全文获取类型
收费全文 | 3299篇 |
免费 | 151篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 62篇 |
妇产科学 | 44篇 |
基础医学 | 386篇 |
口腔科学 | 113篇 |
临床医学 | 203篇 |
内科学 | 747篇 |
皮肤病学 | 59篇 |
神经病学 | 282篇 |
特种医学 | 131篇 |
外科学 | 543篇 |
综合类 | 19篇 |
预防医学 | 70篇 |
眼科学 | 21篇 |
药学 | 287篇 |
中国医学 | 5篇 |
肿瘤学 | 476篇 |
出版年
2023年 | 21篇 |
2022年 | 23篇 |
2021年 | 66篇 |
2020年 | 23篇 |
2019年 | 33篇 |
2018年 | 72篇 |
2017年 | 42篇 |
2016年 | 31篇 |
2015年 | 51篇 |
2014年 | 67篇 |
2013年 | 78篇 |
2012年 | 129篇 |
2011年 | 121篇 |
2010年 | 70篇 |
2009年 | 67篇 |
2008年 | 130篇 |
2007年 | 119篇 |
2006年 | 125篇 |
2005年 | 145篇 |
2004年 | 142篇 |
2003年 | 130篇 |
2002年 | 144篇 |
2001年 | 98篇 |
2000年 | 127篇 |
1999年 | 110篇 |
1998年 | 49篇 |
1997年 | 33篇 |
1996年 | 45篇 |
1995年 | 40篇 |
1994年 | 46篇 |
1993年 | 33篇 |
1992年 | 101篇 |
1991年 | 97篇 |
1990年 | 83篇 |
1989年 | 86篇 |
1988年 | 93篇 |
1987年 | 66篇 |
1986年 | 72篇 |
1985年 | 71篇 |
1984年 | 40篇 |
1983年 | 54篇 |
1981年 | 22篇 |
1979年 | 31篇 |
1977年 | 21篇 |
1974年 | 16篇 |
1973年 | 18篇 |
1972年 | 20篇 |
1971年 | 15篇 |
1967年 | 17篇 |
1966年 | 14篇 |
排序方式: 共有3461条查询结果,搜索用时 218 毫秒
991.
992.
993.
Kajimoto Y Ohta T Miyake H Matsukawa M Ogawa D Nagao K Kuroiwa T 《Journal of neurosurgery》2000,93(4):614-617
OBJECT: The purpose of this study is to clarify the whole pressure environment of the ventriculoperitoneal (VP) shunt system in patients with successfully treated hydrocephalus and to determine which factor of the pressure environment has a preventive effect on overdrainage. METHODS: Thirteen patients with hydrocephalus who had been treated with VP shunt therapy by using a Codman-Hakim programmable valve without incidence of overdrainage were examined. The authors evaluated intracranial pressure (ICP), intraabdominal pressure (IAP), hydrostatic pressure (HP), and the perfusion pressure (PP) of the shunt system with the patients both supine and sitting. With patients supine, ICP, IAP, and HP were 4.6 +/- 3 mm Hg, 5.7 +/- 3.3 mm Hg, and 3.3 +/- 1 mm Hg, respectively. As a result, the PP was only 2.2 +/- 4.9 mm Hg. When the patients sat up, the IAP increased to 14.7 +/- 4.8 mm Hg, and ICP decreased to-- 14.2 +/- 4.5 mm Hg. The increased IAP and decreased ICP offset 67% of the HP (42.9 +/- 3.5 mm Hg), and consequently the PP (14 +/- 6.3 mm Hg) corresponded to only 33% of HP. CONCLUSIONS: The results observed in patients indicated that IAP as well as ICP play an important role in VP shunt therapy and that the increased IAP and the decreased ICP in patients placed in the upright position allow them to adapt to the siphoning effect and for overdrainage thereby to be avoided. 相似文献
994.
Urinary trypsin inhibitor reduces C-X-C chemokine production in rat liver ischemia/reperfusion 总被引:10,自引:0,他引:10
Yamaguchi Y Ohshiro H Nagao Y Odawara K Okabe K Hidaka H Ishihara K Uchino S Furuhashi T Yamada S Mori K Ogawa M 《The Journal of surgical research》2000,94(2):107-115
BACKGROUND AND AIM: Protease inhibitors attenuate ischemia/reperfusion injury. However, the underlying mechanisms by which protease inhibitors prevent reperfusion injury remain obscure. Neutrophils play an important role in reperfusion injury. We studied the effects of urinary trypsin inhibitor (UTI) on production of the C-X-C chemokine, cytokine-induced neutrophil chemoattractant (CINC), by Kupffer cells during ischemia/reperfusion of the liver. METHODS: Liver ischemia was induced in rats by occlusion of the portal vein for 30 min. UTI (50,000 U/kg) was injected intravenously 5 min before vascular clamping. Serum CINC concentrations were measured by enzyme-linked immunosorbent assay. Levels of CINC mRNA in the liver were determined by Northern blot analysis. We also examined the inhibitory effects of UTI on in vitro CINC production by peritoneal macrophages in response to neutrophil elastase (NE). RESULTS: Serum CINC concentrations increased and peaked 6 h after reperfusion. However, pretreatment of animals with UTI blunted this increase in CINC and significantly reduced CINC mRNA levels in the liver after ischemia/reperfusion. UTI also decreased neutrophil accumulation in the liver 24 h after reperfusion. In vitro CINC production by Kupffer cells from rats pretreated with UTI 3 h after ischemia/reperfusion was significantly decreased compared to those from untreated animals. UTI reduced NE activity in vitro in a dose-dependent manner, and UTI significantly reduced in vitro CINC production by peritoneal macrophages stimulated with NE. CONCLUSION: UTI reduces the production of CINC by Kupffer cells stimulated with NE, attenuating ischemia/reperfusion injury of the liver. 相似文献
995.
Bunzo Nakata Yasushi Mitachi Akihito Tsuji Susumu Yamamitsu Koichi Hirata Tetsuhiko Shirasaka Kosei Hirakawa 《Clinical cancer research》2004,10(5):1664-1669
PURPOSE: The Japanese Foundation for Multidisciplinary Treatment of Cancer conducted a Phase I study of a novel oral fluorouracil derivative, S-1, combined with a low dose of cisplatin in unresectable and recurrent gastric cancer. EXPERIMENTAL DESIGN: S-1 was administered orally at 80-120 mg/body/day, depending on body surface area. One course consisted of consecutive administration for 28 days followed by a rest of 14 days. Low-dose cisplatin was given i.v. on days 1-5, 8-12, 15-19, and 22-26 of each course. The dose escalation of cisplatin began with an initial dose of 1 mg/m(2)/day as level 1 and was stepped up to 2, 3, 4, and 6 mg/m(2)/day as level 2, 3, 4, and 5, respectively. The regimen was repeated for at least two courses. RESULTS: A total of 24 patients was entered in the study. There was no treatment-related death. At level 5, consisting of 5 evaluable patients, dose-limiting toxicity was experienced as grade 3 appetite loss in 2 patients and grade 4 neutropenia in 1 patient. The maximum-tolerated dose of cisplatin was estimated to be 6 mg/m(2)/day. We decided on a recommended dose of cisplatin of 4 mg/m(2)/day because the dosage was one level under the maximum-tolerated dose. All 3 patients at level 4 showed partial response, suggesting promising clinical efficacy with this dosage. The serum concentration of cisplatin at level 4 was 918 +/- 92 ng/ml on day 26 of the first course. CONCLUSIONS: S-1 with low-dose cisplatin may become an effective regimen with acceptable toxicity for gastric cancer. 相似文献
996.
Taku Takeuchi Michiyoshi Hisanaga Mitsuo Nagao Naoya Ikeda Hisao Fujii Fumikazu Koyama Tomohide Mukogawa Hiroshi Matsumoto Shunya Kondo Chiaki Takahashi Makoto Noda Yoshiyuki Nakajima 《Clinical cancer research》2004,10(16):5572-5579
PURPOSE: RECK, a membrane-anchored regulator of matrix metalloproteinases (MMPs), is widely expressed in healthy tissue, whereas it is expressed at lower levels in many tumor-derived cell lines. Studies in mice and cultured cells have shown that restoration of RECK expression inhibits tumor invasion, metastasis, and angiogenesis. However, the clinical relevance of these findings remains to be fully documented. Here we examined the expression of RECK and one of its targets, MMP-9, in colorectal cancer tissue. EXPERIMENTAL DESIGN: The RECK and MMP-9 expression levels in colorectal cancer samples from 53 patients were determined by immunohistochemical techniques. The expression level of each protein was scored, and the patients were divided into two groups based on these scores. In 33 cases, we performed gelatin zymography to estimate the degree of MMP-2 and MMP-9 activation. Microvessel density and vascular endothelial growth factor (VEGF) expression were also evaluated histologically. RESULTS: RECK protein was detected in 30 of 53 (56.6%) specimens. Importantly, patients with tumors expressing relatively high levels of RECK (high-RECK group) had a significantly lower risk of recurrence than did patients with tumors expressing relatively low levels of RECK (low-RECK group; P = 0.011). Moreover, RECK-dominant (RECK score > or = MMP-9 score) patients showed a significantly lower incidence of recurrence than did MMP-9-dominant patients (P = 0.0003). Multivariate analysis revealed that the RECK/MMP-9 balance was an independent prognostic factor (P = 0.0122). The expression of VEGF and microvessel density were inversely correlated with the level of RECK expression. CONCLUSIONS: RECK/MMP-9-balance is an informative prognostic indicator for colorectal cancer. Our data also suggest that RECK suppresses tumor angiogenesis, probably by limiting the availability of VEGF in tumor tissues. 相似文献
997.
Herniation through both Winslow’s foramen and a lesser omental defect: Report of a case 总被引:2,自引:0,他引:2
(Received for publication on May 6, 1999; accepted on Jan. 7, 2000) 相似文献
998.
Effects of hypothermia on intracranial pressure and brain edema formation: studies in a rat acute subdural hematoma model 总被引:10,自引:0,他引:10
Acute subdural hematoma (SDH) is the most common mass lesion in severe head injury, and brain ischemia is the leading pathophysiological mechanism in the development of secondary brain damage following SDH. Hypothermia has been employed as an effective neuroprotective procedure in clinical and laboratory studies on cerebral ischemic and contusional injuries. In the present study, we used a rat acute SDH model to assess the effect of hypothermia on the intracranial pressure (ICP) and also on the brain edema formation at 4 h after hematoma induction. Mild (34 degrees C) and moderate (32 degrees C) hypothermia did not significantly affect the ICP or cerebral perfusion pressure, but they were associated with a significant lower cortical brain edema formation beneath the hematoma (81.09 +/- 0.49%, p<0.05; and 80.88 +/- 0.17%, p<0.01) when compared with the normothermic control group (81.65 +/- 0.52%). This reduction in brain edema formation was comparable to the results of MK-801 treatment (80.95 +/- 0.35%, p<0.01). The present findings indicate that hypothermia represents a potent neuroprotective strategy. The possible protective mechanisms of hypothermic protection afforded in this rat acute SDH model are discussed. 相似文献
999.
K Fujimoto M Tagata M Nagao Y Suzuki H Iida F Kageyama A Yoshitomi S Hirose H Ikegaya H Okano 《呼吸と循環》1992,40(10):1019-1023
We report a case of middle-aged woman with myxedema heart who presented congestive heart failure due to myocardial damage caused by myxedema, and showed reversible and irreversible myocardial change proven by serial endomyocardial biopsy. She was admitted to our hospital because of facial, peripheral edema and dyspnea. On admission, chest X-P revealed severe cardiomegaly (CTR 70%) and bilateral pleural effusion. Electrocardiogram showed low voltage. Echocardiogram and chest CT revealed a large amount of pericardial effusion. No significant stenosis was observed on a coronary arteriogram. Laboratory data showed elevated TC, CPK, LDH values and immunological test indicated high titer of thyroid test and microsome test. Thyroid function test revealed primary hypothyroidism with low T3, low T4 and high TSH levels. Replacement therapy for hypothyroidism in addition to digitalis and diuretics++ has been started. Seven months after initial evaluation, this therapy has resulted in dramatic clinical improvement. Transvenous right ventricular endomyocardial biopsy demonstrated vacuolated degeneration on admission and improvement of vacuolated degeneration with a slight degree of fibrosis after therapy. This pathological finding suggests that myxedema heart is able to produce both reversible and irreversible myocardial damage. 相似文献
1000.
Wakabayashi Keiji; Nagao Minako; Tahira Tomoko; Yamaizumi Ziro; Katayama Masato; Marumo Shingo; Sugimura Takashi 《Mutagenesis》1986,1(6):423-426
Two indole compounds isolated from fresh Chinese cabbage wereshown to be mutagen precursors that yielded direct-acting mutagenson treatment with nitrite. They were identified as 4-methoxyindole-3-acetonitrileand 4-methoxy-indole-3-aldehyde. When these compounds were treatedwith 50 mM nitrite at pH 3.0 for 1 h at 37°C, 4-methoxyindole-3-acetonitrileinduced 31 800 and 10 000 revertants of Salmonella typhimuriumTA100 and TA98, respectively, per mg of mutagen precursor inthe absence of S9 mix, and 4-meth-oxyindole-3-aldehyde induced156 900 revertants of TA100 and 26 800 revertants of TA98 permg in the absence of S9 mix. 相似文献