全文获取类型
收费全文 | 15242篇 |
免费 | 954篇 |
国内免费 | 88篇 |
专业分类
耳鼻咽喉 | 156篇 |
儿科学 | 285篇 |
妇产科学 | 258篇 |
基础医学 | 2048篇 |
口腔科学 | 154篇 |
临床医学 | 1350篇 |
内科学 | 3662篇 |
皮肤病学 | 270篇 |
神经病学 | 1618篇 |
特种医学 | 707篇 |
外科学 | 2671篇 |
综合类 | 32篇 |
一般理论 | 2篇 |
预防医学 | 676篇 |
眼科学 | 138篇 |
药学 | 1021篇 |
中国医学 | 19篇 |
肿瘤学 | 1217篇 |
出版年
2024年 | 12篇 |
2023年 | 108篇 |
2022年 | 172篇 |
2021年 | 471篇 |
2020年 | 224篇 |
2019年 | 455篇 |
2018年 | 538篇 |
2017年 | 357篇 |
2016年 | 361篇 |
2015年 | 444篇 |
2014年 | 691篇 |
2013年 | 802篇 |
2012年 | 1282篇 |
2011年 | 1316篇 |
2010年 | 732篇 |
2009年 | 706篇 |
2008年 | 1062篇 |
2007年 | 1006篇 |
2006年 | 1022篇 |
2005年 | 903篇 |
2004年 | 865篇 |
2003年 | 710篇 |
2002年 | 688篇 |
2001年 | 129篇 |
2000年 | 95篇 |
1999年 | 123篇 |
1998年 | 124篇 |
1997年 | 111篇 |
1996年 | 84篇 |
1995年 | 76篇 |
1994年 | 68篇 |
1993年 | 45篇 |
1992年 | 57篇 |
1991年 | 41篇 |
1990年 | 35篇 |
1989年 | 44篇 |
1988年 | 46篇 |
1987年 | 32篇 |
1986年 | 29篇 |
1985年 | 22篇 |
1984年 | 18篇 |
1983年 | 18篇 |
1982年 | 14篇 |
1975年 | 15篇 |
1974年 | 14篇 |
1972年 | 13篇 |
1971年 | 13篇 |
1970年 | 18篇 |
1969年 | 14篇 |
1968年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Aneurysm of the abdominal aorta in an eighteen-month-old child 总被引:1,自引:0,他引:1
Jean Olivier Defraigne MD Jean Pierre Paquot MD Etienne Creemers MD Raymond MD Limet 《Annals of vascular surgery》1988,2(2):193-195
We report the case of an infected aneurysm of the abdominal aorta in a 18 month-old child, discovered by routine palpation of the abdomen during hospitalization for pneumonia. Ultrasonography and arteriography showed a 6 cm aneurysm of the abdominal aorta beginning distal to the renal arteries which occluded the right common Iliac artery. The aneurysm was treated by interposing a 6 mm Gore-Tex graft between the infrarenal aorta and the aortic bifurcation. Pathologic examination of the aneurysmal wall demonstrated a leukocytic Infiltrate and the presence of encapsulated Gram positive organisms. Arterial aneurysms are exceedingly rare in children. Their etiology is varied: infection, connective tissue disease, trauma, inflammatory arterial disease or other rare diseases such as tuberous sclerosis, neurofibromatosis, or Beçhet’s disease. 相似文献
42.
A central paradox of tuberculosis immunity is that reinfection and bacterial persistence occur despite vigorous host immune responses concentrated in granulomas, which are organized structures that form in response to infection. Prevailing models attribute reinfection and persistence to bacterial avoidance of host immunity via establishment of infection outside primary granulomas. Alternatively, persistence is attributed to a gradual bacterial adaptation to evolving host immune responses. We show here that superinfecting Mycobacterium marinum traffic rapidly into preexisting granulomas, including their caseous (necrotic) centers, through specific mycobacterium-directed and host cell-mediated processes, yet adapt quickly to persist long term therein. These findings demonstrate a failure of established granulomas, concentrated foci of activated macrophages and antigen-specific immune effector cells, to eradicate newly deposited mycobacteria not previously exposed to host responses. 相似文献
43.
In vitro experiments were performed on brainstem – spinal cord preparations from mouse neonates to compare the noradrenergic regulations of the respiratory network in the control C3H/HeJ strain and the transgenic Tg8 strain which has been created from the C3H/HeJ strain by deletion of the gene encoding monoamine oxidase A (MAOA), the main enzyme for serotonin degradation. In both control and MAOA-deficient strains, we show: (i) that the pontine A5 area exerts a potent inhibitory modulation on the respiratory rhythm generator; (ii) that noradrenaline application induces a tonic phrenic activity; and (iii) that noradrenaline increases the respiratory rhythm. The latter effect is however delayed and weak in the Tg8 strain. Therefore, MAOA-deficiency has only slightly altered the noradrenergic regulations of the respiratory network. 相似文献
44.
Etienne O Gasnier C Taddei C Voegel JC Aunis D Schaaf P Metz-Boutigue MH Bolcato-Bellemin AL Egles C 《Biomaterials》2005,26(33):6704-6712
The surface of medical devices is a common site of bacterial and fungal adhesion, first step to the constitution of a resistant biofilm leading frequently to chronic infections. In order to prevent such complications, several physical and chemical modifications of the device surface have been proposed. Here, we experiment a new type of topical antifungal coating using the layer-by-layer technique. The nanometric multilayer film obtained by this technique is functionalized by the insertion of a chromogranin A-derived antifungal peptide (CGA 47-66, chromofungin). We show that the embedded peptide keeps its antifungal activity by interacting with the fungal membrane and penetrating into the cell. In vitro studies demonstrate that such an antifungal coating is able to inhibit the growth of yeast Candida albicans by 65% and completely stop the proliferation of filamentous fungus Neurospora crassa. The cytotoxicity of such a coating was also assessed by growing human gingival fibroblasts at its surface. Finally, the antifungal coating of poly(methylmethacrylate), a widely used material for biomedical devices, is successfully tested in an in vivo oral candidiasis rat model. Taken together, these results assessed the functionalized multilayer films containing a new potent antifungal non-toxic peptide, as a novel and promising technique for local antifungal protection. 相似文献
45.
46.
Schleiermacher G Raynal V Janoueix-Lerosey I Combaret V Aurias A Delattre O 《Genes, chromosomes & cancer》2004,39(2):143-150
In neuroblastoma, the most frequent genetic alteration is gain of chromosome arm 17q, which arises from unbalanced translocations. To document these genetic events more precisely, we performed an extensive study of chromosome 17 breakpoints in 27 neuroblastoma cell lines by using a combination of fluorescence in situ hybridization mapping with BAC/PAC clones and allele analysis with polymorphic markers. All cases exhibited one or more unbalanced chromosome 17 translocations, and 15 distinct breakpoint regions could be mapped. This high variability indicates that gene fusion or disruption events are extremely unlikely to account for the underlying oncogenic role of these translocations. However, breakpoints were not randomly distributed, most of them mapping to the proximal part of 17q. As a result of translocations, all cell lines but one exhibited gain of the 53.5 Mb-->qter fragment, bordered proximally by the clone CTC-462L7. The most telomeric breakpoint, flanked by the clone RP11-443M10, defined the 70.9 Mb-->qter fragment as a region of additional gain. In addition to chromosome gains, loss of heterozygosity for the short arm of chromosome 17 was observed in close to half the cases. It was either related to a chromosome 17 monosomy or to a uniparental isodisomy. Finally, in cases with a single normal chromosome 17, we show that the parental origin of the translocated chromosome 17 can be either distinct or identical to that of the normal chromosome. Similarly, multiple translocations within the same cell line can either involve the same or different chromosome 17 homologues, indicating the likely absence of parental origin bias in the generation of these alterations. 相似文献
47.
Structure of four amplified DNA novel joints 总被引:8,自引:0,他引:8
Edith Legouy Nicole Fossar Guy Lhomond Olivier Brison 《Somatic Cell and Molecular Genetics》1989,15(4):309-320
The structures of four novel joints present in the amplified DNA of a Syrian hamster cell line highly resistant to N-(phosphonacetyl)-l-aspartate were analyzed. Novel joints J1, J2, and J4 were formed by recombination between two regions of wild-type DNA, whereas joint J3 is the end point of an inverted duplication. A fraction of the J3 copies displays a cruciform structure in the purified genomic DNA. The formation of J1 and J2 apparently involved a simple breakage and joining of the two wild-type sequences, whereas extra nucleotides are present at the junction point of J3 and J4. The two regions of the wild-type DNA which have recombined to form J1, J2, and J4 show few sequence similarities, indicating that these joints probably resulted from nonhomologous recombination. AT-rich regions are present in the vicinity of the breakpoint for the four joints and eight of 10 crossover points could be associated with putative topoisomerase I cleavage sites. Our results indicate that different types of novel joints are present in the amplified DNA of this cell line, which was isolated after several steps of selection. 相似文献
48.
Fawzia Zeraria Olivier Dry Jacqueline Fischer Yveline Frobert Jean-Yves Couraud Marie Conrath 《Journal of chemical neuroanatomy》1995,9(1):65-77
A monoclonal antibody directed against a peptide (PS5) specified by RNA complementary to the mRNA coding for substance P (SP), was used to label SP receptors in the rat spinal cord as demonstrated by light and electron microscopy. An immunocytochemical method (avidin-biotin-peroxidase) was used on vibratome sections from rats perfused with paraformaldehyde. Immunoreactivity was observed principally in the two superficial layers of the dorsal horn, in lamina X and the region of motoneurons. The labeling was absent when the antibody was preincubated with the complementary peptide (PS5) used as immunogen. Competition between the anti-complementary peptide antibody and different ligands was tested by preincubation of tissue sections with the ligand in the presence of peptidase inhibitors before addition of the antibody. A specific agonist (SP) or antagonist (spantide, RP 67580) at 10−6M led to total absence of labeling. These results indicate that under our experimental conditions, the anti-complementary peptide antibody recognizes a SP binding site in the rat spinal cord. Electron microscopic study of the two superficial laminae of the dorsal horn showed that immunolabeling was mainly localized extracellularly at apposing neuronal plasma membranes. It was mostly associated with axodendritic or axosomatic appositions. Occasionally labeling was observed between two axon terminals. In all cases, these appositions were non junctional. Generally, neuronal processes involved in these appositions did not contain large granular vesicles. These observations suggest that SP may act in a diffuse, nonsynaptic manner probably on targets distant from SP release sites. 相似文献
49.
Seventeen mycotoxins [aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG2),G2 (AFG2), aflatoxicol, sterigmatocystin, patulin, citrinin,penicillic acid, T-2 toxin, diacetoxyscirpenol, zeara-lenone,zearalenol ( and ß isomers 1:1), ochratoxin A, norso-lorinicacid, averufin, versicolorin A] were tested using the SOS Chromotest(PQ37 and PQ35). Six of the mycotoxins (AFB1, AFG1, AFB2, aflatoxicol,sterigmatocystin and versicolorin A) were genotoxic on PQ37strain with and without metabolic activation. The results obtainedwith metabolic activation are in agreement with positive resultsobtained in other tests of genotoxicity. Except for AFB2, thepresence of a double bond C8C9 in the dihydrobenzofurane(DHBF) ring explained the activity due to the formation of anepoxide, but the coumarin cyclopentenone ring also plays a rolein the qualitative differences of genotoxic activity. The wild-typeuvrB gene in PQ35 decreases the genotoxic response with andwithout metabolic activation. Without metabolic activation,only mycotoxins possessing the DHBF ring group and double linkageC8C9 exhibit a genotoxic effect.
3To whom correspondence should be addressed 相似文献
50.
Louis Journeau Marc-Antoine Pistorius Ulrique Michon-Pasturel Marc Lambert Francois-Xavier Lapébie Alessandra Bura-Riviere Philippe de Faucal Patrick Jego Quentin Didier Cécile Durant Geoffrey Urbanski Baptiste Hervier Claire Toquet Christian Agard Olivier Espitia 《Autoimmunity reviews》2019,18(5):476-483