全文获取类型
收费全文 | 22343篇 |
免费 | 1080篇 |
国内免费 | 149篇 |
专业分类
耳鼻咽喉 | 202篇 |
儿科学 | 427篇 |
妇产科学 | 231篇 |
基础医学 | 3022篇 |
口腔科学 | 481篇 |
临床医学 | 1503篇 |
内科学 | 5824篇 |
皮肤病学 | 413篇 |
神经病学 | 1953篇 |
特种医学 | 819篇 |
外科学 | 3635篇 |
综合类 | 102篇 |
预防医学 | 625篇 |
眼科学 | 506篇 |
药学 | 1326篇 |
中国医学 | 45篇 |
肿瘤学 | 2458篇 |
出版年
2023年 | 133篇 |
2022年 | 232篇 |
2021年 | 519篇 |
2020年 | 257篇 |
2019年 | 399篇 |
2018年 | 527篇 |
2017年 | 411篇 |
2016年 | 508篇 |
2015年 | 520篇 |
2014年 | 668篇 |
2013年 | 803篇 |
2012年 | 1337篇 |
2011年 | 1517篇 |
2010年 | 831篇 |
2009年 | 671篇 |
2008年 | 1293篇 |
2007年 | 1480篇 |
2006年 | 1385篇 |
2005年 | 1474篇 |
2004年 | 1413篇 |
2003年 | 1427篇 |
2002年 | 1322篇 |
2001年 | 313篇 |
2000年 | 265篇 |
1999年 | 326篇 |
1998年 | 303篇 |
1997年 | 235篇 |
1996年 | 205篇 |
1995年 | 220篇 |
1994年 | 168篇 |
1993年 | 149篇 |
1992年 | 216篇 |
1991年 | 215篇 |
1990年 | 172篇 |
1989年 | 185篇 |
1988年 | 139篇 |
1987年 | 135篇 |
1986年 | 115篇 |
1985年 | 103篇 |
1984年 | 83篇 |
1983年 | 68篇 |
1981年 | 50篇 |
1980年 | 47篇 |
1979年 | 59篇 |
1974年 | 72篇 |
1973年 | 52篇 |
1972年 | 46篇 |
1970年 | 48篇 |
1969年 | 52篇 |
1968年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 494 毫秒
81.
We report a case of parkinsonism induced by long term administration of an oral contraceptive. A 38-year-old woman complained of easily stumbling, démarche à petit pas and fatiguability in her lower extremities since January, 1991. When examined on April 5, 1991, she explained taking an oral contraceptive for 7 years on her doctor's recommendation after two times artificial abortions. Her facial expression was mask-like and body was bent forward with knee joints flexed and arms flexed at elbow joints. She had frozen gait with inactive pendulousness of the arms. We could find her muscle rigidity in both upper and lower extremities, especially in her right side extremities. A brain MRI finding was lacunar infarction which proton density weighted and T2-weighted MR images showed small patches of high-signal intensities in white matter of the bilateral frontal lobes and in left periventricular white matter. Her symptoms improved after stopping administration of the oral contraceptive and starting combination therapy with nicergoline and bromocriptine. She had some leg fatiguability at the onset of her next menstruation in May, but it was much less than her previous condition. When her menstruation terminated, those symptoms disappeared and it was possible to stop the administration of bromocriptine and nicergoline, and her symptoms have improved. 相似文献
82.
Kenji Kurosawa Kiyoshi Imaizumi Mitsuo Masuno Yoshikazu Kuroki 《American journal of medical genetics. Part A》1994,51(2):143-146
Limb-body wall complex is a malformation of body and limbs with craniofacial defects. We describe here the epidemiology of this complex using the population-based registry data in the Kanagawa Birth Defects Monitoring Program during the period 1982–1991. Eleven infants (11/428,599 births) with the complex were ascertained in the study. The incidence and spectrum of the defects observed in our cases were similar to those of other studies. The parental ages in the study group were not significantly different from those in the general population. No teratogenic agents and factors were identified in the present study. Most cases were diagnosed prenatally. © 1994 Wiley-Liss, Inc. 相似文献
83.
Kimiyoshi Ozawa Kenji Hashimoto Takashi Kishimoto Eiji Shimizu Hiroshi Ishikura Masaomi Iyo 《Neuropsychopharmacology》2006,59(6):546-554
BACKGROUND: Maternal viral infection is associated with increased risk for schizophrenia. It is hypothesized that the maternal immune response to viruses may influence fetal brain development and lead to schizophrenia. METHODS: To mimic a viral infection, the synthetic double strand RNA polyriboinosinic-polyribocytidilic acid (poly I:C) was administered into pregnant mice. Behavioral evaluations (thigmotaxis, methamphetamine [MAP]-induced hyperactivity, novel-object recognition test [NORT]), sensorimotor gating (prepulse inhibition [PPI]), and biochemical evaluation of the dopaminergic function of the offspring of phosphate-buffered saline (PBS)-treated dams (PBS-mice) and that of poly I:C-treated dams (poly I:C-mice) were examined. RESULTS: In juveniles, no difference was found between the poly I:C-mice and PBS-mice. However, in adults, the poly I:C-mice exhibited attenuated thigmotaxis, greater response in MAP-induced (2 mg/kg) hyperlocomotion, deficits in PPI, and cognitive impairment in NORT compared with the PBS-mice. Cognitive impairment in the adult poly I:C-mice could be improved by subchronic administration of clozapine (5.0 mg/kg) but not haloperidol (.1 mg/kg). Increased dopamine (DA) turnover and decreased receptor binding of D2-like receptors, but not D1-like receptors, in the striatum were found in adult poly I:C-mice. CONCLUSIONS: Prenatal poly I:C administration causes maturation-dependent increased subcortical DA function and cognitive impairment in the offspring, indicating a neurodevelopmental animal model of schizophrenia. 相似文献
84.
Jiro Okochi Kenji Toba Tai Takahashi Kozo Matsubayashi Masanori Nishinaga Ryutaro Takahashi Takashi Ohrui 《Geriatrics & Gerontology International》2006,6(4):223-227
Background: The aim of this study is to construct a simple screening test for the risk of falls in community-dwelling elder persons.
Methods: A total of 1378 community-dwelling people aged 65 years and older in five different communities in Japan were asked to answer a self rated questionnaire including 22 items covering physical, cognitive, emotional and social aspects of functioning and environmental factors. At a six-month follow-up, the outcome of fall occurrence and the number of falls was ascertained by social workers, health visitors or nurses.
Results: Five out of 22 items were selected using a logistic regression model. Using this five-item version, a screening test was constructed, and at the best cut-off point, the sensitivity and specificity were 68% and 70%, respectively. The validity of this scale was tested on persons with cognitive dysfunction.
Conclusion: The simplicity and the predictive validity of the screening test support the use of this test in health check ups or general outpatient facilities. 相似文献
Methods: A total of 1378 community-dwelling people aged 65 years and older in five different communities in Japan were asked to answer a self rated questionnaire including 22 items covering physical, cognitive, emotional and social aspects of functioning and environmental factors. At a six-month follow-up, the outcome of fall occurrence and the number of falls was ascertained by social workers, health visitors or nurses.
Results: Five out of 22 items were selected using a logistic regression model. Using this five-item version, a screening test was constructed, and at the best cut-off point, the sensitivity and specificity were 68% and 70%, respectively. The validity of this scale was tested on persons with cognitive dysfunction.
Conclusion: The simplicity and the predictive validity of the screening test support the use of this test in health check ups or general outpatient facilities. 相似文献
85.
Koichi Tanaka Kazue Ozawa Satoshi Teramukai Yasutsugu Takada Hiroto Egawa Satoshi Kaihara Yasuhiro Fujimoto Yasuhiro Ogura Mureo Kasahara Masako Ono Hiroshi Sato Kenji Takai Masanori Fukushima Nagahiro Minato 《Liver transplantation》2006,12(5):792-800
The primed status of T cells is markedly different among liver transplant recipients, due to a lifetime of antigen exposure and reduced thymopoiesis by aging, and diseases. This study aims to characterize the preoperative immunological status of CD8+ T cell subpopulations and relate it to the outcome for liver transplant recipients. We classified 112 liver transplant recipients into 5 groups, based on hierarchical clustering of the CD8+CD45 isoform proportion of T cells. In Groups I and II (pediatric), the naive T cell proportion was more than 50%. In adult recipients, Group III was characterized by a naive T cell proportion of 50%, Group IV had the greatest effector/memory T cells (EM), and Group V had the greatest proportion of effector T cells. In Groups IV and V, the effector T cell proportion was considerably higher, and was accompanied by marked downregulation of the CD27+CD28+ subsets and upregulation of interferon gamma (IFN)-gamma, tumor necrosis factor-alpha, and perforin expression. Group V recipients tended to be complicated postoperatively, with a significantly reduced survival rate (1 yr, 66.8%) and markedly reduced Eastern Cooperative Oncology Group performance status. 相似文献
86.
Shinji Homma Kenji Satoh Hitoshi Matsuo Minoru Yagi Jun Hasegawa Tomoyuki Maruta Naozumi Watanabe Tsuneo Iiai Katsuyoshi Hatakeyama 《Journal of Smooth Muscle Research》2004,40(6):271-280
Electrogastrograms (EGGs) were recorded in patients both before and after receiving proximal gastrectomy plus jejunal interposition (PGJI) or just after receiving total gastrectomy plus jejunal interposition (TGJI). Intraluminal pressure was also recorded in some postoperative patients. The EGG 3 cpm component (2.5-4.9 cpm) remained after PGJI, but subsequently decreased with a significant reduction in the preoperative to postoperative ratio of the 3 cpm components (P<0.05). The mean frequency of the 3 cpm components increased significantly after PGJI (P<0.05) and its instability factor increased. The EGG 10 cpm components became relatively dominant compared to other frequency components in 2 out of 8 of patients having PGJI but the mean amplitude of 10 cpm decreased. In TGJI patients, only the 10 cpm component was conspicuous in EGG as in the case of total gastrectomy and Roux en Y anastomosis procedures. The spectral frequencies of intraluminal pressure in the interposed jejunum were similar to the EGG of 10 cpm components both in the case of PGJI and TGJI patients. In conclusion, surface EGG could record the electrical activities of the interposed jejunum more easily in patients having had TGJI than in PGJI. 相似文献
87.
88.
A model of hematuria was established in rabbits. An accelerated form of unilateral Masugi nephritis was induced in 10 New Zealand white rabbits by an intravenous injection of duck antirabbit kidney serum and by ligating the left renal artery immediately after the injection of the antibody. All 10 rabbits became hematuric 1-2 weeks after the injection of the antibody and red blood cell (RBC) casts were found in the urinary sediment of all these animals. An ultrastructural examination of renal glomeruli by transmission electron microscopy revealed the transcapillary passage of polymorphonuclear leukocytes through the gaps of the glomerular basement membrane (GBM). RBC were found in the urinary space in 50% of the glomeruli observed by scanning electron microscopy (SEM) and the passage of leukocytes and RBCs through the glomerular capillary wall was also observed. Gaps in the GBM became clearer after the removal of cellular components by detergents. In control rabbits, no RBCs could be observed in the urinary space, and isolated GBM were intact by SEM. These data further support the hypothesis that in rabbit Masugi nephritis hematuria is a result of the passage of RBCs through gaps in the GBM. 相似文献
89.
K Iwahashi T Ota H Sato H Kanda T Sugimoto M Okada K Nakamura 《Journal of cardiology》1992,22(4):651-659
To determine the relative superiority of a prosthesis in the mitral position, in vivo hemodynamics were examined by Doppler echocardiography, and the results were compared with other types of mechanical mitral valves including 63 Bj?rk-Shiley convexo-concave (BS) values, 30 Duromedics (DM) valves, and 58 Medtronic Hall (MH) valves. For this comparison, the following indices were evaluated: peak velocity of mitral flow (PV), mitral valve orifice area (MVA), mitral valvular regurgitation, New York Heart Association (NYHA) classification, pulmonary capillary wedge pressure (PC), cardiac index (CI) and valve-related complications. On Doppler echocardiograms, PV ranged from 1.2 to 2.0 m/sec with a mean of 1.6 m/sec. There was no evident relationship between the PV and the valve size in each type of prosthesis, and no significant difference in the PVs among the valves. The mean MVA was 2.6 cm2 (25 mm DM, 25 mm MH), which was regarded satisfactory from a clinical standpoint. MVA increased with the increase in the valve size in all types of valves, and of all sizes, MVA was larger in the DM and MH groups than in the BS group. Similarly, the incidence of valvular regurgitation was relatively low in all groups, and the degree of regurgitation proved to be grade II or less in all cases. As for the clinical results, clinical symptoms (NYHA) and hemodynamic states (PC, CI) improved postoperatively, with the differences among the types of prosthetic valves being insignificant. The incidences of thromboembolism, valvular thrombosis, valve failure and prosthetic endocarditis were relatively low in all groups.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
90.
Masashi Kimura M.D. Kenji Shirakura M.D. Atsushi Hasegawa M.D. Yasukazu Kobayashi M.D. Eiichi Udagawa M.D. 《Arthroscopy》1992,8(4):419-423
An arthroscopic and anatomical investigation was performed to define the abnormal conditions of the popliteal tendon area in a lateral meniscus. Arthroscopic findings for 100 patients and anatomical observations of 10 amputated knees were analyzed. Five of the 10 dissected menisci were also examined histologically. Menisco-tibial coronary ligaments were classified into two types, as follows: type I--a coronary ligament covering an entire popliteal tendon beneath the meniscus; type II--a popliteal tendon visible beneath the meniscus through defects of the coronary ligament. Twenty-one of 100 cases were classified as type I, and 79 were classified as type II. Three of the 10 anatomical dissections were type I, and the remaining 7 were type II. Menisci in which the type I coronary ligaments were thought to be torn and menisci with type II coronary ligaments showed a rather marked mobility, but no conclusion could be reached. 相似文献