全文获取类型
收费全文 | 9103篇 |
免费 | 399篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 222篇 |
妇产科学 | 88篇 |
基础医学 | 1125篇 |
口腔科学 | 305篇 |
临床医学 | 544篇 |
内科学 | 2210篇 |
皮肤病学 | 147篇 |
神经病学 | 663篇 |
特种医学 | 459篇 |
外科学 | 1696篇 |
综合类 | 32篇 |
预防医学 | 165篇 |
眼科学 | 133篇 |
药学 | 479篇 |
中国医学 | 17篇 |
肿瘤学 | 1150篇 |
出版年
2023年 | 39篇 |
2022年 | 78篇 |
2021年 | 121篇 |
2020年 | 62篇 |
2019年 | 108篇 |
2018年 | 162篇 |
2017年 | 157篇 |
2016年 | 183篇 |
2015年 | 170篇 |
2014年 | 254篇 |
2013年 | 309篇 |
2012年 | 504篇 |
2011年 | 590篇 |
2010年 | 339篇 |
2009年 | 356篇 |
2008年 | 548篇 |
2007年 | 598篇 |
2006年 | 611篇 |
2005年 | 603篇 |
2004年 | 634篇 |
2003年 | 593篇 |
2002年 | 575篇 |
2001年 | 79篇 |
2000年 | 85篇 |
1999年 | 133篇 |
1998年 | 166篇 |
1997年 | 153篇 |
1996年 | 151篇 |
1995年 | 113篇 |
1994年 | 119篇 |
1993年 | 121篇 |
1992年 | 62篇 |
1991年 | 64篇 |
1990年 | 59篇 |
1989年 | 53篇 |
1988年 | 46篇 |
1987年 | 41篇 |
1986年 | 46篇 |
1985年 | 36篇 |
1984年 | 47篇 |
1983年 | 46篇 |
1982年 | 43篇 |
1981年 | 42篇 |
1980年 | 32篇 |
1979年 | 19篇 |
1978年 | 29篇 |
1977年 | 17篇 |
1976年 | 16篇 |
1974年 | 17篇 |
1973年 | 15篇 |
排序方式: 共有9542条查询结果,搜索用时 15 毫秒
991.
BACKGROUND/AIMS: The effectiveness of systematized hepatectomy in the modified International Union Against Cancer (UICC) staging classification for hepatocellular carcinoma (HCC) has not been clarified in detail. METHODS: We retrospectively studied 406 patients with UICC T1 HCC and 124 patients with T2 HCC who underwent initial curative hepatectomy from 1994 through 2003. Outcomes after sectionectomy or larger resection and segmentectomy or smaller resection for patients with T1 HCC and T2 HCC were examined. RESULTS: The overall recurrence-free survival rate and survival rate of sectionectomy or larger resection at 5 years (45 and 79%, respectively) did not significantly differ from those of segmentectomy or smaller resection (38 and 81%, respectively) in patients with T1 HCC. However, in patients with T2 HCC, the 5-year recurrence-free survival rate and survival rate after sectionectomy or larger resection (37 and 71%, respectively) were significantly different from those after segmentectomy or smaller resection (6%: p < 0.0001, and 35%: p = 0.0027, respectively). Multivariate analysis showed sectionectomy or larger resection to be a significant independent prognostic factor for recurrence-free survival and survival in patients with T2 HCC. CONCLUSIONS: Sectionectomy or larger resection prevents intrahepatic recurrence of HCC and prolongs survival in patients with T2 HCC. 相似文献
992.
Mechanisms of Tolerance Induced by Donor-Specific Transfusion and ICOS-B7h Blockade in a Model of CD4+ T-Cell-Mediated Allograft Rejection 总被引:1,自引:0,他引:1
Sigrid E. Sandner Michael R. Clarkson Alan D. Salama Alberto Sanchez-Fueyo Hideo Yagita Laurence A. Turka Mohamed H. Sayegh 《American journal of transplantation》2005,5(1):31-39
The inducible co-stimulatory molecule (ICOS) has been shown to play a critical role in T-cell activation and differentiation, and the regulation of alloimmune responses in vivo. Using an MHC class II mismatched model of CD4(+) T-cell-mediated rejection, we found that treatment of mice with DST and ICOS-B7h blockade induced long-term skin allograft survival and donor-specific transplantation tolerance. ICOS blockade, either during antigen priming or during the effector phase, previously shown to alter the outcome of the immune response, had a similar effect on graft survival. DST and anti-B7h mAb reduced the frequency of IFN-gamma-producing allospecific cells but did not produce deviation to a T(H)2 phenotype. In an adoptive transfer model using ABM TCR transgenic mice directly reactive to I-A(bm12), DST and anti-B7h mAb reduced the number of allospecific CD4(+) T cells and increased CD4(+) T-cell apoptosis. These data demonstrate that DST and anti-B7h mAb induces transplantation tolerance to MHC class II mismatched skin grafts by a reduction of the alloreactive clone size that is, at least in part, dependent on apoptosis of host alloantigen-specific CD4(+) T cells. 相似文献
993.
Akira T. Kawaguchi Munetaka Haida Hiroyuki Ohba Mariko Yamano Dai Fukumoto Hideo Tsukada 《Artificial organs》2013,37(10):904-912
Liposome‐encapsulated hemoglobin (LEH) is protective early after brain ischemia in rats and nonhuman primates, but it remains unclear whether the protection persists and confers any benefits beyond the acute phase of brain ischemia and reperfusion. Ten monkeys underwent middle cerebral artery occlusion, received LEH (2 mL/kg, n = 5) or saline (2 mL/kg, n = 5) 5 min later, and reperfusion 3 h later. Positron emission tomography studies were repeated for the cerebral metabolic rate of O2 (CMRO2) as well as glucose (CMRglc) up to 8 days after reperfusion, when the animals were euthanized for morphological studies. There was no difference in O2 metabolism until 3 h after reperfusion, when CMRO2 was significantly better preserved in the cortex, but not in basal ganglia, on Day 0 in LEH‐treated monkeys. The extent of cortical infarction (saline 68 ± 10% vs. LEH 38 ± 9%, P < 0.05) and CMRO2 (mild suppression: saline 34 ± 10% vs. LEH 14 ± 4%, P < 0.05) remained significantly better preserved 8 days later, when CMRglc showed a similar pattern of cortical protection (mild suppression: saline 49 ± 15% vs. LEH 37 ± 4%, P < 0.05) in LEH‐treated monkeys, together with regained body weight. Somatic weight control, morphological integrity, CMRO2, and CMRglc were better preserved immediately, as well as 8 days after occlusion and reperfusion of the middle cerebral artery in monkeys receiving LEH early after onset of ischemia. 相似文献
994.
Two-level posterior lumbar interbody fusion for degenerative disc disease: improved clinical outcome with restoration of lumbar lordosis 总被引:2,自引:0,他引:2
Akira Hioki MD Kei Miyamoto MD PhD Hirotaka Kodama MD PhD Hideo Hosoe MD PhD Hirofumi Nishimoto MD Hirofumi Sakaeda MD PhD Katsuji Shimizu MD DMSc 《The spine journal》2005,5(6):600-607
BACKGROUND CONTEXT: Although posterior lumbar interbody fusion (PLIF) for degenerative lumbar diseases is routine, there are few reports on double-level PLIF. PURPOSE: To evaluate the clinical outcomes of double-level PLIF. STUDY DESIGN/SETTING: A retrospective study of operated cases in Gifu, Japan. PATIENT SAMPLE: Nineteen patients (8 men and 11 women, 59.5+/-10.2 years) who underwent double-level PLIF between 1996 and 2001. OUTCOME MEASURES: Operation time, blood loss, complications, the Japanese Orthopaedic Association (JOA) score for back pain and lumbar sagittal alignment were evaluated. METHODS: Patients were examined retrospectively at follow-ups of 3.6+/-1.7 years. Primary diseases were spondylolisthesis, spinal canal stenosis, degenerative scoliosis and herniated intervertebral disc. Fusion areas were L3 to L5 in 15 cases and L4 to S1 in 4 cases. RESULTS: The mean JOA score increased from an initial score of 12.9+/-3.5 to 21.3+/-4.9 at the final follow-up. There was a positive correlation (R=0.718, p<.001) between the increase in lordotic angle and the increase in the JOA score. Several parameters suggested that the surgical invasiveness was not minimal. CONCLUSION: Double-level PLIF provided satisfactory results and preserved lumbar spine lordosis. 相似文献
995.
Fujimoto Sakata S Fujino M Matsuda K Maeda M Ohira H Kawasaki K Tamaki N 《Journal of nutritional science and vitaminology》2007,53(6):489-495
Liver tyrosine aminotransferase (TAT) activity is known to increase with ethanol treatment; however, the mechanism of this increase is unclear. Upon investigation we found that TAT activity and mRNA levels started to increase 2 h after ethanol administration and continued to increase until 6 h after ethanol administration. The increase in ethanol-induced TAT activity could not be explained by calorie loading after fasting, since ethanol loading increased TAT expression, while glucose loading decreased TAT expression. In addition, liver TAT activity was not related to serum tyrosine levels. TAT activity increased when an adenosine A2 agonist, 5'-N-ethylcarboxamide adenosine, was given. Since TAT activity is increased by cAMP, and ethanol increases cAMP production via an adenosine receptor-dependent mechanism, this increase in ethanol-induced TAT activity may occur via an adenosine receptor-dependent mechanism. 相似文献
996.
Kitamura J Kuroda S Ushikoshi S Furukawa K Asano T Shichinohe H Houkin K Iwasaki Y Saitoh H Mitsumori K 《No shinkei geka. Neurological surgery》2002,30(10):1097-1102
We report three cases of radiation-induced carotid arterial stenosis that underwent successful angioplasty with stenting. The patients had received radiation therapy for tongue or laryngeal cancers and developed minor completed strokes 6 to 14 years after irradiation. All patients had multiple and bilateral stenosis, measuring more than 50%, of the carotid arteries. The stenosis was located in the internal, external, and common carotid arteries. We performed percutaneous transluminal angioplasty with stenting. All interventions were successful and carotid stenosis decreased to less than 28%. No permanent complications occurred. During follow-up periods of up to 26 months, all of these cases were free from ischemic symptoms. Neither carotid angiography nor ultrasound sonography showed evidence of restenosis. The present results suggest the usefulness of angioplasty with stenting for radiation-induced carotid arterial stenosis. 相似文献
997.
Naomi Ohnuma Hideyo Takahashi Michio Kaneko Jun-Ichi Uchino Takeo Takeda Makoto Iwafuchi Mutsuro Ohhira Hirokazu Nishihira Hideo Mugishima Jotaro Yokoyama Akira Okada Noboru Nagahara Nobuyuki Taguchi Yoshiaki Tsuchida 《Pediatric blood & cancer》1995,24(3):181-187
One hundred and ten patients with advanced neuroblastoma were treated with the protocol of the Study Group of Japan between January 1985 and March 1991. Patients received six cyclic courses of regimen A1, consisting of cyclophosphamide (1,200 mg/m2), vincristine (1.5 mg/m2), tetrahydropyranyl adriamycin (40 mg/m2), and cisplatin (90 mg/m2). Primary tumors and regional lymph node metastases were removed some time during the first six cycles of regimen A1. After six cycles of A1, the patients were divided into three groups. Patients in group 1 received alternating treatment with regimen B (cyclophosphamide and ACNU) and intensified A1, and those in group 2 were treated with alternating administration of regimen C (cyclophosphamide and DTIC) and intensified A1. Patients in group 3 were treated with supralethal therapy and bone marrow transplantation (BMT). Event-free survival rates at five years were 38.8% in the chemotherapy group (groups 1 and 2) and 50.0% in the transplant group (group 3). Because of the study design that was not in truly randomized fashion and because of the small number of patients in each risk group, it is indicated, though not concluded, that the transplant group had a better prognosis than the chemotherapy group in the cases with stage III disease or with amplified N-myc oncogene, based on the statistical calculations. Differences in survival rates for patients who underwent BMT when complete remission (CR) was achieved and for those who achieved CR but who did not undergo marrow transplant were statistically insignificant. BMT-related death occurred in 3 of 31 cases (9.7%) undergoing marrow transplant, and the causes of the death included hemorrhagic pneumonia, myocardial disturbance and hemorrhagic uremia. © 1995 Wi1ey-Liss Inc. 相似文献
998.
999.
Stattaus J Maderwald S Baba HA Gerken G Barkhausen J Forsting M Ladd ME 《European radiology》2008,18(12):2865-2873
The purpose of this study was to evaluate the diagnostic efficacy of magnetic resonance (MR)-guided biopsy of focal liver
lesions within a short, wide-bore 1.5-T MR system and to determine the duration and accuracy of needle placement using MR
fluoroscopy guidance in 25 patients. Accuracy of needle placement was evaluated in two orthogonal planes, and the out-of-plane
angle of needle deflection was measured. Needle positioning was characterised subjectively as centred, peripheral, or exterior
relative to the lesion. Exterior positioning was corrected by a step-by-step procedure. Surgical resection (n = 6), previous histologies (n = 8), or clinical/radiological follow-up (n = 11) served as the ‘gold standard’. The guidance needle could be placed successfully using MR fluoroscopy in 20 of 25 patients
(80%). Needle placement was rated as ‘centred’ in 11 and as ‘peripheral’ in nine patients. Median needle deflection was 2.6
degrees, with a median deviation of 3.4 mm. In five patients, the direct approach failed or was rated as ‘exterior’; therefore,
repositioning after needle stabilisation with a stainless-steel stylet was necessary. The diagnostic yield of all biopsies
was: sensitivity 95.5%, specificity 100.0% and accuracy 96.0%. In conclusion, MR-guided biopsies in a short, wide-bore MR
system yielded highly reliable biopsy results, and in most cases the direct approach with MR fluoroscopy guidance proved to
be fast and accurate. 相似文献
1000.
Limitations of imaging diagnosis for small hepatocellular carcinoma: Comparison with histological findings 总被引:3,自引:0,他引:3
Hideo Horigome Tomoyuki Nomura Katsuhisa Saso Makoto Itoh Takashi Joh & Hirotaka Ohara 《Journal of gastroenterology and hepatology》1999,14(6):559-565
BACKGROUND AND AIMS: The purpose of this study was to clarify the value and limitation of imaging modalities for diagnosing small hepatocellular carcinoma (HCC). METHODS: Nodules (n = 207) with diameters of 20 mm or less detected by periodic ultrasonography and computed tomography in 139 patients with chronic liver disease were investigated with digital subtraction angiography (DSA) and magnetic resonance imaging (MRI). These findings were compared with histological findings. RESULTS: Histological diagnoses were adenomatous hyperplasia (AH, n = 27), well-differentiated HCC (n = 99), moderately differentiated HCC (n = 79) and poorly differentiated HCC (n = 2). We compared two groups: group A (n = 62), nodules of 10 mm diameters or less; and group B (n = 145), nodules 11-20 mm. Adenomatous hyperplasia accounted for approximately 30% of group A, but was difficult to diagnose with imaging modalities alone. We diagnosed those nodules showing hypervascular staining on DSA or hyperintensity on MRI T2-weighted images as HCC. Imaging alone was sufficient to diagnose HCC in 58% of the well-differentiated nodules and 87% of the moderately and poorly differentiated nodules (P < 0.01). It was possible to diagnose HCC by imaging alone in 60% of all nodules or 45% of group A and 68% of group B (A vs B, P < 0.005). CONCLUSIONS: With decreasing differentiation and increasing diameter of nodules, the use of imaging modalities to diagnose HCC improved. Tumour biopsy was required to diagnose 55% of the cases in group A and 32% of the cases in group B. 相似文献