全文获取类型
收费全文 | 118882篇 |
免费 | 6951篇 |
国内免费 | 1582篇 |
专业分类
耳鼻咽喉 | 1578篇 |
儿科学 | 2970篇 |
妇产科学 | 4111篇 |
基础医学 | 18302篇 |
口腔科学 | 3609篇 |
临床医学 | 9281篇 |
内科学 | 21615篇 |
皮肤病学 | 2454篇 |
神经病学 | 8009篇 |
特种医学 | 4021篇 |
外国民族医学 | 3篇 |
外科学 | 16743篇 |
综合类 | 5213篇 |
一般理论 | 34篇 |
预防医学 | 8681篇 |
眼科学 | 2818篇 |
药学 | 10216篇 |
中国医学 | 818篇 |
肿瘤学 | 6939篇 |
出版年
2021年 | 981篇 |
2019年 | 1046篇 |
2018年 | 1613篇 |
2017年 | 1169篇 |
2016年 | 1198篇 |
2015年 | 1443篇 |
2014年 | 1888篇 |
2013年 | 2444篇 |
2012年 | 3544篇 |
2011年 | 3798篇 |
2010年 | 2285篇 |
2009年 | 2048篇 |
2008年 | 3388篇 |
2007年 | 3615篇 |
2006年 | 3597篇 |
2005年 | 3164篇 |
2004年 | 2982篇 |
2003年 | 2776篇 |
2002年 | 2629篇 |
2001年 | 6730篇 |
2000年 | 6923篇 |
1999年 | 5700篇 |
1998年 | 1830篇 |
1997年 | 1377篇 |
1996年 | 935篇 |
1995年 | 864篇 |
1992年 | 3730篇 |
1991年 | 3807篇 |
1990年 | 3551篇 |
1989年 | 3552篇 |
1988年 | 3430篇 |
1987年 | 3277篇 |
1986年 | 3092篇 |
1985年 | 2967篇 |
1984年 | 2049篇 |
1983年 | 1794篇 |
1982年 | 985篇 |
1979年 | 1909篇 |
1978年 | 1184篇 |
1977年 | 986篇 |
1976年 | 918篇 |
1975年 | 1191篇 |
1974年 | 1358篇 |
1973年 | 1413篇 |
1972年 | 1357篇 |
1971年 | 1247篇 |
1970年 | 1137篇 |
1969年 | 1121篇 |
1968年 | 1024篇 |
1967年 | 897篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The involuntary hospitalisation of psychiatric patients continues to be a controversial issue. All patients certified and admitted to Sterkfontein Hospital under Sections 9 and 12 of the Mental Health Act, No. 18 of 1973, over a 4-week period were surveyed. Almost 40% were admitted as urgent certifications. The majority of the patients in the sample were black, single, urban and had either primary or limited high school education. Most patients had been referred from academic/teaching and provincial hospitals. The average duration of hospital stay was 7.2 weeks, with only 1 patient eventually being transferred to a ward for chronic patients within the hospital, which suggests that Sterkfontein Hospital functions largely as an acute psychiatric facility. There was a discrepancy of approximately 30% between the assessments of the certifying and ward doctors, probably as a result of differing uses of terminology. Not only are more community psychiatric services needed, but communication between psychiatry and the other medical disciplines should be improved. 相似文献
82.
83.
84.
G. Wu S. F. Fan Z.-H. Lu R. W. Ledeen S. M. Crain 《Journal of neuroscience research》1995,42(4):493-503
Prolongation of the action potential duration of dorsal root ganglion (DRG) neurons by low (nM) concentrations of opioids occurs through activation of excitatory opioid receptors that are positively coupled via Gs regulatory protein to adenylate cyclase. Previous results suggested GM1 ganglioside to have an essential role in regulating this excitatory response, but not the inhibitory (APD-shortening) response to higher (μM) opioid concentrations. Furthermore, it was proposed that synthesis of GM1 is upregulated by prolonged activation of excitatory opioid receptor functions. To explore this possibility we have utilized cultures of hybrid F11 cells to carry out closely correlated electrophysiological and biochemical analyses of the effects of chronic opioid treatment on a homogeneous population of clonal cells which express many functions characteristic of DRG neurons. We show that chronic opioid exposure of F11 cells does, in fact, result in elevated levels of GM1 as well as cyclic adenosine monophosphate (AMP), concomitant with the onset of opioid excitatory supersensitivity as manifested by naloxone-evoked decreases in voltage-dependent membrane K+ currents. Such elevation of GM1 would be expected to enhance the efficacy of excitatory opioid receptor activation of the Gs/adenylate cyclase/cyclic AMP system, thereby providing a positive feedback mechanism that may account for the remarkable supersensitivity of chronic opioid-treated neurons to the excitatory effects of opioid agonists as well as antagonists. These in vitro findings may provide novel insights into the mechanisms underlying naloxone-precipitated withdrawal syndromes and opioid-induced hyperalgesia after chronic opiatf addiction in vivo. © 1995 Wiley-Liss, Inc. 相似文献
85.
86.
Clinicopathologic correlation of pigmented epiretinal membranes 总被引:1,自引:0,他引:1
G M Cherfan W E Smiddy R G Michels Z de la Cruz C P Wilkinson W R Green 《American journal of ophthalmology》1988,106(5):536-545
We performed clinicopathologic correlation on ten surgically removed pigmented epiretinal membranes causing macular pucker. All cases occurred in eyes with existing retinal holes or tears, including eight cases of macular pucker after previous retinal detachment. These cases probably represented a limited form of proliferative vitreoretinopathy. All membranes contained pigment epithelial cells with polarity, basement membrane, and melanosomes. Cytoplasmic melanin granules accounted for the clinical feature of pigmentation in these eyes. 相似文献
87.
88.
89.
Z. Janczewski L. Bablok A. Smith M. Czaplicki S. Fr⇂cki 《International urology and nephrology》1990,22(2):161-165
Changes in semen parameters are presented for 4708 patients treated for infertility. The largest group comprised patients
with oligoasthenozoospermia of various grades (57.7%). Improvement in the seminal state was noted in 70.3%. The percentage
of achieved normospermia increased proportionally to the initial semen state. Pregnancy rate also increased proportionally
to the initial seminal state.
Among the patients' wives 20.4% conceived: 28.2% of these pregnancies had occurred after having achieved normospermia, while
in 71.8% the seminal states were still below the accepted normal values. 相似文献
90.
We report a series of 33 consecutive hospitalized geriatric diabetic patients who were referred for evaluation of diabetic nephropathy, defined as proteinuria greater than or equal to 1 g/d (1,000 mg/24 h) or a serum creatinine concentration greater than or equal to 177 mumol/d (greater than or equal to 2 mg/dL). The study population was 60 years old or older (mean age, 68 +/- 6 years), was comprised mainly of women (24 of 33, 72.7%), and was predominantly black (25 of 33, 75.8%). All patients had type II diabetes. A family history of diabetes in parent or sibling was elicited in 24 (72.7%) patients. There were eight patients undergoing maintenance hemodialysis and 25 with less severe nephropathy (mean proteinuria, 2.7 g/d [2,700 mg/24 h]; mean creatinine clearance, 0.57 mL-s [34 mL/min]). Cardiac disorders were noted in the majority of patients: congestive failure in 20 (60.6%), myocardial infarction in eight (24.2%), and active angina in five (15.2%). Other comorbid diseases were present in both hemodialysis patients and the subset of nondialyzed azotemic-proteinuric patients, and consisted of peripheral neuropathy in 31 (93.9%), gastroparesis in 16 (48.5%), retinopathy in 28 (84.8%), and legal blindness in 11 (33%). We conclude that geriatric diabetic nephropathy in type II diabetes is similar in presentation and severity of comorbid extrarenal complications to the syndrome described in younger adults. This inference must be tempered by both the small size and the limitation imposed by the demographics of the study population, which is predominantly composed of black patients receiving treatment at inner city hospitals. 相似文献