全文获取类型
收费全文 | 1557篇 |
免费 | 73篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 10篇 |
妇产科学 | 48篇 |
基础医学 | 174篇 |
口腔科学 | 105篇 |
临床医学 | 108篇 |
内科学 | 387篇 |
皮肤病学 | 128篇 |
神经病学 | 129篇 |
特种医学 | 26篇 |
外科学 | 194篇 |
综合类 | 13篇 |
预防医学 | 46篇 |
眼科学 | 15篇 |
药学 | 111篇 |
中国医学 | 4篇 |
肿瘤学 | 128篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 28篇 |
2020年 | 18篇 |
2019年 | 33篇 |
2018年 | 31篇 |
2017年 | 27篇 |
2016年 | 23篇 |
2015年 | 33篇 |
2014年 | 53篇 |
2013年 | 56篇 |
2012年 | 71篇 |
2011年 | 96篇 |
2010年 | 42篇 |
2009年 | 44篇 |
2008年 | 101篇 |
2007年 | 92篇 |
2006年 | 80篇 |
2005年 | 83篇 |
2004年 | 86篇 |
2003年 | 67篇 |
2002年 | 75篇 |
2001年 | 40篇 |
2000年 | 46篇 |
1999年 | 49篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1993年 | 8篇 |
1992年 | 18篇 |
1991年 | 22篇 |
1990年 | 15篇 |
1989年 | 29篇 |
1988年 | 23篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1972年 | 8篇 |
1970年 | 6篇 |
1969年 | 7篇 |
1968年 | 11篇 |
1967年 | 5篇 |
1966年 | 5篇 |
排序方式: 共有1634条查询结果,搜索用时 15 毫秒
11.
The placenta is an important functional unit for gas transfer between mother and fetus. The placental membrane, consisting of trophoblast layer interposed between maternal and fetal blood, plays an active role for intensity of respiration, but no morphological evidence has been documented. Until now, it has been reported that fetal growth retardation and increased fetal mortality rate usually could be seen at high altitude. In an attempt to find the cause of high perinatal mortality rate in Nepal, this study was undertaken to examine pathologically about 1000 Himalayan placentas obtained in Nepal and Tibet since 1977, and the results were compared with those of 5500 Japanese placentas at Saitama Medical School since 1990. In this study, characteristics of ultrastructural features of the Nepalese placental villi investigated in recent years are reported. (1) The gross characteristics of placental pathology in the Himalayan group were represented by marked subchorionic fibrin deposits and increased chorionic cysts in contrast to low incidence of intervillous thrombosis compared with those of the Japanese group. (2) As characteristics of histological findings of the placental villi between Himalayan and Japanese groups, the incidence of chorangiosis and chorangioma in the Himalayan group was significantly higher than that in the Japanese group. (3) Accompanying an increase of vasculosyncytial membrane (VSM) in the villi, thickness and separation of basement membrane of the syncytium in addition to increased apoptosis of syncytial cell nuclei were recognized. (4) As characteristic ultrastructural features of chorionic villi of Nepalese placentas, an increase of mitochondria and cystic formation of rough endoplasmic reticulum (rER), in addition to appearance of lamellar bodies similar to alveolar epithelial type II cell in organellae of the syncytium, were observed. These ultrastructural changes of the placental villous capillaries may be ascribed to hypevascularization caused by the chronic hypoxic state. It is, therefore, presumed that trophoblast cells may play an important role for gas transfer mecha-nism under such a hypoxic state at high altitude. 相似文献
12.
Joshi SN Gopalkrishna V Kumar BK Dutta S Nyaynirgune P Thakar M Tripathy S Mehendale S Paranjape R 《Journal of medical virology》2005,76(4):470-475
In view of the dual burden of HIV infection and cervical cancers in India, this study was undertaken to estimate the prevalence of Pap smear abnormalities and human papillomavirus infection among HIV-infected women. Consecutive HIV-infected women attending voluntary counseling testing clinics were enrolled. Written informed consent, demographic information, Pap smears, cervical swabs for HPV typing and a blood sample for CD4+ cell count were collected. Treatment for opportunistic and sexually transmitted infections and reproductive tract infections was provided. Women with Pap smear abnormality were referred for further intervention. Between January 2003 and May 2004, 287 HIV-infected women were enrolled. Pap smear abnormalities were seen in 6.3% women and were more common among women aged 30 and above (P=0.042) and those who had suffered from opportunistic infections (P=0.004). In multivariate analysis, Pap smear abnormalities were associated independently with opportunistic infections (P=0.02, AOR 3.8, 95% CI 1.2--11.5). Of the 100 random cervical specimens screened for HPV 16 and 18 genotypes, 33% (95 CI 23.9--43.1) were positive for HPV 16/18. Of the 122 patients who returned for a follow-up visit, 5 patients (4.1%) who did not have Pap smear abnormality at baseline, had developed Pap smear abnormality. The incidence of Pap smear abnormalities was 5.5 per 100 person year of follow-up. In order to prevent thousands of deaths due to cervical cancer in India, there is a need for strengthening the Pap smear screening program and HPV vaccine development. 相似文献
13.
I Ishiwata C Ishiwata M Soma H Ishikawa 《Journal of the National Cancer Institute》1987,78(4):667-673
A cell line designated "HUOCA-II" was established from a human ovarian clear cell adenocarcinoma. The HUOCA-II cells, which were oval, spindle, or polygonal and had neoplastic and pleomorphic features, grew in multiple layers without contact inhibition. The cell line grew fast (population doubling time, 24 hr), and 55 serial passages were carried out within 11 months. The chromosomal number ranged around 46, and no karyological abnormality was found in G-band karyotyping. When heterotransplanted into the subcutis of BALB/c nude mice, HUOCA-II cells produced a poorly differentiated clear cell adenocarcinoma. The tumor angiogenesis factor (TAF) of a molecular weight of about 14,000 was purified from the conditioned medium of HUOCA-II cells, and neovascularization was detected by bioassay with the use of the chorioallantoic membrane of a chick embryo. This TAF also stimulated the growth of endothelial cells in an in vitro culture system. 相似文献
14.
Multiple primary left ventricular myxomas with multiple intraventricular recurrences. 总被引:3,自引:0,他引:3
Y Soma S Ogawa S Iwanaga R Yozu M Kudo S Handa S Kawada H Sugiura 《The Journal of cardiovascular surgery》1992,33(6):765-767
A 23-year-old male was operated on for two primary left ventricular myxomas of the "complex" type. Ten months later, abnormal echo reappeared and reoperation was carried out to excise 2 recurrent myxomas in the left ventricle. Multiple foci were most likely responsible for the recurrence. No recurrence has been detected for 20 months postoperatively. This may be the first reported case of multiple primary left ventricular myxoma with multiple recurrences in the left ventricular cavity. 相似文献
15.
16.
A L Hamilton J P Eder A C Pavlick J W Clark L Liebes R Garcia-Carbonero A Chachoua D P Ryan V Soma K Farrell N Kinchla J Boyden H Yee A Zeleniuch-Jacquotte J Wright P Elliott J Adams F M Muggia 《Journal of clinical oncology》2005,23(25):6107-6116
PURPOSE: We performed a phase I study of a day (D) 1 and D4 bortezomib administration once every 2 weeks to determine the recommended phase II dose and toxicity profile, and the extent of 20S proteasome inhibition obtained. PATIENTS AND METHODS: Patients with solid tumors or lymphomas were treated with bortezomib at 0.25 to 1.9 mg/m2 on D1 and D4, every 2 weeks. 20S proteasome levels in blood were assayed at baseline and at 1, 4, and 24 hours postdose in cycle 1. RESULTS: On this D1 and D4 every 2 weeks' schedule, dose-limiting toxicity (DLT) was evident at the 1.75 and 1.9 mg/m2 dose levels, most commonly in patients receiving individual total doses > or = 3.0 mg. The main DLT was peripheral neuropathy evident at the higher doses and in patients previously exposed to neurotoxic agents. Other DLTs included diarrhea and fatigue; grade 3 thrombocytopenia was also noted. Reversible inhibition of 20S proteasome activity was dose dependent and best fit a total dose (mg) per fraction rather than mg/m2; 70% of baseline activity was inhibited by a dose of 3.0 to 3.5 mg given on D1 and on D4 every other week. Antitumor effects short of confirmed partial responses were observed in patients with melanoma, non-small-cell lung cancer, and renal cell carcinoma. CONCLUSION: Bortezomib (PS-341) is a novel antineoplastic agent that is well tolerated at doses not exceeding 3.0 mg (equivalent to 1.75 mg/m2), repeated on D1 and D4 every other week. This dose correlates with 70% inhibition of 20S proteasome activity. DLTs include neuropathy, fatigue, and diarrhea. 相似文献
17.
18.
A zeroth-order, non-diffracting Bessel beam, generated by picosecond laser pulses (1064 nm, 10 Hz, 30 ps) through an axicon, was utilized to perform pulse energy-dependent (12 mJ, 16 mJ, 20 mJ, 24 mJ) laser ablation of silver (Ag) substrates in air. The fabrication resulted in finger-like Ag nanostructures (NSs) in the sub-200 nm domain and obtained structures were characterized using the FESEM and AFM techniques. Subsequently, we employed those Ag NSs in surface-enhanced Raman spectroscopy (SERS) studies achieving promising sensing results towards trace-level detection of six different hazardous materials (explosive molecules of picric acid (PA) and ammonium nitrate (AN), a pesticide thiram (TH) and the dye molecules of Methylene Blue (MB), Malachite Green (MG), and Nile Blue (NB)) along with a biomolecule (hen egg white lysozyme (HEWL)). The remarkably superior plasmonic behaviour exhibited by the AgNS corresponding to 16 mJ pulse ablation energy was further explored. To accomplish a real-time application-oriented understanding, time-dependent studies were performed utilizing the AgNS prepared with 16 mJ and TH molecule by collecting the SERS data periodically for up to 120 days. The coated AgNSs were prepared with optimized gold (Au) deposition, accomplishing a much lower trace detection in the case of thiram (~50 pM compared to ~50 nM achieved prior to the coating) as well as superior EF up to ~108 (~106 before Au coating). Additionally, these substrates have demonstrated superior stability compared to those obtained before Au coating. 相似文献
19.
Akihiro Nakamura Ryoichi Sato Sanae Ando Natsuko Oana Eiji Nozaki Hideaki Endo Yoshiharu Miyate Jun Soma Go Miyata 《Fukushima journal of medical science》2021,67(1):27
Of the 47 prefectures in Japan, Iwate had the fewest cases of coronavirus disease 2019 (COVID-19), with the first diagnosis officially confirmed on July 28, 2020. A baseline serological survey of COVID-19 antibodies is essential to accurately evaluate an epidemic outbreak. The primary purpose of this study was to determine pre-epidemic prevalence of COVID-19 antibodies among healthcare workers, using two laboratory-based quantitative tests. In addition, a point-of-care (POC) qualitative test, rapid, simple, and convenient for primary care clinics, was compared with the laboratory-based tests. All antibody tests were performed on serum from 1,000 healthcare workers (mean age, 40 ± 11 years) in Iwate Prefectural Central Hospital, May 29-31, 2020. A COVID-19 case was defined as showing positive results in both laboratory-based quantitative tests. None of 1,000 samples had positive results in both of the laboratory immunoassays. The POC test showed positive results in 33 of 1,000 samples (3.3%) (95% confidence interval: 2.19-4.41), but no samples were simultaneously positive in both laboratory-based tests. In conclusion, COVID-19 cases were not serologically confirmed by a baseline control study of healthcare workers at our hospital in late May, 2020. Moreover, the POC qualitative test may offer no advantage in areas with very low prevalence of COVID-19, due to higher false-positive reactions compared with laboratory-based quantitative immunoassays. 相似文献
20.