全文获取类型
收费全文 | 20032篇 |
免费 | 1184篇 |
国内免费 | 141篇 |
专业分类
耳鼻咽喉 | 175篇 |
儿科学 | 509篇 |
妇产科学 | 377篇 |
基础医学 | 2340篇 |
口腔科学 | 760篇 |
临床医学 | 1943篇 |
内科学 | 4268篇 |
皮肤病学 | 418篇 |
神经病学 | 1218篇 |
特种医学 | 466篇 |
外国民族医学 | 6篇 |
外科学 | 2561篇 |
综合类 | 520篇 |
一般理论 | 15篇 |
预防医学 | 1647篇 |
眼科学 | 806篇 |
药学 | 1898篇 |
中国医学 | 218篇 |
肿瘤学 | 1212篇 |
出版年
2024年 | 31篇 |
2023年 | 262篇 |
2022年 | 723篇 |
2021年 | 1139篇 |
2020年 | 740篇 |
2019年 | 896篇 |
2018年 | 1054篇 |
2017年 | 746篇 |
2016年 | 818篇 |
2015年 | 822篇 |
2014年 | 1114篇 |
2013年 | 1300篇 |
2012年 | 1779篇 |
2011年 | 1814篇 |
2010年 | 1065篇 |
2009年 | 806篇 |
2008年 | 1193篇 |
2007年 | 1074篇 |
2006年 | 908篇 |
2005年 | 758篇 |
2004年 | 624篇 |
2003年 | 504篇 |
2002年 | 451篇 |
2001年 | 55篇 |
2000年 | 63篇 |
1999年 | 62篇 |
1998年 | 58篇 |
1997年 | 49篇 |
1996年 | 46篇 |
1995年 | 36篇 |
1994年 | 22篇 |
1993年 | 39篇 |
1992年 | 26篇 |
1991年 | 18篇 |
1990年 | 20篇 |
1989年 | 24篇 |
1988年 | 19篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 19篇 |
1983年 | 19篇 |
1982年 | 16篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1974年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
61.
62.
63.
Anusha Paritala Brijesh Takkar Nripen Gaur Deepak Soni Mohammad Hasnat Ali Anubha Rathi 《Indian journal of ophthalmology》2022,70(3):914
Purpose:The proportion of axial length (AL) occupied by vitreous chamber depth (VCD), or VCD:AL, consistently correlates to ocular biometry in the general population. Relation of VCD:AL to ocular biometry in high myopia is not known. The purpose of this study is to evaluate the relation of VCD and VCD:AL to ocular biometry of highly myopic eyes.Methods:This was a cross-sectional retrospective study of records of 214 myopic eyes (<−1 D SE, aged 20–40 years) attending the refractive surgery services. High axial myopia was defined as AL >26.5 mm. Eyes with posterior staphyloma and myopic maculopathy were excluded. Records were assessed for measurements of AL, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), white to white diameter (WTW), and vitreous chamber depth (VCD). Groups were formed based on increasing AL, while the sum of CCT, ACD, and LT was recorded as anterior segment depth (AS). The main outcome measure was the correlation of VCD and VCD:AL to ocular biometry. A comparison was also performed based on of degree of axial myopia.Results:Mean age of the patients was 27.0 ± 5.2 years. VCD showed a very strong correlation with AL (R = 0.98, P < 0.001) but did not correlate to any anterior parameter. VCD:AL showed moderate negative relation with AS (R = −0.43, P < 0.001) and ACD (R = −0.3, P < 0.001), while it had a weakly negative relation with LT (R = −0.18, P = 0.006). VCD:AL showed strong negative relation (R > ~0.7) with AS in all individual groups of AL. Among anterior parameters, WTW showed the most consistent relation with ocular biometry.Conclusion:VCD:AL is a better correlate of ocular biometry in high myopia as compared to VCD. However, the correlation is weaker than that noted by previous studies done on the general population. Longitudinal studies of VCD:AL in the younger age group is recommended. 相似文献
64.
Zuhier A. Awan Shareefa A. AlGhamdi Nabil A. Alhakamy Solomon Z. Okbazghi Mohamed A. Alfaleh Shaimaa M. Badr-Eldin Hibah M. Aldawsari Mohammed A. S. Abourehab Hani Z. Asfour Shadi A. Zakai Mohammad W. Alrabia Aya A. Negm Mohamed A. El-Moselhy Sara S. Sharkawi Waleed Y. Rizg 《Drug delivery》2022,29(1):1536
Certain anticancer agents selectively target the nucleus of cancer cells. One such drug is 2-methoxyestradiol (2ME), which is used for treating lung cancer. To improve the therapeutic effectiveness of these agents, many new methods have been devised. 2ME was entrapped into the core of hydrophobic invasomes (INVA) covered with Phospholipon 90G and apamin (APA). The Box–Behnken statistical design was implemented to enhance the composition. Using Design-Expert software (Stat-Ease Inc., Minneapolis, MN), the INVA component quantities were optimized to obtain spherical particles with the smallest size, that is, a diameter of 167.8 nm. 2ME-INVA-APA significantly inhibited A549 cells and exhibited IC50 of 1.15 ± 0.04 µg/mL, which is lower than raw 2ME (IC50 5.6 ± 0.2 µg/mL). Post 2ME-INVA-APA administration, a significant rise in cell death and necrosis was seen among the A549 cells compared to those treated with plain formula or 2ME alone. This effect was indicated by increased Bax expression and reduced Bcl-2 expression, as well as mitochondrial membrane potential loss. Moreover, the cell cycle analysis showed that 2ME-INVA-APA arrests the G2-M phase of the A549 cells. Additionally, it was observed that the micellar formulation of the drug increased the cell count in pre-G1, thereby exhibiting phenomenal apoptotic potential. Furthermore, it up-regulates caspase-9 and p53 and downregulates TNF-α and NF-κβ. Collectively, these findings showed that our optimized 2ME-INVA-APA could easily seep through the cell membrane and induce apoptosis in relatively low doses. 相似文献
65.
Zhang Xu Jung-Hyun Choi David L. Dai Jun Luo Reese Jalal Ladak Qian Li Yimeng Wang Christine Zhang Shane Wiebe Alex C. H. Liu Xiaozhuo Ran Jiaqi Yang Parisa Naeli Aitor Garzia Lele Zhou Niaz Mahmood Qiyun Deng Mohamed Elaish Rongtuan Lin Lara K. Mahal Tom C. Hobman Jerry Pelletier Tommy Alain Silvia M. Vidal Thomas Duchaine Mohammad T. Mazhab-Jafari Xiaojuan Mao Seyed Mehdi Jafarnejad Nahum Sonenberg 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(32)
66.
Ramy Sadek Mohammad S. Sharawi Charles Dubois Hesham Tantawy Jamal Chaouki 《RSC advances》2022,12(35):22608
The chemical reduction process of graphene oxide combined with a mild and controllable thermal treatment under vacuum at 200 °C for 4 hours provided a cost-effective, scalable, and high-yield route for Reduced Graphene Oxide (RGO) industrial production and became a potential candidate for producing electromagnetic interference (EMI) shielding. We investigated graphite, and RGO using l-ascorbic acid and Sodium borohydride before and after thermal treatment by carefully evaluating the chemical and morphological structures. The thermally treated l-ascorbic Acid reduction route (TCRGOL) conductivity was 2.14 × 103 S m−1 and total shielding efficiency (SET) based on mass loadings per area of shielding was 94 dB with about one-tenth less graphite weight and surpassing other graphene reduction mechanisms in the frequency range of 8.2–12.4 GHz, i.e., X-band, at room temperature while being tested using the waveguide line technique. The developed treatment represents valuable progress in the path to chemical reduction using a safe reducing agent and offering superior quality RGO rarely achieved with the top-down technique, providing a high EMI shielding performance.The developed two-step protocol offers a superior reduced graphene oxide TCRGOL quality (7 layers), and its SET was 94 dB over the X-band. 相似文献
67.
Alfredo Oliveros Ki Hyun Yoo Mohammad Abdur Rashid Ana Corujo-Ramirez Benjamin Hur Jaeyun Sung Yuanhang Liu John R. Hawse Doo-Sup Choi Detlev Boison Mi-Hyeon Jang 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(28)
Chemotherapy-induced cognitive impairment (CICI) has emerged as a significant medical problem without therapeutic options. Using the platinum-based chemotherapy cisplatin to model CICI, we revealed robust elevations in the adenosine A2A receptor (A2AR) and its downstream effectors, cAMP and CREB, by cisplatin in the adult mouse hippocampus, a critical brain structure for learning and memory. Notably, A2AR inhibition by the Food and Drug Administration–approved A2AR antagonist KW-6002 prevented cisplatin-induced impairments in neural progenitor proliferation and dendrite morphogenesis of adult-born neurons, while improving memory and anxiety-like behavior, without affecting tumor growth or cisplatin’s antitumor activity. Collectively, our study identifies A2AR signaling as a key pathway that can be therapeutically targeted to prevent cisplatin-induced cognitive impairments. 相似文献
68.
Zahra Davoudi Mohammad Hallajnejad Elena Jamali Mohammadjavad Honarvar 《Clinical Case Reports》2022,10(7)
Refractory aggressive prolactinomas are detected after the unresponsiveness to conventional therapies. We report two cases that underwent temozolomide treatment and have been in near‐complete remission ever since. We suggest the pathology techniques for earlier detection and, subsequently, treatment with temozolomide to reduce morbidities and better respond to therapy. 相似文献
69.
Natago Guil Mbodj Mohammad Abuabiah Peter Plapper Maxime El Kandaoui Slah Yaacoubi 《Materials》2022,15(13)
Laser Wire Additive Manufacturing (LWAM) is a flexible and fast manufacturing method used to produce variants of high metal geometric complexity. In this work, a physics-based model of the bead geometry including process parameters and material properties was developed for the LWAM process of large-scale products. The developed model aimed to include critical process parameters, material properties and thermal history to describe the relationship between the layer height with different process inputs (i.e., the power, the standoff distance, the temperature, the wire-feed rate, and the travel speed). Then, a Model Predictive Controller (MPC) was designed to keep the layer height trajectory constant taking into consideration the constraints faced in the LWAM technology. Experimental validation results were performed to check the accuracy of the proposed model and the results revealed that the developed model matches the experimental data. Finally, the designed MPC controller was able to track a predefined layer height reference signal by controlling the temperature input of the system. 相似文献
70.
Sarang Younesi Bahareh Yazdani Mohammad Mahdi Taheri Amin Pourandokht Saadati Soudabeh Jamali MohammadHossein Modarresi Shahram Savad Saloomeh Amidi Homayoun Razavi Soudeh GhafouriFard 《Journal of clinical laboratory analysis》2022,36(7)
BackgroundNowadays, neonatal screening has become an essential part of routine newborn care in the world. This is a non‐invasive evaluation that evaluated inborn errors of metabolisms (IEMs) using tandem mass spectrometry (LC‐MS/MS) for the evaluation of the baby''s risk of certain metabolic disorders.MethodsThis retrospective study was conducted on 39987 Iranian newborns who were referred to Nilou Medical Laboratory, Tehran, Iran, for newborn screening programs of IEMs. We incorporated second‐tier tests and secondary biomarkers to improve positive predictive value (PPV).ResultsStatistical data were recorded via call interviewing in 6–8 months after their screening tests. The overall prevalence of IEM was 1:975. The mean age of all participants was 3.9 ± 1.1 days; 5.1% of participants were over 13 days and 7.7% were preterm or underweight. A total of 11384 (29.4%) of the cases were born in a consanguineous family. The type of delivery was the cesarean section in 8332 (51.3%) valid cases. The neonatal screening results had an overall negative predictive value (NPV) of 100% and the overall PPV of 40.2%. The false‐positive rate was 0.15%.ConclusionThis study showed a high incidence of metabolic disease due to a high rate of consanguineous marriages in Iran and indicated that incorporation of second‐tier tests and secondary biomarkers improves PPV of neonatal screening programs. 相似文献