全文获取类型
收费全文 | 1173758篇 |
免费 | 77188篇 |
国内免费 | 1397篇 |
专业分类
耳鼻咽喉 | 16668篇 |
儿科学 | 38205篇 |
妇产科学 | 30986篇 |
基础医学 | 168239篇 |
口腔科学 | 33176篇 |
临床医学 | 102735篇 |
内科学 | 220968篇 |
皮肤病学 | 27451篇 |
神经病学 | 91912篇 |
特种医学 | 47318篇 |
外国民族医学 | 201篇 |
外科学 | 178321篇 |
综合类 | 22109篇 |
一般理论 | 299篇 |
预防医学 | 79902篇 |
眼科学 | 26732篇 |
药学 | 93288篇 |
7篇 | |
中国医学 | 2840篇 |
肿瘤学 | 70986篇 |
出版年
2019年 | 8709篇 |
2018年 | 13476篇 |
2017年 | 10835篇 |
2016年 | 12516篇 |
2015年 | 13332篇 |
2014年 | 17672篇 |
2013年 | 26559篇 |
2012年 | 36215篇 |
2011年 | 38747篇 |
2010年 | 22519篇 |
2009年 | 20127篇 |
2008年 | 36478篇 |
2007年 | 38934篇 |
2006年 | 39250篇 |
2005年 | 37530篇 |
2004年 | 35818篇 |
2003年 | 34652篇 |
2002年 | 33528篇 |
2001年 | 63485篇 |
2000年 | 65863篇 |
1999年 | 53296篇 |
1998年 | 12894篇 |
1997年 | 11255篇 |
1996年 | 11040篇 |
1995年 | 10864篇 |
1994年 | 9869篇 |
1993年 | 9369篇 |
1992年 | 38287篇 |
1991年 | 36709篇 |
1990年 | 36163篇 |
1989年 | 34722篇 |
1988年 | 31224篇 |
1987年 | 30404篇 |
1986年 | 28534篇 |
1985年 | 26953篇 |
1984年 | 19681篇 |
1983年 | 16515篇 |
1982年 | 9258篇 |
1979年 | 17361篇 |
1978年 | 11716篇 |
1977年 | 10538篇 |
1976年 | 9103篇 |
1975年 | 10338篇 |
1974年 | 11901篇 |
1973年 | 11486篇 |
1972年 | 10923篇 |
1971年 | 10270篇 |
1970年 | 9436篇 |
1969年 | 9088篇 |
1968年 | 8082篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
Kari Hemminki Kristina Sundquist Jan Sundquist Asta Försti Vaclav Liska Akseli Hemminki Xinjun Li 《International journal of cancer. Journal international du cancer》2023,152(6):1107-1114
Many environmental risk factors for hepatobiliary cancers are known but whether they are associated with specific cancer types is unclear. We present here a novel approach of assessing standardized incidence ratios (SIRs) of previously diagnosed comorbidities for hepatocellular carcinoma (HCC), gallbladder cancer (GBC), cholangiocarcinoma (CCA) and ampullary cancer. The 13 comorbidities included alcohol and nonalcohol related liver disease, chronic obstructive pulmonary disease, gallstone disease, viral and other kinds of hepatitis, infection of bile ducts, hepatic and other autoimmune diseases, obesity and diabetes. Patients were identified from the Swedish Inpatient Register from 1987 to 2018, and their cancers were followed from 1997 onwards. SIRs for HCC were 80 to 100 in men and women diagnosed with hepatitis C virus and they were also >10 in patients diagnosed with hepatitis B virus, other kind of hepatitis, hepatic autoimmune disease and nonalcohol related liver disease. Many of these risks, as well as alcohol related liver disease, were either specific to HCC or were shared with intrahepatic CCA. For GBC, CCA and ampullary cancer infection of bile ducts was the main risk factor. Gallstone disease, nonhepatic autoimmune diseases and diabetes were associated with all hepatobiliary cancers. The limitations of the study include inability to cover some rare risk factors and limited follow-up time. Many of the considered comorbidities are characterized by chronic inflammation and/or overt immune disturbance in autoimmune diseases. The results suggest that local chronic inflammation and a related immune disturbance is the carcinogenic trigger for all these cancers. 相似文献
2.
3.
Jayaraman Chandrasekaran Embry Kyle R. Mummidisetty Chaithanya K. Moon Yaejin Giffhorn Matt Prokup Sara Lim Bokman Lee Jusuk Lee Younbaek Lee Minhyung Jayaraman Arun 《Journal of neuroengineering and rehabilitation》2022,19(1):1-13
Numerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. Sixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. Statistical analysis used a linear mixed model to evaluate the effects on the center of pressure and the center of mass. The canes significantly reduced the variability of the center of pressure and the center of mass to the same level as when standing on the ground. Increasing the exerted force beyond the preferred level yielded no further benefits, although in the preferred force condition, participants exploited the altered mechanics by resting their arms on the canes. The tripod configuration allowed for larger variability of the center of pressure in the task-irrelevant anterior–posterior dimension. High forces had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. Given this static instability, these results show that using canes can provide not only mechanical benefits but also challenges. From a control perspective, effort can be reduced by resting the arms on the canes and by channeling noise in the task-irrelevant dimensions. However, larger forces exerted onto the canes can also have destabilizing effects and the instability of the canes needs to be counteracted, possibly by arm and shoulder stiffness. Insights into the variety of mechanical effects is important for the design of canes and the instructions of how to use them. 相似文献
4.
Thomas Behrens Calvin Ge Roel Vermeulen Benjamin Kendzia Ann Olsson Joachim Schüz Hans Kromhout Beate Pesch Susan Peters Lützen Portengen Per Gustavsson Dario Mirabelli Pascal Guénel Danièle Luce Dario Consonni Neil E. Caporaso Maria Teresa Landi John K. Field Stefan Karrasch Heinz-Erich Wichmann Jack Siemiatycki Marie-Elise Parent Lorenzo Richiardi Lorenzo Simonato Karl-Heinz Jöckel Wolfgang Ahrens Hermann Pohlabeln Guillermo Fernández-Tardón David Zaridze John R. McLaughlin Paul A. Demers Beata Świątkowska Jolanta Lissowska Tamás Pándics Eleonora Fabianova Dana Mates Vladimir Bencko Lenka Foretova Vladimír Janout Paolo Boffetta Bas Bueno-de-Mesquita Francesco Forastiere Kurt Straif Thomas Brüning 《International journal of cancer. Journal international du cancer》2023,152(4):645-660
There is limited evidence regarding the exposure-effect relationship between lung-cancer risk and hexavalent chromium (Cr(VI)) or nickel. We estimated lung-cancer risks in relation to quantitative indices of occupational exposure to Cr(VI) and nickel and their interaction with smoking habits. We pooled 14 case-control studies from Europe and Canada, including 16 901 lung-cancer cases and 20 965 control subjects. A measurement-based job-exposure-matrix estimated job-year-region specific exposure levels to Cr(VI) and nickel, which were linked to the subjects' occupational histories. Odds ratios (OR) and associated 95% confidence intervals (CI) were calculated by unconditional logistic regression, adjusting for study, age group, smoking habits and exposure to other occupational lung carcinogens. Due to their high correlation, we refrained from mutually adjusting for Cr(VI) and nickel independently. In men, ORs for the highest quartile of cumulative exposure to CR(VI) were 1.32 (95% CI 1.19-1.47) and 1.29 (95% CI 1.15-1.45) in relation to nickel. Analogous results among women were: 1.04 (95% CI 0.48-2.24) and 1.29 (95% CI 0.60-2.86), respectively. In men, excess lung-cancer risks due to occupational Cr(VI) and nickel exposure were also observed in each stratum of never, former and current smokers. Joint effects of Cr(VI) and nickel with smoking were in general greater than additive, but not different from multiplicative. In summary, relatively low cumulative levels of occupational exposure to Cr(VI) and nickel were associated with increased ORs for lung cancer, particularly in men. However, we cannot rule out a combined classical measurement and Berkson-type of error structure, which may cause differential bias of risk estimates. 相似文献
5.
Kawakatsu Sonoko Zhu Rui Zhang Wenhui Tang Meina T. Lu Tong Quartino Angelica L. Kågedal Matts 《Journal of pharmacokinetics and pharmacodynamics》2022,49(2):179-190
Journal of Pharmacokinetics and Pharmacodynamics - Clinical trials in patients with ulcerative colitis (UC) face the challenge of high and variable placebo response rates. The Mayo Clinical Score... 相似文献
6.
7.
Die Anaesthesiologie - Die COVID-19-Pandemie hat die medizinische Lehre weltweit verändert. Seit dem Sommersemester 2020 stehen digitale Lehrformate im Fokus, deren Einsatz zuvor in... 相似文献
8.
Eskelinen Tommi Veitonmäki Thea Kotsar Andres Tammela Teuvo L. J. Pöyhönen Antti Murtola Teemu J. 《Cancer causes & control : CCC》2022,33(2):313-320
Cancer Causes & Control - We explored renal cell cancer (RCC) survival among users of antihypertensive medication as hypertension is proposed to be a risk factor for RCC and ACE-inhibitors and... 相似文献
9.
Amutha M. Sankaranarayanan K. Anisha V. 《Proceedings of the National Academy of Sciences, India. Section B.》2022,92(4):897-905
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Adoption of intercropping offers an opportunity to get additional income and to protect the crops from insect... 相似文献
10.
Straub Anton Vollmer Andreas Lâm Thiên-Trí Brands Roman C. Stapf Maximilian Scherf-Clavel Oliver Bittrich Max Fuchs Andreas Kübler Alexander C. Hartmann Stefan 《Clinical oral investigations》2022,26(12):7033-7044
Clinical Oral Investigations - Mechanisms of wound healing are often impaired in patients with osteonecrosis of the jaw (ONJ). According to the guidelines for the treatment of this disease, early... 相似文献