全文获取类型
收费全文 | 334264篇 |
免费 | 27330篇 |
国内免费 | 8068篇 |
专业分类
耳鼻咽喉 | 4144篇 |
儿科学 | 6541篇 |
妇产科学 | 5418篇 |
基础医学 | 23512篇 |
口腔科学 | 9932篇 |
临床医学 | 34504篇 |
内科学 | 39193篇 |
皮肤病学 | 4677篇 |
神经病学 | 16657篇 |
特种医学 | 9728篇 |
外国民族医学 | 49篇 |
外科学 | 32805篇 |
综合类 | 51207篇 |
现状与发展 | 32篇 |
一般理论 | 26篇 |
预防医学 | 34978篇 |
眼科学 | 4032篇 |
药学 | 30602篇 |
424篇 | |
中国医学 | 34962篇 |
肿瘤学 | 26239篇 |
出版年
2024年 | 1241篇 |
2023年 | 6402篇 |
2022年 | 11873篇 |
2021年 | 15744篇 |
2020年 | 15263篇 |
2019年 | 16172篇 |
2018年 | 14420篇 |
2017年 | 13272篇 |
2016年 | 12641篇 |
2015年 | 12013篇 |
2014年 | 23038篇 |
2013年 | 25770篇 |
2012年 | 19973篇 |
2011年 | 21341篇 |
2010年 | 17353篇 |
2009年 | 15448篇 |
2008年 | 14568篇 |
2007年 | 15013篇 |
2006年 | 13063篇 |
2005年 | 11244篇 |
2004年 | 9230篇 |
2003年 | 8249篇 |
2002年 | 6526篇 |
2001年 | 5577篇 |
2000年 | 4811篇 |
1999年 | 3848篇 |
1998年 | 3125篇 |
1997年 | 2743篇 |
1996年 | 2248篇 |
1995年 | 2082篇 |
1994年 | 1782篇 |
1993年 | 1488篇 |
1992年 | 1352篇 |
1991年 | 1229篇 |
1990年 | 1076篇 |
1989年 | 1009篇 |
1988年 | 946篇 |
1987年 | 834篇 |
1986年 | 734篇 |
1985年 | 2031篇 |
1984年 | 2271篇 |
1983年 | 1442篇 |
1982年 | 1864篇 |
1981年 | 1338篇 |
1980年 | 1145篇 |
1979年 | 1015篇 |
1978年 | 806篇 |
1977年 | 595篇 |
1976年 | 740篇 |
1975年 | 510篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
101.
S E Irwin G Y Kwei G R Blackburn R Thurman F C Kauffman 《Environmental and molecular mutagenesis》1992,19(3):253-258
Comparison of the mutagenicity of nine isomeric benzo(a)pyrenyl [B(a)P] phenols conjugated with either sulfate or glucuronide was carried out using strain Salmonella typhimurium TA98. Of the nine conjugates tested, only B(a)P-1-sulfate was mutagenic. Accordingly, the mutagenicity of B(a)P-1-sulfate was compared with that of B(a)P and 1-hydroxybenzo(a)pyrene [B(a)P-1-OH] in the presence and absence of rat lung S9 and Aroclor-induced liver S9 with and without an NADPH-generating system. B(a)P-1-sulfate was slightly mutagenic, whereas B(a)P and the 1-hydroxy derivative were nonmutagenic when S9 fractions and NADPH were omitted. Addition of induced liver S9 with NADPH caused mutagenicity with B(a) -1-OH greater than B(a)P greater than B(a)P-1-sulfate. B(a)P-1-sulfate was the only mutagenic species when lung S9 was added. This mutagenicity did not require NADPH. Sodium sulfite, an inhibitor of arylsulfatase, decreased the mutagenicity of B(a)P-1-sulfate. These data suggest that a unique mutagenic species is generated from B(a)P-1-sulfate via arylsulfatase in rat lung. 相似文献
102.
MD MPHCecilia Albala MD MScMabel Y ez MPh Mat.Sc.Gabriela Salazar MD MPHFernando Vio 《Nutrition Research》1994,14(12):1797-1809
Body composition measured with isotopic dilution was compared with anthropometric measurements. The study was carried out in 47 subjects from both sexes, 65 to 92 years old. Total body water (TBW), anthropometric measurements, and dynamometry were assessed. TBW was significatively higher in men than women and decreased with age. Dynamometry and fatfree mass were well correlated (r=0.73 in males and r=0.58 in females) and significantly different between sexes. A negative correlation was found for dynamometry with age, being significant for women. Linear regression equations to predict TBW from anthropometric measurements in males and females were obtained: Males: TBW(I)=19.349+0.617 weight(kg) — 0.931 mid-arm circumference(cm)+0.122 dynamometry (kg) Females: TBW(l)=−5.531+0.343 weight(kg)-0.213 triceps skinfold (mm)+ 0.148 dynamometry(kg) + 3.424 wrist diameter (cm). This simple model is proposed for use in epidemiological and field studies where other more sophisticated methods can not be applied. 相似文献
103.
光动力学疗法与局部化疗联合治疗进展期食管贲门癌 总被引:2,自引:0,他引:2
作应用光动力学疗法(PDT)对进展期食管贲门癌55例进行治疗,并对其中15例联合应用内镜下局部注射抗癌药物。对每一患均先静脉滴注血卟啉衍生物(HPD)5mg/kg,于用药后24,48和72h分别用波长630nm的铜蒸汽激光照射肿瘤部位。联合治疗组除PDT治疗外,于每次光照前肿瘤局部注射5-Fu250~500mg。结果:联合治疗组的近期显效率高于单纯PDT组(P〈0.05)。病例随访6~16月, 相似文献
104.
Kay Teschke Susan M. Kennedy Andrew F. Olshan 《American journal of industrial medicine》1994,26(3):327-337
During an exposure monitoring study, 78 saw maintenance tradesmen were randomly assigned to be interviewed about their exposures using one of two questionnaire formats: open-ended and partly prompted questions about five categories of materials; and detailed prompting about 75 agents. The more open-ended questionnaire elicited fewer exposure responses overall, but more responses about agents not included on the detailed questionnaire. Composite materials and trade name products were more frequently cited as exposures than individual metals or compounds. Validity of responses was ascertained using air measurements (individual metals) or observations of the employees (composite materials). Sums of sensitivities and specificities were very low (near 1.0) for most of the metals for both types of questionnaire. For composite materials, validity improved substantially. Sensitivities with the partly prompted format (0.44–0.85) were always lower than with detailed prompting (0.80–1.00). Specificities were usually, but not always, higher with partial prompting (0.66–0.92) than with detailed prompting (0.18–0.86). Selection of questionnaire format for an epidemiologic study would depend on the likely prevalence of exposure in controls and the effects of trade-offs in sensitivity and specificity. 相似文献
105.
Thomas M. Gehring PhD Daniel Marti MS MD Andrea Sidler MA 《Child psychiatry and human development》1994,25(2):125-138
Perceptions of family cohesion and hierarchy structures were assessed by theFamily System Test (FAST), a clinically-derived figure placement technique. Parents (N=140) and their preadolescent offspring (N=70) completed typical and conflict representations in individual as well as group settings. Typical representations were characterized by balanced family structures (i.e. cohesive and moderately hierarchical) and those displaying conflict situations showed predominantly unbalanced patterns. FAST portrayals were related to respondent (mother vs. father vs. child). Fathers represented typical family relations as balanced more often than mothers. Regarding conflict representations, children were more likely than fathers to portray the family as unbalanced. However, analyses of representations of the same family (i.e. intra-family comparisons) indicated that all respondents differed in their perceptions and, that fathers' typical portrayals showed most often the same structure as those done by the family members as a group. 相似文献
106.
Recombinant human deoxyribonuclease I (rhDNase) is a new therapeutic agent developed to improve clearance of purulent sputum from the human airways. It is delivered by inhalation. Four jet nebulizers, T Up-Draft II (Hudson), Customized Respirgard II (Marquest), Acorn II (Marquest), and Airlife Misty (Baxter), were evaluated in vitro for their ability to deliver aerosols of rhDNase. The aerosols were generated from 2.5-mL aqueous solutions of rhDNase, at concentrations of either 1 or 4 mg/mL. In all experiments, the Pulmo-Aide Compressor (De Vilbiss) was used to supply the air to the nebulizers. Between 20 and 28% of the rhDNase dose initially placed in the nebulizers was delivered to the mouthpiece in the respirable range (1-6 µm). Evaluation of the rhDNase following nebulization in all four devices indicated that there was no loss in enzymatic activity and no increase in aggregation. Circular dichroism spectrophotometry indicated there was no change in either the secondary or the tertiary structure in rhDNase following nebulization. These results show that all four nebulizers are essentially equivalent in their ability to deliver respirable doses of rhDNase in an intact, fully active form. Changing the concentration of the solution in the nebulizer from 4 to 1 mg/mL rhDNase leads to a proportional reduction in the respirable dose delivered to the mouthpiece. 相似文献
107.
前列腺癌去雄激素治疗不良反应的预防和处理 总被引:1,自引:0,他引:1
目的观察去雄激素治疗前列腺癌的不良反应,并探讨其预防和治疗。方法回顾性分析1998年7月-2006年1月112例去雄激素治疗晚期前列腺癌的临床资料。结果112例患者中,97例完成了不良反应的调查。随访3-36月,去雄激素治疗后潮热、性功能障碍、病理性骨折发生率分别为46%、75%、4%;患者潮热、精神疲乏、四肢乏力、纳差症状明显加重(P<0.05);性功能明显减退(P<0.05)。12例潮热症状严重者使用抗抑郁药博乐欣(25mg,tid)1-2周症状减轻。7例有骨转移性疼痛或严重骨质疏松患者,应用唑来膦酸4mg静脉滴注,每45d一次,骨痛症状缓解。结论去雄激素对前列腺癌患者生活质量有一定影响。博乐欣可减轻患者潮热症状,唑来膦酸可预防和治疗去雄激素相关的骨质疏松并发症。 相似文献
108.
Madhuri Dadwal Chander Mohan D. R. Sharma 《Indian journal of otolaryngology and head and neck surgery》2007,59(3):261-263
Secondary tuberculosis of pharynx is a rare condition as pharynx is not a common site for clinically manifest tuberculosis.
A rare and unusual case of secondary oropharyngeal tuberculosis in a 40 years male patient, who presented with an ulceroproliferative
lesion of oropharynx extending to nasopharynx and laryngopharynx is being reported. 相似文献
109.
An out line of the scheme of training specialists in Otorhinolaryngology-Head and Neck Surgery (ORL-HNS) in South Africa is
given and the difference with Indian training discussed 相似文献
110.
Intra-articular fractures of the proximal tibia present a wide spectrum of injury patterns with associated soft tissue injury. The last two decades have seen the techniques of management evolve from extensive open reduction and rigid internal fixation to arthroscopy-assisted minimal invasive surgery (MIS) and biologically benign internal fixation. The ultimate aim is to prevent the occurrence of late degenerative arthritis. This could be achieved in selected patients using minimal invasive surgery, which offers the advantages of better visualisation and management of intra-articular soft tissue injuries, confirmation of fracture reduction viewed from the joint surface, faster rehabilitation and fewer wound complications. 相似文献