首页 | 官方网站   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   830篇
  免费   59篇
  国内免费   2篇
医药卫生   891篇
  2022年   13篇
  2021年   28篇
  2020年   15篇
  2019年   20篇
  2018年   32篇
  2017年   23篇
  2016年   18篇
  2015年   18篇
  2014年   19篇
  2013年   29篇
  2012年   39篇
  2011年   52篇
  2010年   20篇
  2009年   18篇
  2008年   32篇
  2007年   49篇
  2006年   42篇
  2005年   47篇
  2004年   54篇
  2003年   36篇
  2002年   52篇
  2001年   27篇
  2000年   27篇
  1999年   23篇
  1998年   7篇
  1997年   9篇
  1996年   9篇
  1995年   6篇
  1994年   9篇
  1993年   4篇
  1992年   6篇
  1991年   6篇
  1990年   10篇
  1989年   9篇
  1988年   8篇
  1987年   9篇
  1986年   4篇
  1985年   7篇
  1984年   3篇
  1983年   6篇
  1982年   4篇
  1980年   5篇
  1978年   5篇
  1972年   3篇
  1971年   3篇
  1970年   3篇
  1969年   4篇
  1968年   4篇
  1967年   3篇
  1966年   3篇
排序方式: 共有891条查询结果,搜索用时 15 毫秒
101.
The dissolving mixture is administered through a choledochal drain to treat postoperatively retained cholesterol gallstones. It is preparted by mixing 97.0 parts of d-limonene with 2.1 parts of polysorbate 80 and 0.9 part of sorbitan monooleate, a mixture of which may easily reach the surface of the gallstones which are wetted by bile. The d-limonene preparation was found to be safe both in laboratory experiments and clinical trials. Before applying the preparation, the usual choledochal drain must be replaced with a recently developed catheter made from epichlorohydrine rubber, which is chemically resistant to the preparation. Three cases of retained gallstones are described where the preparation was successfully used. In the fourth case treatment with the preparation was tried in lieu of surgery but was not successful due to other complications. However, some dissolution of retained stones was observed. There were no postoperative complaints in the long-term follow-up of some cases for more than 2 yr after treatment with the preparation. This procedure promises to be of value because retained cholesterol stones may be dissolved without the necessity of further surgery.  相似文献   
102.
Polystyrene-supported 1,8-diazabicyclo[5.4.0]undec-7-ene (PDBU) was prepared by the reaction of lithiated 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with chloromethylated or ω-bromoalkylated polystyrene resins. PDBU is effective as reagent for dehydrobromination and esterification. The reactivity of PDBU in dehydrobromination is lower than that of DBU. In the case of esterification, PDBU with 19% ring substitution exhibits almost the same reactivity as DBU. PDBU, regenerated from the hydrobromide salt, can be re-used without decrease in reactivity.  相似文献   
103.
104.
In the course of our studies on naturally occurring cardioactive agents, we investigated the effects of water and methanol extracts of a Chinese crude drug “Huajiao” the dried fruit of Zanthoxylum bungeanum, on the spontaneous beating rate (BR) of embryonic mouse myocardial cell sheets in culture. Both extracts significantly increased the BR. Through bioassay directed fractionation of the extracts, hydroxy-β-sanshool (1b), xanthoxylin (2) and two quercetin glycosides, hyperin (4) and quercitrin (6), were found to increase the BR in a standard medium (2.1 mM Ca2+). In a low Ca2+ medium (0.5 mM Ca2+), these compounds suppressed the decrease of BR, which was induced by low Ca2+. Of 16 flavonoids related in structure with hyperin (4) and quercitrin (6), quercetin, isoquercitrin, rutin, myricetin and myricitrin also increased the BR in the standard medium, while kaempferol and luteorin decreased the BR in the standard medium. When compared with control, hydroxy-β-sanshool (1b) and xanthoxylin (2) stimulated 13–15 fold calcium uptake of the cultured myocardial cells, which might have caused the positive chronotropic effect. Hyperin (4) and quercitrin (6) did not affect calcium uptake of the myocardial cells, Na+–K+ ATPase activity or Ca2+-ATPase activity of sarcoplasmic reticulum.  相似文献   
105.
Malignant pleural mesothelioma (MPM) is closely related to exposure to asbestos, and a rapid increase in the number of MPM patients in Japan is estimated in the years 2010-2050. The purpose of the present study was to establish a clinically relevant animal model that shows human patient-like progression of MPM. Here, we demonstrate that a human MPM cell line (EHMES-10) inoculated orthotopically (thoracic cavity) into severe combined immunodeficiency (SCID) mice produces highly vascularized thoracic tumors with pleural dissemination and bloody pleural effusions by 5 weeks, suggesting a patient-like progression of this cell line after orthotopic inoculation. EHMES-10 cells overexpressed vascular endothelial growth factor (VEGF), a molecule responsible for malignant effusions, and its receptor. Treatment with cisplatin, but not gemcitabine, significantly inhibited the production of pleural effusions, but it was not effective for thoracic tumors, consistent with chemotherapy refractory characteristics of MPM in patients. Our patient-like orthotopic model using EHMES-10 cells overexpressing VEGF and its receptor may be useful for examining the molecular pathogenesis of MPM and may contribute to the development of novel treatment strategies for MPM.  相似文献   
106.
A 25-year-old male who had no significant medical history presented abrupt onset of high-grade fever and chills without noticeable trigger. The patient sought for medical attention for subsequently developed dyspnea and chest pain. Radiological examinations revealed bilateral lung peripheral multiple opacities, some of which were cavitating, suggesting of septic pulmonary emboli (SPE). Isolation of Staphylococcus aureus in blood and sputum culture confirmed the diagnosis. Extensive examinations disclosed neither underlying immunocompromising conditions nor infectious foci, which are usually notable in patients with SPE. The present patient illustrates that there are patients with SPE in whom underlying conditions or infectious foci are difficult to determine, and that suspicion of the disease based on characteristic radiological findings is critical for appropriate management in those patients.  相似文献   
107.
Studies on adenosine 3',5'-phosphate in rabbit cerebral cortex   总被引:24,自引:0,他引:24  
  相似文献   
108.
Propionic acidemia is a rare autosomal recessive disorder affecting the catabolism of branched-chain amino acids because of a genetic defect in PCC. Despite the improvements in medical treatment with protein restriction, sufficient caloric intake, supplementation of l-carnitine, and metronidazole, patients with the severe form of propionic acidemia have life-threatening metabolic acidosis, hyperammonemia, and cardiomyopathy, which results in serious neurologic sequelae and sometimes death. This study retrospectively reviewed three children with neonatal-onset propionic acidemia who received LDLT. Between November 2005 and December 2010, 148 children underwent LDLT, with an overall patient survival of 90.5%, in our center. Three patients were indicated for transplantation because of propionic acidemia. All recipients achieved a resolution of metabolic derangement and better quality of life with protein restriction and medication, although urine methylcitrate and serum propionylcarnitine levels did not decrease markedly. LT can reduce the magnitude of progressive cardiac/neurologic disability as a result of poor metabolic control. Further evaluation is therefore required to determine the long-term suitability of this treatment modality.  相似文献   
109.
DH is a rare complication following LT. This report presents three cases of right-sided DH after LT using a left-sided graft. All of the patients were younger than one yr of age, and they were critically ill owing to their original disease, characterized by biliary atresia, progressive familiar intrahepatic cholestasis, and acute liver failure. DH occurred with sudden onset within three months after LT. All of the cases were promptly diagnosed and treated. A literature review of 24 cases of DH identified four factors associated with DH: left-sided graft, right-sided DH, relatively delayed onset of DH, and age-specific chief complaint. DH following LT should be considered as a potential surgical complication when a left-sided graft is used, especially in small infants with coagulopathy and malnutrition.  相似文献   
110.
Classical serine proteases use the conserved Ser/His/Asp catalytic triad to hydrolyze substrates. Here, we show that longistatin, a salivary gland protein with two EF-hand domains from the vector tick Haemaphysalis longicornis, does not have the conserved catalytic triad, but still functions as a serine protease. Longistatin was synthesized in and secreted from the salivary glands of ticks, and is injected into host tissues during the acquisition of blood-meals. Longistatin hydrolyzed fibrinogen, an essential plasma protein in the coagulation cascade, and activated plasminogen, into its active form plasmin, a serine protease that dissolves fibrin clots. Longistatin efficiently hydrolyzed several serine protease-specific substrates showing its specificity to the amide bond of Arg. Longistatin did not hydrolyze synthetic substrates specific for other groups of proteases. The enzyme was active at a wide range of temperatures and pHs, with the optimum at 37°C and pH 7. Its activity was efficiently inhibited by various serine protease inhibitors such as phenylmethanesulfonyl fluoride (PMSF), aprotinin, antipain, and leupeptin with the estimated IC(50) of 278.57 μM, 0.35 μM, 41.56 μM and 198.86 μM, respectively. In addition, longistatin was also potently inhibited by Zinc (Zn(2+)) in a concentration-dependent manner with an IC(50) value of 275 μM, and the inhibitory effect of Zn(2+) was revived by ethylenediaminetetra acetic acid (EDTA). Immunization studies revealed that longistatin sharply induced high levels of protective IgG antibodies against ticks. Immunization with longistatin reduced repletion of ticks by about 54%, post engorgement body weight by >11% and molting of nymphs by approximately 34%; thus, the vaccination trial was approximately 73% effective against tick infestation. Taken together, our results suggest that longistatin is a new potent atypical serine protease, and may be an interesting candidate for the development of anti-tick vaccines.  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-23

京公网安备 11010802026262号