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   12177篇
  免费   579篇
  国内免费   83篇
耳鼻咽喉   104篇
儿科学   185篇
妇产科学   143篇
基础医学   1468篇
口腔科学   363篇
临床医学   861篇
内科学   3050篇
皮肤病学   290篇
神经病学   1081篇
特种医学   498篇
外科学   2081篇
综合类   67篇
一般理论   1篇
预防医学   385篇
眼科学   287篇
药学   830篇
中国医学   35篇
肿瘤学   1110篇
  2022年   125篇
  2021年   220篇
  2020年   127篇
  2019年   168篇
  2018年   216篇
  2017年   191篇
  2016年   247篇
  2015年   224篇
  2014年   279篇
  2013年   319篇
  2012年   545篇
  2011年   645篇
  2010年   389篇
  2009年   295篇
  2008年   526篇
  2007年   608篇
  2006年   593篇
  2005年   582篇
  2004年   569篇
  2003年   572篇
  2002年   545篇
  2001年   426篇
  2000年   352篇
  1999年   369篇
  1998年   152篇
  1997年   131篇
  1996年   128篇
  1995年   95篇
  1994年   83篇
  1993年   100篇
  1992年   287篇
  1991年   218篇
  1990年   193篇
  1989年   232篇
  1988年   187篇
  1987年   225篇
  1986年   192篇
  1985年   183篇
  1984年   137篇
  1983年   114篇
  1979年   119篇
  1978年   58篇
  1975年   57篇
  1974年   68篇
  1973年   53篇
  1972年   55篇
  1970年   73篇
  1969年   53篇
  1968年   64篇
  1967年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Clinical reports describe an increased incidence of severe enterocolitis in infants with total colonic aganglionosis (TCA) following the Martin extended Duhamel procedure using the entire aganglionic colon. This study evaluates the efficacy of this procedure in an experimental model of TCA in comparison with an antimesenteric aganglionic colon patch in rats. TCA was produced by serosal application of 0.1% benzalkonium chloride in 18 Sprague-Dawley rats (250 g). Five additional rats served as operated controls. Ileoanal pull-through was performed in 18 TCA rats, in conjunction with the Martin extended Duhamel procedure using the entire colon in six rats, with an aganglionic colon patch in nine (using the right [3 rats], transverse [3 rats] and left [3 rats] colon), and without other procedures in three rats. Animals were evaluated for survival, weight change, food intake, stool consistency and volume, barium enema, complete blood cell count (CBC), total protein, and serum electrolytes at 4 and 12 weeks. Survival was 83% (5/6) rats with the Martin procedure, 100% in the nine rats with various colon patches, zero in three rats with ileoanal pull-through alone, and 100% in controls. Rats with the Martin procedure gained 2.2 +/- 3.27% of preoperative weight, while controls gained 11.2 +/- 0.52% at 4 weeks. All other rats showed an early weight loss. At 12 weeks, right and transverse colon patched rats had weight gain. Blood count and laboratory studies were similar in each group. Barium enema showed rapid transit in rats with ileoanal pull-through, and slower transit in rats with colon patches or the Martin procedure.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
42.
Biodegradable copolymers of L -lactic acid (L -LA) and DL -α-hydroxy acids with relatively low molecular weights, for example L -LA/DL -lactic acid (DL -LA), L -LA/DL -α-hydroxybutyric acid (DL -HBA), L -LA/DL -α-hydroxyisovaleric acid (DL -HIVA), and L -LA/DL -α-hydroxyisocaproic acid (DL -HICA), were synthesized by quantitative direct copolycondensation without catalysts at 200°C. The in vitro degradation, which was evaluated by measuring the weight loss of these copolymers in M/15 phosphate buffer solution (pH 7,2) without enzymes at 37°C, is strongly dependent on the kind and molecular weight of these copolymers, resulting in the formation of different degradation patterns such as parabola type (L -LA/DL -HBA system), linear type (L -LA/DL -LA system), and S type (L -LA/DL -HIVA and L -LA/DL -HICA systems).  相似文献   
43.
44.
We report on a 66-year-old woman in whom GPi pallidotomy produced progressive and eventually complete relief of hemichorea/ballism (HCB) after a subthalamic hemorrhage. Although choreoballistic movements were unchanged during and immediately after the surgery, the symptoms were gradually improved and consequently abolished by 5 days postoperatively. HCB has never recurred up to the present (9 months follow-up period). This note is the first report describing detailed postsurgical process in HCB relief after pallidotomy.  相似文献   
45.
46.
Epidural midazolam with saline--optimal dose for postoperative pain]   总被引:3,自引:0,他引:3  
Optimal dose of epidural midazolam with saline for postoperative pain relief was investigated. Forty three patients for upper abdominal surgery were divided into 5 groups. Each group had either 10 ml saline only (saline group), 10 ml saline + midazolam 0.025 mg.kg-1 (0.025 group), 10 ml saline + midazolam 0.05 mg.kg-1 (0.05 group), 10 ml saline + midazolam 0.075 mg.kg-1 (0.075 group), or 10 ml saline + midazolam 0.1 mg.kg-1 (0.1 group) administered epidurally for complaint of postoperative pain. Blood pressure (BP), heart rate (HR), respiratory rate (RR) and sedation score (SS) were monitored for 120 minutes, and the time interval for next analgesics (TNA) was checked. In each group, BP was unchanged compared with preinjection level. HR changes were less in 0.05 and 0.1 group than in others. RR changes were less in 0.025 and 0.05 group than in others. Optimal SSs were obtained in 0.025 and 0.05 groups. In 0.075 and 0.1 groups, many patients fell into complete sleep (not responded to verbal command). TNA was about 2 hours in 0.025 and 0.05 groups, over 6 hours in 0.075 and 0.1 groups. Complete sleep was the cause of long TNA in 0.075 and 0.1 groups. It was concluded that optimal dose of epidural midazolam with saline 10 ml was 0.05 mg.kg-1 for postoperative pain relief after upper abdominal surgery.  相似文献   
47.
Y Goto  W Taki  H Kikuchi 《Brain and nerve》1988,40(11):1045-1049
Using the four-vessel extracranial one staged occlusion model of adult Wistar rats, we analyzed quantitatively released free fatty acids during ischemia. Also have we analyzed the effect of bifemelane to reduce free fatty acid accumulation after the onset of ischemia. Bifemelane (15 mg/kg, 30 mg/kg) and saline as control were intraperitoneally administered to adult Wistar rat prior to 30 minutes of experimentally induced ischemia. The results obtained were analyzed by one or two way analysis of variance (ANOVA). Physiological variables (systemic arterial pressure, PaO2, PaCO2, pH) did not change significantly in all four experimental groups. Total free fatty acid levels (sum of 5 fatty acid) increased significantly after ischemia (30 minutes). Higher dose (30 mg/kg) of bifemelane administration significantly reduced total free fatty acid accumulation, though lower dose (15 mg/kg) did have no effect. Bifemelane (30 mg/kg) reduced significant accumulation in the amount of saturated and monounsaturated fatty acid (palmitic acid [16:0], stearic acid [18:0] and oleic acid [18:1]). Arachidonic (20:4) and docosahexaenoic (22:6) acid failed to show any effective reduction by bifemelane pre-treatment of lower nor higher dose. Bifemelane is supposed to have many pharmacological effects such as increase in cerebral blood flow, augmentation of glucose uptake, monoamine metabolism, cerebral vasodilatation and platelet antiaggregation. Free fatty acid accumulation is effectively suppressed by the higher dose of bifemelane administration. Although the exact mechanism are not clearly identified by the result obtained in this experiment, selective inhibition of accumulation in saturated and monounsaturated fatty acids by bifemelane pretreatment may be obtained by the improvement of energy metabolism, which may help to reacylation of fatty acid into phospholipid.  相似文献   
48.
Surgical Treatment of Intractable Seizures Due to Hypothalamic Hamartoma   总被引:16,自引:7,他引:9  
Summary: A 6.5-year-old boy developed seizures at age 2.8 years consisting of episodes of unconsciousness and laughing attacks. By age 6 years, multiple seizure types, including generalized tonic-clonic (GTC), complex partial (CPS) and akinetic seizures, and drop attacks were occurring several times daily. EEG showed multifocal epileptic discharges. Antiepileptic drugs (AEDs) did not control the seizures. With progression of the epilepsy, cognitive deterioration developed. There were no manifestations of precocious puberty. Neuroimaging disclosed a suprasellar mass in continuity with the hypothalamus, and a diagnosis of hypothalamic hamartoma was made. After surgical resection of the hamartoma, the seizures were completely alleviated, and the epileptic EEG discharges disappeared. Improvement of mental function was also noted.  相似文献   
49.
50.
Recent studies have shown that angiogenesis-stimulatory factors exist in ocular tissues and play a crucial role in the development of some eye disorders such as diabetic retinopathy. However, there are few reports that studied location of angiogenesis factors in ocular tissues of experimental animals. We studied angiogenesis factors in ocular tissues of normal rabbits by chorioallantoic membrane (CAM) assay. Extracts derived from the retina, iris-ciliary body and optic nerve showed an evident activity of angiogenesis. Retinal extracts at 10 micrograms showed a strong angiogenic activity in 50% of CAMs (p less than 0.01). On the other hand, bovine serum albumin which is heterogeneous protein showed only a slight angiogenic activity at a high concentration (1,000 micrograms). The iris-ciliary body and optic nerve showed also an angiogenic activity as did the retina. Extracts from the heart, liver and serum showed no activity of angiogenesis. Thus, angiogenic activity was strongly present in the ocular tissues, especially in retina of the normal rabbits.  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