全文获取类型
收费全文 | 8672篇 |
免费 | 511篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 63篇 |
儿科学 | 247篇 |
妇产科学 | 199篇 |
基础医学 | 1353篇 |
口腔科学 | 487篇 |
临床医学 | 982篇 |
内科学 | 1536篇 |
皮肤病学 | 161篇 |
神经病学 | 778篇 |
特种医学 | 234篇 |
外国民族医学 | 2篇 |
外科学 | 1008篇 |
综合类 | 60篇 |
一般理论 | 3篇 |
预防医学 | 744篇 |
眼科学 | 84篇 |
药学 | 693篇 |
中国医学 | 23篇 |
肿瘤学 | 550篇 |
出版年
2022年 | 72篇 |
2021年 | 119篇 |
2020年 | 95篇 |
2019年 | 145篇 |
2018年 | 151篇 |
2017年 | 130篇 |
2016年 | 127篇 |
2015年 | 117篇 |
2014年 | 199篇 |
2013年 | 325篇 |
2012年 | 406篇 |
2011年 | 418篇 |
2010年 | 224篇 |
2009年 | 233篇 |
2008年 | 385篇 |
2007年 | 340篇 |
2006年 | 363篇 |
2005年 | 361篇 |
2004年 | 315篇 |
2003年 | 264篇 |
2002年 | 291篇 |
2001年 | 248篇 |
2000年 | 276篇 |
1999年 | 257篇 |
1998年 | 93篇 |
1997年 | 100篇 |
1996年 | 65篇 |
1995年 | 90篇 |
1994年 | 68篇 |
1993年 | 71篇 |
1992年 | 186篇 |
1991年 | 204篇 |
1990年 | 191篇 |
1989年 | 181篇 |
1988年 | 188篇 |
1987年 | 189篇 |
1986年 | 183篇 |
1985年 | 179篇 |
1984年 | 109篇 |
1983年 | 121篇 |
1982年 | 81篇 |
1981年 | 78篇 |
1980年 | 61篇 |
1979年 | 106篇 |
1978年 | 90篇 |
1977年 | 82篇 |
1976年 | 57篇 |
1975年 | 60篇 |
1974年 | 59篇 |
1973年 | 53篇 |
排序方式: 共有9207条查询结果,搜索用时 15 毫秒
91.
The effect of imipramine and lithium on "learned helplessness" and acetylcholinesterase in rat brain
M Geoffroy K Tvede A V Christensen J S Schou 《Pharmacology, biochemistry, and behavior》1991,38(1):93-97
The effect of short- and long-term treatment with imipramine and lithium on shock stress-induced escape failures in a shuttlebox (the "learned helplessness" model of depression) was investigated in rats. Acetylcholinesterase (AChE) activity was measured in the frontal cortex, hippocampus and striatum after the shuttlebox test. Imipramine was found to normalize escape behavior, whereas lithium further aggravated escape behavior. No correlation was found between escape behavior and AChE activity in the three brain areas investigated. However, a significant decrease in AChE activity in striatum was found in rats exposed either to shock stress and no drug treatment or to drug treatment and no shock stress. In rats exposed to the combination of shock stress and drug (imipramine or lithium), a slight or no decrease of AChE activity occurred. Exposure to shock stress alone produced no changes in AChE activity in the hippocampus and frontal cortex. In conclusion, lithium did not have an antidepressant effect on "learned helplessness" and AChE activity was not correlated to escape behavior. However, both imipramine and lithium normalized the decreased level of AChE activity in striatum in rats exposed to shock stress. 相似文献
92.
In the present study, we evaluated the relationship between 1. the volume and rate of dialysis outflow and subsequent inflow, 2. the patient's impression of the location of the catheter tip and 3. the stability of the catheter tip location. Thirteen patients were studied on 2 random occasions (periods 1 and 2). Inflow (L/min) was significantly faster than outflow (p less than 0.05). No catheter tips were located in the far upper part of the abdomen. Outflow with the catheter tip located in the middle part of the abdomen was significantly lower than with the tip located in the inferior quadrants (p less than 0.02). Two patients were able to feel the catheter tip at Period 1, and 4 at Period 2, but only 1 patient was able to state the exact location identical to fluoroscopy. Ninety-two percent of the fluoroscopic evaluations showed catheter tips located in the same anatomical regions in upright as well as supine positions. If vertical "neighbour" anatomical regions were included in the evaluation of the catheter tip migrations, all catheter tips were located at the same or the vertical "neighbour" region in the 2 study periods. 相似文献
93.
94.
BACKGROUND: The causes of albuminuria in patients with type 2 diabetes are heterogeneous and are scantily investigated, particularly if the patient has a lack of diabetic retinopathy. Therefore, we evaluated the structural background of albuminuria in a large consecutive group of Caucasian patients with type 2 diabetes without retinopathy. METHODS: Three hundred forty-seven consecutive patients with type 2 diabetes with persistent albuminuria (>300 mg/24 h) were recorded. Fundus photo (80%) and ophthalmoscopy were performed. Ninety-three (27%) had no retinopathy, and a kidney biopsy was performed in 52 (56%) of these patients. An insufficient tissue sample was obtained in one patient. The biopsies were evaluated by three masked nephropathologists. RESULTS: The biopsies revealed diabetic glomerulopathy in 69% of the patients (28 males and 7 females), while the remaining 31% (95% CI, 18 to 44) had either nondiabetic glomerulopathies such as glomerulonephritis (N = 7, 6 males and 1 female, 13%) or normal glomerular structure (N = 9, 7 males and 2 females, 18%). No significant differences in sex, age (56 +/- 8 vs. 53 +/- 10 years, mean SD), body mass index (30 +/- 4 vs. 31 +/- 8 kg/m2), known duration of diabetes (6 +/- 6 vs. 4 +/- 3 years), GFR (95 +/- 29 vs. 89 +/- 31 mL/min/1.73 m2), albuminuria (1304 +/- 169 to 4731 vs. 1050 +/- 181 to 5176 mg/24 hours), blood pressure (150/87 +/- 16/9 vs. 145/89 +/- 16/9 mm Hg), prevalence of hypertension (89 vs. 100%), hemoglobin A1c (8.2 +/- 1.6% vs. 9.0 +/- 2.5%), and serum total cholesterol (7.1 +/- 2.4 vs. 6.3 +/- 1.6 mmol/L) were found between patients with and without diabetic glomerulopathy. CONCLUSIONS: Albuminuric patients with type 2 diabetes without diabetic retinopathy have a prevalence of biopsies with normal glomerular structure or nondiabetic kidney diseases of approximately 30%. A separation between diabetic and nondiabetic glomerular lesions was not possible based on demographic, clinical, or laboratory data. Consequently, such patients may require further evaluation, including a kidney biopsy. 相似文献
95.
Gonzales AJ; Christensen JG; Preston RJ; Goldsworthy TL; Tlsty TD; Fox TR 《Carcinogenesis》1998,19(7):1173-1183
96.
Clinical use of the self-expanding metallic stent in the management of colorectal cancer 总被引:2,自引:0,他引:2
Liberman H Adams DR Blatchford GJ Ternent CA Christensen MA Thorson AG 《American journal of surgery》2000,180(6):133-11; discussion 412
PURPOSE: This report describes our experience with the use of self-expanding metallic stents (SEMS) in the management of obstructing colorectal cancer. METHODS: A retrospective chart review of all patients undergoing placement of SEMS between May 1997 and January 2000 was performed. RESULTS: Insertion of SEMS was attempted in 12 patients. Successful stent placement was achieved in 10 of the 12 patients. The locations of lesions were hepatic flexure (2), splenic flexure (1), left colon (1), sigmoid colon (4) and rectum (4). The intended uses of SEMS were for palliation in 3 patients and as a bridge to elective surgery in 9. In the latter group, SEMS placement allowed for preoperative bowel preparation in 4 patients and administration of neoadjuvant therapy prior to elective surgery in 2 patients. One patient died prior to definitive surgery. Stent placement was unsuccessful in 2 patients. Three SEMS-related complications occurred; 1 stent migrated and 1 stent obstructed secondary to tumor ingrowth. One patient died 13 days after stent placement and colonic decompression. CONCLUSION: SEMS represent a useful tool in the management of obstructing colorectal neoplasms. As a bridge to surgery, SEMS provide time for a complete preoperative evaluation and a mechanical bowel preparation and may obviate the need for fecal diversion or on-table lavage. It may also allow for time to administer neoadjuvant therapy when indicated. As a palliative measure, SEMS can eliminate the need for an operation. 相似文献
97.
Janet Li Paul Roche Jenean Spencer Ivan Bastian Amanda Christensen Mark Hurwitz Anastasios Konstantinos Vicki Krause Moira McKinnon Avner Misrachi Graham Tallis Justin Waring 《Communicable diseases intelligence》2004,28(4):464-473
The National Notifiable Disease Surveillance System (NNDSS) received 982 tuberculosis (TB) notifications in 2003, of which 947 were new cases, 33 were relapses and two were cases with unknown history. The incidence of TB in Australia has remained at a stable rate since 1985 and was 4.9 cases per 100,000 population in 2003. The high-incidence groups remain people born overseas and Indigenous Australians at 19.9 and 8.7 cases per 100,000 population, respectively. By contrast the incidence in non-Indigenous Australians was 0.9 per 100,000. Comparison of the 2003 TB notification data against the performance indicators set by National Tuberculosis Advisory Committee highlights that enhanced TB control measures should be considered among these high-risk groups. 相似文献
98.
99.
Jorm AF Christensen H Medway J Korten AE Jacomb PA Rodgers B 《Social psychiatry and psychiatric epidemiology》2000,35(5):211-219
Background: Previous research has found that there are major differences between public and professional beliefs about the helpfulness
of interventions for depression. The public appear to be guided by general belief systems about the helpfulness of medical,
psychological and lifestyle interventions rather than by specific knowledge about what interventions are effective for depression.
The present paper examines the effect that experiencing depression and receiving treatment might have on these beliefs. Method: The study involved a postal survey of 3109 adults from a region of New South Wales, Australia. Respondents were presented
with a vignette describing a person with depression. They were asked to rate the likely helpfulness of various types of professional
and non-professional help and of pharmacological and non-pharmacological interventions for the person described in the vignette.
Respondents also completed the Goldberg Depression Scale and were asked whether they had ever had an episode of depression
and whether they had seen a counsellor or a doctor for it at the time. Structural equation modelling was used to investigate
the associations of history of depression and professional help-seeking with belief systems. Results: A three-factor model was found to fit the helpfulness ratings, with factors reflecting beliefs in medical, psychological
and lifestyle interventions. People who had sought help for depression were less likely to believe in the helpfulness of lifestyle
interventions and more likely to believe in medical interventions. As well as these general associations with belief systems,
having sought help for depression had a number of specific associations with beliefs. Controlling for general belief systems,
those who had sought help were more likely to rate antidepressants, holidays, massage and new recreational pursuits as helpful,
and were less likely to rate ECT and family as helpful. Those who had a history of depression but had not sought help were
more likely to rate counselling as helpful, and less likely to rate family as helpful. Those with current depressive symptoms
were less likely to rate telephone counselling, family and friends as helpful. Conclusion: Having sought help for depression is associated with general belief systems about the helpfulness of lifestyle and medical
interventions and also has some associations with specific beliefs that may reflect experiences with treatment (e.g. the helpfulness
of antidepressants). Those currently depressed or with a history of depression are less likely to regard family as helpful,
possibly due to poorer social support. Generally speaking, having sought help is associated with beliefs closer to those of
professionals.
Accepted: 31 January 2000 相似文献
100.
Mynster T Christensen IJ Moesgaard F Nielsen HJ 《The British journal of surgery》2000,87(11):1553-1562
BACKGROUND: The frequency of postoperative infectious complications is significantly increased in patients with colorectal cancer receiving perioperative blood transfusion. It is still debated, however, whether perioperative blood transfusion alters the incidence of disease recurrence or otherwise affects the prognosis. METHODS: Patient risk variables, variables related to operation technique, blood transfusion and the development of infectious complications were recorded prospectively in 740 patients undergoing elective resection for primary colorectal cancer. Endpoints were overall survival (n = 740) and time to diagnosis of recurrent disease in the subgroup of patients operated on with curative intention (n = 532). The patients were analysed in four groups divided with respect to administration or not of perioperative blood transfusion and development or non-development of postoperative infectious complications. RESULTS: Overall, 19 per cent of 288 non-transfused and 31 per cent of 452 transfused patients developed postoperative infectious complications (P< 0.001). The median observation period was 6.8 (range 5.4-7.9) years. In a multivariate analysis, risk of death was significantly increased among patients developing infection after transfusion (n = 142) compared with patients receiving neither blood transfusion nor developing infection (n = 234): hazard ratio 1.38 (95 per cent confidence interval (c.i.) 1.05-1.81). Overall survival of patients receiving blood transfusion without subsequent infection (n = 310) and patients developing infection without preceding transfusion (n = 54) was not significantly decreased. In an analysis of disease recurrence the combination of blood transfusion and subsequent development of infection (hazard ratio 1.79 (95 per cent c.i. 1.13-2.82)), localization of cancer in the rectum and Dukes classification were independent risk factors. CONCLUSION: Blood transfusion per se may not be a risk factor for poor prognosis after colorectal cancer surgery. However, the combination of perioperative blood transfusion and subsequent development of postoperative infectious complications may be associated with a poor prognosis. 相似文献