全文获取类型
收费全文 | 3477篇 |
免费 | 208篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 39篇 |
妇产科学 | 41篇 |
基础医学 | 653篇 |
口腔科学 | 20篇 |
临床医学 | 261篇 |
内科学 | 854篇 |
皮肤病学 | 83篇 |
神经病学 | 367篇 |
特种医学 | 138篇 |
外科学 | 354篇 |
综合类 | 16篇 |
一般理论 | 1篇 |
预防医学 | 149篇 |
眼科学 | 51篇 |
药学 | 324篇 |
中国医学 | 32篇 |
肿瘤学 | 275篇 |
出版年
2023年 | 26篇 |
2022年 | 67篇 |
2021年 | 188篇 |
2020年 | 71篇 |
2019年 | 93篇 |
2018年 | 114篇 |
2017年 | 84篇 |
2016年 | 93篇 |
2015年 | 94篇 |
2014年 | 123篇 |
2013年 | 190篇 |
2012年 | 283篇 |
2011年 | 249篇 |
2010年 | 139篇 |
2009年 | 139篇 |
2008年 | 229篇 |
2007年 | 213篇 |
2006年 | 213篇 |
2005年 | 201篇 |
2004年 | 197篇 |
2003年 | 144篇 |
2002年 | 163篇 |
2001年 | 23篇 |
2000年 | 20篇 |
1999年 | 18篇 |
1998年 | 20篇 |
1997年 | 13篇 |
1996年 | 22篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 20篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 12篇 |
1973年 | 10篇 |
1972年 | 6篇 |
1969年 | 8篇 |
1968年 | 6篇 |
1966年 | 6篇 |
排序方式: 共有3711条查询结果,搜索用时 37 毫秒
91.
Yann Joly Hilary Burton Bartha Maria Knoppers Ida Ngueng Feze Tom Dent Nora Pashayan Susmita Chowdhury William Foulkes Alison Hall Pavel Hamet Nick Kirwan Angus Macdonald Jacques Simard Ine Van Hoyweghen 《European journal of human genetics : EJHG》2014,22(5):575-579
With the development and increasing accessibility of new genomic tools such as next-generation sequencing, genome-wide association studies, and genomic stratification models, the debate on genetic discrimination in the context of life insurance became even more complex, requiring a review of current practices and the exploration of new scenarios. In this perspective, a multidisciplinary group of international experts representing different interests revisited the genetics and life insurance debate during a 2-day symposium ‘Life insurance: breast cancer research and genetic risk prediction seminar'' held in Quebec City, Canada on 24 and 25 September 2012. Having reviewed the current legal, social, and ethical issues on the use of genomic information in the context of life insurance, the Expert Group identified four main questions: (1) Have recent developments in genomics and related sciences changed the contours of the genetics and life insurance debate? (2) Are genomic results obtained in a research context relevant for life insurance underwriting? (3) Should predictive risk assessment and risk stratification models based on genomic data also be used for life insurance underwriting? (4) What positive actions could stakeholders in the debate take to alleviate concerns over the use of genomic information by life insurance underwriters? This paper presents a summary of the discussions and the specific action items recommended by the Expert Group.Access to genetic information by life insurers has been a topic of discussion for many years.1 The possibility of using genetic data to underwrite an applicant''s insurance policy has given rise to concerns about the emergence of ‘genetic discrimination''. Genetic discrimination in the field of life insurance is not necessarily illegal in that in insurance underwriting questions about health, family history of disease, or genetic information may constitute legal exceptions to antidiscrimination legislation.2, 3 Nevertheless, the expression ‘genetic discrimination'' has acquired public notoriety4 and we will use more neutral language in this paper.Countries including Canada, the United States, Russia, and Japan5 have chosen not to adopt laws specifically prohibiting access to genetic data for underwriting by life insurers.6 In these countries, life insurance underwriters treat genetic data like other types of medical or lifestyle data. However, a growing number of countries such as Belgium, France, and Norway5 have chosen to adopt laws to prevent or limit insurers'' access to genetic data for life insurance underwriting. Other countries including Finland and the United Kingdom have developed voluntary arrangements with the industry (ie moratoria) with similar objectives.7Life insurance is a private contract between the policy-holder and the insurer. Its principal role is to provide financial security to the beneficiaries in the event of the insured''s death.8 Because of this important role, life insurance is often required, or strongly recommended for those seeking loans to acquire primary social goods, like housing or cars.9 In Europe, a consequence of the advent of the welfare state is that private insurance has increasingly played a complementary and supplementary role to social insurance by offering additional security and protection to the population. Thus, in this region, insurance is often considered as a social good that allows individuals to live a comfortable life and as a tool to promote social integration.10 In other regions of the world, this social role of life insurance is also recognized to a lesser extent. Given this social role, equitable access to life insurance is perceived as a sensitive issue and cases of denial looked upon negatively in popular media. Although documented incidents of denial or of increased premiums on the basis of genetic information have remained limited to the context of a few relatively well known, highly penetrant, familial, adult-onset, genetic conditions,11 they have nevertheless generated significant public concern. Fear that insurers will have access to genetic information generated in a clinical or research setting for use in underwriting has been reported by several studies as a reason for non-participation in genetic research or recommended clinical genetic testing.12, 13, 14The clinical utility of genetic testing for monogenic disorders such as Huntington disease, and hereditary forms of cancer are well established.15 However, genomic risk profiles based on the known common susceptibility variants have limited utility in risk prediction at the individual level, although they could be used for risk stratification in prevention programmes in populations.16 Today, a new era of genomic research has made it increasingly affordable to scan the entire genome of an individual. Researchers and physicians can interpret these data together with medical and lifestyle information in the form of sophisticated risk prediction models.17 Moreover, improvement in computing technologies coupled with the Internet make predictive information increasingly available, whether through direct-to-consumer marketing of genetic tests, genetic data sharing online communities, or international research database projects. Given these important technological and scientific changes, and their impact on various stakeholders. The term ‘stakeholders'' is used in this text to refer to the following groups of individuals: actuaries (person who computes insurance risk and premium rates based on statistical data), academic researchers, community representatives, ethics committees, genetic counsellors, genomic researchers, human rights experts, insurers, governmental representatives, non-governmental organisations, patient representatives, physicians, policy makers, popular media, reinsurers (company in charge of calculating the risk and premium amount for insuring a particular customer), research participants, and underwriters (company or person in charge of calculating the risk involved in providing insurance for a particular customer and to decide how much should be paid for the premium). This list is not meant to be exhaustive as relevant new groups may emerge as this topic further develops in the coming years. A multidisciplinary group of international experts representing different interests (hereinafter ‘the Expert Group'') revisited the genetics and life insurance debate. The following text presents a summary of the issues discussed and the ‘Action Items'' agreed upon by the Expert Group at the ‘Life Insurance, Risk Stratification, and Personalized Medicine Symposium''. 相似文献
92.
Tatiana S. Demina Anastasia S. Kuryanova Nadejda A. Aksenova Andrey G. Shubnyy Tatiana N. Popyrina Yaroslav V. Sokovikov Elena V. Istranova Pavel L. Ivanov Peter S. Timashev Tatiana A. Akopova 《RSC advances》2019,9(64):37652
Graft-copolymers based on bioresorbable synthetic (oligo-/polylactide) and natural (chitosan and collagen/gelatin) components were synthesized through solid-state reactive co-extrusion and used for fabrication of fibrous non-woven mats via the electrospinning technique. The effect of the macromolecular features of the initial components on the copolymer characteristics was evaluated using FTIR-spectroscopy, differential scanning calorimetry and elemental analysis. Dynamic light scattering analysis showed that the copolymers have a tendency to form stable ultra-fine dispersions with a mean size of macromolecular aggregates of 150 nm within chlorinated solvents. The copolymer-containing non-woven fibrous mats were fabricated via an electrospinning procedure using chloroform as a solvent. An effect of the copolymer composition on the casting solution''s viscosity, conductivity and surface tension was evaluated. Scanning electron microscopy showed that the obtained mats consist of randomly distributed fibers with a mean size of ∼5 μm and a more complex morphology than mats fabricated from neat polylactide. The proposed mechanochemical approach to obtain hybrid copolymeric compositions differs from typical liquid-phase methods in terms of high efficiency, simplicity and cleanness.Amphiphilic chitosan-g-oligo/polylactide graft-copolymers were synthesized through solid-state reactive co-extrusion and used for fabrication of fibrous non-woven mats via the electrospinning technique using chloroform as a solvent. 相似文献
93.
Rat subthalamic nucleus and zona incerta share extensively overlapped representations of cortical functional territories
下载免费PDF全文
![点击此处可从《The Journal of comparative neurology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The subthalamic nucleus (STN) and the zona incerta (ZI) are two major structures of the subthalamus. The STN has strong connections between the basal ganglia and related nuclei. The ZI has strong connections between brainstem reticular nuclei, sensory nuclei, and nonspecific thalamic nuclei. Both the STN and ZI receive heavy projections from a subgroup of layer V neurons in the cerebral cortex. The major goal of this study was to investigate the following two questions about the cortico‐subthalamic projections using the lentivirus anterograde tracing method in the rat: 1) whether cortical projections to the STN and ZI have independent functional organizations or a global organization encompassing the entire subthalamus as a whole; and 2) how the cortical functional zones are represented in the subthalamus. This study revealed that the subthalamus receives heavy projections from the motor and sensory cortices, that the cortico‐subthalamic projections have a large‐scale functional organization that encompasses both the STN and two subdivisions of the ZI, and that the group of cortical axons that originate from a particular area of the cortex sequentially innervate and form separate terminal fields in the STN and ZI. The terminal zones formed by different cortical functional areas have highly overlapped and fuzzy borders, as do the somatotopic representations of the sensorimotor cortex in the subthalamus. The present study suggests that the layer V neurons in the wide areas of the sensorimotor cortex simultaneously control STN and ZI neurons. Together with other known afferent and efferent connections, possible new functionality of the STN and ZI is discussed. J. Comp. Neurol. 522:4043–4056, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
94.
BackgroundChronic thromboembolic pulmonary hypertension (CTEPH) is a rare, but due to its unfavorable prognosis, feared complication of thromboembolic disease. We assessed the incidence and risk factors for pulmonary hypertension (PH) in a cohort of consecutive patients admitted with pulmonary embolism to the tertiary University Hospital.MethodsIn our cohort of 120 consecutive patients with proved pulmonary embolism (PE) we studied the course of biochemical and echocardiographic parameters with regard to risk factors predicting pulmonary hypertension at the end of hospitalization.ResultsEchocardiographic signs of pulmonary hypertension were present at the time of discharge in more than one half (50.8%) of patients admitted with pulmonary embolism. Predictors of persisting pulmonary hypertension were initial pulmonary hypertension, high initial NT-proBNP levels and age.ConclusionResidual pulmonary hypertension at discharge was present in 50.8% cases, at this time there was a strong relationship between PH and elevated NT-proBNP on admission. The patients will be followed-up and possible development of CTPEH will be evaluated at 6, 12 and 24-month period. 相似文献
95.
Richard Milkovič Peter Telekes Pavel Nedbal Vladimír Hraboš Petra Antonová Rostislav Polášek 《Cor et vasa》2012,54(2):e104-e107
Tumors of the heart are not very common in the population. The clinical symptoms are non-specific and depend on the size and localization of the tumor. Our case report describes a 56 year-old male, who was referred to our facility for selective coronary angiography with a clinical picture of ST segment elevation myocardial infarction. However, the cause of the ECG changes was advanced lung carcinoma growing into the myocardium. 相似文献
96.
Korzhavyi PA Soroka IL Isaev EI Lilja C Johansson B 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(3):686-689
New important applications of copper metal, e.g., in the areas of hydrogen production, fuel cell operation, and spent nuclear fuel disposal, require accurate knowledge of the physical and chemical properties of stable and metastable copper compounds. Among the copper(I) compounds with oxygen and hydrogen, cuprous oxide Cu(2)O is the only one stable and the best studied. Other such compounds are less known (CuH) or totally unknown (CuOH) due to their instability relative to the oxide. Here we combine quantum-mechanical calculations with experimental studies to search for possible compounds of monovalent copper. Cuprous hydride (CuH) and cuprous hydroxide (CuOH) are proved to exist in solid form. We establish the chemical and physical properties of these compounds, thereby filling the existing gaps in our understanding of hydrogen- and oxygen-related phenomena in Cu metal. 相似文献
97.
Control of cell division in Streptococcus pneumoniae by the conserved Ser/Thr protein kinase StkP 总被引:1,自引:0,他引:1
Beilharz K Nováková L Fadda D Branny P Massidda O Veening JW 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(15):E905-E913
How the human pathogen Streptococcus pneumoniae coordinates cell-wall synthesis during growth and division to achieve its characteristic oval shape is poorly understood. The conserved eukaryotic-type Ser/Thr kinase of S. pneumoniae, StkP, previously was reported to phosphorylate the cell-division protein DivIVA. Consistent with a role in cell division, GFP-StkP and its cognate phosphatase, GFP-PhpP, both localize to the division site. StkP localization depends on its penicillin-binding protein and Ser/Thr-associated domains that likely sense uncross-linked peptidoglycan, because StkP and PhpP delocalize in the presence of antibiotics that target the latest stages of cell-wall biosynthesis and in cells that have stopped dividing. Time-lapse microscopy shows that StkP displays an intermediate timing of recruitment to midcell: StkP arrives shortly after FtsA but before DivIVA. Furthermore, StkP remains at midcell longer than FtsA, until division is complete. Cells mutated for stkP are perturbed in cell-wall synthesis and display elongated morphologies with multiple, often unconstricted, FtsA and DivIVA rings. The data show that StkP plays an important role in regulating cell-wall synthesis and controls correct septum progression and closure. Overall, our results indicate that StkP signals information about the cell-wall status to key cell-division proteins and in this way acts as a regulator of cell division. 相似文献
98.
Selfish supernumerary chromosome reveals its origin as a mosaic of host genome and organellar sequences 总被引:1,自引:0,他引:1
MM Martis S Klemme AM Banaei-Moghaddam FR Blattner J Macas T Schmutzer U Scholz H Gundlach T Wicker H Simková P Novák P Neumann M Kubaláková E Bauer G Haseneyer J Fuchs J Dolezel N Stein KF Mayer A Houben 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(33):13343-13346
Supernumerary B chromosomes are optional additions to the basic set of A chromosomes, and occur in all eukaryotic groups. They differ from the basic complement in morphology, pairing behavior, and inheritance and are not required for normal growth and development. The current view is that B chromosomes are parasitic elements comparable to selfish DNA, like transposons. In contrast to transposons, they are autonomously inherited independent of the host genome and have their own mechanisms of mitotic or meiotic drive. Although B chromosomes were first described a century ago, little is known about their origin and molecular makeup. The widely accepted view is that they are derived from fragments of A chromosomes and/or generated in response to interspecific hybridization. Through next-generation sequencing of sorted A and B chromosomes, we show that B chromosomes of rye are rich in gene-derived sequences, allowing us to trace their origin to fragments of A chromosomes, with the largest parts corresponding to rye chromosomes 3R and 7R. Compared with A chromosomes, B chromosomes were also found to accumulate large amounts of specific repeats and insertions of organellar DNA. The origin of rye B chromosomes occurred an estimated ~1.1-1.3 Mya, overlapping in time with the onset of the genus Secale (1.7 Mya). We propose a comprehensive model of B chromosome evolution, including its origin by recombination of several A chromosomes followed by capturing of additional A-derived and organellar sequences and amplification of B-specific repeats. 相似文献
99.
100.
Bruha R Vitek L Marecek Z Pospisilova L Nevsimalova S Martasek P Petrtyl J Urbanek P Jiraskova A Malikova I Haluzik M Ferenci P 《Journal of inherited metabolic disease》2012,35(3):541-548