全文获取类型
收费全文 | 8854篇 |
免费 | 462篇 |
国内免费 | 64篇 |
专业分类
耳鼻咽喉 | 162篇 |
儿科学 | 261篇 |
妇产科学 | 105篇 |
基础医学 | 1025篇 |
口腔科学 | 177篇 |
临床医学 | 512篇 |
内科学 | 2530篇 |
皮肤病学 | 142篇 |
神经病学 | 585篇 |
特种医学 | 458篇 |
外科学 | 1566篇 |
综合类 | 31篇 |
一般理论 | 1篇 |
预防医学 | 176篇 |
眼科学 | 134篇 |
药学 | 482篇 |
中国医学 | 13篇 |
肿瘤学 | 1020篇 |
出版年
2023年 | 67篇 |
2022年 | 66篇 |
2021年 | 288篇 |
2020年 | 127篇 |
2019年 | 200篇 |
2018年 | 252篇 |
2017年 | 207篇 |
2016年 | 224篇 |
2015年 | 225篇 |
2014年 | 288篇 |
2013年 | 366篇 |
2012年 | 606篇 |
2011年 | 632篇 |
2010年 | 326篇 |
2009年 | 260篇 |
2008年 | 501篇 |
2007年 | 540篇 |
2006年 | 534篇 |
2005年 | 566篇 |
2004年 | 462篇 |
2003年 | 508篇 |
2002年 | 487篇 |
2001年 | 111篇 |
2000年 | 118篇 |
1999年 | 136篇 |
1998年 | 114篇 |
1997年 | 86篇 |
1996年 | 74篇 |
1995年 | 85篇 |
1994年 | 61篇 |
1993年 | 66篇 |
1992年 | 103篇 |
1991年 | 68篇 |
1990年 | 57篇 |
1989年 | 57篇 |
1988年 | 43篇 |
1987年 | 58篇 |
1986年 | 41篇 |
1985年 | 34篇 |
1984年 | 24篇 |
1983年 | 28篇 |
1982年 | 14篇 |
1981年 | 21篇 |
1980年 | 24篇 |
1979年 | 42篇 |
1978年 | 20篇 |
1977年 | 16篇 |
1970年 | 14篇 |
1969年 | 16篇 |
1968年 | 17篇 |
排序方式: 共有9380条查询结果,搜索用时 15 毫秒
11.
Keisuke Mitsuoka Sosuke Miyoshi Yukio Kato Yoshihiro Murakami Rie Utsumi Yoshiyuki Kubo Akihiro Noda Yukio Nakamura Shintaro Nishimura Akira Tsuji 《Journal of nuclear medicine》2008,49(4):615-622
H+/peptide transporter, PEPT1, is functionally expressed in some human cancer cell lines and might be a candidate molecular target for detection of cancers in vivo using PET. The aim of the present study was to establish a novel tumor-imaging technology using a PET tracer targeted to H+/peptide transporter(s). We also compared the tracer with 18F-FDG, focusing on the specificity of their accumulation between tumor and inflammatory tissues. METHODS: A dipeptide PET tracer, 11C-glycylsarcosine (11C-Gly-Sar), was injected intravenously into athymic mice transplanted with human pancreatic, prostate, and gastric cancer cells. The distribution patterns of 11C-Gly-Sar and 18F-FDG in the tumor-bearing mice, and in mice with inflammatory tissue, were assessed by imaging with a positron planar imaging system (PPIS). Tissue distributions of tracer radioactivity were also measured. The expression levels of PEPT1 and PEPT2 (PEPTs) proteins in tumor xenografts and inflammatory tissue were examined by immunohistochemical analysis. The messenger RNA expression levels of PEPTs in 58 available cancer cell lines were quantified by means of real-time polymerase chain reaction. RESULTS: All 3 tumor xenografts were well visualized with the PPIS after injection of 11C-Gly-Sar. Expression of PEPTs in those xenografts was confirmed by immunohistochemical analysis. Tumor-to-blood concentration ratios of 11C-Gly-Sar increased in a time-dependent manner and were much higher than unity. Most of the radioactivity found in the tumor tissue was recovered as the intact tracer. These results indicated that 11C-Gly-Sar was taken up by the PEPTs in tumor xenografts. It is noteworthy that 11C-Gly-Sar was minimally present in inflammatory tissues that expressed no PEPT1 or PEPT2 protein, whereas 18F-FDG was highly accumulated, with the values of the selectivity index being >25.1 and 0.72 for 11C-Gly-Sar and 18F-FDG, respectively. The mRNAs of PEPT1 and PEPT2 were expressed in 27.6% and 93.1%, respectively, of the cancer cell lines examined in the present study. CONCLUSION: The present study indicates that 11C-Gly-Sar is a promising tumor-imaging agent and is superior to 18F-FDG for distinguishing between tumors and inflammatory tissue. Because PEPTs were ubiquitously expressed in various types of tumor cells examined, 11C-Gly-Sar could be useful for the detection of many types of cancers. 相似文献
12.
Daisuke Kubota Takanori Kanai Fumiro Yui Tomoko Matsumoto Takahiro Kawamura Yasuhiro Itsui Eriko Okada Seishin Chin Shinya Ooka Masakazu Nagahori Kiichiro Tsuchiya Akihiro Araki Naoya Sakamoto Tatsuya Miyata Mamoru Watanabe 《Nihon Shokakibyo Gakkai zasshi》2007,104(1):42-46
A 44-year-old women developed marked myopathy one year earlier, when she was treated with intravenous prednisolone for acute severe exacerbation of ulcerative colitis. When she was admitted to our hospital for another severe exacerbation, intravenous cyclosporine A was administered as monotherapy because she could not tolerate corticosteroid. The treatment was successful and she obtained complete remission. Cyclosporine A monotherapy is considered to be a valuable alternative to proctocolectomy for severe ulcerative colitis patients who cannot tolerate corticosteroid. 相似文献
13.
14.
15.
Seiichi Saito Shunichi Namiki Kenji Numahata Makoto Satoh Shigeto Ishidoya Akihiro Ito Haruo Nakagawa Yasuhiro Kaiho Takehiko Sanada Atsushi Yamada Yoichi Arai 《International journal of urology》2007,14(2):133-139
PURPOSE: To determine the effect of an interposition nerve graft on sexual function after radical prostatectomy. METHODS: This study includes 64 patients, without hormonal therapy, who underwent a radical prostatectomy and intraoperative electrophysiological confirmation of cavernous nerve preservation. Twelve patients underwent a unilateral interposition sural nerve graft (UNG) for the resected neurovascular bundle. Twenty-one and 31 patients underwent bilateral nerve-sparing (BNS) and unilateral nerve-sparing (UNS) surgery without a nerve graft, respectively. As the age of patients was significantly younger in the UNG group than in the other groups, age-matched analysis also was conducted. Sexual function, evaluated by a self-administered questionnaire using the University of California Los Angeles-Prostate Cancer Index, was compared statistically among the three groups. RESULTS: In the age-matched analysis, the postoperative sexual function (SXF) score of the UNG group showed an intermediate level of recovery between those of the BNS and UNS groups at 12 months and reached the same level as the score at 12 months of the BNS group at 18 months postoperatively. The difference in the SXF score between the UNG and UNS groups began to appear after 6 months postoperatively and increased steadily with time. However, the background factors, such as the baseline SXF score, the usage rate of phosphodiesterase 5 inhibitors, and the rate of comorbidities were different between the UNG and UNS groups. CONCLUSIONS: The difference of the SXF score between the UNG and UNS groups increased with time after 6 months postoperatively. However, it might be difficult at present to attribute a better recovery of the SXF score to the nerve graft because of the difference in the background factors between the groups. 相似文献
16.
Abstract: A prospective study was performed to determine whether low-density lipoprotein (LDL) apheresis, when performed only immediately before and after percutaneous transluminal coronary angioplasty (PTCA), is effective in preventing restenosis of coronary artery lesions following PTCA. Thirty-six patients with coronary heart disease (CHD) and hypercholesterolemia were divided into 2 groups. The 9 patients in the LDL group underwent LDL-apheresis 1 day before and 5 days after PTCA while the 27 patients of the control group underwent PTCA but did not undergo LDL-apheresis. Follow-up coronary angiography (CAG) was performed 4 months after PTCA. The rate of restenosis of coronary artery lesions was significantly lower in the LDL group (0%) than in the control group (30%). These findings suggest that LDL-apheresis, when performed before and after PTCA, is effective in preventing restenosis of coronary artery lesions in patients with CHD and hypercholesterolemia. 相似文献
17.
K. Arima Minako Nakamura Nobuhiko Sunohara Masafumi Ogawa Midori Anno Yoko Izumiyama Shigeo Hirai Kazuhiko Ikeda 《Acta neuropathologica》1997,93(6):558-566
Coiled bodies and interfascicular threads are conspicuous white matter abnormalities of brains of patients with progressive
supranuclear palsy (PSP). Both structures are argyrophilic and immunoreactive for the microtubule-binding protein tau. This
report concerns the ultrastructural localization of interfascicular threads and their relationship to coiled bodies in five
PSP patients. We showed for the first time that abnormal tubules with a 13- to 15-nm diameter and fuzzy outer contours were
the common structures of coiled bodies in the oligodendroglial perikarya and of interfascicular threads. Moreover, the tubules
were immunolabeled by anti-tau antibodies. The abnormal tau-positive tubules of interfascicular threads were located in the
inner loop of the myelin sheath. Our study further indicated that the thread-like structures in the white matter comprised,
at least in part, oligodendroglial processes, and that they were also present in gray matter. We consider that the formation
of coiled bodies in the perikarya and of interfascicular threads represents a common cytoskeletal abnormality of the oligodendroglia
of PSP patients. Moreover, even though the white matter alterations of PSP resemble those of corticobasal degeneration, there
are certain ultrastructural differences in the abnormal oligodendroglial tubules of the two diseases.
Received: 4 October 1996 / Accepted: 6 December 1996 相似文献
18.
Imura Akihiro; Hori Toshiyuki; Imada Kazunori; Kawamata Shin; Tanaka Yuetsu; Imamura Sadao; Uchiyama Takashi 《Blood》1997,89(8):2951-2958
19.
20.
Shoji Fukushima Akihiro Hagiwara Masao Hirose Shuji Yamaguchi Danai Tiwawech Nobuyuki Ito 《Cancer science》1991,82(6):642-649
Modifying potentials of various chemicals on tumor development were investigated in a wide-spectrum organ carcinogenesis model using male F344/DuCrj rats. The animals were treated with N-nitroso-diethylamine (100 mg/kg body weight, ip, single injection at the commencement of the study), N-methyl-N-nitrosourea (20 mg/kg body weight, ip, 4 times during weeks 1 and 2) and N-bis(2-hydroxypropyl)nitrosamine (0.1% in drinking water, during weeks 3 and 4) for multi-organ initiation and then were given one of 14 test chemicals including 6 hepatocarcinogens, 7 non-hepatocarcinogens and 1 non-carcinogen, or basal diet for 16 weeks. All rats were killed at the end of week 20, and the major organs were carefully examined for preneoplastic and neoplastic lesions. Immunohistochemical demonstration of glutathione S -transferase-positivc foci was also used for quantitative assessment of liver preneoplastic lesion development. Modifying effects were shown for 11 out of 14 test agents in the liver, forestomach, glandular stomach, lung, urinary bladder or thyroid, 7 of them targeting more than two organs. This was the first demonstration to our knowledge that cloflbrate possesses enhancing potential for urinary bladder carcinogenesis and an inhibiting effect on thyroid carcinogenesis. Caprolactam showed no effect in any organ, in agreement with its established inactivity. The results indicated that the system could be reliably applied as a medium-term multiple organ bioassay for assessment of the modification potential of test agents in unknown target sites. 相似文献