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   17239篇
  免费   1476篇
  国内免费   40篇
耳鼻咽喉   164篇
儿科学   573篇
妇产科学   477篇
基础医学   2388篇
口腔科学   183篇
临床医学   2025篇
内科学   3411篇
皮肤病学   260篇
神经病学   2002篇
特种医学   339篇
外科学   1810篇
综合类   103篇
一般理论   18篇
预防医学   2430篇
眼科学   230篇
药学   1048篇
中国医学   10篇
肿瘤学   1284篇
  2024年   23篇
  2023年   310篇
  2022年   277篇
  2021年   1171篇
  2020年   699篇
  2019年   978篇
  2018年   1038篇
  2017年   697篇
  2016年   705篇
  2015年   763篇
  2014年   979篇
  2013年   1211篇
  2012年   1754篇
  2011年   1707篇
  2010年   787篇
  2009年   659篇
  2008年   1061篇
  2007年   906篇
  2006年   784篇
  2005年   614篇
  2004年   493篇
  2003年   414篇
  2002年   331篇
  2001年   36篇
  2000年   30篇
  1999年   38篇
  1998年   46篇
  1997年   28篇
  1996年   13篇
  1995年   16篇
  1994年   12篇
  1993年   8篇
  1992年   16篇
  1991年   8篇
  1990年   11篇
  1989年   9篇
  1988年   11篇
  1987年   4篇
  1985年   11篇
  1984年   11篇
  1982年   5篇
  1980年   6篇
  1979年   9篇
  1977年   4篇
  1976年   7篇
  1975年   9篇
  1974年   6篇
  1973年   4篇
  1971年   6篇
  1964年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
OBJECTIVE: The aim of this study was to report on a new technique for examining aqueous humor. PARTICIPANTS: Aqueous humor samples obtained from 198 patients (cataract: n=66 eyes; age-related macular degeneration [AMD]: n=66; diabetic macular edema: n=66) were in vitro examined by mid infrared spectroscopy. After training and validating the technique, 66 samples were taken for the final independent prediction. RESULTS: In computerized analysis of the spectrometric data, 22 (100%) cataract eyes were diagnosed as the cataract group, 17 (77%) diabetic macular edema eyes were diagnosed as the diabetic macular edema group, and 14 (64%) eyes with AMD were diagnosed as the AMD group. Mid infrared spectrometry could statistically significantly (P=0.004) differentiate between the 3 study groups. CONCLUSIONS: Mid infrared spectroscopic examination of aqueous humor may be able to differentiate eyes with cataract, AMD, or diabetic macular edema.  相似文献   
992.
993.
994.
This study reports on the validation of a scale to assess adolescent girls' frequency of sexual communication with their parents. The Parent-Adolescent Communication Scale (PACS) was administered to 522 African American female adolescents ranging in age from 14 to 18. The PACS demonstrated satisfactory internal consistency (across multiple administrations) and acceptable test-retest reliability over a 12-month follow-up period. Concurrently, scores on the PACS were correlated with frequency of sexual communication with partner, sexual communication self-efficacy (boyfriend), perceived parental knowledge, family support, depression, and condom use with steady male sex partners. Prospectively, baseline PACS scores were correlated with frequency of sexual communication with partner and condom use. The present investigation indicates that the PACS is a reliable and valid measure of frequency of sexual communication between female adolescents and their parents. Utility of the PACS for researchers and practitioners is discussed.  相似文献   
995.
Posttraumatic stress disorder (PTSD) is an anxiety disorder that occurs after a traumatic event and has been linked to psychiatric and physical health declines. Rates of PTSD are far higher in individuals with low incomes and who reside in urban areas compared to the general population. In this study, 250 urban health care-seeking women were interviewed for a diagnosis of PTSD, major depressive disorder, and also the experience of traumatic events. Multivariate logistic regressions were used to determine the associations between traumatic events and PTSD development. Survival analysis was used to determine if PTSD developed from assaultive and nonassaultive events differed in symptom duration. Eighty-six percent of women reported at least one traumatic event, 14.8% of women were diagnosed with current PTSD, and 19.6% with past PTSD. More than half of women with PTSD had comorbid depression. Assaultive traumatic events were most predictive of PTSD development. More than two thirds of the women who developed PTSD developed chronic PTSD. Women who developed PTSD from assaultive events experienced PTSD for at least twice the duration of women who developed PTSD from nonassaultive events. In conclusion, PTSD was very prevalent in urban health care-seeking women. Assaultive violence was most predictive of PTSD development and also nonremittance.  相似文献   
996.
We examined the antidepressant efficacy and dose-response pattern of the n-3 docosahexaenoic acid (DHA). Thirty-five depressed adult outpatients (46% women; mean age 42+/-14 years) with a 17-item Hamilton-Depression Scale (HAM-D-17) score of >/=18 were randomized into one of three double-blind dosing arms for 12 weeks. Group A (n=14): 1 g/day of oral DHA; Group B (n=11): 2 g/day; and Group C (n=10): 4 g/day. We measured HAM-D-17 scores, plasma DHA, eicosapentaenoic acid (EPA), and n-6/n-3 ratio. Completer response rates (>/=50% decrease in HAM-D-17 score) were 83% for Group A, 40% for Group B, and 0% for Group C; Groups A and B had significant decreases in HAM-D-17 scores (p<0.05). For completers and intent-to-treat subjects, plasma DHA increased significantly (p<0.05), EPA had little change (p>0.05), and n-6/n-3 decreased significantly (p<0.05). DHA may be effective for depression at lower doses.  相似文献   
997.
PURPOSE: The purpose of this study was to characterize the activity of the Bcl-2 protein family inhibitor ABT-263 in a panel of small cell lung cancer (SCLC) xenograft models. EXPERIMENTAL DESIGN: A panel of 11 SCLC xenograft models was established to evaluate the efficacy of ABT-263. Single agent activity was examined on a continuous dosing schedule in each of these models. The H146 model was used to further evaluate dose and schedule, comparison to standard cytotoxic agents, and induction of apoptosis. RESULTS: ABT-263 exhibited a range of antitumor activity, leading to complete tumor regression in several models. Significant regressions of tumors as large as 1 cc were also observed. The efficacy of ABT-263 was also quite durable; in several cases, minimal tumor regrowth was noted several weeks after the cessation of treatment. Antitumor effects were equal or superior to that of several clinically approved cytotoxic agents. Regression of large established tumors was observed through several cycles of therapy and efficacy was retained in a Pgp-1 overexpressing line. Significant efficacy was observed on several dose and therapeutic schedules and was associated with significant induction of apoptosis. CONCLUSIONS: ABT-263 is a potent, orally bioavailable inhibitor of Bcl-2 family proteins that has recently entered clinical trials. The efficacy data reported here suggest that SCLC is a promising area of clinical investigation with this agent.  相似文献   
998.

Background  

Rearrangement of the short arm of chromosome 8 (8p) is very common in epithelial cancers such as breast cancer. Usually there is an unbalanced translocation breakpoint in 8p12 (29.7 Mb – 38.5 Mb) with loss of distal 8p, sometimes with proximal amplification of 8p11-12. Rearrangements in 8p11-12 have been investigated using high-resolution array CGH, but the first 30 Mb of 8p are less well characterised, although this region contains several proposed tumour suppressor genes.  相似文献   
999.
Previous studies in the K14-HPV/E2 mouse model of cervical carcinogenesis demonstrated that infiltrating macrophages are the major source of matrix metalloproteinase 9 (MMP-9), a metalloprotease important for tumor angiogenesis and progression. We observed increased expression of the macrophage chemoattractant, CCL2, and its receptor, CCR2, concomitant with macrophage influx and MMP-9 expression. To study the role of CCL2-CCR2 signaling in cervical tumorigenesis, we generated CCR2-deficient K14-HPV/E2 mice. Cervixes of CCR2-null mice contained significantly fewer macrophages. Surprisingly, there was only a modest delay in time to progression from dysplasia to carcinoma in the CCR2-deficient mice, and no difference in end-stage tumor incidence or burden. Moreover, there was an unexpected persistence of MMP-9 activity, associated with increased abundance of MMP-9+ neutrophils in tumors from CCR2-null mice. In vitro bioassays revealed that macrophages produce soluble factor(s) that can suppress neutrophil dynamics, as evidenced by reduced chemotaxis in response to CXCL8, and impaired invasion into three-dimensional tumor masses grown in vitro. Our data suggest a mechanism whereby CCL2 attracts proangiogenic CCR2+ macrophages with the ancillary capability to limit infiltration by neutrophils. If such tumor-promoting macrophages are suppressed, MMP-9+ neutrophils are then recruited, providing alternative paracrine support for tumor angiogenesis and progression.  相似文献   
1000.
Women's Lives After an HIV-Positive Diagnosis: Disclosure and Violence   总被引:5,自引:0,他引:5  

Objectives: This research addresses four questions: (1) What role do health care providers play in women's disclosure to others of their HIV-positive status? (2) What are women's concerns and experiences with disclosure? (3) What violence do women living with HIV experience? (4) How is the violence related to their diagnosis and disclosures? Methods: Participants were 310 HIV-positive women enrolled in an HIV primary care clinic in an urban teaching hospital. Women were interviewed once using both quantitative and qualitative methods. Results: Women had known they were HIV-positive for an average of 5.8 years; 22% had an HIV-positive partner; 58% had disclosed their status to more than 10 people; and 68% had experienced physical abuse and 32% sexual abuse as an adult. Fifty-seven percent of the sample reported that a health care provider had told them to disclose to their sex partners. Women who were afraid of disclosure-related violence (29%) were significantly more likely than those who were not to report that a health care provider helped them with disclosure (21% vs. 10%). Although 4% reported physical abuse following a disclosure event, 45% reported experiencing emotional, physical, or sexual abuse at some time after their diagnosis. Risk factors for experiencing abuse after diagnosis were a prior history of abuse, drug use, less income, younger age, length of time since diagnosis, and having a partner whose HIV status was negative or unknown. Conclusions: Identifying women at risk for abuse after an HIV-positive diagnosis is important for those who provide HIV testing and care. Routine screening for interpersonal violence should be incorporated into HIV posttest counseling and continuing primary care services.

  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