全文获取类型
收费全文 | 3618篇 |
免费 | 259篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 96篇 |
妇产科学 | 77篇 |
基础医学 | 685篇 |
口腔科学 | 92篇 |
临床医学 | 224篇 |
内科学 | 893篇 |
皮肤病学 | 98篇 |
神经病学 | 303篇 |
特种医学 | 73篇 |
外科学 | 438篇 |
综合类 | 21篇 |
一般理论 | 3篇 |
预防医学 | 212篇 |
眼科学 | 88篇 |
药学 | 283篇 |
中国医学 | 9篇 |
肿瘤学 | 284篇 |
出版年
2024年 | 6篇 |
2023年 | 45篇 |
2022年 | 124篇 |
2021年 | 174篇 |
2020年 | 102篇 |
2019年 | 119篇 |
2018年 | 143篇 |
2017年 | 103篇 |
2016年 | 104篇 |
2015年 | 141篇 |
2014年 | 150篇 |
2013年 | 170篇 |
2012年 | 265篇 |
2011年 | 254篇 |
2010年 | 160篇 |
2009年 | 126篇 |
2008年 | 243篇 |
2007年 | 214篇 |
2006年 | 214篇 |
2005年 | 223篇 |
2004年 | 190篇 |
2003年 | 174篇 |
2002年 | 139篇 |
2001年 | 26篇 |
2000年 | 22篇 |
1999年 | 33篇 |
1998年 | 34篇 |
1997年 | 29篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1967年 | 3篇 |
排序方式: 共有3904条查询结果,搜索用时 15 毫秒
71.
72.
Yuri Noda Yuko Nakanishi Ayaka Nishimae Hiroyo Takahashi Chiya Oshiro Hideo Inaji Masaru Yamasaki 《Diagnostic cytopathology》2020,48(7):652-656
Solid basaloid adenoid cystic carcinoma (SB‐AdCC) is a subtype of breast AdCC which shows more aggressive clinical behavior than other subtypes. Fine‐needle aspiration (FNA) cytology is a useful diagnostic tool for breast malignancies. However, most of the diagnostic cytological characteristics of AdCC are not present in SB‐AdCC and cytomorphological studies of this subtype are limited. Here, we evaluated the utility of FNA in the diagnosis of SB‐AdCC of the breast. A search of the pathology archives of our institutions for FNA specimens of histologically confirmed SB‐AdCC between 2012 and 2019 identified four patients with SB‐AdCC of the breast. All patients were female and the average age was 60 years. Cytologically, one case was classified as malignant, two as indeterminate, and one as unsatisfactory. Smears had low to moderate cellularity. All smears showed ribbon‐like material surrounding the clusters and a vertical nuclear arrangement toward the peripheral rim. Hyaline globules appeared only in one case. Cells in all cases showed an oval, angular, and spindle shape hyperchromatic nuclei with mild to severe atypia, and also dispersed naked nuclei similar to the cells of the clusters were detected in one case. In histological sections, these cytological findings were compatible with the histological findings and divergent histological differentiation was detected. Diagnosing of few cellular smears of SB‐AdCC is difficult whereas the features of peripheral rim of the clusters, naked nuclei, and the divergent differentiation may be important for diagnosing SB‐AdCC of the breast. 相似文献
73.
Luigi Yuri Di Marco Costanzo Di Maria Wing-Chiu Tong Michael J. Taggart Stephen C. Robson Philip Langley 《Medical & biological engineering & computing》2014,52(8):707-716
Abdominal uterine electromyograms (uEMG) studies have focused on uterine contractions to describe the evolution of uterine activity and preterm birth (PTB) prediction. Stationary, non-contracting uEMG has not been studied. The aim of the study was to investigate the recurring patterns in stationary uEMG, their relationship with gestation age and PTB, and PTB predictivity. A public database of 300 (38 PTB) three-channel (S1–S3) uEMG recordings of 30 min, collected between 22 and 35 weeks’ gestation, was used. Motion and labour contraction-free intervals in uEMG were identified as 5-min weak-sense stationarity intervals in 268 (34 PTB) recordings. Sample entropy (SampEn), percentage recurrence (PR), percentage determinism (PD), entropy (ER), and maximum length (L MAX) of recurrence were calculated and analysed according to the time to delivery and PTB. Random time series were generated by random shuffle (RS) of actual data. Recurrence was present in actual data (p < 0.001) but not RS. In S3, PR (p < 0.005), PD (p < 0.01), ER (p < 0.005), and L MAX (p < 0.05) were higher, and SampEn lower (p < 0.005) in PTB. Recurrence indices increased (all p < 0.001) and SampEn decreased (p < 0.01) with decreasing time to delivery, suggesting increasingly regular and recurring patterns with gestation progression. All indices predicted PTB with AUC ≥0.62 (p < 0.05). Recurring patterns in stationary non-contracting uEMG were associated with time to delivery but were relatively poor predictors of PTB. 相似文献
74.
75.
Nina V. Vlasenko Yuri N. Kochkin German M. Telbiz Oleksiy V. Shvets Peter E. Strizhak 《RSC advances》2019,9(62):35957
The nature of active acid sites of zeolite H-BEA with different Si/Al ratios (15–407) in liquid phase etherification of isobutylene with ethanol in a continuous flow reactor in the temperature range 80–180 °C has been explored. We describe and discuss data concerning the strength and concentration of acid sites of H-BEA obtained by techniques of stepwise (quasi-equilibrium) thermal desorption of ammonia, X-ray diffraction, low-temperature adsorption of nitrogen, FTIR spectroscopy of adsorbed pyridine and solid-state 27Al MAS NMR. The average values of the adsorption energy of NH3 on H-BEA were experimentally determined as 63.7; 91.3 and 121.9 mmol g−1 (weak, medium, and strong, respectively). In agreement with this, a correlation between the rate of ethyl-tert-butyl ether synthesis and the concentration of weak acid sites (ENH3 = 61.6–68.9 kJ mol−1) has been observed. It was concluded that the active sites of H-BEA for this reaction are Brønsted hydroxyls representing internal silanol groups associated with octahedrally coordinated aluminum in the second coordination sphere.The active sites of H-BEA zeolites for ETBE synthesis are the weak Brønsted acid sites representing internal silanol groups. 相似文献
76.
Tomoro Hishiki Hiroshi Horie Yasuyuki Higashimoto Katsumi Yotsumoto Shugo Komatsu Yuri Okimoto Harumi Kakuda Yuichi Taneyama Takeshi Saito Keita Terui Tetsuya Mitsunaga Mitsuyuki Nakata Hidemasa Ochiai Moeko Hino Kumiko Ando Hideo Yoshida Jun Iwai 《Pediatric surgery international》2014,30(9):919-926
Purpose
In the recent years in Japan, an increasing number of patients with neuroblastoma (NB) are being treated by the “delayed local treatment (DL)” policy, undergoing surgery after the completion of high-dose chemotherapy with hematopoietic stem cell rescue (HDC). We reviewed the histopathological findings of second-look operations, including those of patients treated with DL.Patients
From 1998 to 2013, 26 patients with high-risk NB underwent radical operation following chemotherapy. Surgery was performed after induction chemotherapy in 17 cases (standard; STD), whereas 9 cases completed induction chemotherapy and HDC before undergoing tumor resection (DL). The amount of necrosis and the degree of differentiation within the post-treatment tumor were assessed.Results
Eighty-eight percent of the tumors showed necrosis in more than 1/3 of the specimen. Two DL cases showed complete disappearance of viable tumor cells. Amount of necrosis did not affect the prognosis of the patient. Tumors with immature, poorly differentiated phenotypes showed an extremely aggressive thereafter. Though not statistically proven, 123I-MIBG (metaiodobenzylguanidine) uptake may be correlated with the amount of viable cells remaining within the tumor, but not with the degree of differentiation.Conclusions
Our results support the previous reports advocating that tumors that sustain unfavorable histology after chemotherapy behave aggressively thereafter. 相似文献77.
Rabea Alhosh Yuri Genyk Sophoclis Alexopoulos Daniel Thomas Shengmei Zhou George Yanni Nanda Kerkar 《Pediatric transplantation》2014,18(5):E157-E160
HPS is a significant complication of portal hypertension in children with chronic liver disease and is an established indication for LT. It is characterized clinically by the triad of pulmonary vascular dilatation causing hypoxemia in the setting of advanced liver disease. NRH, a cause of non‐cirrhotic portal hypertension, is characterized by diffuse benign transformation of the hepatic parenchyma into small regenerative nodules with minimal or no fibrosis. Development of NRH and HPS in pediatric LT recipients has not been reported, although occasional cases have been reported in adult LT recipients. In this report, we discuss a case of a three‐yr‐old male who developed HPS, two yr after LT. Pulmonary and cardiac causes for hypoxemia were ruled out by appropriate investigations including a chest X ray, echocardiogram, cardiac catheterization, and a CT angiographic study. The diagnosis of HPS was confirmed via bubble echocardiogram that demonstrated intrapulmonary shunting. Open liver biopsy revealed marked NRH. The patient underwent liver retransplantation that resulted in complete reversal of his pulmonary symptoms and normal oxygen saturations within three months after LT. 相似文献
78.
79.
Yuri Geinisman Leyla Detoledo-Morrell Frank Morrell Inna S. Persina Michael A. Beatty 《The Journal of comparative neurology》1996,368(3):413-423
Synapses in the middle molecular layer of the rat dentate gyrus were analyzed by electron microscopy during the maintenance phase of long-term potentiation (LTP). LTP was induced by high-frequency stimulation of the medial perforant path carried out on each of 4 consecutive days. The dentate gyrus was examined electron microscopically 13 days following the fourth stimulation. At this time point, synaptic responses were still significantly enhanced relative to baseline, although the extent of their potentiation was lower than 1 hour after the last high-frequency stimulation. Stimulated, but not potentiated, rats served as controls. Using the stereological double disector method, estimates of the number of different morphological types of synapses per postsynaptic neuron were obtained. The number of asymmetrical axodendritic synapses increased (by 28%) during LTP maintenance, whereas the number of other synaptic types was not significantly altered. Our previous work demonstrated that the induction of LTP is followed by a selective increase in the number of axospinous perforated synapses with multiple, completely partitioned, transmission zones. Thus, the induction and maintenance phases of LTP are characterized by different structural synaptic alterations. These alterations may be related to each other as indicated by another finding of the present study regarding the existence of perforated synapses that appear to be transitional between axospinous and axodendritic junctions. This suggests a model of structural synaptic plasticity associated with LTP in which some axospinous perforated synapses increase in numbers shortly after the induction of LTP and are then converted into axodendritic ones during LTP maintenance. © 1996 Wiley-Liss, Inc. 相似文献
80.
Elina Bondareva Yuri Dekhtyar Vladislavs Gorosko Hermanis Sorokins Alexander Rapoport 《Materials》2022,15(1)
The ability of cells to adhere to substrates is an important factor for the effectiveness of biotechnologies and bioimplants. This research demonstrates that the statistical distribution of the sizes of the cells (Saccharomyces cerevisiae) attached to the substrate surface correlates with the statistical distribution of electrical potential on the substrate’s surface. Hypothetically, this behavior should be taken into consideration during the processing of surfaces when cell adhesion based on cell size is required. 相似文献