全文获取类型
收费全文 | 4811篇 |
免费 | 548篇 |
国内免费 | 85篇 |
专业分类
耳鼻咽喉 | 70篇 |
儿科学 | 144篇 |
妇产科学 | 226篇 |
基础医学 | 629篇 |
口腔科学 | 101篇 |
临床医学 | 645篇 |
内科学 | 1275篇 |
皮肤病学 | 85篇 |
神经病学 | 331篇 |
特种医学 | 352篇 |
外科学 | 471篇 |
综合类 | 83篇 |
预防医学 | 193篇 |
眼科学 | 77篇 |
药学 | 388篇 |
中国医学 | 35篇 |
肿瘤学 | 339篇 |
出版年
2023年 | 28篇 |
2022年 | 74篇 |
2021年 | 136篇 |
2020年 | 98篇 |
2019年 | 156篇 |
2018年 | 150篇 |
2017年 | 131篇 |
2016年 | 161篇 |
2015年 | 179篇 |
2014年 | 180篇 |
2013年 | 267篇 |
2012年 | 287篇 |
2011年 | 249篇 |
2010年 | 234篇 |
2009年 | 200篇 |
2008年 | 235篇 |
2007年 | 259篇 |
2006年 | 219篇 |
2005年 | 199篇 |
2004年 | 166篇 |
2003年 | 130篇 |
2002年 | 134篇 |
2001年 | 105篇 |
2000年 | 111篇 |
1999年 | 99篇 |
1998年 | 86篇 |
1997年 | 96篇 |
1996年 | 93篇 |
1995年 | 79篇 |
1994年 | 53篇 |
1993年 | 74篇 |
1992年 | 66篇 |
1991年 | 53篇 |
1990年 | 45篇 |
1989年 | 78篇 |
1988年 | 63篇 |
1987年 | 65篇 |
1986年 | 28篇 |
1985年 | 49篇 |
1984年 | 37篇 |
1983年 | 39篇 |
1982年 | 25篇 |
1981年 | 26篇 |
1980年 | 33篇 |
1979年 | 19篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1975年 | 20篇 |
1971年 | 11篇 |
排序方式: 共有5444条查询结果,搜索用时 15 毫秒
51.
Chan Stephen W. W. Chien C. W. Wong Arnold Y. L. Pang Marco Y. C. 《Quality of life research》2021,30(6):1779-1791
Quality of Life Research - To translate and cross-cultural validate the PROMIS Pediatric-25 Profile 2.0 (PROMIS-25) into traditional Chinese, and to investigate its psychometric properties in... 相似文献
52.
止泻散敷脐治疗婴幼儿腹泻100例 总被引:1,自引:1,他引:0
0 引言 腹泻乃小儿最常见病 ,尤以 2岁以下婴幼儿最为常见 .年龄越小 ,发病率越高 ,且多在夏、秋季发病 .小儿患病后惧怕打针 ,服药以及输液 ,给治疗带来一些困难 . 12 a来 ,我们用自拟的止泻散敷脐治疗婴幼儿泄泻 ,效果良好 .1 对象和方法1.1 对象 1998- 0 6 / 1999- 10婴幼儿腹泻发病高峰期门诊病例 10 0 (男 6 6 ,女 34 )例 ,年龄 2月龄~ 5岁 .肠炎 5 8例 ,单纯消化不良 42例 . 6 7例曾多次治疗 ,33例初诊 .凡接受治疗之患儿 ,一律停止用其他药物 .1.2 方法 药物组成 :川椒 12 g,干姜 12 g,小茴香 12 g,白芷 2 0 g,吴茱萸 5 g,… 相似文献
53.
Yoshie Sugiura Andreas Woppmann George P. Miljanich Chien -Ping Ko 《Journal of neurocytology》1995,24(1):15-27
Summary Voltage-sensitive Ca2+ channels are essential to transmitter release at the chemical synapse. To demonstrate the localization of voltage-sensitive Ca2+ channels in relation to the site of transmitter release, mouse neuromuscular junctions were double-labelled with -bungarotoxin and a novel voltage-sensitive Ca2+ channel probe, SNX-260, a synthetic analog of -conopeptide MVIIC. Similar to -conopeptide MVIIC, biotinylated SNX-260 blocked nerve-stimulated transmitter release at the mouse neuromuscular junction. Fluorescently-tagged biotinylated SNX-260 labelled the nerve terminal which appeared thinner than and was outlined by acetylcholine receptor clusters as seen inen face view. This SNX-260 labelling was inhibited by preincubation with unconjugated SNX-260. Side-views of the neuromuscular junction indicated that the SNX-260 labelling was on the synaptic side facing the acetylcholine receptor rather than on the nonsynaptic side of the nerve terminal. This presynaptic binding was confirmed by the absence of SNX-260 labelling in denervated muscles following a nerve cut or disjunction after collagenase treatment. Confocal microscopy revealed spots of SNX-260 labelling that may correlate with active zones. The SNX-260 labelling pattern was not affected by preincubation with unconjugated SNX-111 (-conopeptide MVIIA), an N-type voltage-sensitive Ca2+ channel blocker. These findings suggest that SNX-260 is a novel probe for localizing non-N type voltage-sensitive Ca2+ channels and that these voltage-sensitive Ca2+ channels are localized near the transmitter release sites at the mammalian motor nerve terminal membrane. The results are consistent with the suggestion that non-N, probably P/Q type voltage-sensitive Ca2+ channels mediate evoked transmitter release at the mammalian neuromuscular junction. 相似文献
54.
BACKGROUND AND PURPOSE: The objective was to evaluate the results of high-resolution, fast-speed, section-interpolation MR angiography and digital subtraction angiography (DSA), thereby examining the potential use of a primary noninvasive screening test for intracranial aneurysms. METHODS: The images were obtained in 39 cerebral aneurysmal lesions from 30 patients with a time-of-flight MR angiographic technique using a 1.5-T superconducting MR system. The total image volume was divided into four slabs, with 48 partitions each. To save time, only 24 phase-encoded steps were measured and interpolated to 48. The parameters used included 30/6.4 (TR/TE), a flip angle of 25 degrees , a 160x512 matrix, a field of view of 150x200, 7 minutes 42 seconds of scan time, an effective thickness of 0.7 mm, and an entire thickness of 102.2 mm. Maximum intensity projection was used for the image analysis, and a multiplanar reconstruction technique was used for patients with intracranial aneurysms. RESULTS: Among 39 intracranial aneurysmal lesions in 30 patients, 21 were ruptured and 18 were unruptured. Twelve lesions were less than 2 mm in size, 12 were 3 to 5 mm, 12 were 6 to 9 mm, and three were larger than 10 mm. At initial examinations, 38 of 39 aneurysmal lesions were detected by both MR angiography and DSA, with 97% sensitivity. In confirming aneurysms in neck and parent vessels, multiplanar reconstruction was successful in detecting all 39 aneurysms, whereas MR angiography was successful in detecting 27 (69%) and DSA was successful in detecting 32 (82%) of the lesions. CONCLUSION: High-resolution MR angiography with a section-interpolation technique showed equal results to those of DSA for the detection of intracranial aneurysms and may be used as a primary noninvasive screening test. In the evaluation of aneurysms in neck and parent vessels, the concurrent use of MR angiography and multiplanar reconstruction was far superior to the use of either MR angiography or DSA alone. 相似文献
55.
Osteochondroma and secondary synovial osteochondromatosis 总被引:1,自引:0,他引:1
Secondary synovial osteochondromatosis (SOC) is a rare disorder caused by a variety of joint disorders. Two unusual cases
of secondary SOC are presented. The first patient is a 43-year-old man with extensive SOC developing within a bursa surrounding
an osteochondroma of the pubic bone. The second patient is a 23-year-old man who developed florid and progressive SOC of his
hip joint following excision of a femoral neck osteochondroma. SOC recurred despite three excisions over a 15-month period.
Imaging was useful in pre-operative diagnosis of bursal SOC in the first patient and in detecting multiple recurrences in
the second patient. Both cases illustrate prominent SOC developing secondary to osteochondroma. The different hypotheses regarding
bursal and secondary SOC are reviewed.
Received: 8 October 1998 Revision requested: 28 October 1998 Revision received: 13 November 1998 Accepted: 16 November 1998 相似文献
56.
Chorvat RJ Bakthavatchalam R Beck JP Gilligan PJ Wilde RG Cocuzza AJ Hobbs FW Cheeseman RS Curry M Rescinito JP Krenitsky P Chidester D Yarem JA Klaczkiewicz JD Hodge CN Aldrich PE Wasserman ZR Fernandez CH Zaczek R Fitzgerald LW Huang SM Shen HL Wong YN Chien BM Arvanitis A 《Journal of medicinal chemistry》1999,42(5):833-848
The synthesis and CRF receptor binding affinities of several new series of N-aryltriazolo- and -imidazopyrimidines and -pyridines are described. These cyclized systems were prepared from appropriately substituted diaminopyrimidines or -pyridines by nitrous acid, orthoester, or acyl halide treatment. Variations of amino (ether) pendants and aromatic substituents have defined the structure-activity relationships of these series and resulted in the identification of a variety of high-affinity agents (Ki's < 10 nM). On the basis of this property and lipophilicity differences, six of these compounds (4d,i,n,x, 8k, 9a) were initially chosen for rat pharmacokinetic (PK) studies. Good oral bioavailability, high plasma levels, and duration of four of these compounds (4d,i,n,x) prompted further PK studies in the dog following both iv and oral routes of administration. Results from this work indicated 4i,x had properties we believe necessary for a potential therapeutic agent, and 4i1 has been selected for further pharmacological studies that will be reported in due course. 相似文献
57.
Tissue potassium,selenium, and iron levels associated with gastric cancer progression 总被引:4,自引:0,他引:4
Chew-Wun Wu MD Yuan-Yaw Wei BS Chin-Wen Chi PhD Wing-Yiu Lui MD Fang-Ku P'eng MD Chien Chung PhD 《Digestive diseases and sciences》1996,41(1):119-125
The contents of 10 minor and trace elements in histologically confirmed gastric adenocarcinomas and their corresponding normal gastric mucosal tissues obtained from 39 patients at the time of gastric resection were simultaneously determined by instrumental neutron activation analysis. Specimens were irradiated by reactor neutrons and subsequently subject to direct analysis using a high-resolution HPGe -spectrometer. Univariate analysis revealed that gastric cancer tissues had significantly higher concentrations of Fe, K, Mg, Na, Rb, Se, and Zn than normal gastric mucosal tissues. However, multivariate analysis found that Fe, K, and Se were independent elements that associated with gastric cancer. Upon further evaluation of their clinical significance, we found a high tissue K level was related to lymphatic duct metastasis. High Se tissue levels were linked to intestinal type adenocarcinoma. A positive correlation was found between high Fe levels and vascular involvement. These findings suggest that Fe and K are associated with gastric cancer progression. Se is involved in carcinogenesis of stomach in high-risk areas. The mechanisms that underlie the corresponding pathohistological features deserve further study. 相似文献
58.
59.
Stenosis phantoms were created to study the ability of "black blood" methods to image a vessel stenosis in the presence of pulsatile flow. Black blood images were acquired with a modified TurboFLASH (fast low-angle shot) method that eliminates flow signal by applying a set of prepulses before segmented data acquisition. With this high-speed approach, imaging can be completed within 16 seconds. This technique was compared with conventional spin-echo black blood, gradient-echo black blood, and gradient-echo bright blood methods. Loss of flow signal, which extended beyond the site of the stenosis, was seen on the gradient-echo bright blood images. The pattern of signal loss varied with the type of stenosis. Flow voids were achieved with spin-echo black blood imaging; however, substantial ghosting artifacts were seen. With gradient-echo black blood imaging, it was difficult to eliminate all flow signal, particularly for in-plane flow. The modified TurboFLASH method produced high-quality black blood images in a fraction of the time needed for spin-echo imaging. It showed no ghosting artifacts even in the presence of pulsatile flow. 相似文献
60.
Down-Regulation of Osteoblastic Cell Differentiation by Epidermal Growth Factor Receptor 总被引:6,自引:0,他引:6
The role of epidermal growth factor receptors (EGF-R) in osteogenic cell differentiation was investigated using preosteoblastic
MC3T3-E1 (MC3T3) cells and osteoblast-like ROS 17/2.8 (ROS) cells. When cultured in the presence of β-glycerophosphate (GP)
and ascorbic acid (AA), MC3T3 cells underwent spontaneous differentiation into osteoblasts which was confirmed as they expressed
osteoblast markers such as alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OC). Interestingly, the number
of EGF-binding sites decreased during their differentiation into osteoblasts, and the osteogenic protein-1 (OP-1) treatment,
which accelerated their differentiation, lowered the number of EGF-binding sites even further. On the other hand, ROS cells
with high expression levels of osteoblast markers and no EGF-R, after being transfected with human EGF-R cDNA (EROS cells),
expressed numerous EGF-binding sites as well as EGF-R mRNA and protein; in the process, they ceased to express osteoblast
markers, indicating their dedifferentiation into osteoprogenitor cells. Both MC3T3 and EROS cells showed increased cell growth
in response to EGF, whereas ROS cells did not. These results imply that the EGF/EGF-R system in osteogenic cells has a crucial
function in osteoblast phenotype suppression and osteogenic cell proliferation. 相似文献