全文获取类型
收费全文 | 3603篇 |
免费 | 244篇 |
国内免费 | 63篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 176篇 |
妇产科学 | 47篇 |
基础医学 | 394篇 |
口腔科学 | 112篇 |
临床医学 | 356篇 |
内科学 | 638篇 |
皮肤病学 | 61篇 |
神经病学 | 349篇 |
特种医学 | 412篇 |
外国民族医学 | 3篇 |
外科学 | 243篇 |
综合类 | 99篇 |
一般理论 | 1篇 |
预防医学 | 270篇 |
眼科学 | 102篇 |
药学 | 265篇 |
肿瘤学 | 369篇 |
出版年
2021年 | 26篇 |
2019年 | 21篇 |
2018年 | 36篇 |
2017年 | 24篇 |
2016年 | 36篇 |
2015年 | 39篇 |
2014年 | 52篇 |
2013年 | 80篇 |
2012年 | 84篇 |
2011年 | 103篇 |
2010年 | 76篇 |
2009年 | 80篇 |
2008年 | 150篇 |
2007年 | 172篇 |
2006年 | 165篇 |
2005年 | 160篇 |
2004年 | 128篇 |
2003年 | 135篇 |
2002年 | 114篇 |
2001年 | 115篇 |
2000年 | 114篇 |
1999年 | 107篇 |
1998年 | 83篇 |
1997年 | 93篇 |
1996年 | 79篇 |
1995年 | 77篇 |
1994年 | 50篇 |
1993年 | 72篇 |
1992年 | 94篇 |
1991年 | 93篇 |
1990年 | 97篇 |
1989年 | 122篇 |
1988年 | 92篇 |
1987年 | 86篇 |
1986年 | 79篇 |
1985年 | 77篇 |
1984年 | 75篇 |
1983年 | 53篇 |
1982年 | 42篇 |
1981年 | 41篇 |
1980年 | 54篇 |
1979年 | 67篇 |
1978年 | 40篇 |
1977年 | 33篇 |
1976年 | 28篇 |
1975年 | 30篇 |
1973年 | 26篇 |
1972年 | 23篇 |
1970年 | 20篇 |
1969年 | 27篇 |
排序方式: 共有3910条查询结果,搜索用时 156 毫秒
1.
2.
Double-blind, placebo-controlled comparison of clonazepam and alprazolam for panic disorder 总被引:1,自引:0,他引:1
G E Tesar J F Rosenbaum M H Pollack M W Otto G S Sachs J B Herman L S Cohen S A Spier 《The Journal of clinical psychiatry》1991,52(2):69-76
To test the reported antipanic efficacy of clonazepam, the authors randomized 72 subjects with panic disorder to 6 weeks of treatment with either alprazolam, clonazepam, or placebo. Endpoint analysis demonstrated a significant beneficial effect of both active treatments, but not placebo treatment, on the frequency of panic attacks, overall phobia ratings, and the extent of disability. Comparison of the two active treatments revealed no significant differences and no consistent tendency for one agent to be favored over another, although power to detect small differences was limited. Sedation and ataxia were the most common side effects reported, but these effects were mild and transient and did not interfere with treatment outcome. The results of this double-blind, placebo-controlled trial are consistent with previous reports of clonazepam's antipanic efficacy. 相似文献
3.
4.
A retrospective analysis of 1,259 patients injured in all-terrain vehicle accidents over a 2-year period was performed. All patients presented to the same community hospital Emergency Department, located near a major desert off-road vehicle recreational area. The patients were characterized by demographics and Injury Severity Scores. There were 2,149 recorded injuries. Mean ISS +/- standard deviation for all patients was 5.07 +/- 4.93; among patients admitted for inpatient care, 9.83 +/- 6.46. Injury Severity Scores were independent of vehicle type (two, three, or four wheels). In this setting, injuries sustained by children were not disproportionately more severe than those sustained by adults. Where documented, alcohol use was associated with higher ISS, and the use of helmets was associated with less severe head and facial injuries. The most common diagnoses in this series were integumental injuries and fractures, frequently involving the face and extremities. 相似文献
5.
Can Electrocardiographic Criteria Predict Adverse Cardiac Events and Positive Cardiac Markers? 总被引:5,自引:0,他引:5
Andra L. Blomkalns MD Christopher J. Lindsell PhD Abhinav Chandra MD Mary E. Osterlund MD W. Brian Gibler MD Charles V. Pollack MS MD Brian R. Tiffany MD PhD Judd E. Hollander MD James W. Hoekstra MD 《Academic emergency medicine》2003,10(3):205-210
OBJECTIVES: To determine electrocardiogram (ECG) predictors of positive cardiac markers and short-term adverse cardiac events in an undifferentiated chest pain population presenting to emergency departments (EDs). The authors hypothesized that specific ECG findings, other than those previously identified in higher-risk populations, would be predictive of cardiac outcomes and positive cardiac markers. METHODS: This study used data from a prospectively collected, retrospectively analyzed Internet-based data registry of undifferentiated chest pain patients (i*trACS). Logistic regression modeling was performed to determine the ECG findings that were predictive of 1) positive cardiac markers and 2) short-term adverse cardiac events. RESULTS: ST-segment elevation (STE), ST-segment depression (STD), pathological Q-waves (PQW), and T-wave inversion were associated with increased odds of percutaneous coronary intervention or catheterization, myocardial infarction, or coronary artery bypass grafting. The odds of creatine kinase-MB (CK-MB) measuring positive were increased if STE, STD, or PQW were present [odds ratio (OR) 2.495, 2.582, and 1.295, respectively]. A right bundle branch block tended to decrease the odds of CK-MB measuring positive (OR 0.658). A similar pattern of results was observed for troponin I (OR 3.608 for STE, 3.72 for STD, 1.538 for PQW). Troponin T showed an increased odds of measuring positive if any of STE, STD, left bundle branch block, or T-wave inversion were evident (OR 2.313, 2.816, 1.80, and 1.449, respectively). CONCLUSIONS: Initial ECG criteria can be used to predict short-term cardiac outcomes and positive cardiac markers. These findings can be important aids in the risk-stratification and aggressive treatment regimens of chest pain patients presenting to EDs. 相似文献
6.
7.
INVOLVEMENT OF NON-NMDA AND NMDA RECEPTORS IN GLUTAMATE-INDUCED PRESSOR OR DEPRESSOR RESPONSES OF THE PONS AND MEDULLA 总被引:1,自引:0,他引:1
SY Chen WC Wu CJ Tseng JS Kuo CY Chai 《Clinical and experimental pharmacology & physiology》1997,24(1):46-56
1. Fifty-five intact and six baroreceptor denervated and vagotomized cats of either sex were anaesthetized intraperito-neally with urethane (400 mg/kg) and a-chloralose (40 mg/kg). Responses of the systemic arterial pressure (SAP), mean SAP (MSAP) and sympathetic vertebral nerve (VNA) and renal nerve activities (RNA) were recorded. 2. In intact animals, monosodium L-glutamate (Glu, 0.1 mol/L, 50 nL) was microinjected into pressor areas of the locus coeruleus (LC), gigantocellular tegmental field (GTF), rostral ventrolateral medulla (RVLM) and dorsomedial medulla (DM), and the depressor areas of caudal ventrolateral medulla (CVLM). The induced actions were compared before and after microinjection of either glutamate antagonists, glutamate diethylester (GDEE, 0.5 mol/L, 50–100nL), a competitive AMPA receptor blocker, or 2-amino-5-phosphonovaleric acid (D-AP5, 0.025 mol/L, 50–100 nL), a competitive N-methyl-D-aspartate (NMDA) receptor blocker. GDEE completely blocked the increases of SAP and VNA elicited from all pressor areas. D-AP5 only partially blocked the pressor but slightly blocked VNA and RNA responses from LC, GTF and DM, particularly those from RVLM. Neither GDEE nor D-AP5 blocked the depressor responses of SAP and two nerve activities elicited from CVLM. 3. In baroreceptor denervated animals, NMDA (2 mmol/L, 50–100 nL) and AMPA (0.2 mmol/L, 50–100 nL) were micro-injected into the same pressor areas of GTF, RVLM and DM and the depressor area of CVLM responsive to Glu activation (0.1 mol/L, 30 nL). In RVLM, DM and CVLM, the results of either NMDA or AMPA were similar to those induced by Glu. However, in GTF, microinjection of either NMDA or AMPA did not induce similar responses to Glu. This suggests that the nature of GTF may differ from RVLM and DM. 4. The above results suggest that the Glu-induced pressor responses from LC, GTF, DM and especially RVLM, are primarily mediated through AMPA receptors. The Glu-induced depressor responses from CVLM may not be predominantly mediated by either AMPA or NMDA receptors. 5. In both baroreceptor-intact and -denervated cats stimulation of the pressor areas often produced an increase of VNA and a decrease of RNA, while in the depressor CVLM decreased both VNA and RNA. The VNA, but not RNA were positively correlated with the pressor responses, while both VNA and RNA were positively correlated with the depressor responses. This may suggest that neurons of the sympathetic vertebral and renal nerves are topographically organized in the brain. 相似文献
8.
Neurofibromatosis is a relatively common autosomal dominant disorder with variable penetrance. The disorder usually presents in childhood. Hallmarks of type 1 neurofibromatosis are café-au-lait macules and neurofibromas. Neurologic complications include mental retardation, learning disabilities and seizures. Tumors of the eighth cranial nerve, as well as other intracranial and spinal neoplasms, are the typical lesions in type 2 neurofibromatosis. Both forms of neurofibromatosis have a highly variable course and may result in progressive neurologic deterioration, disfigurement and impingement syndromes. In the 50 percent of cases that represent new mutations, diagnosis may be delayed if the physician is not familiar with the salient features of the disorder. Thorough initial evaluation, genetic counseling and close follow-up are important aspects of management. 相似文献
9.
Hillmann JS; Mesgarzadeh M; Revesz G; Bonakdarpour A; Clancy M; Betz RR 《Radiology》1987,165(3):769-773
Proximal femoral focal deficiency, an uncommon congenital anomaly, necessitates early radiologic classification for surgical planning and treatment. Objective radiographic criteria, including femoral length index, acetabular depth index, acetabular angle index, and shape of the proximal femur were determined in 49 patients before cartilaginous ossification of the femoral capital epiphysis; final classification was based on follow-up radiographs or findings at arthrography or surgery. These parameters were analyzed to determine the accuracy and contributions of each in classification. Correct classification into one of three groups was possible in 86% of cases with use of three of the parameters: femoral length index, acetabular depth index, and shape of the proximal femur. The acetabular angle was found to contribute insignificantly to classification. Magnetic resonance imaging, used in only one case, depicted the nonossified cartilaginous femoral capital epiphysis, thus obviating the need for invasive diagnostic procedures and facilitating early classification. 相似文献
10.