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   19953篇
  免费   1274篇
  国内免费   36篇
耳鼻咽喉   120篇
儿科学   687篇
妇产科学   707篇
基础医学   2705篇
口腔科学   273篇
临床医学   3323篇
内科学   3722篇
皮肤病学   203篇
神经病学   1982篇
特种医学   290篇
外科学   1432篇
综合类   248篇
一般理论   31篇
预防医学   2788篇
眼科学   154篇
药学   1244篇
中国医学   13篇
肿瘤学   1341篇
  2023年   87篇
  2022年   141篇
  2021年   331篇
  2020年   212篇
  2019年   374篇
  2018年   387篇
  2017年   279篇
  2016年   356篇
  2015年   404篇
  2014年   602篇
  2013年   963篇
  2012年   1385篇
  2011年   1385篇
  2010年   769篇
  2009年   755篇
  2008年   1355篇
  2007年   1332篇
  2006年   1337篇
  2005年   1370篇
  2004年   1308篇
  2003年   1284篇
  2002年   1241篇
  2001年   150篇
  2000年   138篇
  1999年   172篇
  1998年   253篇
  1997年   219篇
  1996年   183篇
  1995年   196篇
  1994年   173篇
  1993年   165篇
  1992年   142篇
  1991年   127篇
  1990年   114篇
  1989年   112篇
  1988年   112篇
  1987年   111篇
  1986年   80篇
  1985年   83篇
  1984年   120篇
  1983年   92篇
  1982年   126篇
  1981年   105篇
  1980年   109篇
  1979年   62篇
  1978年   66篇
  1977年   45篇
  1976年   51篇
  1975年   36篇
  1974年   46篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
941.
Psyllium seed husk (PSH) increases stool output and lowers blood cholesterol levels in humans. PSH and three fractions isolated from it were meal-fed to colectomized rats and fermented in vitro to test the hypothesis that viscous, gel-forming fraction B was responsible for these physiological actions. Control rats were fed 50 g/kg cellulose. The concentration of each PSH fraction in the test meals was equivalent to its concentration in PSH. Yields of the fractions were: A, 171; B, 575; and C, 129 g/kg of PSH. The wet weight and moisture content of ileal excreta (IE) from rats fed test meals containing PSH or fraction B were greater than those measured in excreta from rats fed meals containing cellulose or the other two PSH fractions. Total bile acids in IE did not differ between rats fed PSH or fraction B and were greater in these groups than in the other groups. Fraction A was not fermented during 3 d of incubation; fraction B was poorly fermented, with approximately 30% of the constituent sugars disappearing; and fraction C was rapidly and nearly completely fermented. These results indicate that the gel-forming fraction we isolated from PSH is the physiologically active component of the husks.  相似文献   
942.
The objective of this cross-sectional study was to evaluate mercury exposure and health status among Munduruku Indians from the community of Sai Cinza, State of Pará, Brazil. The population studied included 330 indians, who submitted to a questionnaire, clinical exams, and collection of hair, blood, urine, and feces. Mercury was measured in hair and fish. Although no person was found to have overt mercury intoxication, the mean levels of mercury in hair were elevated (14.45 micrograms/g for children from 7 to 12 years old, 15.70 micrograms/g for women between 14 and 44 years old, and 14.1 micrograms/g for the remaining population). Mercury levels in fish were below levels recommended by the World Health Organization, but rates of fish consumption were high. These results place this indigenous populations as a group under risk of mercury toxicity from the gold production.  相似文献   
943.
Most people are able to effectively process and respond to the sensory stimuli of daily life. But people who have sensory processing disorders struggle to form meaningful responses to sensory stimuli. As a result these individuals often exhibit problems with coordination, sensory-seeking or sensory-avoiding behaviors, and sensory modulation. The concept of sensory processing disorders stems from the work of occupational therapist Jean Ayres, Ph.D. Her work has launched a sensory-based treatment approach, primarily practiced by occupational therapists. This article outlines the theories supporting the notion of sensory processing disorders, options for assessment and treatment, and research on the efficacy of treatment.  相似文献   
944.
Colon cancer screening in the ambulatory setting   总被引:7,自引:0,他引:7  
BACKGROUND: Despite evidence of decreased mortality, recommendations for colon cancer screening have not been widely implemented by physicians. The objective of this study was to determine patient and clinician factors associated with screening for colon cancer. METHODS: A retrospective review of computerized medical records from primary care practices in an academic medical center was performed. Patients comprised men and women aged 50-74 with at least one visit between July 1, 1995 and June 30, 1997. Measurements included Fecal occult blood testing in the past 1 or 2 years, sigmoidoscopy in the previous 5 or 10 years, or colonoscopy in the past 10 years. RESULTS: A total of 6,039 patients were included in the analysis. Fecal occult blood testing had been performed in 44% of patients and sigmoidoscopy in 26%. Fifty-three percent of patients had undergone some type of colon cancer screening. In multivariate analysis, patient factors predictive of fecal occult blood testing included age (odds ratio (OR) per 5 years 1.05; 95% confidence interval 1.04, 1.06), Asian ethnicity (OR 1.23; 1.08, 1.41), number of visits during the study period (OR 1.05; 1.04, 1.06), recency of the last visit (OR 1.03; 1.02, 1.04), and having private insurance (OR 1.65; 1.04, 2.62). Predictors of sigmoidoscopy were similar except that patients with a family history of colon cancer and those with managed care insurance were also more likely to undergo sigmoidoscopy. Patients of nurse practitioners were less likely to receive fecal occult blood testing than were patients of physicians (OR 0.78; 0.65, 0.93). Patients of residents were less likely to undergo sigmoidoscopy than were patients of faculty (OR 0.79; 0.66, 0.94). CONCLUSIONS: Among patients seen in primary care practices, rates of colon cancer screening remain low, especially in patients who are younger, who have been seen less frequently, who are uninsured, or who do not have managed care insurance. Future research should explore these differences and should focus on increasing screening in all patient groups, especially in those who are underscreened.  相似文献   
945.
In this article, driving forces mapping, a technique derived from business strategy, is applied to five different client situations: an AIDS support organization, a men's bereavement group, an individual managing grief after abortion following diagnosis of a fetal anomaly, an individual dealing with an HIV diagnosis, and a couple who wanted to increase marital satisfaction. The technique was found to be helpful in goal definition, contracting and developing mutuality, and it was less helpful in introspective work. The article describes the work in ways that allow the reader to understand the process and apply the technique.  相似文献   
946.
Growing up is a precarious journey. Especially during the teenage years, kids hit occasional rocky patches as they struggle to come to grips with their changing bodies and the deepening demands of emotional relationships. Many young people cannot make nourishing connections with anyone because they have built a protective wall around themselves. Chipping down that wall is a long, painstaking process.

Nineteen-year-old Mia reminded me once again that when a person makes progress with one problem, often others emerge. After all, self-abusive behaviors develop for a reason: They help people cope with unbearable feelings.  相似文献   
947.
Akathisia is a relatively rare side effect with the newer atypical antipsychotic agents, particularly clozapine, and is easily misdiagnosed in children. As children are often unable to describe their symptoms verbally, their akathisia can be misdiagnosed as worsening of their psychosis, prompting an unnecessary increase in their neuroleptic dose. Two cases of childhood-onset schizophrenia associated with clozapine-induced akathisia responsive to beta-blocker treatment are described. Akathisia should be considered in all cases of apparent nonresponse to atypical antipsychotics.  相似文献   
948.
OBJECTIVE: The objective of this study was to identify benefit limits, diagnostic exclusions, and service exclusions of private behavioral health care plans that can influence the delivery of care to children. METHODS: A total of 128 commercial, employment-based behavioral health plans were examined for types of benefit limits, service exclusions, and diagnostic exclusions applicable to children. RESULTS: Almost half of the plans had restrictions on the number of outpatient visits, with limits ranging from 12 to 60 clinic visits a year. More than half of the plans had limitations on the number of inpatient days, ranging from 20 to 60 days a year. Diagnoses excluded from coverage included autism, mental retardation, problems related to child abuse, and impulse control disorders, such as kleptomania and pyromania. Half of the services excluded could be categorized as either social and human services or complementary medicine rather than as mental health care. CONCLUSIONS: Plans commonly had service and diagnostic exclusions that could disrupt children's health care. The results of the study emphasize a need to address the types of treatment covered by mental health insurance.  相似文献   
949.
To investigate familial effects of neuropsychological deficits associated with seizure disorders, we studied 65 families, in which 1 member had epilepsy. The disorders included childhood absence epilepsy (CAE), juvenile myoclonic epilepsy (JME) and temporal lobe epilepsy (TLE). Age-appropriate tests were administered to assess sustained attention, encoding and verbal memory, executive and focused attention and attentional flexibility/impulsivity. CAE probands attained lower scores than other probands in visual sustained attention and the ability to focus on and execute a visual-motor task. Scores of the unaffected relatives tended to fall between those of the probands and the controls. JME relatives had lower scores than other relatives in tests of visual and auditory sustained attention and attentional flexibility, and showed greater variability in response time. Behavioral information of this type may aid in the specification and differentiation of genetic linkages in affected families.  相似文献   
950.
Bipolar affective disorder (BPAD) is a complex neuropsychiatric disease characterized by extreme mood swings. Genetic influences affect the disease susceptibility substantially, yet the underlying mechanisms are unknown. We previously described a pedigree in which all five individuals with BPAD and one individual with recurrent major depression were carriers of a reciprocal chromosomal translocation t(9;11)(p24;q23). Gene content analyses of the breakpoint junctions revealed disruption of a gene (DIBD1) at 11q23, a genomic region that has also been implicated in schizophrenia and Tourette syndrome. DIBD1 is predicted to encode a mannosyltransferase similar to Saccaromyces cerevisiae Alg9p of the protein N-glycosylation pathway. The inborn errors of protein N-glycosylation cause congenital disorders of glycosylation in humans. DIBD1 shows uniform expression in the tested subregions of the brain by Northern analysis. Sequence analysis revealed four intra-genic single nucleotide polymorphisms. The valine residue at V289I was conserved in other eukaryotic species, whereas its frequency was approximately 65% in humans. We performed linkage and linkage disequilibrium analyses in two NIMH bipolar pedigree series using four tightly linked simple tandem repeat polymorphisms (STRPs) and the V289I. These analyses overall failed to support a role for DIBD1 in disease susceptibility. The most-significant finding was a lod score of 1.18 (P=0.0098), obtained by an intronic STRP D11S5025, in the subset of 22 multiplex pedigrees. In conclusion, we found that a mannosyltransferase gene at 11q23 is disrupted by a translocation breakpoint co-segregating with BPAD in a family. However, its role in the disease susceptibility remains unconfirmed. Electronic Publication  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