全文获取类型
收费全文 | 98377篇 |
免费 | 8121篇 |
国内免费 | 3924篇 |
专业分类
耳鼻咽喉 | 1011篇 |
儿科学 | 2426篇 |
妇产科学 | 1798篇 |
基础医学 | 10731篇 |
口腔科学 | 2033篇 |
临床医学 | 8713篇 |
内科学 | 12812篇 |
皮肤病学 | 1476篇 |
神经病学 | 3985篇 |
特种医学 | 4260篇 |
外国民族医学 | 60篇 |
外科学 | 12972篇 |
综合类 | 15938篇 |
现状与发展 | 21篇 |
一般理论 | 1篇 |
预防医学 | 3514篇 |
眼科学 | 1192篇 |
药学 | 8016篇 |
58篇 | |
中国医学 | 3244篇 |
肿瘤学 | 16161篇 |
出版年
2024年 | 221篇 |
2023年 | 1483篇 |
2022年 | 3778篇 |
2021年 | 4585篇 |
2020年 | 3611篇 |
2019年 | 3536篇 |
2018年 | 3500篇 |
2017年 | 3360篇 |
2016年 | 3376篇 |
2015年 | 3748篇 |
2014年 | 6118篇 |
2013年 | 6268篇 |
2012年 | 5668篇 |
2011年 | 6225篇 |
2010年 | 5149篇 |
2009年 | 4985篇 |
2008年 | 4935篇 |
2007年 | 5080篇 |
2006年 | 4393篇 |
2005年 | 3960篇 |
2004年 | 3430篇 |
2003年 | 2930篇 |
2002年 | 2497篇 |
2001年 | 2241篇 |
2000年 | 1902篇 |
1999年 | 1738篇 |
1998年 | 1608篇 |
1997年 | 1487篇 |
1996年 | 1243篇 |
1995年 | 1090篇 |
1994年 | 946篇 |
1993年 | 711篇 |
1992年 | 601篇 |
1991年 | 516篇 |
1990年 | 408篇 |
1989年 | 363篇 |
1988年 | 372篇 |
1987年 | 278篇 |
1986年 | 238篇 |
1985年 | 317篇 |
1984年 | 286篇 |
1983年 | 169篇 |
1982年 | 233篇 |
1981年 | 192篇 |
1980年 | 157篇 |
1979年 | 154篇 |
1978年 | 104篇 |
1977年 | 76篇 |
1976年 | 59篇 |
1975年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Takakura Yoshinobu Fujita Takuya Hashida Mitsuru Sezaki Hitoshi 《Pharmaceutical research》1990,7(4):339-346
As part of the strategy for the design of macromolecular carriers for drug targeting, the disposition characteristics of macromolecules were studied in mice bearing tumors that served as target tissues. Eight kinds of macromolecules including four polysaccharides and four proteins with different molecular weights and electric charges were used; tissue distribution and tumor localization after intravenous injection were studied. Pharmacokinetic analysis revealed that the tissue radioactivity uptake rate index calculated in terms of clearance was different among the tested compounds; especially, the urinary radioactivity excretion clearances and the total hepatic radioactivity uptake clearances varied widely. Compounds with low molecular weights (approximately 10 kD) or positive charges showed lower tumor radioactivity accumulation; radioactivity was rapidly eliminated from the plasma via rapid urinary excretion or extensive hepatic uptake, respectively. On the other hand, large and negatively charged compounds, carboxymethyl dextran, bovine serum albumin, and mouse immunoglobulin G, showed higher radioactivity accumulation in the tumor (calculated total amounts were 15.6, 10.8, and 20.8% of the dose, respectively) and prolonged retention in the circulation. These results demonstrated that the total systemic exposure rather than the uptake rate index was correlated with total tumor uptake. Molecular weight and electric charge of the macromolecules significantly affected their disposition characteristics and, consequently, determined radioactivity accumulation in the tumor. It was concluded that a drug–carrier complex designed for systemic tumor targeting should be polyanionic in nature and larger than 70,000 in molecular weight. 相似文献
102.
HepatocelularCarcinomawithTumorThrombusinPortalVein:FindinginUltrasonography,ComputedTomography,AngiographyandChemoembolizati... 相似文献
103.
O. F. M. SELLEVOLD T. M. BERG K. A. REIN O. W. LEVANG O–J. IVERSEN K. BERGH 《Acta anaesthesiologica Scandinavica》1994,38(4):372-379
A prospective randomized study was performed to investigate the effect of surface coating with covalently endpoint–attached heparin (Carmeda Bio Active Surface) and reduced general heparinization on haematological indices and complement C5 activation. Care was taken to optimize the rheological design of the system using centrifugal pump and a closed system without venting or machine suction. Twenty patients scheduled for aortocoronary bypass grafting (EF > 0.5) participated in the study. Ten patients were randomized to be treated with heparin–coated equipment (CBAS) and reduced i.v. heparin (1.5 mg kg-1) while 10 patients treated with identical but noncoated equipment and full heparinization (3 mg–kg-1) served in a Control group. A vacuum suction was used to collect the blood from the operating field and it was autotransfused at weaning from extracorporeal circulation (ECC). Blood samples were obtained from the venous (precircuit) and arterial (postcircuit) side. We used a new and very specific method for detection of C5a based on monoclonal antibodies. The concentration of C5a was low in both groups during the operation but a significant increase was seen on days 1 and 2. In the Control group there was an increase from 10.2 ngml-1±1.2 to 27.5 ng ml-1 ± 4.8 on day 2 and in the CBAS group from 10.7 ng ml-1 ± 1.2 to 35.6 ng ml-1 ± 11.6 on day 2 (NS between groups). The granulocytes and total leukocyte count increased at the end of ECC and was maintained at the elevated level throughout the study period. The amount of free haemoglobin was high in the autotransfused blood in both groups. The present results confirm the feasibility of reducing general heparin when using heparin–coated systems but the study does not support the superiority of such coating with regard to biocompatibility in short procedures with a Theologically optimized circuit. The potential benefit from reduced heparin and protamine has not been fully evaluated. 相似文献
104.
G. Borkowski H. Sudhofft H. Luckhauptt S. Philippou H. Hildmann 《European journal of plastic surgery》1997,20(2):107-109
Dermatofibrosarcoma protuberans (DFSP) previously called Morbus Darier is an intermediate grade sarcoma with a fairly high rate of recurrence, it occurs most commonly on the trunk and extremities but may also occur in the head and neck region. Treatment of choice is wide excision. A 69-year-old female patient with a 57-year history of dermatofibrosarcoma protuberans is presented. The lesion appeared on the right forehead and both eyelids at the age of 12 years. The patient required 64 surgeries mostly for the head and neck lesions. 相似文献
105.
Tetsuji Kai Yang Il Kim Hirokazu Kitamura Katsunori Kawano Seigo Kitano 《Journal of Hepato-Biliary-Pancreatic Surgery》1997,4(4):423-430
There is a growing body of evidence that the cytokine, tumor necrosis factor-α (TNF-ga), plays an important role in the development
of hepatic ischemia/reperfusion injury. We found that the immunosuppressants, cyclosporine-A (CsA), azathioprine, and FK506,
have protective effects on such injury. The purpose of the present study was to elucidate mechanisms involved in these beneficial
effects of the immunosuppressant, CsA, on liver injury following cold preservation and transplantation, with special reference
to the suppression of TNF-α release. Rat livers were stored in Euro-Collins solution (EC) at 4°C for 6h and orthotopically
transplanted. The animals allotted to two groups: group A (untreated controls) and group B (CsA pretreatment of recipients).
CsA (10 mg/kg, p.o.) was given for 3 consecutive days preoperatively. CsA pretreatment of the recipients significantly improved
the 2-week survival rate (0/6 for group A, 3/6 for group B;P<0.05) and this was associated with a significant decrease in serum TNF-α levels 2h posttransplantation (group A, 69.8±15.7
pg/ml; group B, 22.8±6.8; mean±SEM;n=12 each;P<0.05) and amelioration of sinusoidal endothelial injury, assessed by electron microscopy. Plasma endotoxin levels following
reperfusion of the grafts were not altered by the CsA therapy. Morphologically, CsA pretreatment of the recipients did not
alter activation of Kupffer cells. CsA pretreatment of the recipient aids in preventing cold preservation/reperfusion injury
of the liver graft, possibly by modulating effects of TNF-α. 相似文献
106.
骨与关节肿瘤和瘤样病变1084例统计分析 总被引:5,自引:0,他引:5
目的:分析青海高原地区骨与关节肿瘤及瘤样病变的发病情况。方法:对1963~1995年10月的1084例骨与关节肿瘤及瘤样病变进行了统计分析。结果:良性骨肿瘤722例(66.61%),恶性骨与关节肿瘤249例(22.97%),瘤样病变113例(10.42%),良、恶性肿瘤之比为2.9∶1,男女之比为1.22∶1,好发年龄为11~30岁,好发部位为胫骨(27.3%),其次为股骨(21.8%)。良性骨肿瘤以骨软骨瘤(54.43%)、软骨瘤(21.19%)、骨巨细胞瘤(9.97%)多见。原发恶性骨肿瘤以骨肉瘤(33.3%)、软骨肉瘤(10.85%)、骨髓瘤(10.05%)多见。瘤样病变则以孤立性骨囊肿(46.01%)和骨纤维结构不良(30.97%)多见。结论:本组结果与国内文献对比有许多相似之处,但良性骨肿瘤与恶性骨肿瘤之比与国内文献有较大不同,可能与高原环境有关。 相似文献
107.
α-L-岩藻糖苷酶测定的临床应用 总被引:1,自引:0,他引:1
研究结果表明AFU测定对肝癌的诊断具有较高的敏感性和特异性,其价值优于AFP,两项指标联合检测可提高阳性检出率。动态监测有利于肝癌的早期诊断、鉴别诊断,并可作为转移、复发的指标,也可用于白血病及卵巢癌的诊断。 相似文献
108.
On the basis of earlier success in rat studies, chlorpromazine was evaluated as a probable agent for improving survival of random skin flaps in pigs. The aim was to exclude the possibility that the effect of the chlorpromazine is species specific and to find out if it is dose dependent. One hundred and five dorsally-based 12×4 cm flaps were raised unilaterally on the backs of 15 pigs. The animals were divided into three groups using 15 mg/kg chlorpromazine, 7.5 mg/kg chlorpromazine, and a saline-treated control group. Flaps in the control group averaged 40.57±3.17% necrosis, while flaps in the 15 mg/kg and 7.5 mg/kg chlorpromazine-treated groups averaged 31.53±4.77% and 11.47±2.22% necrosis respectively. These results demonstrate dose dependent beneficial affects of chlorpromazine and the survival of random skin flaps in the pig. Although ideal dose levels are still to be determined, flap survival improved with the prophylactic use of chlorpromazine at the lower 7.5 mg/kg dosage. 相似文献
109.
Kazue Shimmoto Shinichiro Ushigome Takashi Nikaido YaSUShi Kikuchi Naoaki Kobayashi Yohji Yamazaki 《Pediatric hematology and oncology》1991,8(2):147-157
A case is reported of Wilms' tumor associated with multiple pulmonary metastases histologically showing maturation of the tumor cells at 9 years after the resection of the primary tumor and intensive therapy. A huge tumor of a 22-month-old patient's right kidney was resected. The tumor was diagnosed as Wilms' tumor of mesenchymal type (stage 1), which consisted of predominantly immature mesenchymal tissue including rhabdomyoblasts, smooth muscle and fibrous tissue, and few blastemal and epithelial components. Intensive preoperative and postoperative chemotherapy with actinomycin D and vincristine and postoperative irradiation therapy totaling 16 Gy were carried out. The patient was regularly followed up uneventfully until 9 years after the surgery. On routine chest x ray at the age of 10 years 11 months, multiple pulmonary nodules were found. The excised nodules from the bilateral lungs disclosed similar histology, exclusively composed of dense collagen bundles and fibrocytes intermingled with mature striated muscle bundles. No immature tumor components were detected. The possible effect of intensive therapy in this maturation was stressed, although spontaneous benign differentiation of tumor cells cannot be excluded. 相似文献
110.
本文采用俯卧拍背法缓解胆绞痛41例,其中23例经此法治疗后疼痛立即消失(56.1%);15例明显缓解(36.6%);3例缓解不明显(7.3%)。具有操作简便、安全,易被患者接受,值得推广。 相似文献