全文获取类型
收费全文 | 4320篇 |
免费 | 176篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 77篇 |
妇产科学 | 50篇 |
基础医学 | 570篇 |
口腔科学 | 63篇 |
临床医学 | 257篇 |
内科学 | 1397篇 |
皮肤病学 | 33篇 |
神经病学 | 338篇 |
特种医学 | 111篇 |
外科学 | 534篇 |
综合类 | 20篇 |
预防医学 | 169篇 |
眼科学 | 34篇 |
药学 | 262篇 |
中国医学 | 12篇 |
肿瘤学 | 562篇 |
出版年
2023年 | 11篇 |
2022年 | 16篇 |
2021年 | 96篇 |
2020年 | 41篇 |
2019年 | 54篇 |
2018年 | 56篇 |
2017年 | 48篇 |
2016年 | 75篇 |
2015年 | 64篇 |
2014年 | 108篇 |
2013年 | 113篇 |
2012年 | 198篇 |
2011年 | 205篇 |
2010年 | 133篇 |
2009年 | 136篇 |
2008年 | 262篇 |
2007年 | 294篇 |
2006年 | 267篇 |
2005年 | 285篇 |
2004年 | 291篇 |
2003年 | 255篇 |
2002年 | 257篇 |
2001年 | 88篇 |
2000年 | 76篇 |
1999年 | 77篇 |
1998年 | 60篇 |
1997年 | 61篇 |
1996年 | 54篇 |
1995年 | 60篇 |
1994年 | 59篇 |
1993年 | 57篇 |
1992年 | 60篇 |
1991年 | 65篇 |
1990年 | 72篇 |
1989年 | 47篇 |
1988年 | 59篇 |
1987年 | 44篇 |
1986年 | 43篇 |
1985年 | 40篇 |
1984年 | 25篇 |
1983年 | 28篇 |
1982年 | 21篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 18篇 |
1973年 | 14篇 |
1969年 | 11篇 |
1968年 | 10篇 |
1967年 | 12篇 |
1966年 | 13篇 |
排序方式: 共有4537条查询结果,搜索用时 15 毫秒
1.
Heterozygous nonsense mutations near the C‐terminal region of IGF1R in two patients with small‐for‐gestational‐age‐related short stature 下载免费PDF全文
2.
Patricia A Wilkosz Sachiko Miyahara Oscar L Lopez Steven T Dekosky Robert A Sweet 《The American journal of geriatric psychiatry》2006,14(4):352-360
BACKGROUND: Psychotic symptoms in Alzheimer disease (AD+P) identify a heritable phenotype associated with more rapid cognitive decline. The authors have proposed that AD+P is itself a composite of a misidentification and a paranoid subtype with increased cognitive impairment restricted to the misidentification type. Most prior studies of the clinical correlates of AD+P have been limited, however, by the inclusion of prevalent cases. METHODS: Subjects with possible or probable AD or mild cognitive impairment (MCI) without psychosis at study entry were assessed at the time of initial presentation and then annually. Psychotic symptoms were assessed using the CERAD Behavioral Rating Scale. Survival analyses used Cox proportional hazard models with time-dependent covariates to examine the predictors of psychosis onset. RESULTS: A total of 288 subjects completed at least one follow-up examination. Mean duration of follow-up was 22.1 months. The incidence of psychosis was 0.19 per person-year. Cognitive impairment was associated with onset of psychosis, largely as a result of its association with onset of the misidentification, but not the paranoid, subtype. Including psychotropic medication use in the model revealed an association of antidepressant use with the onset of psychosis. This latter association appeared to arise from an underlying association between depression and the risk of psychosis onset rather than from antidepressant treatment. CONCLUSION: These findings are consistent with the hypothesis that the misidentification and the paranoid subtypes each define a more biologically homogeneous group than AD+P as a whole. Further exploration of the relationship between depressive symptoms and psychosis in patients with AD is warranted. 相似文献
3.
Mitsuru Takahashi Hidenobu Takahashi Tetsushi Itoh Masaharu Nomura Akihiko Ogata Sachio Maehara Harubumi Kato 《Annals of thoracic and cardiovascular surgery》2006,12(1):50-52
Postoperative empyema and aspergillosis were diagnosed in a 66-year-old man. Since non-operative therapy was not effective, we performed surgery. On the 8th postoperative day, a covered Ultraflex expandable stent (Boston Scientific, Galway, Ireland) was implanted to make a one-way airway for blocking a major air leak from a bronchopleural fistula causing respiratory distress. His general condition improved gradually, and he was discharged 30 days after stenting. In conclusion, we used a covered Ultraflex expandable stent to make an airway to block an air leak. This may be a new application for this stent. 相似文献
4.
CROSSOVER COMPARISON BETWEEN THE DEPRESSOR EFFECTS OF LOW AND HIGH WORK-RATE EXERCISE IN MILD HYPERTENSION 总被引:2,自引:0,他引:2
Eiichiro Tashiro Shin-ichiro Miura Manabu Koga Manabu Sasaguri Munehito Ideishi Masaharu Ikeda Hiroaki Tanaka Munehiro Shindo Kikuo Arakawa 《Clinical and experimental pharmacology & physiology》1993,20(11):689-696
1. The relationship between work-rate and the antihypertensive effect of exercise in hypertensives, and the mechanism of that effect, were investigated by a crossover clinical trial. 2. Ten mild hypertensives were randomly divided into two groups. One group performed low work-rate exercise (LWE) on a cycle ergometer for 10 weeks (blood lactate threshold; ~50% of maximum oxygen consumption [V?O2max]). After a 10 week interval without exercise training, these subjects were then switched to a high work-rate exercise (HWE) regimen (4 mmol/ L of blood lactate; ~75% of V?O2max) for another 10 weeks. In the other group, the order of exercise training was reversed. Since two patients withdrew from the protocol during HWE periods, statistical analysis was performed on the data from the remaining eight patients. There were no order effects observed in any of the data from the two groups. 3. During both LWE and HWE, resting blood pressure (BP) fell significantly after the initiation of exercise therapy (P<0.05). Furthermore, the overall effects of 10 weeks of LWE and HWE on BP were not significantly different. 4. The work-rate at the lactate threshold, which reflects physical fitness, had increased significantly by 16 W (P<0.01) after the LWE period and by 11 W (P<0.01) after the HWE. 5. During the LWE period, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 10 (P<0.05). In the HWE period, changes in haemodynamic and humoral variables were not significant. 6. Based on these findings, LWE is recommended for mild hypertensives because of its safety. 相似文献
5.
6.
Pathogenic role of connective tissue growth factor (CTGF/CCN2) in osteolytic metastasis of breast cancer. 总被引:5,自引:0,他引:5
7.
8.
Kuri Suzuki Daisuke Nishimi Hajime Morioka Masaharu Takanami 《International journal of urology》2007,14(4):370-372
The presence of blood in the ejaculate is called hematospermia or hemospermia. While often perceived as a symptom of little significance, hematospermia can cause great concern to men who experience it. We report an unusual case of hematospermia associated with pelvic arteriovenous malformation (AVM). A 60-year-old man who visited our hospital complaining of hematospermia and pollakisuria was found to have AVM and aneurysmal changes in the left side of the pelvis using computed tomography (CT). The patient was treated with steel coil embolization of the left inferior gluteal artery, and after the procedure the hematospermia and pollakisuria remained absent without flare-ups. 相似文献
9.
Hiroki Hamanaka Nobuaki Maeda Masaharu Noda 《The European journal of neuroscience》1997,9(11):2297-2308
Protein tyrosine phosphatase ζ (PTPζRPTPβ) is a proteoglycan-type receptor-like protein tyrosine phosphatase specifically expressed in the brain. In addition to the transmembrane form (PTPζ-A), the extracellular splice variant (PTPζ-S) occurs as a major soluble chondroitin sulphate proteoglycan in the brain. We prepared antibodies which specifically recognize PTPζ-A and -S, and analysed the carbohydrate structures on the two PTPζ isoforms in the developing chick brain. lmmunoprecipitation experiments using these antibodies revealed that almost all of the keratan sulphate recognized by a monoclonal antibody (5D4) was exclusively bound to PTPζ-A and PTPζ-S. Addition of keratan sulphate to these proteoglycans markedly increased from embryonic day (E) 11, in contrast to the addition of LeX and HNK-1 carbohydrates, which gradually increased during development in accordance with expression of the core proteins, suggesting that keratan sulphate modification plays some specific roles. Moreover, at the early embryonic stage keratan sulphate was observed only in several restricted regions, especially at boundary regions such as the roof plate of the tectum, the zona limitans intrathalamica in the diencephalon, and the mesencephalon-metencephalon boundary. At the mesencephalon-metencephalon boundary, keratan sulphate modification of PTPζ isoforms was specifically observed from E3 to E6 on a ring of cells encircling the neural tube and their radially oriented processes, which were identified as radial glial fibres. This expression pattern of keratan sulphate spatiotemporally corresponded well to the formation of the fovea isthmi, a groove separating the mesencephalon from the metencephalon. These results suggest that carbohydrates including keratan sulphate on PTPζ isoforms play important roles in brain development by modulating the cell-cell and/or cell-substrate interactions mediated by these molecules. 相似文献
10.
Tsuyoshi Shimizu Shigeki Ito Yujiro Kikuchi Masaharu Misaka Tetsuzo Hirayama Shin Ishimaru Akira Yamashina 《European journal of cardio-thoracic surgery》2004,25(4):578-584
OBJECTIVES: Graft failure has been reported when the arterial conduit, such as the internal thoracic artery (ITA) or the right gastroepiploic artery (GEA), is grafted to a lower grade coronary artery stenosis. The shear stress as a significant factor affecting graft patency was compared between the arterial conduit and the saphenous vein graft (SVG) after surgery. METHODS: In 101 patients, 40 ITAs, 27 GEAs and 34 SVGs were examined using a Doppler-tipped guide wire during postoperative angiography. The graft flow volume and shear stress were calculated from velocity and diameter data. The study grafts were classified according to the grade of native coronary artery stenosis: group L had more than 50 up to 75% stenosis, and group H had more than 75% stenosis. Group H consisted of 25 ITAs, 17 GEAs and 21 SVGs, while group L consisted of 15 ITAs, 10 GEAs and 13 SVGs. RESULTS: In group H, graft flow volume did not significantly differ among the ITA (34+/-11 ml/min), GEA (36+/-16 ml/min) and SVG (41+/-15 ml/min), and graft shear stress significantly (ITA vs. GEA P<0.0001; GEA vs. SVG P<0.01) differed among the ITA (16.0+/-4.8dyn/cm(2)), GEA (9.1+/-3.2dyn/cm(2)) and SVG (4.8+/-1.6dyn/cm(2)). In group L, flow volume was lower (P<0.001) in the ITA (18+/-6 ml/min) and GEA (13+/-8 ml/min) than in the SVG (35+/-16 ml/min), and shear stress was significantly (P<0.001) greater in the ITA (13.7+/-4.9dyn/cm(2)) than the GEA (5.6+/-2.0dyn/cm(2)) or SVG (4.6+/-2.0dyn/cm(2)). CONCLUSIONS: These data suggest that shear stress of the ITA is superior and maintained despite the flow volume being reduced by flow competition. Lower shear stress of the GEA for intermediate stenosis may be associated with the development of conduit failure. 相似文献