首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   24510篇
  免费   1526篇
  国内免费   176篇
耳鼻咽喉   235篇
儿科学   523篇
妇产科学   467篇
基础医学   3655篇
口腔科学   259篇
临床医学   2317篇
内科学   6141篇
皮肤病学   367篇
神经病学   2119篇
特种医学   1071篇
外国民族医学   8篇
外科学   4215篇
综合类   69篇
一般理论   4篇
预防医学   1342篇
眼科学   211篇
药学   1353篇
中国医学   41篇
肿瘤学   1815篇
  2023年   135篇
  2022年   220篇
  2021年   607篇
  2020年   364篇
  2019年   587篇
  2018年   690篇
  2017年   466篇
  2016年   557篇
  2015年   711篇
  2014年   935篇
  2013年   1204篇
  2012年   1913篇
  2011年   1888篇
  2010年   1093篇
  2009年   1100篇
  2008年   1681篇
  2007年   1697篇
  2006年   1657篇
  2005年   1703篇
  2004年   1572篇
  2003年   1480篇
  2002年   1390篇
  2001年   201篇
  2000年   147篇
  1999年   216篇
  1998年   264篇
  1997年   231篇
  1996年   190篇
  1995年   159篇
  1994年   116篇
  1993年   142篇
  1992年   105篇
  1991年   80篇
  1990年   78篇
  1989年   52篇
  1988年   57篇
  1987年   40篇
  1986年   50篇
  1985年   44篇
  1984年   38篇
  1983年   49篇
  1982年   41篇
  1981年   48篇
  1980年   37篇
  1979年   21篇
  1978年   16篇
  1977年   15篇
  1976年   14篇
  1975年   18篇
  1972年   12篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.
Gene therapy is an attractive approach for the treatment of a wide spectrum of liver diseases. Lentiviral vectors allow the stable integration of transgenes into the genome of nondividing differentiated cells including hepatocytes and could provide long-lasting expression of a therapeutic gene. To develop such approaches, preclinical studies in large animal models such as pigs are necessary to evaluate the feasibility and safety of stable lentiviral integration and long-term vector expression. In addition, effective lentivector-mediated gene transfer onto porcine hepatocytes could advance in cell-based therapies for acute liver failure. To investigate this issue, porcine hepatocytes were transduced in suspension immediately after their isolation in University of Wisconsin (UW) solution containing vitamin E. Up to 80% of hepatocytes stably expressed a GFP transgene after a single exposure to lentiviral vector coding for GFP under the control of either liver-specific or ubiquitous promoters. Moreover, porcine hepatocytes cryopreserved in UW solution containing fetal bovine serum, dimethyl sulfoxide, and vitamin E remained highly transducible with lentiviral vector after thawing. When thawed, transduced in suspension, and immediately transplanted into the spleen of immunodeficient mice, ex vivo lentivirally transgene marked xenogeneic hepatocytes were detected in murine liver. We demonstrated that porcine hepatocytes are highly susceptible to lentiviral vector and describe an easy methodology to efficiently, rapidly, and stably introduce transgenes into uncultured porcine hepatocytes.  相似文献   
122.
PURPOSE: To compare the effects of recombinant activated factor VII (rFVIIa) and platelet-rich plasma (PRP) in an experimental model of bleeding and arterial thrombosis. METHODS: The Folts model was used in 60 rabbits. After anesthesia, the carotid artery was exposed and a 75% stenosis was induced. A compression injury of the artery triggered a series of cyclic flow reductions (CFRs). After counting baseline CFRs, animals were assigned randomly to one of four groups (n = 15 in each): control, PRP, rFVIIa and placebo. Control animals received 10 mL.kg(-1) of saline while 10 mL.kg(-1) of a hydroxyethyl starch solution (200,000/6%/0.5) were infused in the three other groups. CFRs were measured again, followed by treatment with PRP, rFVIIa or placebo and by a final measurement of CFRs. At the end of each observation period, an ear immersion bleeding time (BT) was measured and a blood sample was drawn for the evaluation of hematological variables. Microvascular bleeding was evaluated at the end of the experiment in grams of blood shed from liver and spleen sections. Results are presented as median (range). RESULTS: rFVIIa shortened the BT and decreased microvascular bleeding as compared with placebo [60 (35-100) sec vs 110 (50-140) sec, P = 0.0019 and 9 (4-24) g vs 17 (5-28) g, P = 0.002, respectively]. rFVIIa did not increase CFRs [3(0-9) vs |(0-5), P = 0.11]. CONCLUSION: rFVIIa led to a decrease in BT and microvascular bleeding but did not significantly affect arterial thrombosis in rabbits.  相似文献   
123.
124.
To understand the adaptive value of reminiscence, a mediational model of reminiscence was tested in a sample of older adults with mild to moderate depressive symptoms. Using structural equation modeling, we investigated if psychological resources (mastery and meaning in life) mediate the relation between reminiscence (positive: identity construction and problem solving; and negative: bitterness revival and boredom reduction) and psychological distress (depressive symptoms and anxiety symptoms). A total of 202 older Dutch adults living in the community participated in this study. The present study consisted of baseline measurements of a randomized controlled trial that evaluated the effectiveness of a life-review therapy intervention on depression. Results showed that psychological resources fully mediated the relation between negative reminiscence and psychological distress. Specifically, negative reminiscing is related to decreased psychological distress through meaning in life and sense of mastery. The study contributes to current knowledge on the relation between reminiscence and mental health, both empirically and clinically. It helps to increase understanding of how reminiscence is related to psychological distress, especially in depressed older adults, and the relative importance of psychological resources, i.e., mastery and meaning in life. From a clinical perspective, these findings suggest the usefulness of focusing on strengthening psychological resources in therapeutic reminiscence-based strategies for older adults with depressive symptoms.  相似文献   
125.
126.
127.
128.
129.
AIMS: Inappropriate therapy delivered by implantable cardioverter defibrillators (ICDs) remains a challenge. The OPERA registry measured the times to, and studied the determinants of, first appropriate (FAT) and inappropriate (FIT) therapies delivered by single-, dual- and triple-chamber [cardiac resynchronization therapy defibrillator (CRT-D)] ICD. METHODS AND RESULTS: We entered 636 patients (mean age = 62.0 ± 13.5 years; 88% men) in the registry, of whom 251 received single-, 238 dual-, and 147 triple-chamber ICD, for primary (30.5%) or secondary (69.5%) indications. We measured times to FAT and FIT as a function of multiple clinical characteristics, examined the effects of various algorithm components on the likelihood of FAT and FIT delivery, and searched for predictors of FAT and FIT. Over 22.8 ± 8.8 months of observation, 184 patients (28.9%) received FAT and 70 (11.0%) received FIT. Ventricular tachycardia (VT) was the trigger of 88% of FAT, and supraventricular tachycardia was the trigger of 91% of FIT. The median times to FIT (90 days; range 49-258) and FAT (171 days; 50-363) were similar. The rate of FAT was higher (P <0.001) in patients treated for secondary than primary indications, while that of FIT were similar in both groups. Out of 57 analysable FIT, 27 (47.4%) could have been prevented by fine tuning the device programming like the sustained rate duration or the VT discrimination algorithm. CONCLUSIONS: First inappropriate therapy occurred in 11% of 636 ICD recipients followed for ~2 years. Nearly 50% of FIT could have been prevented by improving device programming.  相似文献   
130.
A rehabilitation program including foot sensory stimulation, balance and gait training with limited vision was followed by 30 patients with ataxic neuropathy in order to stimulate multi-sensory compensation in a no-controlled and no-blinded study. Ataxic neuropathy was graded by a pallesthetic score. The evaluation of patients and healthy subjects was performed with clinical tests (Berg Balance Scale, Functional Reach Test and Timed up and Go test) and instrumental tests for balance (force platform) and gait (Locometre). All patients exhibited impairments in balance and gait parameters compared to control group values. A high pallesthetic score correlated with increased sway area when standing with the eyes open on a firm surface. At the end of the training program, significant changes were observed in balance control assessed using the three clinical tests (Wilcoxon test, p < 0.001). A tendency towards a reduction of the Romberg sign was noticed and limited changes were observed after training in instrumental tests for balance and for gait parameters. Age induced some limitations in balance and gait parameters but had no effect on training results. These results show that ataxic patients are impaired in balance and gait but can improve clinical balance parameters following training with a multisensory approach without limitation due to age or degree of sensory impairment. Only limited correlations were noticed between the pallesthetic score and some balance parameters, suggesting that various levels of compensation occur in these patients. The effectiveness of this training program has to be evaluated in the future in a controlled study to ascertain the contribution of the placebo effect in these data.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号