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   5944篇
  免费   338篇
  国内免费   60篇
耳鼻咽喉   70篇
儿科学   389篇
妇产科学   81篇
基础医学   788篇
口腔科学   150篇
临床医学   460篇
内科学   1142篇
皮肤病学   128篇
神经病学   314篇
特种医学   206篇
外科学   844篇
综合类   239篇
一般理论   3篇
预防医学   348篇
眼科学   130篇
药学   596篇
  1篇
中国医学   41篇
肿瘤学   412篇
  2023年   30篇
  2022年   70篇
  2021年   187篇
  2020年   99篇
  2019年   133篇
  2018年   161篇
  2017年   117篇
  2016年   134篇
  2015年   169篇
  2014年   218篇
  2013年   282篇
  2012年   353篇
  2011年   342篇
  2010年   237篇
  2009年   197篇
  2008年   290篇
  2007年   264篇
  2006年   301篇
  2005年   245篇
  2004年   211篇
  2003年   194篇
  2002年   187篇
  2001年   141篇
  2000年   152篇
  1999年   127篇
  1998年   88篇
  1997年   71篇
  1996年   66篇
  1995年   46篇
  1994年   37篇
  1993年   40篇
  1992年   97篇
  1991年   82篇
  1990年   72篇
  1989年   94篇
  1988年   77篇
  1987年   71篇
  1986年   70篇
  1985年   66篇
  1984年   51篇
  1983年   28篇
  1982年   28篇
  1980年   30篇
  1979年   42篇
  1977年   36篇
  1975年   38篇
  1974年   29篇
  1973年   25篇
  1972年   32篇
  1971年   25篇
排序方式: 共有6342条查询结果,搜索用时 62 毫秒
81.
Serum Adenosine Deaminase (ADA) enzyme levels were estimated in 61 patients with symptoms and signs suggestive of Pulmonary Tuberculosis and correlated with "Gold standards" such as smear positivity of sputum for Acid Fast bacilli, Tuberculin skin testing and Radiological evidence. The mean ADA levels in smear and Tuberculin negative patients was 13.13 +/- 5.97 u/L, while in those with smear and/or strongly positive Tuberculin reaction, the mean levels of ADA were 33.52 +/- 15.22 u/L. The mean serum ADA levels in 25 healthy voluntary donors with no evidence of active or old Tuberculous lesion, were found to be 16.5 +/- 3.18 u/L. The specificity, sensitivity, positive predictive value and negative predictive value of the test was found to be 87%, 71%, 90% and 66.5% respectively. The results conclude that the serum ADA value is sufficiently useful in identifying those patients in whom the diagnosis of Pulmonary Tuberculosis should be actively considered.  相似文献   
82.
In view of the dual burden of HIV infection and cervical cancers in India, this study was undertaken to estimate the prevalence of Pap smear abnormalities and human papillomavirus infection among HIV-infected women. Consecutive HIV-infected women attending voluntary counseling testing clinics were enrolled. Written informed consent, demographic information, Pap smears, cervical swabs for HPV typing and a blood sample for CD4+ cell count were collected. Treatment for opportunistic and sexually transmitted infections and reproductive tract infections was provided. Women with Pap smear abnormality were referred for further intervention. Between January 2003 and May 2004, 287 HIV-infected women were enrolled. Pap smear abnormalities were seen in 6.3% women and were more common among women aged 30 and above (P=0.042) and those who had suffered from opportunistic infections (P=0.004). In multivariate analysis, Pap smear abnormalities were associated independently with opportunistic infections (P=0.02, AOR 3.8, 95% CI 1.2--11.5). Of the 100 random cervical specimens screened for HPV 16 and 18 genotypes, 33% (95 CI 23.9--43.1) were positive for HPV 16/18. Of the 122 patients who returned for a follow-up visit, 5 patients (4.1%) who did not have Pap smear abnormality at baseline, had developed Pap smear abnormality. The incidence of Pap smear abnormalities was 5.5 per 100 person year of follow-up. In order to prevent thousands of deaths due to cervical cancer in India, there is a need for strengthening the Pap smear screening program and HPV vaccine development.  相似文献   
83.
The Journal of Behavioral Health Services & Research - Statistical reliability of the Treatment Perceptions Survey (TPS) questionnaire was examined using data from 19 California counties. The...  相似文献   
84.
There is a deficit of literature regarding the association between nickel allergy–induced symptoms and implanted devices. This report describes a case of nickel allergy causing debilitating migraine-like symptoms, failing to resolve with medical therapy, requiring surgical removal of the device and repair of the defect.  相似文献   
85.
86.
87.
Bulletin of Environmental Contamination and Toxicology - Halogenated compounds are one of the largest groups of environmental-hazardous chemicals. The removal of the halogen atom from the substrate...  相似文献   
88.
Tuberculosis of the middle ear it a rare disease. Due to change in the typical clinical pattern and decrease in incidence, there is a delayed or missed diagnosis and can lead to increased morbidity. We pretent 5 cases of Tuberculous Otitis Media treated over a period of 2 years, highlighting the fact that it must be considered as a differential diagnosis of persistent suppurative otitis media.  相似文献   
89.
Conventional cancer therapies such as surgery, chemotherapy and/or radiotherapy, are not always successful in providing long-term survival for cancer patients. One of the major problems with conventional cancer therapies is their inability to eradicate residual/metastatic tumor cells that are resistant to therapy. Therefore, it is necessary to develop new methods for treating such cancer cells in order to improve the clinical outcome of these patients. Despite antitumor effector mechanisms working against cancer cells in the host's body, tumor-cell-induced immunosuppression and or antigenic modulation by the tumor cells often help tumor cells escape host defense mechanisms. Therefore, one approach for treating residual cancer would be to enhance the host's own immunological/antitumor defense mechanisms. Immune cells that have a significant role in mediating antitumor responses include: T lymphocytes; natural killer (NK) cells; macrophages; and B lymphocytes. The ability of these immune cells to effectively destroy malignant cells is carefully governed by chemical mediators in the form of proteins otherwise known as cytokines. Many cytokines (interleukins, interferons, and tumor necrosis factor) have been shown to enhance in vitro and in vivo effector cell antitumor cytotoxic activities. Utilization of cytokines in conjunction with effector cells can also mediate significant antitumor responses in both animal models and cancer patients. One of the major problems associated with systemic treatment with cytokines is the development of dose limiting toxicities. Currently, attempts to reduce this problem include developing techniques to allow for the preferential release of cytokines in proximity to the tumor cell. In this regard, effector cells or tumor cells that have been genetically engineered to secrete cytokine(s) may be useful in localizing an immune response, preferably at the tumor site. Clinical trial using cytokine gene transfected cells for treating cancer are currently under investigation. With the availability of recombinant lymphokines and with our ability to genetically modify effector cells and tumor cells this hopefully will allow us to improve current therapeutic modalities for treating cancer.  相似文献   
90.
OBJECTIVES: This study examined client and program characteristics that predict posttreatment cocaine abstinence among cocaine abusers with different treatment histories. METHODS: Cocaine abusers (n = 507) treated in 18 residential programs were interviewed at intake and 1-year follow-up as part of the nationwide Drug Abuse Treatment Outcome Study (DATOS). Program directors provided the program-level data in a mail survey. We applied the hierarchical linear modeling approach for the analysis. RESULTS: No prior treatment and longer retention in DATOS programs were positive predictors of posttreatment abstinence. The interactive effect of these 2 variables was also significantly positive. Program that offered legal services and included recovering staff increased their clients' likelihood of cocaine abstinence. Crack use at both the client and program level predicted negative impact. None of the program variables assessed differentially affected the outcomes of first-timers and repeaters. CONCLUSIONS: Although treatment repeaters were relatively difficult to treat, their likelihood of achieving abstinence was similar to that of first-timers if they were retained in treatment for a sufficient time. First-timers and repeaters responded similarly to the treatment program characteristics examined. The treatment and policy implications of these findings are discussed.  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