全文获取类型
收费全文 | 5178篇 |
免费 | 215篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 126篇 |
妇产科学 | 73篇 |
基础医学 | 712篇 |
口腔科学 | 106篇 |
临床医学 | 308篇 |
内科学 | 1052篇 |
皮肤病学 | 68篇 |
神经病学 | 362篇 |
特种医学 | 155篇 |
外科学 | 1006篇 |
综合类 | 32篇 |
预防医学 | 181篇 |
眼科学 | 131篇 |
药学 | 430篇 |
中国医学 | 13篇 |
肿瘤学 | 543篇 |
出版年
2023年 | 17篇 |
2022年 | 57篇 |
2021年 | 83篇 |
2020年 | 47篇 |
2019年 | 62篇 |
2018年 | 78篇 |
2017年 | 76篇 |
2016年 | 68篇 |
2015年 | 87篇 |
2014年 | 109篇 |
2013年 | 174篇 |
2012年 | 234篇 |
2011年 | 298篇 |
2010年 | 148篇 |
2009年 | 147篇 |
2008年 | 219篇 |
2007年 | 274篇 |
2006年 | 287篇 |
2005年 | 324篇 |
2004年 | 304篇 |
2003年 | 311篇 |
2002年 | 292篇 |
2001年 | 153篇 |
2000年 | 122篇 |
1999年 | 126篇 |
1998年 | 82篇 |
1997年 | 72篇 |
1996年 | 75篇 |
1995年 | 54篇 |
1994年 | 49篇 |
1993年 | 30篇 |
1992年 | 93篇 |
1991年 | 100篇 |
1990年 | 80篇 |
1989年 | 98篇 |
1988年 | 69篇 |
1987年 | 75篇 |
1986年 | 52篇 |
1985年 | 66篇 |
1984年 | 32篇 |
1983年 | 33篇 |
1982年 | 15篇 |
1981年 | 18篇 |
1980年 | 19篇 |
1979年 | 22篇 |
1978年 | 24篇 |
1977年 | 21篇 |
1973年 | 16篇 |
1970年 | 15篇 |
1968年 | 14篇 |
排序方式: 共有5415条查询结果,搜索用时 15 毫秒
1.
Shin-ichi Iwata Hirofumi Morioka Atsuro Miyata 《Nihon shinkei seishin yakurigaku zasshi》2006,26(2):107-109
Antipsychotic drugs are classified as typical and atypical based on extrapyramidal effects. However, since the frontal cortex is one of the most important regions for antipsychotic actions, this study attempted to classify antipsychotic drugs based on gene expression in the frontal cortex. Chlorpromazine and thioridazine were selected as typical antipsychotics, and olanzapine and quetiapine as atypical antipsychotics. Since these drugs have similar chemical structures, the effect of the basic structure on gene expression can be eliminated. Cluster analysis of microarray experiments separated 4-drug-administered mice into chlorpromazine-quetiapine and thioridazine-olanzapine groups. This classification scheme is different from that which is based on criteria currently used to group the typical and atypical drugs and suggests that antipsychotic drugs can be further separated into multiple groups. 相似文献
2.
Effects of a newly introduced polyoxyethylene-modified superoxide dismutase (SOD-POE) on reperfusion induced arrhythmias were examined in the pentobarbital anesthetized rat. Reperfusion induced arrhythmias were elicited by occlusion of the left anterior descending coronary artery (LAD) for 15 min and subsequent release. The LAD occlusion was performed by compressing the artery using a suction cup of 2 mm in diameter placed on the LAD to which negative pressure was applied. The LAD occlusion and release was repeated at an interval of 30 min. SOD-POE or human SOD (h-SOD) (1000 U/kg) was injected intravenously 15 min prior to the occlusion at the second trial of the occlusion. In the control group, various types of arrhythmias including ventricular fibrillation (Vf), ventricular tachycardia (VT), premature ventricular contraction (PVC) and premature atrial contraction (PAC) were elicited immediately after release of the occlusion. In the SOD-POE-treated group, Vf and VT were completely prevented and the numbers of PVC and PAC significantly decreased, while pretreatment with h-SOD did not prevent the occurrence of reperfusion induced arrhythmias. The protective effects of SOD-POE lasted for more than 90-120 min. The plasma half life for SOD-POE was 10.8 hr, while that for h-SOD was 8.6 min. Results indicate that intravenous administration of SOD-POE would provide a new means of preventing reperfusion induced arrhythmias occurring in clinical situations. 相似文献
3.
4.
Moussa Ndong Machiko Kazami Tsukasa Suzuki Mariko Uehara Shin-ichi Katsumata Hirohumi Inoue Ken-Ichi Kobayashi Tadahiro Tadokoro Kazuharu Suzuki Yuji Yamamoto 《Nutrition Research》2009,29(9):640-647
Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity. 相似文献
5.
T Takatorige K Tatara K Kuroda N Nakanishi C Nishigaki E Okamoto N Nishi Y Nakagawa C Rin F Shinsho 《[Nihon kōshū eisei zasshi] Japanese journal of public health》1990,37(4):255-262
This study was done to identify factors affecting present hospitalization versus home care in 4,578 elderly subjects representing 87.1% of the elderly population living in S. city near Osaka. Subjects or their families were asked by interviews regarding the age of the subjects, the kind of persons living together in the family unit, the kind of housing, the number of rooms in the family dwelling, and health conditions. Subjects were also asked whether he or she could walk unassisted and whether home care would be preferred in case of an illness. Among the 153 hospitalized subjects, ability to walk, age, and the number of rooms were all significant factors, in decreasing order. Among the 1,193 persons who preferred home care in case of an illness, the number of rooms, age, ability to walk, and the size of the family unit were all significant factors, in decreasing order. Among subjects who could not walk unassisted, the number of rooms was the main factor determining their admission and not preferring home care if their condition worsened. Thus, although the ability to walk is the major factor among the factors we investigated, housing conditions are also important if home care is to be possible. 相似文献
6.
Masafumi Fujimoto Tuneaki Sakata Yuji Tsuruta Shoji Iwagami Hiroshi Teraoka Shin-ichi Mihara Yonetaka Fukiishi Misao Ide 《Biochemical pharmacology》1990,40(12):2661-2670
Bradykinin-stimulated prostacyclin synthesis in porcine aortic endothelial cells was enhanced by pretreatment of the cells with pertussis toxin or islet-activating protein (IAP) for 5 hr or longer. Although ADP-ribosylation of a protein with a molecular weight of 41–42 kD in the cell membranes was completed by 3 hr after the addition of IAP into the incubation medium, there was good correlation between enhancement of bradykinin-induced prostacyclin synthesis and ADP-ribosylation of the IAP substrate over a wide range of IAP concentrations. Furthermore, even if IAP was removed from the incubation medium at 3 hr, bradykinin-induced prostaglandin synthesis at 24 hr was still potentiated. Cycloheximide and actinomycin D enhanced bradykinin-induced prostacyclin synthesis and apparently blocked the effect of IAP. Since this result suggested the involvement of an inhibitor protein(s) of prostacyclin synthesis in the IAP effect, we studied the effect of IAP on the level of lipocortin I which is known to inhibit phospholipase A2. Western and Northern blot analyses revealed that IAP decreased the amounts of protein and mRNA of lipocortin I. These results suggest that the enhancement of bradykinin-induced prostacyclin synthesis by IAP is associated with a decrease in the level of lipocortin I. 相似文献
7.
Eiji Takeuchi Yuji Nimura Shin-ichi Mizuno Hideaki Suzuki Shinsuke Iyomasa Masaki Terasaki Hiroshi Kuriki Keiko Tamiya-Koizumi Shonen Yoshida 《Journal of Hepato-Biliary-Pancreatic Surgery》1997,4(3):254-262
Hepatocyte regeneration has been widely investigated, with the mitotic index and the incorporation of [3H]thymidine being used as regeneration markers. We focused on the induction of DNA replication enzymes, particularly DNA polymerases
(pol) α, δ, and ε. Using rat models, we have shown that the activity of pol α in crude liver extract well represents the regenerating
capacity of hepatocytes. Using pol α as an indicator, we analyzed liver regeneration in rat models under various conditions:
obstructive jaundice, external or internal biliary drainage, and the obstruction of portal vein branches. It has been revealed
that the ligation of the common bile duct alone induces a certain amount of hepatocyte proliferation. It was striking that
external biliary drainage suppressed regeneration capacity in cholestatic rat liver after partial hepatectomy. The strong
regeneration in nonligated lobes induced by portal branch ligation was similar to the liver regeneration seen after partial
hepatectomy with respect to the induction of DNA polymerases. Taken together, the aspects of DNA replication, particularly
the induction of DNA polymerases, may contribute to shedding new light on the regeneration of human liver.
This work was supported in part by a Grant-in-Aid for General Scientific Research and for Cancer Research from the Ministry
of Education, Science and Culture, Japan, and by grants from the Uehara Memorial Foundation 相似文献
8.
Electron-microscopic and immunohistochemical study of beta-2-microglobulin-related amyloidosis. 总被引:1,自引:0,他引:1
beta 2-Microglobulin (beta 2-MG)-related amyloidosis has been reported as a complication in long-term hemodialysis patients. We observed beta 2-MG amyloid deposits in synovial sheaths, bone cysts and gastric mucosa. They showed unique ultrastructural features, that is bundles or nodules consisting of curved or linear amyloid fibrils, associated with various cell reactions. The electron-microscopic histochemical study showed that they strongly stained with periodic acid-silver methenamine stain. A similar phenomenon was noticed in the spicules or bundles of amyloid fibrils in primary and secondary renal amyloidosis. With the cationic reagent toluidine blue 0, proteoglycan-like structures were observed around amyloid bundles and nodules, but not on each fibrils. Based on these results, we postulate that there is a close relationship between ultrastructural features and histochemical characteristics in beta 2-MG amyloid fibrils. 相似文献
9.
The utilization of radical operation in gastric cancer cases has led to the development of various operation techniques. With the improvement in perioperative management it can be said that age no longer is a restriction. A study of gastric cancer prognosis indicates an upward trend in survival since 1960 along with the increased detection of early cancer. This suggests the most importance of early detection in increasing the therapeutic results obtained in cases of gastric cancer. In cases with advanced cancer, 5-year survival rate of 44.7 per cent was attained through such aggressive actions as extended dissection of lymph nodes and combined resection of surrounding organs with evaluation of the macroscopic classification of the cancer. 相似文献
10.
Attenuation of lung injury in allograft rejection using NF-kappaB decoy transfection-novel strategy for use in lung transplantation. 总被引:5,自引:0,他引:5