全文获取类型
收费全文 | 7639篇 |
免费 | 339篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 182篇 |
儿科学 | 209篇 |
妇产科学 | 284篇 |
基础医学 | 853篇 |
口腔科学 | 70篇 |
临床医学 | 605篇 |
内科学 | 2435篇 |
皮肤病学 | 56篇 |
神经病学 | 563篇 |
特种医学 | 286篇 |
外科学 | 801篇 |
综合类 | 45篇 |
一般理论 | 1篇 |
预防医学 | 483篇 |
眼科学 | 123篇 |
药学 | 635篇 |
中国医学 | 3篇 |
肿瘤学 | 384篇 |
出版年
2023年 | 50篇 |
2022年 | 259篇 |
2021年 | 455篇 |
2020年 | 123篇 |
2019年 | 213篇 |
2018年 | 254篇 |
2017年 | 174篇 |
2016年 | 175篇 |
2015年 | 221篇 |
2014年 | 272篇 |
2013年 | 358篇 |
2012年 | 599篇 |
2011年 | 579篇 |
2010年 | 324篇 |
2009年 | 214篇 |
2008年 | 378篇 |
2007年 | 449篇 |
2006年 | 493篇 |
2005年 | 436篇 |
2004年 | 456篇 |
2003年 | 394篇 |
2002年 | 336篇 |
2001年 | 61篇 |
2000年 | 61篇 |
1999年 | 67篇 |
1998年 | 31篇 |
1997年 | 25篇 |
1996年 | 17篇 |
1995年 | 24篇 |
1994年 | 16篇 |
1993年 | 20篇 |
1992年 | 32篇 |
1991年 | 39篇 |
1990年 | 32篇 |
1989年 | 39篇 |
1988年 | 30篇 |
1987年 | 22篇 |
1986年 | 29篇 |
1985年 | 26篇 |
1984年 | 25篇 |
1983年 | 23篇 |
1982年 | 14篇 |
1981年 | 12篇 |
1980年 | 16篇 |
1979年 | 27篇 |
1978年 | 10篇 |
1976年 | 11篇 |
1975年 | 10篇 |
1973年 | 13篇 |
1972年 | 20篇 |
排序方式: 共有8018条查询结果,搜索用时 0 毫秒
31.
Value of the intraoperative assessment of the depth of myometrial invasion in endometrial carcinoma 总被引:1,自引:0,他引:1
Obrzut B Obrzut M Skret-Magierło J Skret A Ulman D Król P Zmuda M 《Ginekologia polska》2008,79(6):404-409
OBJECTIVES: The aim of the study was to evaluate the value of intraoperative assessment of depth of myometrial invasion in patients with FIGO stage I of the endometrial carcinoma. MATERIAL AND METHODS: A total number of 112 patients with FIGO stage I of the endometrial carcinoma undergoing surgery were enrolled in the study. All patients had undergone intraoperative assessment of the depth of myometrial invasion performed by a surgeon. The depth was determined as more or less than 50% of myometrial thickness according to FIGO classification. Gross visual estimation of the depth of myometrial invasion at the time of the operation was compared with the final histopathological report. Sensitivity, specificity and positive and negative predictive values of the method were determined by means of statistical analyses. RESULTS: The depth of the myometrial invasion was accurately determined by the surgeon in 82.1% of cases. Sensitivity and specificity were 68% and 82.1%, respectively. The accurate prediction rate of the myometrial invasion in the group of patients with well differentiated (G1) endometrial carcinoma was higher (88.4%) than in group with moderately and low differentiated tumour (78.3%). CONCLUSIONS: The accuracy of macroscopic evaluation of myometrial invasion is high and reaches up to 82.1%. The accurate determination rate increases if the differentiation of tumour is higher. 相似文献
32.
Thrombotic thrombocytopenic purpura (TTP) is characterized by microangiopathic hemolytic anemia and thrombocytopenia, accompanied by microvascular thrombosis that causes variable degrees of tissue ischemia and infarction. About 10-20% of TTP cases are associated with the pregnancy. Preterm delivery and intrauterine fetal death are frequent pregnancy complications of TTP. The following paper presents the case of a 32-year-old woman with TTP relapse at 10 weeks of her second pregnancy. Despite regular fresh frozen plasma transfusions, intrauterine fetal death occurred at 21 weeks of gestation. Current views on TTP management during pregnancy have been presented in the article as well. 相似文献
33.
Magnowski P Medrek K Magnowska M Stawicka M Kedzia H Górski B Lubiński J Spaczyński M 《Ginekologia polska》2008,79(8):544-549
OBJECTIVE: There is an increasing evidence that genetic factors play a role in the etiology of malignant tumors. Mutations of BRCA1 and BRCA2 genes are responsible for an increased risk of ovarian cancer. The role of mutations in NOD2 gene in this type of neoplasm is still under investigation. THE AIM: The aim of this study was to determine: 1. incidence of NOD 2 3020insC constitutional mutation in a group of consecutive women with ovarian cancer, 2. risk of developing ovarian cancer in patients with NOD2 gene mutation, 3. clinical and pathological features of ovarian cancer in NOD2 gene mutation carriers. PATIENTS AND METHODS: Clinical and pathological data were collected from 257 non-selected patients with primary epithelial ovarian cancer. The researches identified NOD2 3020insC gene mutation. On the basis of patient source documentation we obtained the data concerning the age of patients at diagnosis, histopathological recognition, FIGO stage and morphological grade G. RESULTS: 19 out of 257 women were identified with germ-line 3020insC mutation of NOD2 gene (7.39%). An increased risk of ovarian cancer in NOD2 mutation carriers was not revealed (OR=1.01; p=0.928; 95% Cl=0.61-1.66). The mean age at diagnosis of patients with NOD2 mutation was 54.8 (SD=9.9), while for non-carriers it was 53.2 (SD=10.2). The difference between these frequencies was statistically irrelevant (p=0.550). Clinical and pathological profile of ovarian cancer was made. We assessed the following features: age at disease onset, histopathology, FIGO stage and morphological grade G. For NOD2 mutation carriers no statistically significant features of ovarian cancer were revealed. CONCLUSION: 1. Despite high frequency of constitutional mutations occurrence in NOD2 gene in women with ovarian cancer, genetic testing seem not to be justified in all women diagnosed with this disease. 2. Due to a lack of increased risk of ovarian cancer in NOD2 gene mutation carriers, proceedings for them may not differ from recommendations for general population. 3. It is difficult to determine characteristic clinical and pathological features of ovarian cancer for NOD2 gene mutation carriers. 相似文献
34.
35.
Kaczmarek P Respondek-Liberska M Borowski D Wielgoś M Czuba B Oszukowski P 《Ginekologia polska》2007,78(11):861-864
OBJECTIVES: to confirm that fetal echocardiography is indeed possible in late first trimester and that it improves the standard of the so-called "genetic" ultrasound scan. MATERIAL AND METHODS: Early echocardiography was performed in 75 fetuses from high and low risk pregnancies. All fetuses underwent echocardiography examination in 18-22 weeks of gestation and established follow up. RESULTS: The most suitable method of visualization seems to be transabdominal examination, between 13.0-13.6 weeks of gestation, an transvaginal one, between 12.0-12.6 weeks of gestation, with 90% effectiveness. In researched group of 75 fetuses (with established follow up) there were four heart defects (5.3%). Three of them were diagnosed before 14th week of gestation. One case (tetralogy of Fallot) was overlooked. There were two false positive diagnosis verified at 20th week of gestation. CONCLUSIONS: Early echocardiography, especially between 12.0-13.6 weeks of gestation, is a possible and valuable method of diagnosis. Reference evaluation should be performed between 18 and 22 weeks of gestation. In cases with suspected anomalies karyotyping is recommended. Congenital heart disease diagnosed at late first trimester should be treated as the next potential marker of genetic disorder. 相似文献
36.
Tomasz Skrzekut Andrzej Piotrowicz Piotr Noga Maciej Wdrychowicz Adam W. Bydaek 《Materials》2022,15(11)
Recovery of zinc and manganese from scrapped alkaline batteries were carried out in the following way: leaching in H2SO4 and selective precipitation of zinc and manganese by alkalization/neutralization. As a result of non-selective leaching, 95.6–99.7% Zn was leached and 83.7–99.3% Mn was leached. A critical technological parameter is the liquid/solid treatment (l/s) ratio, which should be at least 20 mL∙g−1. Selective leaching, which allows the leaching of zinc only, takes place with a leaching yield of 84.8–98.5% Zn, with minimal manganese co-leaching, 0.7–12.3%. The optimal H2SO4 concentration is 0.25 mol∙L−1. Precipitation of zinc and manganese from the solution after non-selective leaching, with the use of NaOH at pH = 13, and then with H2SO4 to pH = 9, turned out to be ineffective: the manganese concentrate contained 19.9 wt.% Zn and zinc concentrate, and 21.46 wt.% Mn. Better selectivity results were obtained if zinc was precipitated from the solution after selective leaching: at pH = 6.5, 90% of Zn precipitated, and only 2% manganese. Moreover, the obtained concentrate contained over 90% of ZnO. The precipitation of zinc with sodium phosphate and sodium carbonate is non-selective, despite its relatively high efficiency: up to 93.70% of Zn and 4.48–93.18% of Mn and up to 95.22% of Zn and 19.55–99.71% Mn, respectively for Na3PO4 and Na2CO3. Recovered zinc and manganese compounds could have commercial values with suitable refining processes. 相似文献
37.
Wiktor Harmatys Piotr Gska Adam Gska Maciej Gruza Micha Jedynak Konrad Kobiela Michael Marxer 《Materials》2022,15(12)
Multisensor CMMs are systems with an established position on the market, but their popularity still grows, as they provide access to the advantages offered by tactile and contactless measurement methods. Yet there are still questions of the comparability of results obtained using the optical and tactile operation modes of multisensor system. This phenomenon can be assessed by measuring appropriate gauges, most often reference rings or spheres. Due to the completely different nature of probing processes for tactile and contactless measurements, the material from which reference object is made may significantly affect measurement results. In order to assess the influence of this factor on measurement accuracy, three reference spheres made from different materials were measured on optical multisensor CMMs. Measurements involved tactile measurements as well as optical measurements made using different probing systems: a video probe and white light sensor. Results obtained from performed experiments show large differences depending on the material used for spherical standard production. On the basis of obtained results, it can be stated that the best material for a reference object that can be used for comparability tests of tactile and optical measurements is a composite of alumina with at least one oxidic additive. 相似文献
38.
Edyta Wernio Anna Kosowska Agnieszka Kuchta Agnieszka wikliska Kornelia Saaga-Zaleska Maciej Jankowski Przemysaw Kosowski Piotr Winiewski Jolanta Wierzba Sylwia Magorzewicz 《Nutrients》2022,14(12)
Introduction: The risk of obesity in children with Down syndrome is high. Undoubtedly, proper nutrition plays an important role in the prevention of excess body weight and is associated with a reduction of metabolic complications. The aim of the study was to assess the problem of disturbances in the nutritional status and eating habits of children with DS. Methods: A total of 39 patients were included in the study. The nutritional status was assessed by anthropometric tests and Dual X-ray Absorptiometry. Eating habits were assessed using the Child Eating Behavior Questionnaire and the Food Frequency Questionnaire. Blood samples were taken to determine the oxidative stress and lipid parameters. Results: Obesity was recognized in 15% of subjects and 23% were overweight. Children that were overweight were characterized by higher levels of triglycerides, atherogenic index of plasma, and apoA2 and apoE levels. Fat mass, fat mass/height2 index, and visceral fat mass correlated with thiobarbituric acid reactive substances and advanced oxidative protein product level. The analysis of the Child Eating Behavior Questionnaire showed that children struggling with being overweight were more interested in food compared to those with normal body weight. A positive correlation was identified between waist circumference and food interest categories. Insufficient consumption of dairy products, vegetables, whole grain products, as well as fruits, seeds, nuts, and fatty fish was noted. Patients were less likely to consume products that are a good source of mono- and polyunsaturated fatty acids. Conclusions: In children with Down syndrome and obesity, disturbances in lipid and oxidative stress parameters are observed. Abnormal eating habits in all children with Down syndrome regardless of their nutritional status were noted. Proper nutritional education, nutritional control, and management of metabolic problems are essential in this group of patients. 相似文献
39.
Bartomiej Jagodziski Piotr Rytlewski Krzysztof Moraczewski Andrzej Trafarski Tomasz Karasiewicz 《Materials》2022,15(15)
The article presents research on the potential use of organometallic compounds with the addition of antimony (III) oxide Sb2O3 as a coating additive that will make coatings susceptible to electroless metallization after prior surface irradiation with 193 nm wavelength laser radiation and a different number of laser pulses. The surface modification and activation effects were assessed by optical-imagining as well as by scanning electron microscopy (SEM) with energy dispersive analysis (EDX). It was found that the presence of Sb2O3 in the coating made it possible to reduce the content of the copper complex, causing an intensive surface ablation, resulting in the formation of a conical structure with a higher content of metallic copper nuclei. 相似文献
40.
Modelling of the Flow in the Process of Washing Out Automotive Catalyst Carriers with the PbLi Alloy
Mariola Saternus Agnieszka Fornalczyk Wadysaw Gsior Adam Dbski Sylwia Terlicka Sawomir Golak Piotr Ciepliski 《Materials》2022,15(9)
The process of platinum recovery from used car catalysts is highly desirable for both economic and environmental reasons. From the many available methods of processing used car catalysts, the article conducted both numerical and experimental studies using a device based on the collector metal method with lead as a modified medium through a magnetohydrodynamic pump for washing platinum from the channels of the ceramic catalyst carrier. It was assumed that lead alloys with the addition of lithium increase the extraction of platinum from thin catalytic layers and accelerate the platinum dissolution reaction in the Pb-Li alloy, which is the result of a greater affinity of lithium for platinum compared to lead. This assumption was verified by numerical simulations as well as laboratory tests. Tests were carried out for the secondary supply voltage range between 40 and 60 V and the catalyst flushing time between 240 and 480 s. Graphical results of the research were discussed. 相似文献