全文获取类型
收费全文 | 15049篇 |
免费 | 807篇 |
国内免费 | 123篇 |
专业分类
耳鼻咽喉 | 98篇 |
儿科学 | 335篇 |
妇产科学 | 409篇 |
基础医学 | 1937篇 |
口腔科学 | 362篇 |
临床医学 | 1049篇 |
内科学 | 4252篇 |
皮肤病学 | 222篇 |
神经病学 | 1499篇 |
特种医学 | 610篇 |
外科学 | 2233篇 |
综合类 | 42篇 |
一般理论 | 1篇 |
预防医学 | 591篇 |
眼科学 | 162篇 |
药学 | 766篇 |
中国医学 | 23篇 |
肿瘤学 | 1388篇 |
出版年
2024年 | 13篇 |
2023年 | 98篇 |
2022年 | 210篇 |
2021年 | 433篇 |
2020年 | 228篇 |
2019年 | 318篇 |
2018年 | 413篇 |
2017年 | 307篇 |
2016年 | 343篇 |
2015年 | 378篇 |
2014年 | 594篇 |
2013年 | 729篇 |
2012年 | 1016篇 |
2011年 | 1039篇 |
2010年 | 678篇 |
2009年 | 616篇 |
2008年 | 1064篇 |
2007年 | 1049篇 |
2006年 | 941篇 |
2005年 | 1000篇 |
2004年 | 885篇 |
2003年 | 819篇 |
2002年 | 725篇 |
2001年 | 118篇 |
2000年 | 109篇 |
1999年 | 133篇 |
1998年 | 157篇 |
1997年 | 125篇 |
1996年 | 138篇 |
1995年 | 101篇 |
1994年 | 109篇 |
1993年 | 86篇 |
1992年 | 100篇 |
1991年 | 91篇 |
1990年 | 86篇 |
1989年 | 63篇 |
1988年 | 64篇 |
1987年 | 48篇 |
1986年 | 58篇 |
1985年 | 42篇 |
1984年 | 49篇 |
1983年 | 30篇 |
1982年 | 42篇 |
1981年 | 38篇 |
1980年 | 48篇 |
1979年 | 38篇 |
1978年 | 16篇 |
1977年 | 14篇 |
1976年 | 17篇 |
1971年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
Salvatore Caruso Agostino Serra Luigi Maiolino Carmela Agnello Lucia Di Mari Sara Ruta Angelo Arcidiacono Antonio Cianci 《The European journal of contraception & reproductive health care》2006,11(4):250-257
OBJECTIVE: To determine the effects of monophasic oral contraceptives on the nasal respiratory epithelium in premenopausal women. DESIGN: Prospective open clinical trial. SETTING: Outpatient Family Planning Centre. PATIENT(S): Eighty-eight premenopausal women, with ovulatory cycle, who were planning to take oral contraceptives. INTERVENTION(S): Baseline endovaginal ultrasound examination and blood test to measure serum progesterone to confirm ovulatory cycle. Thirty-eight women on pill containing 30 microg ethinylestradiol (EE) plus 75 microg gestodene, and 35 women on pill containing 15 microg ethinylestradiol plus 60 microg gestodene. MAIN OUTCOMES/MEASURE(S): Cytological changes on the nasal respiratory epithelium evaluated with the maturation index performed during the follicular, periovular, and luteal phases of the menstrual cycle, and on the sixth cycle of pill intake. RESULT(S): Hematoxylin-eosin staining for the maturation index showed similar trophic cytological aspects between the nasal and vaginal epithelium during the menstrual cycle and pill usage. Both the nasal and vaginal cytological samples showed higher maturation indexes during both the follicular and the periovular phases than during the luteal phase. Women on pill containing 15 microg EE showed lower trophic aspects in the nasal cytological samples compared with those on pill with 30 microg EE. CONCLUSION(S): Along with the vaginal cells, the nasal respiratory epithelium is an ovarian steroid target. The maturation index of the nasal respiratory epithelium seems to depend on the variation of the ovarian steroids during the menstrual cycle and on the iatrogenic effects of oral contraceptives. 相似文献
172.
Luigi Quintieri Cristina Geroni Marianna Fantin Rosangela Battaglia Antonio Rosato William Speed Paola Zanovello Maura Floreani 《Clinical cancer research》2005,11(4):1608-1617
PURPOSE: Nemorubicin (3'-deamino-3'-[2'(S)-methoxy-4'-morpholinyl]doxorubicin; MMDX) is an investigational drug currently in phase II/III clinical testing in hepatocellular carcinoma. A bioactivation product of MMDX, 3'-deamino-3',4'-anhydro-[2'(S)-methoxy-3'(R)-oxy-4'-morpholinyl]doxorubicin (PNU-159682), has been recently identified in an incubate of the drug with NADPH-supplemented rat liver microsomes. The aims of this study were to obtain information about MMDX biotransformation to PNU-159682 in humans, and to explore the antitumor activity of PNU-159682. EXPERIMENTAL DESIGN: Human liver microsomes (HLM) and microsomes from genetically engineered cell lines expressing individual human cytochrome P450s (CYP) were used to study MMDX biotransformation. We also examined the cytotoxicity and antitumor activity of PNU-159682 using a panel of in vitro-cultured human tumor cell lines and tumor-bearing mice, respectively. RESULTS: HLMs converted MMDX to a major metabolite, whose retention time in liquid chromatography and ion fragmentation in tandem mass spectrometry were identical to those of synthetic PNU-159682. In a bank of HLMs from 10 donors, rates of PNU-159682 formation correlated significantly with three distinct CYP3A-mediated activities. Troleandomycin and ketoconazole, both inhibitors of CYP3A, markedly reduced PNU-159682 formation by HLMs; the reaction was also concentration-dependently inhibited by a monoclonal antibody to CYP3A4/5. Of the 10 cDNA-expressed CYPs examined, only CYP3A4 formed PNU-159682. In addition, PNU-159682 was remarkably more cytotoxic than MMDX and doxorubicin in vitro, and was effective in the two in vivo tumor models tested, i.e., disseminated murine L1210 leukemia and MX-1 human mammary carcinoma xenografts. CONCLUSIONS: CYP3A4, the major CYP in human liver, converts MMDX to a more cytotoxic metabolite, PNU-159682, which retains antitumor activity in vivo. 相似文献
173.
Hans von der Maase Lisa Sengelov James T Roberts Sergio Ricci Luigi Dogliotti T Oliver Malcolm J Moore Annamaria Zimmermann Michael Arning 《Journal of clinical oncology》2005,23(21):4602-4608
PURPOSE: To compare long-term survival in patients with locally advanced or metastatic transitional cell carcinoma (TCC) of the urothelium treated with gemcitabine/cisplatin (GC) or methotrexate/vinblastine/doxorubicin/cisplatin (MVAC). PATIENTS AND METHODS: Efficacy data from a large randomized phase III study of GC versus MVAC were updated. Time-to-event analyses were performed on the observed distributions of overall and progression-free survival. RESULTS: A total of 405 patients were randomly assigned: 203 to the GC arm and 202 to the MVAC arm. At the time of analysis, 347 patients had died (GC arm, 176 patients; MVAC arm, 171 patients). Overall survival was similar in both arms (hazard ratio [HR], 1.09; 95% CI, 0.88 to 1.34; P = .66) with a median survival of 14.0 months for GC and 15.2 months for MVAC. The 5-year overall survival rates were 13.0% and 15.3%, respectively (P = .53). The median progression-free survival was 7.7 months for GC and 8.3 months for MVAC, with an HR of 1.09. The 5-year progression-free survival rates were 9.8% and 11.3%, respectively (P = .63). Significant prognostic factors favoring overall survival included performance score (> 70), TNM staging (M0 v M1), low/normal alkaline phosphatase level, number of disease sites (相似文献
174.
175.
Andre Beer-Furlan Alexander I. Evins Luigi Rigante Giulio Anichini Philip E. Stieg Antonio Bernardo 《Skull base》2014,75(3):187-197
Objective To investigate a novel dual-port endonasal and subtemporal endoscopic approach targeting midline lesions with lateral extension beyond the intracavernous carotid artery anteriorly and the Dorello canal posteriorly.
Methods Ten dual-port approaches were performed on five cadaveric heads. All specimens underwent an endoscopic endonasal approach from the sella to middle clivus. The endonasal port was combined with an anterior or posterior endoscopic extradural subtemporal approach. The anterior subtemporal port was placed directly above the middle third of the zygomatic arch, and the posterior port was placed at its posterior root. The extradural space was explored using two-dimensional and three-dimensional endoscopes.
Results The anterior subtemporal port complemented the endonasal port with direct access to the Meckel cave, lateral sphenoid sinus, superior orbital fissure, and lateral and posterosuperior compartments of the cavernous sinus; the posterior subtemporal port enhanced access to the petrous apex. Endoscopic dissection and instrument maneuverability were feasible and performed without difficulty in both the anterior and posterior subtemporal ports.
Conclusion The anterior and posterior subtemporal ports enhanced exposure and control of the region lateral to the carotid artery and Dorello canal. Dual-port neuroendoscopy is still minimally invasive yet dramatically increases surgical maneuverability while enhancing visualization and control of anatomical structures. 相似文献
176.
Early and late implant failure of submerged versus non‐submerged implant healing: A systematic review,meta‐analysis and trial sequential analysis
下载免费PDF全文
![点击此处可从《Journal of clinical periodontology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
177.
178.
ObjectiveMutations of the tumor suppressor gene TP53 are the most significant events in several human cancers. Few studies have analyzed the frequency of TP53 alterations in squamous cell carcinoma and adenocarcinoma of the cervix with controversial results. This study provides a detailed analysis of TP53 mutation spectra in cervical squamous cell carcinoma and adenocarcinoma from different geographical regions.MethodsThe analysis of TP53 mutational profiles was performed in 1353 cervical cancers retrieved from the IARC p53 mutation database (R15, 2010) and the COSMIC data along with the literature review of related studies identified by PubMed searching.ResultsThis analysis showed a significant higher mutation frequency of TP53 gene in cervical adenocarcinoma (32 of 241; 13.3%) compared to squamous cell carcinoma (39 of 657; 5.9%; P = 0.0003, χ2 test). The proportion of adenocarcinoma with mutated TP53 varied from 4% in North America to 19% in Asia. Among the six hot-spot codons of TP53 gene, three codons (175, 248 and 273) were the most commonly mutated in both types of cervical cancer, one codon (249) mainly in squamous cell carcinoma and one codon (282) only in adenocarcinoma. The G to A and C to T transitions were the prevalent type of mutations in both squamous cell carcinoma and adenocarcinoma (48.7% and 53.5% of all mutations, respectively). The frequency of C to A transversion was relatively high only in adenocarcinoma (25%), while the mirror mutation G to T was comparatively frequent in squamous cell carcinoma (14.6%).ConclusionsDifferent patterns of TP53 mutations occur in squamous cell carcinoma and adenocarcinoma of the cervix in different regions of the world. The highest frequency of mutated TP53 has been observed in cervical adenocarcinoma from Asia. Further studies are needed to better define the role of TP53 alterations in cervical cancer and possibly to understand the impact of mutations on cancer prognosis and outcomes. 相似文献
179.
180.