for 4.5 +/- 2.6 years, and 7.3 +/- 3.4 times M-mode and two-dimensional echocardiography was performed during the observation period using SSH-11A (Toshiba). To assess LV systolic function, ejection fraction was calculated by Pombo's method. Myocardial gray level distribution shown by echocardiography was calculated to assess the myocardial tissue character. Two-dimensional echocardiographic images were obtained in the parasternal short-axis view, recorded on U-matic videotape, and transferred to an image processing computer system (MIPRON, Kontron). The images were digitized and stored on the computer. The regions of interest (ROI) were placed in the LV septum, posterior papillary muscle, posterior wall, anterior papillary muscle and entire LV wall. The gray level distributions in each ROI and its quantitative parameters (mean, SD, skewness, excess) were calculated. The corrected myocardial gray level of every ROI (CMD) was also calculated and expressed as the ratio to the mean gray level of the LV cavity. Seven patients exhibited significant decreases in ejection fraction (more than 10%) during the observation period (group A); the remainders showed less change (group B).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
70.
In a model of dyskinesia induced by the administration of iminodipropionitrile (IDPN) in the rat, we evaluated the effects of ceruletide, an analogue of cholecystokinin, on behavioral abnormalities and monoaminergic neuronal function. Vertical head twitching in the IDPN-treated animals was inhibited for over 5 h following a single subcutaneous dose of 160 micrograms/kg ceruletide. In animals dosed daily for 2 or 3 days, the number of head twitches at 24 h after the last dose was about one-third of the number before treatment. After repeated daily doses of ceruletide for 6 days, the number of head twitches was reduced to low levels and remained significantly below pretreatment levels until the 4th posttreatment day. These results indicate that the inhibition of dyskinesia by ceruletide was long-lasting. Assays of monoaminergic neurotransmitters and their metabolites in various brain regions indicate that an imbalance between dopaminergic and serotonergic neuronal systems plays a major role in the pathogenesis of the IDPN-induced dyskinesia, i.e. the ratio of (DOPAC+HVA)/5-HIAA was significantly greater in the striatum but significantly smaller in the hippocampus of the IDPN-treated vs normal animals. This initially abnormal ratio of (DOPAC+HVA)/5-HIAA in the striatum and hippocampus of IDPN-treated animals returned to normal following treatment with ceruletide, corresponding with the reduction of the head twitching. The alterations in monoaminergic neuronal function induced by repeated administration of ceruletide persisted for at least 3 days, even though its plasma half-life is several minutes. Ceruletide also exerted a marked effect on monoaminergic neuronal function in the IDPN-treated rats, in contrast to only a slight effect in normal animals.(ABSTRACT TRUNCATED AT 250 WORDS)  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