全文获取类型
收费全文 | 13677篇 |
免费 | 640篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 179篇 |
儿科学 | 231篇 |
妇产科学 | 188篇 |
基础医学 | 1821篇 |
口腔科学 | 389篇 |
临床医学 | 914篇 |
内科学 | 3539篇 |
皮肤病学 | 158篇 |
神经病学 | 1039篇 |
特种医学 | 690篇 |
外科学 | 2243篇 |
综合类 | 64篇 |
预防医学 | 423篇 |
眼科学 | 308篇 |
药学 | 839篇 |
中国医学 | 27篇 |
肿瘤学 | 1325篇 |
出版年
2023年 | 77篇 |
2022年 | 138篇 |
2021年 | 247篇 |
2020年 | 149篇 |
2019年 | 190篇 |
2018年 | 239篇 |
2017年 | 187篇 |
2016年 | 236篇 |
2015年 | 231篇 |
2014年 | 312篇 |
2013年 | 400篇 |
2012年 | 637篇 |
2011年 | 710篇 |
2010年 | 382篇 |
2009年 | 305篇 |
2008年 | 619篇 |
2007年 | 638篇 |
2006年 | 692篇 |
2005年 | 721篇 |
2004年 | 694篇 |
2003年 | 662篇 |
2002年 | 687篇 |
2001年 | 434篇 |
2000年 | 482篇 |
1999年 | 452篇 |
1998年 | 220篇 |
1997年 | 168篇 |
1996年 | 158篇 |
1995年 | 131篇 |
1994年 | 111篇 |
1993年 | 96篇 |
1992年 | 245篇 |
1991年 | 266篇 |
1990年 | 260篇 |
1989年 | 254篇 |
1988年 | 249篇 |
1987年 | 237篇 |
1986年 | 203篇 |
1985年 | 181篇 |
1984年 | 143篇 |
1983年 | 102篇 |
1982年 | 53篇 |
1981年 | 51篇 |
1979年 | 91篇 |
1976年 | 45篇 |
1974年 | 43篇 |
1972年 | 61篇 |
1971年 | 44篇 |
1970年 | 46篇 |
1969年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
Tomoko Kamishima Takeaki Fukuda Toshio Kakihara Yoshihisa Ohnishi Makoto Naito Hidenori Ueki Shinzo Tachikawa 《Pathology international》1993,43(10):615-623
A case of small round and spindle cell sarcoma with neuronal differentiation and oncocyte-like features is presented. The tumor was encountered in a 32 year old Japanese woman with an initial presentation of palpable tumor in the left lateral region of the thorax. The resected tumor was a partially well encapsulated whitish medullary one and consisted of small round and spindle tumor cells, together with so-called rhabdoid cells in the small round cell area. Although pseudorosettes were often observed, true rosette formation could not be detected anywhere. Ultrastructurally, despite a histologic variety of tumor cells, most tumor cells possessed numerous mitochondria, some of which occasionally contained abnormal filamentous or crystalloid structures. Various amounts of microfilaments were present in most tumor cells and microtubules were present in a few. A minority of small round cells possessed a small number of neurosecretory granules, especially in short cytoplasmic processes. A positive immunoreaction for neuron specific enolase was found by immunohistochemical examination in several small round tumor cells and for neurofilaments in lesser numbers. Despite the lack of S-100 protein, MB2 was detected in both small round and spindle cells. On the basis of these findings, the tumor of the present case corresponds to malignant peripheral nerve sheath tumor with neuronal differentiation and oncocytic features. 相似文献
82.
Koichiro Yuji Shigesaburo Miyakoshi Daisuke Kato Yuji Miura Tomohiro Myojo Naoko Murashige Yukiko Kishi Kazuhiro Kobayashi Eiji Kusumi Hiroto Narimatsu Tamae Hamaki Tomoko Matsumura Masahiro Kami Takahiro Fukuda Shigeru Masuo Kazuhiro Masuoka Atsushi Wake Junichi Ueyama Akiko Yoneyama Ko Miyamoto Haruhisa Nagoshi Michio Matsuzaki Shinichi Morinaga Yoshitomo Muto Yoichi Takeue Shuichi Taniguchi 《Biology of blood and marrow transplantation》2005,11(4):314-318
We report the results of reduced-intensity unrelated cord blood transplantation (RI-UCBT) in patients with advanced malignant lymphoma. Twenty patients (median age, 46.5 years; range, 27-66 years) underwent RI-UCBT with a preparative regimen consisting of fludarabine 125 mg/m2 , melphalan 80 mg/m 2 , and 4 Gy of total body irradiation. The median infused total cell dose was 2.75 x 10(7)/kg (range, 2.3-3.4 x 10(7)/kg). Graft-versus-host disease (GVHD) prophylaxis was composed of cyclosporine or tacrolimus alone. Fifteen patients achieved primary neutrophil engraftment after a median of 20 days. Eight patients developed grade II to IV acute GVHD, and 2 developed chronic GVHD. Of the 16 patients with evaluable disease, 10 achieved a complete response. Primary disease recurred in 1 patient, and transplant-related mortality within 100 days occurred in 8 of 20 patients. The estimated 1-year probability of progression-free survival was 50%. These data suggest that RI-UCBT is a feasible option for patients with refractory lymphoma who lack an HLA-matched donor. 相似文献
83.
Eri?WatanabeEmail author Sanae?Fukuda Taro?Shirakawa 《BMC complementary and alternative medicine》2005,5(1):21
Background
We examined a large number of healthy adults in the general community who had individually participated in a guided imagery (GI) program daily and for various durations, to examine the psychophysiological effects of a GI program within a healthy group. 相似文献84.
Phan TG Nishimura S Okame M Nguyen TA Khamrin P Okitsu S Maneekarn N Ushijima H 《Journal of medical virology》2004,74(1):173-179
A total of 236 fecal specimens collected from infants and children with gastroenteritis in Maizuru city, Japan from July 2002 to June 2003, were tested for the presence of rotaviruses, noroviruses, sapoviruses, astroviruses, and adenoviruses by RT-PCR, PAGE, RPHA, and latex agglutination methods. Among diarrheal viruses detected, group A rotavirus was the most prevalent (32.2%; 76 of 236) followed by norovirus GII (21.2%; 50 of 236), group C rotavirus (10.2%; 24 of 236), adenovirus (3.8%; 9 of 236), sapovirus (2.5%; 6 of 236), astrovirus (1.3%; 3 of 236), and norovirus GI (0.8%; 2 of 236), respectively. It is noteworthy that group C rotavirus infection was apparently confined only within the period of 5 months (December 2002 through April 2003). This pattern of infection implied that the outbreak of group C rotavirus in these patients, which was the first outbreak of gastroenteritis attributed to group C rotavirus in Maizuru city. Moreover, about half (12 of 24) of group C rotavirus infected cases were confined to infants and young children less than 3 years old. Another interesting feature of the study was the demonstration of the mixed infections with group C rotavirus and group A rotavirus, as well as group C rotavirus and norovirus GII in 20.8% (5 of 24) and 8.3% (2 of 24), respectively. This is the first report of gastroenteritis associated with the mixed infections with group C rotavirus and other viral enteropathogens such as norovirus. The results indicate that group C rotavirus could infect not only older children and adults but also infants and young children under 3 years old. 相似文献
85.
Kawano Y Fukuda J Itoh H Takai N Nasu K Miyakawa I 《American journal of reproductive immunology (New York, N.Y. : 1989)》2004,52(2):124-128
PROBLEM: In order to investigate the role of macrophage colony-stimulating factor (M-CSF) and monocyte chemoattractant protein -1 (MCP-1) in human ovulation, we studied the regulation of M-CSF and MCP-1 in cultured human granulosa cells. METHOD OF STUDY: Immortalized granulosa cells (GC1a) were cultured in serum-free medium, and incubated with interleukin (IL)-1alpha, IL-1 receptor antagonist (ra) and tumor necrosis factor (TNF)-alpha. The supernatants were collected, and M-CSF and MCP-1 were measured by ELISA. RESULTS: The levels of M-CSF and MCP-1 were increased after treatment with IL-1alpha (1 nm) and TNF-alpha (1 nm) in a time-dependent manner. The levels of M-CSF and MCP-1 were significantly increased after treatment with IL-1alpha and TNF-alpha in a dose-dependent manner. However, the levels of M-CSF and MCP-1 were significantly decreased by treatment with IL-1alpha (1 nm) and/or increasing concentrations of IL-1 ra. CONCLUSIONS: Our data indicated that M-CSF and MCP-1 were regulated by IL-1alpha and TNF-alpha. It was suggested that M-CSF and MCP-1 may play an important role in human preovulatory processes. 相似文献
86.
Marchildon PA Sugiyama T Fukuda Y Peacock JS Asaka M Shimoyama T Graham DY Fukada Y 《Journal of clinical microbiology》2003,41(4):1480-1485
It has been suggested that enzyme immunoassay (EIA) kits validated in one region may yield variable diagnostic performance results in different regions, possibly due to strain-specific differences in antibody responses in different populations. We tested (13)C-urea breath test-characterized serum samples from 109 U.S. patients and 288 Japanese patients using enzyme immunoassay with different preparations of high-molecular-weight cell-associated (HM-CAP) antigens that are conserved across Helicobacter pylori strains. Replicate antigens were prepared from five H. pylori clinical isolates. Eight antigen preparations were evaluated: two of U.S. origin and six of Japanese origin. The accuracies achieved with the eight antigen preparations ranged from 94.4 to 96.3% with the U.S. samples. With the Japanese samples the accuracies achieved ranged from 92.3 to 97.2%. Use of a pool of HM-CAP antigens prepared from isolates from Japan resulted in a higher median enzyme immunoassay value and slightly fewer samples with indeterminate results compared to the results obtained by use of the U.S. standard HM-CAP antigen for H. pylori-positive patients (accuracies, 97.2 and 92.3%, respectively), suggesting that variations in performance between both antigen source and patient population might be reduced by using antigens pooled from several strains. 相似文献
87.
Active matrix metalloproteinases in the tear fluid of individuals with vernal keratoconjunctivitis 总被引:3,自引:0,他引:3
Kumagai N Yamamoto K Fukuda K Nakamura Y Fujitsu Y Nuno Y Nishida T 《The Journal of allergy and clinical immunology》2002,110(3):489-491
Corneal epithelial lesions distinguish vernal keratoconjunctivitis (VKC) from other ocular allergic diseases. Such lesions result from degradation of the corneal epithelial basement membrane, which comprises mostly type IV collagen and laminin. Matrix metalloproteinase 2 (MMP-2) and MMP-9 catalyze the degradation of these 2 extracellular matrix proteins. The possible role of MMP-2 and MMP-9 in the pathogenesis of corneal lesions associated with VKC was investigated by assaying tear fluid for the presence of these enzymes. Tear fluid was collected from 6 eyes of 6 patients with active VKC, 14 eyes of 14 patients with active allergic conjunctivitis, and 6 eyes of 6 nonallergic healthy volunteers. Gelatin zymography revealed that the tear fluid of healthy volunteers contained inactive proforms of both MMP-2 and MMP-9 but not the active forms of these enzymes. Active forms of MMP-2 or MMP-9 were detected in a minority of patients with allergic conjunctivitis. However, with the exception of one individual for whom active MMP-9 was not detected, tear fluid from all patients with VKC contained both proforms and active forms of MMP-2 and MMP-9. These results implicate MMP-2 and MMP-9 in the pathogenesis of corneal epithelial disorders associated with VKC. 相似文献
88.
Jun Nakayama Kiyohiko Angata Edgar Ong Tsutomu Katsuyama Minoru Fukuda 《Pathology international》1998,48(9):665-677
Polysialic acid is a developmentally regulated carbohydrate composed of a linear homopolymer of a-2,a-linked sialic acid residues. This unique glycan is mainly attached to the neural cell adhesion molecule (N-CAM) and implicated in many morphogenic events of the neural cells by modulating the adhesive property of N-CAM. Recently, the cDNA that encodes polysialyltransferase, which is responsible for the polysialylation of N-CAM, was successfully cloned from three mammalian species. This review focuses on the molecular cloning of human polysialyltransferase, designated PST. it then describes the number of enzymes actually required for the polysialylation of N-CAM using an in vitro polysialyltransferase assay. Comparisons between PST and another polysialyltransferase, sialyltransferase X (STX), are made and it Is demonstrated that both enzymes can independently form polysiatic acid In vitro , but that during neural development they coordinately but distinctly synthesize polysialic acid on N-CAM. The role of polysialic acid in the central nervous system is also discussed. Finally, evidence that the two polysialyltransferases, PST and STX, apparently have distinct roles in the development of neural cells is provided by using a neurite outgrowth assay. 相似文献
89.
Possible contribution of follicular interleukin-1beta to nitric oxide generation in human pre-ovulatory follicles 总被引:2,自引:0,他引:2
Tao M; Kodama H; Kagabu S; Fukuda J; Murata M; Shimizu Y; Hirano H; Tanaka T 《Human reproduction (Oxford, England)》1997,12(10):2220-2225
The aim of this study was to investigate the relationships between
follicular nitric oxide (NO) metabolite concentrations and several related
variables, with special reference to follicular interleukin- 1beta
(IL-1beta). The follicular fluid from the leading and secondary follicles
was collected individually from 20 women undergoing in-vitro fertilization
(IVF) treatment, and the concentrations of nitrite (NO2-) and nitrate
(NO3-) were determined fluorometrically using 2,3- diaminonaphthalene. Both
follicular nitrite (r = 0.42, P < 0.01) and nitrate (r = 0.49, P <
0.001) were found to be significantly correlated with follicular IL-1beta
concentrations. There were also significant positive correlations between
follicular nitrate and the number of oocytes retrieved (P < 0.01) and
serum oestradiol concentration on the day of human chorionic gonadotrophin
(HCG) administration (P < 0.05). When follicular cells were incubated in
vitro with 10 ng/ml of IL-1beta for 24 h, nitrate generation was
significantly (P < 0.01) elevated compared with the control. In
conclusion, our study demonstrates that follicular IL-1beta and the number
of developing follicles are significant variables that affect follicular NO
concentrations, and points to the possible contribution of IL-1beta to NO
generation in human preovulatory follicles.
相似文献
90.
Conserved tRNA gene cluster in starfish mitochondrial DNA 总被引:10,自引:0,他引:10
Howard T. Jacobs Shuichi Asakawa Takeyoshi Araki Kin-ichiro Miura Michael J. Smith Kimitsuna Watanabe 《Current genetics》1989,15(3):193-206
Summary Partial sequencing of mtDNA from four long-diverged species of starfish reveals the existence of a conserved cluster of 13 tRNA genes, organized in a manner similar to that of the tRNA cluster of sea urchin mtDNA, but located at a position distant from the presumed replication origin. These findings suggest that a clustered organization of tRNA genes may have been present in the ancestral mitochondrial genome, and raise the possibility that tRNAs may have catalyzed the dispersal rather than the accumulation of the genes which encode them. 相似文献