全文获取类型
收费全文 | 2897篇 |
免费 | 208篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 59篇 |
妇产科学 | 68篇 |
基础医学 | 460篇 |
口腔科学 | 65篇 |
临床医学 | 289篇 |
内科学 | 583篇 |
皮肤病学 | 34篇 |
神经病学 | 172篇 |
特种医学 | 166篇 |
外国民族医学 | 2篇 |
外科学 | 379篇 |
综合类 | 41篇 |
一般理论 | 1篇 |
预防医学 | 224篇 |
眼科学 | 45篇 |
药学 | 290篇 |
中国医学 | 2篇 |
肿瘤学 | 202篇 |
出版年
2021年 | 27篇 |
2020年 | 22篇 |
2019年 | 25篇 |
2018年 | 50篇 |
2017年 | 36篇 |
2016年 | 41篇 |
2015年 | 44篇 |
2014年 | 53篇 |
2013年 | 88篇 |
2012年 | 109篇 |
2011年 | 118篇 |
2010年 | 76篇 |
2009年 | 60篇 |
2008年 | 104篇 |
2007年 | 113篇 |
2006年 | 114篇 |
2005年 | 109篇 |
2004年 | 118篇 |
2003年 | 106篇 |
2002年 | 108篇 |
2001年 | 91篇 |
2000年 | 96篇 |
1999年 | 99篇 |
1998年 | 49篇 |
1997年 | 44篇 |
1996年 | 23篇 |
1995年 | 24篇 |
1992年 | 67篇 |
1991年 | 80篇 |
1990年 | 81篇 |
1989年 | 67篇 |
1988年 | 62篇 |
1987年 | 62篇 |
1986年 | 46篇 |
1985年 | 53篇 |
1984年 | 39篇 |
1983年 | 43篇 |
1982年 | 24篇 |
1981年 | 36篇 |
1979年 | 44篇 |
1978年 | 42篇 |
1977年 | 33篇 |
1976年 | 20篇 |
1975年 | 29篇 |
1974年 | 47篇 |
1973年 | 27篇 |
1972年 | 21篇 |
1971年 | 20篇 |
1970年 | 21篇 |
1969年 | 21篇 |
排序方式: 共有3112条查询结果,搜索用时 15 毫秒
81.
Martin Steinau Mona Saraiya Marc T. Goodman Edward S. Peters Meg Watson Jennifer L. Cleveland Charles F. Lynch Edward J. Wilkinson Brenda Y. Hernandez Glen Copeland Maria S. Saber Claudia Hopenhayn Youjie Huang Wendy Cozen Christopher Lyu Elizabeth R. Unger the HPV Typing of Cancers Workgroup 《Emerging infectious diseases》2014,20(5):822-828
We conducted a study to determine prevalence of HPV types in oropharyngeal cancers in the United States and establish a prevaccine baseline for monitoring the impact of vaccination. HPV DNA was extracted from tumor tissue samples from patients in whom cancer was diagnosed during 1995–2005. The samples were obtained from cancer registries and Residual Tissue Repository Program sites in the United States. HPV was detected and typed by using PCR reverse line blot assays. Among 557 invasive oropharyngeal squamous cell carcinomas, 72% were positive for HPV and 62% for vaccine types HPV16 or 18. Prevalence of HPV-16/18 was lower in women (53%) than in men (66%), and lower in non-Hispanic Black patients (31%) than in other racial/ethnic groups (68%–80%). Results indicate that vaccines could prevent most oropharyngeal cancers in the United States, but their effect may vary by demographic variables. 相似文献
82.
Nathaniel R. Riggs Hee-Sung Shin Jennifer B. Unger Donna Spruijt-Metz Mary Ann Pentz 《Journal of immigrant and minority health / Center for Minority Public Health》2014,16(5):914-921
The study purpose was to test 1-year prospective associations between English–Spanish bilingualism and executive function in 5th to 6th grade students while controlling for biculturalism. Participants included 182 US Latino students (50 % female). Self-report surveys assessed biculturalism, bilingualism, and executive function (i.e., working memory, organizational skills, inhibitory control, and emotional control, as well as a summary executive function score). General linear model regressions demonstrated that bilingualism significantly predicted the summary executive function score as well as working memory such that bilingual proficiency was positively related to executive function. Results are the first to demonstrate (a) prospective associations between bilingualism to executive function while controlling for the potential third variable of biculturalism, and (b) a principal role for working memory in this relationship. Since executive function is associated with a host of health outcomes, one implication of study findings is that bilingualism may have an indirect protective influence on youth development. 相似文献
83.
Justin D. Rivard Ashley S. Vergis Bertram J. Unger Krista M. Hardy Chris G. Andrew Lawrence M. Gillman Jason Park 《Surgical endoscopy》2014,28(6):1921-1928
Background
Computer-based surgical simulators capture a multitude of metrics based on different aspects of performance, such as speed, accuracy, and movement efficiency. However, without rigorous assessment, it may be unclear whether all, some, or none of these metrics actually reflect technical skill, which can compromise educational efforts on these simulators. We assessed the construct validity of individual performance metrics on the LapVR simulator (Immersion Medical, San Jose, CA, USA) and used these data to create task-specific summary metrics.Methods
Medical students with no prior laparoscopic experience (novices, N = 12), junior surgical residents with some laparoscopic experience (intermediates, N = 12), and experienced surgeons (experts, N = 11) all completed three repetitions of four LapVR simulator tasks. The tasks included three basic skills (peg transfer, cutting, clipping) and one procedural skill (adhesiolysis).Results
We selected 36 individual metrics on the four tasks that assessed six different aspects of performance, including speed, motion path length, respect for tissue, accuracy, task-specific errors, and successful task completion. Four of seven individual metrics assessed for peg transfer, six of ten metrics for cutting, four of nine metrics for clipping, and three of ten metrics for adhesiolysis discriminated between experience levels. Time and motion path length were significant on all four tasks. We used the validated individual metrics to create summary equations for each task, which successfully distinguished between the different experience levels.Conclusion
Educators should maintain some skepticism when reviewing the plethora of metrics captured by computer-based simulators, as some but not all are valid. We showed the construct validity of a limited number of individual metrics and developed summary metrics for the LapVR. The summary metrics provide a succinct way of assessing skill with a single metric for each task, but require further validation. 相似文献84.
Ronald E. Unger Kirsten Peters Anne Sartoris Christian Freese C. James Kirkpatrick 《Biomaterials》2014
Endotoxin, also known as lipopolysaccharide (LPS) produced by bacteria can be present in any liquid or on any biomaterial even if the material is sterile. Endotoxin in mammals can cause fever, inflammation, cell and tissue damage and irreversible septic shock and death. In the body, endothelial cells making up the blood vasculature and endothelial cells in vitro rapidly react to minute amounts of endotoxin resulting in a rapid induction of the cell adhesion molecule E-selectin. In this study we have used immunofluorescent staining to evaluate the expression of E-selectin on human microvascular endothelial cells from the skin (HDMEC) and human umbilical vein endothelial cells (HUVEC) exposed to various concentrations of LPS. In addition, the sensitivity of detection was compared with the most widely used assay for the presence of endotoxin, the Limulus Amebocyte Lysate assay (LAL). The detection of E-selectin on endothelial cells in the presence of LPS for 4 h was found to be at least as sensitive in detecting the same concentration using the LAL assay. A cell adhesion molecule-enzyme immunosorbent assay was also developed and used to quantify LPS using the endothelial cell model. A comparison of LAL and the immunofluorescent staining method was carried out with solutions, nanoparticles, biomaterial extracts and endothelial cells grown directly on biomaterials. Under all conditions, the endothelial/E-selectin model system was positive for the test samples that were positive by LAL. Thus, we propose the use of this highly sensitive, rapid, reproducible assay for the routine testing of endotoxin in all steps in the manufacturing process of materials destined for use in humans. This can give a rapid feedback and localization of bacterial contamination sources with the LAL being reserved for the testing of the final product. 相似文献
85.
Patrick Unger Sven Klimpel Thomas Lang Harry Wilhelm Palm 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2014,59(3):518-528
Zoographical distribution of metazoan fish parasites in herring, Clupea harengus, from the Baltic Sea was analysed in order to use them as potential biological indicators. A total of 210 herring from six different sampling sites were investigated, harbouring 12 different parasite species [five digeneans (D), one cestode (C), three nematodes (N) and three acanthocephalans (A)]. The distribution of the parasite species differed according to region, with a distinct gradient of decreasing species richness towards the east of the Baltic Sea. The western localities at Kiel Bay, Rügen and Poland had the highest parasite diversity, including the marine parasite species Anisakis simplex (s.s.) (N), Brachyphallus crenatus and Hemiurus luehei (both D). The eastern localities had low parasite species richness, predominated by the freshwater digenean Diplostomum spathaceum. We could identify three different Baltic herring stocks, the spring-spawning herring of the western Baltic reaching from the Kattegat to the German and Polish coast, the stock of the central Baltic proper and the northern stock of C. harengus var. membras of the Gulf of Finland. The limited distribution of the herring parasites within the Baltic Sea enables their use as biological indicators for migration patterns and stock separation. The acanthocephalan Pomphorhynchus laevis that has already been used as an accumulation bioindicator for heavy metals was only recorded for the western herring stocks. However, the presence of mainly generalistic parasites and their uneven distribution patterns make their use as indicators for regional environmental and global change more difficult. 相似文献
86.
87.
Clara Unger Peter Bronsert Kerstin Michalski Anna Bicker Ingolf Juhasz-Bss 《Geburtshilfe und Frauenheilkunde》2022,82(1):50
Background Prostate specific membrane antigen (PSMA) is a promising protein for breast cancer patients. It has not only been detected in prostate cancer but is also expressed by tumor cells and the endothelial cells of tumor vessels in breast cancer patients. PSMA plays a role in tumor progression and tumor angiogenesis. For this reason, a number of diagnostic and therapeutic methods to target PSMA have been developed. Method This paper provides a general structured overview of PSMA and its oncogenic potential, with a special focus on its role in breast cancer. This narrative review is based on a selective literature search carried out in PubMed and the library of Freiburg University Clinical Center. The following key words were used for the search: “PSMA”, “PSMA and breast cancer”, “PSMA PET/CT”, “PSMA tumor progression”. Relevant articles were explicitly read through, processed, and summarized. Conclusion PSMA could be a new diagnostic and therapeutic alternative, particularly for triple-negative breast cancer. It appears to be a potential predictive and prognostic marker. Key words: PSMA, breast cancer, radioligand therapy, immunohistochemistry, PET/CT
Abbreviations
- CT
- computed tomography
- ER
- estrogen receptor
- FOLH1
- folate hydrolase 1
- FDG
- fluorodeoxyglucose
- GCPI
- glutamate carboxypeptidase II
- HR
- hormone receptor
- HUVEC
- human umbilical vein endothelial cell
- n. s.
- not significant
- PET
- positron emission tomography
- PR
- progesterone receptor
- PSMA
- prostate specific membrane antigen
- TNBC
- triple-negative breast cancer
- SUV
- standardized uptake value
- VEGF
- vascular endothelial growth factor
88.
Lahner H. Fendler W. P. Theurer S. Unger N. Herrmann K. Schmid K. W. Führer D. 《Best Practice Onkologie》2020,15(7-8):320-333
best practice onkologie - Neuroendokrine Neoplasien (NEN) des Verdauungstrakts stellen eine heterogene Erkrankung mit variabler klinischer Manifestation dar. Sie machen etwa 1 % aller... 相似文献
89.
Thomas Unger Peter J. Horst Martin Bauer Gudrun Demmert Rainer Rettig Peter Rohmeiss 《Brain research》1989,486(1):33-38
The effects of intracerebroventricular (i.c.v.) injections of angiotensin II (ANG II, 10 pg, 100 pg and 10 ng) on renal sodium excretion were investigated in conscious rats instrumented with a chronic urethral catheter. ANG II increased renal sodium excretion dose-dependently with a threshold i.c.v. dose of 10 pg. Only after the highest dose was a concomitant increase in arterial blood pressure and urinary flow observed. The ANG II-induced natriuresis began within 5 min of the i.c.v. injection and lasted for more than 1 h. The angiotensin receptor antagonist saralasin (1 ng, i.c.v.) largely prevented the natriuretic effect of i.c.v. injected ANG II (100 pg). Our results lend further support to the hypothesis that brain ANG II by its potent natriuretic actions may be instrumental in central osmotic control. 相似文献
90.