全文获取类型
收费全文 | 5844篇 |
免费 | 375篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 181篇 |
妇产科学 | 64篇 |
基础医学 | 938篇 |
口腔科学 | 149篇 |
临床医学 | 471篇 |
内科学 | 1095篇 |
皮肤病学 | 253篇 |
神经病学 | 824篇 |
特种医学 | 298篇 |
外科学 | 407篇 |
综合类 | 29篇 |
一般理论 | 1篇 |
预防医学 | 430篇 |
眼科学 | 130篇 |
药学 | 427篇 |
中国医学 | 13篇 |
肿瘤学 | 491篇 |
出版年
2024年 | 4篇 |
2023年 | 49篇 |
2022年 | 69篇 |
2021年 | 129篇 |
2020年 | 110篇 |
2019年 | 132篇 |
2018年 | 147篇 |
2017年 | 120篇 |
2016年 | 142篇 |
2015年 | 199篇 |
2014年 | 222篇 |
2013年 | 285篇 |
2012年 | 483篇 |
2011年 | 465篇 |
2010年 | 283篇 |
2009年 | 274篇 |
2008年 | 415篇 |
2007年 | 385篇 |
2006年 | 378篇 |
2005年 | 389篇 |
2004年 | 330篇 |
2003年 | 323篇 |
2002年 | 319篇 |
2001年 | 48篇 |
2000年 | 41篇 |
1999年 | 69篇 |
1998年 | 85篇 |
1997年 | 64篇 |
1996年 | 51篇 |
1995年 | 42篇 |
1994年 | 30篇 |
1993年 | 36篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 13篇 |
1989年 | 13篇 |
1988年 | 14篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1968年 | 2篇 |
排序方式: 共有6240条查询结果,搜索用时 0 毫秒
11.
12.
Grisk O Lother U Gabriëls G Rettig R 《Pflügers Archiv : European journal of physiology》2005,449(4):364-371
Renal transplantation experiments have shown that the kidney contributes to chronic sympathectomy-induced arterial pressure reduction in spontaneously hypertensive rats (SHR). The underlying mechanisms are currently unclear but may include alterations in the function of small renal arteries. Neonatal SHR were sympathectomized by intraperitoneal guanethidine injections and removal of adrenal medullary tissue. Controls were sham- or hydralazine-treated. At 12 weeks of age, distal interlobar artery segments were investigated using small-vessel wire myography. Vessels from sympathectomized animals showed increased sensitivity to noradrenaline (NE). Vasopressin- and endothelin-1-induced vasoconstriction was similar in all groups (as reflected by the pD2, i.e. –logEC50, where EC50 is the molar concentration of agonist eliciting a half-maximal response). Maximum vasopressin-induced tension was similar in all groups while endothelin-1-induced maximum tension was significantly higher in sympathectomized than in sham-treated SHR. The sensitivity of NE-induced vasoconstriction to extracellular Ca2+ did not differ between groups while sensitivity to L-type Ca2+ channel activation was significantly higher in both sympathectomized and hydralazine-treated animals than in sham-treated animals. Endothelium-dependent and independent vasodilation were similar in all groups. Sequential blockade of NO-synthase and cyclooxygenase had similar effects in all groups. In conclusion, neonatal sympathectomy does not induce any changes in the function of isolated proximal renal resistance arteries from SHR that could explain the blood pressure lowering effect of a kidney graft from sympathectomized SHR. 相似文献
13.
Hüffmeier U Hausser I Reis A Rauch A 《American journal of medical genetics. Part A》2005,135(2):195-199
We present a family of Iraqui origin with three siblings affected by a novel type of progressive hyperpigmentation syndrome. The generalized initially diffuse, later disseminated hyperpigmentation started in early infancy and increased during childhood. It also affected palms and soles, and the face but spared the cheeks. Additional features were dry, itchy and sunlight sensitive skin, dystrophy of toe nails, hair loss, and myopia, but normal sweat glands. Light and electron microscopy showed signs of pigment incontinence and compound melanosomes as well as fibrillar bodies. The occurrence of this entity in affected siblings from a consanguineous mating suggests autosomal recessive inheritance. Extensive review of the literature showed no previous report with this distinct combination of clinical and microscopic findings. 相似文献
14.
15.
Reiners J van Wijk E Märker T Zimmermann U Jürgens K te Brinke H Overlack N Roepman R Knipper M Kremer H Wolfrum U 《Human molecular genetics》2005,14(24):3933-3943
Usher syndrome (USH) is the most frequent cause of combined deaf-blindness in man. USH is clinically and genetically heterogeneous with at least 11 chromosomal loci assigned to the three USH types (USH1A-G, USH2A-C, USH3A). Although the different USH types exhibit almost the same phenotype in human, the identified USH genes encode for proteins which belong to very different protein classes and families. We and others recently reported that the scaffold protein harmonin (USH1C-gene product) integrates all identified USH1 molecules in a USH1-protein network. Here, we investigated the relationship between the USH2 molecules and this USH1-protein network. We show a molecular interaction between the scaffold protein harmonin (USH1C) and the USH2A protein, VLGR1 (USH2C) and the candidate for USH2B, NBC3. We pinpoint these interactions to interactions between the PDZ1 domain of harmonin and the PDZ-binding motifs at the C-termini of the USH2 proteins and NBC3. We demonstrate that USH2A, VLGR1 and NBC3 are co-expressed with the USH1-protein harmonin in the synaptic terminals of both retinal photoreceptors and inner ear hair cells. In hair cells, these USH proteins are also localized in the signal uptaking stereocilia. Our data indicate that the USH2 proteins and NBC3 are further partners in the supramolecular USH-protein network in the retina and inner ear which shed new light on the function of USH2 proteins and the entire USH-protein network. These findings provide first evidence for a molecular linkage between the pathophysiology in USH1 and USH2. The organization of USH molecules in a mutual 'interactome' related to the disease can explain the common phenotype in USH. 相似文献
16.
Morphological detection and quantification of lipoprotein(a) deposition in atheromatous lesions of human aorta and coronary arteries 总被引:8,自引:0,他引:8
Axel Niendorf Matthias Rath Katrin Wolf Susanne Peters Hartmut Arps Ulrike Beisiegel Manfred Dietel 《Virchows Archiv : an international journal of pathology》1990,417(2):105-111
Summary Lipoprotein(a), as an atherogenic particle, represents an independent risk factor for coronary heart disease. In the present
study the morphological distribution of apoprotein (a) and apoprotein B within the arterial wall is described. Apoprotein
B, a constituent of very low-density lipoprotein, low-density lipoprotein and lipoprotein(a) has previously been demonstrated
in atheromatous lesions. Lipoprotein(a) possesses an additional protein, designated apoprotein (a). Autopsy material (n=74) from the left coronary artery and from the thoracic aorta has been examined by means of immunohistochemistry and both
apoprotein (a) and apoprotein B were detected, primarily associated with the extracellular matrix and accumulating in lesions
in the arterial wall. The staining pattern for both antigens was almost always found to be congruent, suggesting that the
detection of (a)-antigen has to be attributed at least in part to the presence of lipoprotein(a). It is concluded that both
low-density lipoprotein and lipoprotein(a) have an important role in the pathogenesis of atherosclerosis. 相似文献
17.
Ulrike Horstmann Bernd Arnold Günter J. Hmmerling 《European journal of immunology》1986,16(7):863-865
We and others have previously reported that homologous exchange of alpha 1 or alpha 2 domains between different alleles led to loss of most determinants recognized by cytotoxic T lymphocytes (CTL) raised against the parental H-2 class I antigens. Here we demonstrate that exchange of alpha 1 or alpha 2 domains between the Kk and Kd allele results in the formation of neodeterminants against which allospecific CTL can be generated in responder mice of various related and unrelated H-2 haplotypes. In fact, only CTL against the neodeterminants on the hybrid molecules were found and none against the parental Kk and Kd determinants. In addition our data show that recognition of the neodeterminants is H-2 unrestricted. These findings suggest that in the hybrid molecules the basic structure of a major histocompatibility complex molecule has been preserved although most parental allodeterminants on the alpha 1 and alpha 2 domains have been modified. 相似文献
18.
Ulrike Fuhrmann Karsten Parczyk Michael Klotzbücher Helmut Klocker A. C. B. Cato 《Journal of molecular medicine (Berlin, Germany)》1998,76(7):512-524
Antihormones are by definition antagonists of steroid hormone action. They interact with the ligand binding domains of steroid
hormone receptors and competitively inhibit the action of the receptors by mechanisms that are not quite understood. In certain
cases antihormones also exhibit agonistic activity especially in connection with certain naturally occurring receptor mutants.
These observations together with findings of indiscriminate interaction of antihormones with several classes of steroid receptors
have necessitated a search of more effective and reliable antihormones. Recent advances in the resolution of the crystal structure
of the ligand binding domains of certain members of the steroid receptor family and identification of non-liganded activation
of steroid receptors have produced considerable information that can be harnessed into a fruitful search for a new generation
of antihormones.
Received: 19 June 1997 / Accepted: 10 October 1997 相似文献
19.
20.
The Topography of Non-Linear Cortical Dynamics at Rest, in Mental Calculation and Moving Shape Perception 总被引:3,自引:0,他引:3
Andreas Meyer-Lindenberg Ulrike Bauer Stefan Krieger Stefanie Lis Kinga Vehmeyer Georg Schüler Bernd Gallhofer 《Brain topography》1998,10(4):291-299
Differential cortical activation by cognitive processing was studied using dimensional complexity, a measure derived from nonlinear dynamics that indicates the degrees of freedom (complexity) of a dynamic system. We examined the EEG of 32 healthy subjects at rest, during a visually presented calculation task, and during a moving shape perception task. As a nonlinear measure of connectivity, the mutual dimension of selected electrode pairs was used. The first Lyapunov coefficient was also calculated. Data were tested for non-linearity using a surrogate data method and compared to spectral EEG measures (power, coherence). Surrogate data testing confirmed the presence of nonlinear structure in the data. Cognitive activation led to a highly significant rise in dimensional complexity. While both tasks activated central, parietal and temporal areas, mental arithmetic showed frontal activation and an activity maximum at T3, while the moving shape task led to occipital activation and a right parietal activity maximum. Analysis of mutual dimension showed activation of a bilateral temporal-right frontal network in calculation. The Lyapunov coefficent showed clear topographic variation, but was not significantly changed by mental tasks (p<.09). While dimensional complexity was almost unrelated to power values, nonlinear (mutual dimension) and linear (coherence) measures of connectivity shared up to 37% of variance. Data are interpreted in terms of increased cortical complexity as a result of recruitment of asynchronously active, distributed neuronal assemblies in cognition. The topography of nonlinear dynamics are related to neuropsychological and neuroimaging findings on mental calculation and moving shape perception. 相似文献