全文获取类型
收费全文 | 6110篇 |
免费 | 283篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 85篇 |
妇产科学 | 58篇 |
基础医学 | 977篇 |
口腔科学 | 73篇 |
临床医学 | 393篇 |
内科学 | 1683篇 |
皮肤病学 | 17篇 |
神经病学 | 695篇 |
特种医学 | 195篇 |
外科学 | 860篇 |
综合类 | 28篇 |
预防医学 | 104篇 |
眼科学 | 98篇 |
药学 | 446篇 |
中国医学 | 21篇 |
肿瘤学 | 669篇 |
出版年
2023年 | 25篇 |
2022年 | 41篇 |
2021年 | 141篇 |
2020年 | 56篇 |
2019年 | 87篇 |
2018年 | 113篇 |
2017年 | 83篇 |
2016年 | 119篇 |
2015年 | 130篇 |
2014年 | 160篇 |
2013年 | 236篇 |
2012年 | 351篇 |
2011年 | 411篇 |
2010年 | 256篇 |
2009年 | 207篇 |
2008年 | 379篇 |
2007年 | 415篇 |
2006年 | 427篇 |
2005年 | 366篇 |
2004年 | 376篇 |
2003年 | 389篇 |
2002年 | 395篇 |
2001年 | 73篇 |
2000年 | 64篇 |
1999年 | 98篇 |
1998年 | 110篇 |
1997年 | 94篇 |
1996年 | 86篇 |
1995年 | 63篇 |
1994年 | 91篇 |
1993年 | 67篇 |
1992年 | 64篇 |
1991年 | 68篇 |
1990年 | 36篇 |
1989年 | 49篇 |
1988年 | 36篇 |
1987年 | 31篇 |
1986年 | 39篇 |
1985年 | 39篇 |
1984年 | 33篇 |
1983年 | 16篇 |
1982年 | 15篇 |
1981年 | 17篇 |
1980年 | 19篇 |
1979年 | 8篇 |
1978年 | 14篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 6篇 |
排序方式: 共有6442条查询结果,搜索用时 31 毫秒
51.
Hidekichi Takatoh Hisashi Iwamoto Mitsuru Ikezu Norio Katoh Seiki Ito Hiroshi Kaneko 《Pathology international》1987,37(5):737-746
Fourteen cases of gastrointestinal endocrine tumors were examined im-munohistochemically for peptide YY, pancreatic polypeptide, glucagon, and somatostatin. Peptide YY cells were present in seven tumors, pancreatic polypeptide cells in eight tumors, glucagon cells in six tumors, and somatostatin cells in nine tumors. All 7 rectal endocrine tumors examined were found to contain peptide YY, while in the tumors of the other sites peptide YY cells were not detected. Peptide YY cell population in the rectal tumors was small to moderate in comparison with pancreatic polypeptide and glucagon cell population. This study suggests that peptide YY cells may be a common constituent of rectal endocrine tumors together with pancreatic polypeptide and glucagon cells, and that the peptide YY spectrum of gastrointestinal endocrine tumors may be closely related to the location of the tumors. Moreover, it can also be said that peptide YY may be used as one of the markers of rectal endocrine tumors. 相似文献
52.
Norrie disease caused by a gene deletion allowing carrier detection and prenatal diagnosis 总被引:10,自引:0,他引:10
Albert de La Chapelle Eeva-Marja Sankila Mikael Lindlöf Pertti Aula Reuo Norio 《Clinical genetics》1985,28(4):317-320
Carrier determination and prenatal diagnosis in Norrie disease (ND) has so far not been reported. We describe a kindred with 4 members affected by ND in which a deletion comprising gene locus DXS7 on the short arm of the X chromosome defined by probe L1.28 causes the disorder. This allowed us to predict via chorion villus biopsy that a male foetus of a carrier woman is unaffected. 相似文献
53.
Atsuko Iwasa Yoshinao Oda Shuichi Kurihara Yoshihiro Ohishi Masafumi Yasunaga Izumi Nishimura Emi Takagi Hiroaki Kobayashi Norio Wake Masazumi Tsuneyoshi 《Pathology international》2008,58(12):757-764
Ovarian mature cystic teratomas (MCT) uncommonly undergo malignant transformation to squamous cell carcinoma (SCC). While alterations in the p53 tumor suppressor gene and protein have been shown, few studies have analyzed other molecular changes leading to this malignant conversion. The purpose of the present study was to investigate 21 samples of SCC arising in MCT for altered expression in known p53‐ and p16/Rb‐dependent cell cycle regulatory proteins, and the association between their expression and cellular proliferation and histological features. Overexpression of the p53 protein was observed in 14 SCC (67%), while four (19%) had point mutations in the p53 gene. Reduced expression of the p16 protein was observed in 18 SCC (86%), while p16 gene alterations (hypermethylation (29%) and point mutation (33%)) were found in 11 (52%). Furthermore, a statistically significant correlation was observed between p53 and Rb overexpression (P = 0.0010), and the overexpression of both p53 and Rb was respectively significantly correlated with increased cellular proliferation. The results indicate that alterations in both the p53 and p16‐Rb pathways are associated with SCC arising in MCT. 相似文献
54.
Nobuyuki Mochizuki Norio TakagiKoji Kurokawa Takayuki KawaiShintaro Besshoh Kouichi TanonakaSatoshi Takeo 《Neuroscience letters》2007
The N-methyl-D-aspartate (NMDA) receptor, a subtype of ionotropic glutamate receptors, plays an important role in the regulation of neuronal development, learning and memory, and neurodegenerative diseases. NMDA receptor blockade enhances neurogenesis in the hippocampal dentate gyrus in vivo. The effect of NMDA receptor antagonist on proliferation of neural progenitor cells, however, remains to be determined. We investigated changes in the diameter and number of neurospheres derived from the embryonic rat brain after NMDA receptor blockade. Cortical progenitor cells were isolated from gestational day 18 fetal rats according to the Percoll density gradient method. Cultured spheres expressed neural progenitor markers, musashi-1 and nestin. Immunohistochemical analysis demonstrated that cells in Dulbecco's modified Eagle medium/F12 containing 1% fetal bovine serum on day 8 differentiated to MAP-2-positive neurons and GFAP-positive astrocytes. The expression of NR1 and NR2B subunits of the NMDA receptor in neurospheres was detected. Neither brief nor sustained exposure to NMDA altered the diameter and number of neurospheres. Brief exposure to 30 μM MK-801, an NMDA receptor antagonist, decreased the diameter of neurospheres. Sustained exposure to 30 μM MK-801 decreased the diameter and number of neurospheres. Our results provide evidence that MK-801 directly decreased proliferation of neural progenitor cells. 相似文献
55.
Kiyonori Miura Hideaki Masuzaki Tadayuki Ishimaru Norio Niikawa Y. Jinno 《Journal of human genetics》1998,43(4):283-284
We found a HhaI/BstUI polymorphism in the 3′ untranslated region of a novel gene which was localized to 11p15.5. This region is one of prominent
imprinting domains and contains multiple imprinted genes, such as H19, IGF2 , KVLQT1, and p57
KIP2
, which suggests that regional factors might contribute to the imprinting.
This polymorphism will be useful in the allelic analysis of expression and methylation of the novel gene.
Received: July 24, 1998 / Accepted: July 29, 1998 相似文献
56.
Yoshino H Futakuchi M Cho YM Ogawa K Takeshita F Imai N Tamano S Shirai T 《Clinical & experimental metastasis》2005,22(5):441-447
Previously, we established the in vivo lung metastasis model of rat HCC induced by two hepatocarcinogens, diethylnitrosamine (DEN) and N-nitrosomorpholine (NMOR)
at a dose of 120 ppm. This model allows us to investigate modifying factors leading to the inhibition of metastasis formation.
However, low survival rates made the evaluation of metastasis formation difficult. The current experiments were conducted
to modify the experimental protocol to improve survival and to establish a better animal metastasis model. Lower doses of
NMOR (80 or 40 ppm in drinking water) were given to F344 rats for 14 weeks after DEN treatment. Survival rates in the 80 ppm
group and in the 40 ppm group were 57% and 81%, respectively and these values were significantly higher than that in 120 ppm.
Incidences of lung metastasis in the 40 ppm group steadily increased up to 67% by week 36 while that in the 80 ppm increased
sharply up to 86% by week 24. Severity of lung metastases in the 40 ppm group at week 36 was mild compared with the 80 ppm
group at week 24. In the second experiment, in order to characterize HCC development and lung metastasis in the 40 ppm group,
rats given DEN and then followed with 40 ppm NMOR were killed sequentially. Development of HCC was observed at week 14 and
reached 100% incidence at week 20. First lung metastatic lesions were evident at week 22, and incidence of lung metastasis
reached 100%. Tumor cells were identified in the blood at week 20 by RT-PCR. The current study revealed that 40 ppm NMOR for
14 weeks after DEN treatment developed HCC without lung metastases at week 22, then HCC with a frequent lung metastasis at
week 40. Thus, it can be said that this system is a more appropriate model for elucidation of mechanisms of metastasis and
also for analysis of factors to inhibit natural metastasis. 相似文献
57.
Masashi Ikeda Nakao Iwata Tatsuyo Suzuki Tsuyoshi Kitajima Yoshio Yamanouchi Yoko Kinoshita Norio Ozaki 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2005,(1):90-92
Several lines of evidence indicate that glycogen synthase kinase-3beta (GSK3beta) is one of the candidates for schizophrenia-susceptibility factor. However, it has not been reported the association analysis between GSK3beta gene (GSK3B) and Japanese schizophrenia based on linkage disequilibrium (LD). We provide an association analysis using relatively large samples (381 schizophrenia, and 352 controls) after determination of "tag single nucleotide polymorphisms (SNPs)." In this LD mapping, we selected and genotyped for eight polymorphisms (seven SNPs and one diallelic (CAA)(n) repeat), which covered the entire region of GSK3B, and determined two "tag SNPs." In the following association analysis using these two "tag SNPs," we could not find association with Japanese schizophrenia. Furthermore, we also include subgroup analysis considering age-at-onset and subtypes, neither could we find associations. Because our samples provided quite high power, these results indicate that GSK3B may not play a major role in Japanese schizophrenia. 相似文献
58.
A histological evaluation for guided bone regeneration induced by a collagenous membrane 总被引:5,自引:0,他引:5
Taguchi Y Amizuka N Nakadate M Ohnishi H Fujii N Oda K Nomura S Maeda T 《Biomaterials》2005,26(31):6158-6166
This study was designed to evaluate the histological changes during ossification and cellular events including osteogenic differentiation responding to collagenous bioresorbable membranes utilized for GBR. Standardized artificial bony defects were prepared at rat maxillae, and covered with a collagenous bioresorbable membrane. These animals were sacrificed at 1, 2, 3 and 4 weeks after the GBR-operation. The paraffin sections were subject to tartrate resistant acid phosphatase (TRAP) enzyme histochemistry and immunohistochemistry for alkaline phosphatase (ALP), osteopontin (OP) and osteocalcin (OC). In the first week of the experimental group, woven bone with ALP-positive osteoblasts occupied the lower half of the cavity. The collagenous membrane included numerous ALP-negative cells and OP-immunoreactive extracellular matrices. At 2 weeks, the ALP-, OP- and OC-immunoreactivity came to be recognizable in the region of collagenous membrane. Since ALP-negative soft tissue separated the collagenous membrane and the new bone originating from the cavity bottom, the collagenous membrane appeared to induce osteogenesis in situ. At 3 weeks, numerous collagen fibers of the membrane were embedded in the adjacent bone matrix. At 4 weeks, the membrane-associated and the cavity-derived bones had completely integrated, showing the same height of the periosteal ridge as the surrounding alveolar bones. The collagen fibers of a GBR-membrane appear to participate in osteogenic differentiation. 相似文献
59.
60.
Pseudotype hepatitis C virus enters immature myeloid dendritic cells through the interaction with lectin 总被引:3,自引:0,他引:3
Kaimori A Kanto T Kwang Limn C Komoda Y Oki C Inoue M Miyatake H Itose I Sakakibara M Yakushijin T Takehara T Matsuura Y Hayashi N 《Virology》2004,324(1):74-83
Dendritic cells (DC) are the most potent antigen-presenting cells that regulate immune responses. One of the mechanisms for hepatitis C virus (HCV) persistence is the ability of HCV to suppress DC function. Direct HCV infection to blood DC has been implicated for DC dysfunction. To clarify the susceptibility of each DC subset to HCV, we used pseudotype vesicular stomatitis virus (VSV) coated with chimeric HCV envelope glycoproteins (E1 and E2). We demonstrate that pseudotype VSV enters myeloid DC (MDC) but not plasmacytoid DC (PDC). The highest efficiency of pseudotype VSV entry to MDC was observed when MDC were cultured with GM-CSF. Such efficiency decreased when MDC are matured with the treatment of IL-4, CpG oligodeoxynucleotide, or CD40 ligand. Mannan inhibited pseudotype VSV entry to MDC, but Ca(2+) chelators failed to do so. These results show that pseudotype VSV possessing HCV-E1 and E2 enters immature MDC through the interaction with lectins in a Ca(2+)-independent manner. 相似文献