全文获取类型
收费全文 | 13373篇 |
免费 | 678篇 |
国内免费 | 81篇 |
专业分类
耳鼻咽喉 | 108篇 |
儿科学 | 294篇 |
妇产科学 | 195篇 |
基础医学 | 1613篇 |
口腔科学 | 286篇 |
临床医学 | 861篇 |
内科学 | 3826篇 |
皮肤病学 | 122篇 |
神经病学 | 834篇 |
特种医学 | 411篇 |
外科学 | 1952篇 |
综合类 | 58篇 |
预防医学 | 358篇 |
眼科学 | 341篇 |
药学 | 1326篇 |
中国医学 | 22篇 |
肿瘤学 | 1525篇 |
出版年
2023年 | 93篇 |
2022年 | 212篇 |
2021年 | 286篇 |
2020年 | 149篇 |
2019年 | 228篇 |
2018年 | 272篇 |
2017年 | 228篇 |
2016年 | 263篇 |
2015年 | 299篇 |
2014年 | 318篇 |
2013年 | 454篇 |
2012年 | 762篇 |
2011年 | 856篇 |
2010年 | 488篇 |
2009年 | 411篇 |
2008年 | 710篇 |
2007年 | 797篇 |
2006年 | 754篇 |
2005年 | 723篇 |
2004年 | 719篇 |
2003年 | 761篇 |
2002年 | 689篇 |
2001年 | 351篇 |
2000年 | 321篇 |
1999年 | 314篇 |
1998年 | 169篇 |
1997年 | 134篇 |
1996年 | 110篇 |
1995年 | 108篇 |
1994年 | 82篇 |
1993年 | 102篇 |
1992年 | 183篇 |
1991年 | 149篇 |
1990年 | 168篇 |
1989年 | 182篇 |
1988年 | 170篇 |
1987年 | 145篇 |
1986年 | 149篇 |
1985年 | 138篇 |
1984年 | 88篇 |
1983年 | 64篇 |
1982年 | 48篇 |
1981年 | 28篇 |
1980年 | 39篇 |
1979年 | 49篇 |
1978年 | 35篇 |
1977年 | 38篇 |
1974年 | 31篇 |
1973年 | 33篇 |
1972年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Transcriptome analysis of hagfish leukocytes: a framework for understanding the immune system of jawless fishes 总被引:1,自引:0,他引:1
Suzuki T Shin-I T Kohara Y Kasahara M 《Developmental and comparative immunology》2004,28(10):993-1003
Jawless fishes occupy a critical phylogenetic position in understanding the origin of the adaptive immune system. Here, we performed large-scale expressed sequence tag analysis of leukocytes isolated from the inshore hagfish Eptatretus burgeri. Although we found many immunity-related genes such as those involved in lymphocyte or hematopoietic cell signaling and development as well as cytokine and cytokine receptor genes, MHC molecules or antigen receptors were not identified. We characterized two hagfish cDNAs that closely resembled mammalian proteins with essential roles in adaptive immunity, one encoding a GATA3-like molecule and another encoding a Bruton's tyrosine kinase (Btk)-like molecule. The GATA3-like gene of hagfish was equidistant from GATA3 and GATA2 in jawed vertebrates. Similarly, the hagfish Btk-like molecule was not Btk itself, but qualified as a pre-duplicated form of Btk and Bmx in jawed vertebrates. In total, our work provides circumstantial evidence that adaptive immunity is unique to jawed vertebrates. 相似文献
52.
Immunogenetic analysis of gastric MALT lymphoma-like lesions induced by Helicobacter pylori infection in neonatally thymectomized mice 总被引:3,自引:0,他引:3
Fukui T Okazaki K Tamaki H Kawasaki K Matsuura M Asada M Nishi T Uchida K Iwano M Ohana M Hiai H Chiba T 《Laboratory investigation; a journal of technical methods and pathology》2004,84(4):485-492
Most gastric mucosa-associated lymphoid tissue (MALT) lymphomas are caused by Helicobacter pylori (H. pylori) infection. We previously reported that acquired lymphoid follicles with germinal centers were induced by H. pylori infection in neonatally thymectomized (nTx) mice. In the present study, we developed gastric MALT lymphoma-like lesions in nTx mice by long-term H. pylori infection, and performed immunogenetic analyses. BALB/c mice were thymectomized on the 3rd day after birth. At 6 weeks of age, mice were orally infected with 10(8) H. pylori and serially killed 2, 4, 6, and 12 months later. Normal BALB/c and noninfected nTx mice served as controls. Follicle formation occurred after 2 months of H. pylori infection in the nTx mice. Follicle formation and infiltration of intraepithelial lymphocytes progressed in a time-dependent manner. Lymphoepithelial lesions, a characteristic feature of MALT lymphoma, also occurred in a time-dependent manner (100% at 12 months). Serum immunoelectrophoresis revealed a monoclonal band (M-protein) in 30% (3/10) of mice 6 months after infection. M-protein-positive mice had amplification of one or two IgM and/or IgG heavy-chain genes in the gastric B lymphocytes, as determined with polymerase chain reaction, suggesting mono- or oligoclonality. Overexpression of Bcl-X(L) protein was immunohistologically observed in the infiltrating B lymphocytes and in some follicular B lymphocytes in 80% (8/10) of the cases at 12 months. Thus, H. pylori infection is involved in the development of gastric MALT lymphoma-like lesions in nTx mice. Our mouse model is useful for clarifying the pathogenetic mechanism of gastric MALT lymphoma by H. pylori infection. 相似文献
53.
54.
Satoko Arai Yuka Shinohara Yasuyuki Kato Satoshi Hirano Atsuto Yoshizawa Masaaki Hojyo Nobuyuki Kobayashi Haruhito Sugiyama Koichiro Kudo 《Arerugī》2007,56(10):1293-1297
A 51-year-old man was admitted to our hospital with fever, dry cough and dyspnea. He had taken minocycline for 11 days because of urinary tract infection. Chest X-ray on admission showed diffuse reticular shadows in bilateral lung fields with bilateral pleural effusion. Cessation of minocycline led to spontaneous improvement of symptoms and radiographic findings. The lymphocyte stimulation test for minocycline with peripheral blood and pleural effusion were negative. After provocation test with minocycline, he developed fever and dry cough and bilateral ground glass opacity appeared on his chest X-ray. He was diagnosed as minocycline-induced pneumonitis and recovered rapidly following corticosteroid therapy. 相似文献
55.
Presynaptic dendrites (PSDs) which participate in the serial synapses have frequently been found in the intermediate and deep layers of the cat superior colliculus. The PSDs are presynaptic to small dendritic shafts or spines with symmetrical membrane thikening, and postsynaptic to axon terminals with asymmetrical synaptic contact. Two types of the axon terminals are observed, both of which contain pleomorphic vesicles. 相似文献
56.
57.
Suzuki M Okuyama T Yoshikawa K Yamaoka Y Ariyasu T Fujita M Tankawa H Sugiyama T Takahashi R 《Pathology international》1996,46(1):46-53
Overexpression of p53 protein, epidermal growth factor receptor (EGF-R), and c-erbB-2 protein was assessed by immunohistochemical staining of formalin-fixed, paraffin-embedded tissue from 64 invasive breast tumors. The correlation between abnormal expression of each protein and various disease parameters, including lymph node metastasis and histopathologic type and grade was analyzed. Despite the previous proposal, no significant correlation was found between lymph node metastases and overexpression of each gene in the primary tumors. In addition, some metastatic lesions did not always exhibit overexpression, even if it was evident in the primary tumors. Overexpression of c-erbB-2 protein correlated well with Bloom's histological grading. p53 expression was detected most often in tumors with hyperchromatism and more frequent mitosis. Overexpression of c-erbB-2 protein occurred more frequently in p53-positive tumors. The results indicate that abnormal expression of p53 protein causes genetic instability in the early stage of tumor development, resulting in subsequent overexpression of other oncogenes. 相似文献
58.
Kuroiwa K Li H Tago K Iwahana H Yanagisawa K Komatsu N Oshikawa K Sugiyama Y Arai T Tominaga SI 《Hybridoma》2000,19(2):151-159
The human ST2 gene can be specifically induced by growth stimulation in fibroblastic cells, and can also be induced by antigen stimulation in Th2 cells. The gene encodes a soluble secreted protein, ST2, and a transmembrane protein, ST2L, which are closely related to the interleukin-1 receptor. To gain insight into the biological roles of the ST2 gene, three monoclonal antibodies (MAbs) against human ST2 gene products were obtained. To obtain these antibodies, immunization was carried out using two different immunogens: purified soluble human ST2 protein (hST2), and COS7 cells, which express the extracellular portion of human ST2L. 2A5 and FB9 MAbs were derived from the immunization with soluble hST2, and HB12 was derived from the COS7 cell immunization. All three antibodies were shown to detect native forms of the human ST2 gene products by immunoprecipitation, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). In the competitive ELISA using biotinylated and nonlabelled MAbs, neither FB9 nor HB12 affected the binding of 2A5 to ST2 gene products. Based on this result, we constructed a sandwich ELISA system using 2A5 and FB9 to measure the concentration of soluble hST2 in sera. The ELISA, combined with the flow cytometry using these antibodies, will be a useful tool for elucidating the functions of human ST2 gene products in individuals. 相似文献
59.
Megakaryocytopoiesis in idiopathic thrombocytopenic purpura 总被引:1,自引:0,他引:1
60.
Fujita M Ishihara M Simizu M Obara K Ishizuka T Saito Y Yura H Morimoto Y Takase B Matsui T Kikuchi M Maehara T 《Biomaterials》2004,25(4):699-706
Addition of various heparinoids to the lactose-introduced, water-soluble chitosan (CH-LA) aqueous solution produces an injectable chitosan/heparinoid hydrogel. In the present work, we examined the capability of the chitosan/non-anticoagulant heparin (periodate-oxidized (IO(4)-) heparin) hydrogel to immobilize fibroblast growth factor (FGF)-2, as well as the controlled release of FGF-2 molecules from the hydrogel in vitro and in vivo. The hydrogel was biodegraded in about 20 days after subcutaneous injection into the back of a mouse. When the FGF-2-incorporated hydrogel was subcutaneously injected into the back of both mice and rats, a significant neovascularization and fibrous tissue formation were induced near the injected site. These results indicate that the controlled release of biologically active FGF-2 molecules is caused by biodegradation of the hydrogel, and that subsequent induction of the vascularization occurs. 相似文献