全文获取类型
收费全文 | 7971篇 |
免费 | 438篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 162篇 |
妇产科学 | 94篇 |
基础医学 | 993篇 |
口腔科学 | 162篇 |
临床医学 | 649篇 |
内科学 | 2381篇 |
皮肤病学 | 73篇 |
神经病学 | 659篇 |
特种医学 | 236篇 |
外科学 | 1208篇 |
综合类 | 23篇 |
预防医学 | 197篇 |
眼科学 | 142篇 |
药学 | 519篇 |
中国医学 | 25篇 |
肿瘤学 | 903篇 |
出版年
2023年 | 44篇 |
2022年 | 110篇 |
2021年 | 180篇 |
2020年 | 73篇 |
2019年 | 130篇 |
2018年 | 166篇 |
2017年 | 148篇 |
2016年 | 151篇 |
2015年 | 205篇 |
2014年 | 199篇 |
2013年 | 221篇 |
2012年 | 409篇 |
2011年 | 495篇 |
2010年 | 223篇 |
2009年 | 201篇 |
2008年 | 381篇 |
2007年 | 429篇 |
2006年 | 367篇 |
2005年 | 429篇 |
2004年 | 360篇 |
2003年 | 385篇 |
2002年 | 408篇 |
2001年 | 243篇 |
2000年 | 299篇 |
1999年 | 215篇 |
1998年 | 117篇 |
1997年 | 70篇 |
1996年 | 91篇 |
1995年 | 71篇 |
1994年 | 74篇 |
1993年 | 60篇 |
1992年 | 167篇 |
1991年 | 151篇 |
1990年 | 128篇 |
1989年 | 159篇 |
1988年 | 114篇 |
1987年 | 95篇 |
1986年 | 94篇 |
1985年 | 89篇 |
1984年 | 55篇 |
1983年 | 59篇 |
1982年 | 31篇 |
1981年 | 31篇 |
1980年 | 34篇 |
1979年 | 47篇 |
1978年 | 26篇 |
1976年 | 23篇 |
1975年 | 26篇 |
1972年 | 22篇 |
1971年 | 19篇 |
排序方式: 共有8466条查询结果,搜索用时 15 毫秒
991.
992.
During the period from August, 1977 to December, 1984, a total of 3003 patients who received open heart surgery were treated postoperatively at the ICU of National Cardiovascular Center. Low cardiac output syndrome (LOS) developed in 669 (22.3%) patients. Organ failures due to LOS were studied in these patients. Although the overall mortality of postoperative patients was 5.6% and improved to around 4% in the later years, death rate of patients with LOS was persistently high (22.8%) and showed no tendency to improve even in the latest years. Moreover, the clinical results of those LOS patients who developed organ failure were extremely poor; the mortality of patients with respiratory failure (RF) accounted for 36.8% and that of patients with other organ failure exceeded 50%. The incidence of impaired organs in LOS patients was 49.9% in RF, 29.9% in acute renal failure (ARF), 18.4% in hepatic failure (HF), 16.4% in disseminated intravascular coagulation (DIC), 15.5% in central nervous system failure (CNSF), and 11.1% in gastrointestinal bleeding (GIB). Pathophysiological mechanisms as well as the management of these major complications caused by LOS are also discussed. Some patients developed multiple organ failure (MOF). Plasma exchange (PE) was performed on 16 patients who developed MOF. Improvement of various organ functions was obtained and consequently three patients were successfully treated by means of PE. Removal of various substances toxic to organs, supplement of deficient substances and cessation of the vicious cycle produced by the interaction of impaired organs in patients with MOF are major roles of PE in the treatment of MOF. 相似文献
993.
We traced the origin of lymphatic capillaries of the chordae tendineae by serial ultrathin sections and electron microscopy of lymphatics identified first by light microscopy at the base of the chordae tendineae. Most of the lymphatics appear flattened in cross section, approximately 15 to 20 microns and 3 to 5 microns in greater and lesser diameters, respectively. Spiny (thorn-like) branchlets (about 10 microns in length) randomly projected from the sides of straight lymphatic capillaries and each was composed of a single endothelial cell with marginal zones in apposition to one another. The extreme end of a straight lymphatic capillary terminated blindly and consisted of a single endothelial cell with an ultrastructural appearance that resembled that of the spiny branchlets. 相似文献
994.
Effects of procaine on pharmaco-mechanical coupling mechanisms activated by acetylcholine in smooth muscle cells of porcine coronary artery 总被引:3,自引:0,他引:3
The action of procaine on pharmaco-mechanical coupling activated by application of acetylcholine (ACh) was investigated using collagenase-treated dispersed intact and skinned smooth muscle cells and intact muscle tissues of the porcine coronary artery. ACh reduced stored 45Ca2+, and this action was prevented by procaine in intact dispersed cells. The maximum reduction in the level of stored 45Ca induced by caffeine (25 mM) or inositol 1,4,5-trisphosphate (InsP3; 3 microM) was also prevented by procaine in the skinned muscle cells in the presence or absence of ATP. However, inhibitions of the latter required higher concentrations of procaine than the former. Release by 10 microM ACh of Ca2+ from its store site in the presence or absence of extracellular Ca2+ was also inhibited by procaine and was detected using the quin2 fluorescence method. In these smooth muscle tissues, ACh (above 10 nM) reduced the amount of phosphatidylinositol 4,5-bisphosphate (PI-P2) and dose dependently increased the amount of phosphatidic acid. Procaine inhibited the hydrolysis of PI-P2 activated by ACh, thus reducing the amount of InsP3 and the release of Ca2+ from the store site. It is concluded that procaine has multiple actions on the porcine coronary artery, and one of the actions related with pharmacomechanical coupling appears through inhibition of hydrolysis of PI-P2 induced by ACh. 相似文献
995.
H Takahashi R C Koehler T Hirata S W Brusilow R J Traystman 《Circulation research》1992,71(5):1220-1230
Hyperammonemia increases brain glutamine levels, causes astrocytic swelling, and depresses cerebral blood flow (CBF) responsivity to CO2. Methionine sulfoximine (MSO) inhibition of glutamine synthetase activity, known to be enriched in astrocytes, prevents ammonia-induced increases in brain glutamine and water content. We tested the hypothesis that inhibition of glutamine accumulation restores CBF responsivity to CO2 during acute hyperammonemia. Pentobarbital-anesthetized rats treated with either vehicle or MSO (150 mg/kg i.p.) received a 6-hour intravenous infusion of either sodium or ammonium acetate. With subsequent induction of hypercapnia, CBF increased from 113 +/- 14 (mean +/- SEM) to 194 +/- 9 ml/min per 100 g in control rats but was unchanged from 107 +/- 13 to 79 +/- 10 ml/min per 100 g in hyperammonemic rats. Treatment with MSO in hyperammonemic rats restored the CBF response to hypercapnia (from 73 +/- 8 to 141 +/- 14 ml/min per 100 g). With induction of hypocapnia, CBF decreased from 114 +/- 11 to 88 +/- 11 ml/min per 100 g in control rats but increased from 112 +/- 13 to 142 +/- 19 ml/min per 100 g in hyperammonemic rats. Treatment with MSO in hyperammonemic rats did not fully restore the response to hypocapnia but prevented the paradoxical increase in CBF (from 80 +/- 8 to 80 +/- 8 ml/min per 100 g). In control rats, MSO did not affect CO2 responsivity. Treatment with MSO prevented ammonia-induced increases in intracranial pressure. Hyposmotic-induced increases in brain water content and intracranial pressure attenuated the CBF response to hypercapnia but, unlike hyperammonemia, did not attenuate the response to hypocapnia. In contrast to hypercapnia, vasodilation in response to arterial hypotension was intact in hyperammonemic rats. We conclude that the grossly abnormal CBF responsivity to CO2 alterations during hyperammonemia is linked to glutamine accumulation rather than ammonia per se. Cerebral edema secondary to glutamine accumulation may contribute in part to abnormal CBF responses, although other aspects of astrocyte dysfunction are likely to be important. 相似文献
996.
997.
The number of bone marrow-derived fibroblastoid colony-forming cells (CFU-F) and the production of colony-stimulating activity (CSA) by bone marrow stromal cells were studied in 71 patients with myeloproliferative disorders (MPD). The numbers of CFU-F in chronic-phase chronic myelogenous leukemia (CML), polycythemia vera (PV) and essential thrombocythemia (ET) were not different from those in normal subjects. However, the number of CFU-F in acute-phase CML was markedly decreased. Bone marrow adipocyte colony-forming capacity (adipo-CFC), which was previously shown to reflect both the number of preadipocytes and the stromal cell function in vivo, was increased in patients with chronic-phase CML, PV and ET, but was absent in acute-phase CML patients. The production of CSA by marrow stromal cells of MPD patients, however, was not different from that of normal subjects. These results suggest that the characteristics of marrow stromal and its precursor cells of chronic-phase MPD patients were not different from those of normal subjects, however, they became changed in acute-phase CML patients. 相似文献
998.
Kawakami M Mukaiya M Kimura Y Hata F Katsuramaki T Sasaki K Ura H Hirata K 《Hepato-gastroenterology》2002,49(46):1030-1032
A 45-year-old man was suffering from abdominal pain and vomiting. He was admitted to our hospital with a diagnosis of ileus and obstructive jaundice. He had undergone Roux-en-Y anastomosis for choledocholithiasis 14 years earlier. A computed tomography scan revealed a dilated afferent loop and dilated intrahepatic bile duct. Upper gastrointestinal examination with contrast medium and percutaneous transhepatic cholangiography showed a high intestinal obstruction around the jejunojejunal anastomosis. The patient underwent laparotomy based on a diagnosis of obstructive jaundice due to ileus. During the operation, he was found to have internal herniation of the small bowel through a rent in the mesentery around the Roux-en-Y anastomosis for choledochojejunostomy. The hernia was reduced, and bowel resection was performed due to stenosis of the afferent loop. Jejunojejunal anastomosis was re-performed and the defect in the mesocolon was closed. Internal herniation after Roux-en-Y anastomosis is a rare sequela, but it should be recognized that this complication can occur after Roux-en-Y anastomosis. For prevention of internal herniation around the Roux-en-Y limb, secure closing of the mesenteric defects is important. 相似文献
999.
Hirata K Kubo J Arai M Suga T Tanaka H Yamazaki K 《Internal medicine (Tokyo, Japan)》2000,39(10):852-855
A case of basilar migraine (BM) with alternate numbness as the initial symptom is described. The patient's chief complaint was alternate numbness in the right and left upper extremities. After angiography the patient fell into a drowsy state, followed by excitation, and finally confusion. The EEG power topography showed slow alpha, theta and delta power in the right occipital area, and alternatively in the right and left parietal area. These findings suggest that the cause of BM is not only based on a vasoconstriction mechanism, but also cortical spreading depression. BM should be suspected as a cause of sensory symptoms. 相似文献
1000.
S Niimura T Hirata O Zaha H Nakamura A Kouchi T Uehara H Uechi J Ohshiro K Shikiya F Kinjo 《Kansenshōgaku zasshi. The Journal of the Japanese Association for Infectious Diseases》1992,66(9):1231-1235
We reported the efficacy of albendazole (ABZ) for the treatment of 27 patients with strongyloidiasis. Twenty-seven patients, 23 males and 4 females, received 200 mg of ABZ one hour before breakfast and supper for 3 days and this treatment was repeated 2 weeks later. The following results were obtained: 1) The eradication rate at 2 weeks after the initial treatment was 70.4% (19 of 27 patients) and 2 weeks after the second course was 66.7% (16 of 24 patients). 2) One patients (3.7%) complained of abdominal pain after the first treatment. Four patients (14.8%) complained of headache (n = 2), nausea (n = 1) and exanthema (n = 1) after the second treatment. But all symptoms were mild and required no treatment and subsided in a few days. 3) Positive rate of HTLV-1 antibody was 45.8% in the patients. As described above, side effects occurred in some cases, although they were mild and transient. From these results, it can be concluded that on increased dose of ABZ could be much more favorable for the treatment of strongyloidiasis. 相似文献