全文获取类型
收费全文 | 5244篇 |
免费 | 286篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 95篇 |
妇产科学 | 43篇 |
基础医学 | 710篇 |
口腔科学 | 105篇 |
临床医学 | 313篇 |
内科学 | 1496篇 |
皮肤病学 | 83篇 |
神经病学 | 534篇 |
特种医学 | 226篇 |
外科学 | 776篇 |
综合类 | 27篇 |
预防医学 | 121篇 |
眼科学 | 40篇 |
药学 | 400篇 |
中国医学 | 23篇 |
肿瘤学 | 519篇 |
出版年
2023年 | 27篇 |
2022年 | 64篇 |
2021年 | 139篇 |
2020年 | 93篇 |
2019年 | 123篇 |
2018年 | 142篇 |
2017年 | 94篇 |
2016年 | 102篇 |
2015年 | 112篇 |
2014年 | 165篇 |
2013年 | 190篇 |
2012年 | 326篇 |
2011年 | 328篇 |
2010年 | 216篇 |
2009年 | 169篇 |
2008年 | 267篇 |
2007年 | 299篇 |
2006年 | 293篇 |
2005年 | 277篇 |
2004年 | 229篇 |
2003年 | 264篇 |
2002年 | 235篇 |
2001年 | 91篇 |
2000年 | 121篇 |
1999年 | 104篇 |
1998年 | 46篇 |
1997年 | 49篇 |
1996年 | 30篇 |
1995年 | 35篇 |
1994年 | 39篇 |
1993年 | 31篇 |
1992年 | 100篇 |
1991年 | 64篇 |
1990年 | 76篇 |
1989年 | 69篇 |
1988年 | 59篇 |
1987年 | 67篇 |
1986年 | 62篇 |
1985年 | 46篇 |
1984年 | 34篇 |
1983年 | 34篇 |
1982年 | 30篇 |
1981年 | 23篇 |
1979年 | 19篇 |
1978年 | 13篇 |
1974年 | 13篇 |
1973年 | 19篇 |
1972年 | 12篇 |
1968年 | 15篇 |
1967年 | 13篇 |
排序方式: 共有5562条查询结果,搜索用时 15 毫秒
41.
Taro Okada Akira Yasoshima Koji Uetsuka Hiroyuki Nakayama Kunio Doi 《Experimental and toxicologic pathology》2003,55(2-3):147-152
Ultrastructual characteristics of the dorsal skin responses to a single irradiation of UVA (1100 kJ/m2) were examined in Wistar-derived hypotichotic WBN/ILA-Ht rats (HtRs). In the epidermis, mitochondrial swelling of some keratinocytes and dissociation of keratinocytes due to intercellular edema developed at 3 hours (h) after irradiation and continued to 48 h. At 6 h, in addition to these changes, necrosis of keratinocytes accompanied with infiltration of neutrophils was also observed in some portions, and epidermal hyperplasia with many keratinocytes showing nucleolar hypertrophy and some mitotic keratinocytes was observed at 48 h. In the dermis, mitochondrial swelling and/or partial cytoplasmic destruction in capillary endothelial cells and edema with inflammatory cell infiltration were observed at and after 3 h, and extravasation of erythrocytes was found in some capillaries at 48 h. Mitochondrial swelling was also frequently found in pericytes and fibroblasts. Inflammatory cells were mainly composed of neutrophils throughout the experimental period. Mild degranulation of mast cells which also showed mitochondrial swelling was observed at and after 3 h, and a close special relationship between mast cells and fibroblasts or neutrophils was sometimes observed. In conclusion, the most prominent change in the dorsal skin of HtRs exposed to UVA was degeneration of capillary endothelial cells, resulting in edema and inflammatory cell infiltration, and the most characteristic cytopathic effect of UVA was mitochondrial swelling, and it was common to keratinocytes, capillary endothelial cells, pericytes, mast cells, and fibroblasts. 相似文献
42.
Tateishi T Nakamura M Ueda M Himeno S Yamashita T Yamauchi T Nishi K Mori K Asonuma K Inomata Y Ando Y 《Rinsho byori. The Japanese journal of clinical pathology》2005,53(9):825-831
Recently nutrition support team (NST) has been established for the purpose of prevention of complications which are caused by nutrition disorders and reduction of the medical expenses. Although physical examinations and blood biochemical data had been used as the indexes evaluating nutritional of patients, they were not suitable for the evaluation for the short-term in-patient. On the contrary, serum albumin (ALB) has been wildly used as a nutritional marker. However, it is impossible to evaluate nutrition state for the short-term in-patient and acute phase disease patient accurately, because the plasma half-life is 21 days and it takes long time to detect the change in nutritional state by its value. Rapid turnover proteins (RTP), whose plasma half-life is shorter, has paid attention to evaluate nutritional state for the short-term in-patients and acute phase disease patients. Although, prognostic inflammatory and nutritional index (PINI) was considered as a useful maker for evaluating inflammatory and nutritional states using the concentrations of transthyretin (TTR), a RTP, alpha1-acid glycoprotein (alpha1-AG), a chronic inflammation marker, C reactive protein (CRP), a acute inflammation marker, and ALB, However, it has several pitfalls. We newly made serum amyloid A (SAA) index using SAA instead of CRP. When we compared SAA index with PINI in many diseases, it turned out that SAA index became a more effective index which reflected the patient condition than did PINI. As for this index, it is expected to be used by NST while further alternation may be needed. 相似文献
43.
We previously reported that ammonia induced apoptosis in cultured rat hippocampal neurons with moderate increases in the intracellular calcium concentration and decreases in phospho-BAD levels. Since this suggested the involvement of calcineurin in the apoptosis, the effects of calcineurin inhibitors, 1 microM cyclosporin A and 1 microM FK506, on the ammonia-induced neuronal apoptosis were tested. Both of the inhibitors abolished the neuronal apoptosis assessed by double staining with Hoechst 33258 and anti-neurofilament antibody, and the ammonia-induced decrease in phospho-BAD Ser(155) level. Thus, calcineurin appeared to be involved in the dephosphorylation of BAD at the sites including Ser(155) in ammonia-induced apoptosis. 相似文献
44.
The effects of an anxiolytic honokiol derivative, dihydrohonokiol-B (DHH-B) [3'-(2-propenyl)-5-propyl-(1,1'-biphenyl)-2,4'-diaol], on ammonia-induced increases in the intracellular Cl(-) concentration ([Cl(-)](i)) were examined using primary cultured rat hippocampal neurons. DHH-B (1-100 ng/ml), but not an inactive isomer of honokiol, magnolol (100 ng/ml), dose-dependently inhibited the ammonia-induced increases in [Cl(-)](i) without any changes in the control [Cl(-)](i). Such an effect of DHH-B was blocked by a gamma-aminobutylic acid A (GABA(A)) and GABA(C) Cl(-) channel blocker, 100 microM picrotoxin, and a GABA(C) receptor blocker, 10 microM (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid, but not by a GABA(A) receptor blocker, 10 microM bicuculline. Further, a GABA(C) receptor agonist, 200 microM cis-4-aminocrotonic acid, but not a GABA(A) receptor agonist, 10 microM muscimol, mimicked the effect of DHH-B. Thus, DHH-B appears to protect neurons from the ammonia-induced increases in [Cl(-)](i) through GABA(C) receptor stimulation. 相似文献
45.
46.
Nobuo Donkai Hiroshi Inagaki Kanji Kajiwara Hiroshi Urakawa Manfred Schmidt 《Macromolecular chemistry and physics.》1985,186(12):2623-2638
Imogolite, a natural product in the clay fraction of Japanese soil, was characterized through its dilute solution properties. Various methods were employed for this characterization, including viscosity, sedimentation, static/dynamic light scattering, and small angle X-ray scattering. All these measurements have revealed consistently that imogolite is represented by a rigid thin rod within the accuracy of available theories, where its repeat unit is composed of twelve gibbsite units. Since the evaluation of the chain length from the observed quantities depends on the molecular weight distribution, its effect was also considered where Mw/Mn ≈ 1,2 was estimated from the sedimentation profile. 相似文献
47.
Kenichi Wakasa Masami Sakurai Morito Monden Tsuyoshi Yamada Chikazumi Kuroda Taro Marukawa Jun Okamura 《Pathology international》1988,38(10):1363-1367
We describe a case of hepatocellular carcinoma in which a tumor embolus in the portal vein and 3 of 4 intrahepatic metastases were necrosed completely by Lipiodol transcatheter chemo-embolization (Lipiodol-TCE). Tumor emboli in the portal vein and intrahepatic metastases usually cannot be necrosed by conventional transcatheter chemo-embolization alone, because small nodules such as intrahepatic metastases and tumor emboli in the portal vein are supplied blood from the portal vein. However, in this case, Lipiodol-TCE was effective against tumor emboli in the portal vein and intrahepatic metastases. ACTA PATHOL JPN 38: 1363-1367, 1988. 相似文献
48.
Eimoto T Kitaoka M Ogawa H Niwa H Murase T Tateyama H Inagaki H Soji T Wang HJ 《Histopathology》2002,40(1):46-57
AIMS: Malignant thymic tumour histologically resembling a soft tissue sarcoma is extremely rare and defined as sarcomatoid carcinoma in the recent World Health Organization (WHO) classification. We report two such cases in which the tumour cells showed a prominent rhabdomyoblastic differentiation and analyse whether these tumours retain an epithelial nature at least in part. METHODS AND RESULTS: One tumour occurred in a 51-year-old man (Case 1) and the other in a 40-year-old woman (Case 2). Microscopically, both tumours consisted essentially of two types of tumour cells: spindle and large round cells, with no apparent epithelial components. Osteosarcomatous small foci were also found in Case 2. Immunohistochemically, desmin and muscle-specific actin were positive in the majority of both types of tumour cells, whereas myogenin was predominant in the spindle cells and myoglobin in the large round cells. Some of both types of cells expressed cytokeratin with co-expression of myoglobin in the large round cells, but with no myogenin in the spindle cells. Some cytokeratin-positive spindle cells were also negative for desmin. Ultrastructural examination of a recurrent tumour in Case 2 revealed some epithelial features among the spindle cells. Cytogenetic study of the same tumour showed a complex abnormality including der(16)t(1;16)(q12;q12.1), an identical pattern previously reported in a case of thymic squamous cell carcinoma. CONCLUSIONS: The findings support the definition in the WHO classification of sarcomatoid carcinoma that includes purely sarcomatous tumour as in the present cases. Occurrence of this type of tumour may indicate a relationship between thymic epithelial cells and myoid cells and/or a potential for divergent differentiation in thymic epithelial tumours. 相似文献
49.
Yoshio Iwakura Katsumi Hayashi Koichi Inagaki 《Macromolecular chemistry and physics.》1967,104(1):56-65
L - and DL-2-Alkyl-2-isocyanatoethyl chloroformates were synthesized by the phosgenation of the corresponding amino alcohols. These optically active or racemic difunctional compounds were submitted to polycondensation-addition with various diamines to form high molecular weight polyurethan-ureas having asymmetric carbon atoms along the main chain. The optically active polyurethan-ureas obtained had slightly higher melting points than the corresponding racemic polymers. 相似文献
50.
Kanji Kajiwara Nobuo Donkai Yuzuru Hiragi Hiroshi Inagaki 《Macromolecular chemistry and physics.》1986,187(12):2883-2893
The acidic aqueous solution of imogolite is proposed to be an ideal lyotropic system. No temperature dependence was marked on the two phase boundary concentrations (A and B points) of imogolite solutions as predicted by the theories of Flory and Onsager. A satisfactory quantitative agreement was observed with Onsager's theory. The polydispersity of rod lengths was found to shift the A point towards lower concentrations than expected from theory. 相似文献