全文获取类型
收费全文 | 3460篇 |
免费 | 280篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 85篇 |
妇产科学 | 144篇 |
基础医学 | 542篇 |
口腔科学 | 61篇 |
临床医学 | 423篇 |
内科学 | 731篇 |
皮肤病学 | 127篇 |
神经病学 | 250篇 |
特种医学 | 219篇 |
外科学 | 294篇 |
综合类 | 76篇 |
预防医学 | 168篇 |
眼科学 | 76篇 |
药学 | 246篇 |
中国医学 | 15篇 |
肿瘤学 | 271篇 |
出版年
2023年 | 20篇 |
2022年 | 32篇 |
2021年 | 91篇 |
2020年 | 57篇 |
2019年 | 85篇 |
2018年 | 102篇 |
2017年 | 91篇 |
2016年 | 82篇 |
2015年 | 127篇 |
2014年 | 148篇 |
2013年 | 203篇 |
2012年 | 243篇 |
2011年 | 260篇 |
2010年 | 182篇 |
2009年 | 166篇 |
2008年 | 220篇 |
2007年 | 216篇 |
2006年 | 182篇 |
2005年 | 159篇 |
2004年 | 131篇 |
2003年 | 115篇 |
2002年 | 98篇 |
2001年 | 79篇 |
2000年 | 43篇 |
1999年 | 70篇 |
1998年 | 74篇 |
1997年 | 64篇 |
1996年 | 34篇 |
1995年 | 29篇 |
1994年 | 26篇 |
1993年 | 18篇 |
1992年 | 14篇 |
1991年 | 25篇 |
1990年 | 28篇 |
1989年 | 25篇 |
1988年 | 40篇 |
1987年 | 29篇 |
1986年 | 27篇 |
1985年 | 20篇 |
1984年 | 25篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1979年 | 11篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 9篇 |
1974年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有3777条查询结果,搜索用时 15 毫秒
981.
982.
983.
US-guided biopsy of neck masses in postoperative management of patients with thyroid cancer 总被引:6,自引:0,他引:6
High-frequency (10-MHz) sonography demonstrated a cervical mass or lymphadenopathy, or both, during postoperative follow-up of 52 patients who had undergone surgery for thyroid cancer. Percutaneous biopsy with ultrasonographic (US) guidance was performed in all 52 masses, 44 of which were nonpalpable. Malignant cells were obtained in 29 biopsies, and the results of 20 biopsies were negative, yielding benign lymphocytes only. Results in three biopsies were nondiagnostic due to hypocellular specimens. Therefore, 94% of biopsy results (49) of 52) were confidently assigned as either positive (56%) or negative (38%) for malignancy. There were no complications. High-frequency sonography can demonstrate clinically occult thyroid bed tumor recurrence and lymph node metastases. US-guided biopsy is an accurate and safe technique to confirm or exclude malignancy in patients at high risk of recurrence of thyroid cancer. 相似文献
984.
Juan CJ Huang GS Hsueh CJ Lee WH Hsu HH Shen HJ Chin SC Hsiao HS 《Skeletal radiology》2000,29(1):49-53
The Magnetic Resonance Imaging (MRI) appearances of primary osseous hemangiopericytoma (HPC) have been rarely described. We
report on a 46-year-old Chinese man with primary osseous HPC of the right tibia. The characteristic vascular distribution
of this tumor, presenting with a ”spoke-wheel” appearance on MR images and with angiographic correlation, is described. Although
not pathognomonic, this MR appearance may be an important finding in suggesting the diagnosis of osseous HPC.
Received: 3 March 1999 Revision requested: 26 April 1999 Revision received: 13 September 1999 Accepted: 15 September 1999 相似文献
985.
986.
987.
Non-evidence-based policy: How effective is China's new cooperative medical scheme in reducing medical impoverishment? 总被引:1,自引:0,他引:1
In recent years, many lower to middle income countries have looked to insurance as a means to protect their populations from medical impoverishment. In 2003, the Chinese government initiated the New Cooperative Medical System (NCMS), a government-run voluntary insurance program for its rural population. The prevailing model of NCMS combines medical savings accounts with high-deductible catastrophic hospital insurance (MSA/Catastrophic). To assess the effectiveness of this approach in reducing medical impoverishment, we used household survey data from 2006 linked to claims records of health expenditures to simulate the effect of MSA/Catastrophic on reducing the share of individuals falling below the poverty line (headcount), and the amount by which household resources fall short of the poverty line (poverty gap) due to medical expenses. We compared the effects of MSA/Catastrophic to Rural Mutual Health Care (RMHC), an experimental model that provides first dollar coverage for primary care, hospital services and drugs with a similar premium but a lower ceiling. Our results show that RMHC is more effective at reducing medical impoverishment than NCMS. Under the internationally accepted poverty line of US$1.08 per person per day, the MSA/Catastrophic models would reduce the poverty headcount by 3.5–3.9% and the average poverty gap by 11.8–16.4%, compared with reductions of 6.1–6.8% and 15–18.5% under the RMHC model. The primary reason for this is that NCMS does not address a major cause of medical impoverishment: expensive outpatient services for chronic conditions. As such, health policymakers need first to examine the disease profile and health expenditure pattern of a population before they can direct resources to where they will be most effective. As chronic diseases impose a growing share of the burden on the population in developing countries, it is not necessarily true that insurance coverage focusing on expensive hospital care alone is the most effective at providing financial risk protection. 相似文献
988.
Effects of Bak Foong Pills and Menoease Pills on white blood cell distribution in old age female rats 总被引:1,自引:0,他引:1
Ho AL Gou YL Rowlands DK Chung YW Chan HC 《Biological & pharmaceutical bulletin》2003,26(12):1748-1753
This study examined the effects of Bak Foong Pills (BFP) and the new BFP-derived post-menopause formula, Menoease Pills (MBFP), on the distribution of peripheral white blood cells (WBC) between BFP/MBFP-treated and non-treated rats. Eighteen months old female SD rats were used to mimic post-menopausal and old age animal models. The percentage distribution of lymphocytes, monocytes and granulocytes were measured using flow cytometry with and without treatments of BFP or MBFP. Results showed that WBC distribution in old age rats were significantly different from that of adult rats, suggesting that as the animal aged, their WBC distributions were altered. Old age rats were observed to have much lower percentages of lymphocytes, but higher percentages of granulocytes when compared to the adult rats, indicating possible attenuated immunity. Following treatment with BFP or MBFP, WBC populations were found to be redistributed back into the ranges observed in adult animals. Furthermore, MBFP, was found to alter WBC distribution in a dose-dependent manner. When compared to estrogen (E(2)), a well documented regulator of immune function, results showed that MBFP was able to show significantly greater effects on WBC redistribution compared to E(2). However, in ovariectomised (ovx) old age rats, neither MBFP nor E(2) treated groups showed any changes in WBC redistribution. These results indicate that MBFP may share similarities to E(2). Indeed, the effect of MBFP and E(2) seems to require intact ovaries, which are believed to be necessary for the modulation of WBC distributions and immune functions. Overall, our findings suggest that BFP and MBFP may be able to regulate WBC population in old age female rats, and thus, indicate their potential role on improving the attenuated immunity evident in post-menopausal and elderly women. 相似文献
989.
Previous animal studies have defined the ability to remember the details of what, where, and when of an event as an episodic-like memory to be used to model episodic memory in humans. Numerous findings indicate that the hippocampal-frontal cortical circuitry plays a major part in its neural mechanism. Researchers have intensively studied roles of diverse hippocampus sub-regions using animal models. By contrast, the impact of prefrontal cortex lesions on episodic-like memory in animals is still unknown. Here we show that Wistar rats with bilateral medial prefrontal cortex lesions failed to use the temporal-contextual information to retrieve memory of a fear-conditioning event, indicating impairments in their episodic-like memory. Subsequent experiments excluded alternative interpretations that the manipulation impaired the fear-conditioning per se, or interfered with the sensory preconditioning process. We concluded that damages in this area might impair temporal information processing, or interfere with integrating temporal and contextual elements of fear-conditioning events to form a conjunctive entity. These findings can help understand how the medial prefrontal cortex contributes to episodic-like memory. 相似文献
990.
Homodimeric tacrine congeners as acetylcholinesterase inhibitors 总被引:3,自引:0,他引:3
In the search for highly selective and potent derivatives of tacrine (1a), a number of homodimeric tacrine congeners were synthesized and conducted for their effects on rat acetylcholinesterase (AChE) and human butyrylcholinesterase (BChE) inhibitions. Heptylene-linked bis-(6-chloro)tacrine (3h) was found up to 3000- and 3-fold more potent in inhibiting rat AChE than tacrine and the unsubstituted bis-tacrine 3b, respectively. Changes in the size of the carbocyclic ring of the dimeric tacrine reduced both the selectivity and the potency of AChE inhibition as compared to 3b. Inserting an aza into the tacrine nucleus as the desired isosteres 3j-m resulted in moderate potency but tended to be detrimental to selectivity. The pronounced enhancement of AChE inhibition potency and AChE/BChE selectivity was achieved with incorporation of a halogen at the 6-position of homodimeric tacrines. The assay results of 3a-m also provided evidence that the 7-methylene tether tended to be optimal to AChE inhibition potency. 相似文献