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   5017篇
  免费   526篇
  国内免费   9篇
耳鼻咽喉   142篇
儿科学   127篇
妇产科学   94篇
基础医学   861篇
口腔科学   155篇
临床医学   560篇
内科学   843篇
皮肤病学   67篇
神经病学   578篇
特种医学   182篇
外国民族医学   1篇
外科学   805篇
综合类   40篇
一般理论   2篇
预防医学   357篇
眼科学   99篇
药学   306篇
中国医学   5篇
肿瘤学   328篇
  2023年   68篇
  2022年   109篇
  2021年   257篇
  2020年   149篇
  2019年   217篇
  2018年   256篇
  2017年   183篇
  2016年   174篇
  2015年   205篇
  2014年   247篇
  2013年   281篇
  2012年   380篇
  2011年   387篇
  2010年   214篇
  2009年   166篇
  2008年   252篇
  2007年   242篇
  2006年   199篇
  2005年   145篇
  2004年   156篇
  2003年   124篇
  2002年   111篇
  2001年   45篇
  2000年   62篇
  1999年   46篇
  1998年   24篇
  1997年   30篇
  1996年   24篇
  1995年   28篇
  1994年   17篇
  1993年   16篇
  1992年   54篇
  1991年   57篇
  1990年   50篇
  1989年   38篇
  1988年   44篇
  1987年   39篇
  1986年   49篇
  1985年   58篇
  1984年   36篇
  1983年   35篇
  1982年   26篇
  1981年   26篇
  1979年   31篇
  1978年   28篇
  1977年   22篇
  1975年   14篇
  1973年   12篇
  1972年   20篇
  1970年   14篇
排序方式: 共有5552条查询结果,搜索用时 15 毫秒
61.
62.
Alcohol problems are common among patients seen in primary care settings, yet they are often missed by physicians. This article offers a model for alcohol screening designed to facilitate early identification of alcohol problems. This approach emphasizes the heterogeneity of alcohol problems and looks at alcohol use along a spectrum, with different risks depending on where in the spectrum a patient falls. The authors provide practical suggestions on integrating alcohol screening and early intervention into routine care.  相似文献   
63.
64.
In response to tremendous growth of managed care and threats to financial stability and job security, the Greater Baltimore Medical Center (GBMC) restructured itself into independent business units. The radiology department at GBMC resolved to reduce cost per unit-of-service, improve service, determine optimal staffing levels and reduce the number of layers of organization. It was decided to achieve those goals by implementing self-directed work groups. Staff buy-in was critical to success of the project. To begin, the staff was educated intensively about current trends in healthcare, managed care and potential changes in the job market. The radiology department was allowed to reduce the size of its staff through attrition and worked hard to focus staff concern on the impact each individual could have on the bottom line and the resultant effect on job security. Self-directed work groups were designed on a matrix that used small "service teams" in combinations to form larger "work groups." Actual work and daily activities occur at the service team level; information exchange and major decisions occue at the work group level. Seventeen months after beginning the project and 10 months after implementation, the organization has flattened, staff members have adjusted well to new roles, there have been no lay-offs, and the matrix system of small and large groups have proved particularly valuable.  相似文献   
65.
Medical ethics     
Brandon S 《Lancet》1982,1(8268):388
  相似文献   
66.
Psychological adjustment was assessed in a sample of 525 female and 191 male adoptees. Analyses were conducted by gender; by search status, i.e., those who had never searched, those who were searching, and those who had made contact with their biological parents; and by history of mental health service utilization. Compared to normative data, the sample reported significantly higher levels of psychological maladjustment; only women adoptees scored higher on a scale measuring anger. Overall, adoptees' scores were elevated but did not approach levels typical of outpatient populations.  相似文献   
67.
Purpose: 10-Hydroxycamptothecin (HCPT) is an indole alkaloid isolated from a Chinese tree, Camptotheca acuminata, and has a wide spectrum of anticancer activity in vitro and in vivo mainly through inhibitory effects on topoisomerase I. HCPT has been shown to be more potent and less toxic than camptothecin and has recently undergone clinical trials. To determine how HCPT might be best used as an anticancer agent, preclinical studies of the pharmacokinetics, tissue distribution, metabolism and elimination of HCPT in rats were undertaken. Methods: HCPT was administered to rats by i.v. bolus injection at doses of 1, 3, and 10 mg/kg body weight. HCPT (lactone and carboxylate) and its metabolites in plasma, urine, feces, and various tissues were quantitated by reversed-phase HPLC. Pharmacokinetic parameters were then estimated. Results: Following i.v. administration at doses of 3 or 10 mg/kg, the plasma concentration-time profile for lactone HCPT could be best described by a three-compartment model, with terminal elimination half-lives of 140.4 and 428.6 min, respectively. A two-compartment model was used to fit the plasma concentration-time curve at 1 mg/kg, with a terminal elimination half-life of 30.5 min. Carboxylate HCPT had a longer half-life than the lactone form of HCPT. During the initial 6 h after dosing, urinary excretion was the major route of elimination, and fecal excretion became the major route of elimination thereafter. HCPT was widely distributed to various tissues including the enterohepatic system, kidney, and bone marrow. The lactone form of HCPT was detectable in various tissues examined up to 72 h after dosing at all the three test doses. HCPT glucuronides were present in plasma, urine, feces and various tissues. No significant toxicity was observed at doses of 1 or 3 mg/kg. Polyuria and hematuria were observed only during the initial 3 h after dosing at 10 mg/kg. Conclusions: Prolonged elimination of HCPT in vivo may have a significant impact on its therapeutic effects. HCPT is metabolized to its carboxylate form and glucuronides. Dose-dependent toxicity was observed with i.v. administration of HCPT. The results of this study should be useful in the design of future human trials with this anticancer drug. Received: 6 September 1996 / Accepted: 15 July 1997  相似文献   
68.
Purpose: The impact of severity of endometriosis on the outcome of in vitro fertilization (IVF) was analyzed in an uncontrolled, retrospective study in an academic IVF program. Methods: Sixty-one patients with a primary diagnosis of endometriosis undergoing 85 cycles of IVF were included in the study. Patients were divided according to the severity of disease based on the revised American Fertility Society (AFS) classification into groups A (stages I/II, or minimal/mild) and B (stages III/IV, or moderate/severe). Group A included 32 patients undergoing 45 IVF-embryo transfer (ET) cycles; group B included 29 patients undergoing 40 IVF cycles. Exclusion criteria were age older than 40 years, basal day 3 follicle stimulating hormone (FSH) greater than 20 IU/L, male-factor infertility, assisted hatching, and gamete intrafallopian transfer cases. Stimulation for IVF cycles was standard using pituitary down-regulation with gonadotropin-releasing hormone agonist in a midluteal protocol. Controlled ovarian hyperstimulation (COH) was achieved using a combination of FSH and human menopausal gonadotropin. Outcomes assessed included response to COH and number, maturity, and quality of oocytes retrieved. Fertilization, implantation, and pregnancy rates after IVF-ET were also analyzed. Results: The response to COH and the number, maturity, and quality of the oocytes was comparable between patients with varying severity of endometriosis. Fertilization rates for oocytes of patients in group B (stages III/IV) were significantly impaired compared to those in group A (stages I/II) (P = 0,004). The rates for implantation, clinical pregnancy, and miscarriage were comparable between the two groups. Conclusions: The reduced fertilization potential of the oocytes obtained from patients with severe endometriosis in the absence of male-factor infertility suggests an adverse biological impact of the advanced disease on the oocytes. The outcome of IVF-ET, however, is unaffected by increasing severity of endometriosis. This suggests that IVF may compensate for or overcome this reduction in the biological potential of the oocytes associated with severe disease, thus accounting for a comparable outcome irrespective of the severity of endometriosis.  相似文献   
69.
70.
Pharmaceutical Research - The lymphatic system plays crucial roles in tissue fluid balance, trafficking of immune cells, and the uptake of dietary lipid from the intestine. Given these roles there...  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