全文获取类型
收费全文 | 46754篇 |
免费 | 3414篇 |
国内免费 | 164篇 |
专业分类
耳鼻咽喉 | 701篇 |
儿科学 | 1074篇 |
妇产科学 | 700篇 |
基础医学 | 5727篇 |
口腔科学 | 758篇 |
临床医学 | 5290篇 |
内科学 | 8997篇 |
皮肤病学 | 608篇 |
神经病学 | 4140篇 |
特种医学 | 1811篇 |
外国民族医学 | 2篇 |
外科学 | 8151篇 |
综合类 | 765篇 |
现状与发展 | 1篇 |
一般理论 | 32篇 |
预防医学 | 3751篇 |
眼科学 | 993篇 |
药学 | 3541篇 |
1篇 | |
中国医学 | 75篇 |
肿瘤学 | 3214篇 |
出版年
2023年 | 309篇 |
2022年 | 468篇 |
2021年 | 1223篇 |
2020年 | 644篇 |
2019年 | 1204篇 |
2018年 | 1420篇 |
2017年 | 1023篇 |
2016年 | 1037篇 |
2015年 | 1263篇 |
2014年 | 1856篇 |
2013年 | 2372篇 |
2012年 | 3616篇 |
2011年 | 3865篇 |
2010年 | 2118篇 |
2009年 | 1788篇 |
2008年 | 3115篇 |
2007年 | 3421篇 |
2006年 | 3248篇 |
2005年 | 3102篇 |
2004年 | 2716篇 |
2003年 | 2705篇 |
2002年 | 2408篇 |
2001年 | 349篇 |
2000年 | 229篇 |
1999年 | 348篇 |
1998年 | 487篇 |
1997年 | 333篇 |
1996年 | 288篇 |
1995年 | 290篇 |
1994年 | 245篇 |
1993年 | 203篇 |
1992年 | 166篇 |
1991年 | 144篇 |
1990年 | 142篇 |
1989年 | 148篇 |
1988年 | 140篇 |
1987年 | 125篇 |
1986年 | 105篇 |
1985年 | 135篇 |
1984年 | 149篇 |
1983年 | 139篇 |
1982年 | 167篇 |
1981年 | 141篇 |
1980年 | 157篇 |
1979年 | 75篇 |
1978年 | 91篇 |
1977年 | 66篇 |
1976年 | 52篇 |
1975年 | 54篇 |
1974年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
91.
92.
Polyclonal antibodies recognizing the pyridyloxobutyl (POB) moiety of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were produced in rabbits immunized either with POB-bovine albumin or POB-Sepharose. The POB intermediates necessary to modify the protein were generated by alkaline (pH 9.0) treatment of the synthetic precursor 4-(carbethoxynitrosamino)-1-(3-pyridyl)-1-butanone. In a competitive enzyme linked immunoabsorbent assay (ELISA), 70 pmole NNK inhibited 50% of the binding of the anti-POB antibodies to POB-protein absorbed on microtiterplates. This 50% inhibition varied from 70 pmole to 200 nmole using a series of NNK analogues, depending on the integrity of the POB moiety. Immunological techniques initiated in this study detect NNK-protein conjugates or measure the quantity of POB groups liberated upon alkaline or acid treatment of NNK modified protein. 相似文献
93.
Management of cerebral hemispherectomy in children 总被引:4,自引:0,他引:4
Surgical removal of a cerebral hemisphere may be undertaken in patients with intractable seizure disorders. Anesthetic management of such patients has not been reviewed in detail before. This study retrospectively analyzed hospital records of ten patients undergoing cerebral hemispherectomy at the Johns Hopkins Hospital between July 1983 and February 1988. Patient records were reviewed for diagnosis, physical characteristics, preoperative medications, anesthetic management, and postoperative course in the intensive care unit (ICU). Massive and sudden blood loss was a common finding in these patients, and during the intraoperative and postoperative periods, fluid resuscitation frequently was an ongoing process. In some patients, the blood loss exceeded one blood volume and was associated with coagulopathy, hypokalemia, and hypothermia. Urine output was elevated by a glucose-induced diuresis in some patients, giving misleading information as to intravascular volume status. Seizures and hemorrhage into the hemispherectomy cavity were management problems in the ICU. From this review, the authors conclude that blood loss may be marked and precipitous during surgical removal of a cerebral hemisphere. Monitoring of intra-arterial pressure and central venous pressure (CVP) is necessary for patient management during the intraoperative and postoperative periods. Intravenous (IV) access should allow rapid intravascular volume administration as it becomes necessary. Patients should remain intubated and observed closely during the immediate postoperative period due to difficulties with hemodynamic stability, seizures, and hemorrhage. 相似文献
94.
Laura J. Solomon Ph.D. Ruth M. Mickey Ph.D. C.J. Rairikar M.A. John K. Worden Ph.D. Brian S. Flynn Sc.D. 《Preventive medicine》1998,27(6):781-786
Background.This study prospectively examined rates of adherence to mammography, clinical breast examination (CBE), and breast self-examination (BSE) in a cohort of women over 3 years to determine whether participation in BSE influenced participation in the other two screening modalities.Methods.Women ages 51 and older (n= 450) who attended a small group educational session to learn BSE and to hear about CBE and mammography guidelines were assessed annually by telephone for 3 consecutive years to determine their subsequent breast cancer screening behavior.Results.Annual CBE and mammography screening are highly positively associated. Regular performance of BSE has a modest positive association with both CBE and mammography adherence over time.Conclusions.Women who perform BSE regularly over time may be more likely to adhere to the other breast cancer screening guidelines. 相似文献
95.
Robert D. Felner Stephen Brand Kay Erwin Mulhall Brian Counter Joyce B. Millman Judy Fried 《The journal of primary prevention》1994,15(2):123-146
A partnership between corporate worksites, a community-based prevention agency, and families in those worksites is described. Its primary goals were the reduction of family risk and enhancement of family protective factors that predispose children and youth to substance abuse and related social and emotional difficulties. A related goal of the program is to reduce family stress levels and attitudes that may influence the parents' levels of risk for substance abuse and related disorder. The program delivery strategy is conceived of as part of the necessart efforts of prevention programs to reach target populations in host settings in which they may naturally participate, thereby reducing obstacles and barriers to participation that often impede prevention efforts. Evaluation revealed that the program was generally better able to retain parents for a fairly lengthy period, and with high rates of attendance. Program attendance was also not affected by parental background characteristics that, in other delivery approaches, are often associated with poor attendance and high drop-out levels. Results also indicated that levels of program exposure (dosage) do make a significant difference in the efficacy of such efforts as those parents in the program who participated in higher percentages and numbers of sessions (i.e. more than 80% of sessions) showed both short-term and longer-term (i.e. across 18 month follow-ups) gains in their ratings of the target child's behavior problems and strengths, substance abuse resistance related knowledge and attitudes, reduced parental stress, depression and irritability, and increased utilization of social support. By contrast, parents who received a low program exposure exhibited a more restricted set of short-term gains. The findings are discussed in terms of their importance for consideration of program dosage for prevention programs, and the need to attend to the context in which programming is offered as it may facilitate or impede efforts to provide levels of dosage and fidelity to create enduring impacts 相似文献
96.
OBJECTIVE: Restraint use is not monitored in the US, and only institutions that choose to do so collect statistics. In 1999, investigative journalists reported lethal consequences proximal to restraint use, making it a life-and-death matter that demands attention from professionals. This paper reviews the literature concerning actual and potential causes of deaths proximal to the use of physical restraint. METHOD: Searching the electronic databases Medline, Cinahl, and PsycINFO, we reviewed the areas of forensics and pathology, nursing, cardiology, immunology, psychology, neurosciences, psychiatry, emergency medicine, and sports medicine. CONCLUSIONS: Research is needed to provide clinicians with data on the risk factors and adverse effects associated with restraint use, as well as data on procedures that will lead to reduced use. Research is needed to determine what individual risk factors and combinations thereof contribute to injury and death. 相似文献
97.
98.
Achilles tendon overuse injuries. 总被引:5,自引:0,他引:5
Overuse injuries of the Achilles tendon are common in patients engaging in recreational athletics. Achilles tendon overuse injuries exist as a spectrum of diseases ranging from inflammation of the paratendinous tissue (paratenonitis), to structural degeneration of the tendon (tendinosis), and finally tendon rupture. Factors known to predispose patients to Achilles tendinitis include inadequate stretching, training errors, mechanical malalignment of the lower extremities, rigid training surfaces, and occasionally systemic disease. Treatment of the patient with paratenonitis and tendinosis is initially conservative, emphasizing passive stretching, concentric and eccentric strengthening, correction of training errors, and restoration of normal limb alignment. Patients resistant to this protocol often exhibit a more advanced degree of tendon change. A high percentage of these patients can benefit from surgical debridement of the involved tendon, and they can anticipate successful return to recreational athletics. Steroid injections should not be routinely used in patients with Achilles tendinitis. Rupture of the Achilles tendon following intratendinous injection has been reported. 相似文献
99.
Robert T. Cook Thomas J. Waldschmidt Zuhair K. Ballas Brian L. Cook Brenda M. Booth Barbara C. Stewart Michael J. Garvey 《Alcoholism, clinical and experimental research》1994,18(1):71-80
Alcoholics admitted to the hospital solely for detoxication have been studied by flow cytometry to evaluate changes in the surface markers of peripheral blood leukocytes. As we have shown previously, such patients have an elevated percentage of CD8hl lymphocytes that are HLA DR+; we now demonstrate that they also have striking alterations in the quantitative relationships of the fine T-cell subsets. Both CD4+ and CD8hl lymphocytes have a sharply reduced percentage of the l -selectin+ CD45RA+ subset, increased percentages of the CD45RA-subsets, and several other fine subset alterations. The fine subset profile suggests, according to current correlations of phenotype and function, that both CD4+ suppressor inducer and CD4-dependent CD8+ suppressor effector cells are reduced, whereas other subsets, including CD8+ CTL or their precursors, are increased in relative percentages. Some of the phenotypic changes are reversible over the several days following withdrawal. In other results, the percentage of CD8hl lymphocytes expressing CD11b (β-integrin) is shown to be reciprocal with the percentage expressing l -selectin both in normals and alcoholics. However, the regression function of CD11b vs. l -selectin on CD8hl cells is different for the alcoholics than for the normals, indicating an abnormality in the regulation of the expression of these two adhesion markers. Taken together, this abnormality of adhesion molecules and the fine subset alterations previously described indicate widespread changes in the peripheral lymphocytes of currently drinking alcoholics. These changes suggest functional deficiencies that may include alterations of lymphocyte traffic and other adhesion-dependent functions, and a shift in the balance of regulatory interactions. 相似文献
100.