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   3435篇
  免费   152篇
  国内免费   2篇
耳鼻咽喉   25篇
儿科学   66篇
妇产科学   34篇
基础医学   444篇
口腔科学   114篇
临床医学   249篇
内科学   842篇
皮肤病学   82篇
神经病学   242篇
特种医学   49篇
外科学   537篇
综合类   5篇
预防医学   83篇
眼科学   63篇
药学   253篇
中国医学   5篇
肿瘤学   496篇
  2023年   18篇
  2022年   24篇
  2021年   59篇
  2020年   34篇
  2019年   43篇
  2018年   70篇
  2017年   45篇
  2016年   64篇
  2015年   64篇
  2014年   64篇
  2013年   85篇
  2012年   156篇
  2011年   199篇
  2010年   91篇
  2009年   82篇
  2008年   159篇
  2007年   196篇
  2006年   214篇
  2005年   203篇
  2004年   230篇
  2003年   208篇
  2002年   176篇
  2001年   91篇
  2000年   90篇
  1999年   88篇
  1998年   53篇
  1997年   31篇
  1996年   34篇
  1995年   38篇
  1994年   33篇
  1993年   34篇
  1992年   53篇
  1991年   62篇
  1990年   56篇
  1989年   61篇
  1988年   63篇
  1987年   58篇
  1986年   40篇
  1985年   39篇
  1984年   44篇
  1983年   30篇
  1982年   14篇
  1981年   8篇
  1980年   16篇
  1979年   8篇
  1978年   7篇
  1977年   13篇
  1976年   7篇
  1968年   5篇
  1966年   7篇
排序方式: 共有3589条查询结果,搜索用时 15 毫秒
11.
Langerhans cell histiocytosis is currently regarded as a reactive proliferative process of Langerhans cells rather than a malignancy. The disease is characterized by Langerhans cell infiltration of skin, lung, bone and other organs. We report a 74-year-old man with Langerhans cell histiocytosis who had generalized hemorrhagic and crusted papules. He also had diabetes insipidus. Because he did not have any severe constitutional symptoms or failure of vital organs, we applied topical PUVA treatment to his skin lesions, which responded well to the therapy. Diabetes insipidus, however, remained, in spite of X ray radiotherapy for the pituiary lesion.  相似文献   
12.
13.
14.
15.
16.
M Miyauchi  K Maruyama 《Gan no rinsho》1988,34(9):1089-1095
Twelve cases of the chordoma, including 4 cases with metastases, have been examined by light and electron microscopy for a comparison with 5 cases of the human notochord. Observed similarities in the histological and ultrastructural characteristics of the chordoma with those of the notochord suggested the histogenetic origin of the chordoma from the remnant of notochord. A "diffuse pattern" that was seen in the histological appearance of 4 cases of the chordoma, including 2 cases with metastases, was not observed in the notochord and was considered to indicate the malignant nature of such chordoma. Electron microscopy of the physaliphorous cells characteristic of the chordoma demonstrated intracytoplasmic large vacuoles containing glycogen.  相似文献   
17.
The hepatic transports of 4-methylumbelliferone (4-MU) and its conjugative metabolites, the glucuronide (4-MUG) and sulfate (4-MUS), were investigated in rats with various methods. The extraction ratio (E) was estimated with the multiple indicator dilution (MID) method using isolated perfused rat liver. The values of E for 4-MUG and 4-MUS were much lower (less than 0.2) than that for the parent compound, 4-MU (0.89). In addition, we examined the simulation of the outflow curves of conjugates based on the "distributed" model in which we varied the permeability between the blood and hepatocytes. When the permeability was much smaller relative to the hepatic blood flow, the simulated curve was superimposed on the dilution curve. These results suggest that the influx permeabilities of these conjugates are so low that little extraction occurs during the passage through the liver. Measuring the unidirectional uptake of these conjugates into the liver with the in vitro centrifugal filtration method using isolated hepatocytes, we determined the influx permeabilities (PSinf(total] for the total ligands. The value of PSinf(total) determined with the in vitro method was extrapolated to that per gram of liver, assuming 1 g of liver has 1.3 X 10(8) cells. The values of PSinf(total) for 4-MU, 4-MUG, and 4-MUS were 4.8, 0.06, and 0.11 mL/min/g liver, respectively. Thus, the influx permeabilities for 4-MUG and 4-MUS were much smaller than the hepatic blood flow (1.6 mL/min/g liver), confirming the results of MID method.  相似文献   
18.
Transcatheter arterial embolization (TAE) with the concurrent use of caerulein was assessed for the purpose of preventing gallbladder complications often seen after TAE of hepatic carcinoma. Ninety-six cases with primary hepatic carcinoma, who had undergone TAE in the right hepatic arterial region over the past 4 years, were divided into three groups: 22 cases for which embolization was possible on a selective basis by passing the catheter to the peripheral side beyond the bifurcated region of the cystic artery; 40 cases who had undergone TAE in which caerulein was not administered, from the central side of the bifurcated region of the cystic artery; and 34 cases given 20 g caerulein 15–30 min before TAE. A comparison was made using the abdominal pain, pyrexia, rate of leukocytosis and the US findings of the gallbladder as the indices of the gallbladder complications. As a result, it become evident that it was possible to prevent or alleviate gallbladder complications if caerulein were administered before TAE in cases where the embolizing substances were infused in the right hepatic artery from the central side of the bifurcated region of the cystic artery. It was conclusively shown that the gallbladder blood flow decreases if the organ is contracted by caerulein, which in turn causes a decrease in the inflow of the embolizing substances whereby complications are alleviated.  相似文献   
19.
AIMS: p27 is a prominent regulator of cell proliferation by universally inhibiting the cell cycle, while Jun activation domain-binding protein 1 (Jab1), a multifunctional cell signaling protein, contributes to carcinoma progression by degrading p27. In this study, we investigated the expression of these proteins in medullary thyroid carcinoma. METHODS: We immunohistochemically examined Jab1 and p27 expression in 64 medullary thyroid carcinomas. RESULTS: Of the 64 cases examined, decreased p27 expression was observed in 38 cases (59.4%). The p27 expression level was inversely linked to tumour size as well as plasma calcitonin level. Jab1 expression level was generally high, and 46 cases (71.9%) were classified as overexpressing Jab1. The incidence was higher than those in papillary and follicular carcinomas, which were previously reported. Jab1 expression level was inversely linked to that of p27, and all five cases with only cytoplasmic but not nuclear staining of p27 overexpressed Jab1. CONCLUSIONS: These findings suggest that (1) decrease in p27 expression may contribute to local tumour growth; (2) Jab1 expression is related to the progression of medullary carcinoma by decreasing the amount of p27 in the cell and accelerating its degradation; and (3) Jab1 may play a more vital role in the pathogenesis of medullary carcinoma than papillary and follicular carcinomas.  相似文献   
20.
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