全文获取类型
收费全文 | 4679篇 |
免费 | 156篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 86篇 |
妇产科学 | 69篇 |
基础医学 | 610篇 |
口腔科学 | 72篇 |
临床医学 | 265篇 |
内科学 | 1165篇 |
皮肤病学 | 54篇 |
神经病学 | 361篇 |
特种医学 | 202篇 |
外科学 | 900篇 |
综合类 | 34篇 |
预防医学 | 101篇 |
眼科学 | 185篇 |
药学 | 239篇 |
中国医学 | 8篇 |
肿瘤学 | 497篇 |
出版年
2023年 | 19篇 |
2022年 | 48篇 |
2021年 | 96篇 |
2020年 | 46篇 |
2019年 | 68篇 |
2018年 | 76篇 |
2017年 | 65篇 |
2016年 | 98篇 |
2015年 | 103篇 |
2014年 | 139篇 |
2013年 | 182篇 |
2012年 | 291篇 |
2011年 | 305篇 |
2010年 | 144篇 |
2009年 | 136篇 |
2008年 | 267篇 |
2007年 | 297篇 |
2006年 | 261篇 |
2005年 | 292篇 |
2004年 | 293篇 |
2003年 | 286篇 |
2002年 | 296篇 |
2001年 | 56篇 |
2000年 | 65篇 |
1999年 | 95篇 |
1998年 | 64篇 |
1997年 | 68篇 |
1996年 | 59篇 |
1995年 | 61篇 |
1994年 | 57篇 |
1993年 | 62篇 |
1992年 | 43篇 |
1991年 | 42篇 |
1990年 | 29篇 |
1989年 | 33篇 |
1988年 | 24篇 |
1987年 | 24篇 |
1986年 | 25篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1983年 | 26篇 |
1982年 | 19篇 |
1981年 | 20篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 17篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1974年 | 13篇 |
1971年 | 8篇 |
排序方式: 共有4871条查询结果,搜索用时 0 毫秒
91.
92.
93.
Yoshihiro Wakayama Satoshi Hirako Tetsuo Ogawa Takahiro Jimi Seiji Shioda 《ACTA HISTOCHEMICA ET CYTOCHEMICA》2014,47(1):27-33
Aquaporin (AQP) is suggested to be regulated by leptin through the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin pathway. AQP7 and AQP9 are membrane proteins with water and glycerol channels, the latter of which is essential for triglyceride synthesis. We conjectured that the expression of AQP7 and AQP9 would be altered in the skeletal myofibers in obese leptin deficient ob/ob mice as compared with that of wild mice. RNA and protein levels were studied in the quadriceps femoris muscles of ob/ob and wild mice. Real time quantitative RT-PCR analysis showed that mouse AQP7 mRNA levels in skeletal muscles were significantly higher in ob/ob mice than in wild mice (P<0.01), whereas mouse AQP9 mRNA level was not different between the two groups (P>0.05). Histologically the type 1 myofibers of ob/ob mice contained numerous lipid droplets in oil red O stain samples. Immunohistochemical staining of ob/ob mouse muscles revealed enhanced expression of AQP7 at myofiber surface membranes, while AQP9 expression appeared to be similar to that of wild mice. The findings suggest that the upregulated expression of AQP7 in ob/ob mouse muscles facilitates the secretion of glycerol from myocytes. 相似文献
94.
95.
96.
97.
Tatsuhiko Kuroda Shiro Tanaka Mitsuru Saito Yumiko Shiraki Masataka Shiraki 《Calcified tissue international》2013,93(3):269-275
The aim of this cross-sectional cohort study was to clarify risk factors for severe vertebral fractures in postmenopausal Japanese women. Subjects were ambulatory volunteers age over 50 years who were recruited from a population of outpatients at a primary care institute. At registration, age, body mass index (BMI), bone mineral density (BMD), and present illness were investigated. Biochemical parameters including urinary levels of type I collagen cross-linked N-telopeptides (NTXs), and pentosidine and plasma levels of homocysteine were measured. Values were compared with different fracture grades (grade 0–3). A total of 1,475 postmenopausal women (66.6 ± 9.0 years) were included in the present study. Distributions of vertebral fracture grades were grade 1, 137 cases (9.3 %); grade 2, 124 cases (8.4 %); and grade 3, 162 cases (11.0 %). Age, BMI, BMD, NTX, pentosidine, and homocysteine were significantly associated with vertebral fracture in unadjusted analysis. In addition, a higher prevalence of hypertension was observed in patients with severe fracture. When comparing vertebral fracture grade 0 versus grade 2–3 by multiple regression analysis, pentosidine and homocysteine levels were a significant risk for moderate/severe vertebral fracture (odds ratio [OR] = 1.17, 95 % confidence interval [CI] 1.00–1.38, p = 0.049; OR = 1.22, 95 % CI 1.03–1.46, p = 0.013). Homocysteine levels were also a significant risk when comparing vertebral fracture grade 0 versus grade 3 (OR = 1.27, 95 % CI 1.04–1.58, p = 0.021). Plasma level of homocysteine was an independent risk for severe vertebral fractures. 相似文献
98.
Ryuta Shigefuku Hideaki Takahashi Minoru Kobayashi Hiroki Ikeda Kotaro Matsunaga Chiaki Okuse Nobuyuki Matsumoto Shiro Maeyama Shigeru Sase Michihiro Suzuki Fumio Itoh 《Journal of gastroenterology》2012,47(11):1238-1247
Introduction
Effective noninvasive tests that can distinguish early-stage nonalcoholic steatohepatitis (NASH) from simple steatosis (SS) have long been sought. Our aim was to determine the possibility of noninvasively distinguishing early-stage NASH from SS.Materials and methods
We used Fick’s principle and the Kety–Schmidt equation to determine the hepatic tissue blood flow (TBF) in 65 NASH patients who underwent xenon computed tomography (Xe-CT). We calculated the lambda value (LV), i.e., Xe gas solubility coefficient, in liver and blood. We assessed the histological severity of fatty changes and fibrosis on the basis of Brunt’s classification. Liver biopsy revealed SS in 9 patients and NASH in 56 patients. NASH stages 1 and 2 were classified as early-stage NASH (Ea-NASH; 38 patients) and stages 3 and 4 as advanced-stage NASH (Ad-NASH; 18 patients). We evaluated the differences in LV and TBF among the 3 groups.Results
LV was significantly lower in the Ad-NASH group than in the SS and Ea-NASH groups. Portal venous TBF (PVTBF) was significantly lower in the Ea-NASH group than in the SS group, and PVTBF was lower in the Ad-NASH group than in the Ea-NASH group. Total hepatic TBF (THTBF) was significantly different between the SS and Ea-NASH groups and between the SS and Ad-NASH groups.Conclusions
In conclusion, measurements of TBF and LV are useful for evaluating the pathophysiological progression of NASH. In addition, these measurements can facilitate the differential diagnosis of SS and Ea-NASH, which may not be distinguishable by other means. 相似文献99.
Terasaki M Tanaka S Oka S Nakadoi K Takata S Kanao H Yoshida S Chayama K 《Journal of gastroenterology and hepatology》2012,27(4):734-740
Background and Aims: Colorectal laterally spreading tumors (LST) > 20 mm are usually treated by endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR). Endoscopic piecemeal mucosal resection (EPMR) is sometimes required. The aim of our study was to compare the outcomes of ESD and EMR, including EPMR, for such LST. Methods: A total of 269 consecutive patients with a colorectal LST > 20 mm were treated endoscopically at our hospital from April 2006 to December 2009. We retrospectively evaluated the complications and local recurrence rates associated with ESD, hybrid ESD (ESD with EMR), EMR, and EPMR. Results: ESD and EMR were performed successfully for 89 and 178 LST, respectively: 61 by ESD; 28 by hybrid ESD; 70 by EMR; and 108 by EPMR. Between‐group differences in perforation rates were not significant. Local recurrence rates in cases with curative resection were as follows: 0% (0/56) in ESD; 0% (0/27) in hybrid ESD; 1.4% (1/69) in EMR; and 12.1% (13/107) in EPMR; that is, significantly higher in EPMR. No metastasis was seen at follow up. The recurrence rate for EPMR yielding ≥ three pieces was significantly high (P < 0.001). All 14 local recurrent lesions were adenomas that were cured endoscopically. Conclusions: As for safety, ESD/hybrid ESD is equivalent to EMR/EPMR. ESD/hybrid ESD is a feasible technique for en bloc resection and showed no local recurrence. Although local recurrences associated with EMR/EPMR were seen, which were conducted based on our indication criteria, all local recurrences could obtain complete cure by additional endoscopic treatment. 相似文献
100.