首页 | 本学科首页   官方微博 | 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   9944篇
  免费   381篇
  国内免费   36篇
耳鼻咽喉   82篇
儿科学   204篇
妇产科学   159篇
基础医学   1638篇
口腔科学   189篇
临床医学   872篇
内科学   1929篇
皮肤病学   206篇
神经病学   1153篇
特种医学   468篇
外科学   1622篇
综合类   43篇
一般理论   2篇
预防医学   327篇
眼科学   189篇
药学   647篇
中国医学   20篇
肿瘤学   611篇
  2023年   66篇
  2022年   86篇
  2021年   187篇
  2020年   122篇
  2019年   158篇
  2018年   165篇
  2017年   155篇
  2016年   192篇
  2015年   238篇
  2014年   298篇
  2013年   392篇
  2012年   588篇
  2011年   619篇
  2010年   368篇
  2009年   361篇
  2008年   554篇
  2007年   601篇
  2006年   547篇
  2005年   567篇
  2004年   521篇
  2003年   492篇
  2002年   488篇
  2001年   107篇
  2000年   80篇
  1999年   79篇
  1998年   108篇
  1997年   76篇
  1996年   69篇
  1995年   70篇
  1994年   70篇
  1993年   57篇
  1992年   54篇
  1991年   39篇
  1990年   30篇
  1989年   41篇
  1988年   31篇
  1985年   33篇
  1983年   38篇
  1974年   31篇
  1935年   29篇
  1933年   55篇
  1932年   80篇
  1931年   42篇
  1930年   35篇
  1929年   30篇
  1928年   47篇
  1927年   48篇
  1926年   29篇
  1924年   39篇
  1922年   30篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Subtle subjective visual dysfunctions (VisDys) are reported by about 50% of patients with schizophrenia and are suggested to predict psychosis states. Deeper insight into VisDys, particularly in early psychosis states, could foster the understanding of basic disease mechanisms mediating susceptibility to psychosis, and thereby inform preventive interventions. We systematically investigated the relationship between VisDys and core clinical measures across three early phase psychiatric conditions. Second, we used a novel multivariate pattern analysis approach to predict VisDys by resting-state functional connectivity within relevant brain systems. VisDys assessed with the Schizophrenia Proneness Instrument (SPI-A), clinical measures, and resting-state fMRI data were examined in recent-onset psychosis (ROP, n = 147), clinical high-risk states of psychosis (CHR, n = 143), recent-onset depression (ROD, n = 151), and healthy controls (HC, n = 280). Our multivariate pattern analysis approach used pairwise functional connectivity within occipital (ON) and frontoparietal (FPN) networks implicated in visual information processing to predict VisDys. VisDys were reported more often in ROP (50.34%), and CHR (55.94%) than in ROD (16.56%), and HC (4.28%). Higher severity of VisDys was associated with less functional remission in both CHR and ROP, and, in CHR specifically, lower quality of life (Qol), higher depressiveness, and more severe impairment of visuospatial constructability. ON functional connectivity predicted presence of VisDys in ROP (balanced accuracy 60.17%, p = 0.0001) and CHR (67.38%, p = 0.029), while in the combined ROP + CHR sample VisDys were predicted by FPN (61.11%, p = 0.006). These large-sample study findings suggest that VisDys are clinically highly relevant not only in ROP but especially in CHR, being closely related to aspects of functional outcome, depressiveness, and Qol. Findings from multivariate pattern analysis support a model of functional integrity within ON and FPN driving the VisDys phenomenon and being implicated in core disease mechanisms of early psychosis states.Subject terms: Predictive markers, Psychosis  相似文献   
52.
Costello syndrome (CS) is caused by heterozygous HRAS germline mutations. Most patients share the HRAS variant p.Gly12Ser that is associated with a typical, homogeneous phenotype. Rarer pathogenic HRAS variants (e.g., p.Thr56Ile) were identified in individuals with attenuated CS phenotypes. The obvious phenotypical variability reflects different dysfunctional consequences of distinct HRAS variants. We report on two boys with the novel de novo HRAS variant c.466 C > T p.(Phe156Leu). Both had severe feeding difficulties, airway obstruction and developmental delay, which are typical findings in CS. They showed subtle facial and dermatologic features consistent with attenuated CS. They significantly differed in their musculoskeletal, cardiovascular and endocrinologic manifestations underscoring the clinical variability of individuals with identical, in particular rarer pathogenic HRAS variants. Functional studies revealed enhanced effector-binding, increased downstream signaling activation and impaired growth factor-induced signaling dynamics in cells expressing HRASPhe156Leu. Our data further illustrate the molecular and phenotypic variability of CS.Subject terms: Genetics research, Disease genetics  相似文献   
53.
Polymeric thin films offer a wide range of exciting properties and applications, with several advantages compared to inorganic counterparts. The thermal conductivity of such thin films ranges typically between 0.1–1 W m1 K1. This low thermal conductivity can cause problems with heat dissipation in various applications. Detailed knowledge about thermal transport in polymeric thin films is desired to overcome these shortcomings, especially in light of the multitude of possible microstructures for semi-crystalline thin films. Therefore, poly(3-hexylthiophene-2,5-diyl) (P3HT) is chosen as a model system to analyze the microstructure and optoelectronic properties using X-ray scattering and absorption spectra along with the thermal transport properties using the photoacoustic technique. This combination of analysis methods allows for determining the optoelectronic and thermal transport properties on the same specimen, supplemented by structural information. The effect of different molecular weights and solvents during film preparation is systematically examined. A variation of the optoelectronic properties, mainly regarding molecular weight, is apparent, while no direct influence of the solvent during preparation is discernible. In contrast, the thermal conductivities of all films examined fall within a similar range. Therefore, the microstructural properties in the ordered regions do not significantly affect the resulting thermal properties in the sample space investigated in this work. We conclude that it is mainly the amorphous regions that determine the thermal transport properties, as these represent a bottleneck for thermal transport.  相似文献   
54.
The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) facilitates viral entry into host cells and is the key target for neutralizing antibodies. The SARS-CoV-2 lineage B.1.620 carries fifteen mutations in the S protein and is spread in Africa, the US and Europe, while lineage R.1 harbors four mutations in S and infections were observed in several countries, particularly Japan and the US. However, the impact of the mutations in B.1.620 and R.1 S proteins on antibody-mediated neutralization and host cell entry are largely unknown. Here, we report that these mutations are compatible with robust ACE2 binding and entry into cell lines, and they markedly reduce neutralization by vaccine-induced antibodies. Our results reveal evasion of neutralizing antibodies by B.1.620 and R.1, which might have contributed to the spread of these lineages.  相似文献   
55.
56.
57.
58.
    
Zusammenfassung Durch Zeitstudien und Messung der Leistungsf?higkeit wurde an 36 Frauen in einer 9w?chentlichen Versuchsreihe der Einflu? von Tee bzw. einer w?hrend der Nachtarbeit genommenen warmen Mahlzeit untersucht. Die Messung der Leistungsf?higkeit am Ende der Nachtschicht ergab in der Periode des Teegenusses eine Senkung um 16%, unter dem Einflu? der warmen Mahlzeit eine Steigerung um durchschnittlich 10%. Auf den zeitlichen Ablauf der Arbeit übten weder der Tee noch die warme Mahlzeit einen Einflu? aus. Mit 3 Textabbildungen.  相似文献   
59.
Ohne ZusammenfassungNach einem am 8. und 15. Novbr. 1871 unter Demonstration der Originalpräparate in der Berliner med. Gesellschaft gehaltenen Vortrage. Hierzu Taf. I–III.  相似文献   
60.
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