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   11696篇
  免费   882篇
  国内免费   31篇
耳鼻咽喉   84篇
儿科学   405篇
妇产科学   441篇
基础医学   1377篇
口腔科学   305篇
临床医学   1260篇
内科学   2838篇
皮肤病学   296篇
神经病学   836篇
特种医学   489篇
外国民族医学   3篇
外科学   1636篇
综合类   177篇
一般理论   7篇
预防医学   921篇
眼科学   400篇
药学   606篇
  1篇
中国医学   6篇
肿瘤学   521篇
  2021年   127篇
  2019年   126篇
  2018年   177篇
  2017年   148篇
  2016年   124篇
  2015年   153篇
  2014年   215篇
  2013年   334篇
  2012年   456篇
  2011年   484篇
  2010年   304篇
  2009年   267篇
  2008年   450篇
  2007年   434篇
  2006年   469篇
  2005年   480篇
  2004年   444篇
  2003年   413篇
  2002年   417篇
  2001年   426篇
  2000年   381篇
  1999年   325篇
  1998年   120篇
  1997年   109篇
  1996年   119篇
  1995年   101篇
  1994年   109篇
  1993年   111篇
  1992年   339篇
  1991年   323篇
  1990年   289篇
  1989年   310篇
  1988年   274篇
  1987年   294篇
  1986年   248篇
  1985年   223篇
  1984年   175篇
  1983年   167篇
  1982年   104篇
  1981年   107篇
  1980年   110篇
  1979年   175篇
  1978年   136篇
  1977年   123篇
  1976年   101篇
  1975年   95篇
  1974年   116篇
  1973年   115篇
  1972年   97篇
  1970年   95篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
21.
Pemedolac Na, 1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano [3,4-b] indole-1-acetic acid sodium salt, exhibited equipotent analgesic effects after oral, iv, and im administration, suggesting that it is well absorbed. In mouse writhing models, the ED50 values ranged from 0.3 mg (0.81 μmol)/kg (vs. acetylcholine) to 4.3 mg (11.6 μmol)/kg (vs. paraphenylbenzoquinone [PBQ]). In the rat Randall-Selitto model, the ED50 o the compound was approximately 0.001 mg (2.7 nmol)/kg, with a flat dose response curve. The peak effects lasted for 7–9 h, 10–18 h, and 5 h following oral, im, and iv injections, respectively. Intracerebroventricular (i.c.v.) injections of pemedolac Na inhibited the PBQ-induced writing in mice with an ED50 of 43.5 μg (0.12 μmol)/mouse, and this effect was not antagonized by naloxone. It was inactive in the hot plate and tail flick tests, demonstrating that pemedolac Na does not act via an opiate mechanism. These results indicate that pemedolac Na is a viable parenteral and oral analgesic, typified by high analgesic potency, a rapid onset and long duration of action, and an extremely wide safety index. © Wiley-Liss, Inc.  相似文献   
22.
23.
Dermatologic changes associated with interleukin 2 administration   总被引:6,自引:0,他引:6  
A A Gaspari  M T Lotze  S A Rosenberg  J B Stern  S I Katz 《JAMA》1987,258(12):1624-1629
We have prospectively evaluated the skin changes that occurred in ten patients who were undergoing immunotherapy with interleukin 2 (IL-2) and autologous lymphokine-activated killer cells to treat cancer. Serial skin biopsy specimens were obtained before therapy (baseline), during IL-2 administration, and during IL-2/lymphokine-activated killer cell infusion. All patients developed an eruption that was characterized by macular erythema, with burning and pruritus of the skin. It began after two or three days of IL-2 infusion and was usually localized to the head and neck; it occasionally became generalized (ie, erythroderma). The eruption resolved with desquamation within 48 to 72 hours after cessation of infusion of IL-2. Histologically, the changes were not specific. The only consistent immunohistological finding noted was the presence of DR+/Leu-4+ lymphoid cells surrounding blood vessels in the papillary dermis, with fewer of these cells in the epidermis. There was no difference between the clinical or histological features of the eruption that occurred with IL-2 alone and that which occurred with IL-2 and lymphokine-activated killer cell infusion, suggesting that the cutaneous effects were mediated by IL-2 alone.  相似文献   
24.
Impaired recall for early items (primacy) and late items (recency) on word list recall tests are seen in Alzheimer's disease (AD). We compared conventional scoring on the Telephone Instrument for Cognitive Status (TICS) recall list with scorings based on retention-weighted recall (RWR: each item weighted by its serial position) in older adults participating in a community-based aging study. Subjects with mild AD (N=18) did not differ from those without dementia (N=231) with respect to recency (46% vs. 59%, p = 0.2), but had impaired primacy (2% vs. 39%, p < .001) on word recall on the TICS. RWR scoring improved the effect size (1.52 SD) compared to conventional scoring (1.08 SD). With a fixed sensitivity of 85%, specificity was lower using conventional scoring (56%) than RWR (76%) scoring. Our findings suggest that optimized RWR scoring of word list free recall can improve detection of mild AD compared to conventional scoring.  相似文献   
25.
26.
27.
Glucose is provided to cells by a family of glucose transport facilitators known as GLUTs. These transporters are expressed in a tissue specific manner and are overexpressed in many primary tumors of these tissues. Regulation of glucose transport facilitator expression has been demonstrated in endometrial tissue and endometrial adenocarcinoma. The following experiments were conducted to quantify and localize the expression of GLUT1 and GLUT8 in benign endometrium and compare this expression to endometrial cancer. Endometrial tissue samples were obtained from random hysterectomy specimens of patients with benign indications for surgery and endometrial cancer. Immunoblot and immunolocatization studies were performed using GLUT1 and GLUT8 specific antisera. Endometrial samples from 65 women who had undergone hysterectomy were examined (n=38 benign, n=27 malignant). A 44 and a 35.4 kDa immunoreacive species was demonstrated in endometrium and endometrial cancer for GLUT1 and GLUT8, respectively. Upregulation of GLUT1 expression was demonstrated with increasing grade of tumors (P<0.002). GLUT8 expression was increased in all tumor subtypes compared to atrophic endometrium (P<0.001). Apical localization by GLUT1 and GLUT8 was demonstrated in endometrial glands. GLUT1 and GLUT8 demonstrated diffuse intracellular localization in the cancer subtypes. GLUT1 and GLUT8 are expressed in both human endometrium and endometrial cancer. There appears to be a step-wise progression in GLUT1 and GLUT8 expression as tumor histopathology worsens. GLUT1 and GLUT8 may be important markers in tumor differentiation, as well as providing energy to rapidly dividing tumor cells.  相似文献   
28.
Epidemiologic evidence suggests that a full-term pregnancy may affect maternal risk of breast cancer later in life. The objective of this cross-sectional study was to compare circulating levels of maternal hormones affecting breast differentiation (human chorionic gonadotropin and prolactin) and proliferation [alpha-fetoprotein, insulin-like growth factor I (IGF-I), and estradiol] between women at a low to moderate risk (Asians and Hispanics), as compared with women at a high risk for breast cancer (Caucasians and African-Americans). Between May 2002 and December 2004, a total of 586 pregnant women were approached during a routine prenatal visit. Among them, 450 women (206 Caucasian, 126 Asian, 88 Hispanic, and 30 African-American) met the inclusion criteria and signed the informed consent. Only singleton pregnancies were considered. Blood samples were drawn during the second trimester of pregnancy. Laboratory analyses were done using the IMMULITE 2000 immunoassay system. Gestational age standardized mean levels of estradiol, IGF-I, and prolactin were significantly higher in Hispanic women compared with Caucasian women. Mean concentration of IGF-I was significantly higher in African-American women compared with Caucasian and Asian women. No significant differences in pregnancy hormone levels were observed between Caucasian and Asian (predominantly second-generation Chinese) women in this study. Irrespective of ethnicity, women who had their first pregnancy had substantially higher mean levels of alpha-fetoprotein, human chorionic gonadotropin, estradiol, and prolactin compared with women who previously had at least one full-term pregnancy. These data suggest that circulating pregnancy hormone levels may explain some of the ethnic differences in breast cancer risk.  相似文献   
29.
OBJECTIVE: Authors evaluated the association between use/dosage of risperidone (RIS) and falls in a residential-care dementia population. METHODS: Authors performed secondary analysis of data from ambulatory patients in a randomized, double-blind, placebo-controlled, 12-week trial of three RIS dosages (0.5 mg/day, 1 mg/day, 2 mg/day). Outcomes included number of fallers, rate of falls, and time until the first fall after randomization. Additional analyses evaluated wandering as a potential moderating or mediating variable. RESULTS: The ambulatory sample included 537 subjects. Of those, 22.3% on placebo, 18.0% on RIS 0.5 mg/day, 12.7% on 1 mg/day, and 27.3% on 2 mg/day, respectively, fell during the trial. The difference between the RIS 1 mg/day group and placebo was significant, with a significantly lower hazard ratio in the RIS 1-mg/day group than placebo. Wandering was associated with an increased risk of falls. Among 205 patients with the highest levels of wandering at baseline, RIS 1 mg/day was associated with approximately a 70% reduction in risk for falls versus placebo condition. However, in those with the lowest levels of wandering at baseline, RIS 2 mg/day may have increased the risk of falls. CONCLUSIONS: Evaluating the benefits versus risks of risperidone in patients with dementia is complex and must consider multiple outcomes as a function of dose. At 1 mg/day, RIS was associated with decreased falls, especially in patients who exhibit wandering. However, at 2 mg/day, it may increase the risk of falls in ambulatory individuals with low levels of wandering.  相似文献   
30.
This study provides additional information on the psychometric properties of the Sexual Aversion Scale (SAS). Results suggest a positive relationship between sexual aversion, generalized anxiety, and history of sexual victimization. Variables such as age and religiosity were unrelated to scores on the SAS, although females reported significantly more sexual anxiety than males. The factor structure of the SAS is described and suggests that sexual aversion is a multifaceted problem with at least three and possibly four different dimensions.  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