全文获取类型
收费全文 | 5959篇 |
免费 | 422篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 125篇 |
儿科学 | 178篇 |
妇产科学 | 114篇 |
基础医学 | 704篇 |
口腔科学 | 210篇 |
临床医学 | 556篇 |
内科学 | 1256篇 |
皮肤病学 | 117篇 |
神经病学 | 599篇 |
特种医学 | 210篇 |
外科学 | 969篇 |
综合类 | 89篇 |
一般理论 | 3篇 |
预防医学 | 346篇 |
眼科学 | 104篇 |
药学 | 320篇 |
中国医学 | 9篇 |
肿瘤学 | 508篇 |
出版年
2023年 | 57篇 |
2022年 | 126篇 |
2021年 | 209篇 |
2020年 | 127篇 |
2019年 | 177篇 |
2018年 | 185篇 |
2017年 | 122篇 |
2016年 | 176篇 |
2015年 | 171篇 |
2014年 | 233篇 |
2013年 | 292篇 |
2012年 | 458篇 |
2011年 | 444篇 |
2010年 | 243篇 |
2009年 | 218篇 |
2008年 | 343篇 |
2007年 | 322篇 |
2006年 | 317篇 |
2005年 | 287篇 |
2004年 | 295篇 |
2003年 | 264篇 |
2002年 | 226篇 |
2001年 | 82篇 |
2000年 | 93篇 |
1999年 | 66篇 |
1998年 | 41篇 |
1997年 | 37篇 |
1996年 | 49篇 |
1995年 | 33篇 |
1994年 | 34篇 |
1993年 | 35篇 |
1992年 | 69篇 |
1991年 | 58篇 |
1990年 | 46篇 |
1989年 | 40篇 |
1988年 | 31篇 |
1987年 | 36篇 |
1986年 | 35篇 |
1985年 | 23篇 |
1984年 | 22篇 |
1983年 | 25篇 |
1982年 | 18篇 |
1981年 | 23篇 |
1980年 | 21篇 |
1978年 | 17篇 |
1977年 | 23篇 |
1976年 | 14篇 |
1975年 | 19篇 |
1974年 | 16篇 |
1972年 | 22篇 |
排序方式: 共有6417条查询结果,搜索用时 31 毫秒
71.
72.
Microsomal monooxygenases catalyze the biosynthesis of epoxides from olefinic and aromatic compounds whilst microsomal epoxide hydratase and cytoplasmic glutathione S-transferases are responsible for their further biotransformation. Although catalytically very efficient the cytoplasmic glutathione S-transferases play, due to their subcellular localization, a minor role in the inactivation of epoxides derived from large lipophilic compounds and were, therefore, not included in this study. It was shown with such a lipophilic compound, benzo(a)pyrene, as a model substance and with liver enzyme mediated bacterial mutagenesis as biological endpoint that species and strain differences in epoxide hydratase and monooxygenases are reflected in very dramatic differences in mutagenicity of benzo(a)pyrene which varied from extremely potent to a degree which could easily be overlooked. In order to investigate whether the differences in enzyme activities were causally linked to the observed differences in mutagenicity, the enzyme activities were modulated by inhibition and induction. These manipulations were always accompanied by the corresponding changes in mutagenicity.It is concluded that species such as mice which possess high monooxygenase activity but very low epoxide hydratase activity are much more susceptible than man to those toxic effects which are mediated by metabolically formed epoxides which are substrates of epoxide hydratase. In this regard, it is especially noteworthy that mice possess a much lower hepatic epoxide hydratase activity than man.Presented at the Symposium Influence of Metabolic Activations and Inactivations on Toxic Effects held at the 18th Spring Meeting of the Deutsche Pharmakologische Gesellschaft, Section Toxicology, D-6500 Mainz, March 15, 1977 相似文献
73.
74.
The aim of this paper is to review the current knowledge of phantom tooth pain, a neuropathic facial pain disorder, thought to result from peripheral nerve injury. Phantom tooth pain is a deafferentation pain disorder of persistent toothache in teeth that have been denervated (usually by root canal treatment) or pain in the area formerly occupied by teeth prior to their extraction. The pain usually extends to the facial structures adjacent to tissues that have undergone deafferentation. The clinical characteristics, differential diagnosis, epidemiology, and treatment of phantom tooth pain are reviewed. Suggestions for further research include the need for controlled treatment trials and modification of current criteria. CONCLUSIONS: Phantom tooth pain has much in common with other phantom pain disorders. In the absence of controlled clinical trials specifically directed to phantom tooth pain, treatment should be guided by standards used for other neuropathic pain disorders. Revised diagnostic criteria for phantom tooth pain are proposed. 相似文献
75.
76.
Raphael P Viscidi Mark Schiffman Allan Hildesheim Rolando Herrero Philip E Castle Maria C Bratti Ana Cecilia Rodriguez Mark E Sherman Sophia Wang Barbara Clayman Robert D Burk 《Cancer epidemiology, biomarkers & prevention》2004,13(2):324-327
Whether antibodies to human papillomavirus (HPV) capsids, elicited by natural infection, are protective is unknown. This question was addressed in a population-based cohort of 7046 women in Costa Rica by examining the association between baseline seroreactivity to HPV-16, HPV-18, or HPV-31 virus-like particles and the risk of subsequent HPV infection at a follow-up visit 5-7 years after enrollment. Seropositivity to HPV-16, HPV-18, or HPV-31 was not associated with a statistically significant decreased risk of infection with the homologous HPV type [relative risk (RR) and [95% confidence interval (CI)], 0.74 (0.45-1.2), 1.5 (0.83-2.7), and 0.94 (0.48-1.8), respectively]. Seropositivity to HPV-16 or HPV-31 was not associated with a decreased risk of infection with HPV-16 or its genetically related types [RR (95% CI), 0.82 (0.61-1.1) and 0.93 (0.68-1.2), respectively]. Seropositivity to HPV-18 was not associated with a decreased risk of infection with HPV-18 or its genetically related types (RR 1.3; 95% CI 1.0-1.8). Thus, we did not observe immunity, although a protective effect from natural infection cannot be excluded because of the limits of available assays and study designs. 相似文献
77.
Randomized, placebo-controlled trial of combined pentoxifylline and tocopherol for regression of superficial radiation-induced fibrosis. 总被引:3,自引:0,他引:3
Sylvie Delanian Raphael Porcher Saida Balla-Mekias Jean-Louis Lefaix 《Journal of clinical oncology》2003,21(13):2545-2550
PURPOSE: Radiation-induced fibrosis (RIF) is a rare morbid complication of radiotherapy, without an established method of management. RIF treatment with a combination of pentoxifylline (PTX) and alpha-tocopherol (vitamin E; Vit E) was recently prompted by the good results of a clinical trial and an animal study. The present double-blind, placebo-controlled, monocentric study was designed to assess the efficacy of this combination in treating RIF sequelae. PATIENTS AND METHODS: Twenty-four eligible women with 29 RIF areas involving the skin and underlying tissues were enrolled from December 1998 to April 2000. These patients, previously irradiated for breast cancer, were randomly assigned to four balanced treatment groups: (A) 800 mg/d of PTX and 1,000 U/d of Vit E; (B) PTX plus placebo; (C) placebo plus Vit E; and (D) placebo-placebo. The main end point measure was the relative regression of measurable RIF surface after 6 months of treatment. Assessment was completed by depth (with ultrasonography) and associated symptom measures. RESULTS: Twenty-two patients with 27 RIF areas were analyzed at 6 months. Mean RIF surface regression was significant with combined PTX/Vit E versus double placebo (60% +/- 10% v 43% +/- 17%; P =.038). The median slope for the speed of RIF surface area and volume regression was significantly higher for group A than groups B, C, and D. All treatments were well tolerated. CONCLUSION: Six months' treatment of combined PTX/Vit E can significantly reduce superficial RIF. Synergism between PTX and Vit E is likely, as treatment with each drug alone is ineffective, but these results require confirmation in larger series. 相似文献
78.
Ravi Salgia Thomas Lynch Arthur Skarin Joan Lucca Cathleen Lynch Ken Jung F Stephen Hodi Michael Jaklitsch Steve Mentzer Scott Swanson Jean Lukanich Raphael Bueno John Wain Douglas Mathisen Cameron Wright Panos Fidias Dean Donahue Shirley Clift Steve Hardy Donna Neuberg Richard Mulligan Iain Webb David Sugarbaker Martin Mihm Glenn Dranoff 《Journal of clinical oncology》2003,21(4):624-630
PURPOSE: We demonstrated that vaccination with irradiated tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates potent, specific, and long-lasting antitumor immunity in multiple murine models and patients with metastatic melanoma. To test whether this vaccination strategy enhances antitumor immunity in patients with metastatic non-small-cell lung cancer (NSCLC), we conducted a phase I clinical trial. PATIENTS AND METHODS: Resected metastases were processed to single-cell suspension, infected with a replication-defective adenoviral vector encoding GM-CSF, irradiated, and cryopreserved. Individual vaccines consisted of 1 x 10(6), 4 x 10(6), or 1 x 10(7) cells, depending on overall yield, and were administered intradermally and subcutaneously at weekly and biweekly intervals. RESULTS: Vaccines were successfully manufactured for 34 (97%) of 35 patients. The average GM-CSF secretion was 513 ng/10(6) cells/24 h. Toxicities were restricted to grade 1 to 2 local skin reactions. Nine patients were withdrawn early because of rapid disease progression. Vaccination elicited dendritic cell, macrophage, granulocyte, and lymphocyte infiltrates in 18 of 25 assessable patients. Immunization stimulated the development of delayed-type hypersensitivity reactions to irradiated, dissociated, autologous, nontransfected tumor cells in 18 of 22 patients. Metastatic lesions resected after vaccination showed T lymphocyte and plasma cell infiltrates with tumor necrosis in three of six patients. Two patients surgically rendered as having no evidence of disease at enrollment remain free of disease at 43 and 42 months. Five patients showed stable disease durations of 33, 19, 12, 10, and 3 months. One mixed response was observed. CONCLUSION: Vaccination with irradiated autologous NSCLC cells engineered to secrete GM-CSF enhances antitumor immunity in some patients with metastatic NSCLC. 相似文献
79.
Shevach Friedler M.D. Arieh Raziel M.D. Yigal Soffer M.D. Deborah Strassburger Ph.D. Dafna Komarovsky B.Sc. Raphael Ron-El M.D. 《Fertility and sterility》1997,68(5):892-897
Objective: To compare the outcome of intracytoplasmic sperm injection (ICSI) with fresh and frozen-thawed testicular spermatozoa in patients with nonobstructive azoospermia.Design: Retrospective analysis of consecutive ICSI cycles.Setting: In Vitro Fertilization Unit, Assaf Harofeh Medical Center.Patient(s): Eighteen with nonobstructive azoospermia in whom testicular sperm was found after testicular sperm extraction.Intervention(s): Testicular sperm retrieval, cryopreservation, and ICSI with fresh or frozenthawed testicular spermatozoa.Main Outcome Measure(s): Two-pronuclear fertilization; embryo cleavage rates, mean number of embryos transferred per cycle, and their relative quality, embryo implantation, clinical pregnancy, and ongoing pregnancy rates (PRs) per ET.Result(s): No statistically significant differences were noted in all parameters examined between ICSI cycles with fresh or cryopreserved testicular spermatozoa from the same nine patients and comparing all ICSI cycles performed; with fresh (25 cycles) and thawed (14 cycles) testicular spermatozoa, respectively: two-pronuclear fertilization, 47% versus 44%; embryo cleavage rates, 94% versus 89%; implantation rates, 9% versus 11%; and clinical PR, 26% versus 27%. The delivery or ongoing PR using fresh sperm was better (21% versus 9%), but the difference did not reach statistical significance. The cumulative clinical PRs and ongoing PRs per testicular sperm extraction procedure were 36% and 24%, respectively.Conclusion(s): Testicular sperm cryopreservation using a simple freezing protocol is promising in patients with nonobstructive azoospermia augmenting the overall success achieved after surgical sperm retrieval. (Fertility Sterility 1997;68:892-7. C 1997 by American Society for Reproductive Medicine.) 相似文献
80.
Early stage nasopharyngeal carcinoma: radiotherapy dose and time factors in tumor control 总被引:1,自引:0,他引:1
Chang JT; See LC; Liao CT; Chen LH; Leung WM; Chen SW; Chen WC 《Japanese journal of clinical oncology》1998,28(3):207-213
OBJECTIVE: To evaluate radiotherapy dose and length of treatment in the
control of early stage nasopharyngeal carcinoma (NPC) treated with a
combination of external radiotherapy and brachytherapy, MATERIALS &
METHODS: We reviewed the records of 133 patients with early stage
nasopharyngeal carcinoma (stage I or II, AJC/UICC staging system) who
received definitive radiotherapy in Chang Gung Memorial Hospital from 1979
to 1991. The median follow-up time was 7.1 years with a minimum of 2 years.
All patients were treated with megavoltage external radiotherapy to the
nasopharynx area (63-72 Gy) followed by high dose rate intracavitary
brachytherapy (5-16.5 Gy in one to three fractions, spaced 1-2 weeks
apart). The median total dose and time of irradiation was 75 Gy (69.8-81.4
Gy) and 11.6 weeks (7.8-20 weeks) respectively. Survival analysis was used
to examine the effect of several variables on prognosis. RESULTS: The
5-year rates were 86.4% for local control, 84.7% for disease free survival,
88.5% for actuarial survival and 84.2% for overall survival. The treatment
group (combination of time and dose of irradiation) was the most important
prognostic factor according to Cox's proportional hazard model. Patients
receiving radiation at a total dose of < or = 75 Gy completed in < 12
weeks showed the best prognosis. CONCLUSION: Treatment time and total
treatment dose are both important factors in treating early stage NPC.
Decreasing the total radiation time to < 12 weeks and not exceeding a
radiation dose of 75 Gy gave the best results.
相似文献