全文获取类型
收费全文 | 14520篇 |
免费 | 644篇 |
国内免费 | 104篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 310篇 |
妇产科学 | 184篇 |
基础医学 | 1982篇 |
口腔科学 | 202篇 |
临床医学 | 775篇 |
内科学 | 3707篇 |
皮肤病学 | 477篇 |
神经病学 | 1010篇 |
特种医学 | 830篇 |
外科学 | 2868篇 |
综合类 | 63篇 |
一般理论 | 2篇 |
预防医学 | 312篇 |
眼科学 | 209篇 |
药学 | 697篇 |
中国医学 | 26篇 |
肿瘤学 | 1537篇 |
出版年
2023年 | 70篇 |
2022年 | 139篇 |
2021年 | 282篇 |
2020年 | 192篇 |
2019年 | 209篇 |
2018年 | 259篇 |
2017年 | 251篇 |
2016年 | 341篇 |
2015年 | 331篇 |
2014年 | 459篇 |
2013年 | 534篇 |
2012年 | 747篇 |
2011年 | 850篇 |
2010年 | 565篇 |
2009年 | 480篇 |
2008年 | 880篇 |
2007年 | 897篇 |
2006年 | 934篇 |
2005年 | 923篇 |
2004年 | 864篇 |
2003年 | 798篇 |
2002年 | 884篇 |
2001年 | 232篇 |
2000年 | 228篇 |
1999年 | 244篇 |
1998年 | 254篇 |
1997年 | 192篇 |
1996年 | 223篇 |
1995年 | 186篇 |
1994年 | 149篇 |
1993年 | 131篇 |
1992年 | 173篇 |
1991年 | 153篇 |
1990年 | 143篇 |
1989年 | 133篇 |
1988年 | 116篇 |
1987年 | 109篇 |
1986年 | 80篇 |
1985年 | 79篇 |
1984年 | 75篇 |
1983年 | 51篇 |
1982年 | 48篇 |
1981年 | 47篇 |
1980年 | 49篇 |
1979年 | 50篇 |
1978年 | 28篇 |
1977年 | 29篇 |
1976年 | 19篇 |
1974年 | 21篇 |
1971年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
R Würzner K Tokunaga R Nitze O G?tze P J Lachmann 《Experimental and clinical immunogenetics》1991,8(3):177-183
Two complement C7 protein polymorphisms exist. One is determined by isoelectric focussing whereas the other is determined by the reaction pattern of a monoclonal C7-allospecific antibody in an ELISA assay. C7 concentrations quantitated by an ELISA based on polyclonal C7-specific IgG and data from functional haemolytic assays were compared with the allotypes of both C7 protein polymorphisms. Testing a randomly selected Japanese population revealed that not only C7*3 but also C7*N is a hypomorphic allele. However, no significant disease association of C7*N or C7*M was found in studies of hospitalized patients. 相似文献
62.
Intracytoplasmic neuronal inclusion bodies were found in the temporal lobe of an elderly woman. The oval or rod-shaped inclusion bodies were eosinophilic, showed bright red staining with azan, and were about half the size of the nucleus of a large neuron. They were non-argyrophilic and non-congophilic. Ultrastructurally, the inclusion bodies consisted of aggregates of filamentous materials showing partial periodicity. Among inclusion bodies reported up to now, the present ones resembled some described previously as "thalamic inclusions", but were different with regard to their partial filament periodicity, and unusual in that they were located in the deep layer of the temporal lobe and not in the thalamic nuclei. 相似文献
63.
Tatsuo Ushiki Osamu Ohtani Kazuhiro Abe 《Anatomical record (Hoboken, N.J. : 2007)》1995,241(1):113-122
Background: The reticular framework in the lymph node has in the past been studied mainly by light microscopy of silver-impregnated specimens. The aim of the present study is to understand three-dimensionally the ultrastructure and organization of the reticular framework better than before. Methods: The mesenteric lymph nodes of the rat were prepared either an alkali-water maceration method or a conventional method and were observed in a scanning electron microscope (SEM). Results: The SEM study of alkali-water macerated tissues visualized directly the reticular fiber network in the lymph node. The reticular fibers consisted of thin bundles of collagem fibrils. They were continuous with the collagen fibriliar sheaths of blood vessels and lymphatic sinuses as well as with the fibrous capusule, thus acting as a skeleton of the lymph node. The arrangement of the reticulum was variable, depending on individual compartments. The SEM study of conventionally treated tissues, on the other hand, clarified the shape of reticular cells and their relationship with the reticular fibers. The sinus reticular cells connected with the sinus lining cells but separated from the parenchymal reticular cells, indicating that the former two originate from lymphatic endothelial cells. The parenchymal reticular cells varied in shape depending on their locations but essentially shared features with fibroblasts. Conclusions: The arrangements of the reticular fibers in the parenchyma were closely related to the associated reticular cells, showing the possibility that the reticular cells maintain the shape of the reticular framework suitable for each compartment of the lymph node. © 1995 Wiley-Liss, Inc. 相似文献
64.
K. Matsuki T. Juji K. Tokunaga M. Mochizuki K. Hayashi Y. Fujino J. Numaga H. Yamashita 《Tissue antigens》1987,29(4):208-213
HLA class I, II, and III antigens were studied in Japanese patients with Beh?et's disease with refractory ocular attacks. In addition to the increased frequency of B51, DQw3, especially TA10-negative DQw3, was increased and DQw1 was decreased significantly in this subgroup of Beh?et's disease. As for complement markers, C4A Q0 was increased. A rare variant of BF S07 was first observed in Japanese. Although the mechanism for the DQw3 association is obscure, a possible hypothesis is that an immune-response or immune-suppression gene linked to the DQ antigens modulates the disease severity and the efficacy of treatments. 相似文献
65.
S. Kawai S. Maekawajiri K. Tokunaga K. Kashiwase M. Miyamoto T. Akaza T. Juji A. Yamane 《International journal of immunogenetics》1996,23(6):471-486
We describe HLA-DRB1 typing using polymerase chain reaction-based microtitre plate hybridization (PCR-MPH), which can process large numbers of samples. MPH typing is similar to an enzyme-linked immunosorbent assay (ELISA), in which a tandemly ligated sequence-specific oligonucleotide is immobilized on microtitre wells. The typing procedure consisted of two steps. In the first, PCR-MPH with 16 probes was performed to determine the specificities of the serological levels (DR1, DR2, DR3, DR4, DR11, DR12, DR13, DR14, DR7, DR8, DR9 and DR10) after generic amplification (‘low resolution typing’). In the second step, DR1, DR2, DR4, DR 12/8 and DR3/11/13/14 were group-specifically amplified based on the results of the first PCR-MPH, and microtitre plate hybridization proceeded in a similar manner to the first step (‘high resolution typing’). Low resolution typing was completed within 2 h after generic amplification, and the results of high resolution typing were obtained in another 3.5 h after amplification. The allelic types classified using PCR-MPH were completely concordant with those obtained by PCR- single-strand conformation polymorphism or PCR-restriction fragment length polymorphism. 相似文献
66.
The aim of the present study is to demonstrate the cellular basis of 5'-nucleotidase (5'-Nase) activity in the greater omentum of rats. Enzyme histochemistry for 5'-Nase showed that lymphatic vessels in the omentum as well as lymphocytes in the milky spots were positively stained. Electron microscopic observation revealed-5'-Nase activity at the luminal surface of the lymphatic endothelial cells, pinocytotic vesicles in the endothelial cells and the surface of fibroblasts located at the intercellular space of adipose cells. Fibroblasts extended long cytoplasmic processes toward adipose cells and inflammatory cells. These findings suggest that lymphatic endothelial cells as well as fibroblasts in the omentum may play an important role in regulation of metabolism and immune mechanisms in the greater omentum by supplying adenosin. 相似文献
67.
Studies suggested that experimental autoimmune diseases can effectively be prevented and treated by application of normal autoreactive T cells or autoreactive T cells in an attenuated form. In this study, several autoreactive CD4- CD8- T-cell clones (A2, A6, and A13 cells) were isolated for the first time from the draining lymph nodes of Lewis rats with adjuvant arthritis (AA). Surprisingly, intraperitoneal inoculation with A13 cells, but not A2 or A6 cells protected rats from AA both clinically and histologically. It was demonstrated that A13 cells were CD4- CD8- alpha beta T cells, and showed proliferative responses to irradiated syngeneic spleen cells (antigen-presenting cells; APC). Interestingly, A13 cells proliferated against concanavalin A (Con A) and staphylococcal enterotoxin B (SEB), but did not show any proliferation to Mycobacterium tuberculosis (Mt), or its 65 000 MW heat-shock protein (HSP). Rats protected from AA by inoculation with A13 cells showed a specific anti-idiotypic delayed-type hypersensitivity reaction compared with other autoreactive T cells (A2 or A6 cells). These findings demonstrate that AA can be suppressed by autoreactive CD4- CD8- alpha beta T cells, and these cells may be used as therapeutic agents in experimental autoimmunity. 相似文献
68.
69.
Rika A. Furuta Hiroyuki Sakai Meiko Kawamura Kenzo Tokunaga Masakazu Hatanaka Dr. Akio Adachi 《Virus genes》1995,11(1):11-14
Studies on functional compatibility of various Rev proteins derived from all known human and simian immunodeficiency virus subgroups have shown that this essential gene product is not always exchangeable among the viruses. In an attempt to map the region of Rev proteins responsible for the observed nonreciprocal complementation, hybrid genomic Rev expression vectors were constructed by exchanging the first and second exons ofrev genes, and were examined for their abilities to activate reporter clones by transfection. With one exception, the second coding exon ofrev gene determined the functional specificity of Rev proteins. 相似文献
70.