全文获取类型
收费全文 | 3377篇 |
免费 | 129篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 78篇 |
妇产科学 | 18篇 |
基础医学 | 411篇 |
口腔科学 | 48篇 |
临床医学 | 218篇 |
内科学 | 1058篇 |
皮肤病学 | 56篇 |
神经病学 | 253篇 |
特种医学 | 118篇 |
外科学 | 558篇 |
综合类 | 8篇 |
预防医学 | 133篇 |
眼科学 | 57篇 |
药学 | 212篇 |
中国医学 | 2篇 |
肿瘤学 | 291篇 |
出版年
2023年 | 9篇 |
2022年 | 46篇 |
2021年 | 68篇 |
2020年 | 44篇 |
2019年 | 57篇 |
2018年 | 73篇 |
2017年 | 52篇 |
2016年 | 63篇 |
2015年 | 80篇 |
2014年 | 97篇 |
2013年 | 121篇 |
2012年 | 182篇 |
2011年 | 210篇 |
2010年 | 112篇 |
2009年 | 106篇 |
2008年 | 172篇 |
2007年 | 215篇 |
2006年 | 203篇 |
2005年 | 206篇 |
2004年 | 159篇 |
2003年 | 198篇 |
2002年 | 198篇 |
2001年 | 60篇 |
2000年 | 52篇 |
1999年 | 62篇 |
1998年 | 56篇 |
1997年 | 39篇 |
1996年 | 39篇 |
1995年 | 31篇 |
1994年 | 38篇 |
1993年 | 24篇 |
1992年 | 50篇 |
1991年 | 55篇 |
1990年 | 33篇 |
1989年 | 32篇 |
1988年 | 25篇 |
1987年 | 30篇 |
1986年 | 28篇 |
1985年 | 18篇 |
1984年 | 24篇 |
1983年 | 24篇 |
1982年 | 23篇 |
1981年 | 13篇 |
1979年 | 13篇 |
1977年 | 9篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1969年 | 6篇 |
1966年 | 5篇 |
排序方式: 共有3529条查询结果,搜索用时 46 毫秒
21.
N. Ishii N. Moriguchi Y. Sugita H. Nakajima S. Tanaka I. Aoki 《Immunological investigations》1993,22(6):451-462
The induction of immune tolerance is the most common consequence of protein feeding, i.e., “oral tolerance”. In this study we investigated the genetic basis of oral tolerance using various kinds of recombinant and congenic mice, and the cells involved in the development of this phenomenon in mice. The footpad swelling response to ovalbumin (OVA) was inhibited in mice that were orally fed OVA 7 days before sensitization. No effect of strain of mouse was seen in this inhibition. This inhibition could be transferred by Peyer's patch cells. The CD4-8+ T cells were responsible for the inhibition of footpad swelling. The number of CD4+ cells from OVA-fed tolerant mice decreased significantly, but CD8+ cells did not.
The number of CD4-8+ T cells was increased in Peyer's patches of OVA-fed tolerant mice, and were involved in the development of oral tolerance. 相似文献
The number of CD4-8+ T cells was increased in Peyer's patches of OVA-fed tolerant mice, and were involved in the development of oral tolerance. 相似文献
22.
Hiromasa Yanagi Jiro Kondo Keiji Uchida Michio Tobe Shin-ichi Suzuki Yoshimi Yano 《General thoracic and cardiovascular surgery》1998,46(10):1014-1019
We experienced a case with acute mitral regurgitation caused by complete posterior papillary muscle rupture as complication of acute inferior myocardial infarction, who underwent successfully emergency operation of mital valve replacement and coronary revascularization in acute stage. A 64-year-old woman developed sudden cardiogenic shock shortly after the onset of acute inferior myocardial infarction. The diagnosis of acute inferior myocardial infarction was based on the electrocardiographic findings. Under IABP support, preoperative coronary angiography visualized total occlusion of segment 3 of the right coronary artery, and preoperative left ventriculography showed akinesis of inferior wall and severe mitral regurgitation. At 6 hours after onset of papillary muscle rupture, emergency operation was performed. At operation, posterior papillary muscle was found to be totally ruptured. Coronary artery revascularization and mitral valve replacement were performed. Postoperative course was uneventful, with 4 days of IABP and 5 days of ventilatory support. She was discharged on the twentieth postoperative day in NYHA class I. Reports of successful emergency operation for total papillary muscle rupture following acute myocardial infarction are rare. Early diagnosis and surgical treatment are mandatory to save this group of patients. 相似文献
23.
Epileptic seizure of El mouse initiates at the parietal cortex: depth EEG observation in freely moving condition using buffer amplifier 总被引:1,自引:0,他引:1
The initiation site of seizure discharges and the relationship between behavioral manifestations and electroencephalography were investigated in the El mouse, a hereditary epilepsy model. The chronic depth electrodes were implanted stereotaxically into the frontal cortex, parietal cortex, temporal cortex, hippocampus, striatum, amygdaloid complex, non-specific nuclei of thalamus and substantia nigra. Electrical activities were recorded in freely moving condition with use of the buffer amplifier devised in the laboratory and behaviors were monitored simultaneously. Seizure spike discharges started in the parietal cortex and spread out into other brain areas. When the hippocampus was involved, the tonic convulsion occurred behaviorally. The paper describes the first direct evidence of the initiation and propagation of seizure discharges in the brain of El mouse. 相似文献
24.
Thomazi AP Godinho GF Rodrigues JM Schwalm FD Frizzo ME Moriguchi E Souza DO Wofchuk ST 《Mechanisms of ageing and development》2004,125(7):475-481
The excitotoxicity of the neurotransmitter glutamate has been shown to be connected with many acute and chronic diseases of the CNS. High affinity sodium-dependent glutamate transporters play a key role in maintaining adequate levels of extracellular glutamate. In the present study, we used slices of striatum, hippocampus and cortex from rat brain to describe the in vitro profile of glutamate uptake during development and ageing, and its sensitivity to guanosine. In all structures, glutamate uptake was higher in immature animals. There was a maximum decrease in glutamate uptake in striatum and hippocampus in 15-month-old rats, which later increased, while in cortex there was a significant decrease in rats aged 60 days old. The effect of guanosine seems to be age and structure dependent since the increase in basal glutamate uptake was only seen in slices of cortex from 10-day-old animals. 相似文献
25.
Takahashi S Hitomi J Satoh Y Takahashi T Asakura H Ushiki T 《Archives of histology and cytology》2002,65(1):71-82
The hepatic portal vein has been known to make a spontaneous peristaltic movement in some mammals, including the mouse and rat. To investigate the fine structure of the portal vein in relation to its physiological characteristics, we observed the mouse portal vein by using various histological techniques including conventional light microscopy, videomicroscopy, transmission and scanning electron microscopy, and real-time confocal laser scanning microscopy. The mouse hepatic portal vein was provided with a spiral fold which was produced by the inner layer, i.e. the endothelium and smooth muscles of the wall protruding into the lumen. Longitudinal smooth muscle cells spanned the interval of the fold, like a spirally arranged palisade around the vessel wall. The longitudinal muscle fibers ended at the spiral fold, being partly connected with a network of irregularly shaped smooth muscle cells. This network, hitherto unknown, was recognized to be restricted to the fold in distribution and characterized by numerous gap junctions connecting the muscle cells. Real-time confocal laser scanning microscopy using a Ca2+ sensitive fluorescent dye revealed that a transient and periodic increase in Ca2+ concentration occurred in the longitudinal smooth muscle cells and was transmitted spirally from the intestinal to the hepatic side. These findings indicate that, during the peristaltic movement, the contraction of smooth muscle cells is transmitted along the longitudinal smooth muscles of the portal vein wall toward the liver, presumably controlled by the network of the irregularly-shaped smooth muscle cells in the fold of the portal vein. Light microscopic observation in some specimens indicated an occurrence of cardiac muscle cells outside the smooth muscle layer. Restricted to the site of the porta hepatis in distribution, their involvement in the peristaltic contraction of the portal vein seemed unlikely. 相似文献
26.
Yuzo Okumura Jiro Kudo Tohru Ikuta Satoshi Kurokawa Hiromi Ishibashi Hideo Okubo 《Inflammation》1985,9(2):211-219
The effects of
1-antitrypsin (
1,-AT),
1,-acid glycoprotein (
1AGP), and haptoglobin (Hp), the main constituents of-globulin and which belong to acute phase proteins, on NK activity were examined using K562 cells as the NK target cells. Among the three proteins,
1,-AT and
1AGP had inhibitory effects on NK activity for fast target K562 cells. The,-AT preparations having the same protein concentration and a different trypsin inhibitory capacity (TIC) had an equal effect. Although
1AT and
1,-AGP equally reduced the NK activity, the mechanism involved in the reduction differed, in that the effect of
1,-AT directed toward NK cells reduced their binding capacity with the target cells,
1,-AGP probably interacts with a cytotoxic factor secreted from NK cells following effector-target interaction. These studies suggest that each of the acute-phase proteins, which increase following inflammation, inhibits NK cell function by two distinct mechanisms. 相似文献
27.
Wakabayashi Y Watanabe H Inoue J Takeda N Sakata J Mishima Y Hitomi J Yamamoto T Utsuyama M Niwa O Aizawa S Kominami R 《Nature immunology》2003,4(6):533-539
The gene Bcl11b, which encodes zinc finger proteins, and its paralog, Bcl11a, are associated with immune-system malignancies. We have generated Bcl11b-deficient mice that show a block at the CD4-CD8- double-negative stage of thymocyte development without any impairment in cells of B- or gammadelta T cell lineages. The Bcl11b-/- thymocytes showed unsuccessful recombination of V(beta) to D(beta) and lacked the pre-T cell receptor (TCR) complex on the cell surface, owing to the absence of Tcrb mRNA expression. In addition, we saw profound apoptosis in the thymus of neonatal Bcl11b-/- mice. These results suggest that Bcl11b is a key regulator of both differentiation and survival during thymocyte development. 相似文献
28.
M Imai T Shibata K Moriguchi M Yamamoto H Hayama 《Okajimas folia anatomica Japonica》1991,68(2-3):155-160
Some researchers have already described the fowl proventriculus. However, we believed there was a need for detailed carbohydrate histochemical investigations on the same glands. Moreover, some researchers had erred about the lamina muscularis mucosae. The results of these investigations are as follows. 1. The proventricular glands consist of both superficial and profound gastric glands. 2. The superficial glands are distributed in the lamina propria mucosae while the profound glands exist in the tela submucosa. 3. The superficial glands are simple, branched tubular glands. The columnar glandular cells are arranged in a simple layer and react strongly to PAS, AB (pH 2.5 and 0.5). These appear to be dark purple when they are stained with PAS-AB (pH 2.5). Some other methods have also been tried. 4. Judging from the data 3), the superficial gastric glands contain neutral, weak and strong acids, sulfuric and acid mucopolysaccharides, sialomucin, and II and III neutral mucus type. 5. Glandular cells in the body and basal portions of the superficial gastric glands contain a large number of fine pepsinogen granules. 6. Judging from the data of 3)-5), we believe that the superficial gastric glands are undifferentiated gastric glands and that they are same kinds of glands that are found in mammals. 7. A large number of profound gastric glands fill the tela submucosa. They are compound tubular glands, and are composed of many glandular alveoli. Their columnar glandular cells are arranged in a simple layer. 8. These glandular cells react moderately to PAS, negatively to AB (pH 2.5 and 0.5) and PAS-AB (pH 2.5). Moreover, we observed some other reactions.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
29.
Yuji Mizukami Fujitsugu Matsubara Takuma Hashimoto Jiro Okumura Shigeru Matsukawa Kiyoo Tanishima 《Pathology international》1987,37(2):253-260
Amylase activity was measured in thyroid tissues of various thyroid diseases and was analysed electrophoretically. Normal thyroid tissues contained significant amounts of amylase (mean ± SD; 2.71 ± 1.15 lU/g of tissue), and their amylase isozyme was composed of a majority of salivary type isoamylase and other peculiar isoamylase. The statistical decrease of amylase activities in tissues of Graves' disease under hyperthyroldism, thyroid carcinoma, and most of thyroid adenomas were found (Graves' disease; 1.04 ± 0.41, carcinoma; 1.49 ± 1.10, adenoma (except five cases with high activity); 0.88 ± 0.49 IU/g tissue). Five of 18 cases of adenoma showed strikingly higher amylase activity in their tissues. Electrophoretical patterns of amylase isoenzymes in these five adenoma tissue were different from those of normal thyroid tissues. The cellular localization of amylase in the normal thyroid tissues and the adenoma tissues was also demonstrated immunohlstochemically. 相似文献
30.
Takamatsu S Teramoto K Kawamura T Kudo A Noguchi N Irie T Ochiai T Kumagai J Koike M Arii S 《Pathology international》2004,54(6):440-445
Intrabiliary growth of liver metastases from colorectal cancer has rarely been studied. A surgically resected case of a metastatic liver tumor with prominent intrabiliary growth derived from rectal cancer is reported. The patient was a 62-year-old man who had received a low anterior resection for rectal cancer in March 2000. He was re-admitted due to obstructive jaundice in January 2003, and was diagnosed with hepatic malignancy in segment II of the liver with an intrabiliary tumor extending from the intrahepatic bile duct of segment II to the common hepatic duct. He underwent a left hepatectomy, a partial resection of segment VI, and an extrahepatic bile duct resection with reconstruction of the biliary tract. In the resected specimen, there were whitish tumors of 3 cm and 1.5 cm in diameter in segments II and VI, respectively, and an intrabiliary tumor originating from the main tumor in segment II extended to the common hepatic duct. Both the liver tumors and the intrabiliary tumor consisted of a well- to moderately differentiated adenocarcinoma, which showed the same histological features as the rectal cancer. The immunohistochemical findings strongly supported that these tumors, including the intrabiliary growth, were liver metastasis from the rectal cancer. The intrabiliary invasion and growth of metastatic liver tumors has generally been overlooked, notwithstanding their frequently observed biological behavior. The present case is informative, and further investigation into this type of metastatic liver tumor may be warranted. 相似文献