全文获取类型
收费全文 | 13300篇 |
免费 | 872篇 |
国内免费 | 266篇 |
专业分类
耳鼻咽喉 | 115篇 |
儿科学 | 233篇 |
妇产科学 | 191篇 |
基础医学 | 1692篇 |
口腔科学 | 438篇 |
临床医学 | 1060篇 |
内科学 | 3129篇 |
皮肤病学 | 141篇 |
神经病学 | 723篇 |
特种医学 | 536篇 |
外国民族医学 | 1篇 |
外科学 | 2097篇 |
综合类 | 544篇 |
现状与发展 | 2篇 |
预防医学 | 732篇 |
眼科学 | 189篇 |
药学 | 1032篇 |
1篇 | |
中国医学 | 213篇 |
肿瘤学 | 1369篇 |
出版年
2023年 | 85篇 |
2022年 | 224篇 |
2021年 | 298篇 |
2020年 | 214篇 |
2019年 | 250篇 |
2018年 | 290篇 |
2017年 | 249篇 |
2016年 | 285篇 |
2015年 | 302篇 |
2014年 | 430篇 |
2013年 | 478篇 |
2012年 | 740篇 |
2011年 | 796篇 |
2010年 | 460篇 |
2009年 | 420篇 |
2008年 | 650篇 |
2007年 | 678篇 |
2006年 | 562篇 |
2005年 | 619篇 |
2004年 | 529篇 |
2003年 | 513篇 |
2002年 | 495篇 |
2001年 | 411篇 |
2000年 | 375篇 |
1999年 | 342篇 |
1998年 | 154篇 |
1997年 | 108篇 |
1996年 | 114篇 |
1995年 | 97篇 |
1994年 | 96篇 |
1993年 | 97篇 |
1992年 | 294篇 |
1991年 | 260篇 |
1990年 | 247篇 |
1989年 | 263篇 |
1988年 | 212篇 |
1987年 | 217篇 |
1986年 | 222篇 |
1985年 | 174篇 |
1984年 | 130篇 |
1983年 | 123篇 |
1982年 | 73篇 |
1979年 | 95篇 |
1978年 | 77篇 |
1977年 | 60篇 |
1975年 | 54篇 |
1974年 | 69篇 |
1973年 | 51篇 |
1972年 | 56篇 |
1971年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Shengxuan Cao Chen Wang Xin Ma Xu Wang Jiazhang Huang Chao Zhang Li Chen Xiang Geng Kan Wang 《Journal of orthopaedic research》2019,37(8):1860-1867
Patients with mechanic ankle instability experience increased tibiotalar and subtalar joint laxity. However, in vivo joint kinematics in functional ankle instability (FAI) patients and lateral ankle sprain (LAS) copers, especially during dynamic activities, are poorly understood. Ten FAI patients, 10 LAS copers, and 10 healthy controls were included in this study. A dual fluoroscopic imaging system was used to analyze the tibiotalar and subtalar joint kinematics during stair descent. Five key poses of stair descent were analyzed. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint positions in each degree of freedom were compared among the three groups. The tibiotalar joints of FAI patients and LAS copers were significantly more inverted than those of healthy controls during the foot strike (p = 0.016, = 0.264). The subtalar joints of FAI patients were significantly more anteriorly translated (pose 2, p = 0.003, = 0.352; pose 3, p < 0.001, = 0.454; pose 4, p = 0.004, = 0.334), inverted (pose 4, p = 0.027, = 0.234; pose 5,p = 0.034, = 0.221), and externally rotated (pose 4, p = 0.037, = 0.217; pose 5; p = 0.004, = 0.331) than those of healthy controls during the mid‐stance and the heel off. The FAI patients showed excessive tibiotalar inversion and subtalar joint hypermobility during stair descent. Meanwhile, the LAS copers maintained subtalar joint stability, and only showed excessive tibiotalar inversion in foot strike. These data provide insight into the mechanisms behind the development of FAI after initial LAS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1860–1867, 2019 相似文献
2.
Regional fractional ventilation mapping in spontaneously breathing mice using hyperpolarized 129Xe MRI
下载免费PDF全文
![点击此处可从《NMR in biomedicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hirohiko Imai Hironobu Matsumoto Erika Miyakoshi Shintaro Okumura Hideaki Fujiwara Atsuomi Kimura 《NMR in biomedicine》2015,28(1):24-29
The feasibility of ventilation imaging with hyperpolarized (HP) 129Xe MRI has been investigated for quantitative and regional assessment of ventilation in spontaneously breathing mice. The multiple breath ventilation imaging technique was modified to the protocol of spontaneous inhalation of HP 129Xe delivered continuously from a 129Xe polarizer. A series of 129Xe ventilation images was obtained by varying the number of breaths before the 129Xe lung imaging. The fractional ventilation, r, was successfully evaluated for spontaneously breathing mice. An attempt was made to detect ventilation dysfunction in the emphysematous mouse lung induced by intratracheal administration of porcine pancreatic elastase (PPE). As a result, the distribution of fractional ventilation could be visualized by the r map. Significant dysfunction of ventilation was quantitatively identified in the PPE‐treated group. The whole‐lung r value of 0.34 ± 0.01 for control mice (N = 4) was significantly reduced, to 0.25 ± 0.07, in PPE‐treated mice (N = 4) (p = 0.038). This study is the first application of multiple breath ventilation imaging to spontaneously breathing mice, and shows that this methodology is sensitive to differences in the pulmonary ventilation. This methodology is expected to improve simplicity as well as noninvasiveness when assessing regional ventilation in small rodents. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
3.
Eitaro Ito Akihiro Takai Yoshinori Imai Hiromi Otani Yoshihiro Onishi Yosuke Yamamoto Kohei Ogawa Taiji Tohyama Shunichi Fukuhara Yasutsugu Takada 《Surgery》2019,165(2):353-359
Background
Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.Methods
This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.Results
A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.Conclusion
Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy. 相似文献4.
5.
Shigeko Tanaka Minoru Yoshiyama Yukihiro Imanishi Koichi Nakahira Takashi Hanaki Yukari Naito Mizue Imai Masahiro Tanaka 《Magnetic resonance in medical sciences》2006,5(4):207-210
One diagnostic criterion for metabolic syndrome is obesity from the accumulation of visceral fat; others include abdominal circumference and area of visceral fat as measured by computed tomography (CT) at the umbilical level. We evaluated visceral fat using frequency-selective excitation magnetic resonance (MR) imaging SPAIR (spectral attenuation with inversion recovery) water suppression THRIVE (3D T1-high resolution isotropic volume examination). Fifty of 70 slices with 2-mm interval were used to render and measure volume of visceral fat ranging within 10 cm of the umbilicus; the area of visceral fat at the umbilical level was also measured. Imaging was completed using breath hold within 14 s. Image processing was easier than using CT. 相似文献
6.
Yoshifumi Kan 《中华心血管病杂志》2003,31(Z1):62
Many institutions in Japan perform PCI via the radial artery(TRI), due to the adility of TRI to improve the quality of life of patients. However, this procedure involves the significant problem of causing narrowing of the radial artery or occlusion by trans-radial approach. 相似文献
7.
Lifetime fracture risk: an approach to hip fracture risk assessment based on bone mineral density and age 总被引:8,自引:0,他引:8
Hip fractures occur late in life following a substantial reduction in skeletal mass. If risk for such fractures could be predicted early, efforts to prevent excessive bone loss would be more successful and could be directed at the individuals most likely to be affected. With this objective in mind, we devised an approach to estimating the lifetime risk of a proximal femur fracture based on age and on current femoral bone mineral density, using population-based data from ongoing studies of osteoporosis and fractures among Rochester, Minnesota, women. Our calculations indicate that, at any given age, the lifetime risk of a proximal femur fracture rises as current bone density diminishes. At any given level of femoral bone density, lifetime risk rises with younger age and increasing life expectancy. While these trends seem robust, estimates of risk vary substantially with the assumptions that underlie the model. Consequently, these assumptions must be validated before our findings can be applied clinically to predict risk for individual patients. 相似文献
8.
S Kawata S Noda Y Imai S Tamura R Saitoh S Miyoshi Y Minami S Tarui 《Gastroenterologia Japonica》1987,22(1):55-62
The pharmacokinetics of 1-(tetrahydro-2-furanyl)-5-fluorouracil (FT) and its conversion into 5-fluorouracil (FUra) in liver tissue were studied in ten patients with hepatocellular carcinoma (HCC). The plasma concentration of FT after its intravenous injection (dosage: 800 mg) was computerfitted to a bi-exponential function (C = Ae-alpha t + Be-beta t), indicating a two-compartment disposition. The pharmacokinetic parameters did not significantly differ between the five patients with, and the five without cirrhosis of the liver. The plasma concentrations of FUra likewise showed no significant difference between the two groups. The rates of FT degradation in the liver tissue homogenate were similar for four of the patients with cirrhosis (0.10 +/- 0.05 mumol/g liver protein/30 min) and four of those without it (0.13 +/- 0.05). The rates of cytochrome P-450-dependent FUra formation in the microsomal fraction of liver tissue from two patients (1.1 and 1.3 nmol/mg microsomal protein/30 min) were dramatically reduced to less than half of those of two control subjects (2.4 and 2.7). The estimated rates of FUra formation in the soluble fraction (105,000 X g supernatant fraction) from the two patients (0.1 and 0.13 nmol/mg protein/30 min) were almost identical to those from the controls (0.12 and 0.14), suggesting that the rate in the soluble fraction from HCC patients may not be as strongly affected as the rate in the microsomal fraction.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
Immunohistochemical and immunoelectron microscopical characterization of cerebrovascular and senile plaque amyloid in aged dogs'' brains 总被引:2,自引:0,他引:2
Tokuhiro Ishihara Toshikazu Gondo Mutsuo Takahashi Fumiya Uchino Shu-Ichi Ikeda David Allsop Kohzoh Imai 《Brain research》1991,548(1-2):196-205
Immunohistochemical and immunoelectron microscopical studies were carried out on 28 aged dogs' brains. Amyloid deposits were seen in the arteries and capillaries in the leptomeninges and in superficial areas of the cortices in 19 (67.9%) of the 28 dogs (10-22 years of age). Immunohistochemically, these amyloid deposits were reactive for anti-beta/A4 antibody. Additionally, a variable number of parenchymal deposits with diffuse beta/A4-immunoreactivity (diffuse plaques) was also noted throughout the cerebral cortex in 24/28 dogs (85.7%). However, these plaque lesions were undetectable in Congo red staining. Electron microscopically, amyloid fibrils, measuring 10 nm in width, were located mainly in the tunica media of the arteries, and in less involved vessels they tended to be present among collagen fibres in the adventitia and smooth muscle cells in the outer layer of the media. The plaque lesions appeared to contain sparse aggregations of amyloid fibrils. In immunoelectron microscopical examinations, all amyloid fibrils in both blood vessels and plaques were selectively labelled by gold particles. These findings indicate that aged dogs can provide a useful experimental model for research into the beta/A4-type of cerebral amyloidosis commonly seen in Alzheimer's disease. 相似文献
10.
S Mizuno H Funahashi H Sugiura T Imai M Takeuchi Y Sato H Takagi 《Nihon Geka Gakkai zasshi》1986,87(8):883-888
Bilateral cervical lymph node dissection was performed in 71 cases of papillary thyroid carcinoma, considered to be relatively early cases because of mobility, irrespective of the size of tumor or presence of node enlargement. Of these, 33 cases received additional node dissection of the anterosuperior mediastinum through longitudinal sternotomy. The number of lymph nodes examined per subject averaged 89.9, the number of metastatic nodes was 13.8, and metastasis was noted in 88.7% of all cases. Lymph node metastasis tended to be more frequent on the affected side, but was simultaneously scattered over the whole cervical area. As to sites, metastasis of paratracheal nodes on the affected side occurred at a frequency of 66.2%, inferior and superior jugular nodes at 62.0% and 59.0% respectively, pretracheal nodes at 50.7%, and tracheoesophageal nodes at 47.9%. The high incidence of para- and pretracheal nodes suggests that the lymph flow in this direction is of great importance in metastasis. In fact, lymph nodes in the mediastinum, which were directly continuous with these nodes, showed as high as 39.4% metastasis in cases of anterosuperior mediastinal extirpation. This extensive node dissection is considered to be very preferable as at least the agony of survival with carcinoma can be lessened. 相似文献