全文获取类型
收费全文 | 5163篇 |
免费 | 314篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 121篇 |
妇产科学 | 84篇 |
基础医学 | 950篇 |
口腔科学 | 104篇 |
临床医学 | 526篇 |
内科学 | 1058篇 |
皮肤病学 | 185篇 |
神经病学 | 585篇 |
特种医学 | 221篇 |
外国民族医学 | 1篇 |
外科学 | 451篇 |
综合类 | 36篇 |
一般理论 | 3篇 |
预防医学 | 339篇 |
眼科学 | 62篇 |
药学 | 356篇 |
中国医学 | 8篇 |
肿瘤学 | 364篇 |
出版年
2023年 | 27篇 |
2022年 | 53篇 |
2021年 | 118篇 |
2020年 | 73篇 |
2019年 | 83篇 |
2018年 | 91篇 |
2017年 | 79篇 |
2016年 | 99篇 |
2015年 | 175篇 |
2014年 | 184篇 |
2013年 | 212篇 |
2012年 | 374篇 |
2011年 | 426篇 |
2010年 | 236篇 |
2009年 | 215篇 |
2008年 | 391篇 |
2007年 | 422篇 |
2006年 | 338篇 |
2005年 | 385篇 |
2004年 | 322篇 |
2003年 | 326篇 |
2002年 | 283篇 |
2001年 | 39篇 |
2000年 | 26篇 |
1999年 | 46篇 |
1998年 | 71篇 |
1997年 | 57篇 |
1996年 | 42篇 |
1995年 | 41篇 |
1994年 | 34篇 |
1993年 | 24篇 |
1992年 | 21篇 |
1991年 | 20篇 |
1990年 | 16篇 |
1989年 | 8篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1972年 | 3篇 |
排序方式: 共有5496条查询结果,搜索用时 0 毫秒
81.
82.
Bruna de Athayde Casadei Snia T.de O. Lara‐Mendes Camila de Freitas M. Barbosa Christiane Valente Araújo Cristina Almeida de Freitas Vinícius C. Machado Caroline C. Santa‐Rosa 《Australian endodontic journal : the journal of the Australian Society of Endodontology Inc》2020,46(1):101-106
Procedural accidents are eventualities that may occur during endodontic treatment because of lack of attention to detail or even unforeseeable situations. Knowledge of the root canal anatomy and its variations is a prerequisite for successful endodontic treatment. This case report describes an endodontic treatment where there was an intercurrence, generating deviation and perforation, which was solved with the aid of guided endodontics. A 37 years old, ASA1, was referred to the clinic for localisation and treatment of a calcified canal of the second right upper premolar. The tomographic images revealed the presence of only one canal and deviation with apical perforation. With the help of CBCT and CAD/CAM, it was possible to perform the guided access technique even after deviation and root perforation. Once again, this technique proved to be safe and predictable, allowing for a favourable prognosis in the long term. 相似文献
83.
Camile Ludovico Zamboti Carlos Augusto Marçal Camillo Amanda Paula Ricardo Rodrigues da Cunha Thaiuana Maia Ferreira Christiane Souza Guerino Macedo 《Revista brasileira de fisioterapia (S?o Carlos (S?o Paulo, Brazil))》2021,25(2):156-161
ObjectiveTo compare the performance, reliability, and validity of functional tests between women with and without patellofemoral pain.MethodsTwenty women with a diagnosis of patellofemoral pain between 18 and 40 years of age and 20 age-matched pain-free controls participated in the study. All participants performed a set of five function tests: sitting-rising test, sit-to-stand in 30 seconds, stair-climb test, stair descent test, and six-minute step test. To investigate reliability, participants were assessed on two different days, seven days apart, by two independent investigators blinded to the results of the other investigator. Validity was evaluated through associations with the results on the Anterior Knee Pain Scale.ResultsPerformance in the tests was worse in women with patellofemoral pain than in the control group for the sit-to-stand in 30 seconds (mean difference [MD] 3.4reps; 95%CI: 0.4, 6.4), stair-climb test (MD: 0.36 s; 95%CI: 0.1, 0.63), and six-minute step test (MD: 45reps; 95%CI: 20, 70). No differences were observed for the sitting-rising and stair descent tests. All tests in both groups showed moderate to excellent intra- and inter-rater reliability (intraclass correlation coefficients: 0.61 to 0.91 and 0.72 to 0.96, respectively). Finally, only the results on the sit-to-stand in 30 seconds test correlated with the Anterior Knee Pain Scale (r = 0.44, p = 0.047) in the patellofemoral pain group.ConclusionWomen with patellofemoral pain present lower performance on some functional tests. Functional tests are reliable in patients with patellofemoral pain, although they are not associated with the results on the Anterior Knee Pain Scale self-questionnaire. 相似文献
84.
85.
86.
87.
Robert A. Zimmermann Akira Muto Peter Fellner Chantal Ehresmann Christiane Branlant 《Proceedings of the National Academy of Sciences of the United States of America》1972,69(5):1282-1286
The distribution of ribosomal protein binding sites on the 16S ribosomal RNA molecule has been analyzed by limited ribonuclease hydrolysis of RNA-protein complexes, as well as by the interaction of individual proteins with RNA fragments purified from partial enzymatic digests. Of the six 30S subunit proteins known to interact directly with 16S RNA, proteins S4, S8, S15, S20, and, probably, S13 bind within a fragment produced by T(1) RNase (12S RNA) that comprises some 900 nucleotides and covers almost the entire 5'-terminal half of the 16S molecule. A fragment of 500-600 nucleotides (8S RNA) that is contiguous with 12S RNA and arises from the 3'-terminal portion of the 16S molecule is believed to contain the binding site for protein S7. Protein S15 interacts specifically with a sequence of about 135 nucleotides (4S RNA) that derives from 12S RNA after more extensive hydrolysis. Protein S4, but none of the other ribosomal proteins, binds to a 500-nucleotide fragment (9S RNA), generated by pancreatic RNase, that lies at the 5'-terminus of 16S RNA and is completely overlapped by the 12S fragment. A preliminary map of the binding sites is presented. 相似文献
88.
89.
Bartsch S Monnet J Selbach K Quigley F Gray J von Wettstein D Reinbothe S Reinbothe C 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(12):4933-4938
Thioredoxins (Trxs) are ubiquitous small proteins with a redox-active disulfide bridge. In their reduced form, they constitute very efficient protein disulfide oxidoreductases. In chloroplasts, two types of Trxs (f and m) coexist and play central roles in the regulation of the Calvin cycle and other processes. Here, we identified a class of Trx targets in the inner plastid envelope membrane of chloroplasts that share a CxxC motif approximately 73 aa from their carboxyl-terminal end. Members of this group belong to a superfamily of Rieske iron-sulfur proteins involved in protein translocation and chlorophyll metabolism. These proteins include the protein translocon protein TIC55, the precursor NADPH:protochlorophyllide oxidoreductase translocon protein PTC52, which operates as protochlorophyllide a-oxygenase, and the lethal leaf spot protein LLS1, which is identical with pheophorbide a oxygenase. The role of these proteins in dark/light regulation and oxidative control by the Trx system is discussed. 相似文献
90.
Angiotensin-(1-7): a novel peptide in the ovary 总被引:1,自引:0,他引:1
Costa AP Fagundes-Moura CR Pereira VM Silva LF Vieira MA Santos RA Dos Reis AM 《Endocrinology》2003,144(5):1942-1948
The present study was undertaken to investigate the presence of angiotensin-(1-7) [Ang-(1-7)] in the ovary and a possible role for it. Cycling female rats were killed in each phase of the estrous cycle, and ovarian Ang II and Ang-(1-7) were separated by HPLC and measured by RIA. The mean levels of Ang-(1-7) in proestrus and estrus were significantly higher than those in metestrus and diestrus (P < 0.05). Ang-(1-7) was also significantly higher in equine chorionic gonadotropin (eCG)-treated immature rats. Ang-(1-7) induced a significant increase in estradiol and progesterone production (P < 0.05) in the ovary of immature rats (24-25 d old) pretreated with eCG and perfused in a closed circuit system. This effect was blocked by A-779, a specific Ang-(1-7) antagonist (P < 0.05). The present data demonstrate the presence and physiological role of a novel renin-Ang system peptide in the ovary. The higher level of Ang-(1-7) in proestrus and estrus as well as in eCG-treated rats suggests the involvement of this renin-Ang system peptide in pre- and postovulatory events. 相似文献