全文获取类型
收费全文 | 8167篇 |
免费 | 364篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 129篇 |
妇产科学 | 114篇 |
基础医学 | 1086篇 |
口腔科学 | 266篇 |
临床医学 | 546篇 |
内科学 | 2103篇 |
皮肤病学 | 85篇 |
神经病学 | 494篇 |
特种医学 | 238篇 |
外科学 | 1492篇 |
综合类 | 29篇 |
预防医学 | 213篇 |
眼科学 | 121篇 |
药学 | 568篇 |
中国医学 | 11篇 |
肿瘤学 | 1006篇 |
出版年
2023年 | 44篇 |
2022年 | 95篇 |
2021年 | 138篇 |
2020年 | 81篇 |
2019年 | 117篇 |
2018年 | 143篇 |
2017年 | 114篇 |
2016年 | 136篇 |
2015年 | 139篇 |
2014年 | 175篇 |
2013年 | 222篇 |
2012年 | 333篇 |
2011年 | 383篇 |
2010年 | 217篇 |
2009年 | 202篇 |
2008年 | 343篇 |
2007年 | 363篇 |
2006年 | 303篇 |
2005年 | 370篇 |
2004年 | 339篇 |
2003年 | 331篇 |
2002年 | 318篇 |
2001年 | 305篇 |
2000年 | 277篇 |
1999年 | 251篇 |
1998年 | 111篇 |
1997年 | 76篇 |
1996年 | 82篇 |
1995年 | 69篇 |
1994年 | 67篇 |
1993年 | 71篇 |
1992年 | 239篇 |
1991年 | 216篇 |
1990年 | 204篇 |
1989年 | 210篇 |
1988年 | 167篇 |
1987年 | 162篇 |
1986年 | 175篇 |
1985年 | 122篇 |
1984年 | 96篇 |
1983年 | 96篇 |
1982年 | 53篇 |
1979年 | 64篇 |
1978年 | 53篇 |
1977年 | 44篇 |
1975年 | 40篇 |
1974年 | 50篇 |
1973年 | 47篇 |
1972年 | 45篇 |
1971年 | 40篇 |
排序方式: 共有8574条查询结果,搜索用时 15 毫秒
41.
Tatsuo Yamazaki Shigeki Tomita Kazuhito Ichikawa Yuko Ono Fujiyuki Inaba Ichio Fukasawa Yasuo Imai Johji Imura Hirokazu Fukui Takahiro Fujimori Noriyuki Inaba 《Pathobiology》2006,73(4):176-182
OBJECTIVES: We investigated the relationship between P16-immunostaining patterns and clinicopathological factors in early uterine cervix cancers and assessed whether P16-immunostaining patterns predict the prognosis of the patients with early uterine cervix cancers. METHODS: Twenty-nine early squamous cell carcinoma (SCC) specimens of the uterus were examined using immunohistochemistry for P16 expression. The P16-immunostaining pattern was classified into two groups: the homogeneous type and the heterogeneous type. P16-immunostaining patterns were evaluated in different parts of the carcinoma in situ (CIS): the center of the tumor and the front interface of the infiltrating tumor. RESULTS: All specimens were of the homogeneous type in CIS. The P16-immunostaining pattern was significantly of the heterogeneous type in the front interface of the infiltrating tumor with lymphatic invasion, vascular invasion, lymph node metastasis, and recurrence. Regarding the P16-immunostaining patterns in the front interface of the infiltrating tumor, the patients with the heterogeneous type showed a significantly worse prognosis than the patients with the homogeneous type. CONCLUSIONS: The prognosis of patients with early uterine cervical SCC may be predicted by evaluating the P16-immunostaining pattern in the front interface of the infiltrating tumor. 相似文献
42.
Imai T Tanaka Y Okamoto T Yamamoto Y Horinouchi T Tanaka H Koike K Shigenobu K 《Acta physiologica Scandinavica》2002,176(1):57-63
Urinary bladder smooth muscle (UBSM) exhibits spontaneous contraction. This spontaneous mechanical activity is myogenic and can be closely related to the UBSM cell action potential to facilitate Ca2+ influx through voltage-gated Ca2+ channels. In the present study, to know whether this membrane electrical event is the exclusive mechanism to trigger spontaneous smooth muscle contraction, we compared the inhibitory effects of Ca2+ channel blockers on the spontaneous action potential and mechanical activity in the isolated guinea-pig UBSM. Both action potential and rhythmic contraction were generated spontaneously in the presence of atropine (1 microM), phentolamine (1 microM), propranolol (1 microM), suramin (10 microM) and tetrodotoxin (1 microM), which suggest that both phenomena were myogenic in origin. Nisoldipine (100 nM) and diltiazem (10 microM) completely eliminated the generation of action potential whereas its frequency was dramatically increased by a dihydropyridine Ca2+ agonist, BayK 8644 (1 microM). In contrast to disappearance of action potential in the presence of Ca2+ channel blockers, spontaneous contraction of UBSM was inhibited only partly by nisoldipine or diltiazem and most of the mechanical components persisted in these channel blockers. These results indicate that spontaneous action potential in UBSM cell is generated through the activation of L-type voltage-gated Ca2+ channels. The subsequent elevation of intracellular Ca2+ concentrations during a burst of action potentials can be partly responsible for the induction of UBSM mechanical activity. In addition, the present study provides evidence that UBSM spontaneous mechanical activity is also attributable to the mechanism(s) other than the generation of Ca2+ spike. 相似文献
43.
Watanabe M Shin'oka T Tohyama S Hibino N Konuma T Matsumura G Kosaka Y Ishida T Imai Y Yamakawa M Ikada Y Morita S 《Tissue engineering》2001,7(4):429-439
Tissue-engineered vascular autografts (TEVAs) were made by seeding 4-6 x 10(6) of mixed cells obtained from femoral veins of mongrel dogs onto tube-shaped biodegradable polymer scaffolds composed of a polyglycolid acid (PGA) nonwoven fabric sheet and a copolymer of L-lactide and caprolactone (n = 4). After 7 days, the inferior vena cavas (IVCs) of the same dogs were replaced with TEVAs. After 3, 4, 5, and 6 months, angiographies were performed, and the dogs were sacrificed. The implanted TEVAs were examined both grossly and immunohistologically. The implanted TEVAs showed no evidence of stenosis or dilatation. No thrombus was found inside the TEVAs, even without any anticoagulation therapy. Remnants of the polymer scaffolds were not observed in all specimens, and the overall gross appearance similar to that of native IVCs. Immunohistological staining revealed the presence of factor VIII positive nucleated cells at the luminal surface of the TEVAs. In addition, lesions were observed where alpha-smooth muscle actin and desmin positive cells existed. Implanted TEVAs contained a sufficient amount of extracellular matrix, and showed neither occlusion nor aneurysmal formation. In addition, endothelial cells were found to line the luminal surface of each TEVA. These results strongly suggest that "ideal" venous grafts with antithrombogenicity can be produced. 相似文献
44.
Mika Ogata Akinori Sukuya Chizuko Sugizaki Kaori Ikematsu Takanori Imai Hiroshi Tachimoto Motohiro Ebisawa 《Arerugī》2008,57(7):843-852
OBJECTIVE: We investigated the usefulness of skin prick test (SPT) for the diagnosis of egg white (EW) allergy in infants with atopic dermatitis who showed negative to EW CAPRAST, and followed up the EW-CAPRAST in this study. SUBJECTS AND METHODS: Data of negative SPT using Bifurcated needle (BN) were analyzed from the data of 202 atopic dermatitis infants, who had received SPT from January in 2001 to April in 2005. From the negative SPT value (average and standard deviation) positive SPT value was obtained. Among 202 cases, 89 suspected-egg allergy infants with negative IgE CAPRAST against EW at the time of first visit were recruited to examine the usefulness of SPT. Positive conversion of EW-CAPRAST was checked in 78 cases (65: egg allergy+, 13: egg allergy(-)) who had been followed up in our outpatient clinic. RESULTS: Range of negative SPT control value (mean+2SD) using BF among infants could be set as less than 2 mm for wheal and/or 5 mm for erythema. Among 89 suspected-egg allergy infants with negative EW-CAPRAST, 72 infants (80.9%) were diagnosed as egg allergy by the combination of elimination and provocation test, interestingly 39 infants (54.2%) showed positive SPT results. In the follow up study of 78 negative EW-CAPRAST cases, 47 EW-CAPRAST out of 65 egg-allergy cases turned positive later infantile period (mean EW-CAPRAST: 9.6+/-16.7 Ua/ml at 9.9+/-5.6 months old). EW-CAPRAST of 7 cases in 13 non-egg allergies also turned positive in the follow up, however EW-CAPRAST titer was relatively lower compared to that of egg allergies (1.1+/-1.5 Ua/ml at 13.3+/-2.6 months old). CONCLUSIONS: We experienced fairly number of atopic infants with negative EW-CAPRAST at the first outpatient visit, who were later diagnosed as egg allergy. In about half of these cases, SPT egg-allergy infants, three quarter of EW-CAPRAST turned positive around 10 months old. EW-CAPRAST of atopic infants without egg allergy also turned transiently and slightly positive. In the conclusions, SPT seemed to be more useful than EW-CAPRAST for the diagnosis of egg allergy in early infantile period, however provocation test should be required for the definitive diagnosis in suspected-egg allergy infants without any proof of egg-sensitization. 相似文献
45.
Hirose M Nishikawa A Shibutani M Imai T Shirai T 《Environmental and molecular mutagenesis》2002,39(2-3):271-278
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is one of the most prevalent carcinogenic heterocyclic amines in the environment, targeting the colon, prostate, pancreas, and mammary gland in rodents. Chemopreventive effects of synthetic and naturally occurring compounds on PhIP-induced rat mammary carcinogenesis were investigated in a series of experiments. In a PhIP feeding model, groups of 20-21 female F344 rats each, were treated with 0.02% PhIP alone or PhIP plus 0.5% 1-O-hexyl-2,3,5-trimethylhydroquinone (HTHQ), 1% green tea catechins, 1% alpha-tocopherol, 0.1% ellagic acid, or 1% chlorophyllin, each in the diet, or 0.1% caffeine in drinking water for 52 weeks. To assess the mechanism of HTHQ and caffeine inhibition of PhIP-induced carcinogenesis, effects of these compound on the in vitro metabolic activation of PhIP were examined in the presence of S9 mix. In the next series of experiments, the PhIP intragastric dose model was applied to allow separate investigation of the effects of chemicals during the initiation and postinitiation periods. In these experiments, female Sprague-Dawley rats were given eight intragastric doses of 100 mg/kg body weight during the first 4-8 weeks for initiation. Either during initiation or after initiation, or only after initiation, animals were treated with either corn or perilla oil at doses of 5 and 20%, conjugated fatty acid derived from safflower oil (CFA-S) or perilla oil (CFA-P) at a dose of 1%, arctiin at doses of 0.02 and 0.2% in the diet, or sodium nitrite (NaNO(2)) at a dose of 0.2% in drinking water. In the PhIP feeding model, administration of PhIP alone for 52 weeks induced adenocarcinomas in 40% of rats, but the incidence was remarkably reduced to 5% by the simultaneous treatment with 0.5% HTHQ, a strong lipophilic phenolic antioxidant, or to 10% by 0.1% caffeine. Administration of 1% chlorophyllin exerted similar, albeit weaker, effects. alpha-Tocopherol at a dose of 0.5% only reduced the multiplicity of carcinomas, and 1% green tea catechins only the mean size of mammary tumors. In a metabolic activation study of PhIP, HTHQ and caffeine clearly inhibited the formation of metabolites. In the PhIP gastric dose model, among the naturally occurring compounds examined, a plant lignan arctiin, perilla oil, which contains a large amount of n-6 alpha-linolenic acid, and CFA-S or CFA-P inhibited mammary tumor development, particularly in the postinitiation period, although a clear dose response was not observed. Treatment with 0.2% NaNO(2) in the initiation period was found to lower the volume of mammary tumors. The present results indicate that a number of compounds may be candidate chemopreventive agents against PhIP-induced mammary carcinogenesis, acting through different mechanisms and depending on the stage of carcinogenesis. 相似文献
46.
M Asano H Fukuzaki M Yoshida M Kumakura T Mashimo H Yuasa K Imai H Yamanaka 《Biomaterials》1989,10(8):569-573
Amorphous and crystalline copolymers with a relatively low molecular weight of 1800 were synthesized by direct copolycondensation of D-lactic acid and L-lactic acid in the absence of a catalyst, to evaluate their in vivo capabilities as biodegradable carriers for drug delivery systems. A luteinizing hormone-releasing hormone agonist, des-Gly10-(D-Leu6)-LH-RH ethylamide, was incorporated in a fine cylindrical copolymer formulation, under melt-pressing technique, a mild heat-pressure condition. This formulation was implanted subcutaneously in the back of male rats. The rate of in vivo degradation of amorphous copolymer was much faster than that of crystalline copolymer. Contrary to this tendency, the in vivo release of the drug from this amorphous formulation was held constant over a longer period, compared with the crystalline formulation. This can be closely related to the difference in dispersion of the drug in the formulation. 相似文献
47.
48.
Yasuyuki Tezuka Hiroshi Imai Tomoo Shiomi 《Macromolecular chemistry and physics.》1997,198(2):627-641
A series of mono- and bifunctional polystyrenes ( 1 c and 1 ′ c ) having 1-methylpyrrolidinium salt end groups were prepared through sequential derivatization, i.e., tosylation and quaternization reactions, of prepolymers having 3-hydroxypropyl groups ( 1 a and 1 ′ a ) produced by end-capping reactions of the relevant living polymers. The 1-methylpyrrolidinium salt end group was found to undergo a selective ring-opening reaction at 100°C by nucleophilic attack of a benzoate counter anion introduced by ion-exchange reaction. The ion-coupling reaction of 1 c and 1 ′ c with poly(styrene-co-acrylate salt) was found to take place upon coprecipitation of an equimolar mixture into methanol to afford ionically linked pseudo-graft and network products, respectively. The subsequent heat treatment, converting the ionic bond into a covalent one, results in branched and crosslinked polystyrene with predetermined structural parameters. 相似文献
49.
Itoh Y Igarashi T Tatsuma N Imai T Yoshida J Tsuchiya M Murakami M Fukunaga Y 《Autoimmunity》2000,32(3):193-197
We have previously reported that approximately 50% of children with chronic nonspecific complaints were positive for antinuclear antibodies (ANA), and that a novel autoantibody to a 62 kD protein (anti-Sa) was found in 40% of these ANA-positive patients. Therefore, we proposed a distinct disease entity termed autoimmune fatigue syndrome (AIFS). We hypothesized that if autoimmune mechanisms did play an important role in the pathogenesis of AIFS, it is possible that it is immunogenetically regulated as observed in other autoimmune disorders. In order to examine the immunogenetic background of AIFS patients, HLA-A, -B, -C, and -DR loci were analyzed serologically in 61 AIFS patients. AIFS was found to be positively associated with the class I antigen HLA-B61 and with the class II antigen HLA-DR9, with odds ratios of 2.77 (p = 0.015, Pcorr = 0.48) and 2.60 (p= 0.012, Pcorr = 0.17), respectively. A negative association was also found between AIFS and HLA-DR2 with odds ratio of 0.25 (p = 0.029, Pcorr = 0.041). When comparing anti-Sa positive AIFS patients with healthy controls, the odds ratios associated with HLA-B61, DR9, and DR2 were 3.42 (p = 0.021, Pcorr = 0.22), 3.96 (p = 0.0011, Pcorr = 0.015), and 0.16 (p = 0.0022, Porr = 0.031), respectively. Thus, the HLA associations observed in this study suggested that immunogenetic background might play a role in AIFS. 相似文献
50.
Eosinophil response in mast cell-deficient W/WV mice 总被引:1,自引:0,他引:1
Y Nawa M Owhashi J Imai T Abe 《International archives of allergy and applied immunology》1987,83(1):6-11
The combination of cyclophosphamide treatment and Toxocara canis infection is known as an effective way of causing a high level of eosinophilia in mice. When this treatment was applied to congenitally anemic, mast cell-deficient W/WV mice, eosinophil response was far less than that of their normal littermate +/+ mice. The degree of the defective eosinophil response in the peripheral blood of W/WV mice was severer than that in the bone marrow. The defective eosinophil response of W/WV mice was completely restored by bone marrow grafting 8 weeks prior to cyclophosphamide treatment and T. canis infection. The kinetics of the recovery of eosinophil response in the bone marrow of W/WV mice after bone marrow grafting was faster than that in the peripheral blood. Chemotactic reactivity of eosinophils obtained from bone marrow or peritoneal cavity of W/WV mice was essentially comparable to that of +/+ mice. These results suggest that, in addition to the production of eosinophils in the bone marrow, mast cell-derived factors play an important role in the mediation of peripheral blood eosinophilia. 相似文献