全文获取类型
收费全文 | 5262288篇 |
免费 | 404743篇 |
国内免费 | 16509篇 |
专业分类
耳鼻咽喉 | 75940篇 |
儿科学 | 164070篇 |
妇产科学 | 139499篇 |
基础医学 | 778592篇 |
口腔科学 | 150103篇 |
临床医学 | 479139篇 |
内科学 | 961728篇 |
皮肤病学 | 121513篇 |
神经病学 | 436630篇 |
特种医学 | 207860篇 |
外国民族医学 | 1376篇 |
外科学 | 800416篇 |
综合类 | 148551篇 |
现状与发展 | 23篇 |
一般理论 | 2857篇 |
预防医学 | 437065篇 |
眼科学 | 126116篇 |
药学 | 378896篇 |
27篇 | |
中国医学 | 13622篇 |
肿瘤学 | 259517篇 |
出版年
2021年 | 56719篇 |
2019年 | 59417篇 |
2018年 | 76118篇 |
2017年 | 58258篇 |
2016年 | 64817篇 |
2015年 | 77335篇 |
2014年 | 112275篇 |
2013年 | 177882篇 |
2012年 | 143439篇 |
2011年 | 151559篇 |
2010年 | 131433篇 |
2009年 | 131535篇 |
2008年 | 138609篇 |
2007年 | 149101篇 |
2006年 | 156538篇 |
2005年 | 151434篇 |
2004年 | 151952篇 |
2003年 | 141999篇 |
2002年 | 132167篇 |
2001年 | 209847篇 |
2000年 | 208744篇 |
1999年 | 187086篇 |
1998年 | 78080篇 |
1997年 | 72266篇 |
1996年 | 70064篇 |
1995年 | 65714篇 |
1994年 | 59724篇 |
1993年 | 55343篇 |
1992年 | 141126篇 |
1991年 | 136446篇 |
1990年 | 130899篇 |
1989年 | 127492篇 |
1988年 | 117977篇 |
1987年 | 115970篇 |
1986年 | 109673篇 |
1985年 | 107038篇 |
1984年 | 85919篇 |
1983年 | 75417篇 |
1982年 | 54529篇 |
1981年 | 50341篇 |
1980年 | 47181篇 |
1979年 | 77066篇 |
1978年 | 58936篇 |
1977年 | 51818篇 |
1976年 | 47913篇 |
1975年 | 49137篇 |
1974年 | 56329篇 |
1973年 | 54052篇 |
1972年 | 50734篇 |
1971年 | 46946篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Chromogenic ionophore-based methods for spectrophotometric assay of sodium and potassium in serum and plasma 总被引:1,自引:0,他引:1
A Kumar E Chapoteau B P Czech C R Gebauer M Z Chimenti O Raimondo 《Clinical chemistry》1988,34(9):1709-1712
We report spectrophotometric methods for quantifying sodium and potassium in serum and plasma without sample pretreatment or solvent-extraction steps. The methods are based on novel chromogenic ionophores characterized by molecular structures highly preorganized for binding, which result in exceptionally high sensitivity and selectivity (negligible responses to sodium at 80 to 200 mmol/L in the potassium assay and to potassium at 0 to 10 mmol/L in the sodium assay). The within-run imprecisions are comparable with those for ion-selective electrodes (for K, 1.0% at 4.5 mmol/L; for Na, 1.1% at 136 mmol/L); the analytical range is 2-10 mmol/L for potassium, 80-170 mmol/L for sodium. The results for greater than 100 patients' samples correlated well with results obtained with ion-selective electrodes (r = 0.99 for K, 0.97 for Na). The ready-to-use aqueous reagents will be available under the trade name of ChromoLyte for use with Technicon's RA family of clinical analyzers. 相似文献
992.
B A Thornhill H T Morehouse J C Hoffman-Tretin 《Critical reviews in diagnostic imaging》1988,28(1):1-22
Computed tomography (CT) is currently the imaging modality of choice for assessing the morphology of the adrenal glands in adult patients. Much useful information can be gained using CT in disease processes which primarily involve one or both of the adrenal glands, such as adenomas, as well as in entities which secondarily affect the adrenals, such as pituitary or metastatic disease. The size and configuration of the glands can be readily determined, and masses may be detected. We discuss CT of normal and abnormal adrenal glands with sonographic (US) and pathological correlation, when available. Entities which may mimic adrenal abnormalities are emphasized. Relative advantages of US over CT in the pediatric patient are discussed. 相似文献
993.
994.
995.
996.
Excretory/secretory antigen of Toxocara canis: recognition profiles of polyclonal and larvicidal monoclonal antibodies 总被引:1,自引:1,他引:0
Summary Five monoclonal antibodies against the excretory/secretory (E/S) antigen of Toxocara canis were obtained and characterized. Immunoprecipitating activity was demonstrated in an in-vitro micropre-cipitating assay using live T. canis larvae. Their capacity to kill larvae was also shown in an in-vitro assay. Two zones of reactivity were observed in 7.5 and 12.5% SDS-PAGE (177-77 kD, 43-15 kD) of immunoprecipitates of human and mouse positive polyclonal anlisera. The murine monoclonal antibodies showed a common pattern of reactivity with the proteins in the 177-77 kD range. 相似文献
997.
Edward R. Westrick MS Allan P. Shapiro PhD Peter E. Nathan PhD John Brick PhD 《Alcoholism, clinical and experimental research》1988,12(4):531-533
The present study demonstrates that alcohol-induced memory impairment can be attenuated by pretreatment with an oral tryptophan supplementation. These results provide support for the role of a brain serotonin deficit in this impairment and highlight the impact a dietary manipulation can have on a complex behavioral process. 相似文献
998.
Milton G. Mutchnick MD Horchang H. Lee MD 《Alcoholism, clinical and experimental research》1988,12(1):155-158
Concanavalin A-induced lymphocyte proliferation was studied in 25 patients with alcoholic hepatitis or compensated alcoholic cirrhosis. Nine alcoholics without evidence of liver disease were also evaluated. A nonlinear correlation equation, which was natural logarithmic, was applied to individual dose-response proliferation curves and permitted comparisons between patient groups and controls. The proliferative response in all patient groups was significantly lower when compared to healthy controls and was independent of the presence or absence of liver disease. This suggests that some changes in immune function observed in alcoholics may be linked to the direct effects of alcohol on the immune system rather than to the associated liver disease. 相似文献
999.
Tissue-specific regulation of pyroglutamate aminopeptidase II activity by thyroid hormones 总被引:2,自引:0,他引:2
Among the enzymes capable of degrading thyrotropin-releasing hormone (TRH) in vitro, two pyroglutamate aminopeptidases (PGA) are specific for TRH: thyroliberinase, a seric enzyme and PGAII, a membrane-bound peptidase. The effect of thyroid hormone status on the activity of these enzymes was evaluated in serum and various tissues. Only in adenohypophysis, triiodothyronine treatment increased PGAII to 376% of control; hypothyroidism produced the reverse effect (decrease to 23% of control). As previously reported, similar changes were observed for thyroliberinase. TRH degradation at the adenohypophysis level may participate in the negative feedback control of thyroid hormones. 相似文献
1000.
A novel hybridoma antibody (PASE/4LJ) to human prostatic acid phosphatase suitable for immunohistochemistry 总被引:2,自引:0,他引:2
A M Haines S E Larkin A P Richardson R W Stirling E Heyderman 《British journal of cancer》1989,60(6):887-892
A murine monoclonal antibody PASE/4LJ to prostatic acid phosphatase (PAP) was used to immunostain a wide variety of sections of benign and malignant tissues (654 blocks). Non-neoplastic adult and fetal prostatic glands, primary and metastatic prostatic carcinomas, and scattered cells in prostatic and penile urethra were positive. Rat, dog and rabbit prostates were negative. Nine of 400 tumours of non-prostatic origin showed some positivity: 6/36 carcinoids, 1/9 islet cell tumours, 1/55 ovarian adenocarcinomas (serous) and one carcinosarcoma of the lung (epithelial portion). Positive staining was seen in islet cells in 4/5 specimens of normal pancreas, and in 4/9 blocks of normal pancreas surrounding a pancreatic tumour. Loops of Henle, maculae densae, and distal tubules in 10/10 fetal and 2/9 adult kidneys were also positive, with proximal tubules and collecting ducts negative. All other 159 blocks of non-neoplastic adult and fetal tissues were negative. The antibody was also affinity purified from ascitic fluid, and shown not to inhibit the enzyme activity of prostatic acid phosphatase. 相似文献