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   28880篇
  免费   1383篇
  国内免费   230篇
耳鼻咽喉   368篇
儿科学   619篇
妇产科学   324篇
基础医学   3539篇
口腔科学   483篇
临床医学   1720篇
内科学   8087篇
皮肤病学   489篇
神经病学   2328篇
特种医学   1060篇
外科学   5110篇
综合类   104篇
预防医学   742篇
眼科学   497篇
药学   1579篇
中国医学   48篇
肿瘤学   3396篇
  2023年   181篇
  2022年   425篇
  2021年   717篇
  2020年   369篇
  2019年   484篇
  2018年   689篇
  2017年   543篇
  2016年   614篇
  2015年   667篇
  2014年   845篇
  2013年   1030篇
  2012年   1618篇
  2011年   1876篇
  2010年   1104篇
  2009年   940篇
  2008年   1631篇
  2007年   1755篇
  2006年   1737篇
  2005年   1778篇
  2004年   1740篇
  2003年   1595篇
  2002年   1618篇
  2001年   548篇
  2000年   536篇
  1999年   504篇
  1998年   352篇
  1997年   299篇
  1996年   245篇
  1995年   221篇
  1994年   206篇
  1993年   188篇
  1992年   315篇
  1991年   305篇
  1990年   245篇
  1989年   300篇
  1988年   220篇
  1987年   214篇
  1986年   198篇
  1985年   180篇
  1984年   143篇
  1983年   132篇
  1982年   69篇
  1981年   74篇
  1980年   69篇
  1979年   107篇
  1978年   86篇
  1977年   71篇
  1973年   62篇
  1972年   73篇
  1969年   67篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Electron microscopy and bacteriological culture revealed viable bacteria covered with a glycocalyx (biofilm) in choledochal stones recovered from two patients with acute cholangitis. On the cut surface of the choledochal stones, the cholesterol stone component was surrounded with a layer of brown pigment stone. In each case, bacterial culture of the choledochal stone recoveredPseudomonas aeruginosa. Since alginate is the main component of the glycocalyx produced byP. aeruginosa, serum IgM, IgG and IgA anti-alginate antibodies were measured in each patient. The present study is the first to demonstrate acute and transient IgM seroconversion to alginate in cases of acute cholangitis. In one case, the elevation of anti-alginate IgM preceded the elevation of anti-alginate IgG. The authors propose that the bacterial glycocalyx may play a significant role in acute cholangitis.  相似文献   
82.
The results of treating 12 consecutive patients with unresectable colorectal hepatic metastases with a hepatic arterial infusion of high-dose Adriamycin, 100–120 mg/m2, using hepatic venous isolation (HVI) and charcoal hemoperfusion (CHP) are reported herein. Adriamycin was administered over 5–15 min under extracorporeal drug elimination by HVI-CHP. HVI was percutaneously accomplished by either the double-balloon technique using a Fogarty occlusion catheter (8/22F) or a balloon-tipped catheter (16F). During the infusion, isolated hepatic venous blood was filtered by CHP and pumped into the left axillary vein. There were no lethal complications, and good hemodynamic tolerance to HVI-CHP was confirmed. Tumor liquefaction accompanied by a sharp decrease in serum carcinoembryonic antigen levels by more than 50% of pretreatment levels was observed in 6 of the 12 patients 1 month after treatment. Apart from chemical hepatitis, which developed in 11 (92%) of the patients, the Adriamycin toxicities were well controlled following the development of nausea and vomiting in 2 patients (17%), leukopenia <2,000/mm3 in 3 (25%), and gastric ulcer in 1 (8%). These results indicate that this method is a safe and useful procedure for otherwise hazardous high-dose intraarterial chemotherapy in patients with unresectable hepatic tumors.  相似文献   
83.
Cardiovascular depression occuring when diazepam is combined with fentanyl has been investigated using the benzodiazepine antagonist RO15-1788 in the dog.After the initial administration of fentanyl (40mcg/kg), the mean arterial pressure (MAP) decreased to 89% of its control value. Following the administration of diazepam (1.2mg/kg), the MAP and the total peripheral resistance (TPR) decreased significantly, to 75% and 83% of their control values respectively. After the administration of RO15-1788 (0.4mg/kg), the MAP increased significantly to 90% and the TPR to 102% of their control values and, lastly, the administration of naloxone (40mcg/kg) increased the MAP to 108% of its control value. No relationship was found between the changes in the catecholamines and the changes in the MAP after the administration of fentanyl, diazepam, and RO15-1788.The mechanism of circulatory depression when diazepam was used with fentanyl is interpreted as being a peripheral vasodilatory effect of diazepam acting by way of the benzodiazepine receptors since RO15-1788 was found to antagonize this effect.(Sone T, Kato T, Tsukahara I et al.: The effect of RO15-1788 on cardiovascular depression caused by fentanyl and diazepam. J Anesth 2: 69–76, 1988)  相似文献   
84.
S Kikuchi  O Wada  H Tenjin  Y Inaba 《Gan no rinsho》1989,35(2):202-206
From an observation of personnel we expect epidemiological studies make mass-screening of stomach cancer more efficient and suppose they should be done as to following aspects: (1) To decide the most efficient interval of mass-screening, investigating the frequency distribution of "Saving Duration" on many stomach cancers that is the duration when a stomach cancer is both detectably by screening and curable. (2) To decide who should undergo stomach examination quantifying cancer-risks of individuals with the use of epidemiological results. (3) To make epidemiological studies more sensitive and useful, classifying stomach cancers by microscopic pathological type, macroscopic one or "Saving Duration". (4) To settle a statistical standard of epidemiological results which is demanded for them to be useful in mass-screening.  相似文献   
85.
Patients with acute (2,569) and chronic (957) leukemia diagnosedat 19 institutes took part in the study on the "MultidisciplinaryTreatment of Leukemia" between 1971 and 1985 and were investigatedretrospectively. By dividing the 15 years into three five-yearperiods, we were able to compare patient ratios in the differentperiods. The proportions of acute to chronic leukemia casesshowed no obvious change; however, the proportions of casesdiagnosed as acute lymphocytic leukemia in acute leukemia showeda significant increase. The main chemotherapeutic drugs usedduring the three time periods were cytarabine or its analogues,the anthracyclines, 6-mercaputopurine and prednisolone, againstacute myelogenous leukemia, and the vinca alkaloids, prednisoloneand the anthracyclines against acute lymphocytic leukemia. Therate of complete remission from acute myelogenous leukemia mademarked progress, from 45.1% during 1971–1975 to 62.3%during 1981–1985, but that of acute lymphocytic leukemiashowed no significant progress, being 65% during 1971–1975and 69.7% during 1981–1985. The durations of remission,however, and the survival times for patients with acute lymphocyticleukemia, as well as for those with acute myelogenous leukemia,became significantly longer over the three periods. Median survivaltimes from chronic myelocytic leukemia were 37–40 mo inall three periods, showing no progress. There was a better prognosisin cases of chronic myelocytic leukemia with, than without,Philadelphia chromosome. Except for a low incidence of chroniclymphocytic leukemia in Japan, adult leukemia patients' characteristicsand prognoses seem to be almost the same in Japan as in theU.S.A. and Europe.  相似文献   
86.
A4-moth-old male infant predisposed to allergic dermatitis acquired widespread eczema vaccinatum by contacts with a recently vaccinated sibling. He died of acute purulent peritonitis following a perforation of multiple duodenal ulcers. Fluorescence immunocytochemical and electron microscopic studies on the skin lesions revealed the presence of viral antigens and numerous virus particles compatible morphologically with those of the mature form from the same batch of smallpox vaccine given to the sibling. A large number of virus particles in the developmental form were also predominantly scattered in the cytoplasm of cells at the stratum malpighii of the epidermis as well as in neutrophils and macrophages in the skin lesions. The virus isolation from the skin lesions was done by using the HeLa cells and the human embryonic lung fibroblasts. No abnormal laboratory data were noted in immunoglobulins. On the basis of atrophy of the thymus and other lymphatic tissues and an appearance of large pyroninophilic cells in association with blastoid transformation, the authors discussed a possible participation of the disturbance of cellular immunity secondary to the virus infection in the development of the disease. ACTA PATH. JAP. 29 : 435–455, 1979.  相似文献   
87.
88.
Six solitary gastric polyps in the acid-secreting fundic mucosa were histo-chemically investigated using the mucin histochemistry, immunoperoxidase method, and silver methods for endocrine cells. Histologically, the polyps were grouped into three types : they largely consisted of either hyperplastic foveolar cells (group 1), normal-appearing fundic gland cells with mild cystic changes (group 2) or hyperplastic fundic gland cells with cystic dilatation (group 3). The presence of parietal cells and mucous neck cells was confirmed in all polyps by the immunoperoxidase method using parietal cell autoantibody and the paradoxical Concanavalin A staining, respectively. Regarding the endocrine component, somatostatin-containing cells, Grimelius-positive argyrophil cells, and Fontana-Masson-positive enterochromaffin cells were scattered in the fundic gland area of the polyps as well as in the surrounding normal-appearing fundic mucosa. Gastrin-containing cells were absent. In one of the group 2 polyps and both group 3 polyps, a varying number of glicentin-containing cells were found among the fundic gland components : In one polyp in group 3, glucagon immunoreactivity was detected in the glicentin-containing cells. These findings suggest that some of the polyps express characteristics of the fetal fundic mucosa, since glicentin and glucagon immunoreactivities in normal human stomach have been detected exclusively in the fetal fundus. ACTA PATHOL. JPN. 35: 831–840, 1985.  相似文献   
89.
Argyrophil cells and melanocytes in esophageal mucosa   总被引:5,自引:0,他引:5  
  相似文献   
90.
We examined the possibility that lumbar skin warming can increase gastrointestinal motility by investigating the electrogastrogram (EGG), blood pressure, and heart rate with psychometric ratings in healthy humans. Scores of mood state profiles showed that lumbar skin warming (42 degrees C, 20 min) decreased tension-anxiety, depression, anger-hostility, fatigue, and confusion of the participants. A multiple bandpass filter analysis of EGGs showed that a postural transition from orthostatic to supine for measurement caused an increase in dominant frequency of 25-29% towards the frequencies of the normal interdigestive migrating motor complex (IMC). The spectral power of the IMC band, 2.55-3.05 cycles/min, was increased by 20 min-warming, reflecting the increase in gastric contractility. No increase in the spectral power was observed in the time-matched control group without skin warming. Therefore, an increase in contractility is a characteristic of lumbar skin warming. The systolic blood pressure increased by 15% during warm stimulation. Interbeat intervals were not influenced by warm stimulation. An analysis of interbeat intervals by a fast Fourier transform method showed that the cardiac sympathetic and parasympathetic nerves did not play a major role in raising the blood pressure. Vasoconstriction of the mesenteric artery was therefore considered to cause a blood pressure increase during warming. It is hypothesized that vasoconstriction of the visceral arteries by lumbar skin warming increases the blood pressure and gastrointestinal contractility.  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