全文获取类型
收费全文 | 22587篇 |
免费 | 1057篇 |
国内免费 | 130篇 |
专业分类
耳鼻咽喉 | 155篇 |
儿科学 | 372篇 |
妇产科学 | 363篇 |
基础医学 | 3040篇 |
口腔科学 | 578篇 |
临床医学 | 1376篇 |
内科学 | 5797篇 |
皮肤病学 | 362篇 |
神经病学 | 1892篇 |
特种医学 | 871篇 |
外科学 | 3612篇 |
综合类 | 100篇 |
一般理论 | 2篇 |
预防医学 | 634篇 |
眼科学 | 605篇 |
药学 | 1684篇 |
中国医学 | 74篇 |
肿瘤学 | 2257篇 |
出版年
2023年 | 90篇 |
2022年 | 191篇 |
2021年 | 311篇 |
2020年 | 237篇 |
2019年 | 255篇 |
2018年 | 328篇 |
2017年 | 266篇 |
2016年 | 356篇 |
2015年 | 351篇 |
2014年 | 492篇 |
2013年 | 609篇 |
2012年 | 1016篇 |
2011年 | 1061篇 |
2010年 | 619篇 |
2009年 | 524篇 |
2008年 | 994篇 |
2007年 | 1052篇 |
2006年 | 967篇 |
2005年 | 1066篇 |
2004年 | 1132篇 |
2003年 | 1050篇 |
2002年 | 1061篇 |
2001年 | 850篇 |
2000年 | 893篇 |
1999年 | 811篇 |
1998年 | 338篇 |
1997年 | 257篇 |
1996年 | 224篇 |
1995年 | 192篇 |
1994年 | 191篇 |
1993年 | 175篇 |
1992年 | 568篇 |
1991年 | 491篇 |
1990年 | 493篇 |
1989年 | 492篇 |
1988年 | 439篇 |
1987年 | 383篇 |
1986年 | 366篇 |
1985年 | 366篇 |
1984年 | 269篇 |
1983年 | 198篇 |
1982年 | 108篇 |
1979年 | 173篇 |
1978年 | 133篇 |
1977年 | 130篇 |
1974年 | 96篇 |
1972年 | 94篇 |
1971年 | 97篇 |
1968年 | 98篇 |
1967年 | 93篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
M. Ito K. Hayashi Y. Ishida M. Uetani M. Yamada M. Ohki T. Nakamura 《Calcified tissue international》1997,60(1):11-15
For several different bone mineral measurements and various skeletal sites, we compared capability to discriminate between
women in various age decades with and without spinal fracture, and attempted to identify the most effective cutoff level in
discrimination of spinal fracture. The subjects were 88 women aged 50–59 years (including 32 with fracture), 95 women aged
60–69 years (including 54 with fracture), and 34 women aged 70–79 years (including 18 with fracture). Spinal trabecular and
cortical bone mineral density (BMD) were measured using quantitative computed tomography (CT), and spinal, radial (ultra-distal,
10% distal and 33% distal), and calcaneal BMD were measured by dual X-ray absorptiometry. These BMD values were obtained in
each subject on the same day. Three statistical techniques—Student's t-test, the logistic regression analysis, and the receiver operating characteristics (ROC) analysis— were applied and accuracy
was calculated using the various cutoff values. The capability to discriminate between women with and those without fracture
using these BMD values was different among the three age groups. In women aged 50–59 and 60–69 years, all measurements showed
good capabilities for discriminating women with fracture. In women aged 70–79 years, these measurements showed lower capability
than in those aged 50–59 and 60–69 years, but among them, the calcaneal and ultradistal radial BMD showed relatively good
capability. The 10% and 33% distal radial BMD values were not useful in the detection of the high risk women with fracture.
The cutoff BMD values for discrimination of women with fracture varied according to the sites and methods of measurement.
For each specific age group, the most suitable measurement methods and the appropriate skeletal sites should be considered,
and the effective cutoff values to discriminate those with fracture may differ according to the measurement methods, the skeletal
sites examined, and age.
Received: 5 February 1996 / Accepted: 18 June 1996 相似文献
72.
Mariko Hosono H. Kobayashi Ryota Fujimoto Kazushige Tsutsui Yoshihiko Kotoura Tadao Tsuboyama Hikaru Hayashi Takashi Nakamura Junji Konishi 《Skeletal radiology》1997,26(9):525-528
Objective. To clarify the MRI features of parasymphyseal insufficiency fractures of the os pubis. Design and patients. MRI was performed in four postmenopausal women with parasymphyseal insufficiency fractures. The diagnosis was confirmed with
plain films in every patient. T1-weighted and T2-weighted images were obtained in four patients using a 1.5-T unit. Postcontrast
T1-weighted imaging was also done in three patients. Results and conclusions. MRI of pubic parasymphyseal insufficiency fracture characteristically demonstrates a hyperintense mass lesion with a hypointense
rim on T2-weighted imaging, showing peripheral and septal enhancement after contrast administration. It is important to have
this entity in mind in patients with osteoporosis, especially in patients with a history of pelvic irradiation for malignant
disease, so as not to misinterpret it as a chondroid tumor or bone metastasis. 相似文献
73.
H J Jeon T Akagi Y Hoshida K Hayashi T Yoshino T Tanaka J Ito T Kamei K Kawabata 《Cancer》1992,70(10):2451-2459
BACKGROUND. The breast is rarely a primary site for extranodal malignant lymphoma. Most reported primary non-Hodgkin malignant lymphomas of the breast (PBL) are of B-cell phenotype. METHODS. Histologic and immunohistochemical analyses of seven patients with PBL and a statistical analysis of 152 patients with PBL reported in the Japanese literature were performed. RESULTS. Malignant lymphoma could not be predicted preoperatively with clinical and radiologic findings; breast carcinoma, fibroadenoma, and phyllodes tumor were the preoperative diagnoses. All patients were women; they ranged in age from 31 to 80 years (mean, 57.6 years). The right breast was involved initially in five patients. In four, only the breast was involved (Stage I), whereas in three, the ipsilateral axillary lymph nodes (Stage II) were involved at diagnosis. According to the Working Formulation, all patients belonged to the intermediate grade and were classified as having diffuse large cell (five patients) or mixed (two patients) lymphoma. Immunophenotypic analysis revealed that all patients had B-cell lymphoma. No patients had lymphoepithelial lesions, which is the characteristic feature in categorizing a lymphoma as a mucosa-associated lymphoid tissue (MALT) lymphoma. A statistical analysis of the patient reported in the Japanese literature has divided PBL into two types: a bilateral type that affects younger women and a unilateral type that has a broad age distribution, but preponderantly occurs in older women. The age and stage at diagnosis were significant prognostic factors in predicting the survival time, but the location and size of the tumor at initial presentation, histopathologic type, terminal leukemic manifestation, and treatment modality were not. CONCLUSIONS. This study indicates that most PBL are diffuse large cell lymphoma of B-cell phenotype and that the age and stage at diagnosis are significant prognostic factors. 相似文献
74.
Comparison of p53 expression in proximal and distal gastric cancer: Histopathologic correlation and prognostic significance 总被引:2,自引:0,他引:2
Huihuan Tang MD Shuichi Hokita MD PhD Xiangming Che MD Masamichi Baba MD PhD Kuniaki Aridome MD PhD Fumio Kijima MD Gen Tanabe MD PhD Sonshin Takao MD PhD Dr. Takashi Aikou MD PhD 《Annals of surgical oncology》1997,4(6):470-474
Background: The overexpression of p53 has been found to be correlated with prognosis of some carcinomas, including gastric cancer, but
no studies have reported on its relationship to the location of gastric cancer. In the present study, we compared the p53
expression of proximal and distal gastric cancer concerning histopathology and prognosis.
Methods: A total of 170 tumors in the patients with proximal (80 cases) and distal (90 cases) gastric cancer were studied by immunohistochemical
methods.
Results: p53 immunopositivity was detected in 28.8% of all tumors. The p53-positive expression in proximal gastric cancer was higher
than in distal gastric cancer (38.8% vs. 20.0%, p<0.05). A 5-year survival analysis showed that there is no significant difference
between tumors that are p53 positive and p53 negative. No correlation was found between p53 expression and histopathology
of gastric cancer.
Conclusion: p53 nuclear staining is not useful as a prognostic indicator or as a parameter in gastric cancer. 相似文献
75.
Estrogenic Induction of NADPH- Diaphorase Activity in the Preoptic Neurons Containing Estrogen Receptor Immunoreactivity in the Female Rat 总被引:1,自引:0,他引:1
Nitric oxide and estrogen have been shown to play a critical role in the control of female reproductive function. In order to determine an anatomical relationship between nitric oxide generating neurons and estrogen target neurons, NADPH-diaphorase histochemistry was combined with estrogen receptor immunohistochemistry in the female medial preoptic area. While only a few weakly stained neurons for NADPH-diaphorase were found in ovariectomized control rats, a drastic increase in NADPH-diaphorase activity was observed in the medial preoptic nucleus of estradiol-treated ovariectomized animals. The total number of NADPH-diaphorase neurons in the estradiol-treated group increased three-fold relative to controls, and more than 80% of those neurons contained estrogen receptor-immunoreactivity in their nuclei. Since neuronal NADPH-diaphorase is nitric oxide synthase, the present result suggests that nitric oxide synthase activity can be positively regulated by estradiol in neurons containing estrogen receptor in the female medial preoptic nucleus. 相似文献
76.
G M Fleischner R Morecki T Hanaichi H Hayashi N Quintana I Sternlieb 《Hepatology (Baltimore, Md.)》1991,14(3):422-425
A 56-yr-old woman with long-standing rheumatoid arthritis exhibited jaundice, pruritus and abdominal discomfort after 8 yr of periodic gold sodium thiomalate injections amounting to a cumulative dose in excess of 2.5 gm. Histopathological examination of the liver biopsy specimen showed submassive loss of parenchyma, collapse of reticulin and mixed cellular inflammatory infiltrates. Macrophages contained dark granules, which displayed the characteristics of aurosomes when examined by transmission electron microscopy and electron microprobe analysis. It is likely that hepatocellular injury occurred when the lysosomal storage capacity for gold was exceeded. 相似文献
77.
Late Effects of Childhood Acute Leukemia and Its Treatment 总被引:1,自引:0,他引:1
Masao Yamamoto M.D. Yoshitaka Fukunaga M.D. Ichiroh Tsukimoto M.D. Fumio Bessho M.D. Jun-ichi Akatsuka M.D. Ryohta Hosoya M.D. Shinpei Nakazawa M.D. Minoru Sakurai M.D. Kazuhiro Ueda M.D. Sumio Miyazaki M.D. Masaru Yokoyama M.D. Hideo Mugishima M.D. Kohzoh Nishimura M.D. 《Pediatrics international》1991,33(4):573-588
Late effects of childhood acute leukemia and its treatment were studied in 766 patients (684 ALL, 73 ANLL, and 9 others) in Japan who had remained in remission for more than 1 year after their first complete remission. Delayed adverse sequelae involve a wide variety of organs and their functions. Short stature was present in 2.61%, obesity in 3.79%, abnormalities of growth hormone secretion in 1.5%, delayed secondary sex characteristics in 1.5% of males and 0.6% of females, motor disturbances in 1.17%, sensory disturbances in 0.91%, intellectual and learning disabilities in 2.48%, abnormal findings in routine neurologic examinations in 1.31%, EEG abnormalities in 4.30%, brain CT abnormalities in 5.09% and cardiac dysfunction in 1.07%. Various other disorders were seen in 20 patients. Many of these delayed adverse sequelae are caused by or related to central nervous system prophylaxis and systemic combination chemotherapy. The results suggest that it is needed to improve therapeutic methods through the stratification of patients by risk factors and detailed analysis of prognostic factors. Moreover it is important to render medical and psychosocial support to long-term survivors of childhood leukemia through interactions between the patient, parents and medical staff. 相似文献
78.
79.
Akio Tanaka Motoyoshi Okamoto Dai Yoshizawa Shigeru Ito Patricia González Alva Fumio Ide Kaoru Kusama 《Journal of oral pathology & medicine》2007,36(7):400-404
BACKGROUND: Although it has been reported that ghost cells are present in odontomas, the generation mechanism of these cells is unclear. To evaluate the presence of ghost cells and involvement of the Wnt signaling pathway, we examined the expression of hard keratins, beta-catenin and Lef-1 in odontomas. METHODS: Sixty-nine cases of odontoma were examined immunohistochemically with the use of antibodies against human hair proteins, beta-catenin and Lef-1. RESULTS: Expression of hard keratins was found only in the cytoplasm of ghost cells in 46 (66.7%) of the 69 odontomas. Compound odontomas (78.8%) showed a higher incidence of ghost cells than complex odontomas (29.4%). Histopathologically, ghost cells were found within odontogenic epithelium adjacent to immature enamel and in the centre of Liesegang-ring-like calcified materials. Expression of beta-catenin and Lef-1 was observed in the cytoplasm and nucleus of odontogenic epithelial cells adjacent to the ghost cells in immature odontomas. CONCLUSION: These findings suggest that odontoma is a hard keratin-expressing tumor-like lesion, and that the Wnt signaling pathway may be involved in the formation of ghost cells in odontomas. 相似文献
80.
Yoshio Hayashi Kazuyoshi Ikuta Nobutaka Fujii Kunio Ezawa Shiro Kato 《Archives of virology》1989,105(1-2):129-135
Summary Only one peptide of CD4 (amino acid residues 70–132) among 16 synthetic peptide fragments selectively inhibited HIV-1 replication and HIV-1-induced syncytium formation. Several smaller peptides within this region did not show any activity, except for the peptide (86–132) which showed somewhat lower activity. 相似文献