全文获取类型
收费全文 | 2938篇 |
免费 | 156篇 |
专业分类
3094篇 |
出版年
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 32篇 |
2018年 | 33篇 |
2017年 | 29篇 |
2016年 | 50篇 |
2015年 | 68篇 |
2014年 | 70篇 |
2013年 | 261篇 |
2012年 | 182篇 |
2011年 | 183篇 |
2010年 | 101篇 |
2009年 | 123篇 |
2008年 | 161篇 |
2007年 | 170篇 |
2006年 | 163篇 |
2005年 | 163篇 |
2004年 | 172篇 |
2003年 | 165篇 |
2002年 | 160篇 |
2001年 | 46篇 |
2000年 | 42篇 |
1999年 | 40篇 |
1998年 | 36篇 |
1997年 | 39篇 |
1996年 | 31篇 |
1995年 | 35篇 |
1994年 | 38篇 |
1993年 | 29篇 |
1992年 | 39篇 |
1991年 | 24篇 |
1990年 | 28篇 |
1989年 | 23篇 |
1988年 | 27篇 |
1987年 | 23篇 |
1986年 | 11篇 |
1985年 | 20篇 |
1984年 | 28篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 27篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1974年 | 10篇 |
1973年 | 16篇 |
1972年 | 9篇 |
1970年 | 11篇 |
1966年 | 8篇 |
排序方式: 共有3094条查询结果,搜索用时 15 毫秒
121.
Minoru Niimoto Takao Hattori Ichiji Ito Ryuichiro Tamada Kiyoshi Inokuchi Kunzo Orita Hisashi Furue Nobuya Ogawa Tomohiro Toda Motonosuke Furusawa Shigemasa Koga Isamu Hashimoto Tatsuhei Kondo Shigeru Fujimoto Yuzuru Sugiyama Osahiko Abe Masaaki Oya 《Cancer immunology, immunotherapy : CII》1984,18(1):13-18
Summary The usefulness of LMS in postoperative immunochemotherapy of gastric cancer was investigated. In compliance with the protocol, MMC was given at a dose of 20 mg on the day of gastrectomy, and an additional 10 mg on the next day IV. The patients receiving 600 mg Tegafur daily were then divided into two groups according to whether LMS was also given or not. LMS was administered for 3 days before the operation in a daily dose of 150 mg and for 1 year or more after operation according to a schedule of 3 days' administration followed by an 11-day interval. The 2-year follow-up demonstrated that in stage III patients, the LMS (+) regimen was superior to the LMS (–) regimen, since the former prolonged the relapse-free interval significantly. The survival rate for stage III disease was also significantly higher in the LMS (+) than in the LMS (–) group. There was no significant difference in the incidence of subjective or objective side-effects between two groups. The incidence of agranulocytosis was comparable in the two groups.Gastrointestinal Cancer Research Group, Japan Levamisole Research AssociationChairmen of the Gastrointestinal Cancer Research Group, Japan LMS Research AssociationController of the Gastrointestinal Cancer Research Group, Japan LMS Research AssociationMembers of the Data Collection and Analysis SubcommitteeThis study was carried out by the Gastrointestinal Cancer Research Group, Japan LMS Research Association (directed by Prof. Kiyoshi Inokuchi, Dept. of Surgery, Kyushu University and Prof. Eiro Tsubura, Dept. of Internal Medicine, Tokushima University). The results were presented in part at the 19th General Meeting of the Japanese Society for Gastroenterological Surgery in February, 1982 相似文献
122.
Motokuni Nakazawa Minoru Yamada Ryuichi Uchikawa Naoki Arizono 《Cell and tissue research》1995,280(1):59-64
Various parasitic nematodes secrete acetylcholinesterase (AChE). In this study, the localization of AChE in the nematode Nippostrongylus brasiliensis and the secretory forms of AChE in culture fluid were examined. A thiocholine method revealed that AChE activity was localized in the subventral glands, which have a secretory and excretory function via a duct connected to the excretory pore. By electron microscopy, AChE activity was found mainly in the matrix of secretory granules, and sometimes in the Golgi apparatus in the subventral gland cells. These results show that nematode AChE is produced and stored in the subventral glands. Monoclonal antibodies against AChE of human erythrocytes or electric rays also bound to the nematode subventral gland, suggesting immuno-cross-reactivity of AChE among these species. When AChE activity in the nematode excretory-secretory product was examined by SDS polyacrylamide gel electrophoresis combined with the thiocholine method, intense activity was demonstrated as a single band at 74kDa. Immunoblot analysis showed specific recognition of this molecule by IgE and IgG1 antibodies, but not by IgG2a antibody, in nematode-infected rat sera. These results indicate that the nematode AChE molecule produced in and secreted from the subventral glands is antigenic for the production of IgE/IgG1 in host animals. 相似文献
123.
124.
125.
Bacillus stearothermophilus Neopullulanase Selective Hydrolysis of Amylose to Maltose in the Presence of Amylopectin 总被引:1,自引:0,他引:1 下载免费PDF全文
Hiroshi Kamasaka Kazuhisa Sugimoto Hiroki Takata Takahisa Nishimura Takashi Kuriki 《Applied microbiology》2002,68(4):1658-1664
The specificity of Bacillus stearothermophilus TRS40 neopullulanase toward amylose and amylopectin was analyzed. Although this neopullulanase completely hydrolyzed amylose to produce maltose as the main product, it scarcely hydrolyzed amylopectin. The molecular mass of amylopectin was decreased by only one order of magnitude, from approximately 108 to 107 Da. Furthermore, this neopullulanase selectively hydrolyzed amylose when starch was used as a substrate. This phenomenon, efficient hydrolysis of amylose but not amylopectin, was also observed with cyclomaltodextrinase from alkaliphilic Bacillus sp. strain A2-5a and maltogenic amylase from Bacillus licheniformis ATCC 27811. These three enzymes hydrolyzed cyclomaltodextrins and amylose much faster than pullulan. Other amylolytic enzymes, such as bacterial saccharifying α-amylase, bacterial liquefying α-amylase, β-amylase, and neopullulanase from Bacillus megaterium, did not exhibit this distinct substrate specificity at all, i.e., the preference of amylose to amylopectin. 相似文献
126.
Keisuke Maruyama Masaharu Nakamura Shusuke Tomoshige Kazuyuki Sugita Makoto Makishima Yuichi Hashimoto Minoru Ishikawa 《Bioorganic & medicinal chemistry letters》2013,23(14):4031-4036
Our multi-template approach for drug discovery, focusing on protein targets with similar fold structures, has yielded lead compounds for various targets. We have also shown that a diphenylmethane skeleton can serve as a surrogate for a steroid skeleton. Here, on the basis of those ideas, we hypothesized that the diphenylmethane derivative bisphenol A (BPA) would bind to the ligand-binding domain of estrogen receptors (ERs) in a similar manner to estradiol and act as a steroid surrogate. To test this idea, we synthesized a series of BPA analogs and evaluated their structure-activity relationships, focusing on agonistic/antagonistic activities at ERs and ERα/ERβ subtype selectivity. Among the compounds examined, 18 was found to be a potent ERα-antagonist with high selectivity over ERβ and androgen receptor under our assay conditions. A computational docking study suggested that 18 would bind to the antagonistic conformation of ERα. ERα-selective antagonists, such as 18, are candidate agents for treatment of breast cancer. 相似文献
127.
Miyagi Y Higashiyama M Gochi A Akaike M Ishikawa T Miura T Saruki N Bando E Kimura H Imamura F Moriyama M Ikeda I Chiba A Oshita F Imaizumi A Yamamoto H Miyano H Horimoto K Tochikubo O Mitsushima T Yamakado M Okamoto N 《PloS one》2011,6(9):e24143
Background
Recently, rapid advances have been made in metabolomics-based, easy-to-use early cancer detection methods using blood samples. Among metabolites, profiling of plasma free amino acids (PFAAs) is a promising approach because PFAAs link all organ systems and have important roles in metabolism. Furthermore, PFAA profiles are known to be influenced by specific diseases, including cancers. Therefore, the purpose of the present study was to determine the characteristics of the PFAA profiles in cancer patients and the possibility of using this information for early detection.Methods and Findings
Plasma samples were collected from approximately 200 patients from multiple institutes, each diagnosed with one of the following five types of cancer: lung, gastric, colorectal, breast, or prostate cancer. Patients were compared to gender- and age- matched controls also used in this study. The PFAA levels were measured using high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)–mass spectrometry (MS). Univariate analysis revealed significant differences in the PFAA profiles between the controls and the patients with any of the five types of cancer listed above, even those with asymptomatic early-stage disease. Furthermore, multivariate analysis clearly discriminated the cancer patients from the controls in terms of the area under the receiver-operator characteristics curve (AUC of ROC >0.75 for each cancer), regardless of cancer stage. Because this study was designed as case-control study, further investigations, including model construction and validation using cohorts with larger sample sizes, are necessary to determine the usefulness of PFAA profiling.Conclusions
These findings suggest that PFAA profiling has great potential for improving cancer screening and diagnosis and understanding disease pathogenesis. PFAA profiles can also be used to determine various disease diagnoses from a single blood sample, which involves a relatively simple plasma assay and imposes a lower physical burden on subjects when compared to existing screening methods. 相似文献128.
Minoru Ishii Shunpei Uemoto Kunimitsu Fujieda Mizuo Nonaka Yukihiro Shoyama Yumi Miyahara Itsuo Nishioka 《Phytochemistry》1979,18(7):1211-1213
A new phenolic, hydroxyeucomic acid, and dopamine were isolated from Cattleya trianaei and their biological activities examined. 相似文献
129.
Claudia Azucena Palafox Sánchez Minoru Satoh Edward KL Chan Wendy C Carcamo José Francisco Muñoz Valle Gerardo Orozco Barocio Edith Oregon Romero Rosa Elena Navarro Hernández Mario Salazar Páramo Antonio Cabral Castañeda Mónica Vázquez del Mercado 《Arthritis research & therapy》2009,11(1):1-12
Introduction
In rheumatoid arthritis (RA), synovial fluid (SF) contains a large number of neutrophils that contribute to the inflammation and destruction of the joints. The SF also contains granulocyte-macrophage colony-stimulating factor (GM-CSF), which sustains viability of neutrophils and activates their functions. Using proteomic surveillance, we here tried to elucidate the effects of GM-CSF on neutrophils.Methods
Neutrophils stimulated by GM-CSF were divided into four subcellular fractions: cytosol, membrane/organelle, nuclei, and cytoskeleton. Then, proteins were extracted from each fraction and digested by trypsin. The produced peptides were detected using matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry (MALDI-TOF MS).Results
We detected 33 peptide peaks whose expression was upregulated by more than 2.5-fold in GM-CSF stimulated neutrophils and identified 11 proteins out of the 33 peptides using MALDI-TOF/TOF MS analysis and protein database searches. One of the identified proteins was neutrophil gelatinase-associated lipocalin (NGAL). We confirmed that the level of NGAL in SF was significantly higher in patients with RA than in those with osteoarthritis. We next addressed possible roles of the increased NGAL in RA. We analysed proteome alteration of synoviocytes from patients with RA by treatment with NGAL in vitro. We found that, out of the detected protein spots (approximately 3,600 protein spots), the intensity of 21 protein spots increased by more than 1.5-fold and the intensity of 10 protein spots decreased by less than 1 to 1.5-fold as a result of the NGAL treatment. Among the 21 increased protein spots, we identified 9 proteins including transitional endoplasmic reticulum ATPase (TERA), cathepsin D, and transglutaminase 2 (TG2), which increased to 4.8-fold, 1.5-fold and 1.6-fold, respectively. Two-dimensional electrophoresis followed by western blot analysis confirmed the upregulation of TERA by the NGAL treatment and, moreover, the western blot analysis showed that the NGAL treatment changed the protein spots caused by post-translational modification of TERA. Furthermore, NGAL cancelled out the proliferative effects of fibroblast growth factor (FGF)-2 and epidermal growth factor (EGF) on chondrocytes from a patient with RA and proliferative effect of FGF-2 on chondrosarcoma cells.Conclusions
Our results indicate that GM-CSF contributes to the pathogenesis of RA through upregulation of NGAL in neutrophils, followed by induction of TERA, cathepsin D and TG2 in synoviocytes. NGAL and the upregulated enzymes may therefore play an important role in RA. 相似文献130.