全文获取类型
收费全文 | 18942篇 |
免费 | 879篇 |
国内免费 | 92篇 |
专业分类
耳鼻咽喉 | 297篇 |
儿科学 | 264篇 |
妇产科学 | 173篇 |
基础医学 | 2261篇 |
口腔科学 | 404篇 |
临床医学 | 1168篇 |
内科学 | 5027篇 |
皮肤病学 | 294篇 |
神经病学 | 1929篇 |
特种医学 | 655篇 |
外科学 | 2868篇 |
综合类 | 96篇 |
预防医学 | 764篇 |
眼科学 | 448篇 |
药学 | 1316篇 |
中国医学 | 55篇 |
肿瘤学 | 1894篇 |
出版年
2023年 | 83篇 |
2022年 | 172篇 |
2021年 | 285篇 |
2020年 | 154篇 |
2019年 | 222篇 |
2018年 | 286篇 |
2017年 | 222篇 |
2016年 | 263篇 |
2015年 | 282篇 |
2014年 | 397篇 |
2013年 | 513篇 |
2012年 | 813篇 |
2011年 | 921篇 |
2010年 | 489篇 |
2009年 | 431篇 |
2008年 | 871篇 |
2007年 | 957篇 |
2006年 | 935篇 |
2005年 | 999篇 |
2004年 | 949篇 |
2003年 | 872篇 |
2002年 | 877篇 |
2001年 | 739篇 |
2000年 | 788篇 |
1999年 | 660篇 |
1998年 | 263篇 |
1997年 | 230篇 |
1996年 | 204篇 |
1995年 | 159篇 |
1994年 | 142篇 |
1993年 | 143篇 |
1992年 | 411篇 |
1991年 | 394篇 |
1990年 | 350篇 |
1989年 | 391篇 |
1988年 | 357篇 |
1987年 | 303篇 |
1986年 | 274篇 |
1985年 | 278篇 |
1984年 | 206篇 |
1983年 | 175篇 |
1982年 | 93篇 |
1979年 | 146篇 |
1978年 | 113篇 |
1977年 | 79篇 |
1974年 | 90篇 |
1973年 | 89篇 |
1972年 | 90篇 |
1971年 | 78篇 |
1969年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Intraoperative monitoring of anorectal pressure was used in a case of sacral lipomeningocele accompanied by congenital dermal sinus to protect the physiological function of the anorectal sphincters. This monitoring system consists of a manometric anorectal balloon and neural electrical stimulation. The system was able to differentiate functioning neural structures from surrounding tissues during the operation. 相似文献
102.
Eight adult cats of either sex were studied. The minimal alveolar concentration (MAC) for sevoflurane in the cats was found to be 2.58 ± 0.30% (mean ± SD). The ratios of MAC values between sevoflurane and halothane, enflurane and isoflurane in cats were very similar to those ratios found in humans and dogs. This observation suggests that the results of this study are correct and allows us to estimate unknown MAC values for sevoflurane in other species using known MAC values for other anesthetic agents.(Doi M, Yunoki H, Ikeda K: The minimum alveolar concentration of sevoflurane in cats. J Anesth 2: 113–114, 1988) 相似文献
103.
U Ikeda F Ohkawa Y Seino K Yamamoto Y Hidaka T Kasahara T Kawai K Shimada 《Journal of molecular and cellular cardiology》1992,24(6):579-584
We have examined serum interleukin 6 (IL-6) levels in 12 patients with acute myocardial infarction (AMI). IL-6 levels became elevated in all patients, following the rise of serum creatine kinase (CK) activity. Peak IL-6 levels showed a good correlation with peak serum C-reactive protein (CRP) levels, while there was no direct relationship between peak IL-6 levels and peak CK activity. IL-6 mRNA was not detected in unstimulated "quiescent" rat cardiocytes cultured in serum-free medium, but its expression was induced by exposure of the cells to serum or ionomycin. These results show that IL-6 is synthesized in the myocardium and serum IL-6 levels become elevated in AMI, suggesting that IL-6 could affect the progression and/or healing processes of AMI. 相似文献
104.
Yoshihiro Katagiri Kazuhide Mabuchi Tadanori Itakura Kohji Naora Kikuo Iwamoto Yoshimasa Nozu Shun-ichi Hirai Nobumasa Ikeda Toshio Kawai 《Cancer chemotherapy and pharmacology》1989,24(4):238-242
Summary Physicochemical properties of two types of adriamycin preparation, suspensions and emulsions prepared for i.a. chemotherapy of hepatocellular cacinoma, were investigated. A suspension was prepared by dispersing adriamycin directly into the lipid contrast medium, Lipiodol, whereas an emulsion was obtained by emulsifying an aqueous solution of adriamycin into Lipiodol. The dispersibility of the drug in each preparation was examined microscopically. The chemical stability of and drug release from the preparation were determined by high-performance liquid chromatography and spectrophotometry, respectively. The suspension was then given to ten patients with primary hepatocellular carcinoma. The suspension maintained good dispersibility without coagulation of drug particles, whereas coalescence of aqueous droplets and the resultant phase separation occurred 4 h after preparation of the emulsion. Both preparations maintained the initial drug content for at least 1 week at room temperature. The release of adriamycin was more prolonged in the suspension than in the emulsion. After i.a. administration of the suspension, a selective accumulation of Lipiodol in the tumor and decrease in serum -fetoprotein (AFP) levels were found in most patients. A significant amount of adriamycin was still detected in hepatic speciments resected from two patients 1 and 2 months after treatment. These findings suggest that the adriamycin-Lipiodol suspension may be a useful preparation for targeting chemotherapy to hepatocellular carcinoma. 相似文献
105.
Kangouri K Miyoshi T Kawashima A Ikeda A Mizutani T Omura S Lian-Niang L Hong X 《Planta medica》1989,55(3):297-299
Neokadsuranic acid A, which is the first triterpenoid with the 14(13-->12) ABEO lanostane skeleton, was isolated from KADSURA HETEROCLITA together with (24 Z)-3-oxo-lanosta-8,24-dien-26-oic acid. The present paper deals with the isolation and structure elucidation of these two new compounds. 相似文献
106.
Fukushima M Morita M Ikeda K Nagayama S 《International journal of molecular medicine》2003,12(6):839-844
Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) has been suggested to be sensitivity-limiting factors of 5-fluorouracil therapy in cancer patients. We conducted a large-scale population study on the activity of TS and DPD in patients with various solid tumors. A total of 2590 clinically removed tumors, consisting of 1112 colon, 724 gastric, 520 breast, and 236 non-small cell lung cancers, were provided to measure TS and DPD activity. TS activity in the gastric, colon, and non-small cell lung cancers was significantly higher than in matched non-cancerous tissue (P<0.0002), but there was no difference in TS expression between tumor and non-cancerous tissue from breast cancer patients. Gastric, breast, and non-small cell lung cancers showed significantly higher DPD activity than their corresponding non-cancerous tissues, but colon cancers did not. There was no correlation between TS activity and DPD activity, and thus each enzyme was considered to be an independent sensitivity-limiting factor for 5-fluorouracil therapy. The median TS activity and median DPD activity in all specimens including gastric, colorectal, breast, and non-small cell lung cancers tested were 0.041 and 110.1 pmol/mg protein, respectively. We classified each of the type of carcinoma into 4 groups by using the median activity of TS and DPD as the cutoff values: a low TS/low DPD group, high TS/low DPD group, low TS/high DPD group, and high TS/high DPD group. About 50% of the gastric, 47% of the colon, 70% of the breast and 30% of the non-small cell lung cancers had high TS activity, and 60% of the gastric, 40% of the colon, 48% of the breast, and 87% of the lung cancers had high DPD activity. Moreover, breast cancer was characterized by high TS activity and lung cancer by high DPD activity as compared with gastric and colon cancers, and their high activity levels may influence to the effectiveness of 5-fluorouracil against cancers of these organs. The results for expression of TS and DPD in clinically dissected tumors would be useful to estimate the efficacy of 5-fluorouracil in the treatment of cancer patients. 相似文献
107.
Shimizu S Yamada N Sawada T Ikeda K Nakatani K Seki S Kaneda K Hirakawa K 《Pathology international》2000,50(12):953-959
To demonstrate ultrastructural events in the early phase of hepatic metastasis of human colon carcinoma, we intrasplenically injected a highly metastasizable, human colon carcinoma cell line LM-H3 (1 x 10(6) cells) into nude mice, and electron microscopically investigated the hepatic metastasis. At 24 h, tumor cells adhered to the endothelial wall of terminal portal venules and periportal sinusoids. At 48-72 h, after extravasation, they deeply invaded the hepatic cell plate and the interstitial tissue of the portal tract, in which they underwent proliferation and made the metastatic foci. Tumor cells were linked with each other or with surrounding hepatocytes by desmosomes. Desmosomes were maintained during the mitosis. When invading tumor cells were exposed to the bile canaliculi, they generated microvilli on the surface. Microvilli were also formed at the luminal surface of intracytoplasmic inclusions. In the interstitial tissue of the portal tract, tumor cells were closely associated with fibroblasts. However, no junctional specializations were seen between them. The present study demonstrated that human colon carcinoma cell line LM-H3 formed desmosomes with hepatocytes soon after invasion of the hepatic cell plate, suggesting the regulatory role of an interaction with hepatocytes in the growth of metastatic foci within the liver parenchyma. 相似文献
108.
A promoter variant of the ATP-binding cassette transporter A1 gene alters the HDL cholesterol level in the general Japanese population 总被引:3,自引:0,他引:3
Shioji K Nishioka J Naraba H Kokubo Y Mannami T Inamoto N Kamide K Takiuchi S Yoshii M Miwa Y Kawano Y Miyata T Miyazaki S Goto Y Nonogi H Tago N Iwai N 《Journal of human genetics》2004,49(3):141-147
To investigate the effects of polymorphisms in the ATP-binding cassette transporter A1 (ABCA1) gene on the high-density lipoprotein cholesterol (HDL-C) level and the incidence of myocardial infarction (MI), we performed association studies. Sequence analysis identified 14 polymorphisms in the promoter region of ABCA1. After considering linkage disequilibrium, three polymorphisms in the promoter region and 11 polymorphisms from the JSNP database were determined in 1,880 subjects recruited from the Suita Study, representing the general population in Japan. We evaluated the association between the ABCA1 genotype and HDL-C level adjusted not only for standard factors, but also for genetic factors including ApoA1 and ApoE genotypes. Of the 14 polymorphisms tested, the G(–273)C (P=0.0074), C(–297)T (P=0.0195), and IMS-JST071749
(P=0.0093) polymorphisms were significantly associated with the HDL-C level in the Suita population. We could reconfirm that the G(–273)C genotype was influential in another set of subjects (P=0.0310, n=743). However, the distribution of the ABCA1 G(–273)C
genotype in subjects with MI (n=598) was not different from that in the control population (n=801). These results indicate that ABCA1 G(–273)C
has a significant effect on the HDL-C level in the general Japanese population, but not on the incidence of MI. 相似文献
109.
110.
Association of the insertion/deletion polymorphism of the angiotensin I-converting enzyme gene in patients of migraine with aura 总被引:2,自引:0,他引:2
Kowa H Fusayasu E Ijiri T Ishizaki K Yasui K Nakaso K Kusumi M Takeshima T Nakashima K 《Neuroscience letters》2005,374(2):129-131
Recently, several angiotensin I-converting enzyme (ACE) inhibitors and an angiotensin II receptor blocker were demonstrated to have a clinically important prophylactic effect in migraine. ACE is one of the key enzymes in the rennin-angiotensin-aldosterone system, which modulates vascular tension and blood pressure. In humans, serum ACE levels are strongly genetically determined. Individuals who were homozygous for the deletion (D) allele showed increased ACE activity levels. To investigate the role of ACE polymorphism in headache, we analyzed the ACE insertion (I)/deletion (D) genotypes of 54 patients suffering from migraine with aura (MwA), 122 from migraine without aura, 78 from tension-type headache (TH), and 248 non-headache healthy controls. The ACE D allele were significantly more frequent in the MwA than controls (p<0.01). The incidence of the D/D genotype in MwA (25.9%) was significantly higher than that in controls (12.5%; p<0.01; odds ratio=5.26, 95% confidence interval: 1.69-16.34, adjusted for age and gender). No differences in the remaining groups were found. Our results support the conclusion that the D allele and the D/D genotype in the ACE gene is a genetic risk factor for Japanese MwA. There seems to be a possible relationship between ACE activity and the pathogenesis of migraine. 相似文献