全文获取类型
收费全文 | 6097篇 |
免费 | 450篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 136篇 |
妇产科学 | 136篇 |
基础医学 | 1175篇 |
口腔科学 | 98篇 |
临床医学 | 513篇 |
内科学 | 1525篇 |
皮肤病学 | 185篇 |
神经病学 | 615篇 |
特种医学 | 85篇 |
外科学 | 573篇 |
综合类 | 26篇 |
一般理论 | 3篇 |
预防医学 | 455篇 |
眼科学 | 84篇 |
药学 | 501篇 |
中国医学 | 21篇 |
肿瘤学 | 427篇 |
出版年
2024年 | 5篇 |
2023年 | 91篇 |
2022年 | 222篇 |
2021年 | 406篇 |
2020年 | 195篇 |
2019年 | 269篇 |
2018年 | 295篇 |
2017年 | 191篇 |
2016年 | 228篇 |
2015年 | 230篇 |
2014年 | 310篇 |
2013年 | 353篇 |
2012年 | 496篇 |
2011年 | 526篇 |
2010年 | 275篇 |
2009年 | 233篇 |
2008年 | 366篇 |
2007年 | 361篇 |
2006年 | 317篇 |
2005年 | 305篇 |
2004年 | 241篇 |
2003年 | 218篇 |
2002年 | 206篇 |
2001年 | 26篇 |
2000年 | 11篇 |
1999年 | 34篇 |
1998年 | 29篇 |
1997年 | 25篇 |
1996年 | 15篇 |
1995年 | 16篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1968年 | 2篇 |
排序方式: 共有6598条查询结果,搜索用时 31 毫秒
21.
Galectin-3, fibronectin-1, CITED-1, HBME1 and cytokeratin-19 immunohistochemistry is useful for the differential diagnosis of thyroid tumors. 总被引:7,自引:0,他引:7
Manju L Prasad Natalia S Pellegata Ying Huang Haikady N Nagaraja Albert de la Chapelle Richard T Kloos 《Modern pathology》2005,18(1):48-57
The diagnosis of thyroid tumors is critical for clinical management; however, tumors with follicular architecture often present problems. We evaluated the diagnostic use of the protein expression of four genes that were found to be upregulated in papillary thyroid carcinoma compared to normal thyroid (LGALS3, FN1, CITED1 and KRT19), and of the mesothelial cell surface protein recognized by monoclonal antibody HBME1 in thyroid tumors. Tissues from 85 carcinomas (67 papillary, six follicular, eight Hürthle cell and four anaplastic) and 21 adenomas were evaluated by immunohistochemistry for the expression of these gene protein products, for example, galectin-3 (GAL3), fibronectin-1 (FN1), CITED1, cytokeratin-19 (CK19) and HBME1. Non-neoplastic thyroids (29 adenomatous and 14 thyrotoxic hyperplasia, and 59 normal) were also studied. The expression of all five proteins was significantly associated with malignancy, and highly specific (> or = 90%) for carcinoma compared to adenoma. GAL3, FN1 and/or HBME1 expression was seen in 100% of carcinomas (85/85) and in 24% of adenomas (5/21). Coexpression of multiple proteins was seen in 95% of carcinomas and only 5% of adenomas (P<0.0001). Coexpression of FN1 and GAL3 (FN1+ GAL3+, 70/85) or FN1 and HBME1 (FN1+ HBME1+, 53/85) was restricted to carcinomas, while their concurrent absence (FN1- GAL3- or FN1- HBME1-, 18/21 adenoma) was highly specific (96%) for benign lesions. Among non-neoplastic thyroids, adenomatous hyperplasia frequently expressed GAL3 (n=16), CK19 (n=9) and CITED1 (n=7), but the expression was predominantly focal in contrast to the diffuse expression in carcinomas. An immunohistochemical panel consisting of GAL3, FN1 and HBME1 may be useful in the diagnosis of follicular cell-derived thyroid tumors. 相似文献
22.
23.
Oleg A. Ivashkevich Pavel. N. Gaponik Tamara B. Kovalyova Nonna I. Makarevich Natalia I. Sushko 《Macromolecular chemistry and physics.》1992,193(6):1369-1376
Three novel monomers: 2-ethyl-, 2-isopropyl- and 2-tert-butyl-5-vinyltetrazole were synthesized. The copolymerizations of these monomers and 2-methyl-5-vinyltetrazole with styrene and methyl methacrylate were examined and the corresponding reactivity ratios r1, r2 and the Alfrey-Price Q, e values estimated. The obtained results, together with IR, 1H NMR and 13C NMR data and quantum-chemical calculations of vinyltetrazole molecules by the AM-1 method, indicate that the type and the size of the substituent does not essentially influence the reactivity of 2-alkyl-5-vinyltetrazoles in radical copolymerization with vinyl monomers. 相似文献
24.
Over the last decade, we have witnessed an explosion of information regarding the function of glycoconjugates, carbohydrate-binding proteins, and the elucidation of the sugar code. This progress has yielded not only important insights into fundamental areas of glycobiology but has also influenced other fields such as immunology and molecular medicine. A family of galactoside-binding proteins, called galectins, has emerged recently as a novel kind of bioactive molecules with powerful, immunoregulatory functions. Different members of this family have been shown to modulate positively or negatively multiple steps of the inflammatory response, such as cell-matrix interactions, cell trafficking, cell survival, cell-growth regulation, chemotaxis, and proinflammatory cytokine secretion. To introduce a comprehensive overview of these new advances, here we will explore the molecular mechanisms and biochemical pathways involved in these functions. We will also examine the role of these proteins in the modulation of different pathological processes, such as chronic inflammation, autoimmunity, infection, allergic reactions, and tumor spreading. Understanding the intimate mechanisms involved in galectin functions will help to delineate selective and novel strategies for disease intervention and diagnosis. 相似文献
25.
Cell polarity is manifest along the animal/vegetal axis in eggs of the frog, Xenopus laevis. Along this axis, maternal cytoplasmic components are asymmetrically distributed and are thought to underlie specification of distinct cell fates. To ascertain the molecular identities of such cytoplasmic components, we have used a monoclonal antibody that specifically stains the vegetal hemisphere of Xenopus eggs. The antigenic protein Vp67 (vegetal protein of 67 kDa) was identified through purification and cloning as a Xenopus homolog of the mitochondrial protein dihydrolipoamide acetyltransferase, a component of the pyruvate dehydrogenase complex. The identification of Vp67 as a mitochondrial protein could indicate that populations of mitochondria are asymmetrically distributed in Xenopus eggs. 相似文献
26.
Mutations of the GREAT gene cause cryptorchidism 总被引:7,自引:0,他引:7
Gorlov IP Kamat A Bogatcheva NV Jones E Lamb DJ Truong A Bishop CE McElreavey K Agoulnik AI 《Human molecular genetics》2002,11(19):2309-2318
In humans, failure of testicular descent (cryptorchidism) is one of the most frequent congenital malformations, affecting 1-3% of newborn boys. The clinical consequences of this abnormality are infertility in adulthood and a significantly increased risk of testicular malignancy. Recently, we described a mouse transgene insertional mutation, crsp, causing high intraabdominal cryptorchidism in homozygous males. A candidate gene Great (G-protein-coupled receptor affecting testis descent), was identified within the transgene integration site. Great encodes a seven-transmembrane receptor with a close similarity to the glycoprotein hormone receptors. The Great gene is highly expressed in the gubernaculum, the ligament that controls testicular movement during development, and therefore may be responsible for mediating hormonal signals that affect testicular descent. Here we show that genetic targeting of the Great gene in mice causes infertile bilateral intraabdominal cryptorchidism. The mutant gubernaculae fail to differentiate, indicating that the Great gene controls their development. Mutation screening of the human GREAT gene was performed using DHPLC analysis of the genomic DNA from 60 cryptorchid patients. Nucleotide variations in GREAT cDNA were found in both the patient and the control populations. A unique missense mutation (T222P) in the ectodomain of the GREAT receptor was identified in one of the patients. This mutant receptor fails to respond to ligand stimulation, implicating the GREAT gene in the etiology in some cases of cryptorchidism in humans. 相似文献
27.
Vermeesch JR Melotte C Salden I Riegel M Trifnov V Polityko A Rumyantseva N Naumchik I Starke H Matthijs G Schinzel A Fryns JP Liehr T 《European journal of medical genetics》2005,48(3):319-327
A dysmorphic patient was shown to carry a small supernumerary marker chromosome. Multicolor, centromere-multicolor and regular FISH experiments proved the marker to be an analphoid 12pter derived isochromosome. Microdissection of the marker followed by reverse painting and array CGH analysis showed that the isochromosome contains approximately 6 Mb of 12pter-12p13.31 derived sequence. This is only the second report of a marker with a neocentromere 12pter and the molecular fine mapping of the duplicated region further refines the 12p region defining the Pallister-Killian syndrome phenotype. In addition, we show the feasibility of using microdissected chromosomes or chromosomal fragments to molecularly map the chromosomal breakpoints on array CGH. This technology may aid in the identification of chromosomal translocation breakpoints. 相似文献
28.
This study chronicles an at-risk mother's experience in an alternative foster care program. Influenced by attachment theory, the Children's Ark reunited children with their mothers in a supervised home environment while also providing residential support, intensive therapy, and education. After losing custody of her infant Kindra, 18-year-old Anna participated in the Ark for 2 years, after which she regained custody of Kindra. We assessed Anna and Kindra at multiple times using a variety of instruments, including a semi-structured interview, the Adult Attachment Interview, and the Strange Situation procedure. Anna moved from a profoundly insecure state of mind to a secure one, while Kindra moved from a resistant to a secure attachment. Qualitative analyses of Anna's interviews documented growth in her capacity to use the important relationships at the Ark as secure bases and to welcome rather than fear intimacy with Kindra. The qualitative analyses also described growth in Anna's capacities for reflective functioning and positive changes in her internal working model. We conclude with an analysis of the process of change from the perspective of attachment theory. 相似文献
29.
Mahmutefendić H Kucić N Lucin P 《American journal of reproductive immunology (New York, N.Y. : 1989)》2002,48(2):87-95
PROBLEM: To characterize the constitutive internalization of major histocompatibility complex (MHC) class I molecules, we have studied the expression of completely conformed (full) and unconformed (empty) L(d) molecules on non-polarized murine P815 cells. METHODS OF STUDY: Spontaneous endocytosis of L(d) molecules was induced by cycloheximide, an inhibitor of protein synthesis, and their disappearance from the cell surface was determined by flow cytometry. In order to investigate the mechanism of internalization, a palette of inhibitors of endocytosis and vesicular transport was used. RESULTS: Inhibitors of clathrine endocytosis did not influence the internalization of L(d) molecules. Inhibitors of caveolar endocytosis and inhibitors of endolysosomal degradation prevented down-regulation of empty, but not of full L(d) molecules. CONCLUSIONS: Empty L(d) molecules are internalized mostly by caveolar endocytosis and full L(d) molecules use a different pathway, neither clathrine-mediated nor caveolar. After internalization, full L(d) molecules are probably degraded and empty L(d) molecules recycle between endosomal compartment and the cell surface before they enter into the degradation compartment. 相似文献
30.