全文获取类型
收费全文 | 1317698篇 |
免费 | 83401篇 |
国内免费 | 2016篇 |
专业分类
耳鼻咽喉 | 16414篇 |
儿科学 | 36272篇 |
妇产科学 | 30676篇 |
基础医学 | 178842篇 |
口腔科学 | 34166篇 |
临床医学 | 112619篇 |
内科学 | 258434篇 |
皮肤病学 | 22584篇 |
神经病学 | 108665篇 |
特种医学 | 52718篇 |
外国民族医学 | 92篇 |
外科学 | 214619篇 |
综合类 | 24050篇 |
现状与发展 | 3篇 |
一般理论 | 516篇 |
预防医学 | 98596篇 |
眼科学 | 28313篇 |
药学 | 96367篇 |
4篇 | |
中国医学 | 3124篇 |
肿瘤学 | 86041篇 |
出版年
2021年 | 8758篇 |
2019年 | 9111篇 |
2018年 | 35126篇 |
2017年 | 27948篇 |
2016年 | 31997篇 |
2015年 | 13599篇 |
2014年 | 18447篇 |
2013年 | 26507篇 |
2012年 | 43131篇 |
2011年 | 59688篇 |
2010年 | 41086篇 |
2009年 | 33089篇 |
2008年 | 58013篇 |
2007年 | 63216篇 |
2006年 | 39941篇 |
2005年 | 41575篇 |
2004年 | 41717篇 |
2003年 | 41569篇 |
2002年 | 38538篇 |
2001年 | 57074篇 |
2000年 | 58742篇 |
1999年 | 49231篇 |
1998年 | 13677篇 |
1997年 | 12110篇 |
1996年 | 11896篇 |
1995年 | 10984篇 |
1994年 | 10159篇 |
1993年 | 9326篇 |
1992年 | 36925篇 |
1991年 | 35277篇 |
1990年 | 34007篇 |
1989年 | 33020篇 |
1988年 | 30178篇 |
1987年 | 29440篇 |
1986年 | 27427篇 |
1985年 | 26355篇 |
1984年 | 19374篇 |
1983年 | 16660篇 |
1982年 | 9635篇 |
1981年 | 8350篇 |
1979年 | 16718篇 |
1978年 | 11627篇 |
1977年 | 10005篇 |
1976年 | 8788篇 |
1975年 | 9323篇 |
1974年 | 11208篇 |
1973年 | 10485篇 |
1972年 | 9821篇 |
1971年 | 9216篇 |
1970年 | 8809篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Autoimmune comorbid diseases associated with lichen planus: a nationwide case–control study 下载免费PDF全文
22.
M.T. Leccia N. Auffret F. Poli J.‐P. Claudel S. Corvec B. Dreno 《Journal of the European Academy of Dermatology and Venereology》2015,29(8):1485-1492
Acne vulgaris (acne) is a chronic inflammatory disease of the sebaceous gland, characterized by follicular hyperkeratinization, excessive colonization by Propionibacterium acnes (P. acnes) as well as immune reactions and inflammation. Despite an armamentarium of topical treatments available including benzoyl peroxide, retinoids and azelaic acid, topical antibiotics in monotherapies, especially erythromycin and clindamycin, are still used in Europe to treat acne. This intensive use led to antimicrobial‐resistant P. acnes and staphylococci strains becoming one of the main health issues worldwide. This is an update on the current topical acne treatments available in Europe, their mechanism of action, their potential to induce antimicrobial resistance and their clinical efficacy and safety. 相似文献
23.
Loss‐of‐function mutations in the gene encoding filaggrin underlie a Japanese family with food‐dependent exercise‐induced anaphylaxis 下载免费PDF全文
24.
Seyed Mehdi BagheriMofidi Majid Pouladian Seyed Behnamedin Jameie Ali Abbaspour Tehrani-Fard 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2016,39(3):717-726
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. 相似文献
25.
26.
Y.R. Song B. Wu Y.T. Yang J. Chen L.J. Zhang Z.W. Zhang H.Y. Shi C.L. Huang J.X. Pan P. Xie 《Brazilian journal of medical and biological research》2015,48(11):973-982
Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2%
of the general population of different European countries. Unfortunately, there is no
objective laboratory-based test to aid BD diagnosis or monitor its progression, and
little is known about the molecular basis of BD. Here, we performed a comparative
proteomic study to identify differentially expressed plasma proteins in various BD
mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A
total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched
healthy control subjects were recruited. Seven high-abundance proteins were
immunodepleted in plasma samples from the 4 experimental groups, which were then
subjected to proteome-wide expression profiling by two-dimensional electrophoresis
and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem
mass spectrometry. Proteomic results were validated by immunoblotting and
bioinformatically analyzed using MetaCore. From a total of 32 proteins identified
with 1.5-fold changes in expression compared with healthy controls, 16 proteins were
perturbed in BD independent of mood state, while 16 proteins were specifically
associated with particular BD mood states. Two mood-independent differential
proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be
associated with early perturbations in lipid metabolism. Moreover, down-regulation of
one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved
in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be
associated with early perturbations in lipid metabolism that are independent of mood
state, while CA-1 may be involved in the pathophysiology of depressive episodes. 相似文献
27.
John Bickle 《Topics in Cognitive Science》2015,7(2):299-311
David Marr's three-level method for completely understanding a cognitive system and the importance he attaches to the computational level are so familiar as to scarcely need repeating. Fewer seem to recognize that Marr defends his famous method by criticizing the “reductionistic approach.” This sets up a more interesting relationship between Marr and reductionism than is usually acknowledged. I argue that Marr was correct in his criticism of the reductionists of his time—they were only describing (cellular activity), not explaining (cognitive functions). But a careful metascientific account of reductionistic neuroscience over the past two decades reveals that Marr's criticisms no longer have force. Contemporary neuroscience now explains cognition directly, although in a fashion—causal-mechanistically—quite different than Marr recommended. So while Marr was correct to reject the reductionism of his day and offer an alternative method for genuinely explaining cognition, contemporary cognitive scientists now owe us a new defense of Marr's famous method and the advantages of its explanations over the type now pursued successfully in current reductionist neuroscience. There are familiar reasons for thinking that this debt will not be paid easily. 相似文献
28.
29.
30.
O. Ieromina C. J. M. Musters P. M. Bodegom W. J. G. M. Peijnenburg M. G. Vijver 《Ecotoxicology (London, England)》2016,25(6):1170-1180
Analyzing functional species’ characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2–4 % to pesticides, and for 3–11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches. 相似文献