全文获取类型
收费全文 | 26426篇 |
免费 | 1426篇 |
国内免费 | 143篇 |
专业分类
耳鼻咽喉 | 165篇 |
儿科学 | 657篇 |
妇产科学 | 400篇 |
基础医学 | 3300篇 |
口腔科学 | 692篇 |
临床医学 | 1735篇 |
内科学 | 6659篇 |
皮肤病学 | 497篇 |
神经病学 | 2338篇 |
特种医学 | 907篇 |
外科学 | 4171篇 |
综合类 | 145篇 |
一般理论 | 1篇 |
预防医学 | 793篇 |
眼科学 | 435篇 |
药学 | 1960篇 |
中国医学 | 31篇 |
肿瘤学 | 3109篇 |
出版年
2023年 | 150篇 |
2022年 | 302篇 |
2021年 | 506篇 |
2020年 | 277篇 |
2019年 | 350篇 |
2018年 | 508篇 |
2017年 | 367篇 |
2016年 | 438篇 |
2015年 | 504篇 |
2014年 | 614篇 |
2013年 | 759篇 |
2012年 | 1141篇 |
2011年 | 1280篇 |
2010年 | 743篇 |
2009年 | 620篇 |
2008年 | 1095篇 |
2007年 | 1263篇 |
2006年 | 1196篇 |
2005年 | 1234篇 |
2004年 | 1172篇 |
2003年 | 1107篇 |
2002年 | 1155篇 |
2001年 | 976篇 |
2000年 | 952篇 |
1999年 | 912篇 |
1998年 | 356篇 |
1997年 | 289篇 |
1996年 | 332篇 |
1995年 | 208篇 |
1994年 | 184篇 |
1993年 | 172篇 |
1992年 | 565篇 |
1991年 | 525篇 |
1990年 | 538篇 |
1989年 | 493篇 |
1988年 | 466篇 |
1987年 | 450篇 |
1986年 | 396篇 |
1985年 | 414篇 |
1984年 | 306篇 |
1983年 | 211篇 |
1982年 | 139篇 |
1979年 | 232篇 |
1978年 | 169篇 |
1977年 | 156篇 |
1974年 | 144篇 |
1971年 | 143篇 |
1970年 | 142篇 |
1968年 | 144篇 |
1967年 | 153篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Hideyuki Masuda Makoto Kimura Akiko Nishioka Hiroshi Kato Akimichi Morita 《Journal of dermatological science》2019,93(2):109-115
Background
Photosensitizers used for photodynamic therapy (PDT) to treat dermatologic disease are metabolized into mainly protoporphyrin IX (PpIX), which has five absorption wavelength peaks: 410?nm, 510?nm, 545?nm, 580?nm, and 630?nm. Although only red light around 635?nm and blue light around 400?nm are used as light sources for PDT, the efficiency of PDT might be improved by using multiple wavelengths, including those that correspond to the other absorption peaks of PpIX. Furthermore, because the target disease often occurs on the face, a flexible-type light-source unit that can be fitted to the lesion without unnecessarily exposing the mucous membranes, e.g., the eyes, nostrils, and mouth, is preferred.Objective
We investigated the efficacy of a flexible light-emitting diode (LED) unit that emits multiple wavelengths to improve PDT effects.Methods
HaCaT cells were incubated with 5-ALA and subsequently irradiated with either a single wavelength or sequentially with two wavelengths. Cell viability and reactive oxygen species were analyzed. Nude mice were implanted with COLO679 cells by subcutaneous injection into the flank. 5-ALA was subcutaneously injected into the tumor. The tumor was irradiated with 50?J/cm2 (day 0) and assessed daily until day 21.Results
The synergistic PDT effects of dual-wavelength irradiation and reactive oxygen species production were highest with the 405-nm and 505-nm wavelength combination. This dual wavelength combination was also the most effective in vivo.Conclusion
We could therefore conclude that dual-wavelength PDT is an efficient strategy for improving the therapeutic effects of PDT. Using a flexible LED unit is expected to achieve more uniform irradiation of uneven areas. 相似文献2.
3.
4.
5.
Taichi Goto Gojiro Nakagami Takeo Minematsu Sanai Tomida Masamichi Shinoda Koichi Iwata Hiromi Sanada 《Experimental dermatology》2019,28(9):1010-1016
Cutaneous wound pain causes physical and psychological stress for patients with wounds. Previous studies reported that stress induces hyperalgesia and deteriorates wound healing. However, the effect of the stress response such as in hypothalamic‐pituitary‐adrenal (HPA) axis on local wound area is unclear. We aimed to investigate the effects of a stress response on the mechanical withdrawal threshold in the local wound area and describe the identification of a wound pain exacerbation. We topically injected adrenocorticotropic hormone (ACTH) into the granulation tissue of full‐thickness cutaneous wound model rats on the fifth day postwounding and measured the mechanical withdrawal thresholds, cytochrome P450 2Bs levels and concentration of 5,6‐epoxyeicosatrienoic acid in wound exudate. We found that ACTH induced mechanical hypersensitivity at 4 and 6 hours after injection (P = .004 and .021, respectively), and increased gene expression of cytochrome P450 2B12 expression (P = .046). Concentration of 5,6‐EET in the wound exudate was moderately correlated with the mechanical withdrawal threshold (r = ?.630). Finally, the mechanical withdrawal threshold in the 5,6‐EET group was significantly lower than that in the control group at 2 hours after the injection (P = .015). We propose that 5,6‐EET is one of the most promising contributors to the wound pain exacerbation. These findings could guide clinical wound and pain management. 相似文献
6.
Kanji Takeo Eric Virtudazo Misako Ohkusu Susumu Kawamoto Shoko Ito-Kuwa Sigeji Aoki 《Nippon Ishinkin Gakkai Zasshi》2006,47(4):257-262
In Cryptococcus neoformans the DNA content of cells having tiny buds varied rather widely, depending on growth phases and strains used. Typically, buds of C. neoformans emerged soon after initiation of DNA synthesis in the early exponential phase. However, bud emergence was delayed to G2 during transition to the stationary phase, and in the early stationary phase budding scarcely occurred, although roughly half of the cells completed DNA synthesis. The timing of budding in C. neoformans was shifted to later cell cycle points with progression of the growth phase of the culture. Similarly, a deficit in oxygen was demonstrated to delay the timing of budding, prolong the G2 phase and cause accumulation of cells after DNA synthesis, but before commitment to budding. The C. neoformans homologue of the main cell cycle control gene CDC28/Cdc2 was isolated using degenerate RT-PCR. The full-length coding region was then amplified using primers to target the regions around the start and stop codons. The gene was called CnCdk1 and was found to have high homologies to S. cerevisiae CDC28 and S. pombe cdc2. To determine its function, its ability to rescue S. cerevisiae cdc28-temperature sensitive mutants was tested. S. cerevisiae cdc28-4 and cdc28-1N strains transformed with the pYES2-CnCdk1 construct exhibited growth at the restrictive temperature. Results of the sequence analysis and the ability of CnCdk1 to complement the S. cerevisiae cdc28-ts mutations support its assumed role as the CDC28/cdc2 homologue in C. neoformans. 相似文献
7.
Factors associated with levels of physical activity at work and during leisure time were analyzed among 577 subjects who had been selected as population controls for a case-control study by random selection from telephone directories. The intensity of physical activity at work was inversely associated with body mass index, the proportion of professionals & managers, consumption of western style breakfast, coffee, butter/margarine, and whisky; and positively associated with rice intake. Frequency of physical activities during leisure time was positively associated with consumption of vegetables, fruits, mushrooms, milk, cheese and coffee, and moderation in eating; and inversely associated with rice intake and the prevalence of gastrointestinal symptoms and medication. The association of physical activity with these factors should be considered in studying its relationship to disease risk. 相似文献
8.
Tanaka Takeo Kobayashi Masao Saito Osamu Kamada Nanao Kuramoto Atsushi Usui Tomofusa 《Clinica chimica acta; international journal of clinical chemistry》1981,117(2):121-131
The biochemical activities of 8 lysosomal acid hydrolases in leukemic cells from 48 patients were examined. Characteristic alterations were found in α-mannosidase, β-galactosidase and N-acetyl-β-glucosaminidase activities of leukemic cells. The level of α-mannosidase activity was much higher in myelo(mono)genous leukemias (AML, AMoL, AMMoL, CML and CMMoL) than in lymphogenous ones (ALL, T-cell leukemia, hairy cell leukemia and CLL) without exception. The β-galactosidase activity also differed as a result of α-mannosidase, except in T-cell leukemia. In T-cell leukemia it was within the range of normal lymphocytes, but in the other lymphogenous leukemias it was significantly below normal. N-acetyl-β-glucosaminidase activity in myelo(mono)genous leukemic cells was above the range of normal granulocytes. The changes in these enzyme levels were consistent. The lymphocytic or myelocytic nature of three cases of acute undifferentiated leukemia could be determined by enzyme studies. In two cases it was lymphocytic and in one it was myelocytic. The enzymatic abnormalities were also found in morphologically mature neutrophils from patients with not only chronic types (CML, CMMoL) but also acute types (AMoL, AMMoL) of leukemias, and were similar to those of their respective leukemic cells. Analysis of lysosomal enzymes (at least three of those mentioned above), can elucidate one of the biochemical properties of leukemic cells and may be valuable in the differentiation of leukemias. 相似文献
9.
Tadashi Kato 《Seishin shinkeigaku zasshi》2002,104(6):509-512
10.