全文获取类型
收费全文 | 11969篇 |
免费 | 547篇 |
国内免费 | 99篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 293篇 |
妇产科学 | 160篇 |
基础医学 | 1481篇 |
口腔科学 | 177篇 |
临床医学 | 625篇 |
内科学 | 3166篇 |
皮肤病学 | 462篇 |
神经病学 | 855篇 |
特种医学 | 756篇 |
外科学 | 2324篇 |
综合类 | 53篇 |
一般理论 | 2篇 |
预防医学 | 218篇 |
眼科学 | 173篇 |
药学 | 572篇 |
中国医学 | 22篇 |
肿瘤学 | 1210篇 |
出版年
2023年 | 57篇 |
2022年 | 118篇 |
2021年 | 242篇 |
2020年 | 165篇 |
2019年 | 180篇 |
2018年 | 236篇 |
2017年 | 224篇 |
2016年 | 295篇 |
2015年 | 296篇 |
2014年 | 411篇 |
2013年 | 483篇 |
2012年 | 668篇 |
2011年 | 776篇 |
2010年 | 508篇 |
2009年 | 440篇 |
2008年 | 772篇 |
2007年 | 796篇 |
2006年 | 805篇 |
2005年 | 812篇 |
2004年 | 743篇 |
2003年 | 712篇 |
2002年 | 785篇 |
2001年 | 112篇 |
2000年 | 89篇 |
1999年 | 147篇 |
1998年 | 217篇 |
1997年 | 167篇 |
1996年 | 187篇 |
1995年 | 156篇 |
1994年 | 124篇 |
1993年 | 114篇 |
1992年 | 89篇 |
1991年 | 79篇 |
1990年 | 82篇 |
1989年 | 62篇 |
1988年 | 51篇 |
1987年 | 44篇 |
1986年 | 39篇 |
1985年 | 33篇 |
1984年 | 42篇 |
1983年 | 26篇 |
1982年 | 31篇 |
1981年 | 37篇 |
1980年 | 37篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1973年 | 7篇 |
1971年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Wang L Kuroiwa Y Kamitani T Li M Takahashi T Suzuki Y Shimamura M Hasegawa O 《Journal of neurology》2000,247(5):356-363
To determine whether there are characteristic changes in event-related potentials (ERPs) in parkinsonian syndromes we studied
8 patients with progressive supranuclear palsy (PSP), 10 patients with corticobasal degeneration (CBD), 9 patients with striatonigral
degeneration (SND), and 16 patients with idiopathic Parkinson's disease (PD) with a mean duration of illness shorter than
5 years in each group. A visual oddball paradigm was employed to elicit P300. P300 to the rare target and rare nontarget stimuli
and reaction time (RT) to rare target stimuli in each group were compared with those in the corresponding age-matched normal
control group and to each other after age correction. The correlation of P300 and RT to motor disability score was also studied.
In PSP P300 amplitude was markedly reduced while in CBD P300 latency was prolonged. P300 amplitude to rare nontargets in SND
and PD was attenuated. The mean RT in the PSP and the CBD group was significantly longer than in the other two groups. The
mean RT in PD and P300 amplitude to rare nontargets in both CBD and PD showed significant correlation with the severity of
motor disability. Simultaneous measurement of P300 and RT may yield useful supplementary information in facilitating diagnosis
of parkinsonian syndromes in addition to clinical criteria.
Received: 6 April 1999, Received in revised form: 5 August 1999, Accepted: 12 January 2000 相似文献
82.
Takeo Shimo Naoki Ashizawa Koji Matsumoto Takashi Nakazawa Osamu Nagata 《Toxicological sciences》2005,87(1):267-276
The possible mechanism of the underlying nephropathy found in the rat toxicity study of FYX-051, a xanthine oxidoreductase inhibitor, was investigated. Rats received oral treatment of either 1 or 3 mg/kg of FYX-051, with and without citrate for four weeks to elucidate whether nephropathy could be caused by materials deposited in the kidney. Furthermore, analysis of the renal deposits in rats was also performed. Consequently, interstitial nephritis comprising interstitial inflammatory cell infiltration, dilatation, basophilia and epithelial necrosis of renal tubules and collecting ducts, deposits in renal tubules and collecting ducts, and so forth was seen in six of the eight rats and in all eight rats in the 1 and 3 mg/kg FYX-051 alone groups, respectively, with the intensity in the 3 mg/kg group being moderate to severe. In the simultaneous treatment with citrate group, however, no alterations were observed in the kidney, except for minimal interstitial nephritis in one instance in the 3 mg/kg FYX-051 + citrate group along with an increased urinary pH, leading to an increase in xanthine solubility. Analysis of intrarenal deposits showed that the entity would be composed of xanthine crystals. The present study, therefore, showed that nephropathy in rats occurring after the administration of FYX-051 was a secondary change caused by xanthine crystals being deposited in the kidney, and no other causes could be implicated in this kidney lesion. 相似文献
83.
Colocalization of the tetraspanins, CO-029 and CD151, with integrins in human pancreatic adenocarcinoma: impact on cell motility. 总被引:6,自引:0,他引:6
Sabine Gesierich Claudia Paret Dagmar Hildebrand Jürgen Weitz Kaspar Zgraggen Friedrich H Schmitz-Winnenthal Vaclav Horejsi Osamu Yoshie Dorothee Herlyn Leonie K Ashman Margot Z?ller 《Clinical cancer research》2005,11(8):2840-2852
PURPOSE: Patients with pancreatic adenocarcinoma have a poor prognosis due to the extraordinary high invasive capacity of this tumor. Altered integrin and tetraspanin expression is suggested to be an important factor. We recently reported that after protein kinase C activation, colocalization of alpha6beta4 with the tetraspanin CO-029 strongly supports migration of a rat pancreatic adenocarcinoma. The finding led us to explore whether and which integrin-tetraspanin complexes influence the motility of human pancreatic tumors. EXPERIMENTAL DESIGN: Integrin and tetraspanin expression of pancreatic and colorectal adenocarcinoma was evaluated with emphasis on colocalization and the impact of integrin-tetraspanin associations on tumor cell motility. RESULTS: The majority of pancreatic and colorectal tumors expressed the alpha2, alpha3, alpha6, beta1, and beta4 integrins and the tetraspanins CD9, CD63, CD81, CD151, and CO-029. Expression of alpha6beta4 and CO-029 was restricted to tumor cells, whereas alpha1, alpha2, alpha3, alpha6, beta1, and CD9, CD81, CD151 were also expressed by the surrounding stroma. CD63, CD81, and beta1 expression was observed at comparably high levels in healthy pancreatic tissue. alpha3beta1 frequently colocalized and coimmunoprecipitated with CD9, CD81, and CD151, whereas alpha6beta4 colocalized and coimmunoprecipitated mostly with CD151 and CO-029. Notably, protein kinase C activation strengthened only the colocalization of CD151 and CO-029 with beta4 and was accompanied by internalization of the integrin-tetraspanin complex, decreased laminin 5 adhesion, and increased cell migration. CONCLUSION: alpha6beta4 is selectively up-regulated in pancreatic and colorectal cancer. The association of alpha6beta4 with CD151 and CO-029 correlates with increased tumor cell motility. 相似文献
84.
85.
Koichi Ito Emiko Chiba Noriko Oyama-Manabe Satoshi Washino Osamu Manabe Tomoaki Miyagawa Kohei Hamamoto Masahiro Hiruta Keisuke Tanno Hiroshi Shinmoto 《Magnetic resonance in medical sciences》2022,21(3):477
Purpose: To assess the diagnostic performance of the tumor contact length (TCL) and apparent diffusion coefficient (ADC) for predicting extraprostatic extension (EPE) of prostate cancer with capsular abutment (CA).Methods: Ninety-three patients with biopsy-proven prostate cancer underwent 3-Tesla MRI, including diffusion-weighted imaging (b value = 0, 2000 s/mm2) and radical prostatectomy. Two experienced radiologists, blinded to the clinicopathological data, retrospectively assessed the presence of CA on T2-weighted imaging (T2WI). TCL on T2WI and ADC values were measured on detecting CA in prostate cancer. We used the receiver operating characteristic curves to assess the diagnostic performance of TCL and ADC values for predicting EPE.Results: CA was present in 58 prostate cancers among 93 patients. The cut-off value for TCL was 6.9 mm, which yielded an area under the curve (AUC) of 0.75. This corresponded to a sensitivity, specificity, and accuracy of 84.2%, 61.5%, and 69.0%, respectively. The cut-off value for ADC was 0.63 × 10–3 mm2/s, which yielded an AUC of 0.76. This, in turn, corresponded to a sensitivity, specificity, and accuracy of 84.2%, 59.0%, and 67.2%, respectively. The combined cut-off value of TCL and ADC yielded an AUC of 0.82. The specificity (84.6%) and accuracy (81.0%) of the combined value were superior to their individual values (P < 0.05).Conclusion: A combination of TCL and ADC values provided high specificity and accuracy for detecting EPE of prostatic cancer with CA. 相似文献
86.
Cetuximab delivery and antitumor effects are enhanced by mild hyperthermia in a xenograft mouse model of pancreatic cancer 下载免费PDF全文
Ryoichi Miyamoto Tatsuya Oda Shinji Hashimoto Tomohiro Kurokawa Yuki Inagaki Osamu Shimomura Yusuke Ohara Keiichi Yamada Yoshimasa Akashi Tsuyoshi Enomoto Mikio Kishimoto Hideto Yanagihara Eiji Kita Nobuhiro Ohkohchi 《Cancer science》2016,107(4):514-520
Even with current promising antitumor antibodies, their antitumor effects on stroma‐rich solid cancers have been insufficient. We used mild hyperthermia with the intent of improving drug delivery by breaking the stromal barrier. Here, we provide preclinical evidence of cetuximab + mild hyperthermia therapy. We used four in vivo pancreatic cancer xenograft mouse models with different stroma amounts (scarce, MIAPaCa‐2; moderate, BxPC‐3; and abundant, Capan‐1 and Ope‐xeno). Cetuximab (1 mg/kg) was given systemically, and the mouse leg tumors were concurrently heated using a water bath method for 30 min at three different temperatures, 25°C (control), 37°C (intra‐abdominal organ level), or 41°C (mild hyperthermia) (n = 4, each group). The evaluated variables were the antitumor effects, represented by tumor volume, and in vivo cetuximab accumulation, indirectly quantified by the immunohistochemical fluorescence intensity value/cell using antibodies against human IgG Fc. At 25°C, the antitumor effects were sufficient, with a cetuximab accumulation value (florescence intensity/cell) of 1632, in the MIAPaCa‐2 model, moderate (1063) in the BxPC‐3 model, and negative in the Capan‐1 and Ope‐xeno models (760, 461). By applying 37°C or 41°C heat, antitumor effects were enhanced shown in decreased tumor volumes. These enhanced effects were accompanied by boosted cetuximab accumulation, which increased by 2.8‐fold (2980, 3015) in the BxPC‐3 model, 2.5‐ or 4.8‐fold (1881, 3615) in the Capan‐1 model, and 3.2‐ or 4.2‐fold (1469, 1922) in the Ope‐xeno model, respectively. Cetuximab was effective in treating even stroma‐rich and k‐ras mutant pancreatic cancer mouse models when the drug delivery was improved by combination with mild hyperthermia. 相似文献
87.
Matsuura T Takehara Y Kaijima H Teramoto S Kato O 《Journal of assisted reproduction and genetics》2008,25(4):163-167
Purpose Although many reports support stimulated in vitro fertilization, several patients do not respond to it well. Furthermore,
stimulated treatment could be associated with reduced ovarian response. We describe three successful cases involving patients
of advanced age from whom dominant follicles were retrieved during the natural cycle.
Materials and methods All patients had failed to bear children through stimulated in vitro fertilization. In case 1, a follicle was retrieved after
a gonadotropin-releasing hormone agonist was used to induce luteinizing hormone surge. In cases 2 and 3, pregnancy was achieved
via completely natural cycles.
Results One embryo was transferred every 16 cycles. Ongoing pregnancy—defined as pregnancy progressing beyond gestation week 9—was
established in three cycles. The patients successfully delivered and had uneventful neonatal courses.
Conclusion Mature oocyte retrieval followed by natural rather than stimulated in vitro fertilization might be a potential treatment for
patients of advanced age when stimulated in vitro fertilization has been repeatedly unsuccessful.
Capsule We describe three successful pregnancies and deliveries achieved via natural IVF cycles: the patients were older than 37 years
with repeated failures by stimulated IVF. 相似文献
88.
Minimal ovarian stimulation with clomiphene citrate: a large-scale retrospective study 总被引:2,自引:0,他引:2
Enclomiphene, an isomeric component of clomiphene citrate, acts antagonistically to the oestradiol receptor at the hypothalamus level, inhibiting both negative and positive feedback, and resulting in the induction of ovarian stimulation and suppression of ovulation. The minimal ovarian stimulation protocol takes full advantage of these characteristics of clomiphene citrate. Administration of 50 mg clomiphene citrate is initiated on cycle day 3, and from day 8 patients receive 150 IU of FSH every other day. When the size of the dominant follicle and the oestradiol concentration reach the predefined values, gonadotrophin-releasing hormone agonist is administered to induce follicular maturation. Oocytes are then retrieved 32-35 h later. Because the short half-life of enclomiphene (24 h) is of critical importance in this protocol, it is necessary to continue oral administration of clomiphene citrate until the day before maturation is triggered. Of all 43,433 cycles initiated, the rates for oocyte retrieval and embryo cleavage were 83 and 64% respectively. The mean number of oocytes retrieved was 2.2. The rates for live births, miscarriages, and ectopic pregnancies, in relation to initiated cycles, including cases of frozen-thawed transfer, were 11.1, 3.4 and 0.2% respectively. 相似文献
89.
Akira Kunimatsu Koichiro Yasaka Hiroyuki Akai Haruto Sugawara Natsuko Kunimatsu Osamu Abe 《Magnetic resonance in medical sciences》2022,21(1):95
Texture analysis, as well as its broader category radiomics, describes a variety of techniques for image analysis that quantify the variation in surface intensity or patterns, including some that are imperceptible to the human visual system. Cerebral gliomas have been most rigorously studied in brain tumors using MR-based texture analysis (MRTA) to determine the correlation of various clinical measures with MRTA features. Promising results in cerebral gliomas have been shown in the previous MRTA studies in terms of the correlation with the World Health Organization grades, risk stratification in gliomas, and the differentiation of gliomas from other brain tumors. Multiple MRTA studies in gliomas have repeatedly shown high performance of entropy, a measure of the randomness in image intensity values, of either histogram- or gray-level co-occurrence matrix parameters. Similarly, researchers have applied MRTA to other brain tumors, including meningiomas and pediatric posterior fossa tumors.However, the value of MRTA in the clinical use remains undetermined, probably because previous studies have shown only limited reproducibility of the result in the real world. The low-to-modest generalizability may be attributed to variations in MRTA methods, sampling bias that originates from single-institution studies, and overfitting problems to a limited number of samples.To enhance the reliability and reproducibility of MRTA studies, researchers have realized the importance of standardizing methods in the field of radiomics. Another advancement is the recent development of a comprehensive assessment system to ensure the quality of a radiomics study. These two-way approaches will secure the validity of upcoming MRTA studies. The clinical use of texture analysis in brain MRI will be accelerated by these continuous efforts. 相似文献
90.
Masami Goto Osamu Abe Akifumi Hagiwara Shohei Fujita Koji Kamagata Masaaki Hori Shigeki Aoki Takahiro Osada Seiki Konishi Yoshitaka Masutani Hajime Sakamoto Yasuaki Sakano Shinsuke Kyogoku Hiroyuki Daida 《Magnetic resonance in medical sciences》2022,21(1):41
Surface-based morphometry (SBM) is extremely useful for estimating the indices of cortical morphology, such as volume, thickness, area, and gyrification, whereas voxel-based morphometry (VBM) is a typical method of gray matter (GM) volumetry that includes cortex measurement. In cases where SBM is used to estimate cortical morphology, it remains controversial as to whether VBM should be used in addition to estimate GM volume. Therefore, this review has two main goals. First, we summarize the differences between the two methods regarding preprocessing, statistical analysis, and reliability. Second, we review studies that estimate cortical morphological changes using VBM and/or SBM and discuss whether using VBM in conjunction with SBM produces additional values. We found cases in which detection of morphological change in either VBM or SBM was superior, and others that showed equivalent performance between the two methods. Therefore, we concluded that using VBM and SBM together can help researchers and clinicians obtain a better understanding of normal neurobiological processes of the brain. Moreover, the use of both methods may improve the accuracy of the detection of morphological changes when comparing the data of patients and controls.In addition, we introduce two other recent methods as future directions for estimating cortical morphological changes: a multi-modal parcellation method using structural and functional images, and a synthetic segmentation method using multi-contrast images (such as T1- and proton density-weighted images). 相似文献