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   373篇
  免费   14篇
  国内免费   1篇
儿科学   6篇
妇产科学   2篇
基础医学   30篇
口腔科学   8篇
临床医学   11篇
内科学   115篇
皮肤病学   1篇
神经病学   35篇
特种医学   11篇
外科学   48篇
综合类   3篇
预防医学   3篇
眼科学   2篇
药学   39篇
肿瘤学   74篇
  2022年   2篇
  2021年   5篇
  2020年   4篇
  2019年   3篇
  2018年   7篇
  2017年   11篇
  2016年   3篇
  2015年   5篇
  2014年   6篇
  2013年   9篇
  2012年   9篇
  2011年   15篇
  2010年   7篇
  2009年   11篇
  2008年   18篇
  2007年   22篇
  2006年   19篇
  2005年   11篇
  2004年   9篇
  2003年   28篇
  2002年   21篇
  2001年   18篇
  2000年   15篇
  1999年   18篇
  1997年   4篇
  1996年   4篇
  1995年   4篇
  1993年   3篇
  1992年   11篇
  1991年   10篇
  1990年   8篇
  1989年   8篇
  1988年   5篇
  1987年   6篇
  1986年   4篇
  1985年   7篇
  1984年   3篇
  1983年   5篇
  1981年   2篇
  1979年   1篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
  1972年   2篇
  1971年   2篇
  1970年   4篇
  1969年   3篇
  1968年   2篇
  1967年   2篇
  1966年   2篇
排序方式: 共有388条查询结果,搜索用时 531 毫秒
1.
Summary A novel antitumor compound, N--dimethylaminoethyl 9-carboxy-5-hydroxy-10-methoxybenzo[a]-phenazine-6-carboxamide sodium salt (NC-190) was evaluated for its antitumor activity in experimental murine tumor systems. In the initial studies with P388 leukemia (i.p.-i.p.), NC-190 led to an increase of >200% in life span (ILS), and 75% of the mice were alive on day 30, when the optimal dose (50 mg/kg, days 1–5) was given. Additionally, the compound had significant activities against i.p. inoculated mouse L1210 leukemia, B16 melanoma, M5076 reticulum cell sarcoma, sarcoma 180, mouse hepatoma MH134, and rat Yoshida sarcoma and Yoshida ascites hepatoma AH130. The optimal dose resulted in a >280% ILS with a 30-day survival of 50% in mice with L1210 leukemia (100 mg/kg, days 1–5), a 156% ILS in mice with B16 melanoma (50 mg/kg, days 1–5), a 98% ILS with a 90-day survival of 25% in mice with M5076 reticulum cell sarcoma (25 mg/kg, days 1, 5, 9, and 13), a >300% ILS with a 60-day survival of 50% in mice with sarcoma 180 (50 mg/kg, days 3–10), a 148% ILS with a 60-day survival of 25% in mice with MH134 (25 mg/kg, days 1–5), a 129% ILS with a 60-day survival of 12.5% in rats with Yoshida sarcoma (12.5 mg/kg, day 3–10), and a >161% ILS with a 60-day survival of 50% in rats with AH130 (6.3 mg/kg, days 3–10). In the experiments with s.c. inoculated tumors, NC-190 not only inhibited tumor growth, but also increased the life span of mice with Lewis lung carcinoma or B16 melanoma. The 60-day survivors accounted for 60% and 30% in mice with Lewis lung carcinoma and B16 melanoma, respectively. The compound significantly inhibited the spontaneous lung metastasis of Lewis lung carcinoma by more than 90% when eight daily i.v. injections were given. NC-190 was active by the i.p., s.c., and i.v. routes. Five consecutive daily i.p. doses (days 1–5) were more effective than a single dose (day 1), two doses (days 1 and 5), or three doses (days 1, 5, and 9). NC-190 warrants further study as a potential antineoplastic agent against human neoplasms, as it has a broad spectrum of antitumor activity and inhibits metastasis.Abbreviations ILS increase in life span - MST median survival time - MMC mitomycin C - ADM adriamycin - CPA cyclophosphamide - 5-FU 5-fluorouracil  相似文献   
2.
Usual interstitial pneumonia (UIP), or idiopathic pulmonary fibrosis, has been considered to be associated with a high risk for lung carcinoma. To investigate this well-known but still equivocal relationship, we reviewed the clinical features of UIP autopsy cases with or without lung carcinoma (n = 32 and 38, respectively), and compared the morphology and cell kinetics of metaplastic epithelia in the honeycombed areas (n = 11, each group). Thirty-two of 70 UIP autopsy cases showed lung carcinomas. Clinically, UIP with lung carcinoma showed a male predominance (P = 0.001), a higher rate of smoking history (P = 0.001) and a later onset of UIP (P = 0.02), compared with UIP without lung carcinoma. Most of the carcinomas were peripheral in origin (90%), and 65% were topographically associated with honeycombed areas or the border between honeycombing and non-fibrotic areas. Quantitative assessment of the metaplastic epithelia in the honeycombed areas revealed that squamous metaplasia, but not cuboidal cell metaplasia or bronchial cell metaplasia, occurred more frequently in UIP with lung carcinoma than in UIP without lung carcinoma (P = 0.02). There were no significant differences between the two groups with regard to the labeling indexes of Ki-67 and p53 in the metaplastic epithelia, including squamous metaplasia. The degree of atypical squamous metaplasia was not different between the two groups. The quantitative predominance of squamous metaplasia in the honeycombed areas may not be a precursor for lung carcinoma, but might reflect a constitutional susceptibility of UIP patients to develop a lung carcinoma.  相似文献   
3.
Morphological changes in the mouse sublingual gland parenchyma subjected to parasympathetic nerve block were investigated. Mice were subjected to unilateral resection of the chorda tympani, near its point of joining with the lingual nerve. After 1, 2, 3, 5, 10 or 20 weeks, the mice were killed and their sublingual glands were removed and processed for light and electron microscopy. Two weeks after resection, the space between the adjoining lobules of the glands on the treated side began to be expanded, and by 10 weeks were 10 times the size of the spaces in the glands of the untreated mice. Three weeks after resection, the lobule area decreased to about 72% of the area of glands in the untreated mice and the acinus area to about 52%. However, no significant difference was seen between the numbers of acini in each group. Electron microscopy showed that the glands on the treated side contained fewer secretory granules than the glands in the untreated mice, though there was no difference in size. Neither the lobules of the glands on the treated side nor those of the glands of the untreated mice contained many TUNEL-positive cells. These findings suggest that following parasympathetic nerve resection, mouse sublingual gland acinar cells undergo atrophy with a reduction size rather than cell death.  相似文献   
4.
Summary Subcutaneously (s.c.) administered apomorphine (0.0125–0.4 mg/kg) or physostigmine (0.025–0.4 mg/kg) to rats elicited yawning. The dose-response curves were bellshaped. The peak effects of apomorphine and physostigmine were observed with a dose of 0.1 mg/kg of each drug. Yawning elicited by apomorphine (0.1 mg/kg) or physostigmine (0.1 mg/kg) was reduced by intraperitoneally (i.p.) administered 5-hydroxytryptophan (5-HTP, 50–200 mg/kg, given 30 min before). Yawning elicited by apomorphine but not by physostigmine was enhanced by p-chlorophenylalanine (p-CPA, 25–400 mg/kg i.p., given 24 h before). Apomorphine elicited but not physostigmine-elicited yawning was enhanced by pretreatment with 5,7-dihydroxytryptamine (5,7-DHT, 8 g/rat, given 14 days before into the dorsal raphe). This treatment led to a 35% depletion of serotonin (5-HT) in the striatum. 5-HTP, p-CPA or 5,7-DHT given alone did not elicit yawning. Bilateral, intrastriatal microinjection of apomorphine (1.5 –50 g/site) but not physostigmine (5–50 g/site) elicited yawning. The dose-response curve was also bell-shaped. These results indicate that central serotonergic pathways play an important role in modulating drug-elicited yawning in rats. Send offprint requests to S. Okuyama at the above address  相似文献   
5.
PURPOSE: Squamous cell carcinoma (SCC) and adenocarcinoma of the lung are currently subject to similar treatment regimens despite distinct differences in histology and epidemiology. The aim of this study is to identify a molecular target with diagnostic and therapeutic values for SCC. EXPERIMENTAL DESIGN: Genes specifically up-regulated in SCC were explored through microarray analysis of 5 SCCs, 5 adenocarcinomas, 10 small cell lung carcinomas, 27 normal tissues, and 40 cancer cell lines. Clinical usefulness of these genes was subsequently examined mainly by immunohistochemical analysis. RESULTS: Seven genes, including aldo-keto reductase family 1, member B10 (AKR1B10), were identified as SCC-specific genes. AKR1B10 was further examined by immunohistochemical analysis of 101 non-small cell lung carcinomas (NSCLC) and its overexpression was observed in 27 of 32 (84.4%) SCCs and 19 of 65 (29.2%) adenocarcinomas. Multiple regression analysis showed that smoking was an independent variable responsible for AKR1B10 overexpression in NSCLCs (P < 0.01) and adenocarcinomas (P < 0.01). AKR1B10 staining was occasionally observed even in squamous metaplasia, a precancerous lesion of SCC. CONCLUSION: AKR1B10 was overexpressed in most cases with SCC, which is closely associated with smoking, and many adenocarcinoma cases of smokers. These results suggest that AKR1B10 is a potential diagnostic marker specific to smokers' NSCLCs and might be involved in tobacco-related carcinogenesis.  相似文献   
6.
OBJECT: Patients with subarachnoid hemorrhage (SAH) in whom angiography does not demonstrate diagnostic findings sometimes suffer recurrent disease and actually harbor undetected cerebral aneurysms. The management strategy for such cases remains controversial, but technological advances in spiral computerized tomography (CT) angiography are changing the picture. The purpose of this prospective study was to examine how spiral CT angiography can contribute to the detection of cerebral aneurysms that cannot be visualized on angiography. METHODS: In 134 consecutive patients with SAH, a prospective search for the source of bleeding was performed using digital subtraction (DS) and spiral CT angiography. In 21 patients in whom initial DS angiography yielded no diagnostic findings, spiral CT angiography was performed within 3 days. Patients in whom CT angiography provided no diagnostic results underwent second and third DS angiography sessions after approximately 2 weeks and 6 months, respectively. Six patients with perimesencephalic SAH were included in the 21 cases. Six of the other 15 patients had small cerebral aneurysms detectable by spiral CT angiography, five involving the anterior communicating artery and one the middle cerebral artery. Two patients in whom initial angiograms did not demonstrate diagnostic findings proved to have a ruptured dissecting aneurysm of the vertebral artery; in one case this was revealed at autopsy and in the other during the second DS angiography session. A third DS angiography session revealed no diagnostic results in 13 patients. CONCLUSIONS: Spiral CT angiography was useful in the detection of cerebral aneurysms in patients with SAH in whom angiography revealed no diagnostic findings. Anterior communicating artery aneurysms are generally well hidden in these types of SAH cases. A repeated angiography session was warranted in patients with nonperimesencephalic SAH and in whom initial angiography revealed no diagnostic findings, although a third session was thought to be superfluous.  相似文献   
7.
We assessed the effects of angiotensin-converting enzyme (ACE) inhibition on changes in the myocardial intracellular creatine kinase (CK) system in relation to left ventricular (LV) remodeling and function in heart failure after myocardial infarction (MI) in rats. We compared the findings at 4 weeks after MI to those at 12 weeks after MI. LV weight and chamber size were significantly increased and percent fractional shortening (%FS) was decreased in untreated MI rats compared with normal control animals both at 4 and 12 weeks after MI. Animals with MI and treated with the ACE inhibitor temocapril showed significantly reduced LV weight and chamber size and increased %FS compared with untreated MI rats at 12 weeks after MI, but not at 4 weeks after MI. At 4 weeks after MI, no significant changes were found in the total creatine and relative distribution of each CK isoenzyme in either the temocapril-treated or untreated animals with MI compared with the normal controls. In contrast, at 12 weeks after MI, untreated MI rats showed significant reductions in the total creatine and mitochondrial and MM-CK fractions and increases in the MB- and BB-CK fractions compared with the controls. The alterations in the mitochondrial and MB-CK fractions were significantly attenuated after 12 weeks of ACE inhibition. Thus, LV myocardial energy metabolism is progressively impaired and its alteration is not related to the magnitude of geometric changes and LV dysfunction after MI. Most of the beneficial effects of ACE inhibition were observed at 12 weeks after MI. Our results may provide an insight into the therapeutic strategy of ACE inhibition in chronic heart failure after MI.  相似文献   
8.
We measured serum thrombopoietin (TPO) in chronic hepatitis C treated with interferon (IFN). The platelet count before the therapy was 161.9 ×109 ± 64.1 × 109/l, which decreased to 116.3 × 109 ±  48.4 × 109/l 1 week after IFN therapy ( P  <0.01). On the other hand, serum TPO increased from 1.96 ± 0.60 fmol/ml to 2.68 ± 0.69 fmol/ml ( P  < 0.02). Contrary to a recent report that serum TPO was not altered in liver cirrhosis, these data indicate that serum TPO was increased in chronic hepatitis C in response to thrombocytopenia by IFN therapy.  相似文献   
9.
The purpose of this study was to investigate the cellular distribution of carnitine and its acyl derivatives in the normal and ischemic myocardium, and the effects of exogenous 1-carnitine on this distribution and mitochondrial function in the ischemic dog heart. Under non-ischemic conditions, about 93% of the total cellular carnitine was located in the cytosolic compartment and 6.5% in the mitochondrial compartment. Sixty minutes of ischemia induced a decrease in the cytosolic free carnitine content, but caused the accumulation of long-chain acylcarnitine in the cytosolic and mitochondrial compartments. Treatment with 1-carnitine (30 or 100 mg/kg, i.v.) inhibited the mitochondrial accumulation of long-chain acylcarnitine. Free fatty acid (FFA) metabolism in the mitochondria differs from that in the cytosol. So, it is necessary to investigate the changes in FFA metabolism in both of these cellular compartments. Our results suggest that 1-carnitine has a protective effect on the ischemic heart by selectively reducing mitochondrial accumulation of long-chain acylcarnitine.  相似文献   
10.
Abstract: We present a case of severe exacerbation of hepatitis after short‐term corticosteroid therapy for chronic inflammatory demyelinating polyneuropathy (CIPD) with “latent” chronic hepatitis B showing no HBV‐related antigens and antibodies. After corticosteroid pulse therapy for CIPD, the patient had severe exacerbation of hepatitis twice. Although she did not show any hepatitis B virus (HBV)‐related antigens or antibodies, sequences of HBV were detected in serum and liver by a nested polymerase chain reaction. A sequence analysis of HBV at the second exacerbation showed that the G‐to‐A point mutation at nucleotide 1896 that converted codon 28 from tryptophan (TGG) to a stop codon (TAG) in the precore region resulted in amino acid change, which has been frequently observed in fulminant hepatitis and severe hepatitis in Japan.  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