全文获取类型
收费全文 | 19309篇 |
免费 | 2026篇 |
国内免费 | 481篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 252篇 |
妇产科学 | 352篇 |
基础医学 | 2379篇 |
口腔科学 | 189篇 |
临床医学 | 2363篇 |
内科学 | 3459篇 |
皮肤病学 | 242篇 |
神经病学 | 3643篇 |
特种医学 | 679篇 |
外国民族医学 | 4篇 |
外科学 | 964篇 |
综合类 | 1925篇 |
预防医学 | 1082篇 |
眼科学 | 249篇 |
药学 | 1381篇 |
5篇 | |
中国医学 | 357篇 |
肿瘤学 | 2235篇 |
出版年
2024年 | 23篇 |
2023年 | 303篇 |
2022年 | 327篇 |
2021年 | 662篇 |
2020年 | 744篇 |
2019年 | 772篇 |
2018年 | 708篇 |
2017年 | 822篇 |
2016年 | 755篇 |
2015年 | 767篇 |
2014年 | 1075篇 |
2013年 | 1563篇 |
2012年 | 981篇 |
2011年 | 1057篇 |
2010年 | 859篇 |
2009年 | 912篇 |
2008年 | 893篇 |
2007年 | 952篇 |
2006年 | 796篇 |
2005年 | 760篇 |
2004年 | 660篇 |
2003年 | 634篇 |
2002年 | 500篇 |
2001年 | 482篇 |
2000年 | 384篇 |
1999年 | 329篇 |
1998年 | 338篇 |
1997年 | 291篇 |
1996年 | 280篇 |
1995年 | 283篇 |
1994年 | 215篇 |
1993年 | 178篇 |
1992年 | 165篇 |
1991年 | 140篇 |
1990年 | 127篇 |
1989年 | 115篇 |
1988年 | 93篇 |
1987年 | 95篇 |
1986年 | 95篇 |
1985年 | 124篇 |
1984年 | 120篇 |
1983年 | 83篇 |
1982年 | 83篇 |
1981年 | 76篇 |
1980年 | 75篇 |
1979年 | 41篇 |
1978年 | 23篇 |
1977年 | 14篇 |
1976年 | 16篇 |
1975年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
91.
92.
It is shown that a repetitive pulse sequence consisting of two 90° pulses and gradients in a 1:2 ratio around the second 90° pulse generates interscan shifted stimulated echoes (SSTEs) and intrascan multiple spin echoes (MSEs). Separation of these two types of signals is accomplished using specific gradient crusher schemes. The intensity of the SSTEs is an order of magnitude larger than that of the MSEs and determines the signal contrast if both effects are selected simultaneously. The SSTE sequence generates improved contrast between gray and white matter, even at high field, which is explained in terms of increased inverse T1-weighting for the interscan echo. The MSE image has low signal to noise and no detectable contrast. The effect of interscan diffusion weighting is also discussed. 相似文献
93.
Cohen syndrome: fertility in a female patient 总被引:1,自引:0,他引:1
In this report we describe fertility in an adult female with Cohen syndrome. She gave birth to a son, now 1.5 years old, with discrete facial stigmata and slight psychomotor retardation. 相似文献
94.
目的观察耐药乳腺癌细胞c-myc表达及其反义寡核苷酸对耐药的逆转效应,探讨c-myc在耐药调控中的作用。方法运用流式细胞仪检测乳腺癌耐药细胞MCF-7/Adr和其药敏亲本系MCF-7的c-myc表达水平。MTT法测定阿霉素作用于上述细胞的药物半数抑制浓度(IC50)。结果MCF-7/Adr耐药细胞c-myc的表达率为70.48%,其亲本药敏细胞系MCF-7c-myc表达率仅46.02%,前者显著高于后者(P<0.05)。阿霉素单独作用于MCF-7/Adr,IC50值为(22.00±1.92)μmol/L,但与4μmol/Lc-myc反义寡核苷酸共孵育后,阿霉素的IC50值则显著下降为(9.60±1.04)μmol/L。结论与其亲本药敏细胞相比较,MCF-7/Adr的c-myc表达显著上调,抑制c-myc的过表达可部分逆转MCF-7/Adr的阿霉素抵抗,提示c-myc参与肿瘤耐药的发生。 相似文献
95.
Data from studies of rankings of acceptability and severity of various disabilities were converted to a common metric of percentile equivalent ranks. A total of 1331 data points from 53 studies yielded the following overall percentile equivalent ranks for 24 disabilities: diabetes (most acceptable), ulcer, arthritis, asthma, heart condition, speech problems, crippled, orthopedic disability, physical disability, amputation, emotional disturbance, appearance disability, deafness, learning disability, stroke, cancer, paraplegia, blindness, epilepsy, tuberculosis, cerebral palsy, mental retardation, mental illness, and multiple disabilities (least acceptable). Rankings of the severity of seven disabilities yielded a somewhat different order that correlated 0.55 with the total data. Rankings of a mild disability were, on average, 40 percentile points higher than rankings for the same disability labeled severe or profound. 相似文献
96.
Kirk J. Schneider 《Clinical psychology》2002,9(1):26-27
I contend that although the Luborsky et al. findings on the Dodo bird verdict are noteworthy, the methodology on which they are based is significantly delimited. Amplifying Luborsky et al.'s moderate recognition of that delimitation, I propose a qualitative complement to the extant research. I call this complement "amalgamated" qualitative research and propose that it will deepen, clarify, and contextualize Luborsky et al.'s enigmatic findings. Until this amalgam is implemented, therapy research will be relegated to impressions rather than fine-grained illuminations. 相似文献
97.
SOSHU SATO NOBUO SHINOHARA SHIN SUZUKI TORU HARABAYASHI TOMOHIKO KOYANAGI 《International journal of urology》2004,11(5):269-275
AIM: To evaluate the incidence, nature and prognosis of multiple primary malignancies involving renal cell carcinoma (RCC) in Japan. METHODS: Between 1975 and 1998, 319 patients underwent an operation for RCC at Hokkaido University, Sapporo, Japan. The incidence of other primary malignancies was determined and classified as antecedent, synchronous or subsequent. Follow-up was obtained by thorough chart review or telephone interview, and ranged from 0 to 276 months (median 49.0 months). To analyze the influence of other primary malignancies on prognosis, overall and cause-specific survival rates of the patients with an antecedent or synchronous malignancy were compared to the remaining patients. RESULTS: Of the 319 patients there was at least one other malignancy in 38 patients (12%). Four patients had two other malignancies. The other malignancies were antecedent in 13, synchronous in 19 and subsequent in 10 patients. Twenty-two patients had gastrointestinal cancer. In cases of antecedent or synchronous diagnosis of other primary malignancies, RCC was commonly incidental, small or low-stage. Multivariate analysis using Cox's proportional hazards model showed that, for overall survival, the presence of other antecedent or synchronous malignancies was the second most significant prognostic factor, following the pathological stage of RCC. CONCLUSIONS: In Japanese patients with RCC, the incidence of other primary malignancies was not uncommon and these malignancies contributed to the prognosis of these patients. Therefore, the malignant potential of individual tumors should be paid careful attention in the management of these patients. 相似文献
98.
A. Compston 《Acta neurologica Scandinavica》2006,113(S183):41-47
Contemporary licensed treatments for multiple sclerosis fail to provide a solution for the disease because their effects are limited to a modest reduction in the frequency of new episodes. They do not reduce disability or materially influence the progressive phase of the disease. A contemporary strategy for management requires a more detailed analysis of the separate contributions to the clinical features and overall course made by inflammation, axonal injury, compensatory mechanisms, and remyelination. From this formulation emerges the need either for early and fully effective suppression of the inflammatory response, limiting the damage to all components of the axon-glial unit; or the development of strategies for axonal and myelin repair that solve the issues of controlled differentiation, delivery and timing of these cell and growth factor-based interventions. 相似文献
99.
本文运用二值回归判别法探讨了胆汁中4种初级结合型胆汁酸含量变化对胆汁成石性的判断价值。根据52例测试数据得出4因素二类判别函数:Y=0.0395X_1-0.0386X_2 0.0185X_3 O.0586X_4-1.0513。87例自、回代结果表明,该判别函数在判断符合率、错误率、假阳性率、假阴性率等诸方面均较使用1种初级结合型胆汁酸作为判别指标优越。 相似文献
100.
J. M. Ladero R. Arroyo C. De Andrés F. J. Jiménez-Jiménez J. A. Molina E. Varela de Seijas S. Giménez-Roldán J. Benítez 《Acta neurologica Scandinavica》1994,89(2):102-104
To elucidate whether any relationship exists between genetic polymorphic acetylation and the risk for multiple sclerosis (MS), we determined this polymorphism, using sulphamethazine, in 71 patients with definite MS and in 268 age-matched controls. Thirty-seven patients (52.1%) and 151 controls (56.3%) were classified as slow acetylators (not significant difference). No relation was found between acetylator polymorphism and age at onset of disease in MS patient's group. Our results do not support the existence of any relationship between acetylator polymorphism and the risk for MS. 相似文献