全文获取类型
收费全文 | 37680篇 |
免费 | 4403篇 |
国内免费 | 448篇 |
专业分类
耳鼻咽喉 | 342篇 |
儿科学 | 668篇 |
妇产科学 | 735篇 |
基础医学 | 2312篇 |
口腔科学 | 848篇 |
临床医学 | 8370篇 |
内科学 | 5703篇 |
皮肤病学 | 288篇 |
神经病学 | 1833篇 |
特种医学 | 750篇 |
外国民族医学 | 4篇 |
外科学 | 4464篇 |
综合类 | 3653篇 |
现状与发展 | 2篇 |
一般理论 | 7篇 |
预防医学 | 6481篇 |
眼科学 | 178篇 |
药学 | 3707篇 |
39篇 | |
中国医学 | 525篇 |
肿瘤学 | 1622篇 |
出版年
2024年 | 434篇 |
2023年 | 1059篇 |
2022年 | 1174篇 |
2021年 | 1933篇 |
2020年 | 2016篇 |
2019年 | 1975篇 |
2018年 | 1843篇 |
2017年 | 1749篇 |
2016年 | 1583篇 |
2015年 | 1684篇 |
2014年 | 2517篇 |
2013年 | 2946篇 |
2012年 | 2153篇 |
2011年 | 2253篇 |
2010年 | 1847篇 |
2009年 | 1787篇 |
2008年 | 1706篇 |
2007年 | 1631篇 |
2006年 | 1434篇 |
2005年 | 1244篇 |
2004年 | 1017篇 |
2003年 | 922篇 |
2002年 | 686篇 |
2001年 | 607篇 |
2000年 | 560篇 |
1999年 | 493篇 |
1998年 | 430篇 |
1997年 | 348篇 |
1996年 | 308篇 |
1995年 | 349篇 |
1994年 | 233篇 |
1993年 | 207篇 |
1992年 | 191篇 |
1991年 | 180篇 |
1990年 | 144篇 |
1989年 | 104篇 |
1988年 | 132篇 |
1987年 | 99篇 |
1986年 | 91篇 |
1985年 | 94篇 |
1984年 | 82篇 |
1983年 | 49篇 |
1982年 | 50篇 |
1981年 | 31篇 |
1980年 | 39篇 |
1979年 | 28篇 |
1978年 | 28篇 |
1977年 | 18篇 |
1975年 | 10篇 |
1973年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
High exposures to organic solvents among graffiti removers 总被引:3,自引:0,他引:3
Helena Anundi Marie-Louise Lind Lennart Friis Nadja Itkes Sven Langworth Christer Edling 《International archives of occupational and environmental health》1993,65(4):247-251
Summary The exposure to organic solvents among 12 graffiti removers was studied. Health effects were also assessed by structured interview and a symptom questionnaire. Blood and urine samples were collected at the end of the day of air sampling. The concentrations of dichloromethane, glycol ethers, trimethylbenzenes and N-methyl-2-pyrrolidinone in the breathing zone of each worker were measured during one working day. The 8-h time-weighted average exposure to dichloromethane ranged from 18 to 1200 mg/m3. The Swedish Permissible Exposure Limit value for dichloromethane is 120 mg/m3. The air concentrations of glycol ethers, trimethylbenzens and N-methyl-2-pyrrolidinone were low or not detectable. No exposure-related deviations in the serum concentrations of creatinine, aspartate transaminase, alanine transaminase, -glutamyl transpeptidase or hyaluronan or the urine concentrations of 1-microglobulin, R2-microglobulin or N-acetyl--glucos-aminidase were found. Irritative symptoms of the eyes and upper respiratory tract were more prevalent than in the general population. This study demonstrates that old knowledge about work harzards is not automatically transferred to new professions. Another aspect is that the public is also exposed as the job is performed during daytime in underground stations. At least for short periods, bystanders may be exposed to high concentrations of organic solvent vapours. People with predisposing conditions, e.g. asthmatics, may risk adverse reactions. 相似文献
82.
Antonio Mutti Enrico Bergamaschi Sergio Ghittori Marcello Imbriani Innocente Franchini 《International archives of occupational and environmental health》1993,65(Z1):S171-S176
Ambient and biological monitoring of hexane exposure were repeatedly carried out in 14 female shoe makers. Airborne hexane (Ci-H) was measured in 4-h samples collected by a diffusive method. Urinary spot samples were collected before, during (at noon), and at the end of a work shift. 2,5-Hexanedione (2,5HD) in urine collected at noon was poorly related to morning Ci-H. End-of-shift 2,5HD were also poorly related to afternoon air samples. The correlation was still relatively low when end-of-shift 2,5HD was related to 8-h TWA Ci-H (r= 0.44; P<0.01 on=" a=" linear=" scale,=" and=">0.01>r-0.58, P< 0.01=" on=" a=" log-log=" scale).=" end-of-shift=" 2,5hd=" levels=" estimated=" on=" the=" basis=" of=" pre-shift=" values=" using=" a=" mathematical=" model=" were=" much=" higher=" (2.3=" times=" on=" average)=" than=" those=" experimentally=" measured=" during=" the=" study=" period.=" owing=" to=" its=" relatively=" long=" half-time,=" 2,5hd=" seems=" to=" be=" influenced=" not=" only=" by=" current=" exposure,=" but=" also=" by=" hexane=" absorbed=" during=" the=" day(s)=" preceding=" sampling.=" the=" lack=" of=" a=" sampling=" strategy=" may=" account=" not=" only=" for=" inconsistencies=" between=" environmental=" and=" biological=" data,=" but=" also=" for=" a=" possible=" misuse=" of=" biological=" monitoring=" when=" utilized=" for=" risk=" assessment.=" despite=" sometimes=" poor=" correlations=" with=" ci-h,=" 2,5hd=" may=" still=" be=" preferred=" to=" other=" indicators=" as=" a=" marker=" of=" effective=" internal=" dose.=" a=" sampling=" strategy=" should=" ensure=" that=" measured=" values=" are=" representative=" of=" the=" individual=" risk=" for=" adverse="> 相似文献
83.
Measuring quality of life from the point of view of HIV-positive subjects: the HIV-QL31 总被引:2,自引:0,他引:2
A. Leplège N. Rude E. Ecosse R. Ceinos E. Dohin J. Pouchot 《Quality of life research》1997,6(6):585-594
Assessment of the quality of life (QoL) of human immunodeficiency virus (HIV)-infected subjects is often based on questionnaires in which the items or questions are not seen to be relevant by patients, nor by the users of the data obtained. It therefore seemed appropriate to return to the issue. The methodological and bibliographical research as well as the consultations we conducted convinced us that the elaboration of a new questionnaire was both necessary and possible. In order to do so, we adopted methodological principles based on the Sickness Impact Profile development methodology. First a bibliographical research was conducted in order to study instruments already used for HIV infection. Then, experts concerned with HIV infection and members of patients' associations were interviewed to assess how opportune the development of a new instrument could be. Following this, a methodology was established for the design and construction of the new instrument. One hundred and eighteen candidate questions were generated from an analysis of the content of 20 patients' interviews, which were subsequently submitted to 102 patients, to obtain finally a set of 31 questions from the interpretation of the results obtained from classic psychometric analysis and also from non-classic methods (item response theory and Rasch model). The concept being measured is the impact of illness being experienced by HIV-infected subjects from their own perspective. The range of health states covered by this questionnaire relates to fairly mild conditions. Rasch analysis of this set of 31 questions (HIV-QL31) shows that it corresponds to one unidimensional construct. A single score can be calculated by simple summation of dichotomous response options. This score is highly reliable (Cronbach's coefficient = 0.93) and is also discriminant regarding the severity of clinical status. 相似文献
84.
85.
Dr. Frank E. Block Jr MD Kris Minic Reynolds CFI John S. McDonald MD 《Journal of clinical monitoring and computing》1995,11(3):207-211
Automated anesthesia recordkeepers have been used to monitor patients during surgery in up to 90% of cases at The Ohio State University. The record-keeping devices are complex and can be difficult to troubleshoot. The 1st-CLASS Fusion Program, an expert system shell-program, has been programmed to allow the resident or nurse anesthetist to solve the two most common types of problems associated with the recordkeeper: printer problems and patient monitor problems. Use of this program allows the resident or nurse anesthetist to troubleshoot the recordkeeper quickly and accurately and promotes in the user a sense of competence and control over the technology. 相似文献
86.
Six mainstream and twelve sidestream infrared carbon dioxide (CO2) analysers were tested for accuracy of the CO2 display value, alarm activation and the effects of nitrous oxide (N2O), oxygen (O2) and water vapour according to the ISO Draft International Standard (DIS) #9918. Mainstream analysers (M-type): Novametrix Capnogard 1265; Hewlett Packard HP M1166A (CO2module HP M1016A); Datascope Passport; Marquette Tramscope 12; Nellcor Ultra Cap N-6000; Heilige Vicom-sm SMU 611/612 ETC. Sidestream analysers: Brüel &; Kjaer Type 1304; Datex Capnomac II; Marquette MGA-AS; Datascope Multinex; Ohmeda 4700 OxiCap (all type S1: respiratory cycles not demanded); Biochem BCI 9000; Bruker BCI 9100; Dräger Capnodig and PM 8020; Criticare Poet II; Heilige Vicom-sm SMU 611/612 A-GAS (all type S2: respiratory cycles demanded). The investigations were performed with premixed test gases (2.5, 5, 10 vol%, error ?1% rel.). Humidification (37° C) of gases were generated by a Dräger Aquapor. Respiratory cycles were simulated by manually activated valves. All monitors complied with the tolerated accuracy bias in CO2 reading (≤ 12% or 4 mmHg of actual test gas value) for wet and dry test gases at all concentrations, except that the Marquette MGA-AS exceeded this accuracy limit with wet gases at 5 and 10 vol% CO2. Water condensed in the metal airway adapter of the HP M1166A at 37° C gas temperature but not at 3(P C. The Servomex 2500 (nonclinical reference monitor), Passport (M-type), Multinex (S1-type) and Poet II (S2-type) showed the least bias for dry and wet gases. Nitrous oxide and O2 had practically no effect on the Capnodig and the errors in the others were max. 3.4 mmHg, still within the tolerated bias in the DIS (same as above). The difference between the display reading at alarm activation and the set point was in all monitors (except in the Capnodig: bias 1.75 mmHg at 5 vol% CO2) below the tolerated limit of the DIS (difference ≤ 0.2 vol%). The authors conclude that the tested monitors are safe for clinical use (except those failing the DIS limits). The accuracy of the CO2-reading (average of mean absolute bias) is better in the M-type than in the S1- or S2- type analysers although no statistical (nor clinical) significant differences could be detected. Most manufacturers work with stricter limits than those proposed by the DIS. 相似文献
87.
The nature of error detection as manifested by the error-related negativity was examined in both a Sternberg memory search task and a visual search task. Both tasks were performed in conditions with consistent or varied stimulus-response mapping and loads of three or six letters. After subjects were trained extensively in all conditions, they performed the tasks throughout the night without sleeping. The data suggest that the effectiveness of error detection decreases over time because of a decrease in the quality of perceptual processing. Error detection also suffers when performance requires more search-related resources. In both cases, the representation of the correct response is compromised. These results indicate that error detection depends on the same perceptual and cognitive processes that are required for correct performance. 相似文献
88.
Ambulatory urodynamic monitoring of external urethral sphincter behavior in chronic prostatitis patients 总被引:3,自引:0,他引:3
Aim: To study the behavior of external urethral sphincter in chronic prostatitis (CP) patient under natural filling.Methods: Twenty-one CP patients and 17 normal volunteers were involved in the study. Both the patients andvolunteers underwent ambulatory urodynamic monitoring (AM) and conventional medium filling cystometry (CMG).Urodec 500 was used for AM and Menuet for CMG. AM findings from CP patients were compared with those fromnormal volunteers, and the results from AM were compared with those from CMG. Results: In AM, the restingand voiding external urethral sphincter (EUS) pressures and maximum urethral closure pressures (MUCP) weresignificantly higher in CP patients [ ( 121.5 ±10.3) and (85.6±3.5) cm water, respectively ] than in normalvolunteers [ (77.6±11.4) and (10.3±1.6) cm water, respectively)]. Conclusion: The behavioral changes ofEUS in CP patients included spasm and instability of EUS, which were demonstrated using AM under natural filling;the findings were also in accord with the res 相似文献
89.
采用高效液相色谱法,以水乙腈三乙胺(325∶175∶22 ,用磷酸调p H 至3 .0) 为流动相,在λ= 240 nm 进行检测。该方法可使乳酸诺氟沙星和乳酸甲氧苄氨嘧啶达到良好分离。该方法操作简便、灵敏、重现性好。 相似文献
90.
Purpose: To investigate the compliance of the patients with ocular fundus diseases with recommendation for follow-up examination after laser treatment, and the underlying reasons for non-compliance.Methods: 53 patients with ocular fundus disease were asked to fill in a questionnaire which includes the socio-demographic characteristics, fear of the fundus disease, conception of the laser treatment and the motivation for staying healthy. Variables were compared for the compliers group and the non-compliers group by chi-square test. Result; Of the 53 subjects, 35 were classified as non-compliers and 18 were classified as compliers. There was no statistically significant difference between the two groups on all selected socio-demographic factors, conception of the laser treatment and the motivation for staying healthy. Significant difference was found between the two groups on two of those items concerning the fear of the diseases (P<0. 05). About half of the participants showed the lack of knowledge about 相似文献