全文获取类型
收费全文 | 7726篇 |
免费 | 384篇 |
国内免费 | 77篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 221篇 |
妇产科学 | 96篇 |
基础医学 | 918篇 |
口腔科学 | 228篇 |
临床医学 | 454篇 |
内科学 | 1792篇 |
皮肤病学 | 126篇 |
神经病学 | 588篇 |
特种医学 | 414篇 |
外科学 | 1697篇 |
综合类 | 23篇 |
预防医学 | 138篇 |
眼科学 | 65篇 |
药学 | 430篇 |
中国医学 | 9篇 |
肿瘤学 | 910篇 |
出版年
2023年 | 49篇 |
2022年 | 91篇 |
2021年 | 139篇 |
2020年 | 102篇 |
2019年 | 124篇 |
2018年 | 169篇 |
2017年 | 132篇 |
2016年 | 164篇 |
2015年 | 185篇 |
2014年 | 238篇 |
2013年 | 293篇 |
2012年 | 455篇 |
2011年 | 473篇 |
2010年 | 243篇 |
2009年 | 198篇 |
2008年 | 429篇 |
2007年 | 479篇 |
2006年 | 468篇 |
2005年 | 473篇 |
2004年 | 417篇 |
2003年 | 395篇 |
2002年 | 414篇 |
2001年 | 160篇 |
2000年 | 163篇 |
1999年 | 176篇 |
1998年 | 101篇 |
1997年 | 73篇 |
1996年 | 84篇 |
1995年 | 73篇 |
1994年 | 72篇 |
1993年 | 54篇 |
1992年 | 118篇 |
1991年 | 104篇 |
1990年 | 83篇 |
1989年 | 71篇 |
1988年 | 66篇 |
1987年 | 71篇 |
1986年 | 74篇 |
1985年 | 66篇 |
1984年 | 56篇 |
1983年 | 44篇 |
1982年 | 48篇 |
1981年 | 25篇 |
1980年 | 28篇 |
1979年 | 39篇 |
1978年 | 27篇 |
1977年 | 24篇 |
1975年 | 16篇 |
1974年 | 23篇 |
1973年 | 22篇 |
排序方式: 共有8187条查询结果,搜索用时 15 毫秒
101.
K. Tada M. Yoshimoto S. Nishimura K. Takahashi M. Makita T. Iwase S. Takahashi Y. Ito K. Hatake M. Ueno K. Nakagawa F. Kasumi 《European journal of surgical oncology》2004,30(10):1077-1083
AIM: Large multicenter, randomized trials have revealed the advantages of using tamoxifen for 5 years vs 2 years in breast cancer patients. The aim of this report is to confirm the optimal duration of tamoxifen administration in a study of Japanese breast cancer patients. METHODS: Japanese post-menopausal estrogen receptor-positive breast cancer patients treated with mastectomy were randomly assigned to either a 5-year or 2-year course of tamoxifen. The primary endpoint was disease-free survival, with secondary endpoints of overall survival and a reduction in the development of metachronous contra-lateral breast cancer. RESULTS: A total of 256 breast cancer patients were randomized to a 5-year or 2-year tamoxifen administration group. After a median follow-up time of 81 months, there were no significant differences seen in terms of disease-free or overall survival (p=0.65 and 0.56, respectively). Furthermore, the impact of the 5-year use of tamoxifen on the development of contra-lateral breast cancer did not reach statistical significance (p=0.0511). However, 5-year tamoxifen use was closely associated with gynaecological complications (p=0.0081). CONCLUSION: We could not show a beneficial effect of using tamoxifen for 5 years over 2 years in Japanese estrogen receptor-positive patients. This is likely due to the small number of patients enrolled in our study; however, racial disparity may influence this result. A reevaluation is necessary to study the advantages of the 5-year use of tamoxifen in the Japanese racial subgroup. 相似文献
102.
103.
Postoperative hyperperfusion syndrome in elderly patients with chronic subdural hematoma 总被引:3,自引:0,他引:3
Ogasawara K Ogawa A Okuguchi T Kobayashi M Suzuki M Yoshimoto T 《Surgical neurology》2000,54(2):155-159
BACKGROUND: Temporary acute agitated delirium is a frequent complication after surgery for chronic subdural hematoma (CSH) in elderly patients. To clarify the pathogenic mechanism underlying this complication, we measured cerebral blood flow before and after surgery in elderly patients with CSHs. METHODS: Twenty-seven patients aged 75 years or older with unilateral CSH underwent treatment involving a single burr hole craniostomy with continuous catheter drainage. Cerebral blood flow was measured using single photon emission computed tomography 1 day before surgery, and at 1 hour and 24 hours after surgery. Acute agitated delirium was diagnosed by the characteristic behavioral abnormality. RESULTS: SPECT imaging 1 hour after surgery demonstrated hyperperfusion in the cerebral cortex beneath the CSH in 14 patients (51.9%). Of these 14 patients, five showed acute agitated delirium a few hours after surgery that persisted for 10 to 12 hours. A hematoma was detected in the right hemisphere in all five patients. Hyperperfusion was significantly more intense in patients with acute agitated delirium both 1 hour and 24 hours after surgery than in patients (n = 9) without acute agitated delirium. Moreover, mean arterial blood pressure during the first postoperative hour was significantly higher in patients with acute agitated delirium. CONCLUSION: In elderly patients with CSH, intense and prolonged hyperperfusion after surgery induces temporary acute agitated delirium. This postoperative hyperperfusion syndrome is exacerbated by hypertension. 相似文献
104.
Evaluation of cell proliferation and apoptosis in Helicobacter pylori gastritis using an image analysis processor. 总被引:4,自引:0,他引:4
Yasuo Ohkura Tadashi Furihata Hitoshi Kawamata Masafumi Tabuchi Keiichi Kubota Akira Terano Taro Sakai Takahiro Fujimori 《Gastric cancer》2003,6(1):49-54
BACKGROUND: Infection of the gastric mucosa by helicobacter pylori is primarily responsible for gastritis, gastric ulcer, adenocarcinoma, and lymphoproliferative disorders. H. pylori appears to accelerate apoptosis and the proliferation of the gastric epithelium directly or indirectly. To precisely assess the proliferative and apoptotic profile of .H pylori-infected gastric mucosa, a quantitative imaging system is now required. METHODS: Fifty-two patients with H. pylori gastritis were the subjects of the study. Biopsy materials were taken from at least two sites (usually three to five sites) including the antrum and corpus. The grade of gastritis was evaluated by the updated Sydney System. The proliferative and apoptotic profile was examined by Ki-67 immunohistochemistry and by a terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling method. In addition, Ki-67-positive cells were quantitated by an image processor for analytical pathology (IPAP) system. RESULTS: H. pylori density and polymorphonuclear neutrophil activity were significantly decreased after H. pylori eradication ( P< 0.0001). Chronic inflammation (P< 0.0001) and lymphoid follicle numbers ( P < 0.0005) were also significantly decreased after the eradication. Glandular atrophy and intestinal metaplasia were slightly decreased after eradication, but the decrease did not reach the significant level. the Ki-67 labeling index was significantly decreased after the eradication P< 0.0001). The apoptosis index was also decreased after the eradication, but this decrease did not reach the significant level ( P = 0.06). CONCLUSION: our data suggest that the activation of proliferative cells and induction of apoptosis in the gastric mucosa is a response to H. pylori-induced mucosal damage. Moreover, IPAP may be a useful technology for evaluating the results of immunohistochemistry, and it could provide quantitative and reliable data for studying H. pylori gastritis. 相似文献
105.
Keiichi Ozono Sotaro Mushiake Toshikazu Takeshima Masahiro Nakayama 《Fetal and pediatric pathology》1997,17(2):249-258
We examined the placentas of 12 patients in whom congenital cytomegalovirus CMV infection was suspected from serological and or pathological evaluation. Seven patients died including four intrauterine deaths and five survived. On histological examination, the characteristic inclusion bodies were detected in only three placentas, and villitis with plasma cell infiltration was seen in eight placentas. Immunohistochemistry using a specific antibody against CMV improved the sensitivity of CMV detection 10 cases were positive . With the polymerase chain reaction PCR following the extraction of DNA from formaldehyde-fixed placenta samples, CMV DNA was detected in seven cases. All 12 subjects were diagnosed with CMV infection by additional Southern blot analysis after the PCR. CMV DNA was also detected by an in situ hybridization method in all cases. With current molecular biological techniques the placenta can be reliably used for the diagnosis of congenital CMV infection. 相似文献
106.
Keiichi Ichimura Masashi Sugasawa Ken-ichi Nibu Esao Takasago Kenji Hasezawa 《Auris, nasus, larynx》1997,24(4):391-397
We sometimes experience patients with persistent or progressive arytenoid edema, among which residual or recurrent cancer is often accompanied. Because it is difficult to distinguish tumour rest or recurrence from normal tissue sequelae in the early period after irradiation, it is important to know both the contributing factors for arytenoid edema, and the incidence of residual or recurrent tumours in patients with postirradiation laryngeal edema. We therefore reviewed the charts of 67 patients with early laryngeal carcinoma who had received a curative dose of irradiation in the last 5 years. Fourteen patients (20.9%) had moderate or severe laryngeal edema persisting for or developing at more than 3 months after completion of a course of definitive radiotherapy. The incidence was highest in supraglottic T2 disease, followed by glottic T2 tumour. Of the 14 patients with edema, six (42.9%) had persistent or recurrent disease. The primary disease was uncontrolled in 18 patients, 17 of whom received successful salvage surgery. In patients without residual tumours, the edema was usually moderate and resolved within a year, although four patients had chronic edema lasting more than a year after treatment. All four had supraglottic T2 lesions and received 70 Gy of X-ray. We also reviewed, for sake of comparison, the records of 38 patients treated with radiotherapy at doses of more than 40 Gy between l975 and 1980, when endoscopic microsurgery for laryngeal cancer was introduced as a primary part of treatment. The incidence of persistent or late developed edema over the period, though not significant, was 36.8%: nearly twice that of the last 5 years. Microscopic endolaryngeal surgical procedures seem to have been a causal factor for edema in this period. 相似文献
107.
Hiroyuki Suzuki Shichisaburo Abo Michihiko Kitamura Masaji Hashimoto Keiichi Izumi Kunihiko Terada Toshihiro Sugiyama 《Cancer investigation》1997,15(5):411-415
Gene amplification is a relatively frequent event in human malignant tumors and is believed to play an important role in tumor progression. The int-2 and erbB genes are amplified more frequently than any other genes in human esophageal cancer. In order to investigate the correlation between these two proto-oncogenes and the clinical behavior of esophageal cancer, we examined DNA amplification of int-2 and erbB and analyzed their relationship to clinicopathological variables. Genomic DNA was extracted from 21 esophageal squamous carcinomas and normal esopfiageal mucosa, as well as from 4 metastatic tumors. We used Southern blot analysis for detection of gene amplification. Amplification of int-2 was observed in 13 of 21 cases (62%) and in all the metastatic tumors (4/4; 100%). We found a significant correlation between amplification of int-2 and the length of the primary lesion. Amplification of erbB was detected in 3 of 18 patients (17%). All patients who showed amplification of erbB also demonstrated amplification of int-2. These results suggest that amplification of int-2 or neighboring genes on 11q may participate in tumor progression and metastasis in patients with esophageal squamous cancer. 相似文献
108.
Hiroshi Ochi Lecturer Keiichi Matsubara Assistant Yasuki Kusanagi Assistant Humiaki Taniguchi Assistant Masaharu Ito Professor 《BJOG : an international journal of obstetrics and gynaecology》1998,105(10):1118-1121
Objective To investigate the relation between placental embolisation and the diastolic notch in the uterine artery flow velocity waveform of pregnant ewes under general anaesthesia.
Methods Seven pregnant ewes at a gestation 16 to 17 weeks were anaesthesized and micro beads of gelfoam were injected into the uterine artery; changes in the uterine circulation were assessed by Doppler velocimetry.
Results Gelfoam embolisation reduced uterine blood flow in a dose-dependent manner, from a mean (95% CI) of 568 mL/min (495–641) to 159 mL/min (131–187) after the injection of 30 mg of gelfoam, and increased the uterine vascular resistance from 135 mmHg mine L−1 (103–167) to 498 mmHg mino L−1 (422–574). A diastolic notch in uterine artery flow velocity waveform was observed after 20 mg to 25 mg of gelfoam in two ewes and after injection of 30 mg of gelfoam in all seven animals. Injection of 30 mg of gelfoam increased the pulsatility index to 2–4 (1.9–2.9) from 0.6 (0.5–0.7). The mean uterine vascular resistance at the time of the appearance of a diastolic notch was 414 mmHg mine L−1 (377–451).
Conclusion These findings suggest that an elevated pulsatility index and the presence of a diastolic notch in the uterine artery flow velocity waveform are indicators of increased uterine vascular resistance and impaired uterine circulation. 相似文献
Methods Seven pregnant ewes at a gestation 16 to 17 weeks were anaesthesized and micro beads of gelfoam were injected into the uterine artery; changes in the uterine circulation were assessed by Doppler velocimetry.
Results Gelfoam embolisation reduced uterine blood flow in a dose-dependent manner, from a mean (95% CI) of 568 mL/min (495–641) to 159 mL/min (131–187) after the injection of 30 mg of gelfoam, and increased the uterine vascular resistance from 135 mmHg mine L
Conclusion These findings suggest that an elevated pulsatility index and the presence of a diastolic notch in the uterine artery flow velocity waveform are indicators of increased uterine vascular resistance and impaired uterine circulation. 相似文献
109.
Norito Takamura Toru Maruyama Etsuo Chosa Keiichi Kawai Yasuhiro Tsutsumi Yukie Uryu Keishi Yamasaki Tsuneo Deguchi Masaki Otagiri 《Drug metabolism and disposition》2005,33(4):596-602
To determine whether bucolome (5-n-butyl-1-cyclohexyl-2,4,6-trioxoperhydropyrimidine), a nonsteroidal anti-inflammatory agent, can reverse diuretic resistance of furosemide in patients with nephrotic syndrome, we examined the inhibitory effect of bucolome on the protein binding of furosemide in serum and urine. Bucolome significantly inhibited the protein binding of furosemide not only in serum but also in urine of preparation albumin (UPA), which mimics urinary albumin concentration in patients with nephrotic syndrome by ultrafiltration method. The binding percentage of furosemide to albumin was approximately 70% in UPA. With coadministration of bucolome to healthy volunteers, renal clearance of furosemide was increased, reflecting the increase of the free fraction of furosemide in serum. Furthermore, coadministration of bucolome caused a significant increase of urine volume and sodium concentration in urine. Even at higher urine levels of furosemide, the inhibitory effect of bucolome on the protein binding of furosemide in UPA remains constant, and changes in pH at weakly acidic pH levels (pH 5.5-6.5) did not alter the inhibitory effect of bucolome. Interestingly, coadministration of bucolome with furosemide in doxorubicin (Adriamycin)-induced nephrotic syndrome model rats alleviated the diuretic resistance. These results suggest that bucolome has a potent inhibitory effect on the protein binding of furosemide in the urine and can partially restore the diuretic response of furosemide in patients with nephrotic syndrome by increasing the free fraction of furosemide at the site of action. 相似文献
110.
Asaka Takahashi Hiroki Matsuoka Keiichi Yamada Yasushi Uda 《Food and chemical toxicology》2005,43(4):521-528
3-Allyl-5-substituted 2-thiohydantoins (ATH-amino acids) derived from allyl isothiocyanate and amino acids can inhibit the mutagenicity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in the Salmonella assay. In this report, we studied possible mechanisms for the inhibition using rat liver S9 in assays for ethoxyresorufin O-deethylase (EROD), a marker activity for cytochrome P450 1A (CYP1A), which activates heterocyclic amines, and the Salmonella assays with the direct-acting mutagen 2-hydroxyamino-3-methylimidazo[4,5-f]quinoline (N-hydroxy-IQ). Quantitative analysis of ATH-amino acids and IQ during incubation with rat liver S9 fraction by HPLC showed that ATH-amino acids could act as S9-inhibitors, thereby inhibiting metabolic activation of IQ. Among the tested ATH-amino acids, ATH-Phe, ATH-Trp, ATH-Leu and ATH-Val showed a dose-dependent inhibition of EROD activity. ATH-Gly, ATH-Glu, and ATH-Asp behaved as blocking agents toward N-hydroxy-IQ, but exhibited no inhibition of EROD activity. 相似文献