全文获取类型
收费全文 | 7612篇 |
免费 | 589篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 103篇 |
儿科学 | 208篇 |
妇产科学 | 192篇 |
基础医学 | 997篇 |
口腔科学 | 112篇 |
临床医学 | 900篇 |
内科学 | 1470篇 |
皮肤病学 | 77篇 |
神经病学 | 783篇 |
特种医学 | 735篇 |
外科学 | 1027篇 |
综合类 | 72篇 |
一般理论 | 4篇 |
预防医学 | 516篇 |
眼科学 | 118篇 |
药学 | 433篇 |
中国医学 | 3篇 |
肿瘤学 | 477篇 |
出版年
2023年 | 41篇 |
2022年 | 54篇 |
2021年 | 135篇 |
2020年 | 105篇 |
2019年 | 137篇 |
2018年 | 158篇 |
2017年 | 123篇 |
2016年 | 135篇 |
2015年 | 150篇 |
2014年 | 194篇 |
2013年 | 293篇 |
2012年 | 388篇 |
2011年 | 501篇 |
2010年 | 289篇 |
2009年 | 287篇 |
2008年 | 439篇 |
2007年 | 431篇 |
2006年 | 439篇 |
2005年 | 388篇 |
2004年 | 366篇 |
2003年 | 299篇 |
2002年 | 278篇 |
2001年 | 228篇 |
2000年 | 205篇 |
1999年 | 189篇 |
1998年 | 78篇 |
1997年 | 76篇 |
1996年 | 60篇 |
1995年 | 45篇 |
1994年 | 53篇 |
1993年 | 38篇 |
1992年 | 122篇 |
1991年 | 98篇 |
1990年 | 111篇 |
1989年 | 97篇 |
1988年 | 86篇 |
1987年 | 76篇 |
1986年 | 75篇 |
1985年 | 90篇 |
1984年 | 72篇 |
1983年 | 61篇 |
1982年 | 47篇 |
1981年 | 40篇 |
1980年 | 35篇 |
1979年 | 53篇 |
1978年 | 40篇 |
1974年 | 40篇 |
1973年 | 33篇 |
1972年 | 31篇 |
1970年 | 34篇 |
排序方式: 共有8227条查询结果,搜索用时 390 毫秒
31.
Acute hypertensive responses during nitrous oxide-opioid-relaxant anesthesia are a common clinical problem. In adult men undergoing radical prostatectomy procedures and anesthetized with a standardized technique, we evaluated the effectiveness of alfentanil, isoflurane, and trimethaphan in treating acute hemodynamic and stress hormone responses to surgical stimulation. Stress hormone concentrations were measured 1 min before skin incision, after the onset of an acute hypertensive response, and after returning the mean arterial pressure to within 10% of the preincision values with one of the three treatment modalities. Pretreatment plasma alfentanil concentrations (151 +/- 47 to 156 +/- 47 ng.ml-1) and end-tidal nitrous oxide concentrations (66 +/- 2 to 68 +/- 2%) were similar in all three groups. Acute hypertensive events were associated with significantly increased concentrations of catecholamines and vasopressin (antidiuretic hormone [ADH]). Whereas intravenous alfentanil returned all hormone concentrations to preincision values, norepinephrine and glucose concentrations were significantly increased after adjunctive isoflurane administration. Although trimethaphan decreased the norepinephrine concentration, the epinephrine, beta-endorphin, cortisol, ADH, and glucose concentrations were significantly increased compared to preincision values. However, the persistent elevation in the posttreatment ADH concentration in the trimethaphan group was the only significant difference between the three groups. Mean (+/- standard deviation) times to awakening (2.8 +/- 3.3 to 3.8 +/- 4.2 min), extubation (8.1 +/- 4.8 to 10.3 +/- 8.5 min), and orientation (19.6 +/- 20.4 to 24.6 +/- 19.1 min) were similar in all three groups. Naloxone was required more frequently in patients in the alfentanil (35%) and isoflurane (24%) groups than in the trimethaphan group (4%).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
32.
Image quality and safety of magnetic resonance (MR) imaging were evaluated in vitro and in eight patients with the most commonly employed metallic biliary endoprosthesis. In vitro, the stent produced no tip deflection at 0.6 or 1.5 T. Trace magnetic susceptibility artifact, similar to artifact from a column of air, paralleled the stent. In patients, image degradation was minimal with conventional pulse sequences. Middle-field-strength spin-echo images revealed minimal artifacts indistinguishable from those produced by pneumobilia. 相似文献
33.
34.
Effect of acupuncture-point stimulation on diastolic blood pressure in hypertensive subjects: a preliminary study 总被引:1,自引:0,他引:1
Electrical stimulation of four specific acupuncture points (Liver 3, Stomach 36, Large Intestine 11, and the Groove for Lowering Blood Pressure) was examined in order to determine the effect of this stimulation on diastolic blood pressure in 10 subjects with diastolic hypertension. Subjects were randomly divided into two groups: (1) an Acu-ES group, which received electrical stimulation applied to the four antihypertensive acupuncture points, and (2) a Sham-ES group, which received electrical stimulation applied to non-acupuncture-point areas. A repeated-measures analysis of variance revealed a significant, immediate poststimulation reduction of diastolic blood pressure for the Acu-Es group versus the Sham-ES group. Further studies are needed to determine whether there are other acupuncture points, stimulation characteristics, or modalities that can enhance this treatment effect and whether the treatment effect can last for a clinically significant period of time. 相似文献
35.
High-specificity in-situ hybridization. Methods and application. 总被引:2,自引:0,他引:2
A A Long J Mueller J Andre-Schwartz K J Barrett R Schwartz H Wolfe 《Diagnostic molecular pathology》1992,1(1):45-57
We describe a technique of in-situ hybridization using oligonucleotide probes employing the expression of immunoglobulin VH genes as a model. Optimal conditions for hybridization with the 35S-labeled oligonucleotide probes were established with monoclonal B-cell lines that express VH genes of known nucleic acid sequence. The range of sensitivity and specificity achieved with this technique is documented. Under conditions of high stringency, this method can detect the expression of highly related VH hypervariable regions. 相似文献
36.
The reform of health information systems has been made a priority by health managers, public health specialists and technocrats. While each of these groups has promised major benefits from improvements in information systems, insufficient attention has been paid to the limitations placed upon the theoretical possibilities of information technology by the characteristics of the health system of which the information system is but a part. Managers anticipate improved efficiency and rational allocation of resources, but rational decision making does not automatically follow from improvements in information. Epidemiologists and public health specialists seek more effective and equitable health systems but methodological problems and the expense of many conventional epidemiological approaches continue to limit the usefulness of disease surveillance, programme monitoring and evaluation. Both managers and epidemiologists are confronted with the conflicts which arise in seeking to create locally sensitive information systems within centralised health systems. Technocrats see microcomputers as essential for information systems to be truly effective and as a means of liberating health workers from the drudgery of form filling. However, the rate of organisational evolution in the health system has not kept pace with the rapid development of information technology. There are good prospects for considerable health gain to be wrought from reforms in health information systems but to realise these it is necessary that this process be 'action-led' rather than, as is conventional, 'data-led'. The latter approach sees data as the end in itself; the 'action-led' approach, in contrast, regards information as needs to interventions with a focus on how information will influence decisions. For improvements in information to result in improved health, strategies must be adopted which will ensure that information routinely informs decisions and is seen as a means to the end of improving health. 相似文献
37.
Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model 总被引:3,自引:0,他引:3
David E. Rosow M.D. Dushyant Sahani M.D. Oliver Strobel M.D. Sanjeeva Kalva M.D. Mari Mino-Kenudson M.D. Nagaraj S. Holalkere M.D. Guido Alsfasser M.D. Sanjay Saini M.D. Susanna I. Lee M.D. Peter R. Mueller M.D. Carlos Fernándezdel Castillo M.D. Andrew L. Warshaw M.D. Sarah P. Thayer M.D. Ph.D. 《Journal of gastrointestinal surgery》2005,9(9):1262-1275
Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical
outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography
is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive
but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly
facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately
demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization
of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols.
After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT
angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including
poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findingsd—compared
with pathologic diagnosesd—predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA
holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia.
Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–18,
2005 (oral presentation).
Supported by the Karin Grunebaum Research Fellowship, Harvard Medical School (D.E.R.), the German Research Fellowship, German
Research Foundation STR 690/1-1 (O.S.), and the Phillip H. Meyers Grant from the Society of Gastrointestinal Radiologists
(S.P.T.). 相似文献
38.
Five tests of hand skill. 总被引:5,自引:0,他引:5
M Annett 《Cortex; a journal devoted to the study of the nervous system and behavior》1992,28(4):583-600
Four group tests of hand skill, square marking (SQUARES), dotting between targets (DOTS), line drawing between targets (LINES) and punching holes through targets (HOLES), were given to samples of undergraduates and schoolchildren, most of whom were also tested individually on a peg moving task (PEGS). Findings for PEGS were shown to be comparable to those of previous samples. Each new task was compared with PEGS for a standard measure of hand skill asymmetry (R-L%) using 4 criteria of comparison. For 3 criteria there was good agreement: correlations were statistically significant, hand preference subgroups were similar for rank order and the extent of asymmetry was more strongly associated with left hand scores than with right hand scores. This last finding was true for all of 12 comparisons for differing tests and samples, indicating that the finding is unlikely to be an artefact of score transformations as suggested by Bishop (1990a, 1990b). The fourth criterion of comparison, the distribution of R-L% scores, differed between the tasks. All of the new tasks found larger differences between the hands than PEGS. Whereas the shape of the distribution was unimodal for PEGS, as in previous studies, the distributions for DOTS and HOLES were clearly bimodal. Possible reasons for the larger between hand differences for some tasks are considered. It is suggested that the main difference between PEGS (and also to a lesser extent LINES) in comparison with DOTS and HOLES lies in the demand characteristics of the testing situation. Tasks which merely invite subjects to mark as many targets as possible in a unit of time may underestimate the skill of the nonpreferred hand. 相似文献
39.
Annett Wunder 《MedR Medizinrecht》2007,25(1):21-28
Ohne Zusammenfassung 相似文献
40.
Journal of Neurology - Fatigue is a widespread symptom in numerous neuroimmunological diseases like multiple sclerosis (MS), myasthenia gravis, morbus Behcet, neurosarcoidosis, neuroborreliosis or... 相似文献